diff --git a/app/src/main/java/com/rtbishop/lookingsat/MainViewModel.kt b/app/src/main/java/com/rtbishop/lookingsat/MainViewModel.kt
index ea9534b8..61a0d876 100644
--- a/app/src/main/java/com/rtbishop/lookingsat/MainViewModel.kt
+++ b/app/src/main/java/com/rtbishop/lookingsat/MainViewModel.kt
@@ -27,12 +27,15 @@ import javax.inject.Inject
 
 class MainViewModel(application: Application) : AndroidViewModel(application) {
 
-    private val keyLat = "latitude"
-    private val keyLon = "longitude"
-    private val keyAlt = "altitude"
-    private val keyHours = "hoursAhead"
-    private val keyMaxEl = "maxElevation"
-    private val tleFileName = "tleFile.txt"
+    private val defValueLoc = application.getString(R.string.def_gsp_loc)
+    private val defValueHours = application.getString(R.string.def_hours_ahead)
+    private val defValueMinEl = application.getString(R.string.def_min_el)
+    private val keyLat = application.getString(R.string.key_lat)
+    private val keyLon = application.getString(R.string.key_lon)
+    private val keyAlt = application.getString(R.string.key_alt)
+    private val keyHours = application.getString(R.string.key_hours_ahead)
+    private val keyMinEl = application.getString(R.string.key_min_el)
+    private val tleFileName = application.getString(R.string.tle_file_name)
 
     @Inject
     lateinit var locationClient: FusedLocationProviderClient
@@ -48,9 +51,9 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
     val debugMessage = MutableLiveData("")
     val gsp = MutableLiveData<GroundStationPosition>(
         GroundStationPosition(
-            preferences.getDouble(keyLat, 0.0),
-            preferences.getDouble(keyLon, 0.0),
-            preferences.getDouble(keyAlt, 0.0)
+            preferences.getString(keyLat, defValueLoc)!!.toDouble(),
+            preferences.getString(keyLon, defValueLoc)!!.toDouble(),
+            preferences.getString(keyAlt, defValueLoc)!!.toDouble()
         )
     )
 
@@ -58,8 +61,8 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
     var tleMainList = loadTwoLineElementFile()
     var tleSelectedMap = mutableMapOf<TLE, Boolean>()
     var passPrefs = SatPassPrefs(
-        preferences.getInt(keyHours, 8),
-        preferences.getDouble(keyMaxEl, 16.0)
+        preferences.getString(keyHours, defValueHours)!!.toInt(),
+        preferences.getString(keyMinEl, defValueMinEl)!!.toDouble()
     )
 
     private fun loadTwoLineElementFile(): List<TLE> {
@@ -102,11 +105,25 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
         passPrefs = SatPassPrefs(hoursAhead, maxEl)
         preferences.edit {
             putInt(keyHours, hoursAhead)
-            putDouble(keyMaxEl, maxEl)
+            putLong(keyMinEl, maxEl.toRawBits())
             apply()
         }
     }
 
+    fun updateGsp() {
+        val lat = preferences.getString(keyLat, defValueLoc)!!.toDouble()
+        val lon = preferences.getString(keyLon, defValueLoc)!!.toDouble()
+        val alt = preferences.getString(keyAlt, defValueLoc)!!.toDouble()
+        gsp.postValue(GroundStationPosition(lat, lon, alt))
+    }
+
+    fun updatePassPref() {
+        passPrefs = SatPassPrefs(
+            preferences.getString(keyHours, defValueHours)!!.toInt(),
+            preferences.getString(keyMinEl, defValueMinEl)!!.toDouble()
+        )
+    }
+
     fun updateLocation() {
         locationClient.lastLocation.addOnSuccessListener { location: Location? ->
             val lat = location?.latitude ?: 0.0
@@ -114,9 +131,9 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
             val alt = location?.altitude ?: 0.0
 
             preferences.edit {
-                putDouble(keyLat, lat)
-                putDouble(keyLon, lon)
-                putDouble(keyAlt, alt)
+                putString(keyLat, lat.toString())
+                putString(keyLon, lon.toString())
+                putString(keyAlt, alt.toString())
                 apply()
             }
             gsp.postValue(GroundStationPosition(lat, lon, alt))
@@ -154,10 +171,4 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
     suspend fun getTransmittersForSat(id: Int): List<Transmitter> {
         return repository.getTransmittersForSat(id)
     }
-}
-
-fun SharedPreferences.Editor.putDouble(key: String, double: Double)
-        : SharedPreferences.Editor = putLong(key, double.toRawBits())
-
-fun SharedPreferences.getDouble(key: String, default: Double) =
-    Double.fromBits(getLong(key, default.toRawBits()))
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/rtbishop/lookingsat/ui/SettingsFragment.kt b/app/src/main/java/com/rtbishop/lookingsat/ui/SettingsFragment.kt
index ff1844e6..c230cb14 100644
--- a/app/src/main/java/com/rtbishop/lookingsat/ui/SettingsFragment.kt
+++ b/app/src/main/java/com/rtbishop/lookingsat/ui/SettingsFragment.kt
@@ -1,11 +1,54 @@
 package com.rtbishop.lookingsat.ui
 
