forked from Archive/PX4-Autopilot
673 lines
34 KiB
C++
673 lines
34 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 ekf.h
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* Class for core functions for ekf attitude and position estimator.
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*
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* @author Roman Bast <bapstroman@gmail.com>
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* @author Paul Riseborough <p_riseborough@live.com.au>
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*
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*/
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#pragma once
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#include "estimator_interface.h"
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class Ekf : public EstimatorInterface
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{
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public:
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Ekf() = default;
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~Ekf() = default;
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// initialise variables to sane values (also interface class)
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bool init(uint64_t timestamp);
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// should be called every time new data is pushed into the filter
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bool update();
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// gets the innovations of velocity and position measurements
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// 0-2 vel, 3-5 pos
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void get_vel_pos_innov(float vel_pos_innov[6]);
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// gets the innovations for of the NE auxiliary velocity measurement
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void get_aux_vel_innov(float aux_vel_innov[2]);
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// gets the innovations of the earth magnetic field measurements
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void get_mag_innov(float mag_innov[3]);
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// gets the innovations of the heading measurement
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void get_heading_innov(float *heading_innov);
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// gets the innovation variances of velocity and position measurements
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// 0-2 vel, 3-5 pos
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void get_vel_pos_innov_var(float vel_pos_innov_var[6]);
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// gets the innovation variances of the earth magnetic field measurements
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void get_mag_innov_var(float mag_innov_var[3]);
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// gets the innovations of airspeed measurement
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void get_airspeed_innov(float *airspeed_innov);
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// gets the innovation variance of the airspeed measurement
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void get_airspeed_innov_var(float *airspeed_innov_var);
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// gets the innovations of synthetic sideslip measurement
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void get_beta_innov(float *beta_innov);
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// gets the innovation variance of the synthetic sideslip measurement
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void get_beta_innov_var(float *beta_innov_var);
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// gets the innovation variance of the heading measurement
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void get_heading_innov_var(float *heading_innov_var);
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// gets the innovation variance of the flow measurement
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void get_flow_innov_var(float flow_innov_var[2]);
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// gets the innovation of the flow measurement
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void get_flow_innov(float flow_innov[2]);
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// gets the innovation variance of the drag specific force measurement
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void get_drag_innov_var(float drag_innov_var[2]);
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// gets the innovation of the drag specific force measurement
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void get_drag_innov(float drag_innov[2]);
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// gets the innovation variance of the HAGL measurement
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void get_hagl_innov_var(float *hagl_innov_var);
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// gets the innovation of the HAGL measurement
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void get_hagl_innov(float *hagl_innov);
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// get the state vector at the delayed time horizon
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void get_state_delayed(float *state);
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// get the wind velocity in m/s
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void get_wind_velocity(float *wind);
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// get the wind velocity var
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void get_wind_velocity_var(float *wind_var);
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// get the true airspeed in m/s
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void get_true_airspeed(float *tas);
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// get the diagonal elements of the covariance matrix
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void get_covariances(float *covariances);
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// ask estimator for sensor data collection decision and do any preprocessing if required, returns true if not defined
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bool collect_gps(uint64_t time_usec, struct gps_message *gps);
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bool collect_imu(const imuSample &imu);
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// get the ekf WGS-84 origin position and height and the system time it was last set
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// return true if the origin is valid
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bool get_ekf_origin(uint64_t *origin_time, map_projection_reference_s *origin_pos, float *origin_alt);
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// get the 1-sigma horizontal and vertical position uncertainty of the ekf WGS-84 position
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void get_ekf_gpos_accuracy(float *ekf_eph, float *ekf_epv);
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// get the 1-sigma horizontal and vertical position uncertainty of the ekf local position
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void get_ekf_lpos_accuracy(float *ekf_eph, float *ekf_epv);
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// get the 1-sigma horizontal and vertical velocity uncertainty
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void get_ekf_vel_accuracy(float *ekf_evh, float *ekf_evv);
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// get the vehicle control limits required by the estimator to keep within sensor limitations
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void get_ekf_ctrl_limits(float *vxy_max, float *vz_max, float *hagl_min, float *hagl_max);
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/*
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Reset all IMU bias states and covariances to initial alignment values.
