void Rover::send_rangefinder(mavlink_channel_t chan)
{
float distance_cm;
float voltage;
bool got_one = false;
// report smaller distance of all rangefinders
for (uint8_t i=0; i<rangefinder.num_sensors(); i++) {
AP_RangeFinder_Backend *s = rangefinder.get_backend(i);
if (s == nullptr) {
continue;
}
if (!got_one ||
s->distance_cm() < distance_cm) {
distance_cm = s->distance_cm();
voltage = s->voltage_mv();
got_one = true;
}
}
if (!got_one) {
// no relevant data found
return;
}
mavlink_msg_rangefinder_send(
chan,
distance_cm * 0.01f,
voltage);
}
MAV_DISTANCE_SENSOR RangeFinder::get_mav_distance_sensor_type_orient(enum Rotation orientation) const
{
AP_RangeFinder_Backend *backend = find_instance(orientation);
if (backend == nullptr) {
return MAV_DISTANCE_SENSOR_UNKNOWN;
}
return backend->get_mav_distance_sensor_type();
}
uint8_t RangeFinder::range_valid_count_orient(enum Rotation orientation) const
{
AP_RangeFinder_Backend *backend = find_instance(orientation);
if (backend == nullptr) {
return 0;
}
return backend->range_valid_count();
}
const Vector3f &RangeFinder::get_pos_offset_orient(enum Rotation orientation) const
{
AP_RangeFinder_Backend *backend = find_instance(orientation);
if (backend == nullptr) {
return pos_offset_zero;
}
return backend->get_pos_offset();
}
int16_t RangeFinder::ground_clearance_cm_orient(enum Rotation orientation) const
{
AP_RangeFinder_Backend *backend = find_instance(orientation);
if (backend == nullptr) {
return 0;
}
return backend->ground_clearance_cm();
}
bool RangeFinder::has_data_orient(enum Rotation orientation) const
{
AP_RangeFinder_Backend *backend = find_instance(orientation);
if (backend == nullptr) {
return false;
}
return backend->has_data();
}
uint16_t RangeFinder::voltage_mv_orient(enum Rotation orientation) const
{
AP_RangeFinder_Backend *backend = find_instance(orientation);
if (backend == nullptr) {
return 0;
}
return backend->voltage_mv();
}
RangeFinder::RangeFinder_Status RangeFinder::status_orient(enum Rotation orientation) const
{
AP_RangeFinder_Backend *backend = find_instance(orientation);
if (backend == nullptr) {
return RangeFinder_NotConnected;
}
return backend->status();
}
uint32_t RangeFinder::last_reading_ms(enum Rotation orientation) const
{
AP_RangeFinder_Backend *backend = find_instance(orientation);
if (backend == nullptr) {
return 0;
}
return backend->last_reading_ms();
}
// find first range finder instance with the specified orientation
AP_RangeFinder_Backend *RangeFinder::find_instance(enum Rotation orientation) const
{
for (uint8_t i=0; i<num_instances; i++) {
AP_RangeFinder_Backend *backend = get_backend(i);
if (backend == nullptr) {
continue;
}
if (backend->orientation() != orientation) {
continue;
}
return backend;
}
return nullptr;
}
// update error mask of sensors and subsystems. The mask
// uses the MAV_SYS_STATUS_* values from mavlink. If a bit is set
// then it indicates that the sensor or subsystem is present but
// not functioning correctly.
