public override void updateMeasurements(GnssMeasurementsEvent evento)
{
lock (this) {
visibleButNotUsed = 0;
observedSatellites.Clear();
unusedSatellites.Clear();
GnssClock gnssClock = evento.Clock;
long TimeNanos = gnssClock.TimeNanos;
timeRefMsec = new Time(JavaSystem.CurrentTimeMillis());
double BiasNanos = gnssClock.BiasNanos;
double galileoTime, pseudorangeTOW, pseudorangeE1_2nd, tTxGalileo;
// Use only the first instance of the FullBiasNanos (as done in gps-measurement-tools)
if (!fullBiasNanosInitialized)
{
FullBiasNanos = gnssClock.FullBiasNanos;
fullBiasNanosInitialized = true;
}
// Start computing the pseudoranges using the raw data from the phone's GNSS receiver
foreach (GnssMeasurement measurement in evento.Measurements)
{
if (measurement.ConstellationType != constellationId)
{
continue;
}
if (measurement.HasCarrierFrequencyHz)
{
if (!approximateEqual(measurement.CarrierFrequencyHz, E1a_FREQUENCY, FREQUENCY_MATCH_RANGE))
{
continue;
}
}
long ReceivedSvTimeNanos = measurement.ReceivedSvTimeNanos;
double TimeOffsetNanos = measurement.TimeOffsetNanos;
// Galileo Time generation (GSA White Paper - page 20)
galileoTime = TimeNanos - (FullBiasNanos + BiasNanos);
// Compute the time of signal reception for when GNSS_MEASUREMENT_STATE_TOW_KNOWN or GNSS_MEASUREMENT_STATE_TOW_DECODED are true
tRxGalileoTOW = galileoTime % Constants.NUMBER_NANO_SECONDS_PER_WEEK;
// Measurement time in full Galileo time without taking into account weekNumberNanos(the number of
// nanoseconds that have occurred from the beginning of GPS time to the current
// week number)
weekNumber = System.Math.Floor((-1.0 * FullBiasNanos) / Constants.NUMBER_NANO_SECONDS_PER_WEEK);
// Compute the signal reception for when GNSS_MEASUREMENT_STATE_GAL_E1C_2ND_CODE_LOCK is true
tRxGalileoE1_2nd = galileoTime % Constants.NumberNanoSeconds100Milli;
tTxGalileo = ReceivedSvTimeNanos + TimeOffsetNanos;
// Valid only if GNSS_MEASUREMENT_STATE_TOW_KNOWN or GNSS_MEASUREMENT_STATE_TOW_DECODED are true
pseudorangeTOW = (tRxGalileoTOW - tTxGalileo) * 1e-9 * Constants.SPEED_OF_LIGHT;
// Valid only if GNSS_MEASUREMENT_STATE_GAL_E1C_2ND_CODE_LOCK
pseudorangeE1_2nd = ((galileoTime - tTxGalileo) % Constants.NumberNanoSeconds100Milli) * 1e-9 * Constants.SPEED_OF_LIGHT;
/*
*
* According to https://developer.android.com/ and GSA White Paper (pg.20)
* the GnssMeasurements States required for GALILEO valid pseudoranges are:
*
* STATE_TOW_KNOWN = 16384 (1 << 11)
* STATE_TOW_DECODED = 8 (1 << 3)
* STATE_GAL_E1C_2ND_CODE_LOCK = 2048 (1 << 11)
*
*/
// Get the measurement state
GnssState measState = measurement.State;
// Bitwise AND to identify the states
bool towKnown = false;
if (Android.OS.Build.VERSION.SdkInt >= BuildVersionCodes.O)
{
towKnown = (measState & GnssState.TowKnown) != 0;
}
bool towDecoded = (measState & GnssState.TowDecoded) != 0;
bool codeLockE1BC = (measState & GnssState.GalE1bcCodeLock) != 0;
bool codeLockE1C = (measState & GnssState.GalE1c2ndCodeLock) != 0;
// Variables for debugging
double prTOW = pseudorangeTOW;
double prE1_2nd = pseudorangeE1_2nd;
double diffPR = prTOW - prE1_2nd;
int svID = measurement.Svid;
if (towDecoded || towKnown)
{
SatelliteParameters satelliteParameters = new SatelliteParameters(
measurement.Svid,
new Pseudorange(pseudorangeTOW, 0.0));
satelliteParameters.setUniqueSatId("E" + satelliteParameters.getSatId() + "_E1");
satelliteParameters.setSignalStrength(measurement.Cn0DbHz);
satelliteParameters.setConstellationType(measurement.ConstellationType);
if (measurement.HasCarrierFrequencyHz)