+import android.content.SharedPreferences
 import android.os.Bundle
+import androidx.lifecycle.ViewModelProvider
+import androidx.preference.EditTextPreference
 import androidx.preference.PreferenceFragmentCompat
+import com.rtbishop.lookingsat.MainViewModel
 import com.rtbishop.lookingsat.R
 
-class SettingsFragment : PreferenceFragmentCompat() {
+class SettingsFragment : PreferenceFragmentCompat(),
+    SharedPreferences.OnSharedPreferenceChangeListener {
+
+    private lateinit var viewModel: MainViewModel
+
     override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
         setPreferencesFromResource(R.xml.preference, rootKey)
+
+        viewModel = ViewModelProvider(activity as MainActivity).get(MainViewModel::class.java)
+
+        val provider = EditTextPreference.SimpleSummaryProvider.getInstance()
+        val latPref = findPreference<EditTextPreference>(context!!.getText(R.string.key_lat))
+        val lonPref = findPreference<EditTextPreference>(context!!.getText(R.string.key_lon))
+        val altPref = findPreference<EditTextPreference>(context!!.getText(R.string.key_alt))
+
+        latPref?.summaryProvider = provider
+        lonPref?.summaryProvider = provider
+        altPref?.summaryProvider = provider
+    }
+
+    override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences?, key: String?) {
+        if (key == context!!.getText(R.string.key_lat) ||
+            key == context!!.getText(R.string.key_lon) ||
+            key == context!!.getText(R.string.key_alt)
+        ) {
+            viewModel.updateGsp()
+        }
+        if (key == context!!.getText(R.string.key_hours_ahead) ||
+            key == context!!.getText(R.string.key_min_el)
+        ) {
+            viewModel.updatePassPref()
+        }
+    }
+
+    override fun onResume() {
+        super.onResume()
+        preferenceManager.sharedPreferences.registerOnSharedPreferenceChangeListener(this)
+    }
+
+    override fun onPause() {
+        super.onPause()
+        preferenceManager.sharedPreferences.unregisterOnSharedPreferenceChangeListener(this)
     }
 }
\ No newline at end of file
diff --git a/app/src/main/res/layout/sat_pass_pref.xml b/app/src/main/res/layout/sat_pass_pref.xml
index b0034939..26a1d910 100644
--- a/app/src/main/res/layout/sat_pass_pref.xml
+++ b/app/src/main/res/layout/sat_pass_pref.xml
@@ -10,7 +10,7 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginTop="8dp"
-        android:text="@string/pass_pref_tv_hours"
+        android:text="@string/pref_hours_ahead_title"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
@@ -19,7 +19,7 @@
         android:id="@+id/pass_pref_et_hours"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
-        android:hint="@string/pass_pref_hint_hours"
+        android:hint="@string/pref_hours_ahead_title"
         android:importantForAutofill="no"
         android:inputType="number"
         app:layout_constraintEnd_toEndOf="@+id/pass_pref_tv_hours"
@@ -31,7 +31,7 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginTop="8dp"
-        android:text="@string/pass_pref_tv_maxEl"
+        android:text="@string/pref_min_el_title"
         app:layout_constraintEnd_toEndOf="@+id/pass_pref_et_hours"
         app:layout_constraintStart_toStartOf="@+id/pass_pref_et_hours"
         app:layout_constraintTop_toBottomOf="@+id/pass_pref_et_hours" />
@@ -40,7 +40,7 @@
         android:id="@+id/pass_pref_et_maxEl"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
-        android:hint="@string/pass_pref_hint_maxEl"
+        android:hint="@string/pref_min_el_title"
         android:importantForAutofill="no"
         android:inputType="numberDecimal"
         app:layout_constraintEnd_toEndOf="@+id/pass_pref_tv_maxEl"
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index b69c84f1..7743899c 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -39,10 +39,31 @@
     <string name="title_pass_pref">Passes preferences</string>
     <string name="title_select_sat">Select satellites to track</string>
 