void Rover::update_sensor_status_flags(void)
{
// default sensors present
control_sensors_present = MAVLINK_SENSOR_PRESENT_DEFAULT;
// first what sensors/controllers we have
if (g.compass_enabled) {
control_sensors_present |= MAV_SYS_STATUS_SENSOR_3D_MAG; // compass present
}
if (gps.status() > AP_GPS::NO_GPS) {
control_sensors_present |= MAV_SYS_STATUS_SENSOR_GPS;
}
if (g2.visual_odom.enabled()) {
control_sensors_present |= MAV_SYS_STATUS_SENSOR_VISION_POSITION;
}
if (rover.DataFlash.logging_present()) { // primary logging only (usually File)
control_sensors_present |= MAV_SYS_STATUS_LOGGING;
}
if (rover.g2.proximity.get_status() > AP_Proximity::Proximity_NotConnected) {
control_sensors_present |= MAV_SYS_STATUS_SENSOR_LASER_POSITION;
}
// all present sensors enabled by default except rate control, attitude stabilization, yaw, altitude, position control and motor output which we will set individually
control_sensors_enabled = control_sensors_present & (~MAV_SYS_STATUS_SENSOR_ANGULAR_RATE_CONTROL &
~MAV_SYS_STATUS_SENSOR_ATTITUDE_STABILIZATION &
~MAV_SYS_STATUS_SENSOR_YAW_POSITION &
~MAV_SYS_STATUS_SENSOR_XY_POSITION_CONTROL &
~MAV_SYS_STATUS_SENSOR_MOTOR_OUTPUTS &
~MAV_SYS_STATUS_LOGGING &
~MAV_SYS_STATUS_SENSOR_BATTERY);
if (control_mode->attitude_stabilized()) {
control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_ANGULAR_RATE_CONTROL; // 3D angular rate control
control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_ATTITUDE_STABILIZATION; // 3D angular rate control
}
if (control_mode->is_autopilot_mode()) {
control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_YAW_POSITION; // yaw position
control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_XY_POSITION_CONTROL; // X/Y position control
}
if (rover.DataFlash.logging_enabled()) {
control_sensors_enabled |= MAV_SYS_STATUS_LOGGING;
}
// set motors outputs as enabled if safety switch is not disarmed (i.e. either NONE or ARMED)
if (hal.util->safety_switch_state() != AP_HAL::Util::SAFETY_DISARMED) {
control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_MOTOR_OUTPUTS;
}
if (battery.num_instances() > 0) {
control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_BATTERY;
}
// default to all healthy except compass and gps which we set individually
control_sensors_health = control_sensors_present & (~MAV_SYS_STATUS_SENSOR_3D_MAG & ~MAV_SYS_STATUS_SENSOR_GPS);
if (g.compass_enabled && compass.healthy(0) && ahrs.use_compass()) {
control_sensors_health |= MAV_SYS_STATUS_SENSOR_3D_MAG;
}
if (gps.is_healthy()) {
control_sensors_health |= MAV_SYS_STATUS_SENSOR_GPS;
}
if (g2.visual_odom.enabled() && !g2.visual_odom.healthy()) {
control_sensors_health &= ~MAV_SYS_STATUS_SENSOR_VISION_POSITION;
}
if (!ins.get_gyro_health_all() || !ins.gyro_calibrated_ok_all()) {
control_sensors_health &= ~MAV_SYS_STATUS_SENSOR_3D_GYRO;
}
if (!ins.get_accel_health_all()) {
control_sensors_health &= ~MAV_SYS_STATUS_SENSOR_3D_ACCEL;
}
if (ahrs.initialised() && !ahrs.healthy()) {
// AHRS subsystem is unhealthy
control_sensors_health &= ~MAV_SYS_STATUS_AHRS;
}
if (rangefinder.num_sensors() > 0) {
control_sensors_present |= MAV_SYS_STATUS_SENSOR_LASER_POSITION;
if (g.rangefinder_trigger_cm > 0) {
control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_LASER_POSITION;
}
AP_RangeFinder_Backend *s = rangefinder.get_backend(0);
if (s != nullptr && s->has_data()) {
control_sensors_health |= MAV_SYS_STATUS_SENSOR_LASER_POSITION;
}
}
if (rover.g2.proximity.get_status() < AP_Proximity::Proximity_Good) {
control_sensors_health &= ~MAV_SYS_STATUS_SENSOR_LASER_POSITION;
}
if (rover.DataFlash.logging_failed()) {
control_sensors_health &= ~MAV_SYS_STATUS_LOGGING;
}
if (!battery.healthy() || battery.has_failsafed()) {
control_sensors_enabled &= ~MAV_SYS_STATUS_SENSOR_BATTERY;
}
if (!initialised || ins.calibrating()) {
// while initialising the gyros and accels are not enabled
control_sensors_enabled &= ~(MAV_SYS_STATUS_SENSOR_3D_GYRO | MAV_SYS_STATUS_SENSOR_3D_ACCEL);
control_sensors_health &= ~(MAV_SYS_STATUS_SENSOR_3D_GYRO | MAV_SYS_STATUS_SENSOR_3D_ACCEL);
}
#if FRSKY_TELEM_ENABLED == ENABLED
// give mask of error flags to Frsky_Telemetry
frsky_telemetry.update_sensor_status_flags(~control_sensors_health & control_sensors_enabled & control_sensors_present);
#endif
}
// select the height measurement to be fused from the available baro, range finder and GPS sources
void NavEKF2_core::selectHeightForFusion()
{
// Read range finder data and check for new data in the buffer
// This data is used by both height and optical flow fusion processing
readRangeFinder();
rangeDataToFuse = storedRange.recall(rangeDataDelayed,imuDataDelayed.time_ms);
// correct range data for the body frame position offset relative to the IMU
// the corrected reading is the reading that would have been taken if the sensor was
// co-located with the IMU
if (rangeDataToFuse) {
AP_RangeFinder_Backend *sensor = frontend->_rng.get_backend(rangeDataDelayed.sensor_idx);
if (sensor != nullptr) {
Vector3f posOffsetBody = sensor->get_pos_offset() - accelPosOffset;
if (!posOffsetBody.is_zero()) {
Vector3f posOffsetEarth = prevTnb.mul_transpose(posOffsetBody);
rangeDataDelayed.rng += posOffsetEarth.z / prevTnb.c.z;
}
}
}
// read baro height data from the sensor and check for new data in the buffer
readBaroData();
baroDataToFuse = storedBaro.recall(baroDataDelayed, imuDataDelayed.time_ms);
// select height source
if (extNavUsedForPos) {
// always use external vision as the hight source if using for position.