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Use when the IMU sensor has changed.
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Returns true if reset performed, false if rejected due to less than 10 seconds lapsed since last reset.
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*/
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bool reset_imu_bias();
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void get_vel_var(Vector3f &vel_var);
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void get_pos_var(Vector3f &pos_var);
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// return an array containing the output predictor angular, velocity and position tracking
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// error magnitudes (rad), (m/sec), (m)
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void get_output_tracking_error(float error[3]);
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/*
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Returns following IMU vibration metrics in the following array locations
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0 : Gyro delta angle coning metric = filtered length of (delta_angle x prev_delta_angle)
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1 : Gyro high frequency vibe = filtered length of (delta_angle - prev_delta_angle)
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2 : Accel high frequency vibe = filtered length of (delta_velocity - prev_delta_velocity)
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*/
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void get_imu_vibe_metrics(float vibe[3]);
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/*
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First argument returns GPS drift metrics in the following array locations
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0 : Horizontal position drift rate (m/s)
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1 : Vertical position drift rate (m/s)
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2 : Filtered horizontal velocity (m/s)
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Second argument returns true when IMU movement is blocking the drift calculation
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Function returns true if the metrics have been updated and not returned previously by this function
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*/
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bool get_gps_drift_metrics(float drift[3], bool *blocked);
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// return true if the global position estimate is valid
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bool global_position_is_valid();
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// check if the EKF is dead reckoning horizontal velocity using inertial data only
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void update_deadreckoning_status();
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// return true if the terrain estimate is valid
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bool get_terrain_valid();
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// update terrain validity status
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void update_terrain_valid();
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// get the estimated terrain vertical position relative to the NED origin
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void get_terrain_vert_pos(float *ret);
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// get the accerometer bias in m/s/s
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void get_accel_bias(float bias[3]);
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// get the gyroscope bias in rad/s
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void get_gyro_bias(float bias[3]);
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// get GPS check status
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void get_gps_check_status(uint16_t *val);
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// return the amount the local vertical position changed in the last reset and the number of reset events
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void get_posD_reset(float *delta, uint8_t *counter) {*delta = _state_reset_status.posD_change; *counter = _state_reset_status.posD_counter;}
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// return the amount the local vertical velocity changed in the last reset and the number of reset events
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void get_velD_reset(float *delta, uint8_t *counter) {*delta = _state_reset_status.velD_change; *counter = _state_reset_status.velD_counter;}
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// return the amount the local horizontal position changed in the last reset and the number of reset events
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void get_posNE_reset(float delta[2], uint8_t *counter)
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{
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memcpy(delta, &_state_reset_status.posNE_change._data[0], sizeof(_state_reset_status.posNE_change._data));
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*counter = _state_reset_status.posNE_counter;
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}
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// return the amount the local horizontal velocity changed in the last reset and the number of reset events
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void get_velNE_reset(float delta[2], uint8_t *counter)
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{
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memcpy(delta, &_state_reset_status.velNE_change._data[0], sizeof(_state_reset_status.velNE_change._data));
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*counter = _state_reset_status.velNE_counter;
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}
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// return the amount the quaternion has changed in the last reset and the number of reset events
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void get_quat_reset(float delta_quat[4], uint8_t *counter)
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{
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memcpy(delta_quat, &_state_reset_status.quat_change._data[0], sizeof(_state_reset_status.quat_change._data));
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*counter = _state_reset_status.quat_counter;
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}
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// get EKF innovation consistency check status information comprising of:
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// status - a bitmask integer containing the pass/fail status for each EKF measurement innovation consistency check
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// Innovation Test Ratios - these are the ratio of the innovation to the acceptance threshold.
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// A value > 1 indicates that the sensor measurement has exceeded the maximum acceptable level and has been rejected by the EKF
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// Where a measurement type is a vector quantity, eg magnetoemter, GPS position, etc, the maximum value is returned.
