#include #include "AP_NavEKF2.h" #include "AP_NavEKF2_core.h" #include #include #include #include extern const AP_HAL::HAL& hal; // Check basic filter health metrics and return a consolidated health status bool NavEKF2_core::healthy(void) const { uint16_t faultInt; getFilterFaults(faultInt); if (faultInt > 0) { return false; } if (velTestRatio > 1 && posTestRatio > 1 && hgtTestRatio > 1) { // all three metrics being above 1 means the filter is // extremely unhealthy. return false; } // Give the filter a second to settle before use if ((imuSampleTime_ms - ekfStartTime_ms) < 1000 ) { return false; } // position and height innovations must be within limits when on-ground and in a static mode of operation float horizErrSq = sq(innovVelPos[3]) + sq(innovVelPos[4]); if (onGround && (PV_AidingMode == AID_NONE) && ((horizErrSq > 1.0f) || (fabsf(hgtInnovFiltState) > 1.0f))) { return false; } // all OK return true; } // Return a consolidated error score where higher numbers represent larger errors // Intended to be used by the front-end to determine which is the primary EKF float NavEKF2_core::errorScore() const { float score = 0.0f; if (tiltAlignComplete && yawAlignComplete) { // Check GPS fusion performance score = MAX(score, 0.5f * (velTestRatio + posTestRatio)); // Check altimeter fusion performance score = MAX(score, hgtTestRatio); // Check attitude corrections const float tiltErrThreshold = 0.05f; score = MAX(score, tiltErrFilt / tiltErrThreshold); } return score; } // return data for debugging optical flow fusion void NavEKF2_core::getFlowDebug(float &varFlow, float &gndOffset, float &flowInnovX, float &flowInnovY, float &auxInnov, float &HAGL, float &rngInnov, float &range, float &gndOffsetErr) const { varFlow = MAX(flowTestRatio[0],flowTestRatio[1]); gndOffset = terrainState; flowInnovX = innovOptFlow[0]; flowInnovY = innovOptFlow[1]; auxInnov = norm(auxFlowObsInnov.x,auxFlowObsInnov.y); HAGL = terrainState - stateStruct.position.z; rngInnov = innovRng; range = rangeDataDelayed.rng; gndOffsetErr = sqrtf(Popt); // note Popt is constrained to be non-negative in EstimateTerrainOffset() } // return data for debugging range beacon fusion one beacon at a time, incrementing the beacon index after each call bool NavEKF2_core::getRangeBeaconDebug(uint8_t &ID, float &rng, float &innov, float &innovVar, float &testRatio, Vector3f &beaconPosNED, float &offsetHigh, float &offsetLow) { // if the states have not been initialised or we have not received any beacon updates then return zeros if (!statesInitialised || N_beacons == 0) { return false; } // Ensure that beacons are not skipped due to calling this function at a rate lower than the updates if (rngBcnFuseDataReportIndex >= N_beacons) { rngBcnFuseDataReportIndex = 0; } // Output the fusion status data for the specified beacon ID = rngBcnFuseDataReportIndex; // beacon identifier rng = rngBcnFusionReport[rngBcnFuseDataReportIndex].rng; // measured range to beacon (m) innov = rngBcnFusionReport[rngBcnFuseDataReportIndex].innov; // range innovation (m) innovVar = rngBcnFusionReport[rngBcnFuseDataReportIndex].innovVar; // innovation variance (m^2) testRatio = rngBcnFusionReport[rngBcnFuseDataReportIndex].testRatio; // innovation consistency test ratio beaconPosNED = rngBcnFusionReport[rngBcnFuseDataReportIndex].beaconPosNED; // beacon NED position offsetHigh = bcnPosOffsetMax; // beacon system vertical pos offset upper estimate offsetLow = bcnPosOffsetMin; // beacon system vertical pos offset lower estimate rngBcnFuseDataReportIndex++; return true; } // provides the height limit to be observed by the control loops // returns false if no height limiting is required // this is needed to ensure the vehicle does not fly too high when using optical flow navigation bool NavEKF2_core::getHeightControlLimit(float &height) const { // only ask for limiting if we are doing optical flow only navigation if (frontend->_fusionModeGPS == 3 && (PV_AidingMode == AID_RELATIVE) && flowDataValid) { // If are doing optical flow nav, ensure the height above ground is within range finder limits after accounting for vehicle tilt and control errors height = MAX(float(frontend->_rng.max_distance_cm_orient(ROTATION_PITCH_270)) * 0.007f - 1.0f, 1.0f); // If we are are not using the range finder as the height reference, then