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AP_NavEKF: Add fix status to GPS check report message

This commit is contained in:
Paul Riseborough 2015-10-08 16:16:53 -07:00 committed by Randy Mackay
parent ba6387f206
commit ef5049862a
3 changed files with 82 additions and 72 deletions
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152
libraries/AP_NavEKF/AP_NavEKF.cpp
View File

@ -4234,88 +4234,95 @@ void NavEKF::readIMUData()
void NavEKF::readGpsData()
{
// check for new GPS data
if ((_ahrs->get_gps().last_message_time_ms() != lastFixTime_ms) &&
(_ahrs->get_gps().status() >= AP_GPS::GPS_OK_FIX_3D))
{
// store fix time from previous read
secondLastFixTime_ms = lastFixTime_ms;
if (_ahrs->get_gps().last_message_time_ms() != lastFixTime_ms) {
if (_ahrs->get_gps().status() >= AP_GPS::GPS_OK_FIX_3D) {
// report GPS fix status
gpsCheckStatus.bad_fix = false;
// get current fix time
lastFixTime_ms = _ahrs->get_gps().last_message_time_ms();
// store fix time from previous read
secondLastFixTime_ms = lastFixTime_ms;
// set flag that lets other functions know that new GPS data has arrived
newDataGps = true;
// get current fix time
lastFixTime_ms = _ahrs->get_gps().last_message_time_ms();
// get state vectors that were stored at the time that is closest to when the the GPS measurement
// time after accounting for measurement delays
RecallStates(statesAtVelTime, (imuSampleTime_ms - constrain_int16(_msecVelDelay, 0, 500)));
RecallStates(statesAtPosTime, (imuSampleTime_ms - constrain_int16(_msecPosDelay, 0, 500)));
// set flag that lets other functions know that new GPS data has arrived
newDataGps = true;
// read the NED velocity from the GPS
velNED = _ahrs->get_gps().velocity();
// get state vectors that were stored at the time that is closest to when the the GPS measurement
// time after accounting for measurement delays
RecallStates(statesAtVelTime, (imuSampleTime_ms - constrain_int16(_msecVelDelay, 0, 500)));
RecallStates(statesAtPosTime, (imuSampleTime_ms - constrain_int16(_msecPosDelay, 0, 500)));
// Use the speed accuracy from the GPS if available, otherwise set it to zero.
// Apply a decaying envelope filter with a 5 second time constant to the raw speed accuracy data
float alpha = constrain_float(0.0002f * (lastFixTime_ms - secondLastFixTime_ms),0.0f,1.0f);
gpsSpdAccuracy *= (1.0f - alpha);
float gpsSpdAccRaw;
if (!_ahrs->get_gps().speed_accuracy(gpsSpdAccRaw)) {
gpsSpdAccuracy = 0.0f;
} else {
gpsSpdAccuracy = max(gpsSpdAccuracy,gpsSpdAccRaw);
}
// read the NED velocity from the GPS
velNED = _ahrs->get_gps().velocity();
// check if we have enough GPS satellites and increase the gps noise scaler if we don't
if (_ahrs->get_gps().num_sats() >= 6 && !constPosMode) {
gpsNoiseScaler = 1.0f;
} else if (_ahrs->get_gps().num_sats() == 5 && !constPosMode) {
gpsNoiseScaler = 1.4f;
} else { // <= 4 satellites or in constant position mode
gpsNoiseScaler = 2.0f;
}
// Check if GPS can output vertical velocity and set GPS fusion mode accordingly
if (_ahrs->get_gps().have_vertical_velocity() && _fusionModeGPS == 0) {
useGpsVertVel = true;
} else {
useGpsVertVel = false;
}
// Monitor quality of the GPS velocity data for alignment
gpsGoodToAlign = calcGpsGoodToAlign();
// Monitor qulaity of GPS data inflight
calcGpsGoodForFlight();
// read latitutde and longitude from GPS and convert to local NE position relative to the stored origin
// If we don't have an origin, then set it to the current GPS coordinates
const struct Location &gpsloc = _ahrs->get_gps().location();
if (validOrigin) {
gpsPosNE = location_diff(EKF_origin, gpsloc);
} else if (gpsGoodToAlign){
// Set the NE origin to the current GPS position
setOrigin();
// Now we know the location we have an estimate for the magnetic field declination and adjust the earth field accordingly
alignMagStateDeclination();
// Set the height of the NED origin to ‘height of baro height datum relative to GPS height datum'
EKF_origin.alt = gpsloc.alt - hgtMea;
// We are by definition at the origin at the instant of alignment so set NE position to zero
gpsPosNE.zero();
// If the vehicle is in flight (use arm status to determine) and GPS useage isn't explicitly prohibited, we switch to absolute position mode
if (vehicleArmed && _fusionModeGPS != 3) {
constPosMode = false;
PV_AidingMode = AID_ABSOLUTE;
gpsNotAvailable = false;
// Initialise EKF position and velocity states
ResetPosition();
ResetVelocity();
