#include #include #include #include "AC_PrecLand.h" #include "AC_PrecLand_Backend.h" #include "AC_PrecLand_Companion.h" #include "AC_PrecLand_IRLock.h" #include "AC_PrecLand_SITL_Gazebo.h" #include "AC_PrecLand_SITL.h" #include #include #include extern const AP_HAL::HAL& hal; #if APM_BUILD_TYPE(APM_BUILD_Rover) # define AC_PRECLAND_ORIENT_DEFAULT Rotation::ROTATION_NONE #else # define AC_PRECLAND_ORIENT_DEFAULT Rotation::ROTATION_PITCH_270 #endif static const uint32_t EKF_INIT_TIME_MS = 2000; // EKF initialisation requires this many milliseconds of good sensor data static const uint32_t EKF_INIT_SENSOR_MIN_UPDATE_MS = 500; // Sensor must update within this many ms during EKF init, else init will fail static const uint32_t LANDING_TARGET_TIMEOUT_MS = 2000; // Sensor must update within this many ms, else prec landing will be switched off static const uint32_t LANDING_TARGET_LOST_TIMEOUT_MS = 180000; // Target will be considered as "lost" if the last known location of the target is more than this many ms ago static const float LANDING_TARGET_LOST_DIST_THRESH_M = 30; // If the last known location of the landing target is beyond this many meters, then we will consider it lost const AP_Param::GroupInfo AC_PrecLand::var_info[] = { // @Param: ENABLED // @DisplayName: Precision Land enabled/disabled // @Description: Precision Land enabled/disabled // @Values: 0:Disabled, 1:Enabled // @User: Advanced AP_GROUPINFO_FLAGS("ENABLED", 0, AC_PrecLand, _enabled, 0, AP_PARAM_FLAG_ENABLE), // @Param: TYPE // @DisplayName: Precision Land Type // @Description: Precision Land Type // @Values: 0:None, 1:CompanionComputer, 2:IRLock, 3:SITL_Gazebo, 4:SITL // @User: Advanced AP_GROUPINFO("TYPE", 1, AC_PrecLand, _type, 0), // @Param: YAW_ALIGN // @DisplayName: Sensor yaw alignment // @Description: Yaw angle from body x-axis to sensor x-axis. // @Range: 0 36000 // @Increment: 10 // @User: Advanced // @Units: cdeg AP_GROUPINFO("YAW_ALIGN", 2, AC_PrecLand, _yaw_align, 0), // @Param: LAND_OFS_X // @DisplayName: Land offset forward // @Description: Desired landing position of the camera forward of the target in vehicle body frame // @Range: -20 20 // @Increment: 1 // @User: Advanced // @Units: cm AP_GROUPINFO("LAND_OFS_X", 3, AC_PrecLand, _land_ofs_cm_x, 0), // @Param: LAND_OFS_Y // @DisplayName: Land offset right // @Description: desired landing position of the camera right of the target in vehicle body frame // @Range: -20 20 // @Increment: 1 // @User: Advanced // @Units: cm AP_GROUPINFO("LAND_OFS_Y", 4, AC_PrecLand, _land_ofs_cm_y, 0), // @Param: EST_TYPE // @DisplayName: Precision Land Estimator Type // @Description: Specifies the estimation method to be used // @Values: 0:RawSensor, 1:KalmanFilter // @User: Advanced AP_GROUPINFO("EST_TYPE", 5, AC_PrecLand, _estimator_type, 1), // @Param: ACC_P_NSE // @DisplayName: Kalman Filter Accelerometer Noise // @Description: Kalman Filter Accelerometer Noise, higher values weight the input from the camera more, accels less // @Range: 0.5 5 // @User: Advanced AP_GROUPINFO("ACC_P_NSE", 6, AC_PrecLand, _accel_noise, 2.5f), // @Param: CAM_POS_X // @DisplayName: Camera X position offset // @Description: X position of the camera in body frame. Positive X is forward of the origin. // @Units: m // @Range: -5 5 // @Increment: 0.01 // @User: Advanced // @Param: CAM_POS_Y // @DisplayName: Camera Y position offset // @Description: Y position of the camera in body frame. Positive Y is to the right of the