compensate for the difference between terrain and EKF origin if (frontend->_altSource != 1) { height -= terrainState; } return true; } else { return false; } } // return the Euler roll, pitch and yaw angle in radians void NavEKF2_core::getEulerAngles(Vector3f &euler) const { outputDataNew.quat.to_euler(euler.x, euler.y, euler.z); euler = euler - _ahrs->get_trim(); } // return body axis gyro bias estimates in rad/sec void NavEKF2_core::getGyroBias(Vector3f &gyroBias) const { if (dtEkfAvg < 1e-6f) { gyroBias.zero(); return; } gyroBias = stateStruct.gyro_bias / dtEkfAvg; } // return body axis gyro scale factor error as a percentage void NavEKF2_core::getGyroScaleErrorPercentage(Vector3f &gyroScale) const { if (!statesInitialised) { gyroScale.x = gyroScale.y = gyroScale.z = 0; return; } gyroScale.x = 100.0f/stateStruct.gyro_scale.x - 100.0f; gyroScale.y = 100.0f/stateStruct.gyro_scale.y - 100.0f; gyroScale.z = 100.0f/stateStruct.gyro_scale.z - 100.0f; } // return tilt error convergence metric void NavEKF2_core::getTiltError(float &ang) const { ang = tiltErrFilt; } // return the transformation matrix from XYZ (body) to NED axes void NavEKF2_core::getRotationBodyToNED(Matrix3f &mat) const { outputDataNew.quat.rotation_matrix(mat); mat = mat * _ahrs->get_rotation_vehicle_body_to_autopilot_body(); } // return the quaternions defining the rotation from NED to XYZ (body) axes void NavEKF2_core::getQuaternion(Quaternion& ret) const { ret = outputDataNew.quat; } // return the amount of yaw angle change due to the last yaw angle reset in radians // returns the time of the last yaw angle reset or 0 if no reset has ever occurred uint32_t NavEKF2_core::getLastYawResetAngle(float &yawAng) const { yawAng = yawResetAngle; return lastYawReset_ms; } // return the amount of NE position change due to the last position reset in metres // returns the time of the last reset or 0 if no reset has ever occurred uint32_t NavEKF2_core::getLastPosNorthEastReset(Vector2f &pos) const { pos = posResetNE; return lastPosReset_ms; } // return the amount of vertical position change due to the last vertical position reset in metres // returns the time of the last reset or 0 if no reset has ever occurred uint32_t NavEKF2_core::getLastPosDownReset(float &posD) const { posD = posResetD; return lastPosResetD_ms; } // return the amount of NE velocity change due to the last velocity reset in metres/sec // returns the time of the last reset or 0 if no reset has ever occurred uint32_t NavEKF2_core::getLastVelNorthEastReset(Vector2f &vel) const { vel = velResetNE; return lastVelReset_ms; } // return the NED wind speed estimates in m/s (positive is air moving in the direction of the axis) void NavEKF2_core::getWind(Vector3f &wind) const { wind.x = stateStruct.wind_vel.x; wind.y = stateStruct.wind_vel.y; wind.z = 0.0f; // currently don't estimate this } // return the NED velocity of the body frame origin in m/s // void NavEKF2_core::getVelNED(Vector3f &vel) const { // correct for the IMU position offset (EKF calculations are at the IMU) vel = outputDataNew.velocity + velOffsetNED; } // Return the rate of change of vertical position in the down direction (dPosD/dt) of the body frame origin in m/s float NavEKF2_core::getPosDownDerivative(void) const { // return the value calculated from a complementary filter applied to the EKF height and vertical acceleration // correct for the IMU offset (EKF calculations are at the IMU) return vertCompFiltState.vel + velOffsetNED.z; } // This returns the specific forces in the NED frame void NavEKF2_core::getAccelNED(Vector3f &accelNED) const { accelNED = velDotNED; accelNED.z -= GRAVITY_MSS; } // return the Z-accel bias estimate in m/s^2 void NavEKF2_core::getAccelZBias(float &zbias) const { if (dtEkfAvg > 0) { zbias = stateStruct.accel_zbias / dtEkfAvg; } else { zbias = 0; } } // Write the last estimated NE position of the body frame origin relative to the reference point (m). // Return true if the estimate is valid bool NavEKF2_core::getPosNE(Vector2f &posNE) const { // There are three modes of operation, absolute position (GPS fusion), relative position (optical flow fusion) and constant position (no position estimate available) if (PV_AidingMode != AID_NONE) { // This is the normal mode of operation where we can use the EKF position states // correct