{
satelliteParameters.setCarrierFrequency(measurement.CarrierFrequencyHz);
}
observedSatellites.Add(satelliteParameters);
Log.Debug(TAG, "updateConstellations(" + measurement.Svid + "): " + weekNumber + ", " + tRxGalileoTOW + ", " + pseudorangeTOW);
Log.Debug(TAG, "updateConstellations: Passed with measurement state: " + measState);
}
else if (codeLockE1C)
{
SatelliteParameters satelliteParameters = new SatelliteParameters(
measurement.Svid,
new Pseudorange(pseudorangeE1_2nd, 0.0)
);
satelliteParameters.setUniqueSatId("E" + satelliteParameters.getSatId() + "_E1");
satelliteParameters.setSignalStrength(measurement.Cn0DbHz);
satelliteParameters.setConstellationType(measurement.ConstellationType);
if (measurement.HasCarrierFrequencyHz)
{
satelliteParameters.setCarrierFrequency(measurement.CarrierFrequencyHz);
}
observedSatellites.Add(satelliteParameters);
Log.Debug(TAG, "updateConstellations(" + measurement.Svid + "): " + weekNumber + ", " + tRxGalileoTOW + ", " + pseudorangeE1_2nd);
Log.Debug(TAG, "updateConstellations: Passed with measurement state: " + measState);
}
else
{
SatelliteParameters satelliteParameters = new SatelliteParameters(
measurement.Svid,
null
);
satelliteParameters.setUniqueSatId("E" + satelliteParameters.getSatId() + "_E1");
satelliteParameters.setSignalStrength(measurement.Cn0DbHz);
satelliteParameters.setConstellationType(measurement.ConstellationType);
if (measurement.HasCarrierFrequencyHz)
{
satelliteParameters.setCarrierFrequency(measurement.CarrierFrequencyHz);
}
unusedSatellites.Add(satelliteParameters);
visibleButNotUsed++;
}
}
}
}
override public void updateMeasurements(GnssMeasurementsEvent evento)
{
lock (this) {
visibleButNotUsed = 0;
observedSatellites.Clear();
unusedSatellites.Clear();
GnssClock gnssClock = evento.Clock;
long TimeNanos = gnssClock.TimeNanos;
timeRefMsec = new Time(JavaSystem.CurrentTimeMillis());
double BiasNanos = gnssClock.BiasNanos;
double gpsTime, pseudorange;
// Use only the first instance of the FullBiasNanos (as done in gps-measurement-tools)
if (!fullBiasNanosInitialized)
{
FullBiasNanos = gnssClock.FullBiasNanos;
fullBiasNanosInitialized = true;
}
// Start computing the pseudoranges using the raw data from the phone's GNSS receiver
foreach (GnssMeasurement measurement in evento.Measurements)
{
if (measurement.ConstellationType != constellationId) // si la senial no es de la gps, continue
{
continue;
}
if (measurement.HasCarrierFrequencyHz)
{
if (!approximateEqual(measurement.CarrierFrequencyHz, L1_FREQUENCY, FREQUENCY_MATCH_RANGE))
{
continue;
}
}
// excluding satellites which don't have the L5 component
// if(measurement.getSvid() == 2 || measurement.getSvid() == 4
// || measurement.getSvid() == 5 || measurement.getSvid() == 7
// || measurement.getSvid() == 11 || measurement.getSvid() == 12
// || measurement.getSvid() == 13 || measurement.getSvid() == 14
// || measurement.getSvid() == 15 || measurement.getSvid() == 16
// || measurement.getSvid() == 17 || measurement.getSvid() == 18
// || measurement.getSvid() == 19 || measurement.getSvid() == 20
// || measurement.getSvid() == 21 || measurement.getSvid() == 22
// || measurement.getSvid() == 23 || measurement.getSvid() == 28
// || measurement.getSvid() == 29 || measurement.getSvid() == 31)
// continue;
long ReceivedSvTimeNanos = measurement.ReceivedSvTimeNanos;
double TimeOffsetNanos = measurement.TimeOffsetNanos;
// GPS Time generation (GSA White Paper - page 20)
gpsTime = TimeNanos - (FullBiasNanos + BiasNanos); // TODO intersystem bias?
