Add TianDiTu

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/copilot-instructions.md

@@ -0,0 +1,5 @@
+# GitHub Copilot Instructions
+
+Read `AGENTS.md` first, then `CLAUDE.md`.
+
+`AGENTS.md` contains the architecture, module boundaries, implementation details, conventions, and gotchas.

.github/workflows/release.yml

@@ -16,13 +16,13 @@ jobs:
       contents: write
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Setup Java
         uses: actions/setup-java@v5
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v6
@@ -58,10 +58,11 @@ jobs:
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '3.3'
+          ruby-version: '3.4'
 
       - name: Deploy Bundle to Google Play
         run: |
+          gem install multi_json
           gem install fastlane --no-document
           AAB=$(find app/build/outputs/bundle/release -name "*.aab" | head -1)
           echo '${{ secrets.SERVICE_ACCOUNT_JSON }}' > service_account.json

AGENTS.md

@@ -0,0 +1,122 @@
+# Look4Sat AI Agent Instructions
+
+This is the canonical project guide for all AI assistants working on Look4Sat.
+All assistant-specific files (`CLAUDE.md`, `.github/copilot-instructions.md`) point here.
+
+---
+
+## Project Overview
+
+Look4Sat is an open-source, fully offline Android satellite tracker and pass predictor. It tracks 9000+ active
+satellites using TLE/OMM data from Celestrak/SatNOGS, calculates orbital positions via SGP4/SDP4 models, and displays
+passes relative to the user's location. Features include polar radar visualization, SSTV image decoding, satellite
+ground track mapping, and pass predictions up to 10 days ahead. No ads, no tracking, no network required after initial
+data download.
+
+## Architecture
+
+**MVI (Model-View-Intent)** with unidirectional data flow:
+- `State` data class → exposed via `StateFlow` from ViewModel
+- `Action` sealed interface → user intents dispatched to ViewModel's `onAction()`
+- Jetpack Compose UI observes state and recomposes reactively
+
+**Clean Architecture layers:**
+
+| Module               | Responsibility                                                      |
+|----------------------|---------------------------------------------------------------------|
+| `app`                | Entry point. Aggregates all modules                                 |
+| `core:data`          | Android library. Room DB, OkHttp networking, repo implementations   |
+| `core:domain`        | Pure Kotlin (JVM). Orbital math (SGP4/SDP4), models, repo contracts |
+| `core:presentation`  | Android library. Compose theme, shared UI components, NavKeys       |
+| `feature:map`        | OSMDroid map with ground tracks                                     |
+| `feature:passes`     | Pass predictions and upcoming events                                |
+| `feature:radar`      | Polar radar view of satellite positions, SSTV image decoding        |
+| `feature:satellites` | Satellite list, filtering, selection                                |
+| `feature:settings`   | User preferences                                                    |
+
+- `feature:*` modules depend only on `core:domain` + `core:presentation`. Features never depend on each other.
+
+## Build & Run
+
+```shell
+# Debug build
+./gradlew assembleDebug
+
+# Release build (minified, shrunk resources)
+./gradlew assembleRelease
+
+# Run tests
+./gradlew test
+```
+
+- **Min SDK**: 24 | **Target SDK**: 36 | **JDK**: 17
+- **Gradle**: Uses version catalog (`gradle/libs.versions.toml`) + convention plugins in `build-logic/`
+
+## Key Libraries
+
+- **Compose** (BOM 2026.05.01) + Material3 Adaptive
+- **Navigation3** (type-safe, uses `@Serializable` NavKeys)
+- **Room** (KSP code generation) for local satellite/TLE storage
+- **OkHttp** 5.x for TLE downloads
+- **OSMDroid** for map rendering
+- **Kotlin Serialization** for navigation args and data parsing
+- **Coroutines** + `StateFlow` for async/reactive patterns
+
+## Conventions
+
+- **Minimal dependencies**: Avoid adding libraries when a simple manual solution exists. Fewer deps = less maintenance.
+- **DI**: Manual — ViewModels use companion `factory()` methods with `IMainContainer` interface.
+- **Navigation**: Type-safe Compose Navigation3 with `@Serializable` data classes as nav keys.
+- **State naming**: `<Feature>State` data class + `<Feature>Action` sealed interface per feature.
+- **No feature-to-feature deps**: All cross-feature communication goes through core layers.
+- **Localization**: 7 languages (en, es, ru, si, tr, uk, zh).
+
+## Data Formats & Migration
+
+**TLE vs. OMM/CSV format:**
+
+Look4Sat supports both TLE and OMM (Orbit Mean-Elements Message) formats for backward compatibility:
+
+- **TLE format**: Traditional 3-line element format (deprecated). NORAD catalog numbers are 5-digit integers, which
+  are running out of space. Celestrak has signaled that TLE format will eventually be phased out.
+- **OMM/CSV format**: The future standard. CSV files contain the same orbital parameters as TLE but use ISO 8601
+  timestamps and support larger NORAD IDs. Celestrak and SatNOGS already provide OMM data in CSV format.
+
+**Current implementation:**
+- `DataParser.kt` handles both `parseTLEStream()` and `parseCSVStream()` seamlessly
+- TLE data is downloaded from configured sources and stored in Room database
+- When downloading satellite data, the app automatically detects format and parses accordingly
+- Both formats produce identical `OrbitalData` objects, ensuring transparent format switching
+
+**Migration path:**
+As NORAD catalog space becomes constrained, OMM/CSV will become the primary format. Look4Sat is already positioned
+to handle this transition without code changes — existing users can continue using TLE files while new sources
+transition to OMM/CSV automatically.
+
+## Code Style
+
+- Prefer **short, focused functions** — single responsibility, easy to read.
+- **Exceptions**: Composable functions and math-heavy algorithms (SGP4/SDP4) may be longer.
+- Strict code style — no dead code, no unused imports, consistent formatting.
+
+## Roadmap
+
+- **KMP migration**: `core:domain` is to become a fully shareable KMM module. Keep it pure Kotlin/JVM.
+
+## Gotchas
+
+- Orbital math lives in `core:domain/predict/` — it's dense vector math (SGP4/SDP4). Tread carefully.
+- TLE/OMM data must be refreshed weekly for accurate predictions (satellite orbits decay). TLE format is legacy and
+  will eventually be deprecated in favor of OMM/CSV as NORAD catalog numbers approach the 5-digit limit.
+- SSTV decoding in `feature:radar` is experimental; image quality depends on signal strength during satellite pass.
+- `build-logic/convention/` contains all shared Gradle configuration — edit there, not in individual modules.
+- ProGuard is enabled for release builds — don't add reflection-based libs or any other dependencies without asking.
+
+## Copilot Working Mode: Code-Only
+
+- Default to code changes only. Provide explanations in chat only.
+- If documentation seems useful, ask first before creating files.
+- Do NOT create any `.md` documentation files unless explicitly requested.
+- Do NOT add README, guides, summaries, migration notes, or how-to files unless asked.
+- Prefer minimal diffs focused on requested implementation.
+- Default validation is static checks (`get_errors`). Do NOT run Gradle compile/test tasks unless explicitly requested.

CLAUDE.md

@@ -1,110 +1,5 @@
 # CLAUDE.md
 
-## Project Overview
+Read `AGENTS.md` first, then follow the instructions there.
 
-Look4Sat is an open-source, fully offline Android satellite tracker and pass predictor. It tracks 9000+ active
-satellites using TLE/OMM data from Celestrak/SatNOGS, calculates orbital positions via SGP4/SDP4 models, and displays
-passes relative to the user's location. Features include polar radar visualization, SSTV image decoding, satellite
-ground track mapping, and pass predictions up to 10 days ahead. No ads, no tracking, no network required after initial
-data download.
-
-## Architecture
-
-**MVI (Model-View-Intent)** with unidirectional data flow:
-- `State` data class → exposed via `StateFlow` from ViewModel
-- `Action` sealed interface → user intents dispatched to ViewModel's `onAction()`
-- Jetpack Compose UI observes state and recomposes reactively
-
-**Clean Architecture layers:**
-
-| ------------------------ | --------------------------------------------------------------------- |
-| Module                   | Responsibility                                                        |
-|--------------------------|-----------------------------------------------------------------------|
-| `app`                    | Entry point. Aggregates all modules                                   |
-| `core:data`              | Android library. Room DB, OkHttp networking, repo implementations     |
-| `core:domain`            | Pure Kotlin (JVM). Orbital math (SGP4/SDP4), models, repo contracts   |
-| `core:presentation`      | Android library. Compose theme, shared UI components, NavKeys         |
-| `feature:map`            | OSMDroid map with ground tracks                                       |
-| `feature:passes`         | Pass predictions and upcoming events                                  |
-| `feature:radar`          | Polar radar view of satellite positions, SSTV image decoding              |
-| `feature:satellites`     | Satellite list, filtering, selection                                  |
-| `feature:settings`       | User preferences                                                      |
-| ------------------------ | --------------------------------------------------------------------- |
-
-- `feature:*` modules depend only on `core:domain` + `core:presentation`. Features never depend on each other.
-
-## Build & Run
-
-```shell
-# Debug build
-./gradlew assembleDebug
-
-# Release build (minified, shrunk resources)
-./gradlew assembleRelease
-
-# Run tests
-./gradlew test
-```
-
-- **Min SDK**: 24 | **Target SDK**: 36 | **JDK**: 17
-- **Gradle**: Uses version catalog (`gradle/libs.versions.toml`) + convention plugins in `build-logic/`
-
-## Key Libraries
-
-- **Compose** (BOM 2026.05.01) + Material3 Adaptive
-- **Navigation3** (type-safe, uses `@Serializable` NavKeys)
-- **Room** (KSP code generation) for local satellite/TLE storage
-- **OkHttp** 5.x for TLE downloads
-- **OSMDroid** for map rendering
-- **Kotlin Serialization** for navigation args and data parsing
-- **Coroutines** + `StateFlow` for async/reactive patterns
-
-## Conventions
-
-- **Minimal dependencies**: Avoid adding libraries when a simple manual solution exists. Fewer deps = less maintenance.
-- **DI**: Manual — ViewModels use companion `factory()` methods with `IMainContainer` interface.
-- **Navigation**: Type-safe Compose Navigation3 with `@Serializable` data classes as nav keys.
-- **State naming**: `<Feature>State` data class + `<Feature>Action` sealed interface per feature.
-- **No feature-to-feature deps**: All cross-feature communication goes through core layers.
-- **Localization**: 7 languages (en, es, ru, si, tr, uk, zh).
-
-## Data Formats & Migration
-
-**TLE vs. OMM/CSV format:**
-
-Look4Sat supports both TLE and OMM (Orbit Mean-Elements Message) formats for backward compatibility:
-
-- **TLE format**: Traditional 3-line element format (deprecated). NORAD catalog numbers are 5-digit integers, which
-  are running out of space. Celestrak has signaled that TLE format will eventually be phased out.
-- **OMM/CSV format**: The future standard. CSV files contain the same orbital parameters as TLE but use ISO 8601
-  timestamps and support larger NORAD IDs. Celestrak and SatNOGS already provide OMM data in CSV format.
-
-**Current implementation:**
-- `DataParser.kt` handles both `parseTLEStream()` and `parseCSVStream()` seamlessly
-- TLE data is downloaded from configured sources and stored in Room database
-- When downloading satellite data, the app automatically detects format and parses accordingly
-- Both formats produce identical `OrbitalData` objects, ensuring transparent format switching
-
-**Migration path:**
-As NORAD catalog space becomes constrained, OMM/CSV will become the primary format. Look4Sat is already positioned
-to handle this transition without code changes—existing users can continue using TLE files while new sources transition
-to OMM/CSV automatically.
-
-## Code Style
-
-- Prefer **short, focused functions** — single responsibility, easy to read.
-- **Exceptions**: Composable functions and math-heavy algorithms (SGP4/SDP4) may be longer.
-- Strict code style — no dead code, no unused imports, consistent formatting.
-
-## Roadmap
-
-- **KMP migration**: `core:domain` is to become a fully shareable KMM module. Keep it pure Kotlin/JVM.
-
-## Gotchas
-
-- Orbital math lives in `core:domain/predict/` — it's dense vector math (SGP4/SDP4). Tread carefully.
-- TLE/OMM data must be refreshed weekly for accurate predictions (satellite orbits decay). TLE format is legacy and
-  will eventually be deprecated in favor of OMM/CSV as NORAD catalog numbers approach the 5-digit limit.
-- SSTV decoding in `feature:radar` is experimental; image quality depends on signal strength during satellite pass.
-- `build-logic/convention/` contains all shared Gradle configuration — edit there, not in individual modules.
-- ProGuard is enabled for release builds — don't add reflection-based libs or any other dependencies without asking.
+`AGENTS.md` contains the architecture, module boundaries, implementation details, conventions, and gotchas.

README.md

@@ -33,3 +33,13 @@ It is now and always will be completely ad-free and open-source.
 *  Showing the satellite positional data, footprint and ground track on the map
 *  Custom TLE satellite data import is available via Three Line Element .txt files
 *  Offline first: calculations are made offline. Weekly TLE data update is recommended.
+
+## Star History
+
+<a href="https://www.star-history.com/?repos=rt-bishop%2FLook4Sat&type=timeline&legend=top-left">
+ <picture>
+   <source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/chart?repos=rt-bishop/Look4Sat&type=timeline&theme=dark&legend=top-left" />
+   <source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/chart?repos=rt-bishop/Look4Sat&type=timeline&legend=top-left" />
+   <img alt="Star History Chart" src="https://api.star-history.com/chart?repos=rt-bishop/Look4Sat&type=timeline&legend=top-left" />
+ </picture>
+</a>

app/proguard-rules.pro

@@ -0,0 +1,3 @@
+-keep class org.osmdroid.** { *; }
+-keep class com.rtbishop.look4sat.feature.map.*TiandituTileSource* { *; }
+-dontwarn org.osmdroid.**

app/src/main/AndroidManifest.xml

@@ -2,6 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_LOCAL_NETWORK" />
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
     <uses-permission
@@ -14,26 +15,34 @@
     <uses-permission android:name="android.permission.RECORD_AUDIO" />
 
     <application
-        android:name=".MainApplication"
+        android:name="cn.bh2vsq.look4sat.MainApplication"
         android:allowBackup="false"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
-        android:roundIcon="@mipmap/ic_launcher_round"
-        android:usesCleartextTraffic="true">
+        android:networkSecurityConfig="@xml/network_security_config"
+        android:roundIcon="@mipmap/ic_launcher_round">
 
         <activity
-            android:name=".MainActivity"
+            android:name="cn.bh2vsq.look4sat.MainActivity"
             android:exported="true"
             android:theme="@style/Theme.Look4Sat.SplashScreen">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+<!--            <intent-filter android:autoVerify="true">-->
+<!--                <action android:name="android.intent.action.VIEW" />-->
+<!--                <category android:name="android.intent.category.DEFAULT" />-->
+<!--                <category android:name="android.intent.category.BROWSABLE" />-->
+<!--                <data android:scheme="https" />-->
+<!--                <data android:host="github.com" />-->
+<!--                <data android:pathPattern="/rt-bishop/Look4Sat/passes.*" />-->
+<!--            </intent-filter>-->
         </activity>
 
         <meta-data
             android:name="android.telephony.PROPERTY_SATELLITE_DATA_OPTIMIZED"
-            android:value="com.rtbishop.look4sat" />
+            android:value="cn.bh2vsq.look4sat" />
 
     </application>
 </manifest>

app/src/main/java/cn/bh2vsq/look4sat/MainActivity.kt

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package com.rtbishop.look4sat
+package cn.bh2vsq.look4sat
 
 import android.content.Context
 import android.content.res.Configuration

app/src/main/java/cn/bh2vsq/look4sat/MainApplication.kt

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package com.rtbishop.look4sat
+package cn.bh2vsq.look4sat
 
 import android.app.Application
 import com.rtbishop.look4sat.core.data.injection.MainContainer

app/src/main/java/cn/bh2vsq/look4sat/MainScreen.kt

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package com.rtbishop.look4sat
+package cn.bh2vsq.look4sat
 
 import androidx.compose.animation.core.LinearEasing
 import androidx.compose.animation.core.RepeatMode
@@ -25,6 +25,10 @@ import androidx.compose.animation.core.rememberInfiniteTransition
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
+import androidx.compose.animation.scaleIn
+import androidx.compose.animation.scaleOut
+import androidx.compose.animation.slideInHorizontally
+import androidx.compose.animation.slideOutHorizontally
 import androidx.compose.animation.togetherWith
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
@@ -32,6 +36,7 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
@@ -39,11 +44,13 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteDefaults
 import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteScaffold
 import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteType
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -62,6 +69,8 @@ import androidx.navigation3.runtime.rememberNavBackStack
 import androidx.navigation3.runtime.rememberSaveableStateHolderNavEntryDecorator
 import androidx.navigation3.ui.NavDisplay
 import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
+import com.rtbishop.look4sat.core.presentation.DeeplinkResolver
+import com.rtbishop.look4sat.core.presentation.RadarDestination
 import com.rtbishop.look4sat.core.presentation.Screen
 import com.rtbishop.look4sat.core.presentation.hasEnoughHeight
 import com.rtbishop.look4sat.core.presentation.hasEnoughWidth
@@ -72,13 +81,47 @@ import com.rtbishop.look4sat.feature.satellites.SatellitesDestination
 import com.rtbishop.look4sat.feature.settings.SettingsDestination
 
 @Composable
-fun MainScreen() {
+fun NavRoot(deeplink: String? = null) {
+    val rootBackStack = rememberNavBackStack(Screen.Passes)
+    val deeplinkResolver = DeeplinkResolver()
+    LaunchedEffect(deeplink) {
+        deeplink?.let {
+            val destination = deeplinkResolver.resolve(it) // rootBackStack.clear()
+            rootBackStack.add(destination)
+        }
+    }
+    val navigateBack: () -> Unit = { rootBackStack.removeLastOrNull() }
+    val slideInTransition = slideInHorizontally(initialOffsetX = { it }) togetherWith scaleOut(targetScale = 0.9f)
+    val slideOutTransition = scaleIn(initialScale = 0.9f) togetherWith slideOutHorizontally(targetOffsetX = { it })
+    NavDisplay(
+        modifier = Modifier.fillMaxSize(),
+        backStack = rootBackStack,
+        onBack = navigateBack,
+        transitionSpec = { slideInTransition },
+        popTransitionSpec = { slideOutTransition },
+        predictivePopTransitionSpec = { slideOutTransition },
+        entryDecorators = listOf(
+            rememberSaveableStateHolderNavEntryDecorator(), // Required for saving Compose state per entry
+            rememberViewModelStoreNavEntryDecorator() // Required for ViewModel scoping per entry
+        ),
+        entryProvider = entryProvider {
+            entry<Screen.Passes> { MainScreen(navigateToRadar = { rootBackStack.add(RadarDestination) }) }
+            entry<RadarDestination> {
+                Scaffold { innerPadding ->
+                    RadarDestination(navigateUp = navigateBack)
+                    innerPadding.calculateTopPadding()
+                }
+            }
+        }
+    )
+}
+
+@Composable
+fun MainScreen(navigateToRadar: () -> Unit = {}) {
     val backStack = rememberNavBackStack(Screen.Passes)
     val currentKey = backStack.lastOrNull()
-    val navigateBack: () -> Unit = { if (backStack.size > 1) backStack.removeAt(backStack.size - 1) }
+    val navigateBack: () -> Unit = { backStack.removeLastOrNull() }
     val fadeTransition = fadeIn(animationSpec = tween(350)) togetherWith fadeOut(animationSpec = tween(350))
-//    val slideInTransition = slideInHorizontally(initialOffsetX = { it }) togetherWith scaleOut(targetScale = 0.9f)
-//    val slideOutTransition = scaleIn(initialScale = 0.9f) togetherWith slideOutHorizontally(targetOffsetX = { it })
     val navItems = listOf(Screen.Satellites, Screen.Passes, Screen.Radar, Screen.Map, Screen.Settings)
 
     val context = LocalContext.current
@@ -139,6 +182,7 @@ fun MainScreen() {
                         PassesDestination { catNum, aosTime ->
                             container.satelliteRepo.selectPass(catNum, aosTime)
                             backStack.add(Screen.Radar)
+//                            navigateToRadar()
                         }
                     }
                     entry<Screen.Radar> {

app/src/main/res/xml/network_security_config.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<network-security-config>
+    <domain-config cleartextTrafficPermitted="true">
+        <domain includeSubdomains="true">tianditu.gov.cn</domain>
+    </domain-config>
+</network-security-config>

build-logic/convention/src/main/java/com/rtbishop/look4sat/convention/PluginSetupUtils.kt

@@ -69,7 +69,7 @@ internal fun Project.setupAndroidApp() {
             release {
                 isMinifyEnabled = true
                 isShrinkResources = true
-                proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"))
+                proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
             }
         }
         androidResources {

build.gradle.kts

@@ -8,5 +8,6 @@ plugins {
 }
 
 tasks.register("clean", Delete::class.java) {
+    description = "Cleans the build directory"
     delete(rootProject.layout.buildDirectory)
 }

core/data/src/main/AndroidManifest.xml

@@ -2,6 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_LOCAL_NETWORK" />
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
     <uses-permission

core/data/src/main/java/com/rtbishop/look4sat/core/data/framework/Ft817CatProtocol.kt

@@ -17,6 +17,9 @@
  */
 package com.rtbishop.look4sat.core.data.framework
 
+import java.util.Locale
+import kotlin.math.roundToLong
+
 object Ft817CatProtocol {
 
     const val CMD_SET_FREQ: Byte = 0x01
@@ -50,7 +53,7 @@ object Ft817CatProtocol {
     fun encodeFrequencyBcd(frequencyHz: Long): ByteArray {
         val freq10Hz = frequencyHz / 10
         val bcd = ByteArray(4)
-        val digits = String.format("%08d", freq10Hz)
+        val digits = String.format(Locale.US, "%08d", freq10Hz)
         for (i in 0 until 4) {
             val high = digits[i * 2] - '0'
             val low = digits[i * 2 + 1] - '0'
@@ -78,8 +81,8 @@ object Ft817CatProtocol {
      * 67.0 Hz → 670 (in 0.1 Hz) → BCD [0x06, 0x70]
      */
     fun encodeCtcssToneBcd(toneHz: Double): ByteArray {
-        val tone01Hz = (toneHz * 10).toLong()
-        val digits = String.format("%04d", tone01Hz)
+        val tone01Hz = (toneHz * 10).roundToLong()
+        val digits = String.format(Locale.US, "%04d", tone01Hz)
         val bcd = ByteArray(2)
         for (i in 0 until 2) {
             val high = digits[i * 2] - '0'
@@ -95,7 +98,7 @@ object Ft817CatProtocol {
     }
 
     fun buildSetModeCommand(mode: String): ByteArray? {
-        val modeByte = MODE_TO_BYTE[mode.uppercase()] ?: return null
+        val modeByte = MODE_TO_BYTE[mode.uppercase(Locale.US)] ?: return null
         return byteArrayOf(modeByte, 0x00, 0x00, 0x00, CMD_SET_MODE)
     }
 

core/data/src/main/java/com/rtbishop/look4sat/core/data/framework/Ft817Controller.kt