for the IMU offset (EKF calculations are at the IMU) posNE.x = outputDataNew.position.x + posOffsetNED.x; posNE.y = outputDataNew.position.y + posOffsetNED.y; return true; } else { // In constant position mode the EKF position states are at the origin, so we cannot use them as a position estimate if(validOrigin) { if ((AP::gps().status() >= AP_GPS::GPS_OK_FIX_2D)) { // If the origin has been set and we have GPS, then return the GPS position relative to the origin const struct Location &gpsloc = AP::gps().location(); const Vector2f tempPosNE = EKF_origin.get_distance_NE(gpsloc); posNE.x = tempPosNE.x; posNE.y = tempPosNE.y; return false; } else if (rngBcnAlignmentStarted) { // If we are attempting alignment using range beacon data, then report the position posNE.x = receiverPos.x; posNE.y = receiverPos.y; return false; } else { // If no GPS fix is available, all we can do is provide the last known position posNE.x = outputDataNew.position.x; posNE.y = outputDataNew.position.y; return false; } } else { // If the origin has not been set, then we have no means of providing a relative position posNE.x = 0.0f; posNE.y = 0.0f; return false; } } return false; } // Write the last calculated D position of the body frame origin relative to the EKF origin (m). // Return true if the estimate is valid bool NavEKF2_core::getPosD(float &posD) const { // The EKF always has a height estimate regardless of mode of operation // Correct for the IMU offset in body frame (EKF calculations are at the IMU) // Also correct for changes to the origin height if ((frontend->_originHgtMode & (1<<2)) == 0) { // Any sensor height drift corrections relative to the WGS-84 reference are applied to the origin. posD = outputDataNew.position.z + posOffsetNED.z; } else { // The origin height is static and corrections are applied to the local vertical position // so that height returned by getLLH() = height returned by getOriginLLH - posD posD = outputDataNew.position.z + posOffsetNED.z + 0.01f * (float)EKF_origin.alt - (float)ekfGpsRefHgt; } // Return the current height solution status return filterStatus.flags.vert_pos; } // return the estimated height of body frame origin above ground level bool NavEKF2_core::getHAGL(float &HAGL) const { HAGL = terrainState - outputDataNew.position.z - posOffsetNED.z; // If we know the terrain offset and altitude, then we have a valid height above ground estimate return !hgtTimeout && gndOffsetValid && healthy(); } // Return the last calculated latitude, longitude and height of the body frame origin in WGS-84 // If a calculated location isn't available, return a raw GPS measurement // The status will return true if a calculation or raw measurement is available // The getFilterStatus() function provides a more detailed description of data health and must be checked if data is to be used for flight control bool NavEKF2_core::getLLH(struct Location &loc) const { const AP_GPS &gps = AP::gps(); Location origin; float posD; if(getPosD(posD) && getOriginLLH(origin)) { // Altitude returned is an absolute altitude relative to the WGS-84 spherioid loc.alt = origin.alt - posD*100; loc.relative_alt = 0; loc.terrain_alt = 0; // there are three modes of operation, absolute position (GPS fusion), relative position (optical flow fusion) and constant position (no aiding) if (filterStatus.flags.horiz_pos_abs || filterStatus.flags.horiz_pos_rel) { loc.lat = EKF_origin.lat; loc.lng = EKF_origin.lng; // correct for IMU offset (EKF calculations are at the IMU position) loc.offset((outputDataNew.position.x + posOffsetNED.x), (outputDataNew.position.y + posOffsetNED.y)); return true; } else { // we could be in constant position mode because the vehicle has taken off without GPS, or has lost GPS // in this mode we cannot use the EKF states to estimate position so will return the best available data if ((gps.status() >= AP_GPS::GPS_OK_FIX_2D)) { // we have a GPS position fix to return const struct Location &gpsloc = gps.location(); loc.lat = gpsloc.lat; loc.lng = gpsloc.lng; return true; } else { // if no GPS fix, provide last known position before entering the mode // correct for IMU offset (EKF calculations are at the IMU position) loc.lat = EKF_origin.lat; loc.lng = EKF_origin.lng; loc.offset((lastKnownPositionNE.x + posOffsetNED.x), (lastKnownPositionNE.y + posOffsetNED.y)); return false; } } } else { // If no origin has been defined for the EKF, then we cannot use its position states so return a raw // GPS reading if available and return false if ((gps.status() >= AP_GPS::GPS_OK_FIX_3D)) { const struct Location &gpsloc = gps.location(); loc = gpsloc; loc.relative_alt = 0; loc.terrain_alt = 0; } return false; } } // return the horizontal speed limit in m/s set by optical flow sensor limits // return the scale factor to be applied to navigation velocity gains to compensate for increase in velocity noise with height when using optical flow void NavEKF2_core::getEkfControlLimits(float &ekfGndSpdLimit, float &ekfNavVelGainScaler) const { if (PV_AidingMode == AID_RELATIVE) { // allow 1.0 rad/sec margin for angular motion ekfGndSpdLimit = MAX((frontend->_maxFlowRate - 1.0f), 0.0f) * MAX((terrainState - stateStruct.position[2]), rngOnGnd); // use standard gains up to 5.0 metres height and reduce above that ekfNavVelGainScaler = 4.0f / MAX((terrainState - stateStruct.position[2]),4.0f); } else { ekfGndSpdLimit = 400.0f; //return 80% of max filter speed ekfNavVelGainScaler = 1.0f; } } // return the LLH location of the filters NED origin bool NavEKF2_core::getOriginLLH(struct Location &loc) const { if (validOrigin) { loc = EKF_origin; // report internally corrected reference height if enabled if ((frontend->_originHgtMode & (1<<2)) == 0) { loc.alt = (int32_t)(100.0f * (float)ekfGpsRefHgt); } } return validOrigin; } // return earth magnetic field estimates in measurement units / 1000 void NavEKF2_core::getMagNED(Vector3f &magNED) const { magNED = stateStruct.earth_magfield * 1000.0f; } // return body magnetic field estimates in measurement units / 1000 void NavEKF2_core::getMagXYZ(Vector3f &magXYZ) const { magXYZ = stateStruct.body_magfield*1000.0f; } // return magnetometer offsets // return true if offsets are valid bool NavEKF2_core::getMagOffsets(uint8_t mag_idx, Vector3f &magOffsets) const { if (!_ahrs->get_compass()) { return false; } // compass offsets are valid if we have finalised magnetic field initialisation, magnetic field learning is not prohibited, // primary compass is valid and state variances have converged const float maxMagVar = 5E-6f; bool variancesConverged = (P[19][19] < maxMagVar) && (P[20][20] < maxMagVar) && (P[21][21] < maxMagVar); if ((mag_idx == magSelectIndex) && finalInflightMagInit && !inhibitMagStates && _ahrs->get_compass()->healthy(magSelectIndex) && variancesConverged) { magOffsets = _ahrs->get_compass()->get_offsets(magSelectIndex) - stateStruct.body_magfield*1000.0f; return true; } else { magOffsets = _ahrs->get_compass()->get_offsets(magSelectIndex); return false; } } // return the index for the active magnetometer uint8_t NavEKF2_core::getActiveMag() const { return (uint8_t)magSelectIndex; } // return the innovations for the NED Pos, NED Vel, XYZ Mag and Vtas measurements void NavEKF2_core::getInnovations(Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const { velInnov.x = innovVelPos[0]; velInnov.y = innovVelPos[1]; velInnov.z = innovVelPos[2]; posInnov.x = innovVelPos[3]; posInnov.y = innovVelPos[4]; posInnov.z = innovVelPos[5]; magInnov.x = 1e3f*innovMag[0]; // Convert back to sensor units magInnov.y = 1e3f*innovMag[1]; // Convert back to sensor units magInnov.z = 1e3f*innovMag[2]; // Convert back to sensor units tasInnov = innovVtas; yawInnov = innovYaw; } // return the innovation consistency test ratios for the velocity, position, magnetometer and true airspeed measurements // this indicates the amount of margin available when tuning the various error traps // also return the delta in position due to the last position reset void NavEKF2_core::getVariances(float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const { velVar = sqrtf(velTestRatio); posVar = sqrtf(posTestRatio); hgtVar = sqrtf(hgtTestRatio); // If we are using simple compass yaw fusion, populate all three components with the yaw test ratio to provide an equivalent output magVar.x = sqrtf(MAX(magTestRatio.x,yawTestRatio)); magVar.y = sqrtf(MAX(magTestRatio.y,yawTestRatio)); magVar.z = sqrtf(MAX(magTestRatio.z,yawTestRatio)); tasVar = sqrtf(tasTestRatio); offset = posResetNE; } /* return the filter fault status as a bitmasked integer 0 = quaternions are NaN 1 = velocities are NaN 2 = badly