// Measurement time in full GPS time without taking into account weekNumberNanos(the number of
// nanoseconds that have occurred from the beginning of GPS time to the current
// week number)
tRxGPS =
gpsTime + TimeOffsetNanos;
weekNumberNanos =
System.Math.Floor((-1.0 * FullBiasNanos) / Constants.NUMBER_NANO_SECONDS_PER_WEEK)
* Constants.NUMBER_NANO_SECONDS_PER_WEEK;
// GPS pseudorange computation
pseudorange =
(tRxGPS - weekNumberNanos - ReceivedSvTimeNanos) / 1.0E9
* Constants.SPEED_OF_LIGHT;
// TODO Check that the measurement have a valid state such that valid pseudoranges are used in the PVT algorithm
/*
*
* According to https://developer.android.com/ the GnssMeasurements States required
* for GPS valid pseudoranges are:
*
* int STATE_CODE_LOCK = 1 (1 << 0)
* int int STATE_TOW_DECODED = 8 (1 << 3)
*
*/
GnssState measState = measurement.State;
// Bitwise AND to identify the states
bool codeLock = (measState & GnssState.CodeLock) != GnssState.Unknown;
bool towDecoded = (measState & GnssState.TowDecoded) != 0;
bool towKnown = false;
if (Android.OS.Build.VERSION.SdkInt >= BuildVersionCodes.O)
{
towKnown = (measState & GnssState.TowKnown) != 0;
}
// bool towUncertainty = measurement.getReceivedSvTimeUncertaintyNanos() < MAXTOWUNCNS;
if (codeLock && (towDecoded || towKnown) && pseudorange < 1e9)
{ // && towUncertainty
SatelliteParameters satelliteParameters = new SatelliteParameters(
measurement.Svid,
new Pseudorange(pseudorange, 0.0));
satelliteParameters.setUniqueSatId("G" + satelliteParameters.getSatId() + "_L1");
satelliteParameters.setSignalStrength(measurement.Cn0DbHz);
satelliteParameters.setConstellationType(measurement.ConstellationType);
if (measurement.HasCarrierFrequencyHz)
{
satelliteParameters.setCarrierFrequency(measurement.CarrierFrequencyHz);
}
observedSatellites.Add(satelliteParameters);
//Log.d(TAG, "updateConstellations(" + measurement.Svid + "): " + weekNumberNanos + ", " + tRxGPS + ", " + pseudorange);
//Log.d(TAG, "updateConstellations: Passed with measurement state: " + measState);
}
else
{
SatelliteParameters satelliteParameters = new SatelliteParameters(
measurement.Svid,
null);
satelliteParameters.setUniqueSatId("G" + satelliteParameters.getSatId() + "_L1");
satelliteParameters.setSignalStrength(measurement.Cn0DbHz);
satelliteParameters.setConstellationType(measurement.ConstellationType);
if (measurement.HasCarrierFrequencyHz)
{
satelliteParameters.setCarrierFrequency(measurement.CarrierFrequencyHz);
}
unusedSatellites.Add(satelliteParameters);
visibleButNotUsed++;
}
}
}
}