origin. // @Units: m // @Range: -5 5 // @Increment: 0.01 // @User: Advanced // @Param: CAM_POS_Z // @DisplayName: Camera Z position offset // @Description: Z position of the camera in body frame. Positive Z is down from the origin. // @Units: m // @Range: -5 5 // @Increment: 0.01 // @User: Advanced AP_GROUPINFO("CAM_POS", 7, AC_PrecLand, _cam_offset, 0.0f), // @Param: BUS // @DisplayName: Sensor Bus // @Description: Precland sensor bus for I2C sensors. // @Values: -1:DefaultBus,0:InternalI2C,1:ExternalI2C // @User: Advanced AP_GROUPINFO("BUS", 8, AC_PrecLand, _bus, -1), // @Param: LAG // @DisplayName: Precision Landing sensor lag // @Description: Precision Landing sensor lag, to cope with variable landing_target latency // @Range: 0.02 0.250 // @Increment: 1 // @Units: s // @User: Advanced // @RebootRequired: True AP_GROUPINFO("LAG", 9, AC_PrecLand, _lag, 0.02f), // 20ms is the old default buffer size (8 frames @ 400hz/2.5ms) // @Param: XY_DIST_MAX // @DisplayName: Precision Landing maximum distance to target before descending // @Description: The vehicle will not start descending if the landing target is detected and it is further than this many meters away. Set 0 to always descend. // @Range: 0 10 // @Units: m // @User: Advanced AP_GROUPINFO("XY_DIST_MAX", 10, AC_PrecLand, _xy_max_dist_desc, 2.5f), // @Param: STRICT // @DisplayName: PrecLand strictness // @Description: How strictly should the vehicle land on the target if target is lost // @Values: 0: Land Vertically (Not strict), 1: Retry Landing(Normal Strictness), 2: Do not land (just Hover) (Very Strict) AP_GROUPINFO("STRICT", 11, AC_PrecLand, _strict, 1), // @Param: RET_MAX // @DisplayName: PrecLand Maximum number of retires for a failed landing // @Description: PrecLand Maximum number of retires for a failed landing. Set to zero to disable landing retry. // @Range: 0 10 // @Increment: 1 AP_GROUPINFO("RET_MAX", 12, AC_PrecLand, _retry_max, 4), // @Param: TIMEOUT // @DisplayName: PrecLand retry timeout // @Description: Time for which vehicle continues descend even if target is lost. After this time period, vehicle will attemp a landing retry depending on PLND_STRICT parameter. // @Range: 0 20 // @Units: s AP_GROUPINFO("TIMEOUT", 13, AC_PrecLand, _retry_timeout_sec, 4), // @Param: RET_BEHAVE // @DisplayName: PrecLand retry behaviour // @Description: Prec Land will do the action selected by this parameter if a retry to a landing is needed // @Values: 0: Go to the last location where landing target was detected, 1: Go towards the approximate location of the detected landing target AP_GROUPINFO("RET_BEHAVE", 14, AC_PrecLand, _retry_behave, 0), // @Param: ALT_MIN // @DisplayName: PrecLand minimum alt for retry // @Description: Vehicle will continue landing vertically even if target is lost below this height. This needs a rangefinder to work. Set to zero to disable this. // @Range: 0 5 // @Units: m AP_GROUPINFO("ALT_MIN", 15, AC_PrecLand, _sensor_min_alt, 0.75), // @Param: ALT_MAX // @DisplayName: PrecLand maximum alt for retry // @Description: Vehicle will continue landing vertically until this height if target is not found. Below this height if landing target is not found, landing retry/failsafe might be attempted. This needs a rangefinder to work. Set to zero to disable this. // @Range: 0 50 // @Units: m AP_GROUPINFO("ALT_MAX", 16, AC_PrecLand, _sensor_max_alt, 8), // @Param: OPTIONS // @DisplayName: Precision Landing Extra Options // @Description: Precision Landing Extra Options // @Bitmask: 0: Moving Landing Target // @User: Advanced AP_GROUPINFO("OPTIONS", 17, AC_PrecLand, _options, 0), // @Param: ORIENT // @DisplayName: Camera Orientation // @Description: Orientation of camera/sensor on body // @Values: 0:Forward, 4:Back, 25:Down // @User: Advanced // @RebootRequired: True AP_GROUPINFO_FRAME("ORIENT", 18, AC_PrecLand, _orient, AC_PRECLAND_ORIENT_DEFAULT, AP_PARAM_FRAME_ROVER), AP_GROUPEND }; // Default constructor. AC_PrecLand::AC_PrecLand() { if (_singleton != nullptr) { AP_HAL::panic("AC_PrecLand must be singleton"); } _singleton = this; // set parameters to defaults AP_Param::setup_object_defaults(this, var_info); } // perform any required initialisation of landing controllers // update_rate_hz should be the rate at which the update method will be called in hz void AC_PrecLand::init(uint16_t update_rate_hz) { // exit immediately if init has already been run if (_backend != nullptr) { return; } // init as target TARGET_NEVER_SEEN, we will update this later _current_target_state = TargetState::TARGET_NEVER_SEEN; // default health to false _backend = nullptr; _backend_state.healthy = false; // create inertial history buffer // constrain lag parameter to be within bounds _lag.set(constrain_float(_lag, 0.02f, 0.25f)); // calculate inertial buffer size from lag and minimum of main loop rate and update_rate_hz argument const uint16_t inertial_buffer_size = MAX((uint16_t)roundf(_lag * MIN(update_rate_hz, AP::scheduler().get_loop_rate_hz())), 1); // instantiate ring buffer to hold inertial history, return on failure so no backends are created _inertial_history = new ObjectArray(inertial_buffer_size); if (_inertial_history == nullptr) { return; } // instantiate backend based on type parameter switch ((Type)(_type.get())) { // no type defined case Type::NONE: default: return; // companion computer case Type::COMPANION: _backend = new AC_PrecLand_Companion(*this, _backend_state); break; // IR Lock case Type::IRLOCK: _backend = new AC_PrecLand_IRLock(*this, _backend_state); break; #if CONFIG_HAL_BOARD == HAL_BOARD_SITL case Type::SITL_GAZEBO: _backend = new AC_PrecLand_SITL_Gazebo(*this, _backend_state); break; case Type::SITL: _backend = new AC_PrecLand_SITL(*this, _backend_state); break; #endif } // init backend if (_backend != nullptr) { _backend->init(); } _approach_vector_body.x = 1; _approach_vector_body.rotate(_orient); } // update - give chance to driver to get updates from sensor void AC_PrecLand::update(float rangefinder_alt_cm, bool rangefinder_alt_valid) { // exit immediately if not enabled if (_backend == nullptr || _inertial_history == nullptr) { return; } // append current velocity and attitude correction into history buffer struct inertial_data_frame_s inertial_data_newest; const auto &_ahrs = AP::ahrs(); _ahrs.getCorrectedDeltaVelocityNED(inertial_data_newest.correctedVehicleDeltaVelocityNED, inertial_data_newest.dt); inertial_data_newest.Tbn = _ahrs.get_rotation_body_to_ned(); Vector3f curr_vel; nav_filter_status status; if (!_ahrs.get_velocity_NED(curr_vel) || !