activeHgtSource = HGT_SOURCE_EV;
} else if (((frontend->_useRngSwHgt > 0) || (frontend->_altSource == 1)) && (imuSampleTime_ms - rngValidMeaTime_ms < 500)) {
if (frontend->_altSource == 1) {
// always use range finder
activeHgtSource = HGT_SOURCE_RNG;
} else {
// determine if we are above or below the height switch region
float rangeMaxUse = 1e-4f * (float)frontend->_rng.max_distance_cm_orient(ROTATION_PITCH_270) * (float)frontend->_useRngSwHgt;
bool aboveUpperSwHgt = (terrainState - stateStruct.position.z) > rangeMaxUse;
bool belowLowerSwHgt = (terrainState - stateStruct.position.z) < 0.7f * rangeMaxUse;
// If the terrain height is consistent and we are moving slowly, then it can be
// used as a height reference in combination with a range finder
// apply a hysteresis to the speed check to prevent rapid switching
float horizSpeed = norm(stateStruct.velocity.x, stateStruct.velocity.y);
bool dontTrustTerrain = ((horizSpeed > frontend->_useRngSwSpd) && filterStatus.flags.horiz_vel) || !terrainHgtStable;
float trust_spd_trigger = MAX((frontend->_useRngSwSpd - 1.0f),(frontend->_useRngSwSpd * 0.5f));
bool trustTerrain = (horizSpeed < trust_spd_trigger) && terrainHgtStable;
/*
* Switch between range finder and primary height source using height above ground and speed thresholds with
* hysteresis to avoid rapid switching. Using range finder for height requires a consistent terrain height
* which cannot be assumed if the vehicle is moving horizontally.
*/
if ((aboveUpperSwHgt || dontTrustTerrain) && (activeHgtSource == HGT_SOURCE_RNG)) {
// cannot trust terrain or range finder so stop using range finder height
if (frontend->_altSource == 0) {
activeHgtSource = HGT_SOURCE_BARO;
} else if (frontend->_altSource == 2) {
activeHgtSource = HGT_SOURCE_GPS;
}
} else if (belowLowerSwHgt && trustTerrain && (activeHgtSource != HGT_SOURCE_RNG)) {
// reliable terrain and range finder so start using range finder height
activeHgtSource = HGT_SOURCE_RNG;
}
}
} else if ((frontend->_altSource == 2) && ((imuSampleTime_ms - lastTimeGpsReceived_ms) < 500) && validOrigin && gpsAccuracyGood) {
activeHgtSource = HGT_SOURCE_GPS;
} else if ((frontend->_altSource == 3) && validOrigin && rngBcnGoodToAlign) {
activeHgtSource = HGT_SOURCE_BCN;
} else {
activeHgtSource = HGT_SOURCE_BARO;
}
// Use Baro alt as a fallback if we lose range finder, GPS or external nav
bool lostRngHgt = ((activeHgtSource == HGT_SOURCE_RNG) && ((imuSampleTime_ms - rngValidMeaTime_ms) > 500));
bool lostGpsHgt = ((activeHgtSource == HGT_SOURCE_GPS) && ((imuSampleTime_ms - lastTimeGpsReceived_ms) > 2000));
bool lostExtNavHgt = ((activeHgtSource == HGT_SOURCE_EV) && ((imuSampleTime_ms - extNavMeasTime_ms) > 2000));
if (lostRngHgt || lostGpsHgt || lostExtNavHgt) {
activeHgtSource = HGT_SOURCE_BARO;
}
// if there is new baro data to fuse, calculate filtered baro data required by other processes
if (baroDataToFuse) {
// calculate offset to baro data that enables us to switch to Baro height use during operation
if (activeHgtSource != HGT_SOURCE_BARO) {
calcFiltBaroOffset();
}
// filtered baro data used to provide a reference for takeoff
// it is is reset to last height measurement on disarming in performArmingChecks()
if (!getTakeoffExpected()) {
const float gndHgtFiltTC = 0.5f;
const float dtBaro = frontend->hgtAvg_ms*1.0e-3f;
