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Android - problems with the Fused Location API with satellite information (account, signal, etc.)

I am working on a project in which we are trying to track the position of the device and store data for later use. Before I talk about the problem, I would like to dwell on some background.

Looking around StackExchange and Google and everywhere, I came to the conclusion that it is almost impossible to get satellite information using the Fused Location API (Google works well there).

The method used by most people is to actually use the LocationManager near the Fused location to obtain GPS status. My first question comes here: How can we be 100% sure that the numbers provided by LocationManager are in sync with what Fused Location provided us with? Does the manager use the floating location inside himself?

And now the problem. The app uses an “always on” sticky service to raise positions no matter what. When there are no satellites, everything works as intended. Place the device in a position where it can see satellites, it does not have a lock. Using the debugger, GpsStatus.getSatellites () displays an empty list. Now, without moving the device, I launch the Compass application (according to Catch.com, since there are many of them), which has a GPS-type compass diagram. This blocks the satellites and quite quickly, and from now on, satellites are also reported in my application. If the compass is closed, the application is stuck on the last number provided by the compass !!! The device that I personally use for testing is the Nexus 7 2013 with the latest official updates (Android 6.0.1).

Here is the code:

public class BackgroundLocationService extends Service implements
    GoogleApiClient.ConnectionCallbacks,
    GoogleApiClient.OnConnectionFailedListener,
    GpsStatus.Listener,
    LocationListener {

// Constants here....

private GoogleApiClient mGoogleApiClient;
private LocationRequest mLocationRequest;
private LocationManager locationManager;
// Flag that indicates if a request is underway.
private boolean mInProgress;

private NotificationManagement myNotificationManager;
private Boolean servicesAvailable = false;

//And other variables here...

@Override
public void onCreate()
{
    super.onCreate();

    myNotificationManager = new NotificationManagement(getApplicationContext());
    myNotificationManager.displayMainNotification();

    mInProgress = false;
    // Create the LocationRequest object
    mLocationRequest = LocationRequest.create();
    // Use high accuracy
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    // Set the update interval
    mLocationRequest.setInterval(PREFERRED_INTERVAL);
    // Set the fastest update interval
    mLocationRequest.setFastestInterval(FASTEST_INTERVAL);

    servicesAvailable = servicesConnected();

    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    locationManager.addGpsStatusListener(this);

    setUpLocationClientIfNeeded();
}

/**
 * Create a new location client, using the enclosing class to
 * handle callbacks.
 */
protected synchronized void buildGoogleApiClient()
{
    this.mGoogleApiClient = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API)
            .build();
}

private boolean servicesConnected()
{

    // Check that Google Play services is available
    int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);

    // If Google Play services is available
    if (ConnectionResult.SUCCESS == resultCode)
    {
        return true;
    }
    else
    {
        return false;
    }
}

public int onStartCommand(Intent intent, int flags, int startId)
{
    super.onStartCommand(intent, flags, startId);

    if (!servicesAvailable || mGoogleApiClient.isConnected() || mInProgress)
        return START_STICKY;

    setUpLocationClientIfNeeded();
    if (!mGoogleApiClient.isConnected() || !mGoogleApiClient.isConnecting() && !mInProgress)
    {
        mInProgress = true;
        mGoogleApiClient.connect();
    }
    return START_STICKY;
}


private void setUpLocationClientIfNeeded()
{
    if (mGoogleApiClient == null)
        buildGoogleApiClient();
}

public void onGpsStatusChanged(int event)
{

}

// Define the callback method that receives location updates
@Override
public void onLocationChanged(Location location)
{
    simpleGPSFilter(location);
}

// Other fancy and needed stuff here...

/**
 * "Stupid" filter that utilizes experience data to filter out location noise.
 * @param location Location object carrying all the needed information
 */
private void simpleGPSFilter(Location location)
{
    //Loading all the required variables
    int signalPower = 0;
    satellites = 0;
    // Getting the satellites
    mGpsStatus = locationManager.getGpsStatus(mGpsStatus);
    Iterable<GpsSatellite> sats = mGpsStatus.getSatellites();
    if (sats != null)
    {
        for (GpsSatellite sat : sats)
        {
            if (sat.usedInFix())
            {
                satellites++;
                signalPower += sat.getSnr();
            }
        }
    }
    if (satellites != 0)
        signalPower = signalPower/satellites;
    mySpeed = (location.getSpeed() * 3600) / 1000;
    myAccuracy = location.getAccuracy();
    myBearing = location.getBearing();
    latitude = location.getLatitude();
    longitude = location.getLongitude();
    Log.i("START OF CYCLE", "START OF CYCLE");
    Log.i("Sat Strength", Integer.toString(signalPower));
    Log.i("Locked Sats", Integer.toString(satellites));