@@ -29,6 +29,7 @@ import kotlinx.coroutines.withContext
 import java.io.InputStream
 import java.io.OutputStream
 import java.util.UUID
+import kotlin.time.Duration.Companion.milliseconds
 
 class Ft817Controller(
     private val bluetoothManager: BluetoothManager,
@@ -39,10 +40,12 @@ class Ft817Controller(
     private val sppId: UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb")
     private val ioMutex = Mutex()
     private val commandDelayMs = 200L
+    private val maxAckReadFailures = 3
 
     private var socket: BluetoothSocket? = null
     private var outputStream: OutputStream? = null
     private var inputStream: InputStream? = null
+    private var ackReadFailureCount = 0
 
     override var isConnected: Boolean = false
         private set
@@ -57,6 +60,7 @@ class Ft817Controller(
             socket = btSocket
             outputStream = btSocket.outputStream
             inputStream = btSocket.inputStream
+            ackReadFailureCount = 0
             isConnected = true
             Log.i(tag, "Connected to $deviceAddress")
             true
@@ -79,6 +83,7 @@ class Ft817Controller(
                 inputStream = null
                 outputStream = null
                 socket = null
+                ackReadFailureCount = 0
                 isConnected = false
                 Log.i(tag, "Disconnected from $deviceAddress")
             }
@@ -112,8 +117,8 @@ class Ft817Controller(
         ioMutex.withLock {
             val sent = sendCommand(Ft817CatProtocol.buildReadFreqModeCommand())
             if (!sent) return@withContext null
-            delay(commandDelayMs)
-            val response = readResponse(5) ?: return@withContext null
+            delay(commandDelayMs.milliseconds)
+            val response = readResponse() ?: return@withContext null
             Ft817CatProtocol.parseReadResponse(response)
         }
     }
@@ -127,44 +132,76 @@ class Ft817Controller(
     }
 
     private suspend fun sendCommand(bytes: ByteArray): Boolean {
-        return try {
-            outputStream?.write(bytes) ?: return false
-            outputStream?.flush()
-            delay(commandDelayMs)
-            true
-        } catch (e: Exception) {
-            Log.e(tag, "Send error: ${e.message}")
-            isConnected = false
-            false
+        return withContext(Dispatchers.IO) {
+            try {
+                outputStream?.write(bytes) ?: return@withContext false
+                outputStream?.flush()
+                delay(commandDelayMs.milliseconds)
+                true
+            } catch (e: Exception) {
+                Log.e(tag, "Send error: ${e.message}")
+                isConnected = false
+                false
+            }
         }
     }
 
     /** Send command and read the 1-byte ACK response (0x00 = OK). */
     private suspend fun sendCommandWithAck(bytes: ByteArray): Boolean {
         if (!sendCommand(bytes)) return false
-        return try {
-            val ack = inputStream?.read() ?: return false
-            ack == 0x00
-        } catch (e: Exception) {
-            Log.e(tag, "ACK read error: ${e.message}")
-            true // command was sent, ACK read failed - continue anyway
+        return withContext(Dispatchers.IO) {
+            try {
+                val ack = inputStream?.read() ?: run {
+                    ackReadFailureCount = 0
+                    isConnected = false
+                    return@withContext false
+                }
+                if (ack < 0) {
+                    ackReadFailureCount = 0
+                    Log.i(tag, "ACK stream closed by remote device")
+                    isConnected = false
+                    return@withContext false
+                }
+                ackReadFailureCount = 0
+                ack == 0x00
+            } catch (e: Exception) {
+                ackReadFailureCount += 1
+                Log.w(tag, "ACK read error (${ackReadFailureCount}/$maxAckReadFailures): ${e.message}")
+                if (ackReadFailureCount >= maxAckReadFailures) {
+                    Log.e(tag, "Too many ACK read errors, marking radio disconnected")
+                    isConnected = false
+                    false
+                } else {
+                    true // Command was sent, treat transient ACK read failures as best-effort
+                }
+            }
         }
     }
 
-    private fun readResponse(length: Int): ByteArray? {
-        return try {
-            val buffer = ByteArray(length)
-            var read = 0
-            while (read < length) {
-                val count = inputStream?.read(buffer, read, length - read) ?: return null
-                if (count < 0) return null
-                read += count
+    private suspend fun readResponse(): ByteArray? {
+        return withContext(Dispatchers.IO) {
+            try {
+                val responseSize = 5
+                val buffer = ByteArray(responseSize)
+                var read = 0
+                while (read < responseSize) {
+                    val count = inputStream?.read(buffer, read, responseSize - read) ?: run {
+                        isConnected = false
+                        return@withContext null
+                    }
+                    if (count < 0) {
+                        Log.i(tag, "Response stream closed by remote device")
+                        isConnected = false
+                        return@withContext null
+                    }
+                    read += count
+                }
+                buffer
+            } catch (e: Exception) {
+                Log.e(tag, "Read error: ${e.message}")
+                isConnected = false
+                null
             }
-            buffer
-        } catch (e: Exception) {
-            Log.e(tag, "Read error: ${e.message}")
-            isConnected = false
-            null
         }
     }
 }

core/data/src/main/java/com/rtbishop/look4sat/core/data/injection/MainContainer.kt

@@ -19,10 +19,9 @@ package com.rtbishop.look4sat.core.data.injection
 
 import android.bluetooth.BluetoothManager
 import android.content.Context
-import android.hardware.Sensor
 import android.hardware.SensorManager
+import android.hardware.display.DisplayManager
 import android.location.LocationManager
-import android.view.WindowManager
 import androidx.room.Room
 import com.rtbishop.look4sat.core.data.database.Look4SatDb
 import com.rtbishop.look4sat.core.data.framework.BluetoothReporter
@@ -120,9 +119,8 @@ class MainContainer(private val context: Context) : IMainContainer {
 
     override fun provideSensorsRepo(): ISensorsRepo {
         val manager = context.getSystemService(Context.SENSOR_SERVICE) as SensorManager
-        val sensor = manager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR)
-        val window = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
-        return SensorsRepo(manager,sensor,window)
+        val displayManager = context.getSystemService(DisplayManager::class.java)
+        return SensorsRepo(manager, displayManager)
     }
 
     private fun provideDatabaseRepo(): IDatabaseRepo {

core/data/src/main/java/com/rtbishop/look4sat/core/data/repository/SensorsRepo.kt

@@ -22,8 +22,9 @@ import android.hardware.Sensor
 import android.hardware.SensorEvent
 import android.hardware.SensorEventListener
 import android.hardware.SensorManager
+import android.hardware.display.DisplayManager
+import android.view.Display
 import android.view.Surface
-import android.view.WindowManager
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.RAD2DEG
 import com.rtbishop.look4sat.core.domain.repository.ISensorsRepo
@@ -31,13 +32,16 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlin.math.round
 
+private const val SMOOTHING_FACTOR = 0.15f
+private const val SENSOR_RATE_US = 16_000
+
 class SensorsRepo(
     private val sensorManager: SensorManager,
-    private val sensor: Sensor?,
-    private val windowManager: WindowManager
-) : SensorEventListener, ISensorsRepo {
+    private val displayManager: DisplayManager?
+) : ISensorsRepo, SensorEventListener {
 
-    private val _orientation = MutableStateFlow(Pair(0f, 0f))
+    private val _sensorData = MutableStateFlow(Pair(0f, 0f))
+    private val sensor: Sensor? = sensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR)
     private val rotationMatrix = FloatArray(9)
     private val tempMatrix = FloatArray(9)
     private val orientationValues = FloatArray(3)
@@ -45,11 +49,7 @@ class SensorsRepo(
     private var smoothPitch = 0f
     private var hasInitialReading = false
 
-    companion object {
-        private const val SMOOTHING_FACTOR = 0.15f
-    }
-
-    override val orientation: StateFlow<Pair<Float, Float>> = _orientation
+    override val sensorData: StateFlow<Pair<Float, Float>> = _sensorData
 
     override fun getMagDeclination(geoPos: GeoPos, time: Long): Float {
         return GeomagneticField(
@@ -62,7 +62,7 @@ class SensorsRepo(
 
     override fun enableSensor() {
         hasInitialReading = false
-        sensor?.let { sensorManager.registerListener(this, it, 8000) }
+        sensor?.let { sensorManager.registerListener(this, it, SENSOR_RATE_US) }
     }
 
     override fun disableSensor() = sensorManager.unregisterListener(this)
@@ -70,16 +70,11 @@ class SensorsRepo(
     override fun onAccuracyChanged(sensor: Sensor, accuracy: Int) = Unit
 
     override fun onSensorChanged(event: SensorEvent) {
-        if (event.sensor == sensor) updateOrientation(event.values)
+        if (event.sensor.type == Sensor.TYPE_ROTATION_VECTOR) handleSensorEvent(event)
     }
 
     private fun getDisplayRotation(): Int {
-        return try {
-            @Suppress("DEPRECATION")
-            windowManager.defaultDisplay.rotation
-        } catch (_: Exception) {
-            Surface.ROTATION_0
-        }
+        return displayManager?.getDisplay(Display.DEFAULT_DISPLAY)?.rotation ?: Surface.ROTATION_0
     }
 
     private fun remapForRotation(rotation: Int) {
@@ -101,30 +96,23 @@ class SensorsRepo(
         if (remapped) System.arraycopy(tempMatrix, 0, rotationMatrix, 0, 9)
     }
 
-    private fun updateOrientation(rotationVector: FloatArray) {
-        SensorManager.getRotationMatrixFromVector(rotationMatrix, rotationVector)
+    private fun handleSensorEvent(event: SensorEvent) {
+        SensorManager.getRotationMatrixFromVector(rotationMatrix, event.values)
         remapForRotation(getDisplayRotation())
         SensorManager.getOrientation(rotationMatrix, orientationValues)
-        val azimuth = (orientationValues[0] * RAD2DEG).toFloat()
+        val azimuth = normalizeAzimuth((orientationValues[0] * RAD2DEG).toFloat())
         val pitch = (orientationValues[1] * RAD2DEG).toFloat()
-        val magneticAzimuth = (azimuth + 360f) % 360f
-
         if (!hasInitialReading) {
-            smoothAzimuth = magneticAzimuth
+            smoothAzimuth = azimuth
             smoothPitch = pitch
             hasInitialReading = true
         } else {
-            smoothAzimuth = lowPassAngle(smoothAzimuth, magneticAzimuth)
+            smoothAzimuth = lowPassAngle(smoothAzimuth, azimuth)
             smoothPitch = lowPass(smoothPitch, pitch)
         }
-
-        _orientation.value = Pair(
-            round(smoothAzimuth * 10) / 10,
-            round(smoothPitch * 10) / 10
-        )
+        _sensorData.value = Pair(round(smoothAzimuth * 10) / 10, round(smoothPitch * 10) / 10)
     }
 
-    /** Standard exponential low-pass filter. */
     private fun lowPass(previous: Float, current: Float): Float {
         return previous + SMOOTHING_FACTOR * (current - previous)
     }
@@ -135,9 +123,10 @@ class SensorsRepo(
      */
     private fun lowPassAngle(previous: Float, current: Float): Float {
         var delta = current - previous
-        // Normalise delta into the range (-180, 180]
         while (delta > 180f) delta -= 360f
         while (delta <= -180f) delta += 360f
-        return (previous + SMOOTHING_FACTOR * delta + 360f) % 360f
+        return normalizeAzimuth(previous + SMOOTHING_FACTOR * delta)
     }
+
+    private fun normalizeAzimuth(value: Float): Float = (value + 360f) % 360f
 }

core/data/src/main/java/com/rtbishop/look4sat/core/data/repository/SettingsRepo.kt

@@ -25,6 +25,7 @@ import androidx.core.location.LocationListenerCompat
 import androidx.core.location.LocationManagerCompat
 import com.rtbishop.look4sat.core.domain.model.DataSourcesSettings
 import com.rtbishop.look4sat.core.domain.model.DatabaseState
+import com.rtbishop.look4sat.core.domain.model.MapSource
 import com.rtbishop.look4sat.core.domain.model.OtherSettings
 import com.rtbishop.look4sat.core.domain.model.PassesSettings
 import com.rtbishop.look4sat.core.domain.model.RCSettings
@@ -82,6 +83,8 @@ class SettingsRepo(
     private val keyShouldSeeWarning = "shouldSeeWarning"
     private val keyShouldSeeWhatsNew = "shouldSeeWhatsNew_v$appVersionName"
     private val keySstvMode = "sstvMode"
+    private val keyMapSource = "mapSource"
+    private val keyTiandituKey = "tiandituKey"
     private val keyUseCustomTle = "useCustomTle"
     private val keyUseCustomTransceivers = "useCustomTransceivers"
     private val keyTleUrl = "tleUrl"
@@ -113,8 +116,8 @@ class SettingsRepo(
     }
 
     private fun getSelectedTypes(): List<String> {
-        val typesString = preferences.getString(keySelectedTypes, null)
-        if (typesString.isNullOrEmpty()) return listOf("Amateur")
+        val typesString = preferences.getString(keySelectedTypes, "Amateur")
+        if (typesString.isNullOrEmpty()) return emptyList()
         return typesString.split(separatorComma)
     }
     //endregion
@@ -335,6 +338,8 @@ class SettingsRepo(
                 putBoolean(keyShouldSeeWarning, new.shouldSeeWarning)
                 putBoolean(keyShouldSeeWhatsNew, new.shouldSeeWhatsNew)
                 putString(keySstvMode, new.sstvMode)
+                putString(keyMapSource, MapSource.normalize(new.mapSource))
+                putString(keyTiandituKey, new.tiandituKey)
             }
             new
         }
@@ -349,7 +354,9 @@ class SettingsRepo(
         stateOfNightMode = preferences.getBoolean(keyStateOfNightMode, false),
         shouldSeeWarning = preferences.getBoolean(keyShouldSeeWarning, true),
         shouldSeeWhatsNew = preferences.getBoolean(keyShouldSeeWhatsNew, true),
-        sstvMode = preferences.getString(keySstvMode, null) ?: "Auto"
+        sstvMode = preferences.getString(keySstvMode, null) ?: "Auto",
+        mapSource = MapSource.normalize(preferences.getString(keyMapSource, null) ?: MapSource.TIANDITU_VECTOR),
+        tiandituKey = preferences.getString(keyTiandituKey, null) ?: ""
     )
     //endregion
 

core/data/src/main/java/com/rtbishop/look4sat/core/data/source/LocalSource.kt

@@ -74,7 +74,6 @@ class LocalSource(private val look4SatDao: Look4SatDao) : ILocalSource {
     }
 
     override suspend fun insertRadios(radios: List<SatRadio>) {
-        look4SatDao.deleteRadios()
         look4SatDao.insertRadios(radios.toFrameworkRadios())
     }
 

core/data/src/main/java/com/rtbishop/look4sat/core/data/source/RemoteSource.kt

@@ -24,6 +24,7 @@ import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.withContext
 import okhttp3.OkHttpClient
 import okhttp3.Request
+import java.io.ByteArrayInputStream
 import java.io.InputStream
 
 class RemoteSource(
@@ -45,7 +46,10 @@ class RemoteSource(
     override suspend fun getNetworkStream(url: String): InputStream? = withContext(dispatcher) {
         try {
             val networkRequest = Request.Builder().url(url).build()
-            httpClient.newCall(networkRequest).execute().body.byteStream()
+            httpClient.newCall(networkRequest).execute().use { response ->
+                if (!response.isSuccessful) return@withContext null
+                ByteArrayInputStream(response.body.bytes())
+            }
         } catch (exception: Exception) {
             println("RemoteSource network stream exception: $exception")
             null

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/model/Settings.kt

@@ -57,9 +57,24 @@ data class OtherSettings(
     val stateOfNightMode: Boolean = false,
     val shouldSeeWarning: Boolean,
     val shouldSeeWhatsNew: Boolean,
-    val sstvMode: String = "Auto"
+    val sstvMode: String = "Auto",
+    val mapSource: String = MapSource.TIANDITU_VECTOR,
+    val tiandituKey: String = ""
 )
 
+object MapSource {
+    const val OSM = "osm"
+    const val TIANDITU = "tianditu"
+    const val TIANDITU_VECTOR = "tianditu_vector"
+    const val TIANDITU_IMAGE = "tianditu_image"
+
+    fun normalize(source: String): String = when (source) {
+        TIANDITU -> TIANDITU_VECTOR
+        OSM, TIANDITU_VECTOR, TIANDITU_IMAGE -> source
+        else -> TIANDITU_VECTOR
+    }
+}
+
 data class DataSourcesSettings(
     val useCustomTLE: Boolean,
     val useCustomTransceivers: Boolean,

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ISensorsRepo.kt

@@ -21,7 +21,7 @@ import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import kotlinx.coroutines.flow.StateFlow
 
 interface ISensorsRepo {
-    val orientation: StateFlow<Pair<Float, Float>>
+    val sensorData: StateFlow<Pair<Float, Float>>
     fun getMagDeclination(geoPos: GeoPos, time: Long = System.currentTimeMillis()): Float
     fun enableSensor()
     fun disableSensor()

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/sstv/SstvDecoder.kt

@@ -47,11 +47,12 @@ class SstvDecoder(
         onBufferOverflow = BufferOverflow.DROP_OLDEST
     )
     val frames: SharedFlow<SstvFrame> = _frames
-    val supportedModes: List<String> = buildList {
-        add("Raw"); add("HF Fax"); decoder.allModes.mapTo(this) { it.name }
-    }
+    val supportedModes: List<String> = decoder.allModes.map { it.name }
 
     suspend fun feedSamples(samples: FloatArray) = withContext(Dispatchers.Default) {
+        // Normalize to a fixed RMS before processing so that both direct audio
+        // coupling and air-coupled microphone input decode with equal reliability.
+        normalise(samples)
         val hasNewLines = decoder.process(samples, channelSelect)
         if (hasNewLines) emitFrame()
     }
@@ -64,12 +65,31 @@ class SstvDecoder(
     }
 
     private fun emitFrame() {
-        val imagePixels = if (imageBuffer.line > 0) imageBuffer.pixels.copyOf() else null
         val imageWidth = imageBuffer.width
         val imageHeight = imageBuffer.height
+        // Copy only the active image region — imageBuffer.pixels is pre-allocated
+        // at the maximum possible size (PD-290: 800×616), so we must not copyOf()
+        // the entire array and send padding pixels to the observer.
+        val imagePixels = if (imageBuffer.line > 0) imageBuffer.pixels.copyOf(imageWidth * imageHeight) else null
         val modeName = decoder.currentMode.name
         _frames.tryEmit(SstvFrame(imagePixels, imageWidth, imageHeight, modeName))
     }
+
+    // Target RMS level for the normalizer. 0.25 leaves headroom while keeping the
+    // FM demodulator well above its noise floor regardless of input gain.
+    private val targetRms = 0.25f
+
+    // Bring the buffer to a fixed RMS so that microphone and direct-coupled inputs
+    // both decode reliably. The guard prevents amplifying pure silence into noise.
+    private fun normalise(buffer: FloatArray) {
+        var sumSq = 0f
+        for (s in buffer) sumSq += s * s
+        val rms = sqrt(sumSq / buffer.size)
+        if (rms > 1e-6f) {
+            val gain = targetRms / rms
+            for (i in buffer.indices) buffer[i] *= gain
+        }
+    }
 }
 
 internal enum class SyncPulseWidth { FiveMs, NineMs, TwentyMs }
@@ -136,6 +156,10 @@ internal class SyncPulseDetector(sampleRate: Int) {
     fun process(buffer: FloatArray, channelSelect: Int): Boolean {
         var detected = false
         val channels = if (channelSelect > 0) 2 else 1
+        // NOTE: buffer[i] is overwritten in-place with the FM-demodulated frequency
+        // value for every mono sample (channelSelect == 0). DecoderEngine.process()
+        // reads back these values to populate scanLineBuffer. Callers must not reuse
+        // the buffer after this call.
         for (i in 0 until buffer.size / channels) {
             when (channelSelect) {
                 1 -> baseBand.set(buffer[2 * i])
@@ -200,7 +224,6 @@ internal class DecoderEngine(
     private val visBitLen: Int
     private val visLen: Int
     private val rawMode: SstvMode
-    private val hfFaxMode: SstvMode
     private val modes5ms: ArrayList<SstvMode>
     private val modes9ms: ArrayList<SstvMode>
     private val modes20ms: ArrayList<SstvMode>
@@ -217,6 +240,10 @@ internal class DecoderEngine(
 
     init {
         imageBuffer.line = -1
+        // Pre-allocate for the largest possible mode (PD-290: 800×616 = 492 800 ints)
+        // so that handleHeader/processPulse can reuse the array with a fill(0) instead
+        // of allocating a fresh IntArray on every new image, reducing GC pressure.
+        imageBuffer.pixels = IntArray(800 * 616)
         val pfLen = round(0.0025 * sampleRate).toInt() or 1
         pulseFilterDelay = (pfLen - 1) / 2
         pulseFilter = MovingAverage(pfLen)
@@ -231,7 +258,6 @@ internal class DecoderEngine(
         syncTolerance = round(0.03 * sampleRate).toInt()
         lineTolerance = round(0.001 * sampleRate).toInt()
         rawMode = RawMode(rawName, sampleRate)
-        hfFaxMode = HfFaxMode(sampleRate)
         val robot36 = Robot36Mode(sampleRate)
         currentMode = robot36
         curLineSamples = robot36.scanLineSamples
@@ -301,11 +327,7 @@ internal class DecoderEngine(
     }
 
     fun setMode(name: String) {
-        if (rawMode.name == name) {
-            lockMode = true; imageBuffer.line = -1; currentMode = rawMode; return
-        }
-        var mode = allModes.firstOrNull { it.name == name }
-        if (mode == null && hfFaxMode.name == name) mode = hfFaxMode
+        val mode = allModes.firstOrNull { it.name == name }
         if (mode == currentMode) {
             lockMode = true; return
         }
@@ -335,6 +357,10 @@ internal class DecoderEngine(
         return best
     }
 