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void get_innovation_test_status(uint16_t *status, float *mag, float *vel, float *pos, float *hgt, float *tas, float *hagl, float *beta);
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// return a bitmask integer that describes which state estimates can be used for flight control
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void get_ekf_soln_status(uint16_t *status);
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// return the quaternion defining the rotation from the EKF to the External Vision reference frame
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void get_ekf2ev_quaternion(float *quat);
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// use the latest IMU data at the current time horizon.
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Quatf calculate_quaternion() const;
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private:
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static constexpr uint8_t _k_num_states{24}; ///< number of EKF states
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struct {
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uint8_t velNE_counter; ///< number of horizontal position reset events (allow to wrap if count exceeds 255)
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uint8_t velD_counter; ///< number of vertical velocity reset events (allow to wrap if count exceeds 255)
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uint8_t posNE_counter; ///< number of horizontal position reset events (allow to wrap if count exceeds 255)
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uint8_t posD_counter; ///< number of vertical position reset events (allow to wrap if count exceeds 255)
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uint8_t quat_counter; ///< number of quaternion reset events (allow to wrap if count exceeds 255)
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Vector2f velNE_change; ///< North East velocity change due to last reset (m)
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float velD_change; ///< Down velocity change due to last reset (m/sec)
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Vector2f posNE_change; ///< North, East position change due to last reset (m)
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float posD_change; ///< Down position change due to last reset (m)
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Quatf quat_change; ///< quaternion delta due to last reset - multiply pre-reset quaternion by this to get post-reset quaternion
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} _state_reset_status{}; ///< reset event monitoring structure containing velocity, position, height and yaw reset information
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float _dt_ekf_avg{FILTER_UPDATE_PERIOD_S}; ///< average update rate of the ekf
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float _dt_update{0.01f}; ///< delta time since last ekf update. This time can be used for filters which run at the same rate as the Ekf::update() function. (sec)
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stateSample _state{}; ///< state struct of the ekf running at the delayed time horizon
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bool _filter_initialised{false}; ///< true when the EKF sttes and covariances been initialised
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bool _earth_rate_initialised{false}; ///< true when we know the earth rotatin rate (requires GPS)
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bool _fuse_height{false}; ///< true when baro height data should be fused
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bool _fuse_pos{false}; ///< true when gps position data should be fused
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bool _fuse_hor_vel{false}; ///< true when gps horizontal velocity measurement should be fused
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bool _fuse_vert_vel{false}; ///< true when gps vertical velocity measurement should be fused
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bool _fuse_hor_vel_aux{false}; ///< true when auxiliary horizontal velocity measurement should be fused
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float _posObsNoiseNE{0.0f}; ///< 1-STD observtion noise used for the fusion of NE position data (m)
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float _posInnovGateNE{1.0f}; ///< Number of standard deviations used for the NE position fusion innovation consistency check
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Vector2f _velObsVarNE; ///< 1-STD observation noise variance used for the fusion of NE velocity data (m/sec)**2
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float _hvelInnovGate{1.0f}; ///< Number of standard deviations used for the horizontal velocity fusion innovation consistency check
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// variables used when position data is being fused using a relative position odometry model
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bool _fuse_hpos_as_odom{false}; ///< true when the NE position data is being fused using an odometry assumption
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Vector3f _pos_meas_prev; ///< previous value of NED position measurement fused using odometry assumption (m)
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Vector2f _hpos_pred_prev; ///< previous value of NE position state used by odometry fusion (m)
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bool _hpos_prev_available{false}; ///< true when previous values of the estimate and measurement are available for use
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Vector3f _ev_rot_vec_filt; ///< filtered rotation vector defining the rotation from EKF to EV reference (rad)
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Dcmf _ev_rot_mat; ///< transformation matrix that rotates observations from the EV to the EKF navigation frame
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uint64_t _ev_rot_last_time_us{0}; ///< previous time that the calculation of the ekf to ev rotation matrix was updated (uSec)