_ahrs.get_filter_status(status)) { inertial_data_newest.inertialNavVelocityValid = false; } else { inertial_data_newest.inertialNavVelocityValid = status.flags.horiz_vel; } curr_vel.z = -curr_vel.z; // NED to NEU inertial_data_newest.inertialNavVelocity = curr_vel; inertial_data_newest.time_usec = AP_HAL::micros64(); _inertial_history->push_force(inertial_data_newest); const float rangefinder_alt_m = rangefinder_alt_cm*0.01f; //cm to meter // update estimator of target position if (_backend != nullptr && _enabled) { _backend->update(); run_estimator(rangefinder_alt_m, rangefinder_alt_valid); } // check the status of the landing target location check_target_status(rangefinder_alt_m, rangefinder_alt_valid); const uint32_t now = AP_HAL::millis(); if (now - last_log_ms > 40) { // 25Hz last_log_ms = now; Write_Precland(); } } // check the status of the target void AC_PrecLand::check_target_status(float rangefinder_alt_m, bool rangefinder_alt_valid) { if (target_acquired()) { // target in sight _current_target_state = TargetState::TARGET_FOUND; // early return because we already know the status return; } // target not in sight if (_current_target_state == TargetState::TARGET_FOUND || _current_target_state == TargetState::TARGET_RECENTLY_LOST) { // we had target in sight, but not any more, i.e we have lost the target _current_target_state = TargetState::TARGET_RECENTLY_LOST; } else { // we never had the target in sight _current_target_state = TargetState::TARGET_NEVER_SEEN; } // We definitely do not have the target in sight // check if the precision landing sensor is supposed to be in range // this needs a valid rangefinder to work if (!check_if_sensor_in_range(rangefinder_alt_m, rangefinder_alt_valid)) { // Target is not in range (vehicle is either too high or too low). Vehicle will not be attempting any sort of landing retries during this period _current_target_state = TargetState::TARGET_OUT_OF_RANGE; return; } if (_current_target_state == TargetState::TARGET_RECENTLY_LOST) { // check if it's nearby/found recently, else the status will be demoted to "TARGET_LOST" Vector2f curr_pos; if (AP::ahrs().get_relative_position_NE_origin(curr_pos)) { const float dist_to_last_target_loc_xy = (curr_pos - Vector2f{_last_target_pos_rel_origin_NED.x, _last_target_pos_rel_origin_NED.y}).length(); const float dist_to_last_loc_xy = (curr_pos - Vector2f{_last_vehicle_pos_NED.x, _last_vehicle_pos_NED.y}).length(); if ((AP_HAL::millis() - _last_valid_target_ms) > LANDING_TARGET_LOST_TIMEOUT_MS) { // the target has not been seen for a long time // might as well consider it as "never seen" _current_target_state = TargetState::TARGET_NEVER_SEEN; return; } if ((dist_to_last_target_loc_xy > LANDING_TARGET_LOST_DIST_THRESH_M) || (dist_to_last_loc_xy > LANDING_TARGET_LOST_DIST_THRESH_M)) { // the last known location of target is too far away _current_target_state = TargetState::TARGET_NEVER_SEEN; return; } } } } // Check if the landing target is supposed to be in sight based on the height of the vehicle from the ground // This needs a valid rangefinder to work, if the min/max parameters are non zero bool AC_PrecLand::check_if_sensor_in_range(float rangefinder_alt_m, bool rangefinder_alt_valid) const { if (is_zero(_sensor_max_alt) && is_zero(_sensor_min_alt)) { // no sensor limits have been specified, assume sensor is always in range return true; } if (!rangefinder_alt_valid) { // rangefinder isn't healthy. We might be at a very high altitude return false; } if (rangefinder_alt_m > _sensor_max_alt && !is_zero(_sensor_max_alt)) { // this prevents triggering a retry when we are too far away from the target return false; } if (rangefinder_alt_m < _sensor_min_alt && !is_zero(_sensor_min_alt)) { // this prevents triggering a retry when we are very close to the target return false; } // target should be in range