// Use the speed accuracy from the GPS if available, otherwise set it to zero.
// Apply a decaying envelope filter with a 5 second time constant to the raw speed accuracy data
float alpha = constrain_float(0.0002f * (lastFixTime_ms - secondLastFixTime_ms),0.0f,1.0f);
gpsSpdAccuracy *= (1.0f - alpha);
float gpsSpdAccRaw;
if (!_ahrs->get_gps().speed_accuracy(gpsSpdAccRaw)) {
gpsSpdAccuracy = 0.0f;
} else {
gpsSpdAccuracy = max(gpsSpdAccuracy,gpsSpdAccRaw);
}
}
// calculate a position offset which is applied to NE position and velocity wherever it is used throughout code to allow GPS position jumps to be accommodated gradually
decayGpsOffset();
// check if we have enough GPS satellites and increase the gps noise scaler if we don't
if (_ahrs->get_gps().num_sats() >= 6 && !constPosMode) {
gpsNoiseScaler = 1.0f;
} else if (_ahrs->get_gps().num_sats() == 5 && !constPosMode) {
gpsNoiseScaler = 1.4f;
} else { // <= 4 satellites or in constant position mode
gpsNoiseScaler = 2.0f;
}
// Check if GPS can output vertical velocity and set GPS fusion mode accordingly
if (_ahrs->get_gps().have_vertical_velocity() && _fusionModeGPS == 0) {
useGpsVertVel = true;
} else {
useGpsVertVel = false;
}
// Monitor quality of the GPS velocity data for alignment
gpsGoodToAlign = calcGpsGoodToAlign();
// Monitor qulaity of GPS data inflight
calcGpsGoodForFlight();
// read latitutde and longitude from GPS and convert to local NE position relative to the stored origin
// If we don't have an origin, then set it to the current GPS coordinates
const struct Location &gpsloc = _ahrs->get_gps().location();
if (validOrigin) {
gpsPosNE = location_diff(EKF_origin, gpsloc);
} else if (gpsGoodToAlign){
// Set the NE origin to the current GPS position
setOrigin();
// Now we know the location we have an estimate for the magnetic field declination and adjust the earth field accordingly
alignMagStateDeclination();
// Set the height of the NED origin to ‘height of baro height datum relative to GPS height datum'
EKF_origin.alt = gpsloc.alt - hgtMea;
// We are by definition at the origin at the instant of alignment so set NE position to zero
gpsPosNE.zero();
// If the vehicle is in flight (use arm status to determine) and GPS useage isn't explicitly prohibited, we switch to absolute position mode
if (vehicleArmed && _fusionModeGPS != 3) {
constPosMode = false;
PV_AidingMode = AID_ABSOLUTE;
gpsNotAvailable = false;
// Initialise EKF position and velocity states
ResetPosition();
ResetVelocity();
}
}
// calculate a position offset which is applied to NE position and velocity wherever it is used throughout code to allow GPS position jumps to be accommodated gradually
decayGpsOffset();
} else {
// report GPS fix status
gpsCheckStatus.bad_fix = true;
}
}
// If no previous GPS lock or told not to use it, or EKF origin not set, we declare the GPS unavailable for use
if ((_ahrs->get_gps().status() < AP_GPS::GPS_OK_FIX_3D) || _fusionModeGPS == 3 || !validOrigin) {
gpsNotAvailable = true;
@ -4951,6 +4958,7 @@ void NavEKF::getFilterGpsStatus(nav_gps_status &faults) const
faults.flags.bad_horiz_drift = gpsCheckStatus.bad_horiz_drift; // GPS horizontal drift is too large to start using GPS (check assumes vehicle is static)
faults.flags.bad_hdop = gpsCheckStatus.bad_hdop; // reported HDoP is too large to start using GPS
faults.flags.bad_vert_vel = gpsCheckStatus.bad_vert_vel; // GPS vertical speed is too large to start using GPS (check assumes vehicle is static)
faults.flags.bad_fix = gpsCheckStatus.bad_fix; // The GPS cannot provide the 3D fix required
}
/*

1
libraries/AP_NavEKF/AP_NavEKF.h
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@ -846,6 +846,7 @@ private:
bool bad_horiz_drift:1;
bool bad_hdop:1;
bool bad_vert_vel:1;
bool bad_fix:1;
} gpsCheckStatus;
// states held by magnetomter fusion across time steps

1
libraries/AP_NavEKF/AP_Nav_Common.h
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@ -50,6 +50,7 @@ union nav_gps_status {
uint16_t bad_horiz_drift : 1; // 5 - true if the GPS horizontal position is drifting (this check assumes vehicle is static)
uint16_t bad_hdop : 1; // 6 - true if the reported HDoP is insufficient to start using GPS
uint16_t bad_vert_vel : 1; // 7 - true if the GPS vertical speed is too large to start using GPS (this check assumes vehicle is static)
uint16_t bad_fix : 1; // 8 - true if the GPS is not providing a 3D fix
} flags;
uint16_t value;
};