+    // scopeBuffer is twice the display height. Each decoded scan line is written
+    // to both the current rolling position (top half, wraps at height/2) and the
+    // same row offset in the bottom half. The UI displays a window that always
+    // spans the half-height boundary, giving a seamless non-wrapping scroll effect.
     private fun copyUnscaled() {
         val w = minOf(scopeBuffer.width, pixelBuffer.width)
         for (row in 0 until pixelBuffer.height) {
@@ -424,6 +450,9 @@ internal class DecoderEngine(
         if ((amount <= 0) || (amount > sample)) return
         sample -= amount; leaderBreak -= amount; lastSync -= amount
         adjust(sync5ms, amount); adjust(sync9ms, amount); adjust(sync20ms, amount)
+        // Discard already-decoded samples by sliding the live region back to index 0.
+        // System.arraycopy handles the overlapping regions correctly and is a native
+        // memcpy on JVM, so this is fast despite moving the full remaining window.
         scanLineBuffer.copyInto(scanLineBuffer, 0, amount, amount + sample)
     }
 
@@ -494,7 +523,7 @@ internal class DecoderEngine(
         if (lockMode && mode != currentMode) return false
         mode.resetState()
         imageBuffer.width = mode.width; imageBuffer.height = mode.height
-        imageBuffer.pixels = IntArray(mode.width * mode.height); imageBuffer.line = 0
+        imageBuffer.pixels.fill(0, 0, mode.width * mode.height); imageBuffer.line = 0
         currentMode = mode
         lastSync = sIdx + mode.firstSyncPulseIndex; curLineSamples = mode.scanLineSamples; lastOffset = ldrOffset
         var oldest = lastSync - (pulses.size - 1) * curLineSamples
@@ -527,6 +556,15 @@ internal class DecoderEngine(
         var changed = false
         if (lockMode || imageBuffer.line in 0 until imageBuffer.height) {
             if (currentMode != rawMode && abs(lineSamples - currentMode.scanLineSamples) > lineTolerance) return false
+            // Try continuous decoding
+            if (lockMode && imageBuffer.line == -1 && currentMode != rawMode) {
+                currentMode.resetState()
+                imageBuffer.width = currentMode.width
+                imageBuffer.height = currentMode.height
+                imageBuffer.pixels.fill(0, 0, currentMode.width * currentMode.height)
+                imageBuffer.line = 0
+                drawLines(0xff000000.toInt(), 10); drawLines(0xffffff00.toInt(), 8); drawLines(0xff000000.toInt(), 10)
+            }
         } else {
             val prev = currentMode; currentMode = detectMode(modes, lineSamples)
             changed =

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/sstv/SstvDsp.kt

@@ -18,7 +18,6 @@
 package com.rtbishop.look4sat.core.domain.sstv
 
 import kotlin.math.PI
-import kotlin.math.atan2
 import kotlin.math.cos
 import kotlin.math.pow
 import kotlin.math.round
@@ -34,7 +33,6 @@ internal class Complex(var real: Float = 0f, var imag: Float = 0f) {
     fun set(real: Float): Complex = set(real, 0f)
 
     fun abs(): Float = sqrt(real * real + imag * imag)
-    fun arg(): Float = atan2(imag, real)
 
     fun mul(other: Complex): Complex {
         val tmp = real * other.real - imag * other.imag
@@ -74,21 +72,21 @@ internal object WindowFunctions {
     }
 }
 
+// O(1) ring buffer — simpler and faster than a segment tree for the short window
+// lengths used here (≤512 samples). Float32 accumulated drift over such windows
+// is ~6e-5, negligible for audio-frequency processing.
 internal open class MovingSum(val length: Int) {
-    private val tree = FloatArray(2 * length)
-    private var leaf = length
+    private val buf = FloatArray(length)
+    private var pos = 0
+    private var runningSum = 0f
 
     fun add(input: Float) {
-        tree[leaf] = input
-        var child = leaf
-        var parent = leaf / 2
-        while (parent > 0) {
-            tree[parent] = tree[child] + tree[child xor 1]; child = parent; parent /= 2
-        }
-        if (++leaf >= tree.size) leaf = length
+        runningSum += input - buf[pos]
+        buf[pos] = input
+        if (++pos >= length) pos = 0
     }
 
-    fun sum(): Float = tree[1]
+    fun sum(): Float = runningSum
     fun sum(input: Float): Float {
         add(input); return sum()
     }
@@ -134,8 +132,15 @@ internal class Phasor(freq: Double, rate: Double) {
         val omega = 2 * PI * freq / rate
         Complex(cos(omega).toFloat(), sin(omega).toFloat())
     }
+    private var count = 0
 
-    fun rotate(): Complex = value.div(value.mul(delta).abs())
+    // Renormalize every 512 rotations to prevent magnitude drift accumulation,
+    // eliminating the per-sample sqrt without sacrificing demodulation accuracy.
+    fun rotate(): Complex {
+        value.mul(delta)
+        if (++count == 512) { value.div(value.abs()); count = 0 }
+        return value
+    }
 }
 
 internal class FmDemodulator(bandwidth: Double, sampleRate: Double) {
@@ -145,11 +150,30 @@ internal class FmDemodulator(bandwidth: Double, sampleRate: Double) {
     private var prev = 0f
 
     fun demodulate(input: Complex): Float {
-        val phase = input.arg()
+        // Use fast polynomial atan2 instead of the exact trigonometric call.
+        // Max error ~0.005 rad translates to <1 Hz frequency error at 44100 Hz,
+        // well within the 50 Hz sync tolerance.
+        val phase = fastAtan2(input.imag, input.real)
         var delta = phase - prev; prev = phase
         if (delta < -pi) delta += twoPi else if (delta > pi) delta -= twoPi
         return scale * delta
     }
+
+    // Rajan's polynomial approximation of atan2 — avoids a transcendental call
+    // in the per-sample hot path (~44 k calls/s at 44100 Hz sample rate).
+    private fun fastAtan2(y: Float, x: Float): Float {
+        val absY = kotlin.math.abs(y) + 1e-10f
+        val r: Float
+        val angle: Float
+        if (x >= 0f) {
+            r = (x - absY) / (x + absY)
+            angle = 0.1963f * r * r * r - 0.9817f * r + pi / 4f
+        } else {
+            r = (x + absY) / (absY - x)
+            angle = 0.1963f * r * r * r - 0.9817f * r + 3f * pi / 4f
+        }
+        return if (y < 0f) -angle else angle
+    }
 }
 
 internal class ComplexFirFilter(val length: Int) {

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/sstv/SstvModes.kt

@@ -257,9 +257,16 @@ internal class Robot36Mode(sampleRate: Int) : SstvMode {
             val lPos = lumBegin + (i * lumSamples) / width
             val cPos = chromBegin + (i * chromSamples) / width
             if (even) {
+                // Even line: store Y in the red channel slot and Cr in the blue slot,
+                // using ColorConverter.rgb() as a convenient 3×byte packer (not RGB).
+                // The odd line will read these back and combine with its own Cb to
+                // produce the final YUV→RGB conversion for both rows.
                 pixelBuffer.pixels[i] = ColorConverter.rgb(scratch[lPos], 0f, scratch[cPos])
             } else {
                 val evenYuv = pixelBuffer.pixels[i]
+                // Even pixel packing: 0xAARRGGBB → Y=RR, Cb=GG(unused), Cr=BB
+                // Odd pixel:  Y=lPos, Cb=cPos, Cr=(borrowed from even's BB slot)
+                // Merge: take Y+Cr from even row (bits 0x00ff00ff) and Cb from odd (0x0000ff00).
                 val oddYuv = ColorConverter.rgb(scratch[lPos], scratch[cPos], 0f)
                 pixelBuffer.pixels[i] = ColorConverter.yuv2rgb((evenYuv and 0x00ff00ff) or (oddYuv and 0x0000ff00))
                 pixelBuffer.pixels[i + width] =
@@ -389,53 +396,6 @@ internal class PdMode(
     }
 }
 
-internal class HfFaxMode(private val sampleRate: Int) : SstvMode {
-    override val name = "HF Fax"
-    override val visCode = -1
-    override val width = 640
-    override val height = 1200
-    override val firstPixelSampleIndex = 0
-    override val firstSyncPulseIndex = -1
-    override val scanLineSamples get() = sampleRate / 2
-
-    private val ema = Ema()
-    private val cumulated = FloatArray(width)
-
-    var horizontalShift = 0; private set
-
-    override fun decodeScanLine(
-        pixelBuffer: PixelBuffer,
-        scratch: FloatArray,
-        scanLine: FloatArray,
-        scopeWidth: Int,
-        syncPulseIndex: Int,
-        lineSamples: Int,
-        freqOffset: Float
-    ): Boolean {
-        if (syncPulseIndex < 0 || syncPulseIndex + lineSamples > scanLine.size) return false
-        ema.setCutoff(width.toDouble(), (2 * lineSamples).toDouble(), 2); ema.reset()
-        for (i in 0 until lineSamples) scratch[i] = ema.process(scanLine[syncPulseIndex + i])
-        ema.reset()
-        for (i in lineSamples - 1 downTo 0) scratch[i] = freqToLevel(ema.process(scratch[i]), freqOffset)
-        var bestIdx = 0
-        var bestVal = 0f
-        for (i in 0 until width) {
-            val pos = (i * lineSamples) / width
-            val color = ColorConverter.gray(scratch[pos])
-            pixelBuffer.pixels[i] = color
-            // Grayscale: R==G==B, so luminance is simply the channel value normalized
-            val gray = (color and 0xFF) / 255f
-            cumulated[i] = cumulated[i] * 0.99f + gray * 0.01f
-            if (cumulated[i] > bestVal) {
-                bestIdx = i; bestVal = cumulated[i]
-            }
-        }
-        horizontalShift = bestIdx
-        pixelBuffer.width = width; pixelBuffer.height = 1
-        return true
-    }
-}
-
 internal class RawMode(override val name: String, sampleRate: Int) : SstvMode {
     override val visCode = -1
     override val width = -1

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/utility/GeoConverter.kt

@@ -17,7 +17,9 @@
  */
 package com.rtbishop.look4sat.core.domain.utility
 
+import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.DEG2RAD
+import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
 import com.rtbishop.look4sat.core.domain.predict.RAD2DEG
 import kotlin.math.acos
 import kotlin.math.atan2
@@ -85,6 +87,13 @@ fun clipLon(longitude: Double): Double {
     return clip(result, MIN_LONGITUDE, MAX_LONGITUDE)
 }
 
+fun OrbitalPos.toMapGeoPos(): GeoPos {
+    return GeoPos(
+        latitude = clipLat(latitude.toDegrees()),
+        longitude = clipLon(longitude.toDegrees())
+    )
+}
+
 private fun clip(currentValue: Double, minValue: Double, maxValue: Double): Double {
     return min(max(currentValue, minValue), maxValue)
 }

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/BubblesEffect.kt

@@ -0,0 +1,424 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.presentation
+
+import android.graphics.Paint
+import android.graphics.LinearGradient
+import android.graphics.RadialGradient
+import android.graphics.Shader
+import androidx.compose.foundation.Canvas
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.runtime.withFrameNanos
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.DrawScope
+import androidx.compose.ui.graphics.nativeCanvas
+import androidx.core.graphics.withRotation
+import kotlinx.coroutines.isActive
+import kotlin.math.atan2
+import kotlin.math.cos
+import kotlin.math.min
+import kotlin.math.sin
+import kotlin.math.sqrt
+import kotlin.random.Random
+
+@Immutable
+data class BubblesStyle(
+    val bgColor: Color = Color.Black,
+    val bubbleCount: Int = 16,
+    val minBubbleCount: Int = 8,
+    val maxBubbleCount: Int = 16,
+    val adaptiveBubbleCount: Boolean = true,
+    val spawnIntervalMs: Long = 800L,
+    val bubbleRadiusFraction: Float = 0.24f,
+    val adaptiveSizing: Boolean = true,
+    val referenceMinSizePx: Float = 360f,
+    val referenceAreaPx: Float = 360f * 800f,
+    val minBubbleRadiusPx: Float = 16f,
+    val maxBubbleRadiusPx: Float = 256f,
+    val speedScale: Float = 0.99f,
+    val minVelocity: Float = 0.8f,
+    val maxVelocity: Float = 3.2f,
+    val hueRotationSpeedDps: Float = 60f, // degrees per second
+)
+
+@Composable
+fun BubblesEffect(
+    modifier: Modifier = Modifier,
+    isRunning: Boolean = true,
+    style: BubblesStyle = BubblesStyle(),
+) {
+    val renderer = remember { BubblesRenderer() }
+    var frameSignal by remember { mutableIntStateOf(0) }
+
+    // Animation loop
+    LaunchedEffect(isRunning, style) {
+        if (!isRunning) return@LaunchedEffect
+        var previousNanos = 0L
+        while (isActive) {
+            withFrameNanos { now ->
+                if (previousNanos == 0L) previousNanos = now
+                val deltaSec = ((now - previousNanos).coerceAtMost(MAX_STEP_NANOS)).toFloat() / NANOS_TO_SECONDS
+                previousNanos = now
+                renderer.update(deltaSec, style)
+                frameSignal++
+            }
+        }
+    }
+    Canvas(modifier = modifier) {
+        frameSignal
+        renderer.ensureLayout(size)
+        renderer.draw(this, style)
+    }
+}
+
+private const val MAX_STEP_NANOS = 16_666_667L // ~60 FPS
+private const val NANOS_TO_SECONDS = 1_000_000_000f
+private val SHELL_GRADIENT_STOPS = floatArrayOf(0f, 0.52f, 0.66f, 0.79f, 0.90f, 0.968f, 0.993f, 1f)
+private val INNER_GRADIENT_STOPS = floatArrayOf(0f, 0.34f, 0.68f, 1f)
+
+private data class Velocity(var x: Float, var y: Float)
+
+private data class Bubble(
+    var x: Float,
+    var y: Float,
+    val radius: Float,
+    val velocity: Velocity,
+    val baseHue: Float, // 0-360, unique for each bubble
+)
+
+private class BubblesRenderer {
+    private var width = 0f
+    private var height = 0f
+    private val bubbles = mutableListOf<Bubble>()
+    private val random = Random(System.currentTimeMillis())
+    private var globalHueRotation = 0f // degrees, rotates all bubbles hues
+    private var spawnAccumulatorSec = 0f
+    private val paint = Paint(Paint.ANTI_ALIAS_FLAG)
+    private val shellColors = IntArray(8)
+    private val innerColors = IntArray(4)
+
+    fun ensureLayout(size: Size) {
+        val targetWidth = size.width
+        val targetHeight = size.height
+        if (targetWidth <= 0f || targetHeight <= 0f) return
+        val shouldRebuild = width != targetWidth || height != targetHeight
+        if (shouldRebuild) {
+            width = targetWidth
+            height = targetHeight
+            bubbles.clear()
+            spawnAccumulatorSec = 0f
+        }
+    }
+
+    fun spawnBubble(style: BubblesStyle): Boolean {
+        if (width <= 0f || height <= 0f) return false
+        val radius = resolveBubbleRadius(style)
+        val (velocityMin, velocityMax) = resolveVelocityRange(style)
+        val bubble = Bubble(
+            x = radius,
+            y = height - radius,
+            radius = radius,
+            velocity = Velocity(
+                x = randomInRange(velocityMin, velocityMax),
+                y = -randomInRange(velocityMin, velocityMax),
+            ),
+            baseHue = random.nextFloat() * 360f, // Random starting hue for this bubble
+        )
+        bubbles.add(bubble)
+        return true
+    }
+
+    fun update(deltaSeconds: Float, style: BubblesStyle) {
+        if (width <= 0f || height <= 0f) return
+
+        spawnMissingBubbles(deltaSeconds, style)
+
+        // Rotate hue for all bubbles
+        globalHueRotation += style.hueRotationSpeedDps * deltaSeconds
+        if (globalHueRotation >= 360f) globalHueRotation -= 360f
+        val frameScale = deltaSeconds * 60f
+        for (i in bubbles.indices) {
+            val bubble = bubbles[i]
+            // Update position
+            bubble.x += bubble.velocity.x * frameScale
+            bubble.y += bubble.velocity.y * frameScale
+            // Bounce off walls
+            if (bubble.x > width - bubble.radius) {
+                bubble.x = width - bubble.radius
+                bubble.velocity.x *= -1
+            }
+            if (bubble.x < bubble.radius) {
+                bubble.x = bubble.radius
+                bubble.velocity.x *= -1
+            }
+            if (bubble.y > height - bubble.radius) {
+                bubble.y = height - bubble.radius
+                bubble.velocity.y *= -1
+            }
+            if (bubble.y < bubble.radius) {
+                bubble.y = bubble.radius
+                bubble.velocity.y *= -1
+            }
+        }
+        // Collision detection and resolution
+        for (i in bubbles.indices) {
+            for (j in (i + 1) until bubbles.size) {
+                val b1 = bubbles[i]
+                val b2 = bubbles[j]
+                if (isCollided(b1, b2)) resolveCollision(b1, b2)
+            }
+        }
+    }
+
+    private fun spawnMissingBubbles(deltaSeconds: Float, style: BubblesStyle) {
+        val targetCount = resolveTargetBubbleCount(style)
+        if (bubbles.size >= targetCount) return
+
+        val spawnIntervalSec = style.spawnIntervalMs.coerceAtLeast(1L) / 1_000f
+        spawnAccumulatorSec += deltaSeconds
+
+        while (bubbles.size < targetCount && spawnAccumulatorSec >= spawnIntervalSec) {
+            if (!spawnBubble(style)) break
+            spawnAccumulatorSec -= spawnIntervalSec
+        }
+    }
+
+    fun draw(scope: DrawScope, style: BubblesStyle) {
+        if (width <= 0f || height <= 0f) return
+        scope.drawRect(style.bgColor)
+        val canvas = scope.drawContext.canvas.nativeCanvas
+        for (i in bubbles.indices) {
+            drawBubbleWithGradient(canvas, bubbles[i])
+        }
+    }
+
+    private fun drawBubbleWithGradient(canvas: android.graphics.Canvas, bubble: Bubble) {
+        val hue = (bubble.baseHue + globalHueRotation) % 360f
+        val lit = 53.33f + maxOf(0f, (70f - kotlin.math.abs(244f - hue)) / 4f)
+        val rgb = hueToRgb(hue, lit)
+        val shellColor = mixWithWhite(rgb, 0.04f)
+        val innerColor = mixWithWhite(rgb, 0.10f)
+        val shimmerColor = mixWithWhite(rgb, 0.35f)
+        // Outer shell
+        val shellGradient = RadialGradient(
+            bubble.x, bubble.y, bubble.radius,
+            buildShellColors(shellColor),
+            SHELL_GRADIENT_STOPS,
+            Shader.TileMode.CLAMP
+        )
+        paint.style = Paint.Style.FILL
+        paint.shader = shellGradient
+        canvas.drawCircle(bubble.x, bubble.y, bubble.radius, paint)
+        // Subtle thin rim
+        paint.shader = null
+        paint.style = Paint.Style.STROKE
+        paint.strokeWidth = maxOf(1f, bubble.radius * 0.024f)
+        paint.color = colorWithAlpha(mixWithWhite(shellColor, 0.08f), 0.30f)
+        canvas.drawCircle(bubble.x, bubble.y, bubble.radius - paint.strokeWidth * 0.5f, paint)
+        // Top internal bubble
+        val innerTop = bubble.y - bubble.radius * 0.96f
+        val innerBottom = bubble.y + bubble.radius * 0.48f
+        val innerLeft = bubble.x - bubble.radius * 0.84f
+        val innerRight = bubble.x + bubble.radius * 0.84f
+        val innerGradient = LinearGradient(
+            bubble.x,
+            innerTop,
+            bubble.x,
+            innerBottom,
+            buildInnerColors(innerColor),
+            INNER_GRADIENT_STOPS,
+            Shader.TileMode.CLAMP
+        )
+        paint.style = Paint.Style.FILL
+        paint.shader = innerGradient
+        canvas.drawOval(
+            innerLeft,
+            innerTop,
+            innerRight,
+            innerBottom,
+            paint
+        )
+        // Top-left shimmer
+        paint.shader = null
+        paint.style = Paint.Style.FILL
+        paint.color = colorWithAlpha(shimmerColor, 0.95f)
+        val shimmerCx = bubble.x - bubble.radius * 0.40f
+        val shimmerCy = bubble.y - bubble.radius * 0.72f
+        val shimmerHalfWidth = bubble.radius * 0.06f
+        val shimmerHalfHeight = bubble.radius * 0.21f
+        canvas.withRotation(60f, shimmerCx, shimmerCy) {
+            drawOval(
+                shimmerCx - shimmerHalfWidth,
+                shimmerCy - shimmerHalfHeight,
+                shimmerCx + shimmerHalfWidth,
+                shimmerCy + shimmerHalfHeight,
+                paint
+            )
+        }
+    }
+
+    private fun isCollided(bubble1: Bubble, bubble2: Bubble): Boolean {
+        val dx = bubble1.x - bubble2.x
+        val dy = bubble1.y - bubble2.y
+        val radius = (bubble1.radius + bubble2.radius) * 0.9f
+        return dx * dx + dy * dy < radius * radius
+    }
+
+    private fun resolveCollision(particle: Bubble, otherParticle: Bubble) {
+        val xVelocityDiff = particle.velocity.x - otherParticle.velocity.x
+        val yVelocityDiff = particle.velocity.y - otherParticle.velocity.y
+        val xDist = otherParticle.x - particle.x
+        val yDist = otherParticle.y - particle.y
+        // Prevent accidental overlap
+        if (xVelocityDiff * xDist + yVelocityDiff * yDist >= 0) {
+            val angle = -atan2(otherParticle.y - particle.y, otherParticle.x - particle.x)
+            val m1 = 1f
+            val m2 = 1f
+            val u1 = rotate(particle.velocity, angle)
+            val u2 = rotate(otherParticle.velocity, angle)
+            val v1 = Velocity(
+                x = (u1.x * (m1 - m2)) / (m1 + m2) + (u2.x * 2 * m2) / (m1 + m2),
+                y = u1.y,
+            )
+            val v2 = Velocity(
+                x = (u2.x * (m1 - m2)) / (m1 + m2) + (u1.x * 2 * m2) / (m1 + m2),
+                y = u2.y,
+            )
+            val vFinal1 = rotate(v1, -angle)
+            val vFinal2 = rotate(v2, -angle)
+            particle.velocity.x = vFinal1.x
+            particle.velocity.y = vFinal1.y
+            otherParticle.velocity.x = vFinal2.x
+            otherParticle.velocity.y = vFinal2.y
+        }
+    }
+
+    private fun rotate(velocity: Velocity, angle: Float): Velocity {
+        return Velocity(
+            x = velocity.x * cos(angle) - velocity.y * sin(angle),
+            y = velocity.x * sin(angle) + velocity.y * cos(angle),
+        )
+    }
+
+    private fun buildShellColors(shellColor: Int): IntArray {
+        shellColors[0] = colorWithAlpha(shellColor, 0f)
+        shellColors[1] = colorWithAlpha(shellColor, 0f)
+        shellColors[2] = colorWithAlpha(shellColor, 0.04f)
+        shellColors[3] = colorWithAlpha(shellColor, 0.12f)
+        shellColors[4] = colorWithAlpha(shellColor, 0.28f)
+        shellColors[5] = colorWithAlpha(shellColor, 0.44f)
+        shellColors[6] = colorWithAlpha(shellColor, 0.58f)
+        shellColors[7] = colorWithAlpha(shellColor, 0.64f)
+        return shellColors
+    }
+
+    private fun buildInnerColors(innerColor: Int): IntArray {
+        innerColors[0] = colorWithAlpha(innerColor, 0.48f)
+        innerColors[1] = colorWithAlpha(innerColor, 0.36f)
+        innerColors[2] = colorWithAlpha(innerColor, 0.08f)
+        innerColors[3] = colorWithAlpha(innerColor, 0f)
+        return innerColors
+    }
+
+    private fun resolveBubbleRadius(style: BubblesStyle): Float {
+        val minDimension = min(width, height)
+        val baseRadius = minDimension * style.bubbleRadiusFraction
+        val minRadius = style.minBubbleRadiusPx.coerceAtLeast(1f)
+        val maxRadius = maxOf(minRadius, style.maxBubbleRadiusPx)
+        if (!style.adaptiveSizing || minDimension <= 0f) {
+            return baseRadius.coerceIn(minRadius, maxRadius)
+        }
+
+        val reference = style.referenceMinSizePx.coerceAtLeast(1f)
+        val dampening = sqrt((reference / minDimension).coerceAtMost(1f))
+        return (baseRadius * dampening).coerceIn(minRadius, maxRadius)
+    }
+
+    private fun resolveTargetBubbleCount(style: BubblesStyle): Int {
+        val baseCount = style.bubbleCount.coerceAtLeast(1)
+        if (!style.adaptiveBubbleCount) return baseCount
+
+        val area = width * height
+        val referenceArea = style.referenceAreaPx.coerceAtLeast(1f)
+        val areaScale = sqrt((area / referenceArea).coerceAtLeast(0.25f))
+        val scaledCount = (baseCount * areaScale).toInt()
+        val minCount = style.minBubbleCount.coerceAtLeast(1)
+        val maxCount = maxOf(minCount, style.maxBubbleCount.coerceAtLeast(1))
+        return scaledCount.coerceIn(minCount, maxCount)
+    }
+
+    private fun resolveVelocityRange(style: BubblesStyle): Pair<Float, Float> {
+        val referenceMaxVelocity = maxOf(height / 300f, 1f)
+        val velocityMin = (style.minVelocity * style.speedScale).coerceAtLeast(0.05f)
+        val velocityMax = maxOf(velocityMin, min(style.maxVelocity, referenceMaxVelocity) * style.speedScale)
+        return velocityMin to velocityMax
+    }
+
+    private fun randomInRange(min: Float, max: Float): Float {
+        return random.nextFloat() * (max - min) + min
+    }
+}
+
+private fun hueToRgb(h: Float, l: Float): Int {
+    val hNorm = h / 360f
+    val lNorm = l / 100f
+    val sNorm = 1f
+    val c = (1f - kotlin.math.abs(2f * lNorm - 1f)) * sNorm
+    val hp = hNorm * 6f
+    val x = c * (1f - kotlin.math.abs((hp % 2f) - 1f))
+    val m = lNorm - c / 2f
+    val (r, g, b) = when {
+        hp < 1f -> Triple(c, x, 0f)
+        hp < 2f -> Triple(x, c, 0f)
+        hp < 3f -> Triple(0f, c, x)
+        hp < 4f -> Triple(0f, x, c)
+        hp < 5f -> Triple(x, 0f, c)
+        else -> Triple(c, 0f, x)
+    }
+    val r8 = ((r + m) * 255).toInt().coerceIn(0, 255)
+    val g8 = ((g + m) * 255).toInt().coerceIn(0, 255)
+    val b8 = ((b + m) * 255).toInt().coerceIn(0, 255)
+    return (0xFF shl 24) or (r8 shl 16) or (g8 shl 8) or b8
+}
+
+private fun colorWithAlpha(color: Int, alpha: Float): Int {
+    val a = (alpha * 255).toInt().coerceIn(0, 255)
+    val r = (color shr 16) and 0xFF
+    val g = (color shr 8) and 0xFF
+    val b = color and 0xFF
+    return (a shl 24) or (r shl 16) or (g shl 8) or b
+}
+
+private fun mixWithWhite(color: Int, amount: Float): Int {
+    val t = amount.coerceIn(0f, 1f)
+    val r = (color shr 16) and 0xFF
+    val g = (color shr 8) and 0xFF
+    val b = color and 0xFF
+    val mixedR = (r + (255 - r) * t).toInt().coerceIn(0, 255)
+    val mixedG = (g + (255 - g) * t).toInt().coerceIn(0, 255)
+    val mixedB = (b + (255 - b) * t).toInt().coerceIn(0, 255)
+    return (0xFF shl 24) or (mixedR shl 16) or (mixedG shl 8) or mixedB
+}