return true; } bool AC_PrecLand::target_acquired() { if ((AP_HAL::millis()-_last_update_ms) > LANDING_TARGET_TIMEOUT_MS) { if (_target_acquired) { // just lost the landing target, inform the user. This message will only be sent once everytime target is lost gcs().send_text(MAV_SEVERITY_CRITICAL, "PrecLand: Target Lost"); } // not had a sensor update since a long time // probably lost the target _estimator_initialized = false; _target_acquired = false; } return _target_acquired; } bool AC_PrecLand::get_target_position_cm(Vector2f& ret) { if (!target_acquired()) { return false; } Vector2f curr_pos; if (!AP::ahrs().get_relative_position_NE_origin(curr_pos)) { return false; } ret.x = (_target_pos_rel_out_NE.x + curr_pos.x) * 100.0f; // m to cm ret.y = (_target_pos_rel_out_NE.y + curr_pos.y) * 100.0f; // m to cm return true; } void AC_PrecLand::get_target_position_measurement_cm(Vector3f& ret) { ret = _target_pos_rel_meas_NED*100.0f; return; } bool AC_PrecLand::get_target_position_relative_cm(Vector2f& ret) { if (!target_acquired()) { return false; } ret = _target_pos_rel_out_NE*100.0f; return true; } bool AC_PrecLand::get_target_velocity_relative_cms(Vector2f& ret) { if (!target_acquired()) { return false; } ret = _target_vel_rel_out_NE*100.0f; return true; } // get the absolute velocity of the vehicle void AC_PrecLand::get_target_velocity_cms(const Vector2f& vehicle_velocity_cms, Vector2f& target_vel_cms) { if (!(_options & PLND_OPTION_MOVING_TARGET)) { // the target should not be moving target_vel_cms.zero(); return; } if ((EstimatorType)_estimator_type.get() == EstimatorType::RAW_SENSOR) { // We do not predict the velocity of the target in this case // assume velocity to be zero target_vel_cms.zero(); return; } Vector2f target_vel_rel_cms; if (!get_target_velocity_relative_cms(target_vel_rel_cms)) { // Don't know where the target is // assume velocity to be zero target_vel_cms.zero(); return; } // return the absolute velocity target_vel_cms = target_vel_rel_cms + vehicle_velocity_cms; } // handle_msg - Process a LANDING_TARGET mavlink message void AC_PrecLand::handle_msg(const mavlink_landing_target_t &packet, uint32_t timestamp_ms) { // run backend update if (_backend != nullptr) { _backend->handle_msg(packet, timestamp_ms); } } // // Private methods // void AC_PrecLand::run_estimator(float rangefinder_alt_m, bool rangefinder_alt_valid) { const struct inertial_data_frame_s *inertial_data_delayed = (*_inertial_history)[0]; switch ((EstimatorType)_estimator_type.get()) { case EstimatorType::RAW_SENSOR: { // Return if there's any invalid velocity data for (uint8_t i=0; i<_inertial_history->available(); i++) { const struct inertial_data_frame_s *inertial_data = (*_inertial_history)[i]; if (!inertial_data->inertialNavVelocityValid) { _target_acquired = false; return; } } // Predict if (target_acquired()) { _target_pos_rel_est_NE.x -= inertial_data_delayed->inertialNavVelocity.x * inertial_data_delayed->dt; _target_pos_rel_est_NE.y -= inertial_data_delayed->inertialNavVelocity.y * inertial_data_delayed->dt; _target_vel_rel_est_NE.x = -inertial_data_delayed->inertialNavVelocity.x; _target_vel_rel_est_NE.y = -inertial_data_delayed->inertialNavVelocity.y; } // Update if a new Line-Of-Sight measurement is available if (construct_pos_meas_using_rangefinder(rangefinder_alt_m, rangefinder_alt_valid)) { if (!