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// booleans true when fresh sensor data is available at the fusion time horizon
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bool _gps_data_ready{false}; ///< true when new GPS data has fallen behind the fusion time horizon and is available to be fused
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bool _mag_data_ready{false}; ///< true when new magnetometer data has fallen behind the fusion time horizon and is available to be fused
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bool _baro_data_ready{false}; ///< true when new baro height data has fallen behind the fusion time horizon and is available to be fused
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bool _range_data_ready{false}; ///< true when new range finder data has fallen behind the fusion time horizon and is available to be fused
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bool _flow_data_ready{false}; ///< true when the leading edge of the optical flow integration period has fallen behind the fusion time horizon
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bool _ev_data_ready{false}; ///< true when new external vision system data has fallen behind the fusion time horizon and is available to be fused
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bool _tas_data_ready{false}; ///< true when new true airspeed data has fallen behind the fusion time horizon and is available to be fused
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uint64_t _time_last_fake_gps{0}; ///< last time we faked GPS position measurements to constrain tilt errors during operation without external aiding (uSec)
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uint64_t _time_ins_deadreckon_start{0}; ///< amount of time we have been doing inertial only deadreckoning (uSec)
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bool _using_synthetic_position{false}; ///< true if we are using a synthetic position to constrain drift
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uint64_t _time_last_pos_fuse{0}; ///< time the last fusion of horizontal position measurements was performed (uSec)
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uint64_t _time_last_delpos_fuse{0}; ///< time the last fusion of incremental horizontal position measurements was performed (uSec)
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uint64_t _time_last_vel_fuse{0}; ///< time the last fusion of velocity measurements was performed (uSec)
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uint64_t _time_last_hgt_fuse{0}; ///< time the last fusion of height measurements was performed (uSec)
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uint64_t _time_last_of_fuse{0}; ///< time the last fusion of optical flow measurements were performed (uSec)
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uint64_t _time_last_arsp_fuse{0}; ///< time the last fusion of airspeed measurements were performed (uSec)
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uint64_t _time_last_beta_fuse{0}; ///< time the last fusion of synthetic sideslip measurements were performed (uSec)
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uint64_t _time_last_rng_ready{0}; ///< time the last range finder measurement was ready (uSec)
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Vector2f _last_known_posNE; ///< last known local NE position vector (m)
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float _imu_collection_time_adj{0.0f}; ///< the amount of time the IMU collection needs to be advanced to meet the target set by FILTER_UPDATE_PERIOD_MS (sec)
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uint64_t _time_acc_bias_check{0}; ///< last time the accel bias check passed (uSec)
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uint64_t _delta_time_baro_us{0}; ///< delta time between two consecutive delayed baro samples from the buffer (uSec)
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uint64_t _last_imu_bias_cov_reset_us{0}; ///< time the last reset of IMU delta angle and velocity state covariances was performed (uSec)
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Vector3f _earth_rate_NED; ///< earth rotation vector (NED) in rad/s
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Dcmf _R_to_earth; ///< transformation matrix from body frame to earth frame from last EKF predition
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// used by magnetometer fusion mode selection
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Vector2f _accel_lpf_NE; ///< Low pass filtered horizontal earth frame acceleration (m/sec**2)
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float _yaw_delta_ef{0.0f}; ///< Recent change in yaw angle measured about the earth frame D axis (rad)
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float _yaw_rate_lpf_ef{0.0f}; ///< Filtered angular rate about earth frame D axis (rad/sec)
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bool _mag_bias_observable{false}; ///< true when there is enough rotation to make magnetometer bias errors observable
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bool _yaw_angle_observable{false}; ///< true when there is enough horizontal acceleration to make yaw observable
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uint64_t _time_yaw_started{0}; ///< last system time in usec that a yaw rotation moaneouvre was detected
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uint8_t _num_bad_flight_yaw_events{0}; ///< number of times a bad heading has been detected in flight and required a yaw reset
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uint64_t _mag_use_not_inhibit_us{0}; ///< last system time in usec before magnetomer use was inhibited
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bool _mag_use_inhibit{false}; ///< true when magnetomer use is being inhibited
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bool _mag_use_inhibit_prev{false}; ///< true when magnetomer use was being inhibited the previous frame
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bool _mag_inhibit_yaw_reset_req{false}; ///< true when magnetomer inhibit has been active for long enough to require a yaw reset when conditons improve.