-    <string name="pass_pref_tv_hours">Show passes that occur within X hours</string>
-    <string name="pass_pref_hint_hours">Hours ahead</string>
-    <string name="pass_pref_tv_maxEl">Show passes with max elevation above</string>
-    <string name="pass_pref_hint_maxEl">Max elevation</string>
+    <string name="pref_gsp_title">Ground station position settings</string>
+    <string name="pref_lat_title">Latitude</string>
+    <string name="pref_lon_title">Longitude</string>
+    <string name="pref_alt_title">Altitude</string>
+    <string name="pref_sat_pass_title">Satellite pass settings</string>
+    <string name="pref_hours_ahead_title">Hours ahead</string>
+    <string name="pref_hours_ahead_summary">Show passes that occur within X hours</string>
+    <string name="pref_min_el_title">Minimum elevation</string>
+    <string name="pref_min_el_summary">Show passes with max elevation above</string>
+    <string name="pref_other_title">Other settings</string>
+    <string name="pref_update_freq_title">Update frequency</string>
+    <string name="pref_update_freq_summary">Views update interval, ms</string>
+
+    <string name="def_gsp_loc">0.0</string>
+    <string name="def_hours_ahead">8</string>
+    <string name="def_min_el">16.0</string>
+    <string name="def_update_freq">3000</string>
+
+    <string name="key_lat">latitude</string>
+    <string name="key_lon">longitude</string>
+    <string name="key_alt">altitude</string>
+    <string name="key_hours_ahead">hours_ahead</string>
+    <string name="key_min_el">min_elevation</string>
+    <string name="key_update_freq">update_freq</string>
+    <string name="tle_file_name">tleFile.txt</string>
 
     <string name="no">No</string>
     <string name="yes">Yes</string>
diff --git a/app/src/main/res/xml/preference.xml b/app/src/main/res/xml/preference.xml
index e968c100..d8601728 100644
--- a/app/src/main/res/xml/preference.xml
+++ b/app/src/main/res/xml/preference.xml
@@ -1,48 +1,48 @@
 <?xml version="1.0" encoding="utf-8"?>
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
-    <PreferenceCategory android:title="Ground station location settings">
+    <PreferenceCategory android:title="@string/pref_gsp_title">
         <EditTextPreference
-            android:defaultValue="0.0"
-            android:key="lat"
+            android:defaultValue="@string/def_gsp_loc"
+            android:key="@string/key_lat"
             android:selectAllOnFocus="true"
             android:singleLine="true"
-            android:title="Latitude" />
+            android:title="@string/pref_lat_title" />
         <EditTextPreference
-            android:defaultValue="0.0"
-            android:key="lon"
+            android:defaultValue="@string/def_gsp_loc"
+            android:key="@string/key_lon"
             android:selectAllOnFocus="true"
             android:singleLine="true"
-            android:title="Longitude" />
+            android:title="@string/pref_lon_title" />
         <EditTextPreference
-            android:defaultValue="0.0"
-            android:key="alt"
+            android:defaultValue="@string/def_gsp_loc"
+            android:key="@string/key_alt"
             android:selectAllOnFocus="true"
             android:singleLine="true"
-            android:title="Altitude" />
+            android:title="@string/pref_alt_title" />
     </PreferenceCategory>
-    <PreferenceCategory android:title="Satellite pass settings">
+    <PreferenceCategory android:title="@string/pref_sat_pass_title">
         <EditTextPreference
-            android:defaultValue="8"
-            android:key="hours"
+            android:defaultValue="@string/def_hours_ahead"
+            android:key="@string/key_hours_ahead"
             android:selectAllOnFocus="true"
             android:singleLine="true"
-            android:summary="Show passes that occur within this time window"
-            android:title="Hours ahead" />
+            android:summary="@string/pref_hours_ahead_summary"
+            android:title="@string/pref_hours_ahead_title" />
         <EditTextPreference
-            android:defaultValue="16"
-            android:key="minEl"
+            android:defaultValue="@string/def_hours_ahead"
+            android:key="@string/key_min_el"
             android:selectAllOnFocus="true"
             android:singleLine="true"
-            android:summary="Show passes with maximum elevation above"
-            android:title="Minimum elevation" />
+            android:summary="@string/pref_min_el_summary"
+            android:title="@string/pref_min_el_title" />
     </PreferenceCategory>
-    <PreferenceCategory android:title="Other settings">
+    <PreferenceCategory android:title="@string/pref_other_title">
         <EditTextPreference
-            android:defaultValue="3000"
-            android:key="updateFreq"
+            android:defaultValue="@string/def_update_freq"
+            android:key="@string/key_update_freq"
             android:selectAllOnFocus="true"
             android:singleLine="true"
-            android:summary="RadarView and MapView update frequency, ms"
-            android:title="View update interval" />
+            android:summary="@string/pref_update_freq_summary"
+            android:title="@string/pref_update_freq_title" />
     </PreferenceCategory>
 </PreferenceScreen>
\ No newline at end of file