mirror of https://github.com/ArduPilot/ardupilot
431 lines
20 KiB
C++
431 lines
20 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
|
|
|
|
#include <AP_HAL/AP_HAL.h>
|
|
|
|
#if HAL_CPU_CLASS >= HAL_CPU_CLASS_150
|
|
|
|
#include "AP_NavEKF2.h"
|
|
#include "AP_NavEKF2_core.h"
|
|
#include <AP_AHRS/AP_AHRS.h>
|
|
#include <AP_Vehicle/AP_Vehicle.h>
|
|
#include <GCS_MAVLink/GCS.h>
|
|
|
|
#include <stdio.h>
|
|
|
|
extern const AP_HAL::HAL& hal;
|
|
|
|
|
|
// Control filter mode transitions
|
|
void NavEKF2_core::controlFilterModes()
|
|
{
|
|
// Determine motor arm status
|
|
prevMotorsArmed = motorsArmed;
|
|
motorsArmed = hal.util->get_soft_armed();
|
|
if (motorsArmed && !prevMotorsArmed) {
|
|
// set the time at which we arm to assist with checks
|
|
timeAtArming_ms = imuSampleTime_ms;
|
|
}
|
|
|
|
// Detect if we are in flight on or ground
|
|
detectFlight();
|
|
|
|
// Determine if learning of wind and magnetic field will be enabled and set corresponding indexing limits to
|
|
// avoid unnecessary operations
|
|
setWindMagStateLearningMode();
|
|
|
|
// Check the alignmnent status of the tilt and yaw attitude
|
|
// Used during initial bootstrap alignment of the filter
|
|
checkAttitudeAlignmentStatus();
|
|
|
|
// Set the type of inertial navigation aiding used
|
|
setAidingMode();
|
|
|
|
}
|
|
|
|
/*
|
|
return effective value for _magCal for this core
|
|
*/
|
|
uint8_t NavEKF2_core::effective_magCal(void) const
|
|
{
|
|
// if we are on the 2nd core and _magCal is 3 then treat it as
|
|
// 2. This is a workaround for a mag fusion problem
|
|
if (frontend->_magCal ==3 && imu_index == 1) {
|
|
return 2;
|
|
}
|
|
return frontend->_magCal;
|
|
}
|
|
|
|
// Determine if learning of wind and magnetic field will be enabled and set corresponding indexing limits to
|
|
// avoid unnecessary operations
|
|
void NavEKF2_core::setWindMagStateLearningMode()
|
|
{
|
|
// If we are on ground, or in constant position mode, or don't have the right vehicle and sensing to estimate wind, inhibit wind states
|
|
bool setWindInhibit = (!useAirspeed() && !assume_zero_sideslip()) || onGround || (PV_AidingMode == AID_NONE);
|
|
if (!inhibitWindStates && setWindInhibit) {
|
|
inhibitWindStates = true;
|
|
} else if (inhibitWindStates && !setWindInhibit) {
|
|
inhibitWindStates = false;
|
|
// set states and variances
|
|
if (yawAlignComplete && useAirspeed()) {
|
|
// if we have airspeed and a valid heading, set the wind states to the reciprocal of the vehicle heading
|
|
// which assumes the vehicle has launched into the wind
|
|
Vector3f tempEuler;
|
|
stateStruct.quat.to_euler(tempEuler.x, tempEuler.y, tempEuler.z);
|
|
float windSpeed = sqrtf(sq(stateStruct.velocity.x) + sq(stateStruct.velocity.y)) - tasDataDelayed.tas;
|
|
stateStruct.wind_vel.x = windSpeed * cosf(tempEuler.z);
|
|
stateStruct.wind_vel.y = windSpeed * sinf(tempEuler.z);
|
|
|
|
// set the wind sate variances to the measurement uncertainty
|
|
for (uint8_t index=22; index<=23; index++) {
|
|
P[index][index] = sq(constrain_float(frontend->_easNoise, 0.5f, 5.0f) * constrain_float(_ahrs->get_EAS2TAS(), 0.9f, 10.0f));
|
|
}
|
|