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float _last_static_yaw{0.0f}; ///< last yaw angle recorded when on ground motion checks were passing (rad)
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bool _vehicle_at_rest_prev{false}; ///< true when the vehicle was at rest the previous time the status was checked
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bool _mag_yaw_reset_req{false}; ///< true when a reset of the yaw using the magnetomer data has been requested
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float P[_k_num_states][_k_num_states] {}; ///< state covariance matrix
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float _vel_pos_innov[6] {}; ///< NED velocity and position innovations: 0-2 vel (m/sec), 3-5 pos (m)
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float _vel_pos_innov_var[6] {}; ///< NED velocity and position innovation variances: 0-2 vel ((m/sec)**2), 3-5 pos (m**2)
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float _aux_vel_innov[2] {}; ///< NE auxiliary velocity innovations: (m/sec)
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float _mag_innov[3] {}; ///< earth magnetic field innovations (Gauss)
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float _mag_innov_var[3] {}; ///< earth magnetic field innovation variance (Gauss**2)
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float _airspeed_innov{0.0f}; ///< airspeed measurement innovation (m/sec)
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float _airspeed_innov_var{0.0f}; ///< airspeed measurement innovation variance ((m/sec)**2)
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float _beta_innov{0.0f}; ///< synthetic sideslip measurement innovation (rad)
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float _beta_innov_var{0.0f}; ///< synthetic sideslip measurement innovation variance (rad**2)
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float _drag_innov[2] {}; ///< multirotor drag measurement innovation (m/sec**2)
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float _drag_innov_var[2] {}; ///< multirotor drag measurement innovation variance ((m/sec**2)**2)
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float _heading_innov{0.0f}; ///< heading measurement innovation (rad)
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float _heading_innov_var{0.0f}; ///< heading measurement innovation variance (rad**2)
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// optical flow processing
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float _flow_innov[2] {}; ///< flow measurement innovation (rad/sec)
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float _flow_innov_var[2] {}; ///< flow innovation variance ((rad/sec)**2)
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Vector3f _flow_gyro_bias; ///< bias errors in optical flow sensor rate gyro outputs (rad/sec)
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Vector3f _imu_del_ang_of; ///< bias corrected delta angle measurements accumulated across the same time frame as the optical flow rates (rad)
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float _delta_time_of{0.0f}; ///< time in sec that _imu_del_ang_of was accumulated over (sec)
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uint64_t _time_bad_motion_us{0}; ///< last system time that on-ground motion exceeded limits (uSec)
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uint64_t _time_good_motion_us{0}; ///< last system time that on-ground motion was within limits (uSec)
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bool _inhibit_flow_use{false}; ///< true when use of optical flow and range finder is being inhibited
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Vector2f _flowRadXYcomp; ///< measured delta angle of the image about the X and Y body axes after removal of body rotation (rad), RH rotation is positive
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float _mag_declination{0.0f}; ///< magnetic declination used by reset and fusion functions (rad)
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// output predictor states
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Vector3f _delta_angle_corr; ///< delta angle correction vector (rad)
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imuSample _imu_down_sampled{}; ///< down sampled imu data (sensor rate -> filter update rate)
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Quatf _q_down_sampled; ///< down sampled quaternion (tracking delta angles between ekf update steps)
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Vector3f _vel_err_integ; ///< integral of velocity tracking error (m)
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Vector3f _pos_err_integ; ///< integral of position tracking error (m.s)
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float _output_tracking_error[3] {}; ///< contains the magnitude of the angle, velocity and position track errors (rad, m/s, m)
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// variables used for the GPS quality checks
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float _gpsDriftVelN{0.0f}; ///< GPS north position derivative (m/sec)
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float _gpsDriftVelE{0.0f}; ///< GPS east position derivative (m/sec)
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float _gps_drift_velD{0.0f}; ///< GPS down position derivative (m/sec)
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float _gps_velD_diff_filt{0.0f}; ///< GPS filtered Down velocity (m/sec)
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float _gps_velN_filt{0.0f}; ///< GPS filtered North velocity (m/sec)
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float _gps_velE_filt{0.0f}; ///< GPS filtered East velocity (m/sec)
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uint64_t _last_gps_fail_us{0}; ///< last system time in usec that the GPS failed it's checks
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uint64_t _last_gps_pass_us{0}; ///< last system time in usec that the GPS passed it's checks
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float _gps_error_norm{1.0f}; ///< normalised gps error
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// Variables used to publish the WGS-84 location of the EKF local NED origin
