diff --git a/api/current.txt b/api/current.txt
index 18388b2..1c988dc 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -19214,7 +19214,7 @@
     field public static final int ADR_STATE_VALID = 1; // 0x1
     field public static final android.os.Parcelable.Creator<android.location.GnssMeasurement> CREATOR;
     field public static final int MULTIPATH_INDICATOR_DETECTED = 1; // 0x1
-    field public static final int MULTIPATH_INDICATOR_NOT_USED = 2; // 0x2
+    field public static final int MULTIPATH_INDICATOR_NOT_DETECTED = 2; // 0x2
     field public static final int MULTIPATH_INDICATOR_UNKNOWN = 0; // 0x0
     field public static final int STATE_BDS_D2_BIT_SYNC = 256; // 0x100
     field public static final int STATE_BDS_D2_SUBFRAME_SYNC = 512; // 0x200
@@ -19234,21 +19234,20 @@
   }
 
   public final class GnssMeasurementsEvent implements android.os.Parcelable {
-    ctor public GnssMeasurementsEvent(android.location.GnssClock, android.location.GnssMeasurement[]);
     method public int describeContents();
     method public android.location.GnssClock getClock();
     method public java.util.Collection<android.location.GnssMeasurement> getMeasurements();
     method public void writeToParcel(android.os.Parcel, int);
     field public static final android.os.Parcelable.Creator<android.location.GnssMeasurementsEvent> CREATOR;
-    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
-    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
-    field public static final int STATUS_READY = 1; // 0x1
   }
 
   public static abstract class GnssMeasurementsEvent.Callback {
     ctor public GnssMeasurementsEvent.Callback();
     method public void onGnssMeasurementsReceived(android.location.GnssMeasurementsEvent);
     method public void onStatusChanged(int);
+    field public static final int STATUS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
   }
 
   public final class GnssNavigationMessage implements android.os.Parcelable {
@@ -19276,36 +19275,24 @@
     field public static final int TYPE_UNKNOWN = 0; // 0x0
   }
 
-  public final class GnssNavigationMessageEvent implements android.os.Parcelable {
-    ctor public GnssNavigationMessageEvent(android.location.GnssNavigationMessage);
-    method public int describeContents();
-    method public android.location.GnssNavigationMessage getNavigationMessage();
-    method public void writeToParcel(android.os.Parcel, int);
-    field public static final android.os.Parcelable.Creator<android.location.GnssNavigationMessageEvent> CREATOR;
-    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+  public static abstract class GnssNavigationMessage.Callback {
+    ctor public GnssNavigationMessage.Callback();
+    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessage);
+    method public void onStatusChanged(int);
+    field public static final int STATUS_LOCATION_DISABLED = 2; // 0x2
     field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
     field public static final int STATUS_READY = 1; // 0x1
   }
 
-  public static abstract class GnssNavigationMessageEvent.Callback {
-    ctor public GnssNavigationMessageEvent.Callback();
-    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessageEvent);
-    method public void onStatusChanged(int);
-  }
-
-  public abstract interface GnssNmeaListener {
-    method public abstract void onNmeaReceived(long, java.lang.String);
-  }
-
   public final class GnssStatus {
     method public float getAzimuthDegrees(int);
     method public float getCn0DbHz(int);
     method public int getConstellationType(int);
     method public float getElevationDegrees(int);
-    method public int getNumSatellites();
+    method public int getSatelliteCount();
     method public int getSvid(int);
-    method public boolean hasAlmanac(int);
-    method public boolean hasEphemeris(int);
+    method public boolean hasAlmanacData(int);
+    method public boolean hasEphemerisData(int);
     method public boolean usedInFix(int);
     field public static final int CONSTELLATION_BEIDOU = 5; // 0x5
     field public static final int CONSTELLATION_GALILEO = 6; // 0x6
@@ -19316,15 +19303,15 @@
     field public static final int CONSTELLATION_UNKNOWN = 0; // 0x0
   }
 
-  public abstract class GnssStatusCallback {
-    ctor public GnssStatusCallback();
+  public static abstract class GnssStatus.Callback {
+    ctor public GnssStatus.Callback();
     method public void onFirstFix(int);
     method public void onSatelliteStatusChanged(android.location.GnssStatus);
     method public void onStarted();
     method public void onStopped();
   }
 
-  public final class GpsSatellite {
+  public final deprecated class GpsSatellite {
     method public float getAzimuth();
     method public float getElevation();
     method public int getPrn();
@@ -19334,7 +19321,7 @@
     method public boolean usedInFix();
   }
 
-  public final class GpsStatus {
+  public final deprecated class GpsStatus {
     method public int getMaxSatellites();
     method public java.lang.Iterable<android.location.GpsSatellite> getSatellites();
     method public int getTimeToFirstFix();
@@ -19344,11 +19331,11 @@
     field public static final int GPS_EVENT_STOPPED = 2; // 0x2
   }
 
-  public static abstract interface GpsStatus.Listener {
+  public static abstract deprecated interface GpsStatus.Listener {
     method public abstract void onGpsStatusChanged(int);
   }
 
-  public static abstract interface GpsStatus.NmeaListener {
+  public static abstract deprecated interface GpsStatus.NmeaListener {
     method public abstract void onNmeaReceived(long, java.lang.String);
   }
 
@@ -19410,8 +19397,8 @@
   public class LocationManager {
     method public deprecated boolean addGpsStatusListener(android.location.GpsStatus.Listener);
     method public deprecated boolean addNmeaListener(android.location.GpsStatus.NmeaListener);
-    method public boolean addNmeaListener(android.location.GnssNmeaListener);
-    method public boolean addNmeaListener(android.location.GnssNmeaListener, android.os.Handler);
+    method public boolean addNmeaListener(android.location.OnNmeaMessageListener);
+    method public boolean addNmeaListener(android.location.OnNmeaMessageListener, android.os.Handler);
     method public void addProximityAlert(double, double, float, long, android.app.PendingIntent);
     method public void addTestProvider(java.lang.String, boolean, boolean, boolean, boolean, boolean, boolean, boolean, int, int);
     method public void clearTestProviderEnabled(java.lang.String);
@@ -19427,13 +19414,13 @@
     method public boolean isProviderEnabled(java.lang.String);
     method public boolean registerGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback);
     method public boolean registerGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback, android.os.Handler);
-    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
-    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback, android.os.Handler);
-    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback);
-    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback, android.os.Handler);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback, android.os.Handler);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatus.Callback);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatus.Callback, android.os.Handler);
     method public deprecated void removeGpsStatusListener(android.location.GpsStatus.Listener);
     method public deprecated void removeNmeaListener(android.location.GpsStatus.NmeaListener);
-    method public void removeNmeaListener(android.location.GnssNmeaListener);
+    method public void removeNmeaListener(android.location.OnNmeaMessageListener);
     method public void removeProximityAlert(android.app.PendingIntent);
     method public void removeTestProvider(java.lang.String);
     method public void removeUpdates(android.location.LocationListener);
@@ -19452,8 +19439,8 @@
     method public void setTestProviderLocation(java.lang.String, android.location.Location);
     method public void setTestProviderStatus(java.lang.String, int, android.os.Bundle, long);
     method public void unregisterGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback);
-    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
-    method public void unregisterGnssStatusCallback(android.location.GnssStatusCallback);
+    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback);
+    method public void unregisterGnssStatusCallback(android.location.GnssStatus.Callback);
     field public static final java.lang.String GPS_PROVIDER = "gps";
     field public static final java.lang.String KEY_LOCATION_CHANGED = "location";
     field public static final java.lang.String KEY_PROVIDER_ENABLED = "providerEnabled";
@@ -19482,6 +19469,10 @@
     field public static final int TEMPORARILY_UNAVAILABLE = 1; // 0x1
   }
 
+  public abstract interface OnNmeaMessageListener {
+    method public abstract void onNmeaMessage(java.lang.String, long);
+  }
+
   public abstract class SettingInjectorService extends android.app.Service {
     ctor public SettingInjectorService(java.lang.String);
     method public final android.os.IBinder onBind(android.content.Intent);
diff --git a/api/removed.txt b/api/removed.txt
index 3f16bca..8c6abdc 100644
--- a/api/removed.txt
+++ b/api/removed.txt
@@ -84,6 +84,67 @@
 
 }
 
+package android.location {
+
+  public final class GnssMeasurement implements android.os.Parcelable {
+    field public static final int MULTIPATH_INDICATOR_NOT_USED = 2; // 0x2
+  }
+
+  public final class GnssMeasurementsEvent implements android.os.Parcelable {
+    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
+  }
+
+  public final class GnssNavigationMessageEvent implements android.os.Parcelable {
+    ctor public GnssNavigationMessageEvent(android.location.GnssNavigationMessage);
+    method public int describeContents();
+    method public android.location.GnssNavigationMessage getNavigationMessage();
+    method public void writeToParcel(android.os.Parcel, int);
+    field public static final android.os.Parcelable.Creator<android.location.GnssNavigationMessageEvent> CREATOR;
+    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
+  }
+
+  public static abstract class GnssNavigationMessageEvent.Callback {
+    ctor public GnssNavigationMessageEvent.Callback();
+    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessageEvent);
+    method public void onStatusChanged(int);
+  }
+
+  public abstract interface GnssNmeaListener {
+    method public abstract void onNmeaReceived(long, java.lang.String);
+  }
+
+  public final class GnssStatus {
+    method public int getNumSatellites();
+    method public boolean hasAlmanac(int);
+    method public boolean hasEphemeris(int);
+  }
+
+  public abstract class GnssStatusCallback {
+    ctor public GnssStatusCallback();
+    method public void onFirstFix(int);
+    method public void onSatelliteStatusChanged(android.location.GnssStatus);
+    method public void onStarted();
+    method public void onStopped();
+  }
+
+  public class LocationManager {
+    method public boolean addNmeaListener(android.location.GnssNmeaListener);
+    method public boolean addNmeaListener(android.location.GnssNmeaListener, android.os.Handler);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback, android.os.Handler);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback, android.os.Handler);
+    method public void removeNmeaListener(android.location.GnssNmeaListener);
+    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
+    method public void unregisterGnssStatusCallback(android.location.GnssStatusCallback);
+  }
+
+}
+
 package android.media {
 
   public final class AudioFormat implements android.os.Parcelable {
diff --git a/api/system-current.txt b/api/system-current.txt
index 051ed04..c4b074b 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -20374,7 +20374,7 @@
     field public static final int ADR_STATE_VALID = 1; // 0x1
     field public static final android.os.Parcelable.Creator<android.location.GnssMeasurement> CREATOR;
     field public static final int MULTIPATH_INDICATOR_DETECTED = 1; // 0x1
-    field public static final int MULTIPATH_INDICATOR_NOT_USED = 2; // 0x2
+    field public static final int MULTIPATH_INDICATOR_NOT_DETECTED = 2; // 0x2
     field public static final int MULTIPATH_INDICATOR_UNKNOWN = 0; // 0x0
     field public static final int STATE_BDS_D2_BIT_SYNC = 256; // 0x100
     field public static final int STATE_BDS_D2_SUBFRAME_SYNC = 512; // 0x200
@@ -20394,21 +20394,20 @@
   }
 
   public final class GnssMeasurementsEvent implements android.os.Parcelable {
-    ctor public GnssMeasurementsEvent(android.location.GnssClock, android.location.GnssMeasurement[]);
     method public int describeContents();
     method public android.location.GnssClock getClock();
     method public java.util.Collection<android.location.GnssMeasurement> getMeasurements();
     method public void writeToParcel(android.os.Parcel, int);
     field public static final android.os.Parcelable.Creator<android.location.GnssMeasurementsEvent> CREATOR;
-    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
-    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
-    field public static final int STATUS_READY = 1; // 0x1
   }
 
   public static abstract class GnssMeasurementsEvent.Callback {
     ctor public GnssMeasurementsEvent.Callback();
     method public void onGnssMeasurementsReceived(android.location.GnssMeasurementsEvent);
     method public void onStatusChanged(int);
+    field public static final int STATUS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
   }
 
   public final class GnssNavigationMessage implements android.os.Parcelable {
@@ -20436,36 +20435,24 @@
     field public static final int TYPE_UNKNOWN = 0; // 0x0
   }
 
-  public final class GnssNavigationMessageEvent implements android.os.Parcelable {
-    ctor public GnssNavigationMessageEvent(android.location.GnssNavigationMessage);
-    method public int describeContents();
-    method public android.location.GnssNavigationMessage getNavigationMessage();
-    method public void writeToParcel(android.os.Parcel, int);
-    field public static final android.os.Parcelable.Creator<android.location.GnssNavigationMessageEvent> CREATOR;
-    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+  public static abstract class GnssNavigationMessage.Callback {
+    ctor public GnssNavigationMessage.Callback();
+    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessage);
+    method public void onStatusChanged(int);
+    field public static final int STATUS_LOCATION_DISABLED = 2; // 0x2
     field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
     field public static final int STATUS_READY = 1; // 0x1
   }
 
-  public static abstract class GnssNavigationMessageEvent.Callback {
-    ctor public GnssNavigationMessageEvent.Callback();
-    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessageEvent);
-    method public void onStatusChanged(int);
-  }
-
-  public abstract interface GnssNmeaListener {
-    method public abstract void onNmeaReceived(long, java.lang.String);
-  }
-
   public final class GnssStatus {
     method public float getAzimuthDegrees(int);
     method public float getCn0DbHz(int);
     method public int getConstellationType(int);
     method public float getElevationDegrees(int);
-    method public int getNumSatellites();
+    method public int getSatelliteCount();
     method public int getSvid(int);
-    method public boolean hasAlmanac(int);
-    method public boolean hasEphemeris(int);
+    method public boolean hasAlmanacData(int);
+    method public boolean hasEphemerisData(int);
     method public boolean usedInFix(int);
     field public static final int CONSTELLATION_BEIDOU = 5; // 0x5
     field public static final int CONSTELLATION_GALILEO = 6; // 0x6
@@ -20476,8 +20463,8 @@
     field public static final int CONSTELLATION_UNKNOWN = 0; // 0x0
   }
 
-  public abstract class GnssStatusCallback {
-    ctor public GnssStatusCallback();
+  public static abstract class GnssStatus.Callback {
+    ctor public GnssStatus.Callback();
     method public void onFirstFix(int);
     method public void onSatelliteStatusChanged(android.location.GnssStatus);
     method public void onStarted();
@@ -20709,7 +20696,7 @@
     method public abstract void onStatusChanged(int);
   }
 