} else {
|
|
// set the variances using a typical wind speed
|
|
for (uint8_t index=22; index<=23; index++) {
|
|
P[index][index] = sq(5.0f);
|
|
}
|
|
}
|
|
}
|
|
|
|
// determine if the vehicle is manoevring
|
|
if (accNavMagHoriz > 0.5f) {
|
|
manoeuvring = true;
|
|
} else {
|
|
manoeuvring = false;
|
|
}
|
|
|
|
// Determine if learning of magnetic field states has been requested by the user
|
|
uint8_t magCal = effective_magCal();
|
|
bool magCalRequested =
|
|
((magCal == 0) && inFlight) || // when flying
|
|
((magCal == 1) && manoeuvring) || // when manoeuvring
|
|
((magCal == 3) && finalInflightYawInit && finalInflightMagInit) || // when initial in-air yaw and mag field reset is complete
|
|
(magCal == 4); // all the time
|
|
|
|
// Deny mag calibration request if we aren't using the compass, it has been inhibited by the user,
|
|
// we do not have an absolute position reference or are on the ground (unless explicitly requested by the user)
|
|
bool magCalDenied = !use_compass() || (magCal == 2) || (onGround && magCal != 4);
|
|
|
|
// Inhibit the magnetic field calibration if not requested or denied
|
|
bool setMagInhibit = !magCalRequested || magCalDenied;
|
|
if (!inhibitMagStates && setMagInhibit) {
|
|
inhibitMagStates = true;
|
|
} else if (inhibitMagStates && !setMagInhibit) {
|
|
inhibitMagStates = false;
|
|
if (magFieldLearned) {
|
|
// if we have already learned the field states, then retain the learned variances
|
|
P[16][16] = earthMagFieldVar.x;
|
|
P[17][17] = earthMagFieldVar.y;
|
|
P[18][18] = earthMagFieldVar.z;
|
|
P[19][19] = bodyMagFieldVar.x;
|
|
P[20][20] = bodyMagFieldVar.y;
|
|
P[21][21] = bodyMagFieldVar.z;
|
|
} else {
|
|
// set the variances equal to the observation variances
|
|
for (uint8_t index=18; index<=21; index++) {
|
|
P[index][index] = sq(frontend->_magNoise);
|
|
}
|
|
|
|
// set the NE earth magnetic field states using the published declination
|
|
// and set the corresponding variances and covariances
|
|
alignMagStateDeclination();
|
|
|
|
}
|
|
// request a reset of the yaw and magnetic field states if not done before
|
|
if (!magStateInitComplete || (!finalInflightMagInit && inFlight)) {
|
|
magYawResetRequest = true;
|
|
}
|
|
}
|
|
|
|
// If on ground we clear the flag indicating that the magnetic field in-flight initialisation has been completed
|
|
// because we want it re-done for each takeoff
|
|
if (onGround) {
|
|
finalInflightYawInit = false;
|
|
finalInflightMagInit = false;
|
|
}
|
|
|
|
// Adjust the indexing limits used to address the covariance, states and other EKF arrays to avoid unnecessary operations
|
|
// if we are not using those states
|
|
if (inhibitMagStates && inhibitWindStates) {
|
|
stateIndexLim = 15;
|
|
} else if (inhibitWindStates) {
|
|
stateIndexLim = 21;
|
|
} else {
|
|
stateIndexLim = 23;
|
|
}
|
|
}
|
|
|
|
// Set inertial navigation aiding mode
|
|
void NavEKF2_core::setAidingMode()
|
|
{
|
|
// Save the previous status so we can detect when it has changed
|
|
PV_AidingModePrev = PV_AidingMode;
|
|
|
|
// Determine if we should change aiding mode
|
|
if (PV_AidingMode == AID_NONE) {
|
|