_estimator_initialized) { gcs().send_text(MAV_SEVERITY_INFO, "PrecLand: Target Found"); _estimator_initialized = true; } _target_pos_rel_est_NE.x = _target_pos_rel_meas_NED.x; _target_pos_rel_est_NE.y = _target_pos_rel_meas_NED.y; _target_vel_rel_est_NE.x = -inertial_data_delayed->inertialNavVelocity.x; _target_vel_rel_est_NE.y = -inertial_data_delayed->inertialNavVelocity.y; _last_update_ms = AP_HAL::millis(); _target_acquired = true; } // Output prediction if (target_acquired()) { run_output_prediction(); } break; } case EstimatorType::KALMAN_FILTER: { // Predict if (target_acquired() || _estimator_initialized) { const float& dt = inertial_data_delayed->dt; const Vector3f& vehicleDelVel = inertial_data_delayed->correctedVehicleDeltaVelocityNED; _ekf_x.predict(dt, -vehicleDelVel.x, _accel_noise*dt); _ekf_y.predict(dt, -vehicleDelVel.y, _accel_noise*dt); } // Update if a new Line-Of-Sight measurement is available if (construct_pos_meas_using_rangefinder(rangefinder_alt_m, rangefinder_alt_valid)) { float xy_pos_var = sq(_target_pos_rel_meas_NED.z*(0.01f + 0.01f*AP::ahrs().get_gyro().length()) + 0.02f); if (!_estimator_initialized) { // Inform the user landing target has been found gcs().send_text(MAV_SEVERITY_INFO, "PrecLand: Target Found"); // start init of EKF. We will let the filter consume the data for a while before it available for consumption // reset filter state if (inertial_data_delayed->inertialNavVelocityValid) { _ekf_x.init(_target_pos_rel_meas_NED.x, xy_pos_var, -inertial_data_delayed->inertialNavVelocity.x, sq(2.0f)); _ekf_y.init(_target_pos_rel_meas_NED.y, xy_pos_var, -inertial_data_delayed->inertialNavVelocity.y, sq(2.0f)); } else { _ekf_x.init(_target_pos_rel_meas_NED.x, xy_pos_var, 0.0f, sq(10.0f)); _ekf_y.init(_target_pos_rel_meas_NED.y, xy_pos_var, 0.0f, sq(10.0f)); } _last_update_ms = AP_HAL::millis(); _estimator_init_ms = AP_HAL::millis(); // we have initialized the estimator but will not use the values for sometime so that EKF settles down _estimator_initialized = true; } else { float NIS_x = _ekf_x.getPosNIS(_target_pos_rel_meas_NED.x, xy_pos_var); float NIS_y = _ekf_y.getPosNIS(_target_pos_rel_meas_NED.y, xy_pos_var); if (MAX(NIS_x, NIS_y) < 3.0f || _outlier_reject_count >= 3) { _outlier_reject_count = 0; _ekf_x.fusePos(_target_pos_rel_meas_NED.x, xy_pos_var); _ekf_y.fusePos(_target_pos_rel_meas_NED.y, xy_pos_var); _last_update_ms = AP_HAL::millis(); } else { _outlier_reject_count++; } } } // check EKF was properly initialized when the sensor detected a landing target check_ekf_init_timeout(); // Output prediction if (target_acquired()) { _target_pos_rel_est_NE.x = _ekf_x.getPos(); _target_pos_rel_est_NE.y = _ekf_y.getPos(); _target_vel_rel_est_NE.x = _ekf_x.getVel(); _target_vel_rel_est_NE.y = _ekf_y.getVel(); run_output_prediction(); } break; } } } // check if EKF got the time to initialize when the landing target was first detected // Expects sensor to update within EKF_INIT_SENSOR_MIN_UPDATE_MS milliseconds till EKF_INIT_TIME_MS milliseconds have passed // after this period landing target estimates can be used by vehicle void AC_PrecLand::check_ekf_init_timeout() { if (!target_acquired() && _estimator_initialized) { // we have just got the target in sight if (AP_HAL::millis()-_last_update_ms > EKF_INIT_SENSOR_MIN_UPDATE_MS) { // we have lost the target, not enough readings to initialize the EKF _estimator_initialized = false; gcs().send_text(MAV_SEVERITY_CRITICAL, "PrecLand: Init Failed"); } else if (AP_HAL::millis()-_estimator_init_ms > EKF_INIT_TIME_MS) { // the target has been visible