-  public final class GpsSatellite {
+  public final deprecated class GpsSatellite {
     method public float getAzimuth();
     method public float getElevation();
     method public int getPrn();
@@ -20719,7 +20706,7 @@
     method public boolean usedInFix();
   }
 
-  public final class GpsStatus {
+  public final deprecated class GpsStatus {
     method public int getMaxSatellites();
     method public java.lang.Iterable<android.location.GpsSatellite> getSatellites();
     method public int getTimeToFirstFix();
@@ -20729,11 +20716,11 @@
     field public static final int GPS_EVENT_STOPPED = 2; // 0x2
   }
 
-  public static abstract interface GpsStatus.Listener {
+  public static abstract deprecated interface GpsStatus.Listener {
     method public abstract void onGpsStatusChanged(int);
   }
 
-  public static abstract interface GpsStatus.NmeaListener {
+  public static abstract deprecated interface GpsStatus.NmeaListener {
     method public abstract void onNmeaReceived(long, java.lang.String);
   }
 
@@ -20817,8 +20804,8 @@
     method public deprecated boolean addGpsNavigationMessageListener(android.location.GpsNavigationMessageEvent.Listener);
     method public deprecated boolean addGpsStatusListener(android.location.GpsStatus.Listener);
     method public deprecated boolean addNmeaListener(android.location.GpsStatus.NmeaListener);
-    method public boolean addNmeaListener(android.location.GnssNmeaListener);
-    method public boolean addNmeaListener(android.location.GnssNmeaListener, android.os.Handler);
+    method public boolean addNmeaListener(android.location.OnNmeaMessageListener);
+    method public boolean addNmeaListener(android.location.OnNmeaMessageListener, android.os.Handler);
     method public void addProximityAlert(double, double, float, long, android.app.PendingIntent);
     method public void addTestProvider(java.lang.String, boolean, boolean, boolean, boolean, boolean, boolean, boolean, int, int);
     method public void clearTestProviderEnabled(java.lang.String);
@@ -20834,15 +20821,15 @@
     method public boolean isProviderEnabled(java.lang.String);
     method public boolean registerGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback);
     method public boolean registerGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback, android.os.Handler);
-    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
-    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback, android.os.Handler);
-    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback);
-    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback, android.os.Handler);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback, android.os.Handler);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatus.Callback);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatus.Callback, android.os.Handler);
     method public deprecated void removeGpsMeasurementListener(android.location.GpsMeasurementsEvent.Listener);
     method public deprecated void removeGpsNavigationMessageListener(android.location.GpsNavigationMessageEvent.Listener);
     method public deprecated void removeGpsStatusListener(android.location.GpsStatus.Listener);
     method public deprecated void removeNmeaListener(android.location.GpsStatus.NmeaListener);
-    method public void removeNmeaListener(android.location.GnssNmeaListener);
+    method public void removeNmeaListener(android.location.OnNmeaMessageListener);
     method public void removeProximityAlert(android.app.PendingIntent);
     method public void removeTestProvider(java.lang.String);
     method public void removeUpdates(android.location.LocationListener);
@@ -20863,8 +20850,8 @@
     method public void setTestProviderLocation(java.lang.String, android.location.Location);
     method public void setTestProviderStatus(java.lang.String, int, android.os.Bundle, long);
     method public void unregisterGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback);
-    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
-    method public void unregisterGnssStatusCallback(android.location.GnssStatusCallback);
+    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback);
+    method public void unregisterGnssStatusCallback(android.location.GnssStatus.Callback);
     field public static final java.lang.String GPS_PROVIDER = "gps";
     field public static final java.lang.String KEY_LOCATION_CHANGED = "location";
     field public static final java.lang.String KEY_PROVIDER_ENABLED = "providerEnabled";
@@ -20927,6 +20914,10 @@
     field public static final int POWER_NONE = 200; // 0xc8
   }
 
+  public abstract interface OnNmeaMessageListener {
+    method public abstract void onNmeaMessage(java.lang.String, long);
+  }
+
   public abstract class SettingInjectorService extends android.app.Service {
     ctor public SettingInjectorService(java.lang.String);
     method public final android.os.IBinder onBind(android.content.Intent);
diff --git a/api/system-removed.txt b/api/system-removed.txt
index 03cf8b0..95734c1 100644
--- a/api/system-removed.txt
+++ b/api/system-removed.txt
@@ -82,6 +82,67 @@
 
 }
 
+package android.location {
+
+  public final class GnssMeasurement implements android.os.Parcelable {
+    field public static final int MULTIPATH_INDICATOR_NOT_USED = 2; // 0x2
+  }
+
+  public final class GnssMeasurementsEvent implements android.os.Parcelable {
+    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
+  }
+
+  public final class GnssNavigationMessageEvent implements android.os.Parcelable {
+    ctor public GnssNavigationMessageEvent(android.location.GnssNavigationMessage);
+    method public int describeContents();
+    method public android.location.GnssNavigationMessage getNavigationMessage();
+    method public void writeToParcel(android.os.Parcel, int);
+    field public static final android.os.Parcelable.Creator<android.location.GnssNavigationMessageEvent> CREATOR;
+    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
+  }
+
+  public static abstract class GnssNavigationMessageEvent.Callback {
+    ctor public GnssNavigationMessageEvent.Callback();
+    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessageEvent);
+    method public void onStatusChanged(int);
+  }
+
+  public abstract interface GnssNmeaListener {
+    method public abstract void onNmeaReceived(long, java.lang.String);
+  }
+
+  public final class GnssStatus {
+    method public int getNumSatellites();
+    method public boolean hasAlmanac(int);
+    method public boolean hasEphemeris(int);
+  }
+
+  public abstract class GnssStatusCallback {
+    ctor public GnssStatusCallback();
+    method public void onFirstFix(int);
+    method public void onSatelliteStatusChanged(android.location.GnssStatus);
+    method public void onStarted();
+    method public void onStopped();
+  }
+
+  public class LocationManager {
+    method public boolean addNmeaListener(android.location.GnssNmeaListener);
+    method public boolean addNmeaListener(android.location.GnssNmeaListener, android.os.Handler);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback, android.os.Handler);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback, android.os.Handler);
+    method public void removeNmeaListener(android.location.GnssNmeaListener);
+    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
+    method public void unregisterGnssStatusCallback(android.location.GnssStatusCallback);
+  }
+
+}
+
 package android.media {
 
   public final class AudioFormat implements android.os.Parcelable {
diff --git a/api/test-current.txt b/api/test-current.txt
index fe7b4d3..fed977a 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -19269,7 +19269,7 @@
     field public static final int ADR_STATE_VALID = 1; // 0x1
     field public static final android.os.Parcelable.Creator<android.location.GnssMeasurement> CREATOR;
     field public static final int MULTIPATH_INDICATOR_DETECTED = 1; // 0x1
-    field public static final int MULTIPATH_INDICATOR_NOT_USED = 2; // 0x2
+    field public static final int MULTIPATH_INDICATOR_NOT_DETECTED = 2; // 0x2
     field public static final int MULTIPATH_INDICATOR_UNKNOWN = 0; // 0x0
     field public static final int STATE_BDS_D2_BIT_SYNC = 256; // 0x100
     field public static final int STATE_BDS_D2_SUBFRAME_SYNC = 512; // 0x200
@@ -19295,15 +19295,15 @@
     method public java.util.Collection<android.location.GnssMeasurement> getMeasurements();
     method public void writeToParcel(android.os.Parcel, int);
     field public static final android.os.Parcelable.Creator<android.location.GnssMeasurementsEvent> CREATOR;
-    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
-    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
-    field public static final int STATUS_READY = 1; // 0x1
   }
 
   public static abstract class GnssMeasurementsEvent.Callback {
     ctor public GnssMeasurementsEvent.Callback();
     method public void onGnssMeasurementsReceived(android.location.GnssMeasurementsEvent);
     method public void onStatusChanged(int);
+    field public static final int STATUS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
   }
 
   public final class GnssNavigationMessage implements android.os.Parcelable {
@@ -19340,36 +19340,24 @@
     field public static final int TYPE_UNKNOWN = 0; // 0x0
   }
 
-  public final class GnssNavigationMessageEvent implements android.os.Parcelable {
-    ctor public GnssNavigationMessageEvent(android.location.GnssNavigationMessage);
-    method public int describeContents();
-    method public android.location.GnssNavigationMessage getNavigationMessage();
-    method public void writeToParcel(android.os.Parcel, int);
-    field public static final android.os.Parcelable.Creator<android.location.GnssNavigationMessageEvent> CREATOR;
-    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+  public static abstract class GnssNavigationMessage.Callback {
+    ctor public GnssNavigationMessage.Callback();
+    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessage);
+    method public void onStatusChanged(int);
+    field public static final int STATUS_LOCATION_DISABLED = 2; // 0x2
     field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
     field public static final int STATUS_READY = 1; // 0x1
   }
 
-  public static abstract class GnssNavigationMessageEvent.Callback {
-    ctor public GnssNavigationMessageEvent.Callback();
-    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessageEvent);
-    method public void onStatusChanged(int);
-  }
-
-  public abstract interface GnssNmeaListener {
-    method public abstract void onNmeaReceived(long, java.lang.String);
-  }
-
   public final class GnssStatus {
     method public float getAzimuthDegrees(int);
     method public float getCn0DbHz(int);
     method public int getConstellationType(int);
     method public float getElevationDegrees(int);
-    method public int getNumSatellites();
+    method public int getSatelliteCount();
     method public int getSvid(int);
-    method public boolean hasAlmanac(int);
-    method public boolean hasEphemeris(int);
+    method public boolean hasAlmanacData(int);
+    method public boolean hasEphemerisData(int);
     method public boolean usedInFix(int);
     field public static final int CONSTELLATION_BEIDOU = 5; // 0x5
     field public static final int CONSTELLATION_GALILEO = 6; // 0x6
@@ -19380,15 +19368,15 @@
     field public static final int CONSTELLATION_UNKNOWN = 0; // 0x0
   }
 
-  public abstract class GnssStatusCallback {
-    ctor public GnssStatusCallback();
+  public static abstract class GnssStatus.Callback {
+    ctor public GnssStatus.Callback();
     method public void onFirstFix(int);
     method public void onSatelliteStatusChanged(android.location.GnssStatus);
     method public void onStarted();
     method public void onStopped();
   }
 
-  public final class GpsSatellite {
+  public final deprecated class GpsSatellite {
     method public float getAzimuth();
     method public float getElevation();
     method public int getPrn();
@@ -19398,7 +19386,7 @@
     method public boolean usedInFix();
   }
 
-  public final class GpsStatus {
+  public final deprecated class GpsStatus {
     method public int getMaxSatellites();
     method public java.lang.Iterable<android.location.GpsSatellite> getSatellites();
     method public int getTimeToFirstFix();
@@ -19408,11 +19396,11 @@
     field public static final int GPS_EVENT_STOPPED = 2; // 0x2
   }
 
-  public static abstract interface GpsStatus.Listener {
+  public static abstract deprecated interface GpsStatus.Listener {
     method public abstract void onGpsStatusChanged(int);
   }
 
-  public static abstract interface GpsStatus.NmeaListener {
+  public static abstract deprecated interface GpsStatus.NmeaListener {
     method public abstract void onNmeaReceived(long, java.lang.String);
   }
 
@@ -19474,8 +19462,8 @@
   public class LocationManager {
     method public deprecated boolean addGpsStatusListener(android.location.GpsStatus.Listener);
     method public deprecated boolean addNmeaListener(android.location.GpsStatus.NmeaListener);
-    method public boolean addNmeaListener(android.location.GnssNmeaListener);
-    method public boolean addNmeaListener(android.location.GnssNmeaListener, android.os.Handler);
+    method public boolean addNmeaListener(android.location.OnNmeaMessageListener);
+    method public boolean addNmeaListener(android.location.OnNmeaMessageListener, android.os.Handler);
     method public void addProximityAlert(double, double, float, long, android.app.PendingIntent);
     method public void addTestProvider(java.lang.String, boolean, boolean, boolean, boolean, boolean, boolean, boolean, int, int);
     method public void clearTestProviderEnabled(java.lang.String);
@@ -19492,13 +19480,13 @@
     method public boolean isProviderEnabled(java.lang.String);
     method public boolean registerGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback);
     method public boolean registerGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback, android.os.Handler);
-    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
-    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback, android.os.Handler);
-    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback);
-    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback, android.os.Handler);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback, android.os.Handler);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatus.Callback);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatus.Callback, android.os.Handler);
     method public deprecated void removeGpsStatusListener(android.location.GpsStatus.Listener);
     method public deprecated void removeNmeaListener(android.location.GpsStatus.NmeaListener);
-    method public void removeNmeaListener(android.location.GnssNmeaListener);
+    method public void removeNmeaListener(android.location.OnNmeaMessageListener);
     method public void removeProximityAlert(android.app.PendingIntent);
     method public void removeTestProvider(java.lang.String);
     method public void removeUpdates(android.location.LocationListener);
@@ -19517,8 +19505,8 @@
     method public void setTestProviderLocation(java.lang.String, android.location.Location);
     method public void setTestProviderStatus(java.lang.String, int, android.os.Bundle, long);
     method public void unregisterGnssMeasurementsCallback(android.location.GnssMeasurementsEvent.Callback);
-    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
-    method public void unregisterGnssStatusCallback(android.location.GnssStatusCallback);
+    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessage.Callback);
+    method public void unregisterGnssStatusCallback(android.location.GnssStatus.Callback);
     field public static final java.lang.String GPS_PROVIDER = "gps";
     field public static final java.lang.String KEY_LOCATION_CHANGED = "location";
     field public static final java.lang.String KEY_PROVIDER_ENABLED = "providerEnabled";
@@ -19547,6 +19535,10 @@
     field public static final int TEMPORARILY_UNAVAILABLE = 1; // 0x1
   }
 
+  public abstract interface OnNmeaMessageListener {
+    method public abstract void onNmeaMessage(java.lang.String, long);
+  }
+
   public abstract class SettingInjectorService extends android.app.Service {
     ctor public SettingInjectorService(java.lang.String);
     method public final android.os.IBinder onBind(android.content.Intent);
diff --git a/api/test-removed.txt b/api/test-removed.txt
index 3f16bca..8c6abdc 100644
--- a/api/test-removed.txt
+++ b/api/test-removed.txt
@@ -84,6 +84,67 @@
 