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/Components.kt

@@ -40,6 +40,7 @@ import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.ElevatedButton
 import androidx.compose.material3.ElevatedCard
 import androidx.compose.material3.Icon
+import androidx.compose.material3.LocalTextStyle
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
@@ -49,12 +50,21 @@ import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.Stroke
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.hideFromAccessibility
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.TextLayoutResult
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.text.font.FontStyle
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextDecoration
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.TextUnit
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.compose.ui.window.Dialog
@@ -387,3 +397,76 @@ fun elevationColor(elevation: Double): Color {
         else -> Color(0xFF66BB6A) // soft green for high elevation
     }
 }
+
+@Composable
+fun OutlinedText(
+    text: String,
+    modifier: Modifier = Modifier,
+    fillColor: Color = Color.Unspecified,
+    outlineColor: Color,
+    fontSize: TextUnit = TextUnit.Unspecified,
+    fontStyle: FontStyle? = null,
+    fontWeight: FontWeight? = null,
+    fontFamily: FontFamily? = null,
+    letterSpacing: TextUnit = TextUnit.Unspecified,
+    textDecoration: TextDecoration? = null,
+    textAlign: TextAlign? = null,
+    lineHeight: TextUnit = TextUnit.Unspecified,
+    overflow: TextOverflow = TextOverflow.Clip,
+    softWrap: Boolean = true,
+    maxLines: Int = Int.MAX_VALUE,
+    minLines: Int = 1,
+    onTextLayout: (TextLayoutResult) -> Unit = {},
+    style: TextStyle = LocalTextStyle.current,
+    outlineDrawStyle: Stroke = Stroke(width = 8f),
+) {
+    Box(modifier = modifier) {
+        Text(
+            text = text,
+            modifier = Modifier.semantics { hideFromAccessibility() },
+            color = outlineColor,
+            fontSize = fontSize,
+            fontStyle = fontStyle,
+            fontWeight = fontWeight,
+            fontFamily = fontFamily,
+            letterSpacing = letterSpacing,
+            textDecoration = null,
+            textAlign = textAlign,
+            lineHeight = lineHeight,
+            overflow = overflow,
+            softWrap = softWrap,
+            maxLines = maxLines,
+            minLines = minLines,
+            onTextLayout = onTextLayout,
+            style = style.copy(shadow = null, drawStyle = outlineDrawStyle),
+        )
+
+        Text(
+            text = text,
+            color = fillColor,
+            fontSize = fontSize,
+            fontStyle = fontStyle,
+            fontWeight = fontWeight,
+            fontFamily = fontFamily,
+            letterSpacing = letterSpacing,
+            textDecoration = textDecoration,
+            textAlign = textAlign,
+            lineHeight = lineHeight,
+            overflow = overflow,
+            softWrap = softWrap,
+            maxLines = maxLines,
+            minLines = minLines,
+            onTextLayout = onTextLayout,
+            style = style,
+        )
+    }
+}
+
+// Formats a frequency in Hz as "MMM.KKK.HHH" (e.g. 145.825.000) or "---"
+fun formatFrequency(frequencyHz: Long): String {
+    if (frequencyHz <= 0) return "---"
+    val mhz = frequencyHz / 1_000_000
+    val khz = (frequencyHz % 1_000_000) / 1_000
+    val hz = frequencyHz % 1_000
+    return String.format(Locale.ENGLISH, "%d.%03d.%03d", mhz, khz, hz)
+}

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/MatrixEffect.kt

@@ -0,0 +1,260 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.presentation
+
+import android.graphics.Paint
+import android.graphics.Typeface
+import androidx.compose.foundation.Canvas
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.runtime.withFrameNanos
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.nativeCanvas
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.unit.TextUnit
+import androidx.compose.ui.unit.sp
+import kotlinx.coroutines.isActive
+import kotlin.math.floor
+import kotlin.math.max
+import kotlin.math.min
+import kotlin.random.Random
+
+@Immutable
+data class MatrixStyle(
+    val bgColor: Color = Color.Black,
+    val bodyColor: Color = Color(0xFF29C94A),
+    val headColor: Color = Color(0xFFC2FFC6),
+    val tailAlphaFloor: Float = 0.14f, // 0.14f - 0.18f,
+    val fontSize: TextUnit = 14.sp, // 11.sp - 14.sp
+    val minStreamLength: Int = 8, // 6 - 8
+    val maxStreamLength: Int = 28,  // 20 - 28
+    val minSpeedRps: Float = 10f, // 10f - 15f
+    val maxSpeedRps: Float = 38f, // 38f - 45f
+    val resetPauseSec: ClosedFloatingPointRange<Float> = 0.1f..1.0f,
+)
+
+@Composable
+fun MatrixEffect(
+    modifier: Modifier = Modifier,
+    isRunning: Boolean = true,
+    style: MatrixStyle = MatrixStyle(),
+    symbols: String = DEFAULT_SYMBOLS,
+) {
+    val density = LocalDensity.current
+    val renderer = remember { MatrixRenderer() }
+    var frameSignal by remember { mutableIntStateOf(0) }
+
+    LaunchedEffect(isRunning, style, symbols) {
+        if (!isRunning) return@LaunchedEffect
+
+        var previousNanos = 0L
+        while (isActive) {
+            withFrameNanos { now ->
+                if (previousNanos == 0L) previousNanos = now
+                val deltaSec = ((now - previousNanos).coerceAtMost(MAX_STEP_NANOS)).toFloat() / NANOS_TO_SECONDS
+                previousNanos = now
+                renderer.update(deltaSec, style)
+                frameSignal++
+            }
+        }
+    }
+
+    Canvas(modifier = modifier) {
+        frameSignal
+        renderer.ensureLayout(size, density.density, style, symbols)
+        renderer.draw(this, style)
+    }
+}
+
+private const val MAX_STEP_NANOS = 33_333_333L
+private const val NANOS_TO_SECONDS = 1_000_000_000f
+private const val DEFAULT_SYMBOLS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789<>=*+-~:;/[]{}()"
+
+private fun Color.toArgb(): Int {
+    val a = (alpha.coerceIn(0f, 1f) * 255f + 0.5f).toInt()
+    val r = (red.coerceIn(0f, 1f) * 255f + 0.5f).toInt()
+    val g = (green.coerceIn(0f, 1f) * 255f + 0.5f).toInt()
+    val b = (blue.coerceIn(0f, 1f) * 255f + 0.5f).toInt()
+    return (a shl 24) or (r shl 16) or (g shl 8) or b
+}
+
+private class MatrixRenderer {
+    private var columns = 0
+    private var rows = 0
+    private var width = 0f
+    private var height = 0f
+    private var fontSizePx = 0f
+    private var charWidth = 0f
+    private var charHeight = 0f
+    private var baselineOffset = 0f
+    private var symbolSet = ""
+    private var symbols = charArrayOf()
+
+    private var glyphs = charArrayOf()
+    private var streams = emptyArray<StreamState>()
+
+    private val bodyPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply { typeface = Typeface.MONOSPACE }
+    private val headPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply { typeface = Typeface.MONOSPACE }
+    private val charBuffer = CharArray(1)
+    private val random = Random(System.currentTimeMillis())
+
+    fun ensureLayout(size: Size, density: Float, style: MatrixStyle, symbols: String) {
+        val targetFontPx = style.fontSize.value * density
+        val targetWidth = size.width
+        val targetHeight = size.height
+        val targetSymbols = symbols.ifBlank { DEFAULT_SYMBOLS }
+
+        if (targetWidth <= 0f || targetHeight <= 0f) return
+
+        val shouldRebuild = width != targetWidth ||
+            height != targetHeight ||
+            fontSizePx != targetFontPx ||
+            symbolSet != targetSymbols
+
+        if (!shouldRebuild) return
+
+        width = targetWidth
+        height = targetHeight
+        fontSizePx = targetFontPx
+        symbolSet = targetSymbols
+        this.symbols = targetSymbols.toCharArray()
+
+        bodyPaint.textSize = targetFontPx
+        headPaint.textSize = targetFontPx
+        charWidth = max(bodyPaint.measureText("W"), 1f)
+        val metrics = bodyPaint.fontMetrics
+        charHeight = max(metrics.descent - metrics.ascent, 1f)
+        baselineOffset = -metrics.ascent
+
+        columns = max((width / charWidth).toInt(), 1)
+        rows = max((height / charHeight).toInt() + 2, 1)
+
+        glyphs = CharArray(columns * rows) { randomGlyph() }
+        streams = Array(columns) { StreamState.random(rows, style, random) }
+    }
+
+    fun update(deltaSeconds: Float, style: MatrixStyle) {
+        if (columns == 0 || rows == 0 || deltaSeconds <= 0f) return
+
+        for (column in streams.indices) {
+            val stream = streams[column]
+            stream.pauseSec -= deltaSeconds
+            if (stream.pauseSec > 0f) continue
+
+            val previousHead = floor(stream.headRow).toInt()
+            stream.headRow += stream.speedRps * deltaSeconds
+            val newHead = floor(stream.headRow).toInt()
+
+            if (newHead > previousHead) {
+                for (row in (previousHead + 1)..newHead) {
+                    if (row in 0 until rows) {
+                        glyphs[row * columns + column] = randomGlyph()
+                    }
+                }
+            }
+
+            if (newHead - stream.length > rows) {
+                stream.reset(rows, style, random)
+            }
+        }
+    }
+
+    fun draw(scope: androidx.compose.ui.graphics.drawscope.DrawScope, style: MatrixStyle) {
+        if (columns == 0 || rows == 0) return
+
+        scope.drawRect(style.bgColor)
+
+        bodyPaint.color = style.bodyColor.toArgb()
+        headPaint.color = style.headColor.toArgb()
+        val tailAlphaFloor = style.tailAlphaFloor.coerceIn(0f, 1f)
+
+        val canvas = scope.drawContext.canvas.nativeCanvas
+        for (column in streams.indices) {
+            val stream = streams[column]
+            if (stream.pauseSec > 0f) continue
+
+            val head = floor(stream.headRow).toInt()
+            val startRow = max(0, head - stream.length + 1)
+            val endRow = min(rows - 1, head)
+            if (startRow > endRow) continue
+
+            for (row in endRow downTo startRow) {
+                val tailIndex = head - row
+
+                val paint = if (tailIndex == 0) headPaint else bodyPaint
+                if (tailIndex != 0) {
+                    val normalized = ((stream.length - tailIndex).toFloat() / stream.length).coerceIn(0f, 1f)
+                    val alpha = tailAlphaFloor + (1f - tailAlphaFloor) * normalized
+                    paint.alpha = (alpha * 255).toInt()
+                } else {
+                    paint.alpha = 255
+                }
+
+                val glyph = glyphs[row * columns + column]
+                charBuffer[0] = glyph
+                val x = column * charWidth
+                val y = row * charHeight + baselineOffset
+                canvas.drawText(charBuffer, 0, 1, x, y, paint)
+            }
+        }
+    }
+
+    private fun randomGlyph(): Char = symbols[random.nextInt(symbols.size)]
+}
+
+private data class StreamState(
+    var headRow: Float,
+    var length: Int,
+    var speedRps: Float,
+    var pauseSec: Float,
+) {
+    fun reset(rows: Int, style: MatrixStyle, random: Random) {
+        val randomOffset = random.nextFloat() * rows
+        headRow = -randomOffset
+        length = random.nextInt(
+            from = style.minStreamLength.coerceAtLeast(2),
+            until = (style.maxStreamLength.coerceAtLeast(style.minStreamLength + 1) + 1),
+        )
+        speedRps = random.nextFloat() * (style.maxSpeedRps - style.minSpeedRps) + style.minSpeedRps
+        pauseSec = random.nextFloat() * (style.resetPauseSec.endInclusive - style.resetPauseSec.start) +
+            style.resetPauseSec.start
+    }
+
+    companion object {
+        fun random(rows: Int, style: MatrixStyle, random: Random): StreamState {
+            val length = random.nextInt(
+                from = style.minStreamLength.coerceAtLeast(2),
+                until = (style.maxStreamLength.coerceAtLeast(style.minStreamLength + 1) + 1),
+            )
+            return StreamState(
+                headRow = -random.nextFloat() * rows,
+                length = length,
+                speedRps = random.nextFloat() * (style.maxSpeedRps - style.minSpeedRps) + style.minSpeedRps,
+                pauseSec = random.nextFloat() * (style.resetPauseSec.endInclusive - style.resetPauseSec.start) +
+                    style.resetPauseSec.start,
+            )
+        }
+    }
+}

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/Navigation.kt

@@ -38,3 +38,33 @@ sealed class Screen(val iconResId: Int, val titleResId: Int) : NavKey {
     @Serializable
     data object Settings : Screen(R.drawable.ic_settings, R.string.nav_prefs)
 }
+
+@Serializable
+data object RadarDestination : NavKey
+
+interface IDeeplinkMatcher {
+    fun match(deeplink: String): NavKey?
+}
+
+object PassDetailsMatcher : IDeeplinkMatcher {
+    val passDetailsRegex = """https://github.com/rt-bishop/Look4Sat/passes/(.*)""".toRegex()
+
+    override fun match(deeplink: String): NavKey? {
+        val passMatch = passDetailsRegex.find(deeplink)
+        passMatch?.let { match ->
+            val passId = match.groupValues[1]
+            if (passId.isNotEmpty()) return RadarDestination
+        }
+        return null
+    }
+}
+
+class DeeplinkResolver(private val fallbackDestination: NavKey = Screen.Passes) {
+
+    private val matchers: List<IDeeplinkMatcher> = listOf(PassDetailsMatcher)
+
+    fun resolve(deeplink: String): NavKey {
+        matchers.forEach { it.match(deeplink)?.let { match -> return match } }
+        return fallbackDestination
+    }
+}

core/presentation/src/main/res/values-es/strings.xml

@@ -38,7 +38,7 @@
     <string name="pass_empty_list_message">
         Asegúrate de que tus filtros sean correctos y hayas seleccionado satélites</string>
     <string name="pass_error_message">No hay pases de satélite próximos para mostrar</string>
-    <string name="pass_welcome_title">Bienvenido a Look4Sat\!</string>
+    <string name="pass_welcome_title">Bienvenido a Look4Sat-CNMap\!</string>
     <string name="pass_welcome_message">
         Asegúrate de configurar tu posición mediante GPS, Latitud/Longitud o QTH en Configuración.
         \n\nActualiza la base de datos al menos una vez por semana para obtener predicciones precisas.</string>
@@ -132,6 +132,7 @@
     <string name="prefs_bt_frequency_device_hint">Id dispositivo</string>
     <string name="prefs_bt_frequency_output_hint">Formato de datos</string>
     <string name="prefs_bt_perm_error">Revisa los permisos de Bluetooth</string>
+    <string name="prefs_net_perm_error">Revisa los permisos de red</string>
 
     <string name="prefs_other_title">Otros ajustes</string>
     <string name="prefs_other_switch_utc">Mostrar tiempos de pase en UTC</string>

core/presentation/src/main/res/values-ru/strings.xml

@@ -37,7 +37,7 @@
     <string name="pass_empty_list_message">
         Убедитесь, что ваши фильтры настроены правильно и вы выбрали спутники</string>
     <string name="pass_error_message">Нет предстоящих пролётов спутников</string>
-    <string name="pass_welcome_title">Добро пожаловать в Look4Sat\!</string>
+    <string name="pass_welcome_title">Добро пожаловать в Look4Sat-CNMap\!</string>
     <string name="pass_welcome_message">
         Обязательно укажите свое местоположение по GPS, широте/долготе или QTH в настройках.
         \n\nПожалуйста, обновляйте базу данных как минимум раз в неделю, чтобы получать точные прогнозы.</string>
@@ -131,6 +131,7 @@
     <string name="prefs_bt_frequency_device_hint">Id устройства</string>
     <string name="prefs_bt_frequency_output_hint">Формат</string>
     <string name="prefs_bt_perm_error">Нет разрешения использовать bluetooth</string>
+    <string name="prefs_net_perm_error">Нет разрешения использовать сеть</string>
 