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uint64_t _last_gps_origin_time_us{0}; ///< time the origin was last set (uSec)
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float _gps_alt_ref{0.0f}; ///< WGS-84 height (m)
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// Variables used to initialise the filter states
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uint32_t _hgt_counter{0}; ///< number of height samples read during initialisation
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float _rng_filt_state{0.0f}; ///< filtered height measurement (m)
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uint32_t _mag_counter{0}; ///< number of magnetometer samples read during initialisation
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uint32_t _ev_counter{0}; ///< number of external vision samples read during initialisation
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uint64_t _time_last_mag{0}; ///< measurement time of last magnetomter sample (uSec)
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Vector3f _mag_filt_state; ///< filtered magnetometer measurement (Gauss)
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Vector3f _delVel_sum; ///< summed delta velocity (m/sec)
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float _hgt_sensor_offset{0.0f}; ///< set as necessary if desired to maintain the same height after a height reset (m)
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float _baro_hgt_offset{0.0f}; ///< baro height reading at the local NED origin (m)
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// Variables used to control activation of post takeoff functionality
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float _last_on_ground_posD{0.0f}; ///< last vertical position when the in_air status was false (m)
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bool _flt_mag_align_complete{false}; ///< true when the in-flight mag field alignment has been completed
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bool _flt_mag_align_converging{false}; ///< true when the in-flight mag field post alignment convergence is being performd
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uint64_t _flt_mag_align_start_time{0}; ///< time that inflight magnetic field alignment started (uSec)
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uint64_t _time_last_movement{0}; ///< last system time that sufficient movement to use 3-axis magnetometer fusion was detected (uSec)
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float _saved_mag_variance[6] {}; ///< magnetic field state variances that have been saved for use at the next initialisation (Gauss**2)
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bool _velpos_reset_request{false}; ///< true when a large yaw error has been fixed and a velocity and position state reset is required
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gps_check_fail_status_u _gps_check_fail_status{};
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// variables used to inhibit accel bias learning
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bool _accel_bias_inhibit{false}; ///< true when the accel bias learning is being inhibited
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Vector3f _accel_vec_filt{}; ///< acceleration vector after application of a low pass filter (m/sec**2)
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float _accel_mag_filt{0.0f}; ///< acceleration magnitude after application of a decaying envelope filter (rad/sec)
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float _ang_rate_mag_filt{0.0f}; ///< angular rate magnitude after application of a decaying envelope filter (rad/sec)
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Vector3f _prev_dvel_bias_var; ///< saved delta velocity XYZ bias variances (m/sec)**2
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// Terrain height state estimation
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float _terrain_vpos{0.0f}; ///< estimated vertical position of the terrain underneath the vehicle in local NED frame (m)
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float _terrain_var{1e4f}; ///< variance of terrain position estimate (m**2)
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float _hagl_innov{0.0f}; ///< innovation of the last height above terrain measurement (m)
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float _hagl_innov_var{0.0f}; ///< innovation variance for the last height above terrain measurement (m**2)
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uint64_t _time_last_hagl_fuse{0}; ///< last system time that the hagl measurement failed it's checks (uSec)
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bool _terrain_initialised{false}; ///< true when the terrain estimator has been intialised
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float _sin_tilt_rng{0.0f}; ///< sine of the range finder tilt rotation about the Y body axis
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float _cos_tilt_rng{0.0f}; ///< cosine of the range finder tilt rotation about the Y body axis
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float _R_rng_to_earth_2_2{0.0f}; ///< 2,2 element of the rotation matrix from sensor frame to earth frame
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bool _range_data_continuous{false}; ///< true when we are receiving range finder data faster than a 2Hz average
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float _dt_last_range_update_filt_us{0.0f}; ///< filtered value of the delta time elapsed since the last range measurement came into the filter (uSec)
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bool _hagl_valid{false}; ///< true when the height above ground estimate is valid
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// height sensor fault status
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bool _baro_hgt_faulty{false}; ///< true if valid baro data is unavailable for use
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bool _gps_hgt_faulty{false}; ///< true if valid gps height data is unavailable for use
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bool _rng_hgt_faulty{false}; ///< true if valid range finder height data is unavailable for use