 }
 
+package android.location {
+
+  public final class GnssMeasurement implements android.os.Parcelable {
+    field public static final int MULTIPATH_INDICATOR_NOT_USED = 2; // 0x2
+  }
+
+  public final class GnssMeasurementsEvent implements android.os.Parcelable {
+    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
+  }
+
+  public final class GnssNavigationMessageEvent implements android.os.Parcelable {
+    ctor public GnssNavigationMessageEvent(android.location.GnssNavigationMessage);
+    method public int describeContents();
+    method public android.location.GnssNavigationMessage getNavigationMessage();
+    method public void writeToParcel(android.os.Parcel, int);
+    field public static final android.os.Parcelable.Creator<android.location.GnssNavigationMessageEvent> CREATOR;
+    field public static final int STATUS_GNSS_LOCATION_DISABLED = 2; // 0x2
+    field public static final int STATUS_NOT_SUPPORTED = 0; // 0x0
+    field public static final int STATUS_READY = 1; // 0x1
+  }
+
+  public static abstract class GnssNavigationMessageEvent.Callback {
+    ctor public GnssNavigationMessageEvent.Callback();
+    method public void onGnssNavigationMessageReceived(android.location.GnssNavigationMessageEvent);
+    method public void onStatusChanged(int);
+  }
+
+  public abstract interface GnssNmeaListener {
+    method public abstract void onNmeaReceived(long, java.lang.String);
+  }
+
+  public final class GnssStatus {
+    method public int getNumSatellites();
+    method public boolean hasAlmanac(int);
+    method public boolean hasEphemeris(int);
+  }
+
+  public abstract class GnssStatusCallback {
+    ctor public GnssStatusCallback();
+    method public void onFirstFix(int);
+    method public void onSatelliteStatusChanged(android.location.GnssStatus);
+    method public void onStarted();
+    method public void onStopped();
+  }
+
+  public class LocationManager {
+    method public boolean addNmeaListener(android.location.GnssNmeaListener);
+    method public boolean addNmeaListener(android.location.GnssNmeaListener, android.os.Handler);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
+    method public boolean registerGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback, android.os.Handler);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback);
+    method public boolean registerGnssStatusCallback(android.location.GnssStatusCallback, android.os.Handler);
+    method public void removeNmeaListener(android.location.GnssNmeaListener);
+    method public void unregisterGnssNavigationMessageCallback(android.location.GnssNavigationMessageEvent.Callback);
+    method public void unregisterGnssStatusCallback(android.location.GnssStatusCallback);
+  }
+
+}
+
 package android.media {
 
   public final class AudioFormat implements android.os.Parcelable {
diff --git a/location/java/android/location/GnssClock.java b/location/java/android/location/GnssClock.java
index df42a73..d1b1be9 100644
--- a/location/java/android/location/GnssClock.java
+++ b/location/java/android/location/GnssClock.java
@@ -22,7 +22,8 @@
 
 /**
  * A class containing a GPS clock timestamp.
- * It represents a measurement of the GPS receiver's clock.
+ *
+ * <p>It represents a measurement of the GPS receiver's clock.
  */
 public final class GnssClock implements Parcelable {
     // The following enumerations must be in sync with the values declared in gps.h
@@ -85,7 +86,7 @@
     }
 
     /**
-     * Returns true if {@link #getLeapSecond()} is available, false otherwise.
+     * Returns {@code true} if {@link #getLeapSecond()} is available, {@code false} otherwise.
      */
     public boolean hasLeapSecond() {
         return isFlagSet(HAS_LEAP_SECOND);
@@ -93,10 +94,12 @@
 
     /**
      * Gets the leap second associated with the clock's time.
-     * The sign of the value is defined by the following equation:
-     *      utc_time_ns = time_ns + (full_bias_ns + bias_ns) - leap_second * 1,000,000,000
      *
-     * The value is only available if {@link #hasLeapSecond()} is true.
+     * <p>The sign of the value is defined by the following equation:
+     * <pre>
+     *     UtcTimeNanos = TimeNanos + (FullBiasNanos + BiasNanos) - LeapSecond * 1,000,000,000</pre>
+     *
+     * <p>The value is only available if {@link #hasLeapSecond()} is {@code true}.
      */
     public int getLeapSecond() {
         return mLeapSecond;
@@ -123,18 +126,15 @@
     }
 
     /**
-     * Gets the GNSS receiver internal clock value in nanoseconds.
+     * Gets the GNSS receiver internal hardware clock value in nanoseconds.
      *
-     * For 'local hardware clock' this value is expected to be monotonically increasing during the
-     * reporting session. The real GPS time can be derived by compensating
-     * {@link #getFullBiasNanos()} (when it is available) from this value.
+     * <p>This value is expected to be monotonically increasing while the hardware clock remains
+     * powered on. For the case of a hardware clock that is not continuously on, see the
+     * {@link #getHardwareClockDiscontinuityCount} field. The GPS time can be derived by adding
+     * {@link #getFullBiasNanos()} and {@link #getBiasNanos()} (when they are available) to this
+     * value. Sub-nanosecond accuracy can be provided by means of {@link #getBiasNanos()}.
      *
-     * For 'GPS time' this value is expected to be the best estimation of current GPS time that GPS
-     * receiver can achieve. {@link #getTimeUncertaintyNanos()} should be available when GPS time is
-     * specified.
-     *
-     * Sub-nanosecond accuracy can be provided by means of {@link #getBiasNanos()}.
-     * The reported time includes {@link #getTimeUncertaintyNanos()}.
+     * <p>The error estimate for this value (if applicable) is {@link #getTimeUncertaintyNanos()}.
      */
     public long getTimeNanos() {
         return mTimeNanos;
@@ -150,7 +150,8 @@
     }
 
     /**
-     * Returns true if {@link #getTimeUncertaintyNanos()} is available, false otherwise.
+     * Returns {@code true} if {@link #getTimeUncertaintyNanos()} is available, {@code false}
+     * otherwise.
      */
     public boolean hasTimeUncertaintyNanos() {
         return isFlagSet(HAS_TIME_UNCERTAINTY);
@@ -158,9 +159,13 @@
 
     /**
      * Gets the clock's time Uncertainty (1-Sigma) in nanoseconds.
-     * The uncertainty is represented as an absolute (single sided) value.
      *
-     * The value is only available if {@link #hasTimeUncertaintyNanos()} is true.
+     * <p>The uncertainty is represented as an absolute (single sided) value.
+     *
+     * <p>The value is only available if {@link #hasTimeUncertaintyNanos()} is {@code true}.
+     *
+     * <p>This value is often effectively zero (it is the reference clock by which all other times
+     * and time uncertainties are measured), and thus this field may often be 0, or not provided.
      */
     public double getTimeUncertaintyNanos() {
         return mTimeUncertaintyNanos;
@@ -187,7 +192,7 @@
     }
 
     /**
-     * Returns true if {@link #getFullBiasNanos()} is available, false otherwise.
+     * Returns {@code true} if {@link #getFullBiasNanos()} is available, {@code false} otherwise.
      */
     public boolean hasFullBiasNanos() {
         return isFlagSet(HAS_FULL_BIAS);
@@ -197,14 +202,18 @@
      * Gets the difference between hardware clock ({@link #getTimeNanos()}) inside GPS receiver and
      * the true GPS time since 0000Z, January 6, 1980, in nanoseconds.
      *
-     * This value is available if the receiver has estimated GPS time. If the computed time is for a
-     * non-GPS constellation, the time offset of that constellation to GPS has to be applied to fill
-     * this value. The value contains the 'bias uncertainty' {@link #getBiasUncertaintyNanos()} in
-     * it, and it should be used for quality check. The value is only available if
-     * {@link #hasFullBiasNanos()} is true.
+     * <p>This value is available if the receiver has estimated GPS time. If the computed time is
+     * for a non-GPS constellation, the time offset of that constellation to GPS has to be applied
+     * to fill this value. The value is only available if {@link #hasFullBiasNanos()} is
+     * {@code true}.
      *
-     * The sign of the value is defined by the following equation:
-     *      local estimate of GPS time = time_ns + (full_bias_ns + bias_ns)
+     * <p>The error estimate for the sum of this field and {@link #getBiasNanos} is
+     * {@link #getBiasUncertaintyNanos()}.
+     *
+     * <p>The sign of the value is defined by the following equation:
+     *
+     * <pre>
+     *     local estimate of GPS time = TimeNanos + (FullBiasNanos + BiasNanos)</pre>
      */
     public long getFullBiasNanos() {
         return mFullBiasNanos;
@@ -231,7 +240,7 @@
     }
 
     /**
-     * Returns true if {@link #getBiasNanos()} is available, false otherwise.
+     * Returns {@code true} if {@link #getBiasNanos()} is available, {@code false} otherwise.
      */
     public boolean hasBiasNanos() {
         return isFlagSet(HAS_BIAS);
@@ -239,9 +248,14 @@
 
     /**
      * Gets the clock's sub-nanosecond bias.
-     * The reported bias includes {@link #getBiasUncertaintyNanos()}.
      *
-     * The value is only available if {@link #hasBiasNanos()} is true.
+     * <p>See the description of how this field is part of converting from hardware clock time, to
+     * GPS time, in {@link #getFullBiasNanos()}.
+     *
+     * <p>The error estimate for the sum of this field and {@link #getFullBiasNanos} is
+     * {@link #getBiasUncertaintyNanos()}.
+     *
+     * <p>The value is only available if {@link #hasBiasNanos()} is {@code true}.
      */
     public double getBiasNanos() {
         return mBiasNanos;
@@ -268,7 +282,8 @@
     }
 
     /**
-     * Returns true if {@link #getBiasUncertaintyNanos()} is available, false otherwise.
+     * Returns {@code true} if {@link #getBiasUncertaintyNanos()} is available, {@code false}
+     * otherwise.
      */
     public boolean hasBiasUncertaintyNanos() {
         return isFlagSet(HAS_BIAS_UNCERTAINTY);
@@ -277,7 +292,10 @@
     /**
      * Gets the clock's Bias Uncertainty (1-Sigma) in nanoseconds.
      *
-     * The value is only available if {@link #hasBiasUncertaintyNanos()} is true.
+     * <p>See the description of how this field provides the error estimate in the conversion from
+     * hardware clock time, to GPS time, in {@link #getFullBiasNanos()}.
+     *
+     * <p>The value is only available if {@link #hasBiasUncertaintyNanos()} is {@code true}.
      */
     public double getBiasUncertaintyNanos() {
         return mBiasUncertaintyNanos;
@@ -304,7 +322,8 @@
     }
 
     /**
-     * Returns true if {@link #getDriftNanosPerSecond()} is available, false otherwise.
+     * Returns {@code true} if {@link #getDriftNanosPerSecond()} is available, {@code false}
+     * otherwise.
      */
     public boolean hasDriftNanosPerSecond() {
         return isFlagSet(HAS_DRIFT);
@@ -312,10 +331,12 @@
 
     /**
      * Gets the clock's Drift in nanoseconds per second.
-     * A positive value indicates that the frequency is higher than the nominal frequency.
-     * The reported drift includes {@link #getDriftUncertaintyNanosPerSecond()}.
      *
-     * The value is only available if {@link #hasDriftNanosPerSecond()} is true.
+     * <p>A positive value indicates that the frequency is higher than the nominal (e.g. GPS master
+     * clock) frequency. The error estimate for this reported drift is
+     * {@link #getDriftUncertaintyNanosPerSecond()}.
+     *
+     * <p>The value is only available if {@link #hasDriftNanosPerSecond()} is {@code true}.
      */
     public double getDriftNanosPerSecond() {
         return mDriftNanosPerSecond;
@@ -342,7 +363,8 @@
     }
 
     /**
-     * Returns true if {@link #getDriftUncertaintyNanosPerSecond()} is available, false otherwise.
+     * Returns {@code true} if {@link #getDriftUncertaintyNanosPerSecond()} is available,
+     * {@code false} otherwise.
      */
     public boolean hasDriftUncertaintyNanosPerSecond() {
         return isFlagSet(HAS_DRIFT_UNCERTAINTY);
@@ -351,7 +373,8 @@
     /**
      * Gets the clock's Drift Uncertainty (1-Sigma) in nanoseconds per second.
      *
-     * The value is only available if {@link #hasDriftUncertaintyNanosPerSecond()} is true.
+     * <p>The value is only available if {@link #hasDriftUncertaintyNanosPerSecond()} is
+     * {@code true}.
      */
     public double getDriftUncertaintyNanosPerSecond() {
         return mDriftUncertaintyNanosPerSecond;
@@ -368,7 +391,29 @@
     }
 
     /**
-     * Gets count of last hardware clock discontinuity.
+     * Resets the clock's Drift Uncertainty (1-Sigma) in nanoseconds per second.
+     * @hide
+     */
+    @TestApi
+    public void resetDriftUncertaintyNanosPerSecond() {
+        resetFlag(HAS_DRIFT_UNCERTAINTY);
+        mDriftUncertaintyNanosPerSecond = Double.NaN;
+    }
+
+    /**
+     * Gets count of hardware clock discontinuities.
+     *
+     * <p>When this value stays the same, vs. a value in a previously reported {@link GnssClock}, it
+     * can be safely assumed that the {@code TimeNanos} value has been derived from a clock that has
+     * been running continuously - e.g. a single continuously powered crystal oscillator, and thus
+     * the {@code (FullBiasNanos + BiasNanos)} offset can be modelled with traditional clock bias
+     * &amp; drift models.
+     *
+     * <p>Each time this value changes, vs. the value in a previously reported {@link GnssClock},
+     * that suggests the hardware clock may have experienced a discontinuity (e.g. a power cycle or
+     * other anomaly), so that any assumptions about modelling a smoothly changing
+     * {@code (FullBiasNanos + BiasNanos)} offset, and a smoothly growing {@code (TimeNanos)}
+     * between this and the previously reported {@code GnssClock}, should be reset.
      */
     public int getHardwareClockDiscontinuityCount() {
         return mHardwareClockDiscontinuityCount;
@@ -383,16 +428,6 @@
         mHardwareClockDiscontinuityCount = value;
     }
 