    // Do the math for the coordinates distance
    /*
     * Earth radius at given Latitude.
     * Formula: Radius = sqrt( ((equatorR^2 * cos(latitude))^2 + (poleR^2 * sin(latitude))^2 ) / ((equatorR * cos(latitude))^2 + (poleR * sin(latitude))^2)
     * IMPORTANT: Math lib uses radians for the trigonometry equations so do not forget to use toRadians()
     */
    Log.i("Lat for Radius", Double.toString(latitude));
    double earthRadius = Math.sqrt((Math.pow((EARTH_RADIUS_EQUATOR * EARTH_RADIUS_EQUATOR * Math.cos(Math.toRadians(latitude))), 2)
            + Math.pow((EARTH_RADIUS_POLES * EARTH_RADIUS_POLES * Math.cos(Math.toRadians(latitude))), 2))
            / (Math.pow((EARTH_RADIUS_EQUATOR * Math.cos(Math.toRadians(latitude))), 2)
            + Math.pow((EARTH_RADIUS_POLES * Math.cos(Math.toRadians(latitude))), 2)));
    Log.i("Earth Radius", Double.toString(earthRadius));

    /*
     * Calculating distance between 2 points on map using the Haversine formula (arctangent writing) with the following algorithm
     * latDifference = latitude - lastLatitude;
     * lngDifference = longitude - lastLongitude;
     * a = (sin(latDifference/2))^2 + cos(lastLatitude) * cos(latitude) * (sin(lngDifference/2))^2
     * c = 2 * atan2( sqrt(a), sqrt(1-a) )
     * distance = earthRadius * c
     */
    double latDifference = latitude - lastLatitude;
    double lngDifference = longitude - lastLongitude;
    double a = Math.pow((Math.sin(Math.toRadians(latDifference / 2))), 2) + (Math.cos(Math.toRadians(lastLatitude))
            * Math.cos(Math.toRadians(latitude))
            * Math.pow((Math.sin(Math.toRadians(lngDifference / 2))), 2));
    double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
    double distance = earthRadius * c;
    Log.i("New point distance", Double.toString(distance));

    // Filter logic
    // Make an initial location log
    if ((!isInit) && (myAccuracy < ACCEPTED_ACCURACY))
    {
        isInit = true;
        lastLatitude = latitude;
        lastLongitude = longitude;
        logLocations(location);
    }
    else
    {
        // Satellite lock (use of GPS) on the higher level
        if (satellites == 0)
        {
            // Accuracy filtering at the second level
            if (myAccuracy < ACCEPTED_ACCURACY)
            {
                if ((distance > ACCEPTED_DISTANCE))
                {
                    lastLatitude = latitude;
                    lastLongitude = longitude;
                    logLocations(location);
                    Log.i("Location Logged", "No Sats");
                    /*
                    // Calculate speed in correlation to perceived movement
                    double speed = distance / (PREFERRED_INTERVAL / 1000);  // TODO: Need to make actual time dynamic as the fused location does not have fixed timing
                    if (speed < ACCEPTED_SPEED)
                    {
                        lastLatitude = latitude;
                        lastLongitude = longitude;
                        logLocations(location);
                    } */
                }
            }
        }
        else if ((satellites < 4) && (signalPower > ACCEPTED_SIGNAL))
        {
            if (myAccuracy < (ACCEPTED_ACCURACY + 50))
            {
                logLocations(location);
                Log.i("Location Logged", "With Sats");
            }
        }
        else
        {
            if (myAccuracy < (ACCEPTED_ACCURACY + 100))
            {
                lastSpeed = mySpeed;
                lastBearing = myBearing;
                lastLatitude = latitude;
                lastLongitude = longitude;
                logLocations(location);
                Log.i("Location Logged", "With Good Sats");
            }
        }
    }
    Log.i("END OF CYCLE", "END OF CYCLE");
}

private void logLocations(Location location)
{
    String myprovider = "false";

    String temp = timestampFormat.format(location.getTime());
    MySQLiteHelper dbHelper = new MySQLiteHelper(getApplicationContext());

    try
    {
        dbHelper.createEntry(latitude, longitude, allschemes, temp, mySpeed, myAccuracy, myBearing, myprovider, satellites);
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }

    CheckAutoArrive(String.valueOf(latitude), String.valueOf(longitude));

}

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Source: https://habr.com/ru/post/1658371/

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