// Don't allow filter to start position or velocity aiding until the tilt and yaw alignment is complete
|
|
// and IMU gyro bias estimates have stabilised
|
|
bool filterIsStable = tiltAlignComplete && yawAlignComplete && checkGyroCalStatus();
|
|
// If GPS usage has been prohiited then we use flow aiding provided optical flow data is present
|
|
// GPS aiding is the perferred option unless excluded by the user
|
|
if((frontend->_fusionModeGPS) != 3 && readyToUseGPS() && filterIsStable && !gpsInhibit) {
|
|
PV_AidingMode = AID_ABSOLUTE;
|
|
} else if ((frontend->_fusionModeGPS == 3) && optFlowDataPresent()) {
|
|
PV_AidingMode = AID_RELATIVE;
|
|
}
|
|
} else if (PV_AidingMode == AID_RELATIVE) {
|
|
// Check if the optical flow sensor has timed out
|
|
bool flowSensorTimeout = ((imuSampleTime_ms - flowValidMeaTime_ms) > 5000);
|
|
// Check if the fusion has timed out (flow measurements have been rejected for too long)
|
|
bool flowFusionTimeout = ((imuSampleTime_ms - prevFlowFuseTime_ms) > 5000);
|
|
if (flowSensorTimeout || flowFusionTimeout) {
|
|
PV_AidingMode = AID_NONE;
|
|
}
|
|
} else if (PV_AidingMode == AID_ABSOLUTE) {
|
|
// check if we can use opticalflow as a backup
|
|
bool optFlowBackupAvailable = (flowDataValid && !hgtTimeout);
|
|
|
|
// Set GPS time-out threshold depending on whether we have an airspeed sensor to constrain drift
|
|
uint16_t gpsRetryTimeout_ms = useAirspeed() ? frontend->gpsRetryTimeUseTAS_ms : frontend->gpsRetryTimeNoTAS_ms;
|
|
|
|
// Set the time that copters will fly without a GPS lock before failing the GPS and switching to a non GPS mode
|
|
uint16_t gpsFailTimeout_ms = optFlowBackupAvailable ? frontend->gpsFailTimeWithFlow_ms : gpsRetryTimeout_ms;
|
|
|
|
// If we haven't received GPS data for a while and we are using it for aiding, then declare the position and velocity data as being timed out
|
|
if (imuSampleTime_ms - lastTimeGpsReceived_ms > gpsFailTimeout_ms) {
|
|
|
|
// Let other processes know that GPS is not available and that a timeout has occurred
|
|
posTimeout = true;
|
|
velTimeout = true;
|
|
gpsNotAvailable = true;
|
|
|
|
// If we are totally reliant on GPS for navigation, then we need to switch to a non-GPS mode of operation
|
|
// If we don't have airspeed or sideslip assumption or optical flow to constrain drift, then go into constant position mode.
|
|
// If we can do optical flow nav (valid flow data and height above ground estimate), then go into flow nav mode.
|
|
if (!useAirspeed() && !assume_zero_sideslip()) {
|
|
if (optFlowBackupAvailable) {
|
|
// attempt optical flow navigation
|
|
PV_AidingMode = AID_RELATIVE;
|
|
} else {
|
|
// put the filter into constant position mode
|
|
PV_AidingMode = AID_NONE;
|
|
}
|
|
}
|
|
} else if (gpsInhibit) {
|
|
// put the filter into constant position mode in response to an exernal request
|
|
PV_AidingMode = AID_NONE;
|
|
}
|
|
}
|
|
|
|
// check to see if we are starting or stopping aiding and set states and modes as required
|
|
if (PV_AidingMode != PV_AidingModePrev) {
|
|
// set various usage modes based on the condition when we start aiding. These are then held until aiding is stopped.