-    /**
-     * Resets the clock's Drift Uncertainty (1-Sigma) in nanoseconds per second.
-     * @hide
-     */
-    @TestApi
-    public void resetDriftUncertaintyNanosPerSecond() {
-        resetFlag(HAS_DRIFT_UNCERTAINTY);
-        mDriftUncertaintyNanosPerSecond = Double.NaN;
-    }
-
     public static final Creator<GnssClock> CREATOR = new Creator<GnssClock>() {
         @Override
         public GnssClock createFromParcel(Parcel parcel) {
diff --git a/location/java/android/location/GnssMeasurement.java b/location/java/android/location/GnssMeasurement.java
index d78ccee..761ee22 100644
--- a/location/java/android/location/GnssMeasurement.java
+++ b/location/java/android/location/GnssMeasurement.java
@@ -67,18 +67,21 @@
     public @interface MultipathIndicator {}
 
     /**
-     * The indicator is not available or it is unknown.
+     * The indicator is not available or the presence or absence of multipath is unknown.
      */
     public static final int MULTIPATH_INDICATOR_UNKNOWN = 0;
 
     /**
-     * The measurement has been indicated to use multi-path.
+     * The measurement shows signs of multi-path.
      */
     public static final int MULTIPATH_INDICATOR_DETECTED = 1;
 
     /**
-     * The measurement has been indicated not tu use multi-path.
+     * The measurement shows no signs of multi-path.
      */
+    public static final int MULTIPATH_INDICATOR_NOT_DETECTED = 2;
+
+    /** @removed */
     public static final int MULTIPATH_INDICATOR_NOT_USED = 2;
 
     /** This GNSS measurement's tracking state is invalid or unknown. */
@@ -192,15 +195,17 @@
     }
 
     /**
-     * Gets the Pseudo-random number (PRN).
-     * Range: [1, 32]
+     * Gets the satellite ID.
+     *
+     * <p>Interpretation depends on {@link #getConstellationType()}.
+     * See {@link GnssStatus#getSvid(int)}.
      */
     public int getSvid() {
         return mSvid;
     }
 
     /**
-     * Sets the Pseud-random number (PRN).
+     * Sets the Satellite ID.
      * @hide
      */
     @TestApi
@@ -209,7 +214,10 @@
     }
 
     /**
-     * Getst the constellation type.
+     * Gets the constellation type.
+     *
+     * <p>The return value is one of those constants with {@code CONSTELLATION_} prefix in
+     * {@link GnssStatus}.
      */
     @GnssStatus.ConstellationType
     public int getConstellationType() {
@@ -228,13 +236,14 @@
     /**
      * Gets the time offset at which the measurement was taken in nanoseconds.
      *
-     * The reference receiver's time from which this is offset is specified by
+     * <p>The reference receiver's time from which this is offset is specified by
      * {@link GnssClock#getTimeNanos()}.
      *
-     * The sign of this value is given by the following equation:
-     *      measurement time = time_ns + time_offset_ns
+     * <p>The sign of this value is given by the following equation:
+     * <pre>
+     *      measurement time = TimeNanos + TimeOffsetNanos</pre>
      *
-     * The value provides an individual time-stamp for the measurement, and allows sub-nanosecond
+     * <p>The value provides an individual time-stamp for the measurement, and allows sub-nanosecond
      * accuracy.
      */
     public double getTimeOffsetNanos() {
@@ -252,9 +261,10 @@
 
     /**
      * Gets per-satellite sync state.
-     * It represents the current sync state for the associated satellite.
      *
-     * This value helps interpret {@link #getReceivedSvTimeNanos()}.
+     * <p>It represents the current sync state for the associated satellite.
+     *
+     * <p>This value helps interpret {@link #getReceivedSvTimeNanos()}.
      */
     public int getState() {
         return mState;
@@ -271,7 +281,8 @@
 
     /**
      * Gets a string representation of the 'sync state'.
-     * For internal and logging use only.
+     *
+     * <p>For internal and logging use only.
      */
     private String getStateString() {
         if (mState == STATE_UNKNOWN) {
@@ -335,66 +346,79 @@
     /**
      * Gets the received GNSS satellite time, at the measurement time, in nanoseconds.
      *
-     * For GPS &amp; QZSS, this is:
-     *   Received GPS Time-of-Week at the measurement time, in nanoseconds.
-     *   The value is relative to the beginning of the current GPS week.
+     * <p>For GPS &amp; QZSS, this is:
+     * <ul>
+     * <li>Received GPS Time-of-Week at the measurement time, in nanoseconds.</li>
+     * <li>The value is relative to the beginning of the current GPS week.</li>
+     * </ul>
      *
-     *   Given the highest sync state that can be achieved, per each satellite, valid range
-     *   for this field can be:
+     * <p>Given the highest sync state that can be achieved, per each satellite, valid range
+     * for this field can be:
+     * <pre>
      *     Searching       : [ 0       ]   : STATE_UNKNOWN
      *     C/A code lock   : [ 0   1ms ]   : STATE_CODE_LOCK is set
      *     Bit sync        : [ 0  20ms ]   : STATE_BIT_SYNC is set
      *     Subframe sync   : [ 0    6s ]   : STATE_SUBFRAME_SYNC is set
-     *     TOW decoded     : [ 0 1week ]   : STATE_TOW_DECODED is set
+     *     TOW decoded     : [ 0 1week ]   : STATE_TOW_DECODED is set</pre>
      *
-     *   Note well: if there is any ambiguity in integer millisecond,
-     *   STATE_MSEC_AMBIGUOUS should be set accordingly, in the 'state' field.
+     * <p>Note well: if there is any ambiguity in integer millisecond, {@code STATE_MSEC_AMBIGUOUS}
+     * should be set accordingly, in the 'state' field.
      *
-     *   This value must be populated if 'state' != STATE_UNKNOWN.
+     * <p>This value must be populated if 'state' != {@code STATE_UNKNOWN}.
      *
-     * For Glonass, this is:
-     *   Received Glonass time of day, at the measurement time in nanoseconds.
+     * <p>For Glonass, this is:
+     * <ul>
+     * <li>Received Glonass time of day, at the measurement time in nanoseconds.</li>
+     * </ul>
      *
-     *   Given the highest sync state that can be achieved, per each satellite, valid range for
-     *   this field can be:
+     * <p>Given the highest sync state that can be achieved, per each satellite, valid range for
+     * this field can be:
+     * <pre>
      *     Searching       : [ 0       ]   : STATE_UNKNOWN
      *     C/A code lock   : [ 0   1ms ]   : STATE_CODE_LOCK is set
-     *    Symbol sync    : [ 0  10ms ]   : STATE_SYMBOL_SYNC is set
-     *    Bit sync       : [ 0  20ms ]   : STATE_BIT_SYNC is set
-     *     String sync     : [ 0    2s ]   :  STATE_GLO_STRING_SYNC is set
-     *    Time of day      : [ 0  1day ]   : STATE_GLO_TOD_DECODED is set
+     *     Symbol sync     : [ 0  10ms ]   : STATE_SYMBOL_SYNC is set
+     *     Bit sync        : [ 0  20ms ]   : STATE_BIT_SYNC is set
+     *     String sync     : [ 0    2s ]   : STATE_GLO_STRING_SYNC is set
+     *     Time of day     : [ 0  1day ]   : STATE_GLO_TOD_DECODED is set</pre>
      *
-     * For Beidou, this is:
-     *   Received Beidou time of week, at the measurement time in nanoseconds.
+     * <p>For Beidou, this is:
+     * <ul>
+     * <li>Received Beidou time of week, at the measurement time in nanoseconds.</li>
+     * </ul>
      *
-     *   Given the highest sync state that can be achieved, per each satellite, valid range for
-     *   this field can be:
+     * <p>Given the highest sync state that can be achieved, per each satellite, valid range for
+     * this field can be:
+     * <pre>
      *     Searching       : [ 0       ]   : STATE_UNKNOWN
      *     C/A code lock   : [ 0   1ms ]   : STATE_CODE_LOCK is set
      *     Bit sync (D2)   : [ 0   2ms ]   : STATE_BDS_D2_BIT_SYNC is set
      *     Bit sync (D1)   : [ 0  20ms ]   : STATE_BIT_SYNC is set
      *     Subframe (D2)   : [ 0  0.6s ]   : STATE_BDS_D2_SUBFRAME_SYNC is set
      *     Subframe (D1)   : [ 0    6s ]   : STATE_SUBFRAME_SYNC is set
-     *     Time of week    : [ 0 1week ]   : STATE_TOW_DECODED is set
+     *     Time of week    : [ 0 1week ]   : STATE_TOW_DECODED is set</pre>
      *
-     * For Galileo, this is:
-     *   Received Galileo time of week, at the measurement time in nanoseconds.
+     * <p>For Galileo, this is:
+     * <ul>
+     * <li>Received Galileo time of week, at the measurement time in nanoseconds.</li>
+     * </ul>
+     * <pre>
+     *     E1BC code lock   : [ 0   4ms ]  : STATE_GAL_E1BC_CODE_LOCK is set
+     *     E1C 2nd code lock: [ 0 100ms ]  : STATE_GAL_E1C_2ND_CODE_LOCK is set
+     *     E1B page         : [ 0    2s ]  : STATE_GAL_E1B_PAGE_SYNC is set
+     *     Time of week     : [ 0 1week ]  : STATE_GAL_TOW_DECODED is set</pre>
      *
-     *     E1BC code lock  : [ 0   4ms ]   : STATE_GAL_E1BC_CODE_LOCK is set
-     *     E1C 2nd code lock : [ 0   100ms ]   : STATE_GAL_E1C_2ND_CODE_LOCK is set
+     * <p>For SBAS, this is:
+     * <ul>
+     * <li>Received SBAS time, at the measurement time in nanoseconds.</li>
+     * </ul>
      *
-     *     E1B page        : [ 0    2s ]   : STATE_GAL_E1B_PAGE_SYNC is set
-     *     Time of week    : [ 0 1week ]   : STATE_GAL_TOW_DECODED is set
-     *
-     *   For SBAS, this is:
-     *     Received SBAS time, at the measurement time in nanoseconds.
-     *
-     *   Given the highest sync state that can be achieved, per each satellite, valid range for
-     *   this field can be:
+     * <p>Given the highest sync state that can be achieved, per each satellite, valid range for
+     * this field can be:
+     * <pre>
      *     Searching       : [ 0       ]   : STATE_UNKNOWN
      *     C/A code lock   : [ 0   1ms ]   : STATE_CODE_LOCK is set
      *     Symbol sync     : [ 0   2ms ]   : STATE_SYMBOL_SYNC is set
-     *     Message         : [ 0    1s ]   : STATE_SBAS_SYNC is set
+     *     Message         : [ 0    1s ]   : STATE_SBAS_SYNC is set</pre>
      */
     public long getReceivedSvTimeNanos() {
         return mReceivedSvTimeNanos;
@@ -410,7 +434,7 @@
     }
 
     /**
-     * Gets the received GNSS time uncertainty (1-Sigma) in nanoseconds.
+     * Gets the error estimate (1-sigma) for the received GNSS time, in nanoseconds.
      */
     public long getReceivedSvTimeUncertaintyNanos() {
         return mReceivedSvTimeUncertaintyNanos;
@@ -427,9 +451,10 @@
 
     /**
      * Gets the Carrier-to-noise density in dB-Hz.
-     * Range: [0, 63].
      *
-     * The value contains the measured C/N0 for the signal at the antenna input.
+     * <p>Typical range: 10-50 db-Hz.
+     *
+     * <p>The value contains the measured C/N0 for the signal at the antenna input.
      */
     public double getCn0DbHz() {
         return mCn0DbHz;
@@ -447,16 +472,18 @@
     /**
      * Gets the Pseudorange rate at the timestamp in m/s.
      *
-     * The reported value includes {@link #getPseudorangeRateUncertaintyMetersPerSecond()}.
+     * <p>The error estimate for this value is
+     * {@link #getPseudorangeRateUncertaintyMetersPerSecond()}.
      *
-     * The value is uncorrected, hence corrections for receiver and satellite clock frequency errors
-     * should not be included.
+     * <p>The value is uncorrected, i.e. corrections for receiver and satellite clock frequency
+     * errors are not included.
      *
-     * A positive 'uncorrected' value indicates that the SV is moving away from the receiver. The
+     * <p>A positive 'uncorrected' value indicates that the SV is moving away from the receiver. The
      * sign of the 'uncorrected' 'pseudorange rate' and its relation to the sign of 'doppler shift'
      * is given by the equation:
      *
-     *      pseudorange rate = -k * doppler shift   (where k is a constant)
+     * <pre>
+     *      pseudorange rate = -k * doppler shift   (where k is a constant)</pre>
      */
     public double getPseudorangeRateMetersPerSecond() {
         return mPseudorangeRateMetersPerSecond;
@@ -473,7 +500,8 @@
 
     /**
      * Gets the pseudorange's rate uncertainty (1-Sigma) in m/s.
-     * The uncertainty is represented as an absolute (single sided) value.
+     *
+     * <p>The uncertainty is represented as an absolute (single sided) value.
      */
     public double getPseudorangeRateUncertaintyMetersPerSecond() {
         return mPseudorangeRateUncertaintyMetersPerSecond;
@@ -490,7 +518,8 @@
 
     /**
      * Gets 'Accumulated Delta Range' state.
-     * It indicates whether {@link #getAccumulatedDeltaRangeMeters()} is reset or there is a
+     *
+     * <p>It indicates whether {@link #getAccumulatedDeltaRangeMeters()} is reset or there is a
      * cycle slip (indicating 'loss of lock').
      */
     public int getAccumulatedDeltaRangeState() {
@@ -508,7 +537,8 @@
 
     /**
      * Gets a string representation of the 'Accumulated Delta Range state'.
-     * For internal and logging use only.
+     *
+     * <p>For internal and logging use only.
      */
     private String getAccumulatedDeltaRangeStateString() {
         if (mAccumulatedDeltaRangeState == ADR_STATE_UNKNOWN) {
@@ -536,14 +566,17 @@
 