     <string name="prefs_other_title">Другие настройки</string>
     <string name="prefs_other_switch_utc">Показывать время по UTC</string>

core/presentation/src/main/res/values-si/strings.xml

@@ -38,7 +38,7 @@
     <string name="pass_empty_list_message">
         ඔබගේ පෙරහන් නිවැරදි බවත් ඔබ චන්ද්‍රිකා තෝරාගෙන ඇති බවත් සහතික කර ගන්න</string>
     <string name="pass_error_message">ප්‍රදර්ශනය කිරීමට ඉදිරියට එන චන්ද්‍රිකා පසුකර යෑම් නැත.</string>
-    <string name="pass_welcome_title">Look4Sat වෙත සාදරයෙන් පිළිගනිමු\!</string>
+    <string name="pass_welcome_title">Look4Sat-CNMap වෙත සාදරයෙන් පිළිගනිමු\!</string>
     <string name="pass_welcome_message">
         සැකසුම් තුළ GPS, Lat/Lon හෝ QTH හරහා ඔබේ ස්ථානය සැකසීමට වග බලා ගන්න.
         \n\nනිවැරදි අනාවැකි ලබා ගැනීම සඳහා අවම වශයෙන් සතිපතා දත්ත සමුදාය යාවත්කාලීන කරන්න.</string>
@@ -132,6 +132,7 @@
     <string name="prefs_bt_frequency_device_hint">උපාංග id</string>
     <string name="prefs_bt_frequency_output_hint">දත්ත අකාරය</string>
     <string name="prefs_bt_perm_error">Bluetooth අවසර පරික්‍ෂා ක°</string>
+    <string name="prefs_net_perm_error">Network අවසර පරික්‍ෂා කරන්න</string>
 
     <string name="prefs_other_title">වෙනත් සැකසුම්</string>
     <string name="prefs_other_switch_utc">පසුකර වේලාවන් UTC මගින්</string>

core/presentation/src/main/res/values-tr/strings.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <!-- Commmon -->
-    <string name="app_name" translatable="false">Look4Sat</string>
+    <string name="app_name" translatable="false">Look4Sat-CNMap</string>
     <string name="btn_accept">Kabul et</string>
     <string name="btn_cancel">İptal</string>
     <string name="empty_list_message">Gösterilecek veri bulunamadı</string>
@@ -42,11 +42,11 @@
     <string name="pass_empty_list_message">
         Filtrelerinizin doğru olduğundan ve uydu seçtiğinizden emin olun</string>
     <string name="pass_error_message">Gösterilecek yaklaşan uydu geçişi bulunmuyor</string>
-    <string name="pass_welcome_title">Look4Sat\'a hoş geldiniz\!</string>
+    <string name="pass_welcome_title">Look4Sat-CNMap\'a hoş geldiniz\!</string>
     <string name="pass_welcome_message">
         Ayarlar\'dan GPS, Enlem/Boylam veya QTH kullanarak konumunuzu belirlediğinizden emin olun.
         \n\nDoğru tahminler alabilmek için veritabanını en az haftada bir güncelleyin.</string>
-    <string name="pass_whatsnew_title" translatable="false">What\'s new in Look4Sat</string>
+    <string name="pass_whatsnew_title" translatable="false">What\'s new in Look4Sat-CNMap</string>
     <string name="pass_whatsnew_message" translatable="false">
         * Switched to short-form commands in NetworkReporter, by theojalba
         \n* Added CAT radio control for full-duplex SAT operation, by jcmerg
@@ -84,7 +84,8 @@
     <!-- Map screen -->
     <string name="map_prev">Önceki</string>
     <string name="map_next">Sonraki</string>
-    <string name="map_copyright" translatable="false">© OpenStreetMap contributors</string>
+    <string name="map_copyright_osm" translatable="false">© OpenStreetMap contributors</string>
+    <string name="map_copyright_tianditu" translatable="false">© Tianditu</string>
     <string name="map_azimuth">Azimut: %.1f°</string>
     <string name="map_elevation">Yükseklik açısı: %.1f°</string>
     <string name="map_altitude">İrtifa: %.0f km</string>
@@ -100,12 +101,12 @@
     <string name="map_visible">Görünür</string>
 
     <!-- Settings screen -->
-    <string name="prefs_app_title" translatable="false">Look4Sat v%s</string>
-    <string name="prefs_app_url" translatable="false">https://play.google.com/store/apps/details?id=com.rtbishop.look4sat</string>
+    <string name="prefs_app_title" translatable="false">Look4Sat-CNMap v%s</string>
+    <string name="prefs_app_url" translatable="false">https://play.google.com/store/apps/details?id=cn.bh2vsq.look4sat</string>
     <string name="prefs_donate_title">Bağış yap</string>
     <string name="prefs_donate_url" translatable="false">https://ko-fi.com/rt_bishop</string>
     <string name="prefs_fdroid_title" translatable="false">F-Droid</string>
-    <string name="prefs_fdroid_url" translatable="false">https://f-droid.org/en/packages/com.rtbishop.look4sat/</string>
+    <string name="prefs_fdroid_url" translatable="false">https://f-droid.org/en/packages/cn.bh2vsq.look4sat/</string>
     <string name="prefs_github_title" translatable="false">GitHub</string>
     <string name="prefs_github_url" translatable="false">https://github.com/rt-bishop/Look4Sat/</string>
     <string name="prefs_license_title" translatable="false">GPLv3</string>
@@ -175,6 +176,7 @@
     <string name="prefs_bt_frequency_device_hint">Cihaz kimliği</string>
     <string name="prefs_bt_frequency_output_hint">Veri biçimi</string>
     <string name="prefs_bt_perm_error">Bluetooth izninizi kontrol edin</string>
+    <string name="prefs_net_perm_error">Ağ izninizi kontrol edin</string>
 
     <string name="prefs_other_title">Diğer ayarlar</string>
     <string name="prefs_other_switch_utc">Geçiş saatini UTC olarak göster</string>

core/presentation/src/main/res/values-uk/strings.xml

@@ -38,7 +38,7 @@
     <string name="pass_empty_list_message">
         Переконайтеся, що ваші фільтри правильні, і ви вибрали супутники</string>
     <string name="pass_error_message">Немає майбутніх прольотів супутників</string>
-    <string name="pass_welcome_title">Ласкаво просимо до Look4Sat\!</string>
+    <string name="pass_welcome_title">Ласкаво просимо до Look4Sat-CNMap\!</string>
     <string name="pass_welcome_message">
         Обов’язково встановіть своє місцезнаходження за допомогою GPS, широти/довготи або QTH у налаштуваннях.
         \n\nБудь ласка, оновлюйте базу даних принаймні раз на тиждень, щоб отримувати точні прогнози.</string>
@@ -132,6 +132,7 @@
     <string name="prefs_bt_frequency_device_hint">Id пристрою</string>
     <string name="prefs_bt_frequency_output_hint">Формат даних</string>
     <string name="prefs_bt_perm_error">Перевірте дозвіл Bluetooth</string>
+    <string name="prefs_net_perm_error">Перевірте дозвіл мережі</string>
 
     <string name="prefs_other_title">Інші налаштування</string>
     <string name="prefs_other_switch_utc">Показувати час в UTC</string>

core/presentation/src/main/res/values-zh/strings.xml

@@ -32,7 +32,7 @@
     <string name="pass_altitude">高度：%d km</string>
     <string name="pass_empty_list_message">请确保您的过滤器设置正确，并且已选择卫星</string>
     <string name="pass_error_message">没有即将过境的卫星</string>
-    <string name="pass_welcome_title">欢迎来到 Look4Sat\!</string>
+    <string name="pass_welcome_title">欢迎来到 Look4Sat-CNMap\!</string>
     <string name="pass_welcome_message">请务必在设置中通过GPS、经纬度或QTH定位您的位置\n建议至少每周更新一次数据库，以确保预测结果的准确性</string>
 
     <!-- Radar screen -->
@@ -124,6 +124,7 @@
     <string name="prefs_bt_frequency_device_hint">蓝牙设备 ID</string>
     <string name="prefs_bt_frequency_output_hint">数据格式</string>
     <string name="prefs_bt_perm_error">请检查蓝牙权限</string>
+    <string name="prefs_net_perm_error">请检查网络权限</string>
 
     <string name="prefs_other_title">其他设置</string>
     <string name="prefs_other_switch_utc">以 UTC 时间显示</string>

core/presentation/src/main/res/values/strings.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <!-- Commmon -->
-    <string name="app_name" translatable="false">Look4Sat</string>
+    <string name="app_name" translatable="false">Look4Sat-CNMap</string>
     <string name="btn_accept">Accept</string>
     <string name="btn_cancel">Cancel</string>
     <string name="empty_list_message">No data to show</string>
@@ -43,15 +43,14 @@
     <string name="pass_empty_list_message">
         Make sure your filters are correct and you have selected satellites</string>
     <string name="pass_error_message">There are no upcoming satellite passes to display</string>
-    <string name="pass_welcome_title">Welcome to Look4Sat\!</string>
+    <string name="pass_welcome_title">Welcome to Look4Sat-CNMap\!</string>
     <string name="pass_welcome_message">
         Make sure to set your position via GPS, Lat/Lon or QTH in Settings.
         \n\nPlease update the database at least weekly to get accurate predictions.</string>
-    <string name="pass_whatsnew_title" translatable="false">What\'s new in Look4Sat</string>
+    <string name="pass_whatsnew_title" translatable="false">What\'s new in Look4Sat-CNMap</string>
     <string name="pass_whatsnew_message" translatable="false">
-        * Merged RadarScreen and RadioControlScreen functionality
-        \n\n* Added SSTV image decoding functionality to RadarScreen
-        \n\n* Added colored elevation and decay check to satellite passes
+        * Added required tweaks to support Android 17 (API 37)
+        \n\n* Added ACCESS_LOCAL_NETWORK permission check to support network data output
     </string>
 
     <!-- Radar screen -->
@@ -83,7 +82,8 @@
     <!-- Map screen -->
     <string name="map_prev">Prev</string>
     <string name="map_next">Next</string>
-    <string name="map_copyright" translatable="false">© OpenStreetMap contributors</string>
+    <string name="map_copyright_osm" translatable="false">© OpenStreetMap contributors</string>
+    <string name="map_copyright_tianditu" translatable="false">© Tianditu</string>
     <string name="map_azimuth">Azimuth: %.1f°</string>
     <string name="map_elevation">Elevation: %.1f°</string>
     <string name="map_altitude">Altitude: %.0f km</string>
@@ -99,12 +99,12 @@
     <string name="map_visible">Visible</string>
 
     <!-- Settings screen -->
-    <string name="prefs_app_title" translatable="false">Look4Sat v%s</string>
-    <string name="prefs_app_url" translatable="false">https://play.google.com/store/apps/details?id=com.rtbishop.look4sat</string>
+    <string name="prefs_app_title" translatable="false">Look4Sat-CNMap v%s</string>
+    <string name="prefs_app_url" translatable="false">https://play.google.com/store/apps/details?id=cn.bh2vsq.look4sat</string>
     <string name="prefs_donate_title">Donate</string>
     <string name="prefs_donate_url" translatable="false">https://ko-fi.com/rt_bishop</string>
     <string name="prefs_fdroid_title" translatable="false">F-Droid</string>
-    <string name="prefs_fdroid_url" translatable="false">https://f-droid.org/en/packages/com.rtbishop.look4sat/</string>
+    <string name="prefs_fdroid_url" translatable="false">https://f-droid.org/en/packages/cn.bh2vsq.look4sat/</string>
     <string name="prefs_github_title" translatable="false">GitHub</string>
     <string name="prefs_github_url" translatable="false">https://github.com/rt-bishop/Look4Sat/</string>
     <string name="prefs_license_title" translatable="false">GPLv3</string>
@@ -148,6 +148,13 @@
     <string name="prefs_bt_output">Bluetooth</string>
     <string name="prefs_cat_output">CAT</string>
 
+    <string name="prefs_map_title">Map settings</string>
+    <string name="prefs_map_source_osm" translatable="false">OSM</string>
+    <string name="prefs_map_source_tianditu_vector" translatable="false">天地图-矢量</string>
+    <string name="prefs_map_source_tianditu_image" translatable="false">天地图-影像</string>
+    <string name="prefs_map_tianditu_key" translatable="false">天地图密钥</string>
+    <string name="prefs_map_save_key">保存密钥</string>
+
     <!-- Radio Control -->
     <string name="nav_radiocontrol">Radio Control</string>
     <string name="rc_settings_title">CAT Radio Control</string>
@@ -174,6 +181,7 @@
     <string name="prefs_bt_frequency_device_hint">Device id</string>
     <string name="prefs_bt_frequency_output_hint">Data format</string>
     <string name="prefs_bt_perm_error">Check your bluetooth permission</string>
+    <string name="prefs_net_perm_error">Check your network permission</string>
 
     <string name="prefs_other_title">Other settings</string>
     <string name="prefs_other_switch_utc">Show pass time in UTC</string>

core/presentation/src/test/java/com/rtbishop/look4sat/core/presentation/DeeplinkResolverTest.kt

@@ -0,0 +1,39 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.presentation
+
+import org.junit.Test
+
+class DeeplinkResolverTest {
+
+    @Test
+    fun returnsDefaultDestination() {
+        val deeplinkResolver = DeeplinkResolver()
+        val result = deeplinkResolver.resolve("/deeplink")
+        assert(result == Screen.Passes)
+    }
+
+    @Test
+    fun returnsRadarDestination() {
+        val passId = "some-pass-id"
+        val passDeeplink = "https://github.com/rt-bishop/Look4Sat/passes/$passId"
+        val deeplinkResolver = DeeplinkResolver()
+        val result = deeplinkResolver.resolve(passDeeplink)
+        assert(result == RadarDestination)
+    }
+}

fastlane/metadata/android/en-US/changelogs/default.txt

@@ -1,3 +1,2 @@
-* Merged RadarScreen and RadioControlScreen functionality
-* Added SSTV image decoding functionality to RadarScreen
-* Added colored elevation and decay check to satellite passes
+* Added required tweaks to support Android 17 (API 37)
+* Added ACCESS_LOCAL_NETWORK permission check to support network data output

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapNightOverlay.kt

@@ -1,152 +0,0 @@
-/*
- * Look4Sat. Amateur radio satellite tracker and pass predictor.
- * Copyright (C) 2019-2026 Arty Bishop and contributors.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-package com.rtbishop.look4sat.feature.map
-
-import android.graphics.Canvas
-import android.graphics.Color
-import android.graphics.Paint
-import android.graphics.RectF
-import org.osmdroid.views.MapView
-import org.osmdroid.views.overlay.Overlay
-import kotlin.math.cos
-import kotlin.math.sin
-
-/**
- * Custom osmdroid overlay that shades the night side of the globe.
- *
- * Works entirely in screen-pixel space: for each vertical strip on screen it
- * asks osmdroid for the geographic coordinate, then tests whether that point is
- * in the night half-sphere relative to the sub-solar point.  Because the
- * computation happens during draw() the result is always correct regardless
- * of zoom level or map scroll position — no polygon winding issues possible.
- *
- * A point (latRad, lonRad) is in night when the angle to the sub-solar point
- * exceeds 90°, i.e. the dot product of the two unit vectors is negative:
- *   dot = sin(lat)*sin(sunLat) + cos(lat)*cos(sunLat)*cos(lon - sunLon) < 0
- *
- * Performance: we sample one column per [stepPx] pixels (default 4) and draw
- * filled vertical rectangles.  On a 1080-wide screen this means ~270 trig
- * evaluations per row, which is imperceptible.
- */
-class MapNightOverlay : Overlay() {
-
-    /** Sub-solar latitude in degrees. */
-    var sunLatDeg: Double = 0.0
-
-    /** Sub-solar longitude in degrees. */
-    var sunLonDeg: Double = 0.0
-
-    private val nightPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
-        style = Paint.Style.FILL
-        color = Color.argb(75, 0, 0, 0)
-    }
-
-    private val rect = RectF()
-
-    override fun draw(canvas: Canvas, mapView: MapView, shadow: Boolean) {
-        if (shadow) return
-
-        val proj = mapView.projection
-        val sunLatRad = Math.toRadians(sunLatDeg)
-        val sunLonRad = Math.toRadians(sunLonDeg)
-        val sinSunLat = sin(sunLatRad)
-        val cosSunLat = cos(sunLatRad)
-
-        val w = mapView.width
-        val h = mapView.height
-        val stepPx = 4 // sample every N pixels — balance quality vs CPU
-
-        // We scan column by column. For each column we determine the longitude,
-        // then find the latitude range that is in night and shade it.
-        // Since longitude is constant along a vertical strip and the day/night
-        // boundary at a given longitude is at most two latitudes, we can do a
-        // scan-line fill efficiently.
-
-        var x = 0
-        while (x < w) {
-            // Get the geographic coordinate at the top and bottom of this column.
-            val geoTop = proj.fromPixels(x, 0) ?: run { x += stepPx; continue }
-            val geoBot = proj.fromPixels(x, h - 1) ?: run { x += stepPx; continue }
-
-            val lonRad = Math.toRadians(geoTop.longitude)
-            val cosLonDiff = cos(lonRad - sunLonRad)
-
-            // Top pixel geographic lat
-            val latTopRad = Math.toRadians(geoTop.latitude)
-            // Bottom pixel geographic lat (osmdroid: y=0 is top of screen, higher y = lower lat)
-            val latBotRad = Math.toRadians(geoBot.latitude)
-
-            // dot(sunVec, pointVec) < 0 → night
-            // dot = sin(lat)*sinSunLat + cos(lat)*cosSunLat*cosLonDiff
-            val dotTop = sin(latTopRad) * sinSunLat + cos(latTopRad) * cosSunLat * cosLonDiff
-            val dotBot = sin(latBotRad) * sinSunLat + cos(latBotRad) * cosSunLat * cosLonDiff
-
-            when {
-                dotTop < 0 && dotBot < 0 -> {
-                    // Entire column is night — shade from top to bottom
-                    rect.set(x.toFloat(), 0f, (x + stepPx).toFloat(), h.toFloat())
-                    canvas.drawRect(rect, nightPaint)
-                }
-
-                dotTop >= 0 && dotBot >= 0 -> {
-                    // Entire column is day — nothing to draw
-                }
-
-                else -> {
-                    // Terminator crosses this column — find the crossing pixel by binary search
-                    val crossY = findCrossingY(proj, x, 0, h - 1, sinSunLat, cosSunLat, cosLonDiff)
-                    if (dotTop < 0) {
-                        // Night at top, day at bottom
-                        rect.set(x.toFloat(), 0f, (x + stepPx).toFloat(), crossY.toFloat())
-                        canvas.drawRect(rect, nightPaint)
-                    } else {
-                        // Day at top, night at bottom
-                        rect.set(x.toFloat(), crossY.toFloat(), (x + stepPx).toFloat(), h.toFloat())
-                        canvas.drawRect(rect, nightPaint)
-                    }
-                }
-            }
-            x += stepPx
-        }
-    }
-
-    /**
-     * Binary-search for the pixel row where the day/night boundary crosses column [x].
-     * [yTop] is in day, [yBot] is in night (or vice versa).
-     */
-    private fun findCrossingY(
-        proj: org.osmdroid.views.Projection,
-        x: Int,
-        yTop: Int,
-        yBot: Int,
-        sinSunLat: Double,
-        cosSunLat: Double,
-        cosLonDiff: Double
-    ): Int {
-        var lo = yTop
-        var hi = yBot
-        while (hi - lo > 1) {
-            val mid = (lo + hi) / 2
-            val geo = proj.fromPixels(x, mid) ?: return mid
-            val latRad = Math.toRadians(geo.latitude)
-            val dot = sin(latRad) * sinSunLat + cos(latRad) * cosSunLat * cosLonDiff
-            if (dot < 0) hi = mid else lo = mid
-        }
-        return (lo + hi) / 2
-    }
-}

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapScreen.kt

@@ -60,6 +60,7 @@ import androidx.lifecycle.LifecycleEventObserver
 import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
+import com.rtbishop.look4sat.core.domain.model.MapSource
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.OrbitalObject
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
@@ -71,37 +72,56 @@ import com.rtbishop.look4sat.core.presentation.TimerRow
 import com.rtbishop.look4sat.core.presentation.TopBar
 import com.rtbishop.look4sat.core.presentation.isVerticalLayout
 import com.rtbishop.look4sat.core.presentation.layoutPadding
+import org.osmdroid.config.Configuration
+import org.osmdroid.tileprovider.MapTileProviderBasic
+import org.osmdroid.tileprovider.tilesource.OnlineTileSourceBase
+import org.osmdroid.tileprovider.tilesource.TileSourceFactory
 import org.osmdroid.tileprovider.tilesource.XYTileSource
 import org.osmdroid.util.GeoPoint
+import org.osmdroid.util.MapTileIndex
 import org.osmdroid.views.CustomZoomButtonsController
 import org.osmdroid.views.MapView
 import org.osmdroid.views.overlay.FolderOverlay
 import org.osmdroid.views.overlay.Marker
 import org.osmdroid.views.overlay.Polyline
+import org.osmdroid.views.overlay.TilesOverlay
+import java.io.File
+import java.net.URLEncoder
 
 // Overlay indices
-private const val OVERLAY_STATION = 0
-private const val OVERLAY_TRACK = 1
-private const val OVERLAY_FOOTPRINT = 2
-private const val OVERLAY_POSITIONS = 3
-private const val OVERLAY_TERMINATOR = 4
+private const val OVERLAY_TDT_LABELS = 0
+private const val OVERLAY_STATION = 1
+private const val OVERLAY_TRACK = 2
+private const val OVERLAY_FOOTPRINT = 3
+private const val OVERLAY_POSITIONS = 4
 private const val OVERLAY_SUN = 5
 private const val OVERLAY_MOON = 6
 private const val OVERLAY_COUNT = 7
 
 private val minLat = MapView.getTileSystem().minLatitude
 private val maxLat = MapView.getTileSystem().maxLatitude
+private val offlineTileSource = XYTileSource("tiles", 0, 6, 256, ".webp", emptyArray<String>())
+private const val OFFLINE_MAX_ZOOM = 7.0
+private const val OSM_MAX_ZOOM = 19.0
+private const val TIANDITU_MAX_ZOOM = 18.0
+private const val TILE_CACHE_MAX_BYTES = 1024L * 1024L * 1024L
+private const val TILE_CACHE_TRIM_BYTES = 900L * 1024L * 1024L
+private const val TILE_REFRESH_DELAY_MS = 250L
+private const val TILE_SOURCE_OSM = "osm"
+private const val TILE_USER_AGENT = "Look4Sat-CNMap"
 private val trackPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
-    strokeWidth = 3f
+    strokeWidth = 4f
     style = Paint.Style.STROKE
-    color = Color.RED
+    color = "#1565C0".toColorInt()
     strokeCap = Paint.Cap.ROUND
     strokeJoin = Paint.Join.ROUND
 }
-private val footprintPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
-    strokeWidth = 3f
-    style = Paint.Style.FILL_AND_STROKE
-    color = "#FFE082".toColorInt()
+private val footprintOutlinePaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+    strokeWidth = 4f
+    style = Paint.Style.STROKE
+    color = "#00897B".toColorInt()
+    strokeCap = Paint.Cap.ROUND
+    strokeJoin = Paint.Join.ROUND
 }
 private val textPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
     textSize = 36f
@@ -134,11 +154,17 @@ private fun MapScreen(uiState: MapState, onAction: (MapAction) -> Unit, mapView:
     val rotateMod = Modifier.rotate(180f)
     val timeString = uiState.mapData?.aosTime ?: "00:00:00"
     val isTimeAos = uiState.mapData?.isTimeAos ?: true
+    val usesTianditu = tiandituLayers(uiState.mapSource) != null && uiState.tiandituKey.isNotBlank()
+    val copyrightResId = if (usesTianditu) R.string.map_copyright_tianditu
+    else R.string.map_copyright_osm
 