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int _primary_hgt_source{VDIST_SENSOR_BARO}; ///< specifies primary source of height data
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// imu fault status
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uint64_t _time_bad_vert_accel{0}; ///< last time a bad vertical accel was detected (uSec)
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uint64_t _time_good_vert_accel{0}; ///< last time a good vertical accel was detected (uSec)
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bool _bad_vert_accel_detected{false}; ///< true when bad vertical accelerometer data has been detected
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// variables used to control range aid functionality
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bool _range_aid_mode_enabled{false}; ///< true when range finder can be used in flight as the height reference instead of the primary height sensor
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bool _range_aid_mode_selected{false}; ///< true when range finder is being used as the height reference instead of the primary height sensor
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// variables used to check range finder validity data
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float _rng_stuck_min_val{0.0f}; ///< minimum value for new rng measurement when being stuck
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float _rng_stuck_max_val{0.0f}; ///< maximum value for new rng measurement when being stuck
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// update the real time complementary filter states. This includes the prediction
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// and the correction step
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void calculateOutputStates();
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// initialise filter states of both the delayed ekf and the real time complementary filter
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bool initialiseFilter(void);
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// initialise ekf covariance matrix
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void initialiseCovariance();
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// predict ekf state
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void predictState();
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// predict ekf covariance
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void predictCovariance();
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// ekf sequential fusion of magnetometer measurements
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void fuseMag();
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// fuse the first euler angle from either a 321 or 312 rotation sequence as the observation (currently measures yaw using the magnetometer)
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void fuseHeading();
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// fuse the yaw angle obtained from a dual antenna GPS unit
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void fuseGpsAntYaw();
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// reset the quaternions states using the yaw angle obtained from a dual antenna GPS unit
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// return true if the reset was successful
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bool resetGpsAntYaw();
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// fuse magnetometer declination measurement
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void fuseDeclination();
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// fuse airspeed measurement
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void fuseAirspeed();
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// fuse synthetic zero sideslip measurement
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void fuseSideslip();
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// fuse body frame drag specific forces for multi-rotor wind estimation
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void fuseDrag();
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// fuse velocity and position measurements (also barometer height)
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void fuseVelPosHeight();
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// reset velocity states of the ekf
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bool resetVelocity();
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// fuse optical flow line of sight rate measurements
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void fuseOptFlow();
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// calculate optical flow body angular rate compensation
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// returns false if bias corrected body rate data is unavailable
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bool calcOptFlowBodyRateComp();
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// initialise the terrain vertical position estimator
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// return true if the initialisation is successful
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bool initHagl();
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// run the terrain estimator
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void runTerrainEstimator();
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// update the terrain vertical position estimate using a height above ground measurement from the range finder
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void fuseHagl();
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// reset the heading and magnetic field states using the declination and magnetometer measurements
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// return true if successful
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bool resetMagHeading(Vector3f &mag_init);
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// Do a forced re-alignment of the yaw angle to align with the horizontal velocity vector from the GPS.
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|
// It is used to align the yaw angle after launch or takeoff for fixed wing vehicle.