     /**
      * Gets the accumulated delta range since the last channel reset, in meters.
-     * The reported value includes {@link #getAccumulatedDeltaRangeUncertaintyMeters()}.
      *
-     * The availability of the value is represented by {@link #getAccumulatedDeltaRangeState()}.
+     * <p>The error estimate for this value is {@link #getAccumulatedDeltaRangeUncertaintyMeters()}.
      *
-     * A positive value indicates that the SV is moving away from the receiver.
+     * <p>The availability of the value is represented by {@link #getAccumulatedDeltaRangeState()}.
+     *
+     * <p>A positive value indicates that the SV is moving away from the receiver.
      * The sign of {@link #getAccumulatedDeltaRangeMeters()} and its relation to the sign of
      * {@link #getCarrierPhase()} is given by the equation:
-     *          accumulated delta range = -k * carrier phase    (where k is a constant)
+     *
+     * <pre>
+     *          accumulated delta range = -k * carrier phase    (where k is a constant)</pre>
      */
     public double getAccumulatedDeltaRangeMeters() {
         return mAccumulatedDeltaRangeMeters;
@@ -560,9 +593,10 @@
 
     /**
      * Gets the accumulated delta range's uncertainty (1-Sigma) in meters.
-     * The uncertainty is represented as an absolute (single sided) value.
      *
-     * The status of the value is represented by {@link #getAccumulatedDeltaRangeState()}.
+     * <p>The uncertainty is represented as an absolute (single sided) value.
+     *
+     * <p>The status of the value is represented by {@link #getAccumulatedDeltaRangeState()}.
      */
     public double getAccumulatedDeltaRangeUncertaintyMeters() {
         return mAccumulatedDeltaRangeUncertaintyMeters;
@@ -571,7 +605,7 @@
     /**
      * Sets the accumulated delta range's uncertainty (1-sigma) in meters.
      *
-     * The status of the value is represented by {@link #getAccumulatedDeltaRangeState()}.
+     * <p>The status of the value is represented by {@link #getAccumulatedDeltaRangeState()}.
      *
      * @hide
      */
@@ -581,17 +615,20 @@
     }
 
     /**
-     * Returns true if {@link #getCarrierFrequencyHz()} is available, false otherwise.
+     * Returns {@code true} if {@link #getCarrierFrequencyHz()} is available, {@code false}
+     * otherwise.
      */
     public boolean hasCarrierFrequencyHz() {
         return isFlagSet(HAS_CARRIER_FREQUENCY);
     }
 
     /**
-     * Gets the carrier frequency at which codes and messages are modulated, it can be L1 or L2.
-     * If the field is not set, the carrier frequency corresponds to L1.
+     * Gets the carrier frequency at which codes and messages are modulated.
      *
-     * The value is only available if {@link #hasCarrierFrequencyHz()} is true.
+     * <p>For GPS, e.g., it can be L1 or L2.  If the field is not set, it is the primary common use
+     * frequency, e.g. L1 for GPS.
+     *
+     * <p>The value is only available if {@link #hasCarrierFrequencyHz()} is {@code true}.
      */
     public float getCarrierFrequencyHz() {
         return mCarrierFrequencyHz;
@@ -618,7 +655,7 @@
     }
 
     /**
-     * Returns true if {@link #getCarrierCycles()} is available, false otherwise.
+     * Returns {@code true} if {@link #getCarrierCycles()} is available, {@code false} otherwise.
      */
     public boolean hasCarrierCycles() {
         return isFlagSet(HAS_CARRIER_CYCLES);
@@ -626,9 +663,10 @@
 
     /**
      * The number of full carrier cycles between the satellite and the receiver.
-     * The reference frequency is given by the value of {@link #getCarrierFrequencyHz()}.
      *
-     * The value is only available if {@link #hasCarrierCycles()} is true.
+     * <p>The reference frequency is given by the value of {@link #getCarrierFrequencyHz()}.
+     *
+     * <p>The value is only available if {@link #hasCarrierCycles()} is {@code true}.
      */
     public long getCarrierCycles() {
         return mCarrierCycles;
@@ -655,7 +693,7 @@
     }
 
     /**
-     * Returns true if {@link #getCarrierPhase()} is available, false otherwise.
+     * Returns {@code true} if {@link #getCarrierPhase()} is available, {@code false} otherwise.
      */
     public boolean hasCarrierPhase() {
         return isFlagSet(HAS_CARRIER_PHASE);
@@ -663,13 +701,16 @@
 
     /**
      * Gets the RF phase detected by the receiver.
-     * Range: [0.0, 1.0].
-     * This is usually the fractional part of the complete carrier phase measurement.
      *
-     * The reference frequency is given by the value of {@link #getCarrierFrequencyHz()}.
-     * The reported carrier-phase includes {@link #getCarrierPhaseUncertainty()}.
+     * <p>Range: [0.0, 1.0].
      *
-     * The value is only available if {@link #hasCarrierPhase()} is true.
+     * <p>This is the fractional part of the complete carrier phase measurement.
+     *
+     * <p>The reference frequency is given by the value of {@link #getCarrierFrequencyHz()}.
+     *
+     * <p>The error estimate for this value is {@link #getCarrierPhaseUncertainty()}.
+     *
+     * <p>The value is only available if {@link #hasCarrierPhase()} is {@code true}.
      */
     public double getCarrierPhase() {
         return mCarrierPhase;
@@ -696,7 +737,8 @@
     }
 
     /**
-     * Returns true if {@link #getCarrierPhaseUncertainty()} is available, false otherwise.
+     * Returns {@code true} if {@link #getCarrierPhaseUncertainty()} is available, {@code false}
+     * otherwise.
      */
     public boolean hasCarrierPhaseUncertainty() {
         return isFlagSet(HAS_CARRIER_PHASE_UNCERTAINTY);
@@ -704,9 +746,10 @@
 
     /**
      * Gets the carrier-phase's uncertainty (1-Sigma).
-     * The uncertainty is represented as an absolute (single sided) value.
      *
-     * The value is only available if {@link #hasCarrierPhaseUncertainty()} is true.
+     * <p>The uncertainty is represented as an absolute (single sided) value.
+     *
+     * <p>The value is only available if {@link #hasCarrierPhaseUncertainty()} is {@code true}.
      */
     public double getCarrierPhaseUncertainty() {
         return mCarrierPhaseUncertainty;
@@ -751,7 +794,8 @@
 
     /**
      * Gets a string representation of the 'multi-path indicator'.
-     * For internal and logging use only.
+     *
+     * <p>For internal and logging use only.
      */
     private String getMultipathIndicatorString() {
         switch(mMultipathIndicator) {
@@ -767,7 +811,7 @@
     }
 
     /**
-     * Returns true if {@link #getSnrInDb()} is available, false otherwise.
+     * Returns {@code true} if {@link #getSnrInDb()} is available, {@code false} otherwise.
      */
     public boolean hasSnrInDb() {
         return isFlagSet(HAS_SNR);
@@ -776,7 +820,7 @@
     /**
      * Gets the Signal-to-Noise ratio (SNR) in dB.
      *
-     * The value is only available if {@link #hasSnrInDb()} is true.
+     * <p>The value is only available if {@link #hasSnrInDb()} is {@code true}.
      */
     public double getSnrInDb() {
         return mSnrInDb;
diff --git a/location/java/android/location/GnssMeasurementsEvent.java b/location/java/android/location/GnssMeasurementsEvent.java
index ec252a8..3151694 100644
--- a/location/java/android/location/GnssMeasurementsEvent.java
+++ b/location/java/android/location/GnssMeasurementsEvent.java
@@ -16,6 +16,7 @@
 
 package android.location;
 
+import android.annotation.TestApi;
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.os.Parcel;
@@ -33,29 +34,11 @@
  * Events are delivered to registered instances of {@link Callback}.
  */
 public final class GnssMeasurementsEvent implements Parcelable {
-    /**
-     * The status of the GNSS measurements event.
-     * @hide
-     */
-    @Retention(RetentionPolicy.SOURCE)
-    @IntDef({STATUS_NOT_SUPPORTED, STATUS_READY, STATUS_GNSS_LOCATION_DISABLED})
-    public @interface GnssMeasurementsStatus {}
-
-    /**
-     * The system does not support tracking of GNSS Measurements. This status will not change in the
-     * future.
-     */
+    /** @removed */
     public static final int STATUS_NOT_SUPPORTED = 0;
-
-    /**
-     * GNSS Measurements are successfully being tracked, it will receive updates once they are
-     * available.
-     */
+    /** @removed */
     public static final int STATUS_READY = 1;
-
-    /**
-     * GNSS provider or Location is disabled, updates will not be received until they are enabled.
-     */
+    /** @removed */
     public static final int STATUS_GNSS_LOCATION_DISABLED = 2;
 
     private final GnssClock mClock;
@@ -68,6 +51,32 @@
      * {@link LocationManager#registerGnssMeasurementsCallback}.
      */
     public static abstract class Callback {
+        /**
+         * The status of the GNSS measurements event.
+         * @hide
+         */
+        @Retention(RetentionPolicy.SOURCE)
+        @IntDef({STATUS_NOT_SUPPORTED, STATUS_READY, STATUS_LOCATION_DISABLED})
+        public @interface GnssMeasurementsStatus {}
+
+        /**
+         * The system does not support tracking of GNSS Measurements.
+         *
+         * <p>This status will not change in the future.
+         */
+        public static final int STATUS_NOT_SUPPORTED = 0;
+
+        /**
+         * GNSS Measurements are successfully being tracked, it will receive updates once they are
+         * available.
+         */
+        public static final int STATUS_READY = 1;
+
+        /**
+         * GPS provider or Location is disabled, updates will not be received until they are
+         * enabled.
+         */
+        public static final int STATUS_LOCATION_DISABLED = 2;
 
         /**
          * Reports the latest collected GNSS Measurements.
@@ -80,6 +89,10 @@
         public void onStatusChanged(@GnssMeasurementsStatus int status) {}
     }
 
+    /**
+     * @hide
+     */
+    @TestApi
     public GnssMeasurementsEvent(GnssClock clock, GnssMeasurement[] measurements) {
         if (clock == null) {
             throw new InvalidParameterException("Parameter 'clock' must not be null.");
@@ -94,6 +107,10 @@
         mReadOnlyMeasurements = Collections.unmodifiableCollection(measurementCollection);
     }
 
+    /**
+     * Gets the GNSS receiver clock information associated with the measurements for the current
+     * event.
+     */
     @NonNull
     public GnssClock getClock() {
         return mClock;
diff --git a/location/java/android/location/GnssNavigationMessage.aidl b/location/java/android/location/GnssNavigationMessage.aidl
new file mode 100644
index 0000000..1cdd510
--- /dev/null
+++ b/location/java/android/location/GnssNavigationMessage.aidl
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2016, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.location;
+
+parcelable GnssNavigationMessage;
diff --git a/location/java/android/location/GnssNavigationMessage.java b/location/java/android/location/GnssNavigationMessage.java
index a5eace8..aa26111 100644
--- a/location/java/android/location/GnssNavigationMessage.java
+++ b/location/java/android/location/GnssNavigationMessage.java
@@ -34,7 +34,7 @@
     private static final byte[] EMPTY_ARRAY = new byte[0];
 
     /**
-     * The type of the GPS Clock.
+     * The type of the GNSS Navigation Message
      * @hide
      */
     @Retention(RetentionPolicy.SOURCE)
@@ -81,6 +81,51 @@
      */
     public static final int STATUS_PARITY_REBUILT = (1<<1);
 
+    /**
+     * Used for receiving GNSS satellite Navigation Messages from the GNSS engine.
+     *
+     * <p>You can implement this interface and call
+     * {@link LocationManager#registerGnssNavigationMessageCallback}.
+     */
+    public static abstract class Callback {
+        /**
+         * The status of GNSS measurements event.
+         * @hide
+         */
+        @Retention(RetentionPolicy.SOURCE)
+        @IntDef({STATUS_NOT_SUPPORTED, STATUS_READY, STATUS_LOCATION_DISABLED})
+        public @interface GnssNavigationMessageStatus {}
+
+        /**
+         * The system does not support tracking of GNSS Navigation Messages.
+         *
+         * This status will not change in the future.
+         */
+        public static final int STATUS_NOT_SUPPORTED = 0;
+
+        /**
+         * GNSS Navigation Messages are successfully being tracked, it will receive updates once
+         * they are available.
+         */
+        public static final int STATUS_READY = 1;
+
+        /**
+         * GNSS provider or Location is disabled, updated will not be received until they are
+         * enabled.
+         */
+        public static final int STATUS_LOCATION_DISABLED = 2;
+
+        /**
+         * Returns the latest collected GNSS Navigation Message.
+         */
+        public void onGnssNavigationMessageReceived(GnssNavigationMessage event) {}
+
+        /**
+         * Returns the latest status of the GNSS Navigation Messages sub-system.
+         */
+        public void onStatusChanged(@GnssNavigationMessageStatus int status) {}
+    }
+
     // End enumerations in sync with gps.h
 
     private int mType;
@@ -170,15 +215,16 @@
     }
 
     /**
-     * Gets the Pseudo-random number.
-     * Range: [1, 32].
+     * Gets the satellite ID.
+     *
+     * <p>Range varies by constellation.  See definition at {@code GnssStatus#getSvid(int)}
      */
     public int getSvid() {
         return mSvid;
     }
 
     /**
-     * Sets the Pseud-random number.
+     * Sets the satellite ID.
      * @hide
      */
     @TestApi
@@ -187,10 +233,25 @@
     }
 
     /**
-     * Gets the Message Identifier.
-     * It provides an index so the complete Navigation Message can be assembled. i.e. for L1 C/A
-     * subframe 4 and 5, this value corresponds to the 'frame id' of the navigation message.
-     * Subframe 1, 2, 3 does not contain a 'frame id' and this might be reported as -1.
+     * Gets the Message identifier.
+     *
+     * <p>This provides an index to help with complete Navigation Message assembly. Similar
+     * identifiers within the data bits themselves often supplement this information, in ways even
+     * more specific to each message type; see the relevant satellite constellation ICDs for
+     * details.
+     *
+     * <ul>
+     * <li> For GPS L1 C/A subframe 4 and 5, this value corresponds to the 'frame id' of the
+     * navigation message, in the range of 1-25 (Subframe 1, 2, 3 does not contain a 'frame id' and
+     * this value can be set to -1.)</li>
+     * <li> For Glonass L1 C/A, this refers to the frame ID, in the range of 1-5.</li>
+     * <li> For BeiDou D1, this refers to the frame number in the range of 1-24</li>
+     * <li> For Beidou D2, this refers to the frame number, in the range of 1-120</li>
+     * <li> For Galileo F/NAV nominal frame structure, this refers to the subframe number, in the
+     * range of 1-12</li>
+     * <li> For Galileo I/NAV nominal frame structure, this refers to the subframe number in the
+     * range of 1-24</li>
+     * </ul>
      */
     public int getMessageId() {
         return mMessageId;
@@ -206,10 +267,18 @@
     }
 