for a while, EKF should now have initialized to a good value _target_acquired = true; gcs().send_text(MAV_SEVERITY_INFO, "PrecLand: Init Complete"); } } } bool AC_PrecLand::retrieve_los_meas(Vector3f& target_vec_unit_body) { if (_backend->have_los_meas() && _backend->los_meas_time_ms() != _last_backend_los_meas_ms) { _last_backend_los_meas_ms = _backend->los_meas_time_ms(); _backend->get_los_body(target_vec_unit_body); if (!is_zero(_yaw_align)) { // Apply sensor yaw alignment rotation target_vec_unit_body.rotate_xy(radians(_yaw_align*0.01f)); } // rotate vector based on sensor oriention to get correct body frame vector if (_orient != ROTATION_PITCH_270) { // by default, the vector is constructed downwards in body frame // hence, we do not do any rotation if the orientation is downwards // if it is some other orientation, we first bring the vector to forward // and then we rotate it to desired orientation // because the rotations are measured with respect to a vector pointing towards front in body frame // for eg, if orientation is back, i.e., ROTATION_YAW_180, // the vector is first brought to front and then rotation by YAW 180 to take it to the back of vehicle target_vec_unit_body.rotate(ROTATION_PITCH_90); // bring vector to front target_vec_unit_body.rotate(_orient); // rotate it to desired orientation } return true; } else { return false; } } bool AC_PrecLand::construct_pos_meas_using_rangefinder(float rangefinder_alt_m, bool rangefinder_alt_valid) { Vector3f target_vec_unit_body; if (retrieve_los_meas(target_vec_unit_body)) { const struct inertial_data_frame_s *inertial_data_delayed = (*_inertial_history)[0]; const bool target_vec_valid = target_vec_unit_body.projected(_approach_vector_body).dot(_approach_vector_body) > 0.0f; const Vector3f target_vec_unit_ned = inertial_data_delayed->Tbn * target_vec_unit_body; const Vector3f approach_vector_NED = inertial_data_delayed->Tbn * _approach_vector_body; const bool alt_valid = (rangefinder_alt_valid && rangefinder_alt_m > 0.0f) || (_backend->distance_to_target() > 0.0f); if (target_vec_valid && alt_valid) { // distance to target and distance to target along approach vector float dist_to_target, dist_to_target_along_av; // figure out ned camera orientation w.r.t its offset Vector3f cam_pos_ned; if (!_cam_offset.get().is_zero()) { // user has specifed offset for camera // take its height into account while calculating distance cam_pos_ned = inertial_data_delayed->Tbn * _cam_offset; } if (_backend->distance_to_target() > 0.0f) { // sensor has provided distance to landing target dist_to_target = _backend->distance_to_target(); } else { // sensor only knows the horizontal location of the landing target // rely on rangefinder for the vertical target dist_to_target_along_av = MAX(rangefinder_alt_m - cam_pos_ned.projected(approach_vector_NED).length(), 0.0f); dist_to_target = dist_to_target_along_av / target_vec_unit_ned.projected(approach_vector_NED).length(); } // Compute camera position relative to IMU const Vector3f accel_pos_ned = inertial_data_delayed->Tbn * AP::ins().get_imu_pos_offset(AP::ahrs().get_primary_accel_index()); const Vector3f cam_pos_ned_rel_imu = cam_pos_ned - accel_pos_ned; // Compute target position relative to IMU _target_pos_rel_meas_NED = (target_vec_unit_ned * dist_to_target) + cam_pos_ned_rel_imu; // store the current relative down position so that if we need to retry landing, we know at this height landing target can be found const AP_AHRS &_ahrs = AP::ahrs(); Vector3f pos_NED; if (_ahrs.get_relative_position_NED_origin(pos_NED)) { _last_target_pos_rel_origin_NED.z = pos_NED.z; _last_vehicle_pos_NED = pos_NED; } return true; } } return false; } void AC_PrecLand::run_output_prediction() { _target_pos_rel_out_NE = _target_pos_rel_est_NE; _target_vel_rel_out_NE = _target_vel_rel_est_NE; // Predict forward from delayed time horizon for (uint8_t i=1; i<_inertial_history->available(); i++) { const struct inertial_data_frame_s *inertial_data = (*_inertial_history)[i]; _target_vel_rel_out_NE.x -= inertial_data->correctedVehicleDeltaVelocityNED.x; _target_vel_rel_out_NE.y -= inertial_data->correctedVehicleDeltaVelocityNED.y; _target_pos_rel_out_NE.x += _target_vel_rel_out_NE.x * inertial_data->dt; _target_pos_rel_out_NE.y += _target_vel_rel_out_NE.y * inertial_data->dt; } const AP_AHRS &_ahrs = AP::ahrs(); const Matrix3f& Tbn = (*_inertial_history)[_inertial_history->available()-1]->Tbn; Vector3f accel_body_offset = AP::ins().get_imu_pos_offset(_ahrs.get_primary_accel_index()); // Apply position correction for CG offset from IMU Vector3f imu_pos_ned = Tbn * accel_body_offset; _target_pos_rel_out_NE.x += imu_pos_ned.x; _target_pos_rel_out_NE.y += imu_pos_ned.y; // Apply position correction for body-frame horizontal camera offset from CG, so that vehicle lands lens-to-target Vector3f cam_pos_horizontal_ned = Tbn * Vector3f(_cam_offset.get().x, _cam_offset.get().y, 0); _target_pos_rel_out_NE.x -= cam_pos_horizontal_ned.x; _target_pos_rel_out_NE.y -= cam_pos_horizontal_ned.y; // Apply velocity correction for IMU offset from CG Vector3f vel_ned_rel_imu = Tbn * (_ahrs.get_gyro() % (-accel_body_offset)); _target_vel_rel_out_NE.x -= vel_ned_rel_imu.x; _target_vel_rel_out_NE.y -= vel_ned_rel_imu.y; // Apply land offset Vector3f land_ofs_ned_m = _ahrs.get_rotation_body_to_ned() * Vector3f(_land_ofs_cm_x,_land_ofs_cm_y,0) * 0.01f; _target_pos_rel_out_NE.x += land_ofs_ned_m.x; _target_pos_rel_out_NE.y += land_ofs_ned_m.y; // store the landing target as a offset from current position. This is used in landing retry Vector2f last_target_loc_rel_origin_2d; get_target_position_cm(last_target_loc_rel_origin_2d); _last_target_pos_rel_origin_NED.x = last_target_loc_rel_origin_2d.x * 0.01f; _last_target_pos_rel_origin_NED.y = last_target_loc_rel_origin_2d.y * 0.01f; // record the last time there was a target output _last_valid_target_ms = AP_HAL::millis(); } // Write a precision landing entry void AC_PrecLand::Write_Precland() { // exit immediately if not enabled if (!enabled()) { return; } Vector3f target_pos_meas; Vector2f target_pos_rel; Vector2f target_vel_rel; get_target_position_relative_cm(target_pos_rel); get_target_velocity_relative_cms(target_vel_rel); get_target_position_measurement_cm(target_pos_meas); const struct log_Precland pkt { LOG_PACKET_HEADER_INIT(LOG_PRECLAND_MSG), time_us : AP_HAL::micros64(), healthy : healthy(), target_acquired : target_acquired(), pos_x : target_pos_rel.x, pos_y : target_pos_rel.y, vel_x : target_vel_rel.x, vel_y : target_vel_rel.y, meas_x : target_pos_meas.x, meas_y : target_pos_meas.y, meas_z : target_pos_meas.z, last_meas : last_backend_los_meas_ms(), ekf_outcount : ekf_outlier_count(), estimator : (uint8_t)_estimator_type }; AP::logger().WriteBlock(&pkt, sizeof(pkt)); } // singleton instance AC_PrecLand *AC_PrecLand::_singleton; namespace AP { AC_PrecLand *ac_precland() { return AC_PrecLand::get_singleton(); } }