|
|
if (PV_AidingMode == AID_NONE) {
|
|
// We have ceased aiding
|
|
GCS_MAVLINK::send_statustext_all(MAV_SEVERITY_WARNING, "EKF2 IMU%u has stopped aiding",(unsigned)imu_index);
|
|
// When not aiding, estimate orientation & height fusing synthetic constant position and zero velocity measurement to constrain tilt errors
|
|
posTimeout = true;
|
|
velTimeout = true;
|
|
// Reset the normalised innovation to avoid false failing bad fusion tests
|
|
velTestRatio = 0.0f;
|
|
posTestRatio = 0.0f;
|
|
// store the current position to be used to keep reporting the last known position
|
|
lastKnownPositionNE.x = stateStruct.position.x;
|
|
lastKnownPositionNE.y = stateStruct.position.y;
|
|
// initialise filtered altitude used to provide a takeoff reference to current baro on disarm
|
|
// this reduces the time required for the baro noise filter to settle before the filtered baro data can be used
|
|
meaHgtAtTakeOff = baroDataDelayed.hgt;
|
|
// reset the vertical position state to faster recover from baro errors experienced during touchdown
|
|
stateStruct.position.z = -meaHgtAtTakeOff;
|
|
} else if (PV_AidingMode == AID_RELATIVE) {
|
|
// We have commenced aiding, but GPS usage has been prohibited so use optical flow only
|
|
GCS_MAVLINK::send_statustext_all(MAV_SEVERITY_WARNING, "EKF2 IMU%u is using optical flow",(unsigned)imu_index);
|
|
posTimeout = true;
|
|
velTimeout = true;
|
|
// Reset the last valid flow measurement time
|
|
flowValidMeaTime_ms = imuSampleTime_ms;
|
|
// Reset the last valid flow fusion time
|
|
prevFlowFuseTime_ms = imuSampleTime_ms;
|
|
} else if (PV_AidingMode == AID_ABSOLUTE) {
|
|
// We have commenced aiding and GPS usage is allowed
|
|
GCS_MAVLINK::send_statustext_all(MAV_SEVERITY_WARNING, "EKF2 IMU%u is using GPS",(unsigned)imu_index);
|
|
posTimeout = false;
|
|
velTimeout = false;
|
|
// we need to reset the GPS timers to prevent GPS timeout logic being invoked on entry into GPS aiding
|
|
// this is because the EKF can be interrupted for an arbitrary amount of time during vehicle arming checks
|
|
lastTimeGpsReceived_ms = imuSampleTime_ms;
|
|
secondLastGpsTime_ms = imuSampleTime_ms;
|
|
// reset the last valid position fix time to prevent unwanted activation of GPS glitch logic
|
|
lastPosPassTime_ms = imuSampleTime_ms;
|
|
}
|
|
|
|
// Always reset the position and velocity when changing mode
|
|
ResetVelocity();
|
|
ResetPosition();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// Check the tilt and yaw alignmnent status
|
|
// Used during initial bootstrap alignment of the filter
|
|
void NavEKF2_core::checkAttitudeAlignmentStatus()
|
|
{
|
|
// Check for tilt convergence - used during initial alignment
|
|
float alpha = 1.0f*imuDataDelayed.delAngDT;
|
|
float temp=tiltErrVec.length();
|
|
tiltErrFilt = alpha*temp + (1.0f-alpha)*tiltErrFilt;
|
|
if (tiltErrFilt < 0.005f && !tiltAlignComplete) {
|
|
tiltAlignComplete = true;
|
|
GCS_MAVLINK::send_statustext_all(MAV_SEVERITY_WARNING, "EKF2 IMU%u tilt alignment complete",(unsigned)imu_index);
|
|
}
|
|
|
|
// submit yaw and magnetic field reset requests depending on whether we have compass data
|
|
if (tiltAlignComplete && !yawAlignComplete) {
|
|
if (use_compass()) {
|
|
magYawResetRequest = true;
|
|
gpsYawResetRequest = false;
|
|
} else {
|
|
magYawResetRequest = false;
|
|
gpsYawResetRequest = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
// return true if we should use the airspeed sensor
|
|
bool NavEKF2_core::useAirspeed(void) const
|
|
{
|
|
return _ahrs->airspeed_sensor_enabled();
|
|
}
|
|
|
|
// return true if we should use the range finder sensor
|
|
bool NavEKF2_core::useRngFinder(void) const
|
|
{
|
|
// TO-DO add code to set this based in setting of optical flow use parameter and presence of sensor
|
|
return true;
|
|
}
|
|
|
|
// return true if optical flow data is available
|
|
bool NavEKF2_core::optFlowDataPresent(void) const
|
|
{
|
|
return (imuSampleTime_ms - flowMeaTime_ms < 200);
|
|
}
|
|
|
|
// return true if the filter to be ready to use gps
|
|
bool NavEKF2_core::readyToUseGPS(void) const
|
|
{
|
|
return validOrigin && tiltAlignComplete && yawAlignComplete && gpsGoodToAlign && (frontend->_fusionModeGPS != 3) && gpsDataToFuse;
|
|
}
|
|
|
|
// return true if we should use the compass
|
|
bool NavEKF2_core::use_compass(void) const
|
|
{
|
|
return _ahrs->get_compass() && _ahrs->get_compass()->use_for_yaw(magSelectIndex) && !allMagSensorsFailed;
|
|
}
|
|
|
|
/*
|
|
should we assume zero sideslip?