     LaunchedEffect(uiState.track) {
         val firstPos = uiState.track?.firstOrNull()?.firstOrNull() ?: return@LaunchedEffect
         mapView.controller.animateTo(GeoPoint(firstPos.latitude, firstPos.longitude))
     }
+    LaunchedEffect(uiState.mapSource, uiState.tiandituKey) {
+        configureTileSources(mapView, uiState.mapSource, uiState.tiandituKey)
+    }
     Column(modifier = Modifier.layoutPadding(), verticalArrangement = Arrangement.spacedBy(6.dp)) {
         val isVertical = isVerticalLayout()
         if (isVertical) {
@@ -163,13 +189,12 @@ private fun MapScreen(uiState: MapState, onAction: (MapAction) -> Unit, mapView:
                     uiState.track?.let { setSatelliteTrack(it, view) }
                     uiState.footprint?.let { setFootprint(it, view) }
                     uiState.positions?.let { setPositions(it, view) { item -> onAction(MapAction.SelectItem(item)) } }
-                    setTerminator(uiState.sunLatDeg, uiState.sunLonDeg, view)
                     setSubSolarPoint(uiState.sunLatDeg, uiState.sunLonDeg, view)
                     setMoonPosition(uiState.moonLatDeg, uiState.moonLonDeg, view)
                     view.invalidate()
                 }
                 uiState.mapData?.let { mapData ->
-                    if (isVertical) MapDataCard(mapData) else MapDataCards(mapData)
+                    if (isVertical) MapDataCard(mapData, copyrightResId) else MapDataCards(mapData, copyrightResId)
                 }
             }
         }
@@ -178,11 +203,11 @@ private fun MapScreen(uiState: MapState, onAction: (MapAction) -> Unit, mapView:
 
 // region Map data composables
 @Composable
-private fun MapDataCard(data: MapData) {
+private fun MapDataCard(data: MapData, copyrightResId: Int) {
     val textColor = MaterialTheme.colorScheme.primary
     val cardColors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerLowest)
     Column(horizontalAlignment = Alignment.CenterHorizontally) {
-        Text(text = stringResource(R.string.map_copyright), fontSize = 14.sp)
+        Text(text = stringResource(copyrightResId), fontSize = 14.sp)
         Card(colors = cardColors) {
             Column(modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp)) {
                 MapDataRow(
@@ -220,7 +245,7 @@ private fun MapDataRow(
 }
 
 @Composable
-private fun MapDataCards(data: MapData) {
+private fun MapDataCards(data: MapData, copyrightResId: Int) {
     val cardColors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerLowest)
     val paddingMod = Modifier
         .padding(horizontal = 8.dp, vertical = 4.dp)
@@ -246,7 +271,7 @@ private fun MapDataCards(data: MapData) {
             }
         }
         Text(
-            text = stringResource(R.string.map_copyright),
+            text = stringResource(copyrightResId),
             fontSize = 14.sp,
             modifier = Modifier.align(Alignment.BottomCenter)
         )
@@ -260,6 +285,114 @@ private fun MapDataCards(data: MapData) {
 }
 // endregion
 
+// region Tile sources
+private var configuredTileMapView: MapView? = null
+private var configuredTileSource: String? = null
+
+private fun configureTileSources(mapView: MapView, mapSource: String, tiandituKey: String) {
+    val key = tiandituKey.trim()
+    val layers = tiandituLayers(mapSource)
+    val tileSourceKey = if (layers == null || key.isBlank()) {
+        TILE_SOURCE_OSM
+    } else {
+        "tianditu:${layers.base}:${layers.label}:$key"
+    }
+    if (configuredTileMapView === mapView && configuredTileSource == tileSourceKey) {
+        requestTileRefresh(mapView)
+        return
+    }
+    configuredTileMapView = mapView
+    configuredTileSource = tileSourceKey
+
+    if (layers == null || key.isBlank()) {
+        mapView.setUseDataConnection(true)
+        mapView.setTileProvider(MapTileProviderBasic(mapView.context, TileSourceFactory.MAPNIK))
+        mapView.maxZoomLevel = OSM_MAX_ZOOM
+        mapView.overlayManager.tilesOverlay.applyTileOverlayDefaults()
+        mapView.overlays[OVERLAY_TDT_LABELS] = FolderOverlay()
+        requestTileRefresh(mapView)
+        return
+    }
+    mapView.setUseDataConnection(true)
+    mapView.setTileProvider(MapTileProviderBasic(mapView.context, TiandituTileSource(layer = layers.base, key = key)))
+    mapView.maxZoomLevel = TIANDITU_MAX_ZOOM
+    mapView.overlayManager.tilesOverlay.applyTileOverlayDefaults()
+    mapView.overlays[OVERLAY_TDT_LABELS] = TilesOverlay(
+        MapTileProviderBasic(mapView.context, TiandituTileSource(layer = layers.label, key = key)),
+        mapView.context
+    ).apply {
+        applyTileOverlayDefaults()
+        setUseDataConnection(true)
+    }
+    requestTileRefresh(mapView)
+}
+
+private data class TiandituLayers(val base: String, val label: String)
+
+private fun tiandituLayers(mapSource: String): TiandituLayers? = when (MapSource.normalize(mapSource)) {
+    MapSource.TIANDITU_VECTOR -> TiandituLayers(base = "vec", label = "cva")
+    MapSource.TIANDITU_IMAGE -> TiandituLayers(base = "img", label = "cia")
+    else -> null
+}
+
+private fun TilesOverlay.applyTileOverlayDefaults() {
+    setColorFilter(null)
+    setLoadingBackgroundColor(Color.TRANSPARENT)
+    setLoadingLineColor(Color.TRANSPARENT)
+}
+
+private fun requestTileRefresh(mapView: MapView) {
+    mapView.post {
+        mapView.requestLayout()
+        mapView.invalidate()
+        mapView.postInvalidate()
+    }
+    mapView.postDelayed({
+        mapView.invalidate()
+        mapView.postInvalidate()
+    }, TILE_REFRESH_DELAY_MS)
+}
+
+private fun buildTiandituWmtsUrl(
+    baseUrl: String,
+    layer: String,
+    zoom: Int,
+    row: Int,
+    col: Int,
+    encodedKey: String
+): String = "$baseUrl?SERVICE=WMTS&REQUEST=GetTile&VERSION=1.0.0&LAYER=$layer" +
+    "&STYLE=default&TILEMATRIXSET=w&FORMAT=tiles&TILEMATRIX=$zoom&TILEROW=$row&TILECOL=$col&tk=$encodedKey"
+
+private class TiandituTileSource(
+    private val layer: String,
+    private val key: String
+) : OnlineTileSourceBase(
+    "tianditu-wmts-https-$layer",
+    1,
+    18,
+    256,
+    ".png",
+    Array(8) { index -> "https://t$index.tianditu.gov.cn/${layer}_w/wmts" },
+    "Tianditu"
+) {
+    private val encodedKey = URLEncoder.encode(key, Charsets.UTF_8.name())
+
+    override fun getTileURLString(pMapTileIndex: Long): String {
+        val zoom = MapTileIndex.getZoom(pMapTileIndex)
+        val row = MapTileIndex.getY(pMapTileIndex)
+        val col = MapTileIndex.getX(pMapTileIndex)
+        return buildTiandituWmtsUrl(
+            baseUrl = getBaseUrl(),
+            layer = layer,
+            zoom = zoom,
+            row = row,
+            col = col,
+            encodedKey = encodedKey
+        )
+    }
+}
+// endregion
+
 // region Map overlay helpers
 private fun setStationPosition(stationPos: GeoPos, mapView: MapView) {
     try {
@@ -282,6 +415,8 @@ private fun setStationPosition(stationPos: GeoPos, mapView: MapView) {
 /** Pool of reusable Marker objects keyed by satellite name, to avoid re-creation every frame */
 private val markerPool = HashMap<String, Marker>()
 private var lastMapView: MapView? = null
+private var lastSatelliteTrack: List<List<GeoPos>>? = null
+private var satelliteTrackOverlay: FolderOverlay? = null
 
 private fun setPositions(
     posMap: Map<OrbitalObject, GeoPos>,
@@ -294,8 +429,9 @@ private fun setPositions(
             lastMapView = mapView
             markerPool.clear()
             iconCache.evictAll()
-            footprintPolyline = null
-            footprintPoints = null
+            lastSatelliteTrack = null
+            satelliteTrackOverlay = null
+            footprintOverlay = null
         }
         // Reuse the existing FolderOverlay — creating a new one and replacing it
         // causes osmdroid to detach shared Marker objects, making them invisible.
@@ -357,6 +493,10 @@ private fun getCachedTextIcon(name: String, mapView: MapView): Drawable {
 }
 
 private fun setSatelliteTrack(satTrack: List<List<GeoPos>>, mapView: MapView) {
+    val cachedOverlay = satelliteTrackOverlay
+    if (lastSatelliteTrack === satTrack && cachedOverlay != null && mapView.overlays[OVERLAY_TRACK] === cachedOverlay) {
+        return
+    }
     val trackOverlay = FolderOverlay()
     try {
         satTrack.forEach { track ->
@@ -366,61 +506,76 @@ private fun setSatelliteTrack(satTrack: List<List<GeoPos>>, mapView: MapView) {
                 trackOverlay.add(this)
             }
         }
+        lastSatelliteTrack = satTrack
+        satelliteTrackOverlay = trackOverlay
         mapView.overlays[OVERLAY_TRACK] = trackOverlay
     } catch (e: Exception) {
         println(e)
     }
 }
 
-/** Reusable footprint Polyline — created once, points updated in-place each frame */
-private var footprintPolyline: Polyline? = null
-private var footprintPoints: ArrayList<GeoPoint>? = null
+/** Reusable footprint overlay - split at the date line so wrapped maps don't drop the circle. */
+private var footprintOverlay: FolderOverlay? = null
 
 private fun setFootprint(orbitalPos: OrbitalPos, mapView: MapView) {
     try {
         val rangeCircle = orbitalPos.getRangeCircle()
-        var pts = footprintPoints
-        if (pts == null || pts.size != rangeCircle.size) {
-            pts = ArrayList(rangeCircle.size)
-            for (gp in rangeCircle) pts.add(GeoPoint(gp.latitude, gp.longitude))
-            footprintPoints = pts
-        } else {
-            for (i in rangeCircle.indices) {
-                pts[i].latitude = rangeCircle[i].latitude
-                pts[i].longitude = rangeCircle[i].longitude
+        val overlay = footprintOverlay ?: FolderOverlay().also { footprintOverlay = it }
+        overlay.items.clear()
+        splitClosedPathOnDateLine(rangeCircle).forEach { segment ->
+            if (segment.size > 1) {
+                overlay.add(
+                    Polyline().apply {
+                        setPoints(segment.map { GeoPoint(it.latitude, it.longitude) })
+                        outlinePaint.set(footprintOutlinePaint)
+                    }
+                )
             }
         }
-        val polyline = footprintPolyline ?: Polyline().apply {
-            outlinePaint.set(footprintPaint)
-            footprintPolyline = this
-        }
-        polyline.setPoints(pts)
-        mapView.overlays[OVERLAY_FOOTPRINT] = polyline
+        mapView.overlays[OVERLAY_FOOTPRINT] = overlay
     } catch (e: Exception) {
         println(e)
     }
 }
 
-/**
- * Update the NightOverlay with the current sub-solar position.
- * The overlay is created once and kept in OVERLAY_TERMINATOR; only its
- * sunLatDeg/sunLonDeg fields are updated each tick so osmdroid redraws it.
- */
-private fun setTerminator(sunLatDeg: Double, sunLonDeg: Double, mapView: MapView) {
-    try {
-        val overlay = mapView.overlays[OVERLAY_TERMINATOR]
-        if (overlay is MapNightOverlay) {
-            overlay.sunLatDeg = sunLatDeg
-            overlay.sunLonDeg = sunLonDeg
-        } else {
-            mapView.overlays[OVERLAY_TERMINATOR] = MapNightOverlay().apply {
-                this.sunLatDeg = sunLatDeg
-                this.sunLonDeg = sunLonDeg
+private fun splitClosedPathOnDateLine(points: List<GeoPos>): List<List<GeoPos>> {
+    if (points.isEmpty()) return emptyList()
+    val segments = mutableListOf<List<GeoPos>>()
+    val segment = mutableListOf<GeoPos>()
+    var previous = points.first()
+    segment.add(previous)
+    (points.drop(1) + points.first()).forEach { current ->
+        when {
+            previous.longitude < -170.0 && current.longitude > 170.0 -> {
+                val edgeLatitude = getDateLineLatitude(previous, current, -180.0)
+                segment.add(GeoPos(edgeLatitude, -180.0))
+                segments.add(segment.toList())
+                segment.clear()
+                segment.add(GeoPos(edgeLatitude, 180.0))
+            }
+            previous.longitude > 170.0 && current.longitude < -170.0 -> {
+                val edgeLatitude = getDateLineLatitude(previous, current, 180.0)
+                segment.add(GeoPos(edgeLatitude, 180.0))
+                segments.add(segment.toList())
+                segment.clear()
+                segment.add(GeoPos(edgeLatitude, -180.0))
             }
         }
-    } catch (e: Exception) {
-        println(e)
+        segment.add(current)
+        previous = current
     }
+    if (segment.size > 1) segments.add(segment)
+    return segments
+}
+
+private fun getDateLineLatitude(previous: GeoPos, current: GeoPos, edgeLongitude: Double): Double {
+    val currentLongitude = when {
+        previous.longitude < -170.0 && current.longitude > 170.0 -> current.longitude - 360.0
+        previous.longitude > 170.0 && current.longitude < -170.0 -> current.longitude + 360.0
+        else -> current.longitude
+    }
+    val fraction = (edgeLongitude - previous.longitude) / (currentLongitude - previous.longitude)
+    return previous.latitude + (current.latitude - previous.latitude) * fraction
 }
 
 /** Place an ic_sun icon marker at the sub-solar point. */
@@ -482,40 +637,62 @@ private fun setMoonPosition(moonLatDeg: Double, moonLonDeg: Double, mapView: Map
 // region MapView lifecycle
 @Composable
 private fun rememberMapViewWithLifecycle(): MapView {
-    val tileSource = XYTileSource("tiles", 0, 6, 256, ".webp", emptyArray<String>())
     val context = LocalContext.current
     val isVertical = isVerticalLayout()
     val mapView = remember {
+        configureOsmdroidCache(context)
         MapView(context).apply {
             setMultiTouchControls(true)
             setUseDataConnection(false)
-            setTileSource(tileSource)
+            setTileSource(offlineTileSource)
             minZoomLevel = getMinZoom(resources.displayMetrics.heightPixels, isVertical)
-            maxZoomLevel = 7.0
+            maxZoomLevel = OFFLINE_MAX_ZOOM
             controller.setCenter(GeoPoint(48.8575, 6.3514))
             controller.setZoom(minZoomLevel + 2)
             zoomController.setVisibility(CustomZoomButtonsController.Visibility.NEVER)
             overlayManager.tilesOverlay.loadingBackgroundColor = Color.TRANSPARENT
             overlayManager.tilesOverlay.loadingLineColor = Color.TRANSPARENT
             overlayManager.tilesOverlay.setColorFilter(createColorFilter())
+            setHorizontalMapRepetitionEnabled(true)
+            setVerticalMapRepetitionEnabled(false)
             setScrollableAreaLimitLatitude(maxLat, minLat, 0)
             overlays.addAll(Array(OVERLAY_COUNT) { FolderOverlay() })
+            addOnFirstLayoutListener { _, _, _, _, _ -> requestTileRefresh(this) }
         }
     }
     val lifecycleObserver = rememberMapViewLifecycleObserver(mapView)
     val lifecycle = LocalLifecycleOwner.current.lifecycle
     DisposableEffect(lifecycle) {
         lifecycle.addObserver(lifecycleObserver)
+        if (lifecycle.currentState.isAtLeast(Lifecycle.State.STARTED)) {
+            mapView.onResume()
+            requestTileRefresh(mapView)
+        }
         onDispose { lifecycle.removeObserver(lifecycleObserver) }
     }
     return mapView
 }
 
+private fun configureOsmdroidCache(context: android.content.Context) {
+    val cacheRoot = File(context.filesDir, "osmdroid")
+    val tileCache = File(cacheRoot, "tiles")
+    Configuration.getInstance().apply {
+        setUserAgentValue(TILE_USER_AGENT)
+        setOsmdroidBasePath(cacheRoot)
+        setOsmdroidTileCache(tileCache)
+        setTileFileSystemCacheMaxBytes(TILE_CACHE_MAX_BYTES)
+        setTileFileSystemCacheTrimBytes(TILE_CACHE_TRIM_BYTES)
+    }
+}
+
 @Composable
 private fun rememberMapViewLifecycleObserver(mapView: MapView) = remember(mapView) {
     LifecycleEventObserver { _, event ->
         when (event) {
-            Lifecycle.Event.ON_RESUME -> mapView.onResume()
+            Lifecycle.Event.ON_RESUME -> {
+                mapView.onResume()
+                requestTileRefresh(mapView)
+            }
             Lifecycle.Event.ON_PAUSE -> mapView.onPause()
             else -> {}
         }

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapState.kt

@@ -26,6 +26,8 @@ data class MapState(
     val mapData: MapData? = null,
     val isLightUi: Boolean = false,
     val isUtc: Boolean = false,
+    val mapSource: String = "",
+    val tiandituKey: String = "",
     val stationPosition: GeoPos? = null,
     val orbitalPass: OrbitalPass,
     val track: List<List<GeoPos>>? = null,

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapViewModel.kt

@@ -32,6 +32,7 @@ import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
 import com.rtbishop.look4sat.core.domain.utility.clipLat
 import com.rtbishop.look4sat.core.domain.utility.clipLon
 import com.rtbishop.look4sat.core.domain.utility.positionToQth
+import com.rtbishop.look4sat.core.domain.utility.toMapGeoPos
 import com.rtbishop.look4sat.core.domain.utility.toDegrees
 import com.rtbishop.look4sat.core.domain.utility.toTimerString
 import com.rtbishop.look4sat.core.presentation.getDefaultPass
@@ -60,6 +61,8 @@ class MapViewModel(
         MapState(
             isLightUi = settingsRepo.otherSettings.value.stateOfLightTheme,
             isUtc = settingsRepo.otherSettings.value.stateOfUtc,
+            mapSource = settingsRepo.otherSettings.value.mapSource,
+            tiandituKey = settingsRepo.otherSettings.value.tiandituKey,
             orbitalPass = defaultPass
         )
     )
@@ -73,7 +76,13 @@ class MapViewModel(
     init {
         viewModelScope.launch {
             settingsRepo.otherSettings.collectLatest { settings ->
-                _uiState.update { it.copy(isUtc = settings.stateOfUtc) }
+                _uiState.update {
+                    it.copy(
+                        isUtc = settings.stateOfUtc,
+                        mapSource = settings.mapSource,
+                        tiandituKey = settings.tiandituKey
+                    )
+                }
             }
         }
         val (selectedCatNum, _) = satelliteRepo.selectedPass.value
@@ -166,9 +175,7 @@ class MapViewModel(
                     var localSelectedPos: OrbitalPos? = null
                     for (satellite in chunk) {
                         val satPos = satelliteRepo.getPosition(satellite, pos, date.time)
-                        val osmLat = clipLat(satPos.latitude.toDegrees())
-                        val osmLon = clipLon(satPos.longitude.toDegrees())
-                        localPositions.add(satellite to GeoPos(osmLat, osmLon))
+                        localPositions.add(satellite to satPos.toMapGeoPos())
                         if (satellite === selected) {
                             localSelectedPos = satPos
                         }
@@ -242,9 +249,7 @@ class MapViewModel(
             }
         val azimuth = satPos.azimuth.toDegrees()
         val elevation = satPos.elevation.toDegrees()
-        val osmLat = clipLat(satPos.latitude.toDegrees())
-        val osmLon = clipLon(satPos.longitude.toDegrees())
-        val osmPos = GeoPos(osmLat, osmLon)
+        val osmPos = satPos.toMapGeoPos()
         val qthLoc = positionToQth(osmPos.latitude, osmPos.longitude) ?: "-- --"
         val velocity = satPos.getOrbitalVelocity()
         val phase = satPos.phase.toDegrees()
@@ -272,31 +277,45 @@ class MapViewModel(
         val satTracks = mutableListOf<List<GeoPos>>()
         val currentTrack = mutableListOf<GeoPos>()
         val endDate = Date(date.time + (orbitalObject.data.orbitalPeriod * 2.4 * 60000L).toLong())
-        var oldLongitude = 0.0
+        var previousPosition: GeoPos? = null
         satelliteRepo.getTrack(orbitalObject, pos, date.time, endDate.time).forEach { satPos ->
-            val osmLat = clipLat(satPos.latitude.toDegrees())
-            val osmLon = clipLon(satPos.longitude.toDegrees())
-            val currentPosition = GeoPos(osmLat, osmLon)
-            if (oldLongitude < -170.0 && currentPosition.longitude > 170.0) {
+            val currentPosition = satPos.toMapGeoPos()
+            val previous = previousPosition
+            if (previous != null && previous.longitude < -170.0 && currentPosition.longitude > 170.0) {
                 // adding left terminal position
-                currentTrack.add(GeoPos(osmLat, -180.0))
+                val edgeLatitude = getDateLineLatitude(previous, currentPosition)
+                currentTrack.add(GeoPos(edgeLatitude, -180.0))
                 val finishedTrack = mutableListOf<GeoPos>().apply { addAll(currentTrack) }
                 satTracks.add(finishedTrack)
                 currentTrack.clear()
-            } else if (oldLongitude > 170.0 && currentPosition.longitude < -170.0) {
+                currentTrack.add(GeoPos(edgeLatitude, 180.0))
+            } else if (previous != null && previous.longitude > 170.0 && currentPosition.longitude < -170.0) {
                 // adding right terminal position
-                currentTrack.add(GeoPos(osmLat, 180.0))
+                val edgeLatitude = getDateLineLatitude(previous, currentPosition)
+                currentTrack.add(GeoPos(edgeLatitude, 180.0))
                 val finishedTrack = mutableListOf<GeoPos>().apply { addAll(currentTrack) }
                 satTracks.add(finishedTrack)
                 currentTrack.clear()
+                currentTrack.add(GeoPos(edgeLatitude, -180.0))
             }
-            oldLongitude = currentPosition.longitude
+            previousPosition = currentPosition
             currentTrack.add(currentPosition)
         }
         satTracks.add(currentTrack)
         _uiState.update { it.copy(track = satTracks) }
     }
 