float alpha = constrain_float(dtBaro / (dtBaro+gndHgtFiltTC),0.0f,1.0f);
meaHgtAtTakeOff += (baroDataDelayed.hgt-meaHgtAtTakeOff)*alpha;
}
}
// If we are not using GPS as the primary height sensor, correct EKF origin height so that
// combined local NED position height and origin height remains consistent with the GPS altitude
// This also enables the GPS height to be used as a backup height source
if (gpsDataToFuse &&
(((frontend->_originHgtMode & (1 << 0)) && (activeHgtSource == HGT_SOURCE_BARO)) ||
((frontend->_originHgtMode & (1 << 1)) && (activeHgtSource == HGT_SOURCE_RNG)))
) {
correctEkfOriginHeight();
}
// Select the height measurement source
if (extNavDataToFuse && (activeHgtSource == HGT_SOURCE_EV)) {
hgtMea = -extNavDataDelayed.pos.z;
posDownObsNoise = sq(constrain_float(extNavDataDelayed.posErr, 0.1f, 10.0f));
} else if (rangeDataToFuse && (activeHgtSource == HGT_SOURCE_RNG)) {
// using range finder data
// correct for tilt using a flat earth model
if (prevTnb.c.z >= 0.7) {
// calculate height above ground
hgtMea = MAX(rangeDataDelayed.rng * prevTnb.c.z, rngOnGnd);
// correct for terrain position relative to datum
hgtMea -= terrainState;
// enable fusion
fuseHgtData = true;
velPosObs[5] = -hgtMea;
// set the observation noise
posDownObsNoise = sq(constrain_float(frontend->_rngNoise, 0.1f, 10.0f));
// add uncertainty created by terrain gradient and vehicle tilt
posDownObsNoise += sq(rangeDataDelayed.rng * frontend->_terrGradMax) * MAX(0.0f , (1.0f - sq(prevTnb.c.z)));
} else {
// disable fusion if tilted too far
fuseHgtData = false;
}
} else if (gpsDataToFuse && (activeHgtSource == HGT_SOURCE_GPS)) {
// using GPS data
hgtMea = gpsDataDelayed.hgt;
// enable fusion
velPosObs[5] = -hgtMea;
fuseHgtData = true;
// set the observation noise using receiver reported accuracy or the horizontal noise scaled for typical VDOP/HDOP ratio
if (gpsHgtAccuracy > 0.0f) {
posDownObsNoise = sq(constrain_float(gpsHgtAccuracy, 1.5f * frontend->_gpsHorizPosNoise, 100.0f));
} else {
posDownObsNoise = sq(constrain_float(1.5f * frontend->_gpsHorizPosNoise, 0.1f, 10.0f));
}
} else if (baroDataToFuse && (activeHgtSource == HGT_SOURCE_BARO)) {
// using Baro data
hgtMea = baroDataDelayed.hgt - baroHgtOffset;
// enable fusion
velPosObs[5] = -hgtMea;
fuseHgtData = true;
// set the observation noise
posDownObsNoise = sq(constrain_float(frontend->_baroAltNoise, 0.1f, 10.0f));
// reduce weighting (increase observation noise) on baro if we are likely to be in ground effect
if (getTakeoffExpected() || getTouchdownExpected()) {
posDownObsNoise *= frontend->gndEffectBaroScaler;
}
// If we are in takeoff mode, the height measurement is limited to be no less than the measurement at start of takeoff
// This prevents negative baro disturbances due to copter downwash corrupting the EKF altitude during initial ascent
if (motorsArmed && getTakeoffExpected()) {
hgtMea = MAX(hgtMea, meaHgtAtTakeOff);
}
} else {
fuseHgtData = false;
}
// If we haven't fused height data for a while, then declare the height data as being timed out
// set timeout period based on whether we have vertical GPS velocity available to constrain drift
hgtRetryTime_ms = (useGpsVertVel && !velTimeout) ? frontend->hgtRetryTimeMode0_ms : frontend->hgtRetryTimeMode12_ms;
if (imuSampleTime_ms - lastHgtPassTime_ms > hgtRetryTime_ms) {
hgtTimeout = true;
} else {
hgtTimeout = false;
}
}
