如何使用 GnssMeasurement 回调获取 Android 7.0 中每个检测到的 GPS 卫星的 SNR？

Question

在下面显示的代码中，我可以使用GnssStatus.callback获取 Android 7.0 及更高版本 API 中可见卫星的数量。但我无法获取每个检测到的卫星的相关 SNR，因为GnssStatus.callback不支持函数。

我检查了此链接，发现我们应该使用GnssMeasurement回调并调用 ( getsnrindb() )，如下所示。

如何使用（GnssMeasurement 回调）获取 SNR 值？

我的代码：

    tv1 = (TextView) findViewById(R.id.Gps_location);
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    mGnssStatusCallback = new GnssStatus.Callback() {
        // TODO: add your code here!
        @Override
        public void onSatelliteStatusChanged(GnssStatus status) {

            satelliteCount = status.getSatelliteCount();
            sat_id = status.getSvid(1);
            constellationType = status.getConstellationType(1);
            v = " Scan: "+ (count)+  " ,Sat-count=" +(satelliteCount) +"id="+ sat_id +" type"+  constellationType + " ,Eacc= "+accuracy+ "\n\n";
            v += tv1.getText();
            tv1.setText(v);
            count= count + 1;
        }
    };


 @Override
protected void onStart() {
    super.onStart();
    mLocationManager.registerGnssStatusCallback(mGnssStatusCallback);
    mLocationManager.registerGnssMeasurementsCallback(mGnssMeasurmentscallbak);
    mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 30000, 0, this);
}

@Override
protected void onStop() {
    mLocationManager.removeUpdates(this);
    mLocationManager.unregisterGnssStatusCallback(
            mGnssStatusCallback
            );
    super.onStop();
}
@Override
public void onLocationChanged(Location location) {
    // TODO Auto-generated method stub
    if (locationManager != null) {
        location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        if (location != null) {
            latitude = location.getLatitude();  
            longitude = location.getLongitude();
            accuracy = location.getAccuracy();
        }
    }

}

Answer 1

使用 GnssStatus.Callback() 和 getSatelliteCount() 计算 GPS 信号强度，这为我们提供了我们范围内的卫星数量，并且每个卫星都有一个信噪比 (getCn0DbHz(i))。

// Android N (7.0) 及以上状态和监听器

    private GnssStatus.Callback mGnssStatusCallback ;

    mGnssStatusCallback = new GnssStatus.Callback() {

        @Override
        public void onSatelliteStatusChanged(GnssStatus status) {

            int satelliteCount = status.getSatelliteCount();

            int usedSatellites = 0;
            float totalSnr = 0;
            for (int i = 0; i < satelliteCount; i++){
                if (status.usedInFix(i)) {
                    usedSatellites++;
                    totalSnr += status.getCn0DbHz(i); //this method obtains the signal from each satellite
                }
            }
            // we calculate the average of the power of the GPS signal
            float avgSnr = (usedSatellites > 0) ? totalSnr / usedSatellites: 0.0f;


            Log.d(TAG, "Number used satelites: " + usedSatellites + " SNR: " + totalSnr+"avg SNR: "+avgSnr);
        }
    };
    try {
        mLocationManager.registerGnssStatusCallback(mGnssStatusCallback);
    } catch (SecurityException e) {
        Log.e(TAG,"Error "+e);
    }