     /**
-     * Gets the Sub-message Identifier.
-     * If required by {@link #getType()}, this value contains a sub-index within the current message
-     * (or frame) that is being transmitted. i.e. for L1 C/A the sub-message identifier corresponds
-     * to the sub-frame Id of the navigation message.
+     * Gets the sub-message identifier, relevant to the {@link #getType()} of the message.
+     *
+     * <ul>
+     * <li> For GPS L1 C/A, BeiDou D1 &amp; BeiDou D2, the submessage id corresponds to the subframe
+     * number of the navigation message, in the range of 1-5.</li>
+     * <li>For Glonass L1 C/A, this refers to the String number, in the range from 1-15</li>
+     * <li>For Galileo F/NAV, this refers to the page type in the range 1-6</li>
+     * <li>For Galileo I/NAV, this refers to the word type in the range 1-10+</li>
+     * <li>For Galileo in particular, the type information embedded within the data bits may be even
+     * more useful in interpretation, than the nominal page and word types provided in this
+     * field.</li>
+     * </ul>
      */
     public int getSubmessageId() {
         return mSubmessageId;
@@ -225,8 +294,25 @@
     }
 
     /**
-     * Gets the data associated with the Navigation Message.
-     * The bytes (or words) specified using big endian format (MSB first).
+     * Gets the data of the reported GPS message.
+     *
+     * <p>The bytes (or words) specified using big endian format (MSB first).
+     *
+     * <ul>
+     * <li>For GPS L1 C/A, Beidou D1 &amp; Beidou D2, each subframe contains 10 30-bit words. Each
+     * word (30 bits) should be fit into the last 30 bits in a 4-byte word (skip B31 and B32), with
+     * MSB first, for a total of 40 bytes, covering a time period of 6, 6, and 0.6 seconds,
+     * respectively.</li>
+     * <li>For Glonass L1 C/A, each string contains 85 data bits, including the checksum.  These
+     * bits should be fit into 11 bytes, with MSB first (skip B86-B88), covering a time period of 2
+     * seconds.</li>
+     * <li>For Galileo F/NAV, each word consists of 238-bit (sync &amp; tail symbols excluded). Each
+     * word should be fit into 30-bytes, with MSB first (skip B239, B240), covering a time period of
+     * 10 seconds.</li>
+     * <li>For Galileo I/NAV, each page contains 2 page parts, even and odd, with a total of 2x114 =
+     * 228 bits, (sync &amp; tail excluded) that should be fit into 29 bytes, with MSB first (skip
+     * B229-B232).</li>
+     * </ul>
      */
     @NonNull
     public byte[] getData() {
diff --git a/location/java/android/location/GnssNavigationMessageCallbackTransport.java b/location/java/android/location/GnssNavigationMessageCallbackTransport.java
index 4204b99..1eafd02 100644
--- a/location/java/android/location/GnssNavigationMessageCallbackTransport.java
+++ b/location/java/android/location/GnssNavigationMessageCallbackTransport.java
@@ -20,12 +20,12 @@
 import android.os.RemoteException;
 
 /**
- * A handler class to manage transport callback for {@link GnssNavigationMessageEvent.Callback}.
+ * A handler class to manage transport callback for {@link GnssNavigationMessage.Callback}.
  *
  * @hide
  */
 class GnssNavigationMessageCallbackTransport
-        extends LocalListenerHelper<GnssNavigationMessageEvent.Callback> {
+        extends LocalListenerHelper<GnssNavigationMessage.Callback> {
     private final ILocationManager mLocationManager;
 
     private final IGnssNavigationMessageListener mListenerTransport = new ListenerTransport();
@@ -51,11 +51,11 @@
 
     private class ListenerTransport extends IGnssNavigationMessageListener.Stub {
         @Override
-        public void onGnssNavigationMessageReceived(final GnssNavigationMessageEvent event) {
-            ListenerOperation<GnssNavigationMessageEvent.Callback> operation =
-                    new ListenerOperation<GnssNavigationMessageEvent.Callback>() {
+        public void onGnssNavigationMessageReceived(final GnssNavigationMessage event) {
+            ListenerOperation<GnssNavigationMessage.Callback> operation =
+                    new ListenerOperation<GnssNavigationMessage.Callback>() {
                 @Override
-                public void execute(GnssNavigationMessageEvent.Callback callback)
+                public void execute(GnssNavigationMessage.Callback callback)
                         throws RemoteException {
                     callback.onGnssNavigationMessageReceived(event);
                 }
@@ -65,10 +65,10 @@
 
         @Override
         public void onStatusChanged(final int status) {
-            ListenerOperation<GnssNavigationMessageEvent.Callback> operation =
-                    new ListenerOperation<GnssNavigationMessageEvent.Callback>() {
+            ListenerOperation<GnssNavigationMessage.Callback> operation =
+                    new ListenerOperation<GnssNavigationMessage.Callback>() {
                 @Override
-                public void execute(GnssNavigationMessageEvent.Callback callback)
+                public void execute(GnssNavigationMessage.Callback callback)
                         throws RemoteException {
                     callback.onStatusChanged(status);
                 }
diff --git a/location/java/android/location/GnssNavigationMessageEvent.java b/location/java/android/location/GnssNavigationMessageEvent.java
index 992dfc3..f7e5665 100644
--- a/location/java/android/location/GnssNavigationMessageEvent.java
+++ b/location/java/android/location/GnssNavigationMessageEvent.java
@@ -28,10 +28,11 @@
 /**
  * A class implementing a container for data associated with a navigation message event.
  * Events are delivered to registered instances of {@link Callback}.
+ * @removed
  */
 public final class GnssNavigationMessageEvent implements Parcelable {
     /**
-     * The status of GPS measurements event.
+     * The status of GNSS measurements event.
      * @hide
      */
     @Retention(RetentionPolicy.SOURCE)
@@ -39,38 +40,40 @@
     public @interface GnssNavigationMessageStatus {}
 
     /**
-     * The system does not support tracking of GPS Navigation Messages. This status will not change
-     * in the future.
+     * The system does not support tracking of GNSS Navigation Messages.
+     *
+     * This status will not change in the future.
      */
     public static final int STATUS_NOT_SUPPORTED = 0;
 
     /**
-     * GPS Navigation Messages are successfully being tracked, it will receive updates once they are
-     * available.
+     * GNSS Navigation Messages are successfully being tracked, it will receive updates once they
+     * are available.
      */
     public static final int STATUS_READY = 1;
 
     /**
-     * GPS provider or Location is disabled, updated will not be received until they are enabled.
+     * GNSS provider or Location is disabled, updated will not be received until they are enabled.
      */
     public static final int STATUS_GNSS_LOCATION_DISABLED = 2;
 
     private final GnssNavigationMessage mNavigationMessage;
 
     /**
-     * Used for receiving GPS satellite Navigation Messages from the GPS engine.
-     * You can implement this interface and call
+     * Used for receiving GNSS satellite Navigation Messages from the GNSS engine.
+     *
+     * <p>You can implement this interface and call
      * {@link LocationManager#registerGnssNavigationMessageCallback}.
      */
     public static abstract class Callback {
 
         /**
-         * Returns the latest collected GPS Navigation Message.
+         * Returns the latest collected GNSS Navigation Message.
          */
         public void onGnssNavigationMessageReceived(GnssNavigationMessageEvent event) {}
 
         /**
-         * Returns the latest status of the GPS Navigation Messages sub-system.
+         * Returns the latest status of the GNSS Navigation Messages sub-system.
          */
         public void onStatusChanged(@GnssNavigationMessageStatus int status) {}
     }
diff --git a/location/java/android/location/GnssNmeaListener.java b/location/java/android/location/GnssNmeaListener.java
index 6c9b08a..756ae49 100644
--- a/location/java/android/location/GnssNmeaListener.java
+++ b/location/java/android/location/GnssNmeaListener.java
@@ -23,8 +23,9 @@
 * See <a href="http://en.wikipedia.org/wiki/NMEA_0183">NMEA 0183</a> for more details.
 * You can implement this interface and call {@link LocationManager#addNmeaListener}
 * to receive NMEA data from the GNSS engine.
+* @removed
 */
 public interface GnssNmeaListener {
     /** Called when an NMEA message is received. */
     void onNmeaReceived(long timestamp, String nmea);
-}
\ No newline at end of file
+}
diff --git a/location/java/android/location/GnssStatus.java b/location/java/android/location/GnssStatus.java
index d76feec..e834c30 100644
--- a/location/java/android/location/GnssStatus.java
+++ b/location/java/android/location/GnssStatus.java
@@ -23,9 +23,11 @@
 
 /**
  * This class represents the current state of the GNSS engine.
- * This class is used in conjunction with the {@link GnssStatusCallback}.
+ * This class is used in conjunction with the {@link GnssStatus.Callback}.
  */
 public final class GnssStatus {
+    // these must match the definitions in gps.h
+
     /** Unknown constellation type. */
     public static final int CONSTELLATION_UNKNOWN = 0;
     /** Constellation type constant for GPS. */
@@ -41,16 +43,6 @@
     /** Constellation type constant for Galileo. */
     public static final int CONSTELLATION_GALILEO = 6;
 
-    /**
-     * Constellation type.
-     * @hide
-     */
-    @Retention(RetentionPolicy.SOURCE)
-    @IntDef({CONSTELLATION_UNKNOWN, CONSTELLATION_GPS, CONSTELLATION_SBAS, CONSTELLATION_GLONASS,
-            CONSTELLATION_QZSS, CONSTELLATION_BEIDOU, CONSTELLATION_GALILEO})
-    public @interface ConstellationType {}
-
-    // these must match the definitions in gps.h
     /** @hide */
     public static final int GNSS_SV_FLAGS_NONE = 0;
     /** @hide */
@@ -67,6 +59,42 @@
     /** @hide */
     public static final int CONSTELLATION_TYPE_MASK = 0xf;
 
+    /**
+     * Used for receiving notifications when GNSS events happen.
+     */
+    public static abstract class Callback {
+        /**
+         * Called when GNSS system has started.
+         */
+        public void onStarted() {}
+
+        /**
+         * Called when GNSS system has stopped.
+         */
+        public void onStopped() {}
+
+        /**
+         * Called when the GNSS system has received its first fix since starting.
+         * @param ttffMillis the time from start to first fix in milliseconds.
+         */
+        public void onFirstFix(int ttffMillis) {}
+
+        /**
+         * Called periodically to report GNSS satellite status.
+         * @param status the current status of all satellites.
+         */
+        public void onSatelliteStatusChanged(GnssStatus status) {}
+    }
+
+    /**
+     * Constellation type.
+     * @hide
+     */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({CONSTELLATION_UNKNOWN, CONSTELLATION_GPS, CONSTELLATION_SBAS, CONSTELLATION_GLONASS,
+            CONSTELLATION_QZSS, CONSTELLATION_BEIDOU, CONSTELLATION_GALILEO})
+    public @interface ConstellationType {}
+
     /* These package private values are modified by the LocationManager class */
     /* package */ int[] mSvidWithFlags;
     /* package */ float[] mCn0DbHz;
@@ -83,15 +111,21 @@
         mAzimuths = azimuths;
     }
 
+    /** @removed */
+    public int getNumSatellites() {
+        return getSatelliteCount();
+    }
+
     /**
      * Gets the total number of satellites in satellite list.
      */
-    public int getNumSatellites() {
+    public int getSatelliteCount() {
         return mSvCount;
     }
 
     /**
-     * Retrieves the constellation type of the satellite at the specified position.
+     * Retrieves the constellation type of the satellite at the specified index.
+     *
      * @param satIndex the index of the satellite in the list.
      */
     @ConstellationType
@@ -101,7 +135,30 @@
     }
 
     /**
-     * Retrieves the pseudo-random number of the satellite at the specified position.
+     * Gets the identification number for the satellite at the specific index.
+     *
+     * <p>This svid is pseudo-random number for most constellations. It is FCN &amp; OSN number for
+     * Glonass.
+     *
+     * <p>The distinction is made by looking at constellation field
+     * {@link #getConstellationType(int)} Expected values are in the range of:
+     *
+     * <ul>
+     * <li>GPS: 1-32</li>
+     * <li>SBAS: 120-151, 183-192</li>
+     * <li>GLONASS:
+     * <ul>
+     *   <li>The least significant 8 bits, signed, are the orbital slot number (OSN) in the range
+     *   from 1-24, if known, or -127 if unknown</li>
+     *   <li>The next least signficant 8 bits, signed, are the frequency channel number (FCN) in the
+     *   range from -7 to +6, if known, and -127, if unknown</li>
+     *   <li>At least one of the two (FCN &amp; OSN) shall be set to a known value</li>
+     * </ul></li>
+     * <li>QZSS: 193-200</li>
+     * <li>Galileo: 1-36</li>
+     * <li>Beidou: 1-37</li>
+     * </ul>
+     *
      * @param satIndex the index of the satellite in the list.
      */
     public int getSvid(int satIndex) {
@@ -109,7 +166,9 @@
     }
 
     /**
-     * Retrieves the signal-noise ration of the satellite at the specified position.
+     * Retrieves the carrier-to-noise density at the antenna of the satellite at the specified index
+     * in dB-Hz.
+     *
      * @param satIndex the index of the satellite in the list.
      */
     public float getCn0DbHz(int satIndex) {
@@ -117,7 +176,8 @@
     }
 
     /**
-     * Retrieves the elevation of the satellite at the specified position.
+     * Retrieves the elevation of the satellite at the specified index.
+     *
      * @param satIndex the index of the satellite in the list.
      */
     public float getElevationDegrees(int satIndex) {
@@ -125,31 +185,46 @@
     }
 
     /**
-     * Retrieves the azimuth the satellite at the specified position.
+     * Retrieves the azimuth the satellite at the specified index.
+     *
      * @param satIndex the index of the satellite in the list.
      */
     public float getAzimuthDegrees(int satIndex) {
         return mAzimuths[satIndex];
     }
 
-    /**
-     * Detects whether the satellite at the specified position has ephemeris data.
-     * @param satIndex the index of the satellite in the list.
-     */
+    /** @removed */
     public boolean hasEphemeris(int satIndex) {
-        return (mSvidWithFlags[satIndex] & GNSS_SV_FLAGS_HAS_EPHEMERIS_DATA) != 0;
+        return hasEphemerisData(satIndex);
     }
 