conditioned X magnetometer fusion 3 = badly conditioned Y magnetometer fusion 5 = badly conditioned Z magnetometer fusion 6 = badly conditioned airspeed fusion 7 = badly conditioned synthetic sideslip fusion 7 = filter is not initialised */ void NavEKF2_core::getFilterFaults(uint16_t &faults) const { faults = (stateStruct.quat.is_nan()<<0 | stateStruct.velocity.is_nan()<<1 | faultStatus.bad_xmag<<2 | faultStatus.bad_ymag<<3 | faultStatus.bad_zmag<<4 | faultStatus.bad_airspeed<<5 | faultStatus.bad_sideslip<<6 | !statesInitialised<<7); } /* return filter timeout status as a bitmasked integer 0 = position measurement timeout 1 = velocity measurement timeout 2 = height measurement timeout 3 = magnetometer measurement timeout 4 = true airspeed measurement timeout 5 = unassigned 6 = unassigned 7 = unassigned */ void NavEKF2_core::getFilterTimeouts(uint8_t &timeouts) const { timeouts = (posTimeout<<0 | velTimeout<<1 | hgtTimeout<<2 | magTimeout<<3 | tasTimeout<<4); } // Return the navigation filter status message void NavEKF2_core::getFilterStatus(nav_filter_status &status) const { status = filterStatus; } /* return filter gps quality check status */ void NavEKF2_core::getFilterGpsStatus(nav_gps_status &faults) const { // init return value faults.value = 0; // set individual flags faults.flags.bad_sAcc = gpsCheckStatus.bad_sAcc; // reported speed accuracy is insufficient faults.flags.bad_hAcc = gpsCheckStatus.bad_hAcc; // reported horizontal position accuracy is insufficient faults.flags.bad_vAcc = gpsCheckStatus.bad_vAcc; // reported vertical position accuracy is insufficient faults.flags.bad_yaw = gpsCheckStatus.bad_yaw; // EKF heading accuracy is too large for GPS use faults.flags.bad_sats = gpsCheckStatus.bad_sats; // reported number of satellites is insufficient 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 faults.flags.bad_horiz_vel = gpsCheckStatus.bad_horiz_vel; // The GPS horizontal speed is excessive (check assumes the vehicle is static) } // send an EKF_STATUS message to GCS void NavEKF2_core::send_status_report(mavlink_channel_t chan) { // prepare flags uint16_t flags = 0; if (filterStatus.flags.attitude) { flags |= EKF_ATTITUDE; } if (filterStatus.flags.horiz_vel) { flags |= EKF_VELOCITY_HORIZ; } if (filterStatus.flags.vert_vel) { flags |= EKF_VELOCITY_VERT; } if (filterStatus.flags.horiz_pos_rel) { flags |= EKF_POS_HORIZ_REL; } if (filterStatus.flags.horiz_pos_abs) { flags |= EKF_POS_HORIZ_ABS; } if (filterStatus.flags.vert_pos) { flags |= EKF_POS_VERT_ABS; } if (filterStatus.flags.terrain_alt) { flags |= EKF_POS_VERT_AGL; } if (filterStatus.flags.const_pos_mode) { flags |= EKF_CONST_POS_MODE; } if (filterStatus.flags.pred_horiz_pos_rel) { flags |= EKF_PRED_POS_HORIZ_REL; } if (filterStatus.flags.pred_horiz_pos_abs) { flags |= EKF_PRED_POS_HORIZ_ABS; } // get variances float velVar, posVar, hgtVar, tasVar; Vector3f magVar; Vector2f offset; getVariances(velVar, posVar, hgtVar, magVar, tasVar, offset); const float mag_max = fmaxf(fmaxf(magVar.x,magVar.y),magVar.z); // Only report range finder normalised innovation levels if the EKF needs the data for primary // height estimation or optical flow operation. This prevents false alarms at the GCS if a // range finder is fitted for other applications float temp; if (((frontend->_useRngSwHgt > 0) && activeHgtSource == HGT_SOURCE_RNG) || (PV_AidingMode == AID_RELATIVE && flowDataValid)) { temp = sqrtf(auxRngTestRatio); } else { temp = 0.0f; } // send message mavlink_msg_ekf_status_report_send(chan, flags, velVar, posVar, hgtVar, mag_max, temp, tasVar); } // report the reason for why the backend is refusing to initialise const char *NavEKF2_core::prearm_failure_reason(void) const { if (gpsGoodToAlign) { // we are not failing return nullptr; } return prearm_fail_string; } // report the number of frames lapsed since the last state prediction // this is used by other instances to level load uint8_t NavEKF2_core::getFramesSincePredict(void) const { return framesSincePredict; } // publish output observer angular, velocity and position tracking error void NavEKF2_core::getOutputTrackingError(Vector3f &error) const { error = outputTrackError; } // return true when external nav data is also being used as a yaw observation bool NavEKF2_core::isExtNavUsedForYaw() { return extNavUsedForYaw; }