+    private fun getDateLineLatitude(previous: GeoPos, current: GeoPos): Double {
+        val currentLon = if (previous.longitude < 0.0 && current.longitude > 0.0) {
+            current.longitude - 360.0
+        } else {
+            current.longitude + 360.0
+        }
+        val edgeLon = if (previous.longitude < 0.0) -180.0 else 180.0
+        val fraction = (edgeLon - previous.longitude) / (currentLon - previous.longitude)
+        return previous.latitude + (current.latitude - previous.latitude) * fraction
+    }
+
     companion object {
         /** Number of parallel chunks for satellite position computation */
         private const val PARALLEL_CHUNKS = 4

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/RadarScreen.kt

@@ -66,6 +66,7 @@ import com.rtbishop.look4sat.core.presentation.NextPassRow
 import com.rtbishop.look4sat.core.presentation.R
 import com.rtbishop.look4sat.core.presentation.TimerRow
 import com.rtbishop.look4sat.core.presentation.TopBar
+import com.rtbishop.look4sat.core.presentation.formatFrequency
 import com.rtbishop.look4sat.core.presentation.getDefaultPass
 import com.rtbishop.look4sat.core.presentation.isVerticalLayout
 import com.rtbishop.look4sat.core.presentation.layoutPadding
@@ -170,13 +171,14 @@ private fun PagerCard(
             ) { pageIndex ->
                 when (pages[pageIndex]) {
                     RadarPage.Transceivers -> TransceiversPage(
-                        transceivers = uiState.transmitters,
-                        selectedUuid = uiState.selectedTransmitterUuid,
+                        transceivers = uiState.transceivers.transmitters,
+                        selectedUuid = uiState.transceivers.selectedUuid,
                         radioControl = uiState.radioControl,
                         onAction = onAction
                     )
                     RadarPage.Sstv -> SstvPage(
                         sstv = uiState.sstv,
+                        dopplerFrequency = uiState.transceivers.selectedFrequency?.let { formatFrequency(it) },
                         onAction = onAction,
                         requestMicPermission = requestMicPermission
                     )
@@ -189,25 +191,26 @@ private fun PagerCard(
 @Composable
 private fun RadarCard(uiState: RadarState, modifier: Modifier = Modifier) {
     val satellitePos = uiState.orbitalPos
-    val borderModifier = if (satellitePos?.aboveHorizon == true && satellitePos.eclipsed) {
-        val infiniteTransition = rememberInfiniteTransition(label = "eclipsedBorder")
-        val borderAlpha by infiniteTransition.animateFloat(
-            initialValue = 1.0f,
-            targetValue = 0.0f,
-            animationSpec = infiniteRepeatable(
-                animation = tween(durationMillis = 1000, delayMillis = 25, easing = LinearEasing),
-                repeatMode = RepeatMode.Reverse
-            ),
-            label = "eclipsedBorderAlpha"
-        )
+    val shouldAnimateBorder = satellitePos?.aboveHorizon == true && satellitePos.eclipsed
+    // Always call these composables unconditionally — conditional composable calls violate
+    // Compose's slot-table stability rules and can crash or produce incorrect state
+    val infiniteTransition = rememberInfiniteTransition(label = "eclipsedBorder")
+    val borderAlpha by infiniteTransition.animateFloat(
+        initialValue = 1.0f,
+        targetValue = 0.0f,
+        animationSpec = infiniteRepeatable(
+            animation = tween(durationMillis = 1000, delayMillis = 25, easing = LinearEasing),
+            repeatMode = RepeatMode.Reverse
+        ),
+        label = "eclipsedBorderAlpha"
+    )
+    val borderModifier = if (shouldAnimateBorder) {
         Modifier.border(
             width = 0.5.dp,
             color = MaterialTheme.colorScheme.primary.copy(alpha = borderAlpha),
             shape = MaterialTheme.shapes.medium
         )
-    } else {
-        Modifier
-    }
+    } else Modifier
     ElevatedCard(modifier = modifier.then(borderModifier)) {
         Box(contentAlignment = Alignment.Center) {
             val position = uiState.orbitalPos
@@ -294,4 +297,3 @@ private fun RadarLabel(
         }
     }
 }
-

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/RadarState.kt

@@ -34,7 +34,6 @@ data class RadioPanelState(
 data class RadioControlSubState(
     val txPanel: RadioPanelState = RadioPanelState("TX (Uplink)"),
     val rxPanel: RadioPanelState = RadioPanelState("RX (Downlink)"),
-    val transponders: List<SatRadio> = emptyList(),
     val selectedTransponderUuid: String? = null,
     val txBaseFrequencyHz: Long? = null,
     val ctcssTone: Double? = null,
@@ -42,11 +41,16 @@ data class RadioControlSubState(
     val errorMessage: String? = null
 )
 
+data class TransceiverSubState(
+    val transmitters: List<SatRadio> = emptyList(),
+    val selectedUuid: String? = null,
+    val selectedFrequency: Long? = null,
+)
+
 data class RadarState(
     val currentPass: OrbitalPass? = null,
     val currentTime: String = "00:00:00",
     val isTimeAos: Boolean = true,
-    val isLos: Boolean = false,
     val isUtc: Boolean = false,
     val orientationValues: Pair<Float, Float> = 0f to 0f,
     val orbitalPos: OrbitalPos? = null,
@@ -55,17 +59,16 @@ data class RadarState(
     val shouldUseCompass: Boolean = false,
     val sunPosition: CelestialComputer.SunPosition? = null,
     val moonPosition: CelestialComputer.MoonPosition? = null,
-    val transmitters: List<SatRadio> = emptyList(),
-    val selectedTransmitterUuid: String? = null,
-    val selectedFrequency: Long? = null,
+    val transceivers: TransceiverSubState = TransceiverSubState(),
     val radioControl: RadioControlSubState = RadioControlSubState(),
     val sstv: SstvSubState = SstvSubState()
 )
 
-enum class SstvStatus { Idle, Recording, Saving }
+enum class SstvStatus { Idle, Recording }
 
 data class SstvSubState(
     val status: SstvStatus = SstvStatus.Idle,
+    val isSaving: Boolean = false,
     val hasPermission: Boolean = false,
     val selectedMode: String = "Auto",
     val supportedModes: List<String> = emptyList(),
@@ -77,7 +80,6 @@ sealed interface RadarAction {
     data class SelectTransmitter(val uuid: String) : RadarAction
 
     // Radio control actions
-    data class SelectTransponder(val uuid: String) : RadarAction
     data class SetTxFrequency(val frequencyHz: Long) : RadarAction
     data class AdjustTxFrequency(val deltaHz: Long) : RadarAction
     data class SetCtcssTone(val toneHz: Double?) : RadarAction

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/RadarView.kt

@@ -17,6 +17,7 @@
  */
 package com.rtbishop.look4sat.feature.radar
 
+import androidx.compose.animation.core.LinearEasing
 import androidx.compose.animation.core.animateFloat
 import androidx.compose.animation.core.infiniteRepeatable
 import androidx.compose.animation.core.rememberInfiniteTransition
@@ -64,7 +65,7 @@ import kotlin.math.sin
 
 private const val CIRCLES = 3
 private const val STROKE_WIDTH = 6f
-private const val SWEEP_INCREMENT = 360f / 12f / 60f
+private const val SWEEP_DURATION_MS = 8_000
 
 @Composable
 fun RadarViewCompose(
@@ -88,23 +89,44 @@ fun RadarViewCompose(
         animationSpec = infiniteRepeatable(tween(1000)),
         label = "animScale"
     )
+    // Drive the sweep from the animation framework to eliminate state mutation inside the draw block
+    val sweepTransition = rememberInfiniteTransition(label = "sweep")
+    val sweepDegrees by sweepTransition.animateFloat(
+        initialValue = 0f,
+        targetValue = 360f,
+        animationSpec = infiniteRepeatable(tween(SWEEP_DURATION_MS, easing = LinearEasing)),
+        label = "sweepDegrees"
+    )
     val measurer = rememberTextMeasurer()
     val sunPainter = painterResource(R.drawable.ic_sun)
     val moonPainter = painterResource(R.drawable.ic_moon)
-    var sweepDegrees by remember { mutableFloatStateOf(0f) }
+    // Track path cache — keyed by both canvas size and items reference so it rebuilds
+    // when the satellite track data arrives asynchronously after the first composition
     var cachedRadius by remember { mutableFloatStateOf(0f) }
+    var cachedItemsRef by remember { mutableStateOf<List<OrbitalPos>>(emptyList()) }
+    var cachedSweepColor by remember { mutableStateOf(Color.Unspecified) }
     var trackPath by remember { mutableStateOf(Path()) }
     var trackEffect by remember { mutableStateOf(PathEffect.cornerPathEffect(0f)) }
+    // ShaderBrush is cached to avoid allocating a new GPU shader object every frame
+    var cachedSweepBrush by remember { mutableStateOf<ShaderBrush?>(null) }
 
     Canvas(modifier = modifier.aspectRatio(1f)) {
         val radius = size.minDimension / 2f * 0.95f
-        if (radius != cachedRadius) {
+        // Rebuild track path and sweep brush when canvas size or track data changes
+        if (radius != cachedRadius || items !== cachedItemsRef) {
             trackPath = createTrackPath(items, radius)
             trackEffect = createTrackEffect(trackPath)
+            cachedSweepBrush = makeSweepBrush(center, primaryColor)
             cachedRadius = radius
+            cachedItemsRef = items
+            cachedSweepColor = primaryColor
+        } else if (primaryColor != cachedSweepColor) {
+            // Rebuild brush on theme change without waiting for a size change
+            cachedSweepBrush = makeSweepBrush(center, primaryColor)
+            cachedSweepColor = primaryColor
         }
         rotate(if (shouldUseCompass) -azimElev.first else 0f) {
-            if (shouldShowSweep) drawSweep(center, sweepDegrees, radius, primaryColor)
+            if (shouldShowSweep) cachedSweepBrush?.let { drawSweep(center, sweepDegrees, radius, it) }
             drawRadar(radius, radarColor)
             drawElevationLabels(radius, primaryColor, measurer)
             translate(center.x, center.y) {
@@ -127,7 +149,6 @@ fun RadarViewCompose(
                 }
                 if (shouldUseCompass) drawAim(azimElev.first, azimElev.second, radius, aimColor)
             }
-            sweepDegrees = (sweepDegrees + SWEEP_INCREMENT) % 360f
         }
     }
 }
@@ -172,10 +193,13 @@ private fun DrawScope.drawAim(azim: Float, elev: Float, radius: Float, color: Co
     drawCircle(color, size / 2, pos, style = Stroke(STROKE_WIDTH))
 }
 
-private fun DrawScope.drawSweep(center: Offset, degrees: Float, radius: Float, color: Color) {
+private fun makeSweepBrush(center: Offset, color: Color): ShaderBrush {
     val colors = listOf(Color.Transparent, color.copy(alpha = 0.5f), color)
     val colorStops = listOf(0.64f, 0.995f, 1f)
-    val brush = ShaderBrush(SweepGradientShader(center, colors, colorStops))
+    return ShaderBrush(SweepGradientShader(center, colors, colorStops))
+}
+
+private fun DrawScope.drawSweep(center: Offset, degrees: Float, radius: Float, brush: ShaderBrush) {
     rotate(-90 + degrees, center) { drawCircle(brush, radius, style = Fill) }
 }
 

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/RadarViewModel.kt

@@ -40,6 +40,7 @@ import com.rtbishop.look4sat.core.domain.usecase.IShowToast
 import com.rtbishop.look4sat.core.domain.utility.round
 import com.rtbishop.look4sat.core.domain.utility.toDegrees
 import com.rtbishop.look4sat.core.domain.utility.toTimerString
+import com.rtbishop.look4sat.core.presentation.formatFrequency
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -48,7 +49,7 @@ import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
-import java.util.Locale
+import kotlin.time.Duration.Companion.milliseconds
 
 class RadarViewModel(
     private val bluetoothReporter: IReporter,
@@ -69,10 +70,15 @@ class RadarViewModel(
     private var sstvDecoder: SstvDecoder? = null
     private var sstvRecordingJob: Job? = null
 
+    // Celestial positions change slowly, recompute at most once per minute
+    private var lastCelestialUpdateMs = 0L
+    private var cachedSunPos: CelestialComputer.SunPosition? = null
+    private var cachedMoonPos: CelestialComputer.MoonPosition? = null
+
     private val _uiState = MutableStateFlow(
         RadarState(
             isUtc = settingsRepo.otherSettings.value.stateOfUtc,
-            orientationValues = sensorsRepo.orientation.value,
+            orientationValues = sensorsRepo.sensorData.value,
             shouldShowSweep = settingsRepo.otherSettings.value.stateOfSweep,
             shouldUseCompass = settingsRepo.otherSettings.value.stateOfSensors,
             sstv = SstvSubState(selectedMode = settingsRepo.otherSettings.value.sstvMode)
@@ -91,7 +97,7 @@ class RadarViewModel(
         if (!settingsRepo.otherSettings.value.stateOfSensors) return
         viewModelScope.launch {
             sensorsRepo.enableSensor()
-            sensorsRepo.orientation.collect { data ->
+            sensorsRepo.sensorData.collect { data ->
                 val orientationValues = (data.first + magDeclination) to data.second
                 _uiState.update { it.copy(orientationValues = orientationValues) }
             }
@@ -101,52 +107,75 @@ class RadarViewModel(
     private fun collectSettingsChanges() {
         viewModelScope.launch {
             settingsRepo.otherSettings.collectLatest { settings ->
-                _uiState.update { it.copy(isUtc = settings.stateOfUtc) }
+                _uiState.update {
+                    it.copy(
+                        isUtc = settings.stateOfUtc,
+                        shouldShowSweep = settings.stateOfSweep,
+                        shouldUseCompass = settings.stateOfSensors
+                    )
+                }
             }
         }
     }
 
+    // --- Pass loading split into focused functions ---
+
     private fun collectPassAndStartTickLoop() {
         viewModelScope.launch {
-            val passes = satelliteRepo.passes.value
-            val (catNum, aosTime) = satelliteRepo.selectedPass.value
-            val pass = passes.find { it.catNum == catNum && it.aosTime == aosTime } ?: passes.firstOrNull() ?: return@launch
-            _uiState.update { it.copy(currentPass = pass) }
-            val transmittersList = satelliteRepo.getRadiosWithId(pass.catNum)
-            transponders = transmittersList.filter { it.downlinkLow != null }
-            _uiState.update { state ->
-                state.copy(radioControl = state.radioControl.copy(transponders = transponders))
-            }
-            if (transmittersList.isNotEmpty()) {
-                val firstUuid = transmittersList.first().uuid
-                _uiState.update { it.copy(selectedTransmitterUuid = firstUuid) }
-                transponders.find { it.uuid == firstUuid }?.let { trackingService.setTransponder(it) }
-            }
-            if (!pass.isDeepSpace) {
-                val track = satelliteRepo.getTrack(pass.orbitalObject, stationPos, pass.aosTime, pass.losTime)
-                _uiState.update { it.copy(satTrack = track) }
-            }
+            val pass = findCurrentPass() ?: return@launch
+            val allRadios = loadPassData(pass)
             while (isActive) {
-                tickPass(pass, transmittersList)
-                delay(1000)
+                tickPass(pass, allRadios)
+                delay(1000.milliseconds)
             }
         }
     }
 
-    private suspend fun tickPass(pass: OrbitalPass, transmittersList: List<SatRadio>) {
+    private fun findCurrentPass(): OrbitalPass? {
+        val passes = satelliteRepo.passes.value
+        val (catNum, aosTime) = satelliteRepo.selectedPass.value
+        return passes.find { it.catNum == catNum && it.aosTime == aosTime }
+            ?: passes.firstOrNull()
+    }
+
+    // Loads transmitters and satellite track for pass, sets initial state, returns full radio list
+    private suspend fun loadPassData(pass: OrbitalPass): List<SatRadio> {
+        _uiState.update { it.copy(currentPass = pass) }
+        val allRadios = satelliteRepo.getRadiosWithId(pass.catNum)
+        transponders = allRadios.filter { it.downlinkLow != null }
+        if (allRadios.isNotEmpty()) {
+            val firstUuid = allRadios.first().uuid
+            _uiState.update { it.copy(transceivers = it.transceivers.copy(selectedUuid = firstUuid)) }
+            transponders.find { it.uuid == firstUuid }?.let { trackingService.setTransponder(it) }
+        }
+        if (!pass.isDeepSpace) {
+            val track = satelliteRepo.getTrack(pass.orbitalObject, stationPos, pass.aosTime, pass.losTime)
+            _uiState.update { it.copy(satTrack = track) }
+        }
+        return allRadios
+    }
+
+    // --- Per-second tick ---
+
+    private suspend fun tickPass(pass: OrbitalPass, allRadios: List<SatRadio>) {
         val timeNow = System.currentTimeMillis()
         val pos = satelliteRepo.getPosition(pass.orbitalObject, stationPos, timeNow)
-        val sunPos = CelestialComputer.getSunPosition(stationPos, timeNow)
-        val moonPos = CelestialComputer.getMoonPosition(stationPos, timeNow)
+
+        // Recompute celestial positions at most once per minute (they move very slowly)
+        if (timeNow - lastCelestialUpdateMs >= 60_000L) {
+            cachedSunPos = CelestialComputer.getSunPosition(stationPos, timeNow)
+            cachedMoonPos = CelestialComputer.getMoonPosition(stationPos, timeNow)
+            lastCelestialUpdateMs = timeNow
+        }
+
         val (time, isAos) = computeTimer(pass.isDeepSpace, pass.aosTime, pass.losTime, timeNow)
-        val isLos = !pass.isDeepSpace && timeNow > pass.losTime
         _uiState.update {
             it.copy(
-                currentTime = time, isTimeAos = isAos, isLos = isLos,
-                orbitalPos = pos, sunPosition = sunPos, moonPosition = moonPos
+                currentTime = time, isTimeAos = isAos,
+                orbitalPos = pos, sunPosition = cachedSunPos, moonPosition = cachedMoonPos
             )
         }
-        processRadios(transmittersList, pass.orbitalObject, timeNow)
+        processRadios(allRadios, pass.orbitalObject, timeNow)
         sendPassData(pos)
     }
 
@@ -191,24 +220,15 @@ class RadarViewModel(
         when (action) {
             is RadarAction.AddToCalendar -> addToCalendar(action.name, action.aosTime, action.losTime)
             is RadarAction.SelectTransmitter -> {
-                val previousUuid = _uiState.value.selectedTransmitterUuid
-                _uiState.update {
-                    val newUuid = if (it.selectedTransmitterUuid == action.uuid) null else action.uuid
-                    it.copy(selectedTransmitterUuid = newUuid)
+                // Compute toggle state before the update so we don't read post-update value
+                val isTogglingOff = _uiState.value.transceivers.selectedUuid == action.uuid
+                val newUuid = if (isTogglingOff) null else action.uuid
+                _uiState.update { it.copy(transceivers = it.transceivers.copy(selectedUuid = newUuid)) }
+                // Only update the tracking service when selecting a different transponder to
+                // avoid resetting a user-adjusted TX base on re-expand
+                if (!isTogglingOff) {
+                    transponders.find { it.uuid == action.uuid }?.let { trackingService.setTransponder(it) }
                 }
-                // Also set this as the active transponder for radio tracking.
-                // Always use the original (un-Dopplered) transponders list so that the
-                // TX base frequency is computed from the clean nominal values.
-                // Only update the service when selecting a *different* transponder to
-                // avoid resetting a user-adjusted TX base on re-expand.
-                val selected = transponders.find { it.uuid == action.uuid }
-                if (selected != null && _uiState.value.selectedTransmitterUuid != null && previousUuid != action.uuid) {
-                    trackingService.setTransponder(selected)
-                }
-            }
-            is RadarAction.SelectTransponder -> {
-                val transponder = transponders.find { it.uuid == action.uuid } ?: return
-                trackingService.setTransponder(transponder)
             }
             is RadarAction.SetTxFrequency -> trackingService.setTxBaseFrequency(action.frequencyHz)
             is RadarAction.AdjustTxFrequency -> trackingService.adjustTxBaseFrequency(action.deltaHz)
@@ -236,10 +256,10 @@ class RadarViewModel(
             RadarAction.SstvSaveImage -> {
                 val frame = _uiState.value.sstv.currentFrame ?: return
                 val pixels = frame.imagePixels ?: return
-                _uiState.update { it.copy(sstv = it.sstv.copy(status = SstvStatus.Saving)) }
+                _uiState.update { it.copy(sstv = it.sstv.copy(isSaving = true)) }
                 viewModelScope.launch {
                     saveImage(pixels, frame.imageWidth, frame.imageHeight, frame.modeName)
-                    _uiState.update { it.copy(sstv = it.sstv.copy(status = SstvStatus.Idle)) }
+                    _uiState.update { it.copy(sstv = it.sstv.copy(isSaving = false)) }
                     showToast("Image saved")
                 }
             }
@@ -249,7 +269,7 @@ class RadarViewModel(
                 settingsRepo.updateOtherSettings { it.copy(sstvMode = action.modeName) }
             }
             RadarAction.SstvReset -> {
-                sstvDecoder?.clearPixels() // Keep decoder alive, just reset pixels
+                sstvDecoder?.clearPixels()
                 _uiState.update { it.copy(sstv = it.sstv.copy(currentFrame = null)) }
             }
         }
@@ -285,13 +305,14 @@ class RadarViewModel(
         frequencyEnabled: Boolean,
         frequencyFormat: String
     ) {
-        if (rotatorEnabled) {
+        // Only send rotator commands when the satellite is above the horizon
+        if (rotatorEnabled && orbitalPos.aboveHorizon) {
             val azimuth = orbitalPos.azimuth.toDegrees().round(2)
             val elevation = orbitalPos.elevation.toDegrees().round(2)
             reporter.reportRotation(rotatorFormat, azimuth, elevation)
         }
         if (frequencyEnabled) {
-            _uiState.value.selectedFrequency?.let { freq ->
+            _uiState.value.transceivers.selectedFrequency?.let { freq ->
                 reporter.reportFrequency(frequencyFormat, freq)
             }
         }
@@ -299,12 +320,9 @@ class RadarViewModel(
 
     private suspend fun processRadios(radios: List<SatRadio>, orbitalObject: OrbitalObject, time: Long) {
         val transmitters = satelliteRepo.getRadios(orbitalObject, stationPos, radios, time)
-        val isFreqEnabled =
-            settingsRepo.rcSettings.value.frequencyState || settingsRepo.rcSettings.value.bluetoothFrequencyState
         _uiState.update { state ->
-            // Derive the frequency to report from the user's current selection (if any)
-            val freq = if (isFreqEnabled && state.selectedTransmitterUuid != null) {
-                val selectedRadio = transmitters.firstOrNull { it.uuid == state.selectedTransmitterUuid }
+            val freq = if (state.transceivers.selectedUuid != null) {
+                val selectedRadio = transmitters.firstOrNull { it.uuid == state.transceivers.selectedUuid }
                 selectedRadio?.let { radio ->
                     val low = radio.downlinkLow
                     val high = radio.downlinkHigh
@@ -316,10 +334,11 @@ class RadarViewModel(
                 }
             } else null
 