|
|
*/
|
|
bool NavEKF2_core::assume_zero_sideslip(void) const
|
|
{
|
|
// we don't assume zero sideslip for ground vehicles as EKF could
|
|
// be quite sensitive to a rapid spin of the ground vehicle if
|
|
// traction is lost
|
|
return _ahrs->get_fly_forward() && _ahrs->get_vehicle_class() != AHRS_VEHICLE_GROUND;
|
|
}
|
|
|
|
// set the LLH location of the filters NED origin
|
|
bool NavEKF2_core::setOriginLLH(struct Location &loc)
|
|
{
|
|
if (PV_AidingMode == AID_ABSOLUTE) {
|
|
return false;
|
|
}
|
|
EKF_origin = loc;
|
|
validOrigin = true;
|
|
return true;
|
|
}
|
|
|
|
// Set the NED origin to be used until the next filter reset
|
|
void NavEKF2_core::setOrigin()
|
|
{
|
|
// assume origin at current GPS location (no averaging)
|
|
EKF_origin = _ahrs->get_gps().location();
|
|
// define Earth rotation vector in the NED navigation frame at the origin
|
|
calcEarthRateNED(earthRateNED, _ahrs->get_home().lat);
|
|
validOrigin = true;
|
|
GCS_MAVLINK::send_statustext_all(MAV_SEVERITY_WARNING, "EKF2 IMU%u Origin Set",(unsigned)imu_index);
|
|
}
|
|
|
|
// record a yaw reset event
|
|
void NavEKF2_core::recordYawReset()
|
|
{
|
|
yawAlignComplete = true;
|
|
if (inFlight) {
|
|
finalInflightYawInit = true;
|
|
}
|
|
}
|
|
|
|
// return true and set the class variable true if the delta angle bias has been learned
|
|
bool NavEKF2_core::checkGyroCalStatus(void)
|
|
{
|
|
// check delta angle bias variances
|
|
const float delAngBiasVarMax = sq(radians(0.15f * dtEkfAvg));
|
|
delAngBiasLearned = (P[9][9] <= delAngBiasVarMax) &&
|
|
(P[10][10] <= delAngBiasVarMax) &&
|
|
(P[11][11] <= delAngBiasVarMax);
|
|
return delAngBiasLearned;
|
|
}
|
|
|
|
// Commands the EKF to not use GPS.
|
|
// This command must be sent prior to arming
|
|
// This command is forgotten by the EKF each time the vehicle disarms
|
|
// Returns 0 if command rejected
|
|
// Returns 1 if attitude, vertical velocity and vertical position will be provided
|
|
// Returns 2 if attitude, 3D-velocity, vertical position and relative horizontal position will be provided
|
|
uint8_t NavEKF2_core::setInhibitGPS(void)
|
|
{
|
|
if((PV_AidingMode == AID_ABSOLUTE) && motorsArmed) {
|
|
return 0;
|
|
} else {
|
|
gpsInhibit = true;
|
|
return 1;
|
|
}
|
|
// option 2 is not yet implemented as it requires a deeper integration of optical flow and GPS operation
|
|
}
|
|
|
|
// Update the filter status
|
|
void NavEKF2_core::updateFilterStatus(void)
|
|
{
|
|
// init return value
|
|
filterStatus.value = 0;
|
|
bool doingFlowNav = (PV_AidingMode == AID_RELATIVE) && flowDataValid;
|
|
bool doingWindRelNav = !tasTimeout && assume_zero_sideslip();
|
|
bool doingNormalGpsNav = !posTimeout && (PV_AidingMode == AID_ABSOLUTE);
|
|
bool someVertRefData = (!velTimeout && useGpsVertVel) || !hgtTimeout;
|
|
bool someHorizRefData = !(velTimeout && posTimeout && tasTimeout) || doingFlowNav;
|
|
bool optFlowNavPossible = flowDataValid && (frontend->_fusionModeGPS == 3) && delAngBiasLearned;
|
|
bool gpsNavPossible = !gpsNotAvailable && gpsGoodToAlign && delAngBiasLearned;
|
|
bool filterHealthy = healthy() && tiltAlignComplete && (yawAlignComplete || (!use_compass() && (PV_AidingMode == AID_NONE)));
|
|
// If GPS height usage is specified, height is considered to be inaccurate until the GPS passes all checks
|
|
bool hgtNotAccurate = (frontend->_altSource == 2) && !validOrigin;
|
|
|
|
// set individual flags
|
|
filterStatus.flags.attitude = !stateStruct.quat.is_nan() && filterHealthy; // attitude valid (we need a better check)
|
|
filterStatus.flags.horiz_vel = someHorizRefData && filterHealthy; // horizontal velocity estimate valid
|
|
filterStatus.flags.vert_vel = someVertRefData && filterHealthy; // vertical velocity estimate valid
|
|
filterStatus.flags.horiz_pos_rel = ((doingFlowNav && gndOffsetValid) || doingWindRelNav || doingNormalGpsNav) && filterHealthy; // relative horizontal position estimate valid
|
|
filterStatus.flags.horiz_pos_abs = doingNormalGpsNav && filterHealthy; // absolute horizontal position estimate valid
|
|
filterStatus.flags.vert_pos = !hgtTimeout && filterHealthy && !hgtNotAccurate; // vertical position estimate valid
|
|
filterStatus.flags.terrain_alt = gndOffsetValid && filterHealthy; // terrain height estimate valid
|
|
filterStatus.flags.const_pos_mode = (PV_AidingMode == AID_NONE) && filterHealthy; // constant position mode
|
|
filterStatus.flags.pred_horiz_pos_rel = ((optFlowNavPossible || gpsNavPossible) && filterHealthy) || filterStatus.flags.horiz_pos_rel; // we should be able to estimate a relative position when we enter flight mode
|
|
filterStatus.flags.pred_horiz_pos_abs = (gpsNavPossible && filterHealthy) || filterStatus.flags.horiz_pos_abs; // we should be able to estimate an absolute position when we enter flight mode
|
|
filterStatus.flags.takeoff_detected = takeOffDetected; // takeoff for optical flow navigation has been detected
|
|
filterStatus.flags.takeoff = expectGndEffectTakeoff; // The EKF has been told to expect takeoff and is in a ground effect mitigation mode
|
|
filterStatus.flags.touchdown = expectGndEffectTouchdown; // The EKF has been told to detect touchdown and is in a ground effect mitigation mode
|
|
filterStatus.flags.using_gps = ((imuSampleTime_ms - lastPosPassTime_ms) < 4000) && (PV_AidingMode == AID_ABSOLUTE);
|
|
filterStatus.flags.gps_glitching = !gpsAccuracyGood && (PV_AidingMode == AID_ABSOLUTE); // The GPS is glitching
|
|
}
|
|
|
|
#endif // HAL_CPU_CLASS
|