     /**
-     * Detects whether the satellite at the specified position has almanac data.
+     * Reports whether the satellite at the specified index has ephemeris data.
+     *
      * @param satIndex the index of the satellite in the list.
      */
+    public boolean hasEphemerisData(int satIndex) {
+        return (mSvidWithFlags[satIndex] & GNSS_SV_FLAGS_HAS_EPHEMERIS_DATA) != 0;
+    }
+
+    /** @removed */
     public boolean hasAlmanac(int satIndex) {
+        return hasAlmanacData(satIndex);
+    }
+
+    /**
+     * Reports whether the satellite at the specified index has almanac data.
+     *
+     * @param satIndex the index of the satellite in the list.
+     */
+    public boolean hasAlmanacData(int satIndex) {
         return (mSvidWithFlags[satIndex] & GNSS_SV_FLAGS_HAS_ALMANAC_DATA) != 0;
     }
 
     /**
-     * Detects whether the satellite at the specified position is used in fix.
+     * Reports whether the satellite at the specified index was used in the calculation of the most
+     * recent position fix.
+     *
      * @param satIndex the index of the satellite in the list.
      */
     public boolean usedInFix(int satIndex) {
diff --git a/location/java/android/location/GnssStatusCallback.java b/location/java/android/location/GnssStatusCallback.java
index 0d2955a..bf295ef 100644
--- a/location/java/android/location/GnssStatusCallback.java
+++ b/location/java/android/location/GnssStatusCallback.java
@@ -18,6 +18,7 @@
 
 /**
  * Used for receiving notifications when GNSS events happen.
+ * @removed
  */
 public abstract class GnssStatusCallback {
     /**
diff --git a/location/java/android/location/GpsSatellite.java b/location/java/android/location/GpsSatellite.java
index 820f5746..788d01e 100644
--- a/location/java/android/location/GpsSatellite.java
+++ b/location/java/android/location/GpsSatellite.java
@@ -18,8 +18,12 @@
 
 /**
  * This class represents the current state of a GPS satellite.
+ *
  * This class is used in conjunction with the {@link GpsStatus} class.
+ *
+ * @deprecated use {@link GnssStatus} and {@link GnssStatus.Callback}.
  */
+@Deprecated
 public final class GpsSatellite {
     /* These package private values are modified by the GpsStatus class */
     boolean mValid;
diff --git a/location/java/android/location/GpsStatus.java b/location/java/android/location/GpsStatus.java
index bc518f9..038247b 100644
--- a/location/java/android/location/GpsStatus.java
+++ b/location/java/android/location/GpsStatus.java
@@ -24,8 +24,12 @@
 
 /**
  * This class represents the current state of the GPS engine.
- * This class is used in conjunction with the {@link Listener} interface.
+ *
+ * <p>This class is used in conjunction with the {@link Listener} interface.
+ *
+ * @deprecated use {@link GnssStatus} and {@link GnssStatus.Callback}.
  */
+@Deprecated
 public final class GpsStatus {
     private static final int NUM_SATELLITES = 255;
 
@@ -102,7 +106,9 @@
 
     /**
      * Used for receiving notifications when GPS status has changed.
+     * @deprecated use {@link GnssStatus.Callback} instead.
      */
+    @Deprecated
     public interface Listener {
         /**
          * Called to report changes in the GPS status.
@@ -130,7 +136,9 @@
      * See <a href="http://en.wikipedia.org/wiki/NMEA_0183">NMEA 0183</a> for more details.
      * You can implement this interface and call {@link LocationManager#addNmeaListener}
      * to receive NMEA data from the GPS engine.
+     * @deprecated use {@link OnNmeaMessageListener} instead.
      */
+    @Deprecated
     public interface NmeaListener {
         void onNmeaReceived(long timestamp, String nmea);
     }
diff --git a/location/java/android/location/IGnssNavigationMessageListener.aidl b/location/java/android/location/IGnssNavigationMessageListener.aidl
index de6129c..3e49b5b 100644
--- a/location/java/android/location/IGnssNavigationMessageListener.aidl
+++ b/location/java/android/location/IGnssNavigationMessageListener.aidl
@@ -16,12 +16,12 @@
 
 package android.location;
 
-import android.location.GnssNavigationMessageEvent;
+import android.location.GnssNavigationMessage;
 
 /**
  * {@hide}
  */
 oneway interface IGnssNavigationMessageListener {
-    void onGnssNavigationMessageReceived(in GnssNavigationMessageEvent event);
+    void onGnssNavigationMessageReceived(in GnssNavigationMessage event);
     void onStatusChanged(in int status);
 }
diff --git a/location/java/android/location/LocationManager.java b/location/java/android/location/LocationManager.java
index 28db099..b246360 100644
--- a/location/java/android/location/LocationManager.java
+++ b/location/java/android/location/LocationManager.java
@@ -70,10 +70,16 @@
             new HashMap<>();
     private final HashMap<GpsStatus.NmeaListener, GnssStatusListenerTransport> mGpsNmeaListeners =
             new HashMap<>();
-    private final HashMap<GnssStatusCallback, GnssStatusListenerTransport> mGnssStatusListeners =
+    private final HashMap<GnssStatusCallback, GnssStatusListenerTransport>
+            mOldGnssStatusListeners = new HashMap<>();
+    private final HashMap<GnssStatus.Callback, GnssStatusListenerTransport> mGnssStatusListeners =
             new HashMap<>();
-    private final HashMap<GnssNmeaListener, GnssStatusListenerTransport> mGnssNmeaListeners =
+    private final HashMap<GnssNmeaListener, GnssStatusListenerTransport> mOldGnssNmeaListeners =
             new HashMap<>();
+    private final HashMap<OnNmeaMessageListener, GnssStatusListenerTransport> mGnssNmeaListeners =
+            new HashMap<>();
+    private final HashMap<GnssNavigationMessageEvent.Callback, GnssNavigationMessage.Callback>
+            mNavigationMessageBridge = new HashMap<>();
     private GnssStatus mGnssStatus;
     private int mTimeToFirstFix;
 
@@ -1392,8 +1398,10 @@
 
         private final GpsStatus.Listener mGpsListener;
         private final GpsStatus.NmeaListener mGpsNmeaListener;
-        private final GnssStatusCallback mGnssCallback;
-        private final GnssNmeaListener mGnssNmeaListener;
+        private final GnssStatusCallback mOldGnssCallback;
+        private final GnssStatus.Callback mGnssCallback;
+        private final GnssNmeaListener mOldGnssNmeaListener;
+        private final OnNmeaMessageListener mGnssNmeaListener;
 
         private class GnssHandler extends Handler {
             public GnssHandler(Handler handler) {
@@ -1408,7 +1416,7 @@
                             int length = mNmeaBuffer.size();
                             for (int i = 0; i < length; i++) {
                                 Nmea nmea = mNmeaBuffer.get(i);
-                                mGnssNmeaListener.onNmeaReceived(nmea.mTimestamp, nmea.mNmea);
+                                mGnssNmeaListener.onNmeaMessage(nmea.mNmea, nmea.mTimestamp);
                             }
                             mNmeaBuffer.clear();
                         }
@@ -1456,7 +1464,8 @@
             mGnssHandler = new GnssHandler(handler);
             mGpsNmeaListener = null;
             mNmeaBuffer = null;
-            mGnssCallback = new GnssStatusCallback() {
+            mOldGnssCallback = null;
+            mGnssCallback = new GnssStatus.Callback() {
                 @Override
                 public void onStarted() {
                     mGpsListener.onGpsStatusChanged(GpsStatus.GPS_EVENT_STARTED);
@@ -1477,6 +1486,7 @@
                     mGpsListener.onGpsStatusChanged(GpsStatus.GPS_EVENT_SATELLITE_STATUS);
                 }
             };
+            mOldGnssNmeaListener = null;
             mGnssNmeaListener = null;
         }
 
@@ -1489,10 +1499,12 @@
             mGnssHandler = new GnssHandler(handler);
             mGpsNmeaListener = listener;
             mNmeaBuffer = new ArrayList<Nmea>();
+            mOldGnssCallback = null;
             mGnssCallback = null;
-            mGnssNmeaListener = new GnssNmeaListener() {
+            mOldGnssNmeaListener = null;
+            mGnssNmeaListener = new OnNmeaMessageListener() {
                 @Override
-                public void onNmeaReceived(long timestamp, String nmea) {
+                public void onNmeaMessage(String nmea, long timestamp) {
                     mGpsNmeaListener.onNmeaReceived(timestamp, nmea);
                 }
             };
@@ -1503,8 +1515,45 @@
         }
 
         GnssStatusListenerTransport(GnssStatusCallback callback, Handler handler) {
+            mOldGnssCallback = callback;
+            mGnssCallback = new GnssStatus.Callback() {
+                @Override
+                public void onStarted() {
+                    mOldGnssCallback.onStarted();
+                }
+
+                @Override
+                public void onStopped() {
+                    mOldGnssCallback.onStopped();
+                }
+
+                @Override
+                public void onFirstFix(int ttff) {
+                    mOldGnssCallback.onFirstFix(ttff);
+                }
+
+                @Override
+                public void onSatelliteStatusChanged(GnssStatus status) {
+                    mOldGnssCallback.onSatelliteStatusChanged(status);
+                }
+            };
+            mGnssHandler = new GnssHandler(handler);
+            mOldGnssNmeaListener = null;
+            mGnssNmeaListener = null;
+            mNmeaBuffer = null;
+            mGpsListener = null;
+            mGpsNmeaListener = null;
+        }
+
+        GnssStatusListenerTransport(GnssStatus.Callback callback) {
+            this(callback, null);
+        }
+
+        GnssStatusListenerTransport(GnssStatus.Callback callback, Handler handler) {
+            mOldGnssCallback = null;
             mGnssCallback = callback;
             mGnssHandler = new GnssHandler(handler);
+            mOldGnssNmeaListener = null;
             mGnssNmeaListener = null;
             mNmeaBuffer = null;
             mGpsListener = null;
@@ -1517,7 +1566,29 @@
 
         GnssStatusListenerTransport(GnssNmeaListener listener, Handler handler) {
             mGnssCallback = null;
+            mOldGnssCallback = null;
             mGnssHandler = new GnssHandler(handler);
+            mOldGnssNmeaListener = listener;
+            mGnssNmeaListener = new OnNmeaMessageListener() {
+                @Override
+                public void onNmeaMessage(String message, long timestamp) {
+                    mOldGnssNmeaListener.onNmeaReceived(timestamp, message);
+                }
+            };
+            mGpsListener = null;
+            mGpsNmeaListener = null;
+            mNmeaBuffer = new ArrayList<Nmea>();
+        }
+
+        GnssStatusListenerTransport(OnNmeaMessageListener listener) {
+            this(listener, null);
+        }
+
+        GnssStatusListenerTransport(OnNmeaMessageListener listener, Handler handler) {
+            mOldGnssCallback = null;
+            mGnssCallback = null;
+            mGnssHandler = new GnssHandler(handler);
+            mOldGnssNmeaListener = null;
             mGnssNmeaListener = listener;
             mGpsListener = null;
             mGpsNmeaListener = null;
@@ -1589,7 +1660,7 @@
      * @return true if the listener was successfully added
      *
      * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
-     * @deprecated use {@link #registerGnssStatusCallback(GnssStatusCallback)} instead.
+     * @deprecated use {@link #registerGnssStatusCallback(GnssStatus.Callback)} instead.
      */
     @Deprecated
     @RequiresPermission(ACCESS_FINE_LOCATION)
@@ -1617,6 +1688,7 @@
      * Removes a GPS status listener.
      *
      * @param listener GPS status listener object to remove
+     * @deprecated use {@link #unregisterGnssStatusCallback(GnssStatus.Callback)} instead.
      */
     @Deprecated
     public void removeGpsStatusListener(GpsStatus.Listener listener) {
@@ -1630,7 +1702,6 @@
         }
     }
 