-            if (state.transmitters == transmitters && state.selectedFrequency == freq) {
+            val current = state.transceivers
+            if (current.transmitters == transmitters && current.selectedFrequency == freq) {
                 return@update state
             }
-            state.copy(transmitters = transmitters, selectedFrequency = freq)
+            state.copy(transceivers = current.copy(transmitters = transmitters, selectedFrequency = freq))
         }
     }
 
@@ -327,6 +346,7 @@ class RadarViewModel(
         if (sstvDecoder == null) {
             val decoder = SstvDecoder(sampleRate = audioCapture.sampleRate)
             sstvDecoder = decoder
+            decoder.lockMode(_uiState.value.sstv.selectedMode)
             _uiState.update { it.copy(sstv = it.sstv.copy(supportedModes = decoder.supportedModes)) }
             viewModelScope.launch {
                 decoder.frames.collect { frame ->
@@ -362,13 +382,6 @@ class RadarViewModel(
             218.1, 225.7, 233.6, 241.8, 250.3
         )
 
-        fun formatFrequency(frequencyHz: Long): String {
-            if (frequencyHz <= 0) return "---"
-            val mhz = frequencyHz / 1_000_000
-            val khz = (frequencyHz % 1_000_000) / 1_000
-            val hz = frequencyHz % 1_000
-            return String.format(Locale.ENGLISH, "%d.%03d.%03d", mhz, khz, hz)
-        }
 
         fun factory(container: IMainContainer) = viewModelFactory {
             initializer {

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/SstvPage.kt

@@ -55,12 +55,14 @@ import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.compose.ui.window.Dialog
 import com.rtbishop.look4sat.core.presentation.IconCard
+import com.rtbishop.look4sat.core.presentation.OutlinedText
 import com.rtbishop.look4sat.core.presentation.R
 import com.rtbishop.look4sat.core.presentation.infiniteMarquee
 
 @Composable
 internal fun SstvPage(
     sstv: SstvSubState,
+    dopplerFrequency: String?,
     onAction: (RadarAction) -> Unit,
     requestMicPermission: () -> Unit
 ) {
@@ -180,59 +182,72 @@ internal fun SstvPage(
             )
         }
         // Bottom control bar — dark, blends with the black canvas
-        Row(
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(8.dp),
+        Column(
             modifier = Modifier
                 .align(Alignment.BottomCenter)
                 .fillMaxWidth()
-                .padding(horizontal = 8.dp, vertical = 8.dp)
+                .padding(horizontal = 8.dp, vertical = 8.dp),
+            verticalArrangement = Arrangement.spacedBy(2.dp)
         ) {
-            // Mode button — opens dialog
-            ElevatedCard(
-                modifier = Modifier.weight(1f).height(48.dp),
-                onClick = { showModeDialog.value = true },
-                colors = CardDefaults.elevatedCardColors(
-                    containerColor = MaterialTheme.colorScheme.surface
-                )
+            // Doppler-corrected downlink frequency hint
+            OutlinedText(
+                text = dopplerFrequency?.let { "RX: $it Hz" } ?: "No transceiver selected",
+                fontSize = 18.sp,
+                fontWeight = FontWeight.Bold,
+                fillColor = MaterialTheme.colorScheme.primary,
+                outlineColor = MaterialTheme.colorScheme.background,
+                modifier = Modifier.align(Alignment.CenterHorizontally)
+            )
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.spacedBy(8.dp),
+                modifier = Modifier.fillMaxWidth()
             ) {
-                Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
-                    Text(
-                        text = "Mode: ${sstv.selectedMode}",
-                        fontSize = 14.sp,
-                        maxLines = 1,
-                        color = MaterialTheme.colorScheme.onSurface,
-                        modifier = Modifier.infiniteMarquee()
+                // Mode button — opens dialog
+                ElevatedCard(
+                    modifier = Modifier.weight(1f).height(48.dp),
+                    onClick = { showModeDialog.value = true },
+                    colors = CardDefaults.elevatedCardColors(
+                        containerColor = MaterialTheme.colorScheme.surface
                     )
+                ) {
+                    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+                        Text(
+                            text = "Mode: ${sstv.selectedMode}",
+                            fontSize = 14.sp,
+                            maxLines = 1,
+                            color = MaterialTheme.colorScheme.onSurface,
+                            modifier = Modifier.infiniteMarquee()
+                        )
+                    }
                 }
-            }
-            // Reset button — clears decoder state and image
-            IconCard(
-                action = { onAction(RadarAction.SstvReset) },
-                resId = R.drawable.ic_delete
-            )
-            // Save button — always visible, enabled when there are pixels
-            IconCard(
-                action = { onAction(RadarAction.SstvSaveImage) },
-                resId = R.drawable.ic_save,
-                enabled = sstv.currentFrame?.imagePixels != null
-            )
-            // Record / Stop button
-            val playAction = {
-                when (sstv.status) {
-                    SstvStatus.Idle -> onAction(RadarAction.SstvStartRecording)
-                    SstvStatus.Recording -> onAction(RadarAction.SstvStopRecording)
-                    SstvStatus.Saving -> {}
+                // Reset button — clears decoder state and image
+                IconCard(
+                    action = { onAction(RadarAction.SstvReset) },
+                    resId = R.drawable.ic_delete
+                )
+                // Save button — always visible, enabled when there are pixels
+                IconCard(
+                    action = { onAction(RadarAction.SstvSaveImage) },
+                    resId = R.drawable.ic_save,
+                    enabled = sstv.currentFrame?.imagePixels != null && !sstv.isSaving
+                )
+                // Record / Stop button
+                val playAction = {
+                    when (sstv.status) {
+                        SstvStatus.Idle -> onAction(RadarAction.SstvStartRecording)
+                        SstvStatus.Recording -> onAction(RadarAction.SstvStopRecording)
+                    }
                 }
-            }
-            val playColors = CardDefaults.elevatedCardColors(
-                containerColor = if (sstv.status == SstvStatus.Recording) MaterialTheme.colorScheme.primary
-                else MaterialTheme.colorScheme.surface
-            )
-            val playIcon = if (sstv.status == SstvStatus.Recording) R.drawable.ic_pause else R.drawable.ic_play
-            ElevatedCard(modifier = Modifier.size(48.dp), onClick = playAction, colors = playColors) {
-                Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
-                    Icon(painter = painterResource(playIcon), contentDescription = null)
+                val playColors = CardDefaults.elevatedCardColors(
+                    containerColor = if (sstv.status == SstvStatus.Recording) MaterialTheme.colorScheme.primary
+                    else MaterialTheme.colorScheme.surface
+                )
+                val playIcon = if (sstv.status == SstvStatus.Recording) R.drawable.ic_pause else R.drawable.ic_play
+                ElevatedCard(modifier = Modifier.size(48.dp), onClick = playAction, colors = playColors) {
+                    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+                        Icon(painter = painterResource(playIcon), contentDescription = null)
+                    }
                 }
             }
         }

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/TransceiversPage.kt

@@ -62,8 +62,10 @@ import androidx.compose.ui.unit.sp
 import com.rtbishop.look4sat.core.domain.model.SatRadio
 import com.rtbishop.look4sat.core.presentation.CardButton
 import com.rtbishop.look4sat.core.presentation.R
+import com.rtbishop.look4sat.core.presentation.formatFrequency
 import com.rtbishop.look4sat.core.presentation.infiniteMarquee
 import java.util.Locale
+import kotlin.time.Duration.Companion.milliseconds
 
 @Composable
 fun TransceiversPage(
@@ -82,7 +84,7 @@ fun TransceiversPage(
             if (selectedUuid != null) {
                 val index = transceivers.indexOfFirst { it.uuid == selectedUuid }
                 if (index >= 0) {
-                    kotlinx.coroutines.delay(300)
+                    kotlinx.coroutines.delay(300.milliseconds)
                     listState.animateScrollToItem(index)
                 }
             }
@@ -325,7 +327,7 @@ private fun ExpandedRadioControl(
                         color = MaterialTheme.colorScheme.onSurfaceVariant
                     )
                     Text(
-                        text = "${RadarViewModel.formatFrequency(radioControl.txBaseFrequencyHz)} MHz",
+                        text = "${formatFrequency(radioControl.txBaseFrequencyHz)} MHz",
                         fontSize = 18.sp,
                         fontWeight = FontWeight.Bold,
                         color = MaterialTheme.colorScheme.primary
@@ -335,7 +337,7 @@ private fun ExpandedRadioControl(
                 val upHigh = radio.uplinkHigh
                 if (upLow != null && upHigh != null && upLow != upHigh) {
                     Text(
-                        text = "(${RadarViewModel.formatFrequency(upLow)} – ${RadarViewModel.formatFrequency(upHigh)})",
+                        text = "(${formatFrequency(upLow)} – ${formatFrequency(upHigh)})",
                         fontSize = 12.sp,
                         color = MaterialTheme.colorScheme.onSurfaceVariant
                     )

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsScreen.kt

@@ -34,10 +34,14 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.GridItemSpan
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.ElevatedCard
+import androidx.compose.material3.ElevatedButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.LinearProgressIndicator
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
@@ -56,11 +60,13 @@ import androidx.compose.ui.platform.LocalUriHandler
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
+import com.rtbishop.look4sat.core.domain.model.MapSource
 import com.rtbishop.look4sat.core.domain.model.OtherSettings
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
@@ -91,7 +97,8 @@ private fun SettingsScreen(uiState: SettingsState, onAction: (SettingsAction) ->
     val dialogs = rememberDialogVisibility()
     val permissions = rememberSettingsPermissions(
         sendAction = onAction,
-        onBluetoothGranted = { dialogs.bluetooth = true }
+        onBluetoothGranted = { dialogs.bluetooth = true },
+        onNetworkGranted = { dialogs.network = true }
     )
 
     // Dialogs
@@ -273,12 +280,13 @@ private fun SettingsScreen(uiState: SettingsState, onAction: (SettingsAction) ->
             }
             item(span = { GridItemSpan(maxLineSpan) }) {
                 OutputCard(
-                    onNetworkClick = { dialogs.network = true },
+                    onNetworkClick = permissions.launchNetwork,
                     onBluetoothClick = permissions.launchBluetooth,
                     onRadioControlClick = { dialogs.radioControl = true }
                 )
             }
             item { OtherCard(uiState.otherSettings, onAction) }
+            item { MapSettingsCard(uiState.otherSettings, onAction) }
             item { CardCredits() }
         }
     }
@@ -461,6 +469,106 @@ private fun OtherCardPreview() = MainTheme {
     OtherCard(settings = values) {}
 }
 
+@Composable
+private fun MapSettingsCard(settings: OtherSettings, onAction: (SettingsAction) -> Unit) {
+    var keyValue by remember(settings.tiandituKey) { mutableStateOf(settings.tiandituKey) }
+    LaunchedEffect(keyValue) {
+        kotlinx.coroutines.delay(400)
+        if (keyValue.trim() != settings.tiandituKey) {
+            onAction(SettingsAction.SetTiandituKey(keyValue))
+        }
+    }
+    ElevatedCard(modifier = Modifier.fillMaxWidth()) {
+        Column(
+            horizontalAlignment = Alignment.CenterHorizontally,
+            modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp)
+        ) {
+            Text(
+                text = stringResource(id = R.string.prefs_map_title),
+                color = MaterialTheme.colorScheme.primary
+            )
+            Spacer(modifier = Modifier.height(6.dp))
+            val currentMapSource = MapSource.normalize(settings.mapSource)
+            MapSourceRow(
+                currentMapSource = currentMapSource,
+                firstSource = MapSource.OSM,
+                firstTitle = stringResource(id = R.string.prefs_map_source_osm),
+                secondSource = MapSource.TIANDITU_VECTOR,
+                secondTitle = stringResource(id = R.string.prefs_map_source_tianditu_vector),
+                onAction = onAction
+            )
+            Spacer(modifier = Modifier.height(6.dp))
+            MapSourceRow(
+                currentMapSource = currentMapSource,
+                firstSource = MapSource.TIANDITU_IMAGE,
+                firstTitle = stringResource(id = R.string.prefs_map_source_tianditu_image),
+                onAction = onAction
+            )
+            Spacer(modifier = Modifier.height(6.dp))
+            OutlinedTextField(
+                value = keyValue,
+                onValueChange = { keyValue = it },
+                label = { Text(text = stringResource(id = R.string.prefs_map_tianditu_key)) },
+                singleLine = true,
+                modifier = Modifier.fillMaxWidth()
+            )
+            Spacer(modifier = Modifier.height(6.dp))
+            CardButton(
+                onClick = { onAction(SettingsAction.SetTiandituKey(keyValue)) },
+                text = stringResource(id = R.string.prefs_map_save_key),
+                modifier = Modifier.fillMaxWidth()
+            )
+        }
+    }
+}
+
+@Composable
+private fun MapSourceRow(
+    currentMapSource: String,
+    firstSource: String,
+    firstTitle: String,
+    secondSource: String? = null,
+    secondTitle: String? = null,
+    onAction: (SettingsAction) -> Unit
+) {
+    Row(horizontalArrangement = Arrangement.spacedBy(6.dp)) {
+        MapSourceButton(
+            onClick = { onAction(SettingsAction.SetMapSource(firstSource)) },
+            text = firstTitle,
+            selected = currentMapSource == firstSource,
+            modifier = Modifier.weight(1f)
+        )
+        if (secondSource != null && secondTitle != null) {
+            MapSourceButton(
+                onClick = { onAction(SettingsAction.SetMapSource(secondSource)) },
+                text = secondTitle,
+                selected = currentMapSource == secondSource,
+                modifier = Modifier.weight(1f)
+            )
+        } else {
+            Spacer(modifier = Modifier.weight(1f))
+        }
+    }
+}
+
+@Composable
+private fun MapSourceButton(onClick: () -> Unit, text: String, selected: Boolean, modifier: Modifier = Modifier) {
+    ElevatedButton(
+        onClick = onClick,
+        colors = ButtonDefaults.buttonColors(
+            containerColor = if (selected) MaterialTheme.colorScheme.primary
+            else MaterialTheme.colorScheme.surfaceVariant,
+            contentColor = if (selected) MaterialTheme.colorScheme.onPrimary
+            else MaterialTheme.colorScheme.onSurfaceVariant
+        ),
+        shape = MaterialTheme.shapes.small,
+        modifier = modifier,
+        contentPadding = PaddingValues(horizontal = 8.dp, vertical = 8.dp)
+    ) {
+        Text(text = text, fontSize = 16.sp, textAlign = TextAlign.Center)
+    }
+}
+
 @Composable
 private fun OtherCard(settings: OtherSettings, onAction: (SettingsAction) -> Unit) {
     ElevatedCard(
@@ -651,13 +759,15 @@ private class SettingsPermissions(
     val launchLocation: () -> Unit,
     val launchTleImport: () -> Unit,
     val launchTransceiverImport: () -> Unit,
-    val launchBluetooth: () -> Unit
+    val launchBluetooth: () -> Unit,
+    val launchNetwork: () -> Unit
 )
 
 @Composable
 private fun rememberSettingsPermissions(
     sendAction: (SettingsAction) -> Unit,
-    onBluetoothGranted: () -> Unit
+    onBluetoothGranted: () -> Unit,
+    onNetworkGranted: () -> Unit
 ): SettingsPermissions {
     val locationError = stringResource(R.string.prefs_loc_gps_error)
     val locationRequest = rememberLauncherForActivityResult(
@@ -685,6 +795,12 @@ private fun rememberSettingsPermissions(
         else sendAction(SettingsAction.ShowToast(bluetoothError))
     }
 
+    val networkError = stringResource(R.string.prefs_net_perm_error)
+    val networkRequest = rememberLauncherForActivityResult(ActivityResultContracts.RequestPermission()) { granted ->
+        if (granted) onNetworkGranted()
+        else sendAction(SettingsAction.ShowToast(networkError))
+    }
+
     return remember {
         SettingsPermissions(
             launchLocation = {
@@ -694,7 +810,14 @@ private fun rememberSettingsPermissions(
             },
             launchTleImport = { tleRequest.launch("*/*") },
             launchTransceiverImport = { transceiversRequest.launch("*/*") },
-            launchBluetooth = { bluetoothRequest.launch(bluetoothPerm) }
+            launchBluetooth = { bluetoothRequest.launch(bluetoothPerm) },
+            launchNetwork = {
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.CINNAMON_BUN) {
+                    networkRequest.launch(Manifest.permission.ACCESS_LOCAL_NETWORK)
+                } else {
+                    onNetworkGranted()
+                }
+            }
         )
     }
 }

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsState.kt

@@ -61,6 +61,8 @@ sealed interface SettingsAction {
     data class ToggleSensor(val value: Boolean) : SettingsAction
     data class ToggleLightTheme(val value: Boolean) : SettingsAction
     data class ToggleNightMode(val value: Boolean) : SettingsAction
+    data class SetMapSource(val value: String) : SettingsAction
+    data class SetTiandituKey(val value: String) : SettingsAction
 
     // Remote control
     data class UpdateRC(val settings: RCSettings) : SettingsAction

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsViewModel.kt

@@ -121,6 +121,8 @@ class SettingsViewModel(
             is SettingsAction.ToggleSensor -> settingsRepo.updateOtherSettings { it.copy(stateOfSensors = action.value) }
             is SettingsAction.ToggleLightTheme -> settingsRepo.updateOtherSettings { it.copy(stateOfLightTheme = action.value) }
             is SettingsAction.ToggleNightMode -> settingsRepo.updateOtherSettings { it.copy(stateOfNightMode = action.value) }
+            is SettingsAction.SetMapSource -> settingsRepo.updateOtherSettings { it.copy(mapSource = action.value) }
+            is SettingsAction.SetTiandituKey -> settingsRepo.updateOtherSettings { it.copy(tiandituKey = action.value.trim()) }
             // Remote control & data sources
             is SettingsAction.UpdateRC -> settingsRepo.updateRCSettings(action.settings)
             is SettingsAction.UpdateRadioControl -> settingsRepo.updateRadioControlSettings(action.settings)

gradle.properties

@@ -3,3 +3,6 @@ org.gradle.caching=true
 org.gradle.jvmargs=-Xmx6g -XX:MaxMetaspaceSize=1g -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
 org.gradle.parallel=true
 org.gradle.workers.max=4
+
+# Enabled parallel sync for Gradle 9.4+
+org.gradle.tooling.parallel=true

gradle/libs.versions.toml

@@ -1,35 +1,35 @@
 [versions]
 #noinspection UnusedVersionCatalogEntry
-appVersionCode = "440"
+appVersionCode = "443"
 #noinspection UnusedVersionCatalogEntry
-appVersionName = "4.4.0"
-#noinspection GradleDependency,UnusedVersionCatalogEntry
-compileSdk = "36"
+appVersionName = "4.4.3"
+#noinspection UnusedVersionCatalogEntry
+compileSdk = "37"
 #noinspection UnusedVersionCatalogEntry
 minSdk = "24"
 #noinspection UnusedVersionCatalogEntry
-jdkVersion = "17"
+jdkVersion = "21"
 #noinspection UnusedVersionCatalogEntry
-packageName = "com.rtbishop.look4sat"
+packageName = "cn.bh2vsq.look4sat"
 
 android-gradle-plugin = "9.2.1"
 
-androidx-core-ktx = "1.18.0"
+androidx-core-ktx = "1.19.0"
 androidx-core-splashscreen = "1.2.0"
 androidx-room = "2.8.4"
 
-compose-bom = "2026.05.01"
+compose-bom = "2026.06.00"
 compose-activity = "1.13.0"
-compose-lifecycle = "2.10.0"
-compose-navigation3 = "1.1.2"
+compose-lifecycle = "2.11.0"
+compose-navigation3 = "1.1.3"
 
-google-ksp = "2.3.7"
+google-ksp = "2.3.8"
 
-kotlin = "2.3.21"
+kotlin = "2.4.0"
 kotlin-coroutines = "1.11.0"
 kotlin-serialization = "1.11.0"
 
-other-okhttp = "5.3.2"
+other-okhttp = "5.4.0"
 other-osmdroid = "6.1.20"
 
 test-junit4 = "4.13.2"

gradle/wrapper/gradle-wrapper.properties

@@ -1,7 +1,7 @@
-#Mon May 25 11:20:48 BST 2026
+#Sat Jun 27 12:51:12 BST 2026
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.1-bin.zip
+distributionUrl=https\://mirrors.aliyun.com/gradle/distributions/v9.6.1/gradle-9.6.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME