forked from Archive/PX4-Autopilot
1447 lines
57 KiB
C++
1447 lines
57 KiB
C++
/****************************************************************************
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*
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* Copyright (c) 2015 Estimation and Control Library (ECL). All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name ECL nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/**
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* @file control.cpp
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* Control functions for ekf attitude and position estimator.
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*
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* @author Paul Riseborough <p_riseborough@live.com.au>
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*
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*/
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#include "../ecl.h"
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#include "ekf.h"
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#include <mathlib/mathlib.h>
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void Ekf::controlFusionModes()
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{
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// Store the status to enable change detection
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_control_status_prev.value = _control_status.value;
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// monitor the tilt alignment
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if (!_control_status.flags.tilt_align) {
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// whilst we are aligning the tilt, monitor the variances
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Vector3f angle_err_var_vec = calcRotVecVariances();
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// Once the tilt variances have reduced to equivalent of 3deg uncertainty, re-set the yaw and magnetic field states
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// and declare the tilt alignment complete
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if ((angle_err_var_vec(0) + angle_err_var_vec(1)) < sq(math::radians(3.0f))) {
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_control_status.flags.tilt_align = true;
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_control_status.flags.yaw_align = resetMagHeading(_mag_lpf.getState());
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// send alignment status message to the console
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if (_control_status.flags.baro_hgt) {
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ECL_INFO("EKF aligned, (pressure height, IMU buf: %i, OBS buf: %i)", (int)_imu_buffer_length, (int)_obs_buffer_length);
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} else if (_control_status.flags.ev_hgt) {
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ECL_INFO("EKF aligned, (EV height, IMU buf: %i, OBS buf: %i)", (int)_imu_buffer_length, (int)_obs_buffer_length);
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} else if (_control_status.flags.gps_hgt) {
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ECL_INFO("EKF aligned, (GPS height, IMU buf: %i, OBS buf: %i)", (int)_imu_buffer_length, (int)_obs_buffer_length);
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} else if (_control_status.flags.rng_hgt) {
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ECL_INFO("EKF aligned, (range height, IMU buf: %i, OBS buf: %i)", (int)_imu_buffer_length, (int)_obs_buffer_length);
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} else {
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ECL_ERR("EKF aligned, (unknown height, IMU buf: %i, OBS buf: %i)", (int)_imu_buffer_length, (int)_obs_buffer_length);
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}
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}
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}
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// check for intermittent data (before pop_first_older_than)
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const baroSample &baro_init = _baro_buffer.get_newest();
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_baro_hgt_faulty = !((_time_last_imu - baro_init.time_us) < 2 * BARO_MAX_INTERVAL);
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const gpsSample &gps_init = _gps_buffer.get_newest();
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_gps_hgt_intermittent = !((_time_last_imu - gps_init.time_us) < 2 * GPS_MAX_INTERVAL);
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// check for arrival of new sensor data at the fusion time horizon
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_gps_data_ready = _gps_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_gps_sample_delayed);
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_mag_data_ready = _mag_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_mag_sample_delayed);
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if (_mag_data_ready) {
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// if enabled, use knowledge of theoretical magnetic field vector to calculate a synthetic magnetomter Z component value.
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// this is useful if there is a lot of interference on the sensor measurement.
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if (_params.synthesize_mag_z && (_params.mag_declination_source & MASK_USE_GEO_DECL) &&_NED_origin_initialised) {
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Vector3f mag_earth_pred = Dcmf(Eulerf(0, -_mag_inclination_gps, _mag_declination_gps)) * Vector3f(_mag_strength_gps, 0, 0);
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_mag_sample_delayed.mag(2) = calculate_synthetic_mag_z_measurement(_mag_sample_delayed.mag, mag_earth_pred);
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_control_status.flags.synthetic_mag_z = true;
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} else {
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_control_status.flags.synthetic_mag_z = false;
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}
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}
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_delta_time_baro_us = _baro_sample_delayed.time_us;
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_baro_data_ready = _baro_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_baro_sample_delayed);
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// if we have a new baro sample save the delta time between this sample and the last sample which is
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// used below for baro offset calculations
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if (_baro_data_ready) {
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_delta_time_baro_us = _baro_sample_delayed.time_us - _delta_time_baro_us;
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}
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// calculate 2,2 element of rotation matrix from sensor frame to earth frame
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// this is required for use of range finder and flow data
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_R_rng_to_earth_2_2 = _R_to_earth(2, 0) * _sin_tilt_rng + _R_to_earth(2, 2) * _cos_tilt_rng;
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// Get range data from buffer and check validity
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_range_data_ready = _range_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_range_sample_delayed);
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updateRangeDataValidity();
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if (_range_data_ready && _rng_hgt_valid) {
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// correct the range data for position offset relative to the IMU
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Vector3f pos_offset_body = _params.rng_pos_body - _params.imu_pos_body;
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Vector3f pos_offset_earth = _R_to_earth * pos_offset_body;
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_range_sample_delayed.rng += pos_offset_earth(2) / _R_rng_to_earth_2_2;
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}
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// We don't fuse flow data immediately because we have to wait for the mid integration point to fall behind the fusion time horizon.
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// This means we stop looking for new data until the old data has been fused.
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if (!_flow_data_ready) {
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_flow_data_ready = _flow_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_flow_sample_delayed)
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&& (_R_to_earth(2, 2) > _params.range_cos_max_tilt);
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}
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// check if we should fuse flow data for terrain estimation
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if (!_flow_for_terrain_data_ready && _flow_data_ready && _control_status.flags.in_air) {
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// only fuse flow for terrain if range data hasn't been fused for 5 seconds
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_flow_for_terrain_data_ready = (_time_last_imu - _time_last_hagl_fuse) > 5 * 1000 * 1000;
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// only fuse flow for terrain if the main filter is not fusing flow and we are using gps
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_flow_for_terrain_data_ready &= (!_control_status.flags.opt_flow && _control_status.flags.gps);
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}
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_ev_data_ready = _ext_vision_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_ev_sample_delayed);
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_tas_data_ready = _airspeed_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_airspeed_sample_delayed);
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// check for height sensor timeouts and reset and change sensor if necessary
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controlHeightSensorTimeouts();
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// control use of observations for aiding
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controlMagFusion();
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controlOpticalFlowFusion();
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controlGpsFusion();
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controlAirDataFusion();
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controlBetaFusion();
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controlDragFusion();
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controlHeightFusion();
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// Additional data odoemtery data from an external estimator can be fused.
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controlExternalVisionFusion();
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// Additional horizontal velocity data from an auxiliary sensor can be fused
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controlAuxVelFusion();
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// Fake position measurement for constraining drift when no other velocity or position measurements
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controlFakePosFusion();
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// check if we are no longer fusing measurements that directly constrain velocity drift
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update_deadreckoning_status();
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}
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void Ekf::controlExternalVisionFusion()
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{
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// Check for new external vision data
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if (_ev_data_ready) {
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// if the ev data is not in a NED reference frame, then the transformation between EV and EKF navigation frames
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// needs to be calculated and the observations rotated into the EKF frame of reference
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if ((_params.fusion_mode & MASK_ROTATE_EV) && ((_params.fusion_mode & MASK_USE_EVPOS) || (_params.fusion_mode & MASK_USE_EVVEL)) && !_control_status.flags.ev_yaw) {
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// rotate EV measurements into the EKF Navigation frame
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calcExtVisRotMat();
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}
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// external vision aiding selection logic
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if (_control_status.flags.tilt_align && _control_status.flags.yaw_align) {
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// check for a external vision measurement that has fallen behind the fusion time horizon
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if ((_time_last_imu - _time_last_ext_vision) < (2 * EV_MAX_INTERVAL)) {
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// turn on use of external vision measurements for position
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if (_params.fusion_mode & MASK_USE_EVPOS && !_control_status.flags.ev_pos) {
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_control_status.flags.ev_pos = true;
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resetPosition();
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ECL_INFO_TIMESTAMPED("EKF commencing external vision position fusion");
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}
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// turn on use of external vision measurements for velocity
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if (_params.fusion_mode & MASK_USE_EVVEL && !_control_status.flags.ev_vel) {
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_control_status.flags.ev_vel = true;
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resetVelocity();
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ECL_INFO_TIMESTAMPED("EKF commencing external vision velocity fusion");
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}
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if ((_params.fusion_mode & MASK_ROTATE_EV) && !(_params.fusion_mode & MASK_USE_EVYAW)
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&& !_ev_rot_mat_initialised) {
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// Reset transformation between EV and EKF navigation frames when starting fusion
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resetExtVisRotMat();
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_ev_rot_mat_initialised = true;
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ECL_INFO_TIMESTAMPED("EKF external vision aligned");
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}
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}
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}
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// external vision yaw aiding selection logic
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if (!_control_status.flags.gps && (_params.fusion_mode & MASK_USE_EVYAW) && !_control_status.flags.ev_yaw && _control_status.flags.tilt_align) {
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// don't start using EV data unless daa is arriving frequently
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if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
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// reset the yaw angle to the value from the observation quaternion
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// get the roll, pitch, yaw estimates from the quaternion states
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Quatf q_init(_state.quat_nominal);
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Eulerf euler_init(q_init);
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// get initial yaw from the observation quaternion
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const extVisionSample &ev_newest = _ext_vision_buffer.get_newest();
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Quatf q_obs(ev_newest.quat);
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Eulerf euler_obs(q_obs);
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euler_init(2) = euler_obs(2);
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// save a copy of the quaternion state for later use in calculating the amount of reset change
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Quatf quat_before_reset = _state.quat_nominal;
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// calculate initial quaternion states for the ekf
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_state.quat_nominal = Quatf(euler_init);
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uncorrelateQuatStates();
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// adjust the quaternion covariances estimated yaw error
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increaseQuatYawErrVariance(sq(fmaxf(_ev_sample_delayed.angErr, 1.0e-2f)));
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// calculate the amount that the quaternion has changed by
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_state_reset_status.quat_change = _state.quat_nominal * quat_before_reset.inversed();
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// add the reset amount to the output observer buffered data
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for (uint8_t i = 0; i < _output_buffer.get_length(); i++) {
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_output_buffer[i].quat_nominal = _state_reset_status.quat_change * _output_buffer[i].quat_nominal;
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}
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// apply the change in attitude quaternion to our newest quaternion estimate
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// which was already taken out from the output buffer
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_output_new.quat_nominal = _state_reset_status.quat_change * _output_new.quat_nominal;
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// capture the reset event
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_state_reset_status.quat_counter++;
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// flag the yaw as aligned
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_control_status.flags.yaw_align = true;
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// turn on fusion of external vision yaw measurements and disable all magnetometer fusion
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_control_status.flags.ev_yaw = true;
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_control_status.flags.mag_dec = false;
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stopMagHdgFusion();
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stopMag3DFusion();
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ECL_INFO_TIMESTAMPED("EKF commencing external vision yaw fusion");
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}
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}
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// determine if we should use the horizontal position observations
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if (_control_status.flags.ev_pos) {
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Vector3f ev_pos_obs_var{};
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Vector2f ev_pos_innov_gates{};
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// correct position and height for offset relative to IMU
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Vector3f pos_offset_body = _params.ev_pos_body - _params.imu_pos_body;
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Vector3f pos_offset_earth = _R_to_earth * pos_offset_body;
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_ev_sample_delayed.pos(0) -= pos_offset_earth(0);
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_ev_sample_delayed.pos(1) -= pos_offset_earth(1);
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_ev_sample_delayed.pos(2) -= pos_offset_earth(2);
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// Use an incremental position fusion method for EV position data if GPS is also used
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if (_params.fusion_mode & MASK_USE_GPS) {
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_fuse_hpos_as_odom = true;
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} else {
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_fuse_hpos_as_odom = false;
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}
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if (_fuse_hpos_as_odom) {
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if (!_hpos_prev_available) {
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// no previous observation available to calculate position change
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_fuse_pos = false;
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_hpos_prev_available = true;
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} else {
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// calculate the change in position since the last measurement
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Vector3f ev_delta_pos = _ev_sample_delayed.pos - _pos_meas_prev;
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// rotate measurement into body frame is required when fusing with GPS
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ev_delta_pos = _ev_rot_mat * ev_delta_pos;
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// use the change in position since the last measurement
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_ev_pos_innov(0) = _state.pos(0) - _hpos_pred_prev(0) - ev_delta_pos(0);
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_ev_pos_innov(1) = _state.pos(1) - _hpos_pred_prev(1) - ev_delta_pos(1);
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// observation 1-STD error, incremental pos observation is expected to have more uncertainty
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ev_pos_obs_var(0) = ev_pos_obs_var(1) = fmaxf(_ev_sample_delayed.posErr, 0.5f);
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}
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// record observation and estimate for use next time
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_pos_meas_prev = _ev_sample_delayed.pos;
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_hpos_pred_prev(0) = _state.pos(0);
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_hpos_pred_prev(1) = _state.pos(1);
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} else {
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// use the absolute position
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Vector3f ev_pos_meas = _ev_sample_delayed.pos;
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if (_params.fusion_mode & MASK_ROTATE_EV) {
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ev_pos_meas = _ev_rot_mat * ev_pos_meas;
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}
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_ev_pos_innov(0) = _state.pos(0) - ev_pos_meas(0);
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_ev_pos_innov(1) = _state.pos(1) - ev_pos_meas(1);
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// observation 1-STD error
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ev_pos_obs_var(0) = ev_pos_obs_var(1) = fmaxf(_ev_sample_delayed.posErr, 0.01f);
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// check if we have been deadreckoning too long
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if ((_time_last_imu - _time_last_hor_pos_fuse) > _params.reset_timeout_max) {
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// don't reset velocity if we have another source of aiding constraining it
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if (((_time_last_imu - _time_last_of_fuse) > (uint64_t)1E6) && ((_time_last_imu - _time_last_hor_vel_fuse) > (uint64_t)1E6)) {
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resetVelocity();
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}
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resetPosition();
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}
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}
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// innovation gate size
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ev_pos_innov_gates(0) = fmaxf(_params.ev_pos_innov_gate, 1.0f);
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fuseHorizontalPosition(_ev_pos_innov, ev_pos_innov_gates, ev_pos_obs_var, _ev_pos_innov_var, _ev_pos_test_ratio);
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}
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// determine if we should use the velocity observations
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if (_control_status.flags.ev_vel) {
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Vector3f ev_vel_obs_var{};
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Vector2f ev_vel_innov_gates{};
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Vector3f vel_aligned{_ev_sample_delayed.vel};
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// rotate measurement into correct earth frame if required
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if (_params.fusion_mode & MASK_ROTATE_EV) {
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vel_aligned = _ev_rot_mat * _ev_sample_delayed.vel;
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}
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// correct velocity for offset relative to IMU
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Vector3f ang_rate = _imu_sample_delayed.delta_ang * (1.0f / _imu_sample_delayed.delta_ang_dt);
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Vector3f pos_offset_body = _params.ev_pos_body - _params.imu_pos_body;
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Vector3f vel_offset_body = cross_product(ang_rate, pos_offset_body);
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Vector3f vel_offset_earth = _R_to_earth * vel_offset_body;
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vel_aligned -= vel_offset_earth;
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_ev_vel_innov(0) = _state.vel(0) - vel_aligned(0);
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_ev_vel_innov(1) = _state.vel(1) - vel_aligned(1);
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_ev_vel_innov(2) = _state.vel(2) - vel_aligned(2);
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// check if we have been deadreckoning too long
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if ((_time_last_imu - _time_last_hor_vel_fuse) > _params.reset_timeout_max) {
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// don't reset velocity if we have another source of aiding constraining it
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if (((_time_last_imu - _time_last_of_fuse) > (uint64_t)1E6) && ((_time_last_imu - _time_last_hor_pos_fuse) > (uint64_t)1E6)) {
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resetVelocity();
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}
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}
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// observation 1-STD error
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ev_vel_obs_var(0) = ev_vel_obs_var(1) = ev_vel_obs_var(2) = fmaxf(_ev_sample_delayed.velErr, 0.01f);
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// innovation gate size
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ev_vel_innov_gates(0) = ev_vel_innov_gates(1) = fmaxf(_params.ev_vel_innov_gate, 1.0f);
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fuseHorizontalVelocity(_ev_vel_innov, ev_vel_innov_gates,ev_vel_obs_var, _ev_vel_innov_var, _ev_vel_test_ratio);
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fuseVerticalVelocity(_ev_vel_innov, ev_vel_innov_gates, ev_vel_obs_var, _ev_vel_innov_var, _ev_vel_test_ratio);
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}
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// determine if we should use the yaw observation
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if (_control_status.flags.ev_yaw) {
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fuseHeading();
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}
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} else if ((_control_status.flags.ev_pos || _control_status.flags.ev_vel)
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&& (_time_last_imu >= _time_last_ext_vision)
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&& ((_time_last_imu - _time_last_ext_vision) > (uint64_t)_params.reset_timeout_max)) {
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// Turn off EV fusion mode if no data has been received
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stopEvFusion();
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ECL_INFO_TIMESTAMPED("EKF External Vision Data Stopped");
|
|
|
|
}
|
|
}
|
|
|
|
void Ekf::controlOpticalFlowFusion()
|
|
{
|
|
// Check if on ground motion is un-suitable for use of optical flow
|
|
if (!_control_status.flags.in_air) {
|
|
// When on ground check if the vehicle is being shaken or moved in a way that could cause a loss of navigation
|
|
const float accel_norm = _accel_vec_filt.norm();
|
|
|
|
const bool motion_is_excessive = ((accel_norm > (CONSTANTS_ONE_G * 1.5f)) // upper g limit
|
|
|| (accel_norm < (CONSTANTS_ONE_G * 0.5f)) // lower g limit
|
|
|| (_ang_rate_mag_filt > _flow_max_rate) // angular rate exceeds flow sensor limit
|
|
|| (_R_to_earth(2,2) < cosf(math::radians(30.0f)))); // tilted excessively
|
|
|
|
if (motion_is_excessive) {
|
|
_time_bad_motion_us = _imu_sample_delayed.time_us;
|
|
|
|
} else {
|
|
_time_good_motion_us = _imu_sample_delayed.time_us;
|
|
}
|
|
|
|
} else {
|
|
_time_bad_motion_us = 0;
|
|
_time_good_motion_us = _imu_sample_delayed.time_us;
|
|
}
|
|
|
|
// Accumulate autopilot gyro data across the same time interval as the flow sensor
|
|
_imu_del_ang_of += _imu_sample_delayed.delta_ang - _state.gyro_bias;
|
|
_delta_time_of += _imu_sample_delayed.delta_ang_dt;
|
|
|
|
// New optical flow data is available and is ready to be fused when the midpoint of the sample falls behind the fusion time horizon
|
|
if (_flow_data_ready) {
|
|
// Inhibit flow use if motion is un-suitable or we have good quality GPS
|
|
// Apply hysteresis to prevent rapid mode switching
|
|
float gps_err_norm_lim;
|
|
if (_control_status.flags.opt_flow) {
|
|
gps_err_norm_lim = 0.7f;
|
|
} else {
|
|
gps_err_norm_lim = 1.0f;
|
|
}
|
|
|
|
// Check if we are in-air and require optical flow to control position drift
|
|
bool flow_required = _control_status.flags.in_air &&
|
|
(_is_dead_reckoning // is doing inertial dead-reckoning so must constrain drift urgently
|
|
|| (_control_status.flags.opt_flow && !_control_status.flags.gps && !_control_status.flags.ev_pos && !_control_status.flags.ev_vel) // is completely reliant on optical flow
|
|
|| (_control_status.flags.gps && (_gps_error_norm > gps_err_norm_lim))); // is using GPS, but GPS is bad
|
|
|
|
if (!_inhibit_flow_use && _control_status.flags.opt_flow) {
|
|
// inhibit use of optical flow if motion is unsuitable and we are not reliant on it for flight navigation
|
|
bool preflight_motion_not_ok = !_control_status.flags.in_air && ((_imu_sample_delayed.time_us - _time_good_motion_us) > (uint64_t)1E5);
|
|
bool flight_motion_not_ok = _control_status.flags.in_air && !isRangeAidSuitable();
|
|
if ((preflight_motion_not_ok || flight_motion_not_ok) && !flow_required) {
|
|
_inhibit_flow_use = true;
|
|
}
|
|
} else if (_inhibit_flow_use && !_control_status.flags.opt_flow){
|
|
// allow use of optical flow if motion is suitable or we are reliant on it for flight navigation
|
|
bool preflight_motion_ok = !_control_status.flags.in_air && ((_imu_sample_delayed.time_us - _time_bad_motion_us) > (uint64_t)5E6);
|
|
bool flight_motion_ok = _control_status.flags.in_air && isRangeAidSuitable();
|
|
if (preflight_motion_ok || flight_motion_ok || flow_required) {
|
|
_inhibit_flow_use = false;
|
|
}
|
|
}
|
|
|
|
// Handle cases where we are using optical flow but are no longer able to because data is old
|
|
// or its use has been inhibited.
|
|
if (_control_status.flags.opt_flow) {
|
|
if (_inhibit_flow_use) {
|
|
stopFlowFusion();
|
|
_time_last_of_fuse = 0;
|
|
|
|
} else if ((_time_last_imu - _time_last_of_fuse) > (uint64_t)_params.reset_timeout_max) {
|
|
stopFlowFusion();
|
|
|
|
}
|
|
}
|
|
|
|
// optical flow fusion mode selection logic
|
|
if ((_params.fusion_mode & MASK_USE_OF) // optical flow has been selected by the user
|
|
&& !_control_status.flags.opt_flow // we are not yet using flow data
|
|
&& _control_status.flags.tilt_align // we know our tilt attitude
|
|
&& !_inhibit_flow_use
|
|
&& isTerrainEstimateValid())
|
|
{
|
|
// If the heading is not aligned, reset the yaw and magnetic field states
|
|
if (!_control_status.flags.yaw_align) {
|
|
_control_status.flags.yaw_align = resetMagHeading(_mag_lpf.getState());
|
|
}
|
|
|
|
// If the heading is valid and use is not inhibited , start using optical flow aiding
|
|
if (_control_status.flags.yaw_align) {
|
|
// set the flag and reset the fusion timeout
|
|
_control_status.flags.opt_flow = true;
|
|
_time_last_of_fuse = _time_last_imu;
|
|
|
|
// if we are not using GPS or external vision aiding, then the velocity and position states and covariances need to be set
|
|
const bool flow_aid_only = !(_control_status.flags.gps || _control_status.flags.ev_pos || _control_status.flags.ev_vel);
|
|
if (flow_aid_only) {
|
|
resetVelocity();
|
|
resetPosition();
|
|
|
|
// align the output observer to the EKF states
|
|
alignOutputFilter();
|
|
}
|
|
}
|
|
|
|
} else if (!(_params.fusion_mode & MASK_USE_OF)) {
|
|
_control_status.flags.opt_flow = false;
|
|
}
|
|
|
|
// handle the case when we have optical flow, are reliant on it, but have not been using it for an extended period
|
|
if (_control_status.flags.opt_flow
|
|
&& !_control_status.flags.gps
|
|
&& !_control_status.flags.ev_pos
|
|
&& !_control_status.flags.ev_vel) {
|
|
|
|
bool do_reset = ((_time_last_imu - _time_last_of_fuse) > _params.reset_timeout_max);
|
|
|
|
if (do_reset) {
|
|
resetVelocity();
|
|
resetPosition();
|
|
}
|
|
}
|
|
|
|
// Only fuse optical flow if valid body rate compensation data is available
|
|
if (calcOptFlowBodyRateComp()) {
|
|
|
|
bool flow_quality_good = (_flow_sample_delayed.quality >= _params.flow_qual_min);
|
|
|
|
if (!flow_quality_good && !_control_status.flags.in_air) {
|
|
// when on the ground with poor flow quality, assume zero ground relative velocity and LOS rate
|
|
_flowRadXYcomp.zero();
|
|
} else {
|
|
// compensate for body motion to give a LOS rate
|
|
_flowRadXYcomp(0) = _flow_sample_delayed.flowRadXY(0) - _flow_sample_delayed.gyroXYZ(0);
|
|
_flowRadXYcomp(1) = _flow_sample_delayed.flowRadXY(1) - _flow_sample_delayed.gyroXYZ(1);
|
|
}
|
|
} else {
|
|
// don't use this flow data and wait for the next data to arrive
|
|
_flow_data_ready = false;
|
|
}
|
|
}
|
|
|
|
// Wait until the midpoint of the flow sample has fallen behind the fusion time horizon
|
|
if (_flow_data_ready && (_imu_sample_delayed.time_us > _flow_sample_delayed.time_us - uint32_t(1e6f * _flow_sample_delayed.dt) / 2)) {
|
|
// Fuse optical flow LOS rate observations into the main filter only if height above ground has been updated recently
|
|
// but use a relaxed time criteria to enable it to coast through bad range finder data
|
|
if (_control_status.flags.opt_flow && ((_time_last_imu - _time_last_hagl_fuse) < (uint64_t)10e6)) {
|
|
fuseOptFlow();
|
|
_last_known_posNE(0) = _state.pos(0);
|
|
_last_known_posNE(1) = _state.pos(1);
|
|
}
|
|
|
|
_flow_data_ready = false;
|
|
}
|
|
}
|
|
|
|
void Ekf::controlGpsFusion()
|
|
{
|
|
// Check for new GPS data that has fallen behind the fusion time horizon
|
|
if (_gps_data_ready) {
|
|
|
|
// GPS yaw aiding selection logic
|
|
if ((_params.fusion_mode & MASK_USE_GPSYAW)
|
|
&& ISFINITE(_gps_sample_delayed.yaw)
|
|
&& _control_status.flags.tilt_align
|
|
&& (!_control_status.flags.gps_yaw || !_control_status.flags.yaw_align)
|
|
&& ((_time_last_imu - _time_last_gps) < (2 * GPS_MAX_INTERVAL))) {
|
|
|
|
if (resetGpsAntYaw()) {
|
|
// flag the yaw as aligned
|
|
_control_status.flags.yaw_align = true;
|
|
|
|
// turn on fusion of external vision yaw measurements and disable all other yaw fusion
|
|
_control_status.flags.gps_yaw = true;
|
|
_control_status.flags.ev_yaw = false;
|
|
_control_status.flags.mag_dec = false;
|
|
|
|
stopMagHdgFusion();
|
|
stopMag3DFusion();
|
|
|
|
ECL_INFO_TIMESTAMPED("EKF commencing GPS yaw fusion");
|
|
}
|
|
}
|
|
|
|
// fuse the yaw observation
|
|
if (_control_status.flags.gps_yaw) {
|
|
fuseGpsAntYaw();
|
|
}
|
|
|
|
// Determine if we should use GPS aiding for velocity and horizontal position
|
|
// To start using GPS we need angular alignment completed, the local NED origin set and GPS data that has not failed checks recently
|
|
bool gps_checks_passing = (_time_last_imu - _last_gps_fail_us > (uint64_t)5e6);
|
|
bool gps_checks_failing = (_time_last_imu - _last_gps_pass_us > (uint64_t)5e6);
|
|
if ((_params.fusion_mode & MASK_USE_GPS) && !_control_status.flags.gps) {
|
|
if (_control_status.flags.tilt_align && _NED_origin_initialised && gps_checks_passing) {
|
|
// If the heading is not aligned, reset the yaw and magnetic field states
|
|
// Do not use external vision for yaw if using GPS because yaw needs to be
|
|
// defined relative to an NED reference frame
|
|
const bool want_to_reset_mag_heading = !_control_status.flags.yaw_align ||
|
|
_control_status.flags.ev_yaw ||
|
|
_mag_inhibit_yaw_reset_req;
|
|
if (want_to_reset_mag_heading && canResetMagHeading()) {
|
|
_control_status.flags.ev_yaw = false;
|
|
_control_status.flags.yaw_align = resetMagHeading(_mag_lpf.getState());
|
|
// Handle the special case where we have not been constraining yaw drift or learning yaw bias due
|
|
// to assumed invalid mag field associated with indoor operation with a downwards looking flow sensor.
|
|
if (_mag_inhibit_yaw_reset_req) {
|
|
_mag_inhibit_yaw_reset_req = false;
|
|
// Zero the yaw bias covariance and set the variance to the initial alignment uncertainty
|
|
setDiag(P, 12, 12, sq(_params.switch_on_gyro_bias * FILTER_UPDATE_PERIOD_S));
|
|
}
|
|
}
|
|
|
|
// If the heading is valid start using gps aiding
|
|
if (_control_status.flags.yaw_align) {
|
|
// if we are not already aiding with optical flow, then we need to reset the position and velocity
|
|
// otherwise we only need to reset the position
|
|
_control_status.flags.gps = true;
|
|
|
|
if (!_control_status.flags.opt_flow) {
|
|
if (!resetPosition() || !resetVelocity()) {
|
|
_control_status.flags.gps = false;
|
|
|
|
}
|
|
|
|
} else if (!resetPosition()) {
|
|
_control_status.flags.gps = false;
|
|
|
|
}
|
|
|
|
if (_control_status.flags.gps) {
|
|
ECL_INFO_TIMESTAMPED("EKF commencing GPS fusion");
|
|
_time_last_gps = _time_last_imu;
|
|
}
|
|
}
|
|
}
|
|
|
|
} else if (!(_params.fusion_mode & MASK_USE_GPS)) {
|
|
_control_status.flags.gps = false;
|
|
|
|
}
|
|
|
|
// Handle the case where we are using GPS and another source of aiding and GPS is failing checks
|
|
if (_control_status.flags.gps && gps_checks_failing && (_control_status.flags.opt_flow || _control_status.flags.ev_pos || _control_status.flags.ev_vel)) {
|
|
stopGpsFusion();
|
|
// Reset position state to external vision if we are going to use absolute values
|
|
if (_control_status.flags.ev_pos && !(_params.fusion_mode & MASK_ROTATE_EV)) {
|
|
resetPosition();
|
|
}
|
|
ECL_WARN_TIMESTAMPED("EKF GPS data quality poor - stopping use");
|
|
}
|
|
|
|
// handle the case when we now have GPS, but have not been using it for an extended period
|
|
if (_control_status.flags.gps) {
|
|
// We are relying on aiding to constrain drift so after a specified time
|
|
// with no aiding we need to do something
|
|
bool do_reset = ((_time_last_imu - _time_last_hor_pos_fuse) > _params.reset_timeout_max)
|
|
&& ((_time_last_imu - _time_last_delpos_fuse) > _params.reset_timeout_max)
|
|
&& ((_time_last_imu - _time_last_hor_vel_fuse) > _params.reset_timeout_max)
|
|
&& ((_time_last_imu - _time_last_of_fuse) > _params.reset_timeout_max);
|
|
|
|
// We haven't had an absolute position fix for a longer time so need to do something
|
|
do_reset = do_reset || ((_time_last_imu - _time_last_hor_pos_fuse) > (2 * _params.reset_timeout_max));
|
|
|
|
if (do_reset) {
|
|
// use GPS velocity data to check and correct yaw angle if a FW vehicle
|
|
if (_control_status.flags.fixed_wing && _control_status.flags.in_air) {
|
|
// if flying a fixed wing aircraft, do a complete reset that includes yaw
|
|
_control_status.flags.mag_aligned_in_flight = realignYawGPS();
|
|
}
|
|
|
|
resetVelocity();
|
|
resetPosition();
|
|
_velpos_reset_request = false;
|
|
ECL_WARN_TIMESTAMPED("EKF GPS fusion timeout - reset to GPS");
|
|
|
|
// Reset the timeout counters
|
|
_time_last_hor_pos_fuse = _time_last_imu;
|
|
_time_last_hor_vel_fuse = _time_last_imu;
|
|
|
|
}
|
|
}
|
|
|
|
// Only use GPS data for position and velocity aiding if enabled
|
|
if (_control_status.flags.gps) {
|
|
|
|
|
|
Vector2f gps_vel_innov_gates{}; // [horizontal vertical]
|
|
Vector2f gps_pos_innov_gates{}; // [horizontal vertical]
|
|
Vector3f gps_vel_obs_var{};
|
|
Vector3f gps_pos_obs_var{};
|
|
|
|
// correct velocity for offset relative to IMU
|
|
Vector3f ang_rate = _imu_sample_delayed.delta_ang * (1.0f / _imu_sample_delayed.delta_ang_dt);
|
|
Vector3f pos_offset_body = _params.gps_pos_body - _params.imu_pos_body;
|
|
Vector3f vel_offset_body = cross_product(ang_rate, pos_offset_body);
|
|
Vector3f vel_offset_earth = _R_to_earth * vel_offset_body;
|
|
_gps_sample_delayed.vel -= vel_offset_earth;
|
|
|
|
// correct position and height for offset relative to IMU
|
|
Vector3f pos_offset_earth = _R_to_earth * pos_offset_body;
|
|
_gps_sample_delayed.pos(0) -= pos_offset_earth(0);
|
|
_gps_sample_delayed.pos(1) -= pos_offset_earth(1);
|
|
_gps_sample_delayed.hgt += pos_offset_earth(2);
|
|
|
|
// calculate observation process noise
|
|
float lower_limit = fmaxf(_params.gps_pos_noise, 0.01f);
|
|
|
|
if (_control_status.flags.opt_flow || _control_status.flags.ev_pos || _control_status.flags.ev_vel) {
|
|
// if we are using other sources of aiding, then relax the upper observation
|
|
// noise limit which prevents bad GPS perturbing the position estimate
|
|
gps_pos_obs_var(0) = gps_pos_obs_var(1) = fmaxf(_gps_sample_delayed.hacc, lower_limit);
|
|
|
|
} else {
|
|
// if we are not using another source of aiding, then we are reliant on the GPS
|
|
// observations to constrain attitude errors and must limit the observation noise value.
|
|
float upper_limit = fmaxf(_params.pos_noaid_noise, lower_limit);
|
|
gps_pos_obs_var(0) = gps_pos_obs_var(1) = math::constrain(_gps_sample_delayed.hacc, lower_limit, upper_limit);
|
|
}
|
|
|
|
gps_vel_obs_var(0) = gps_vel_obs_var(1) = gps_vel_obs_var(2) = sq(fmaxf(_gps_sample_delayed.sacc, _params.gps_vel_noise));
|
|
|
|
// calculate innovations
|
|
_gps_vel_innov(0) = _state.vel(0) - _gps_sample_delayed.vel(0);
|
|
_gps_vel_innov(1) = _state.vel(1) - _gps_sample_delayed.vel(1);
|
|
_gps_vel_innov(2) = _state.vel(2) - _gps_sample_delayed.vel(2);
|
|
_gps_pos_innov(0) = _state.pos(0) - _gps_sample_delayed.pos(0);
|
|
_gps_pos_innov(1) = _state.pos(1) - _gps_sample_delayed.pos(1);
|
|
|
|
// set innovation gate size
|
|
gps_pos_innov_gates(0) = fmaxf(_params.gps_pos_innov_gate, 1.0f);
|
|
gps_pos_innov_gates(1) = fmaxf(_params.gps_vel_innov_gate, 1.0f);
|
|
|
|
// fuse GPS measurement
|
|
fuseHorizontalVelocity(_gps_vel_innov, gps_vel_innov_gates,gps_vel_obs_var, _gps_vel_innov_var, _gps_vel_test_ratio);
|
|
fuseVerticalVelocity(_gps_vel_innov, gps_vel_innov_gates, gps_vel_obs_var, _gps_vel_innov_var, _gps_vel_test_ratio);
|
|
fuseHorizontalPosition(_gps_pos_innov, gps_pos_innov_gates, gps_pos_obs_var, _gps_pos_innov_var, _gps_pos_test_ratio);
|
|
}
|
|
|
|
} else if (_control_status.flags.gps && (_imu_sample_delayed.time_us - _gps_sample_delayed.time_us > (uint64_t)10e6)) {
|
|
stopGpsFusion();
|
|
ECL_WARN_TIMESTAMPED("EKF GPS data stopped");
|
|
} else if (_control_status.flags.gps && (_imu_sample_delayed.time_us - _gps_sample_delayed.time_us > (uint64_t)1e6) && (_control_status.flags.opt_flow || _control_status.flags.ev_pos || _control_status.flags.ev_vel)) {
|
|
// Handle the case where we are fusing another position source along GPS,
|
|
// stop waiting for GPS after 1 s of lost signal
|
|
stopGpsFusion();
|
|
ECL_WARN_TIMESTAMPED("EKF GPS data stopped, using only EV or OF");
|
|
}
|
|
}
|
|
|
|
void Ekf::controlHeightSensorTimeouts()
|
|
{
|
|
/*
|
|
* Handle the case where we have not fused height measurements recently and
|
|
* uncertainty exceeds the max allowable. Reset using the best available height
|
|
* measurement source, continue using it after the reset and declare the current
|
|
* source failed if we have switched.
|
|
*/
|
|
|
|
// Check for IMU accelerometer vibration induced clipping as evidenced by the vertical innovations being positive and not stale.
|
|
// Clipping causes the average accel reading to move towards zero which makes the INS think it is falling and produces positive vertical innovations
|
|
float var_product_lim = sq(_params.vert_innov_test_lim) * sq(_params.vert_innov_test_lim);
|
|
bool bad_vert_accel = (_control_status.flags.baro_hgt && // we can only run this check if vertical position and velocity observations are independent
|
|
(sq(_gps_pos_innov(2) * fmaxf(fabsf(_gps_vel_innov(2)),fabsf(_ev_vel_innov(2)))) > var_product_lim * (_gps_pos_innov_var(2) * fmaxf(fabsf(_gps_vel_innov_var(2)),fabsf(_ev_vel_innov_var(2))))) && // vertical position and velocity sensors are in agreement that we have a significant error
|
|
(_gps_vel_innov(2) > 0.0f || _ev_vel_innov(2) > 0.0f) && // positive innovation indicates that the inertial nav thinks it is falling
|
|
((_imu_sample_delayed.time_us - _baro_sample_delayed.time_us) < 2 * BARO_MAX_INTERVAL) && // vertical position data is fresh
|
|
((_imu_sample_delayed.time_us - _gps_sample_delayed.time_us) < 2 * GPS_MAX_INTERVAL)); // vertical velocity data is fresh
|
|
|
|
// record time of last bad vert accel
|
|
if (bad_vert_accel) {
|
|
_time_bad_vert_accel = _time_last_imu;
|
|
|
|
} else {
|
|
_time_good_vert_accel = _time_last_imu;
|
|
}
|
|
|
|
// declare a bad vertical acceleration measurement and make the declaration persist
|
|
// for a minimum of 10 seconds
|
|
if (_bad_vert_accel_detected) {
|
|
_bad_vert_accel_detected = (_time_last_imu - _time_bad_vert_accel < BADACC_PROBATION);
|
|
|
|
} else {
|
|
_bad_vert_accel_detected = bad_vert_accel;
|
|
}
|
|
|
|
// check if height is continuously failing because of accel errors
|
|
bool continuous_bad_accel_hgt = ((_time_last_imu - _time_good_vert_accel) > (unsigned)_params.bad_acc_reset_delay_us);
|
|
|
|
// check if height has been inertial deadreckoning for too long
|
|
bool hgt_fusion_timeout = ((_time_last_imu - _time_last_hgt_fuse) > (uint64_t)5e6);
|
|
|
|
// reset the vertical position and velocity states
|
|
if (hgt_fusion_timeout || continuous_bad_accel_hgt) {
|
|
// boolean that indicates we will do a height reset
|
|
bool reset_height = false;
|
|
|
|
// handle the case where we are using baro for height
|
|
if (_control_status.flags.baro_hgt) {
|
|
// check if GPS height is available
|
|
const gpsSample &gps_init = _gps_buffer.get_newest();
|
|
bool gps_hgt_accurate = (gps_init.vacc < _params.req_vacc);
|
|
|
|
const baroSample &baro_init = _baro_buffer.get_newest();
|
|
bool baro_hgt_available = ((_time_last_imu - baro_init.time_us) < 2 * BARO_MAX_INTERVAL);
|
|
|
|
// check for inertial sensing errors in the last 10 seconds
|
|
bool prev_bad_vert_accel = (_time_last_imu - _time_bad_vert_accel < BADACC_PROBATION);
|
|
|
|
// reset to GPS if adequate GPS data is available and the timeout cannot be blamed on IMU data
|
|
bool reset_to_gps = !_gps_hgt_intermittent && gps_hgt_accurate && !prev_bad_vert_accel;
|
|
|
|
// reset to GPS if GPS data is available and there is no Baro data
|
|
reset_to_gps = reset_to_gps || (!_gps_hgt_intermittent && !baro_hgt_available);
|
|
|
|
// reset to Baro if we are not doing a GPS reset and baro data is available
|
|
bool reset_to_baro = !reset_to_gps && baro_hgt_available;
|
|
|
|
if (reset_to_gps) {
|
|
// set height sensor health
|
|
_baro_hgt_faulty = true;
|
|
|
|
// reset the height mode
|
|
setControlGPSHeight();
|
|
|
|
// request a reset
|
|
reset_height = true;
|
|
ECL_WARN_TIMESTAMPED("EKF baro hgt timeout - reset to GPS");
|
|
|
|
} else if (reset_to_baro) {
|
|
// set height sensor health
|
|
_baro_hgt_faulty = false;
|
|
|
|
// reset the height mode
|
|
setControlBaroHeight();
|
|
|
|
// request a reset
|
|
reset_height = true;
|
|
ECL_WARN_TIMESTAMPED("EKF baro hgt timeout - reset to baro");
|
|
|
|
} else {
|
|
// we have nothing we can reset to
|
|
// deny a reset
|
|
reset_height = false;
|
|
|
|
}
|
|
}
|
|
|
|
// handle the case we are using GPS for height
|
|
if (_control_status.flags.gps_hgt) {
|
|
// check if GPS height is available
|
|
const gpsSample &gps_init = _gps_buffer.get_newest();
|
|
bool gps_hgt_accurate = (gps_init.vacc < _params.req_vacc);
|
|
|
|
// check the baro height source for consistency and freshness
|
|
const baroSample &baro_init = _baro_buffer.get_newest();
|
|
bool baro_data_fresh = ((_time_last_imu - baro_init.time_us) < 2 * BARO_MAX_INTERVAL);
|
|
float baro_innov = _state.pos(2) - (_hgt_sensor_offset - baro_init.hgt + _baro_hgt_offset);
|
|
bool baro_data_consistent = fabsf(baro_innov) < (sq(_params.baro_noise) + P[9][9]) * sq(_params.baro_innov_gate);
|
|
|
|
// if baro data is acceptable and GPS data is inaccurate, reset height to baro
|
|
bool reset_to_baro = baro_data_consistent && baro_data_fresh && !_baro_hgt_faulty && !gps_hgt_accurate;
|
|
|
|
// if GPS height is unavailable and baro data is available, reset height to baro
|
|
reset_to_baro = reset_to_baro || (_gps_hgt_intermittent && baro_data_fresh);
|
|
|
|
// if we cannot switch to baro and GPS data is available, reset height to GPS
|
|
bool reset_to_gps = !reset_to_baro && !_gps_hgt_intermittent;
|
|
|
|
if (reset_to_baro) {
|
|
// set height sensor health
|
|
_baro_hgt_faulty = false;
|
|
|
|
// reset the height mode
|
|
setControlBaroHeight();
|
|
|
|
// request a reset
|
|
reset_height = true;
|
|
ECL_WARN_TIMESTAMPED("EKF gps hgt timeout - reset to baro");
|
|
|
|
} else if (reset_to_gps) {
|
|
// reset the height mode
|
|
setControlGPSHeight();
|
|
|
|
// request a reset
|
|
reset_height = true;
|
|
ECL_WARN_TIMESTAMPED("EKF gps hgt timeout - reset to GPS");
|
|
|
|
} else {
|
|
// we have nothing to reset to
|
|
reset_height = false;
|
|
|
|
}
|
|
}
|
|
|
|
// handle the case we are using range finder for height
|
|
if (_control_status.flags.rng_hgt) {
|
|
|
|
// check if baro data is available
|
|
const baroSample &baro_init = _baro_buffer.get_newest();
|
|
bool baro_data_available = ((_time_last_imu - baro_init.time_us) < 2 * BARO_MAX_INTERVAL);
|
|
|
|
// reset to baro if we have no range data and baro data is available
|
|
bool reset_to_baro = !_rng_hgt_valid && baro_data_available;
|
|
|
|
if (_rng_hgt_valid) {
|
|
|
|
// reset the height mode
|
|
setControlRangeHeight();
|
|
|
|
// request a reset
|
|
reset_height = true;
|
|
ECL_WARN_TIMESTAMPED("EKF rng hgt timeout - reset to rng hgt");
|
|
|
|
} else if (reset_to_baro) {
|
|
// set height sensor health
|
|
_baro_hgt_faulty = false;
|
|
|
|
// reset the height mode
|
|
setControlBaroHeight();
|
|
|
|
// request a reset
|
|
reset_height = true;
|
|
ECL_WARN_TIMESTAMPED("EKF rng hgt timeout - reset to baro");
|
|
|
|
} else {
|
|
// we have nothing to reset to
|
|
reset_height = false;
|
|
|
|
}
|
|
}
|
|
|
|
// handle the case where we are using external vision data for height
|
|
if (_control_status.flags.ev_hgt) {
|
|
// check if vision data is available
|
|
const extVisionSample &ev_init = _ext_vision_buffer.get_newest();
|
|
bool ev_data_available = ((_time_last_imu - ev_init.time_us) < 2 * EV_MAX_INTERVAL);
|
|
|
|
// check if baro data is available
|
|
const baroSample &baro_init = _baro_buffer.get_newest();
|
|
bool baro_data_available = ((_time_last_imu - baro_init.time_us) < 2 * BARO_MAX_INTERVAL);
|
|
|
|
// reset to baro if we have no vision data and baro data is available
|
|
bool reset_to_baro = !ev_data_available && baro_data_available;
|
|
|
|
// reset to ev data if it is available
|
|
bool reset_to_ev = ev_data_available;
|
|
|
|
if (reset_to_baro) {
|
|
// set height sensor health
|
|
_baro_hgt_faulty = false;
|
|
|
|
// reset the height mode
|
|
setControlBaroHeight();
|
|
|
|
// request a reset
|
|
reset_height = true;
|
|
ECL_WARN_TIMESTAMPED("EKF ev hgt timeout - reset to baro");
|
|
|
|
} else if (reset_to_ev) {
|
|
// reset the height mode
|
|
setControlEVHeight();
|
|
|
|
// request a reset
|
|
reset_height = true;
|
|
ECL_WARN_TIMESTAMPED("EKF ev hgt timeout - reset to ev hgt");
|
|
|
|
} else {
|
|
// we have nothing to reset to
|
|
reset_height = false;
|
|
|
|
}
|
|
}
|
|
|
|
// Reset vertical position and velocity states to the last measurement
|
|
if (reset_height) {
|
|
resetHeight();
|
|
// Reset the timout timer
|
|
_time_last_hgt_fuse = _time_last_imu;
|
|
|
|
}
|
|
|
|
}
|
|
}
|
|
|
|
void Ekf::controlHeightFusion()
|
|
{
|
|
|
|
checkRangeAidSuitability();
|
|
_range_aid_mode_selected = (_params.range_aid == 1) && isRangeAidSuitable();
|
|
|
|
if (_params.vdist_sensor_type == VDIST_SENSOR_BARO) {
|
|
|
|
if (_range_aid_mode_selected && _range_data_ready && _rng_hgt_valid) {
|
|
setControlRangeHeight();
|
|
_fuse_height = true;
|
|
|
|
// we have just switched to using range finder, calculate height sensor offset such that current
|
|
// measurement matches our current height estimate
|
|
if (_control_status_prev.flags.rng_hgt != _control_status.flags.rng_hgt) {
|
|
if (isTerrainEstimateValid()) {
|
|
_hgt_sensor_offset = _terrain_vpos;
|
|
|
|
} else {
|
|
_hgt_sensor_offset = _R_rng_to_earth_2_2 * _range_sample_delayed.rng + _state.pos(2);
|
|
}
|
|
}
|
|
|
|
} else if (!_range_aid_mode_selected && _baro_data_ready && !_baro_hgt_faulty) {
|
|
setControlBaroHeight();
|
|
_fuse_height = true;
|
|
|
|
// we have just switched to using baro height, we don't need to set a height sensor offset
|
|
// since we track a separate _baro_hgt_offset
|
|
if (_control_status_prev.flags.baro_hgt != _control_status.flags.baro_hgt) {
|
|
_hgt_sensor_offset = 0.0f;
|
|
}
|
|
|
|
// Turn off ground effect compensation if it times out
|
|
if (_control_status.flags.gnd_effect) {
|
|
if ((_time_last_imu - _time_last_gnd_effect_on > GNDEFFECT_TIMEOUT)) {
|
|
|
|
_control_status.flags.gnd_effect = false;
|
|
}
|
|
}
|
|
|
|
} else if (_control_status.flags.gps_hgt && _gps_data_ready && !_gps_hgt_intermittent) {
|
|
// switch to gps if there was a reset to gps
|
|
_fuse_height = true;
|
|
|
|
// we have just switched to using gps height, calculate height sensor offset such that current
|
|
// measurement matches our current height estimate
|
|
if (_control_status_prev.flags.gps_hgt != _control_status.flags.gps_hgt) {
|
|
_hgt_sensor_offset = _gps_sample_delayed.hgt - _gps_alt_ref + _state.pos(2);
|
|
}
|
|
}
|
|
}
|
|
|
|
// set the height data source to range if requested
|
|
if ((_params.vdist_sensor_type == VDIST_SENSOR_RANGE) && _rng_hgt_valid) {
|
|
setControlRangeHeight();
|
|
_fuse_height = _range_data_ready;
|
|
|
|
// we have just switched to using range finder, calculate height sensor offset such that current
|
|
// measurement matches our current height estimate
|
|
if (_control_status_prev.flags.rng_hgt != _control_status.flags.rng_hgt) {
|
|
// use the parameter rng_gnd_clearance if on ground to avoid a noisy offset initialization (e.g. sonar)
|
|
if (_control_status.flags.in_air && isTerrainEstimateValid()) {
|
|
|
|
_hgt_sensor_offset = _terrain_vpos;
|
|
|
|
} else if (_control_status.flags.in_air) {
|
|
|
|
_hgt_sensor_offset = _R_rng_to_earth_2_2 * _range_sample_delayed.rng + _state.pos(2);
|
|
|
|
} else {
|
|
|
|
_hgt_sensor_offset = _params.rng_gnd_clearance;
|
|
}
|
|
}
|
|
|
|
} else if ((_params.vdist_sensor_type == VDIST_SENSOR_RANGE) && _baro_data_ready && !_baro_hgt_faulty) {
|
|
setControlBaroHeight();
|
|
_fuse_height = true;
|
|
|
|
// we have just switched to using baro height, we don't need to set a height sensor offset
|
|
// since we track a separate _baro_hgt_offset
|
|
if (_control_status_prev.flags.baro_hgt != _control_status.flags.baro_hgt) {
|
|
_hgt_sensor_offset = 0.0f;
|
|
}
|
|
}
|
|
|
|
// Determine if GPS should be used as the height source
|
|
if (_params.vdist_sensor_type == VDIST_SENSOR_GPS) {
|
|
|
|
if (_range_aid_mode_selected && _range_data_ready && _rng_hgt_valid) {
|
|
setControlRangeHeight();
|
|
_fuse_height = true;
|
|
|
|
// we have just switched to using range finder, calculate height sensor offset such that current
|
|
// measurement matches our current height estimate
|
|
if (_control_status_prev.flags.rng_hgt != _control_status.flags.rng_hgt) {
|
|
if (isTerrainEstimateValid()) {
|
|
_hgt_sensor_offset = _terrain_vpos;
|
|
|
|
} else {
|
|
_hgt_sensor_offset = _R_rng_to_earth_2_2 * _range_sample_delayed.rng + _state.pos(2);
|
|
}
|
|
}
|
|
|
|
} else if (!_range_aid_mode_selected && _gps_data_ready && !_gps_hgt_intermittent && _gps_checks_passed) {
|
|
setControlGPSHeight();
|
|
_fuse_height = true;
|
|
|
|
// we have just switched to using gps height, calculate height sensor offset such that current
|
|
// measurement matches our current height estimate
|
|
if (_control_status_prev.flags.gps_hgt != _control_status.flags.gps_hgt) {
|
|
_hgt_sensor_offset = _gps_sample_delayed.hgt - _gps_alt_ref + _state.pos(2);
|
|
}
|
|
|
|
} else if (_control_status.flags.baro_hgt && _baro_data_ready && !_baro_hgt_faulty) {
|
|
// switch to baro if there was a reset to baro
|
|
_fuse_height = true;
|
|
|
|
// we have just switched to using baro height, we don't need to set a height sensor offset
|
|
// since we track a separate _baro_hgt_offset
|
|
if (_control_status_prev.flags.baro_hgt != _control_status.flags.baro_hgt) {
|
|
_hgt_sensor_offset = 0.0f;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Determine if we rely on EV height but switched to baro
|
|
if (_params.vdist_sensor_type == VDIST_SENSOR_EV) {
|
|
|
|
// don't start using EV data unless data is arriving frequently
|
|
if (!_control_status.flags.ev_hgt && ((_time_last_imu - _time_last_ext_vision) < (2 * EV_MAX_INTERVAL))) {
|
|
_fuse_height = true;
|
|
setControlEVHeight();
|
|
resetHeight();
|
|
}
|
|
|
|
if (_control_status.flags.baro_hgt && _baro_data_ready && !_baro_hgt_faulty) {
|
|
// switch to baro if there was a reset to baro
|
|
_fuse_height = true;
|
|
|
|
// we have just switched to using baro height, we don't need to set a height sensor offset
|
|
// since we track a separate _baro_hgt_offset
|
|
if (_control_status_prev.flags.baro_hgt != _control_status.flags.baro_hgt) {
|
|
_hgt_sensor_offset = 0.0f;
|
|
}
|
|
}
|
|
// TODO: Add EV normal case here
|
|
// determine if we should use the vertical position observation
|
|
if (_control_status.flags.ev_hgt) {
|
|
_fuse_height = true;
|
|
}
|
|
}
|
|
|
|
// calculate a filtered offset between the baro origin and local NED origin if we are not using the baro as a height reference
|
|
if (!_control_status.flags.baro_hgt && _baro_data_ready) {
|
|
float local_time_step = 1e-6f * _delta_time_baro_us;
|
|
local_time_step = math::constrain(local_time_step, 0.0f, 1.0f);
|
|
|
|
// apply a 10 second first order low pass filter to baro offset
|
|
float offset_rate_correction = 0.1f * (_baro_sample_delayed.hgt + _state.pos(
|
|
2) - _baro_hgt_offset);
|
|
_baro_hgt_offset += local_time_step * math::constrain(offset_rate_correction, -0.1f, 0.1f);
|
|
}
|
|
|
|
if ((_time_last_imu - _time_last_hgt_fuse) > 2 * RNG_MAX_INTERVAL && _control_status.flags.rng_hgt
|
|
&& (!_range_data_ready || !_rng_hgt_valid)) {
|
|
|
|
// If we are supposed to be using range finder data as the primary height sensor, have missed or rejected measurements
|
|
// and are on the ground, then synthesise a measurement at the expected on ground value
|
|
if (!_control_status.flags.in_air) {
|
|
_range_sample_delayed.rng = _params.rng_gnd_clearance;
|
|
_range_sample_delayed.time_us = _imu_sample_delayed.time_us;
|
|
|
|
}
|
|
|
|
_fuse_height = true;
|
|
}
|
|
|
|
if (_fuse_height) {
|
|
|
|
Vector2f height_innov_gate{};
|
|
Vector2f height_test_ratio{};
|
|
Vector3f height_obs_var{};
|
|
Vector3f height_innov_var{};
|
|
Vector3f height_innov{};
|
|
|
|
if (_control_status.flags.baro_hgt) {
|
|
// vertical position innovation - baro measurement has opposite sign to earth z axis
|
|
height_innov(2) = _state.pos(2) + _baro_sample_delayed.hgt - _baro_hgt_offset - _hgt_sensor_offset;
|
|
// observation variance - user parameter defined
|
|
height_obs_var(2) = sq(fmaxf(_params.baro_noise, 0.01f));
|
|
|
|
// innovation gate size
|
|
height_innov_gate(1) = fmaxf(_params.baro_innov_gate, 1.0f);
|
|
|
|
// Compensate for positive static pressure transients (negative vertical position innovations)
|
|
// caused by rotor wash ground interaction by applying a temporary deadzone to baro innovations.
|
|
float deadzone_start = 0.0f;
|
|
float deadzone_end = deadzone_start + _params.gnd_effect_deadzone;
|
|
|
|
if (_control_status.flags.gnd_effect) {
|
|
if (height_innov(2) < -deadzone_start) {
|
|
if (height_innov(2) <= -deadzone_end) {
|
|
height_innov(2) += deadzone_end;
|
|
|
|
} else {
|
|
height_innov(2) = -deadzone_start;
|
|
}
|
|
}
|
|
}
|
|
|
|
} else if (_control_status.flags.gps_hgt) {
|
|
// vertical position innovation - gps measurement has opposite sign to earth z axis
|
|
height_innov(2) = _state.pos(2) + _gps_sample_delayed.hgt - _gps_alt_ref - _hgt_sensor_offset;
|
|
// observation variance - receiver defined and parameter limited
|
|
// use scaled horizontal position accuracy assuming typical ratio of VDOP/HDOP
|
|
float lower_limit = fmaxf(_params.gps_pos_noise, 0.01f);
|
|
float upper_limit = fmaxf(_params.pos_noaid_noise, lower_limit);
|
|
height_obs_var(2) = sq(1.5f * math::constrain(_gps_sample_delayed.vacc, lower_limit, upper_limit));
|
|
// innovation gate size
|
|
height_innov_gate(1) = fmaxf(_params.baro_innov_gate, 1.0f);
|
|
|
|
} else if (_control_status.flags.rng_hgt && (_R_rng_to_earth_2_2 > _params.range_cos_max_tilt)) {
|
|
// use range finder with tilt correction
|
|
height_innov(2) = _state.pos(2) - (-math::max(_range_sample_delayed.rng * _R_rng_to_earth_2_2,
|
|
_params.rng_gnd_clearance)) - _hgt_sensor_offset;
|
|
// observation variance - user parameter defined
|
|
height_obs_var(2) = fmaxf((sq(_params.range_noise) + sq(_params.range_noise_scaler * _range_sample_delayed.rng)) * sq(_R_rng_to_earth_2_2), 0.01f);
|
|
// innovation gate size
|
|
height_innov_gate(1) = fmaxf(_params.range_innov_gate, 1.0f);
|
|
|
|
} else if (_control_status.flags.ev_hgt) {
|
|
// calculate the innovation assuming the external vision observation is in local NED frame
|
|
height_innov(2) = _state.pos(2) - _ev_sample_delayed.pos(2);
|
|
// observation variance - defined externally
|
|
height_obs_var(2) = sq(fmaxf(_ev_sample_delayed.hgtErr, 0.01f));
|
|
// innovation gate size
|
|
height_innov_gate(1) = fmaxf(_params.ev_pos_innov_gate, 1.0f);
|
|
}
|
|
// fuse height inforamtion
|
|
fuseVerticalPosition(height_innov,height_innov_gate,
|
|
height_obs_var, height_innov_var,height_test_ratio);
|
|
|
|
// This is a temporary hack until we do proper height sensor fusion
|
|
_gps_pos_innov(2) = height_innov(2);
|
|
_gps_pos_innov_var(2) = height_innov_var(2);
|
|
_gps_pos_test_ratio(1) = height_test_ratio(1);
|
|
}
|
|
|
|
}
|
|
|
|
void Ekf::checkRangeAidSuitability()
|
|
{
|
|
const bool horz_vel_valid = _control_status.flags.gps
|
|
|| _control_status.flags.ev_pos
|
|
|| _control_status.flags.ev_vel
|
|
|| _control_status.flags.opt_flow;
|
|
|
|
if (_control_status.flags.in_air
|
|
&& _rng_hgt_valid
|
|
&& isTerrainEstimateValid()
|
|
&& horz_vel_valid) {
|
|
// check if we can use range finder measurements to estimate height, use hysteresis to avoid rapid switching
|
|
// Note that the 0.7 coefficients and the innovation check are arbitrary values but work well in practice
|
|
const bool is_in_range = _is_range_aid_suitable
|
|
? (_terrain_vpos - _state.pos(2) < _params.max_hagl_for_range_aid)
|
|
: (_terrain_vpos - _state.pos(2) < _params.max_hagl_for_range_aid * 0.7f);
|
|
|
|
const float ground_vel = sqrtf(_state.vel(0) * _state.vel(0) + _state.vel(1) * _state.vel(1));
|
|
const bool is_below_max_speed = _is_range_aid_suitable
|
|
? ground_vel < _params.max_vel_for_range_aid
|
|
: ground_vel < _params.max_vel_for_range_aid * 0.7f;
|
|
|
|
const bool is_hagl_stable = _is_range_aid_suitable
|
|
? ((_hagl_innov * _hagl_innov / (sq(_params.range_aid_innov_gate) * _hagl_innov_var)) < 1.0f)
|
|
: ((_hagl_innov * _hagl_innov / (sq(_params.range_aid_innov_gate) * _hagl_innov_var)) < 0.01f);
|
|
|
|
_is_range_aid_suitable = is_in_range && is_below_max_speed && is_hagl_stable;
|
|
|
|
} else {
|
|
_is_range_aid_suitable = false;
|
|
}
|
|
}
|
|
|
|
void Ekf::controlAirDataFusion()
|
|
{
|
|
// control activation and initialisation/reset of wind states required for airspeed fusion
|
|
|
|
// If both airspeed and sideslip fusion have timed out and we are not using a drag observation model then we no longer have valid wind estimates
|
|
bool airspeed_timed_out = ((_time_last_imu - _time_last_arsp_fuse) > (uint64_t)10e6);
|
|
bool sideslip_timed_out = ((_time_last_imu - _time_last_beta_fuse) > (uint64_t)10e6);
|
|
|
|
if (_control_status.flags.wind && airspeed_timed_out && sideslip_timed_out && !(_params.fusion_mode & MASK_USE_DRAG)) {
|
|
_control_status.flags.wind = false;
|
|
|
|
}
|
|
|
|
if (_control_status.flags.fuse_aspd && airspeed_timed_out) {
|
|
_control_status.flags.fuse_aspd = false;
|
|
|
|
}
|
|
|
|
// Always try to fuse airspeed data if available and we are in flight
|
|
if (_tas_data_ready && _control_status.flags.in_air) {
|
|
// always fuse airsped data if we are flying and data is present
|
|
if (!_control_status.flags.fuse_aspd) {
|
|
_control_status.flags.fuse_aspd = true;
|
|
}
|
|
|
|
// If starting wind state estimation, reset the wind states and covariances before fusing any data
|
|
if (!_control_status.flags.wind) {
|
|
// activate the wind states
|
|
_control_status.flags.wind = true;
|
|
// reset the timout timer to prevent repeated resets
|
|
_time_last_arsp_fuse = _time_last_imu;
|
|
_time_last_beta_fuse = _time_last_imu;
|
|
// reset the wind speed states and corresponding covariances
|
|
resetWindStates();
|
|
resetWindCovariance();
|
|
|
|
}
|
|
|
|
fuseAirspeed();
|
|
|
|
}
|
|
}
|
|
|
|
void Ekf::controlBetaFusion()
|
|
{
|
|
// control activation and initialisation/reset of wind states required for synthetic sideslip fusion fusion
|
|
|
|
// If both airspeed and sideslip fusion have timed out and we are not using a drag observation model then we no longer have valid wind estimates
|
|
bool sideslip_timed_out = ((_time_last_imu - _time_last_beta_fuse) > (uint64_t)10e6);
|
|
bool airspeed_timed_out = ((_time_last_imu - _time_last_arsp_fuse) > (uint64_t)10e6);
|
|
|
|
if (_control_status.flags.wind && airspeed_timed_out && sideslip_timed_out && !(_params.fusion_mode & MASK_USE_DRAG)) {
|
|
_control_status.flags.wind = false;
|
|
}
|
|
|
|
// Perform synthetic sideslip fusion when in-air and sideslip fuson had been enabled externally in addition to the following criteria:
|
|
|
|
// Sufficient time has lapsed sice the last fusion
|
|
bool beta_fusion_time_triggered = ((_time_last_imu - _time_last_beta_fuse) > _params.beta_avg_ft_us);
|
|
|
|
if (beta_fusion_time_triggered && _control_status.flags.fuse_beta && _control_status.flags.in_air) {
|
|
// If starting wind state estimation, reset the wind states and covariances before fusing any data
|
|
if (!_control_status.flags.wind) {
|
|
// activate the wind states
|
|
_control_status.flags.wind = true;
|
|
// reset the timeout timers to prevent repeated resets
|
|
_time_last_beta_fuse = _time_last_imu;
|
|
_time_last_arsp_fuse = _time_last_imu;
|
|
// reset the wind speed states and corresponding covariances
|
|
resetWindStates();
|
|
resetWindCovariance();
|
|
}
|
|
|
|
fuseSideslip();
|
|
}
|
|
}
|
|
|
|
void Ekf::controlDragFusion()
|
|
{
|
|
if (_params.fusion_mode & MASK_USE_DRAG) {
|
|
if (_control_status.flags.in_air
|
|
&& !_mag_inhibit_yaw_reset_req) {
|
|
if (!_control_status.flags.wind) {
|
|
// reset the wind states and covariances when starting drag accel fusion
|
|
_control_status.flags.wind = true;
|
|
resetWindStates();
|
|
resetWindCovariance();
|
|
|
|
} else if (_drag_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_drag_sample_delayed)) {
|
|
fuseDrag();
|
|
|
|
}
|
|
|
|
} else {
|
|
_control_status.flags.wind = false;
|
|
|
|
}
|
|
}
|
|
}
|
|
|
|
void Ekf::controlFakePosFusion()
|
|
{
|
|
// if we aren't doing any aiding, fake position measurements at the last known position to constrain drift
|
|
// Coincide fake measurements with baro data for efficiency with a minimum fusion rate of 5Hz
|
|
|
|
if (!_control_status.flags.gps &&
|
|
!_control_status.flags.opt_flow &&
|
|
!_control_status.flags.ev_pos &&
|
|
!_control_status.flags.ev_vel &&
|
|
!(_control_status.flags.fuse_aspd && _control_status.flags.fuse_beta)) {
|
|
|
|
// We now need to use a synthetic position observation to prevent unconstrained drift of the INS states.
|
|
_using_synthetic_position = true;
|
|
|
|
// Fuse synthetic position observations every 200msec
|
|
if (((_time_last_imu - _time_last_fake_pos) > (uint64_t)2e5) || _fuse_height) {
|
|
|
|
Vector3f fake_gps_pos_obs_var{};
|
|
Vector2f fake_gps_pos_innov_gate{};
|
|
|
|
|
|
// Reset position and velocity states if we re-commence this aiding method
|
|
if ((_time_last_imu - _time_last_fake_pos) > (uint64_t)4e5) {
|
|
resetPosition();
|
|
resetVelocity();
|
|
_fuse_hpos_as_odom = false;
|
|
|
|
if (_time_last_fake_pos != 0) {
|
|
ECL_WARN_TIMESTAMPED("EKF stopping navigation");
|
|
}
|
|
|
|
}
|
|
_time_last_fake_pos = _time_last_imu;
|
|
|
|
if (_control_status.flags.in_air && _control_status.flags.tilt_align) {
|
|
fake_gps_pos_obs_var(0) = fake_gps_pos_obs_var(1) = fmaxf(_params.pos_noaid_noise, _params.gps_pos_noise);
|
|
|
|
} else {
|
|
fake_gps_pos_obs_var(0) = fake_gps_pos_obs_var(1) = 0.5f;
|
|
}
|
|
|
|
_gps_pos_innov(0) = _state.pos(0) - _last_known_posNE(0);
|
|
_gps_pos_innov(1) = _state.pos(1) - _last_known_posNE(1);
|
|
|
|
// glitch protection is not required so set gate to a large value
|
|
fake_gps_pos_innov_gate(0) = 100.0f;
|
|
|
|
fuseHorizontalPosition(_gps_pos_innov, fake_gps_pos_innov_gate, fake_gps_pos_obs_var,
|
|
_gps_pos_innov_var, _gps_pos_test_ratio);
|
|
}
|
|
|
|
} else {
|
|
_using_synthetic_position = false;
|
|
}
|
|
|
|
}
|
|
|
|
void Ekf::controlAuxVelFusion()
|
|
{
|
|
bool data_ready = _auxvel_buffer.pop_first_older_than(_imu_sample_delayed.time_us, &_auxvel_sample_delayed);
|
|
bool primary_aiding = _control_status.flags.gps || _control_status.flags.ev_pos || _control_status.flags.ev_vel || _control_status.flags.opt_flow;
|
|
|
|
if (data_ready && primary_aiding) {
|
|
|
|
Vector2f aux_vel_innov_gate{};
|
|
Vector3f aux_vel_obs_var{};
|
|
|
|
_aux_vel_innov(0) = _state.vel(0) - _auxvel_sample_delayed.velNE(0);
|
|
_aux_vel_innov(1) = _state.vel(1) - _auxvel_sample_delayed.velNE(1);
|
|
aux_vel_innov_gate(0) = _params.auxvel_gate;
|
|
aux_vel_obs_var(0) = _auxvel_sample_delayed.velVarNE(0);
|
|
aux_vel_obs_var(1) = _auxvel_sample_delayed.velVarNE(1);
|
|
|
|
fuseHorizontalVelocity(_aux_vel_innov, aux_vel_innov_gate, aux_vel_obs_var,
|
|
_aux_vel_innov_var, _aux_vel_test_ratio);
|
|
|
|
}
|
|
}
|