-
     /**
      * Registers a GNSS status listener.
      *
@@ -1639,6 +1710,7 @@
      * @return true if the listener was successfully added
      *
      * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
+     * @removed
      */
     @RequiresPermission(ACCESS_FINE_LOCATION)
     public boolean registerGnssStatusCallback(GnssStatusCallback callback) {
@@ -1654,10 +1726,73 @@
      * @return true if the listener was successfully added
      *
      * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
+     * @removed
      */
     @RequiresPermission(ACCESS_FINE_LOCATION)
     public boolean registerGnssStatusCallback(GnssStatusCallback callback, Handler handler) {
         boolean result;
+        if (mOldGnssStatusListeners.get(callback) != null) {
+            // listener is already registered
+            return true;
+        }
+        try {
+            GnssStatusListenerTransport transport =
+                    new GnssStatusListenerTransport(callback, handler);
+            result = mService.registerGnssStatusCallback(transport, mContext.getPackageName());
+            if (result) {
+                mOldGnssStatusListeners.put(callback, transport);
+            }
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+
+        return result;
+    }
+
+    /**
+     * Removes a GNSS status listener.
+     *
+     * @param callback GNSS status listener object to remove
+     * @removed
+     */
+    public void unregisterGnssStatusCallback(GnssStatusCallback callback) {
+        try {
+            GnssStatusListenerTransport transport = mOldGnssStatusListeners.remove(callback);
+            if (transport != null) {
+                mService.unregisterGnssStatusCallback(transport);
+            }
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Registers a GNSS status listener.
+     *
+     * @param callback GNSS status listener object to register
+     *
+     * @return true if the listener was successfully added
+     *
+     * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
+     */
+    @RequiresPermission(ACCESS_FINE_LOCATION)
+    public boolean registerGnssStatusCallback(GnssStatus.Callback callback) {
+        return registerGnssStatusCallback(callback, null);
+    }
+
+    /**
+     * Registers a GNSS status listener.
+     *
+     * @param callback GNSS status listener object to register
+     * @param handler the handler that the callback runs on.
+     *
+     * @return true if the listener was successfully added
+     *
+     * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
+     */
+    @RequiresPermission(ACCESS_FINE_LOCATION)
+    public boolean registerGnssStatusCallback(GnssStatus.Callback callback, Handler handler) {
+        boolean result;
         if (mGnssStatusListeners.get(callback) != null) {
             // listener is already registered
             return true;
@@ -1681,7 +1816,7 @@
      *
      * @param callback GNSS status listener object to remove
      */
-    public void unregisterGnssStatusCallback(GnssStatusCallback callback) {
+    public void unregisterGnssStatusCallback(GnssStatus.Callback callback) {
         try {
             GnssStatusListenerTransport transport = mGnssStatusListeners.remove(callback);
             if (transport != null) {
@@ -1700,7 +1835,7 @@
      * @return true if the listener was successfully added
      *
      * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
-     * @deprecated use {@link #addNmeaListener(GnssNmeaListener)} instead.
+     * @deprecated use {@link #addNmeaListener(OnNmeaMessageListener)} instead.
      */
     @Deprecated
     @RequiresPermission(ACCESS_FINE_LOCATION)
@@ -1728,6 +1863,7 @@
      * Removes an NMEA listener.
      *
      * @param listener a {@link GpsStatus.NmeaListener} object to remove
+     * @deprecated use {@link #removeNmeaListener(OnNmeaMessageListener)} instead.
      */
     @Deprecated
     public void removeNmeaListener(GpsStatus.NmeaListener listener) {
@@ -1749,6 +1885,7 @@
      * @return true if the listener was successfully added
      *
      * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
+     * @removed
      */
     @RequiresPermission(ACCESS_FINE_LOCATION)
     public boolean addNmeaListener(GnssNmeaListener listener) {
@@ -1764,6 +1901,7 @@
      * @return true if the listener was successfully added
      *
      * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
+     * @removed
      */
     @RequiresPermission(ACCESS_FINE_LOCATION)
     public boolean addNmeaListener(GnssNmeaListener listener, Handler handler) {
@@ -1778,6 +1916,69 @@
                     new GnssStatusListenerTransport(listener, handler);
             result = mService.registerGnssStatusCallback(transport, mContext.getPackageName());
             if (result) {
+                mOldGnssNmeaListeners.put(listener, transport);
+            }
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+
+        return result;
+    }
+
+    /**
+     * Removes an NMEA listener.
+     *
+     * @param listener a {@link GnssNmeaListener} object to remove
+     * @removed
+     */
+    public void removeNmeaListener(GnssNmeaListener listener) {
+        try {
+            GnssStatusListenerTransport transport = mOldGnssNmeaListeners.remove(listener);
+            if (transport != null) {
+                mService.unregisterGnssStatusCallback(transport);
+            }
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Adds an NMEA listener.
+     *
+     * @param listener a {@link OnNmeaMessageListener} object to register
+     *
+     * @return true if the listener was successfully added
+     *
+     * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
+     */
+    @RequiresPermission(ACCESS_FINE_LOCATION)
+    public boolean addNmeaListener(OnNmeaMessageListener listener) {
+        return addNmeaListener(listener, null);
+    }
+
+    /**
+     * Adds an NMEA listener.
+     *
+     * @param listener a {@link OnNmeaMessageListener} object to register
+     * @param handler the handler that the listener runs on.
+     *
+     * @return true if the listener was successfully added
+     *
+     * @throws SecurityException if the ACCESS_FINE_LOCATION permission is not present
+     */
+    @RequiresPermission(ACCESS_FINE_LOCATION)
+    public boolean addNmeaListener(OnNmeaMessageListener listener, Handler handler) {
+        boolean result;
+
+        if (mGpsNmeaListeners.get(listener) != null) {
+            // listener is already registered
+            return true;
+        }
+        try {
+            GnssStatusListenerTransport transport =
+                    new GnssStatusListenerTransport(listener, handler);
+            result = mService.registerGnssStatusCallback(transport, mContext.getPackageName());
+            if (result) {
                 mGnssNmeaListeners.put(listener, transport);
             }
         } catch (RemoteException e) {
@@ -1790,9 +1991,9 @@
     /**
      * Removes an NMEA listener.
      *
-     * @param listener a {@link GnssNmeaListener} object to remove
+     * @param listener a {@link OnNmeaMessageListener} object to remove
      */
-    public void removeNmeaListener(GnssNmeaListener listener) {
+    public void removeNmeaListener(OnNmeaMessageListener listener) {
         try {
             GnssStatusListenerTransport transport = mGnssNmeaListeners.remove(listener);
             if (transport != null) {
@@ -1843,7 +2044,8 @@
      * No-op method to keep backward-compatibility.
      * Don't use it. Use {@link #unregisterGnssMeasurementsCallback} instead.
      * @hide
-     * @deprecated
+     * @deprecated use {@link #unregisterGnssMeasurementsCallback(GnssMeasurementsEvent.Callback)}
+     * instead.
      */
     @Deprecated
     @SystemApi
@@ -1872,10 +2074,23 @@
     }
 
     /**
-     * Registers a GPS Navigation Message callback.
+     * No-op method to keep backward-compatibility.
+     * Don't use it. Use {@link #unregisterGnssNavigationMessageCallback} instead.
+     * @hide
+     * @deprecated use {@link #unregisterGnssNavigationMessageCallback(GnssMeasurements.Callback)}
+     * instead
+     */
+    @Deprecated
+    @SystemApi
+    public void removeGpsNavigationMessageListener(GpsNavigationMessageEvent.Listener listener) {
+    }
+
+    /**
+     * Registers a GNSS Navigation Message callback.
      *
      * @param callback a {@link GnssNavigationMessageEvent.Callback} object to register.
      * @return {@code true} if the callback was added successfully, {@code false} otherwise.
+     * @removed
      */
     public boolean registerGnssNavigationMessageCallback(
             GnssNavigationMessageEvent.Callback callback) {
@@ -1883,40 +2098,80 @@
     }
 
     /**
-     * Registers a GPS Navigation Message callback.
+     * Registers a GNSS Navigation Message callback.
      *
      * @param callback a {@link GnssNavigationMessageEvent.Callback} object to register.
      * @param handler the handler that the callback runs on.
      * @return {@code true} if the callback was added successfully, {@code false} otherwise.
+     * @removed
+     */
+    @RequiresPermission(ACCESS_FINE_LOCATION)
+    public boolean registerGnssNavigationMessageCallback(
+            final GnssNavigationMessageEvent.Callback callback, Handler handler) {
+        GnssNavigationMessage.Callback bridge = new GnssNavigationMessage.Callback() {
+            @Override
+            public void onGnssNavigationMessageReceived(GnssNavigationMessage message) {
+                GnssNavigationMessageEvent event = new GnssNavigationMessageEvent(message);
+                callback.onGnssNavigationMessageReceived(event);
+            }
+
+            @Override
+            public void onStatusChanged(int status) {
+                callback.onStatusChanged(status);
+            }
+        };
+        mNavigationMessageBridge.put(callback, bridge);
+        return mGnssNavigationMessageCallbackTransport.add(bridge, handler);
+    }
+
+    /**
+     * Unregisters a GNSS Navigation Message callback.
+     *
+     * @param callback a {@link GnssNavigationMessageEvent.Callback} object to remove.
+     * @removed
+     */
+    public void unregisterGnssNavigationMessageCallback(
+            GnssNavigationMessageEvent.Callback callback) {
+        mGnssNavigationMessageCallbackTransport.remove(
+                mNavigationMessageBridge.remove(
+                        callback));
+    }
+
+    /**
+     * Registers a GNSS Navigation Message callback.
+     *
+     * @param callback a {@link GnssNavigationMessage.Callback} object to register.
+     * @return {@code true} if the callback was added successfully, {@code false} otherwise.
+     */
+    public boolean registerGnssNavigationMessageCallback(
+            GnssNavigationMessage.Callback callback) {
+        return registerGnssNavigationMessageCallback(callback, null);
+    }
+
+    /**
+     * Registers a GNSS Navigation Message callback.
+     *
+     * @param callback a {@link GnssNavigationMessage.Callback} object to register.
+     * @param handler the handler that the callback runs on.
+     * @return {@code true} if the callback was added successfully, {@code false} otherwise.
      */
     @RequiresPermission(ACCESS_FINE_LOCATION)
     public boolean registerGnssNavigationMessageCallback(
-            GnssNavigationMessageEvent.Callback callback, Handler handler) {
+            GnssNavigationMessage.Callback callback, Handler handler) {
         return mGnssNavigationMessageCallbackTransport.add(callback, handler);
     }
 
     /**
-     * Unregisters a GPS Navigation Message callback.
+     * Unregisters a GNSS Navigation Message callback.
      *
-     * @param callback a {@link GnssNavigationMessageEvent.Callback} object to remove.
+     * @param callback a {@link GnssNavigationMessage.Callback} object to remove.
      */
     public void unregisterGnssNavigationMessageCallback(
-            GnssNavigationMessageEvent.Callback callback) {
+            GnssNavigationMessage.Callback callback) {
         mGnssNavigationMessageCallbackTransport.remove(callback);
     }
 
     /**
-     * No-op method to keep backward-compatibility.
-     * Don't use it. Use {@link #unregisterGnssNavigationMessageCallback} instead.
-     * @hide
-     * @deprecated
-     */
-    @Deprecated
-    @SystemApi
-    public void removeGpsNavigationMessageListener(GpsNavigationMessageEvent.Listener listener) {
-    }
-
-    /**
      * Retrieves information about the current status of the GPS engine.
      * This should only be called from the {@link GpsStatus.Listener#onGpsStatusChanged}
      * callback to ensure that the data is copied atomically.
diff --git a/location/java/android/location/OnNmeaMessageListener.java b/location/java/android/location/OnNmeaMessageListener.java
new file mode 100644
index 0000000..ccf6ce8
--- /dev/null
+++ b/location/java/android/location/OnNmeaMessageListener.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.location;
+
+/**
+* Used for receiving NMEA sentences from the GNSS.
+* NMEA 0183 is a standard for communicating with marine electronic devices
+* and is a common method for receiving data from a GNSS, typically over a serial port.
+* See <a href="http://en.wikipedia.org/wiki/NMEA_0183">NMEA 0183</a> for more details.
+* You can implement this interface and call {@link LocationManager#addNmeaListener}
+* to receive NMEA data from the GNSS engine.
+*/
+public interface OnNmeaMessageListener {
+    /**
+     * Called when an NMEA message is received.
+     * @param message NMEA message
+     * @param timestamp milliseconds since January 1, 1970.
+     */
+    void onNmeaMessage(String message, long timestamp);
+}
diff --git a/services/core/java/com/android/server/location/GnssLocationProvider.java b/services/core/java/com/android/server/location/GnssLocationProvider.java
index e08fad4..6b916be 100644
--- a/services/core/java/com/android/server/location/GnssLocationProvider.java
+++ b/services/core/java/com/android/server/location/GnssLocationProvider.java
@@ -39,7 +39,7 @@
 import android.location.IGnssStatusListener;
 import android.location.IGnssStatusProvider;
 import android.location.GnssMeasurementsEvent;
-import android.location.GnssNavigationMessageEvent;
+import android.location.GnssNavigationMessage;
 import android.location.IGpsGeofenceHardware;
 import android.location.ILocationManager;
 import android.location.INetInitiatedListener;
@@ -1662,7 +1662,7 @@
     /**
      * called from native code - GPS navigation message callback
      */
-    private void reportNavigationMessage(GnssNavigationMessageEvent event) {
+    private void reportNavigationMessage(GnssNavigationMessage event) {
         mGnssNavigationMessageProvider.onNavigationMessageAvailable(event);
     }
 
diff --git a/services/core/java/com/android/server/location/GnssMeasurementsProvider.java b/services/core/java/com/android/server/location/GnssMeasurementsProvider.java
index 734a8d4..caf1d6c 100644
--- a/services/core/java/com/android/server/location/GnssMeasurementsProvider.java
+++ b/services/core/java/com/android/server/location/GnssMeasurementsProvider.java
@@ -64,15 +64,15 @@
         int status;
         switch (result) {
             case RESULT_SUCCESS:
-                status = GnssMeasurementsEvent.STATUS_READY;
+                status = GnssMeasurementsEvent.Callback.STATUS_READY;
                 break;
             case RESULT_NOT_AVAILABLE:
             case RESULT_NOT_SUPPORTED:
             case RESULT_INTERNAL_ERROR:
-                status = GnssMeasurementsEvent.STATUS_NOT_SUPPORTED;
+                status = GnssMeasurementsEvent.Callback.STATUS_NOT_SUPPORTED;
                 break;
             case RESULT_GPS_LOCATION_DISABLED:
-                status = GnssMeasurementsEvent.STATUS_GNSS_LOCATION_DISABLED;
+                status = GnssMeasurementsEvent.Callback.STATUS_LOCATION_DISABLED;
                 break;
             case RESULT_UNKNOWN:
                 return null;
diff --git a/services/core/java/com/android/server/location/GnssNavigationMessageProvider.java b/services/core/java/com/android/server/location/GnssNavigationMessageProvider.java
index fdef31f..8d21928 100644
--- a/services/core/java/com/android/server/location/GnssNavigationMessageProvider.java
+++ b/services/core/java/com/android/server/location/GnssNavigationMessageProvider.java
@@ -16,7 +16,7 @@
 
 package com.android.server.location;
 
-import android.location.GnssNavigationMessageEvent;
+import android.location.GnssNavigationMessage;
 import android.location.IGnssNavigationMessageListener;
 import android.os.Handler;
 import android.os.RemoteException;
@@ -37,7 +37,7 @@
         super(handler, TAG);
     }
 
-    public void onNavigationMessageAvailable(final GnssNavigationMessageEvent event) {
+    public void onNavigationMessageAvailable(final GnssNavigationMessage event) {
         ListenerOperation<IGnssNavigationMessageListener> operation =
                 new ListenerOperation<IGnssNavigationMessageListener>() {
                     @Override
@@ -65,16 +65,15 @@
         int status;
         switch (result) {
             case RESULT_SUCCESS:
-                status = GnssNavigationMessageEvent.STATUS_READY;
+                status = GnssNavigationMessage.Callback.STATUS_READY;
                 break;
             case RESULT_NOT_AVAILABLE:
             case RESULT_NOT_SUPPORTED:
             case RESULT_INTERNAL_ERROR:
-                status = GnssNavigationMessageEvent.STATUS_NOT_SUPPORTED;
+                status = GnssNavigationMessage.Callback.STATUS_NOT_SUPPORTED;
                 break;
             case RESULT_GPS_LOCATION_DISABLED:
-                status = GnssNavigationMessageEvent
-                        .STATUS_GNSS_LOCATION_DISABLED;
+                status = GnssNavigationMessage.Callback.STATUS_LOCATION_DISABLED;
                 break;
             case RESULT_UNKNOWN:
                 return null;