|
|
bool realignYawGPS();
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// calculate the magnetic declination to be used by the alignment and fusion processing
|
|
void calcMagDeclination();
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// reset position states of the ekf (only horizontal position)
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|
bool resetPosition();
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// reset height state of the ekf
|
|
void resetHeight();
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// modify output filter to match the the EKF state at the fusion time horizon
|
|
void alignOutputFilter();
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// update the estimated angular misalignment vector between the EV naigration frame and the EKF navigation frame
|
|
// and update the rotation matrix which transforms EV navigation frame measurements into NED
|
|
void calcExtVisRotMat();
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// reset the estimated angular misalignment vector between the EV naigration frame and the EKF navigation frame
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|
// and reset the rotation matrix which transforms EV navigation frame measurements into NED
|
|
void resetExtVisRotMat();
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|
|
// limit the diagonal of the covariance matrix
|
|
void fixCovarianceErrors();
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|
|
// make ekf covariance matrix symmetric between a nominated state indexe range
|
|
void makeSymmetrical(float (&cov_mat)[_k_num_states][_k_num_states], uint8_t first, uint8_t last);
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// constrain the ekf states
|
|
void constrainStates();
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|
|
// generic function which will perform a fusion step given a kalman gain K
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|
// and a scalar innovation value
|
|
void fuse(float *K, float innovation);
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|
|
// calculate the earth rotation vector from a given latitude
|
|
void calcEarthRateNED(Vector3f &omega, float lat_rad) const;
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|
|
|
// return true id the GPS quality is good enough to set an origin and start aiding
|
|
bool gps_is_good(struct gps_message *gps);
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|
|
// Control the filter fusion modes
|
|
void controlFusionModes();
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|
|
// control fusion of external vision observations
|
|
void controlExternalVisionFusion();
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|
|
// control fusion of optical flow observtions
|
|
void controlOpticalFlowFusion();
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|
|
// control fusion of GPS observations
|
|
void controlGpsFusion();
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|
|
// control fusion of magnetometer observations
|
|
void controlMagFusion();
|
|
|
|
// control fusion of range finder observations
|
|
void controlRangeFinderFusion();
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|
|
// control fusion of air data observations
|
|
void controlAirDataFusion();
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|
|
|
// control fusion of synthetic sideslip observations
|
|
void controlBetaFusion();
|
|
|
|
// control fusion of multi-rotor drag specific force observations
|
|
void controlDragFusion();
|
|
|
|
// control fusion of pressure altitude observations
|
|
void controlBaroFusion();
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|
|
|
// control fusion of velocity and position observations
|
|
void controlVelPosFusion();
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|
|
|
// control fusion of auxiliary velocity observations
|
|
void controlAuxVelFusion();
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|
|
|
// control for height sensor timeouts, sensor changes and state resets
|
|
void controlHeightSensorTimeouts();
|
|
|
|
// control for combined height fusion mode (implemented for switching between baro and range height)
|
|
void controlHeightFusion();
|
|
|
|
// determine if flight condition is suitable so use range finder instead of the primary height senor
|
|
void rangeAidConditionsMet();
|
|
|
|
// check for "stuck" range finder measurements when rng was not valid for certain period
|
|
void checkRangeDataValidity();
|
|
|
|
// return the square of two floating point numbers - used in auto coded sections
|
|
static constexpr float sq(float var) { return var * var; }
|
|
|
|
// set control flags to use baro height
|
|
void setControlBaroHeight();
|
|
|
|
// set control flags to use range height
|
|
void setControlRangeHeight();
|
|
|
|
// set control flags to use GPS height
|
|
void setControlGPSHeight();
|
|
|
|
// set control flags to use external vision height
|
|
void setControlEVHeight();
|
|
|
|
// zero the specified range of rows in the state covariance matrix
|
|
void zeroRows(float (&cov_mat)[_k_num_states][_k_num_states], uint8_t first, uint8_t last);
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|
|
|
// zero the specified range of columns in the state covariance matrix
|
|
void zeroCols(float (&cov_mat)[_k_num_states][_k_num_states], uint8_t first, uint8_t last);
|
|
|
|
// zero the specified range of off diagonals in the state covariance matrix
|
|
void zeroOffDiag(float (&cov_mat)[_k_num_states][_k_num_states], uint8_t first, uint8_t last);
|
|
|
|
// zero the specified range of off diagonals in the state covariance matrix
|
|
// set the diagonals to the supplied value
|
|
void setDiag(float (&cov_mat)[_k_num_states][_k_num_states], uint8_t first, uint8_t last, float variance);
|
|
|
|
// calculate the measurement variance for the optical flow sensor
|
|
float calcOptFlowMeasVar();
|
|
|
|
// rotate quaternion covariances into variances for an equivalent rotation vector
|
|
Vector3f calcRotVecVariances();
|
|
|
|
// initialise the quaternion covariances using rotation vector variances
|
|
void initialiseQuatCovariances(Vector3f &rot_vec_var);
|
|
|
|
// perform a limited reset of the magnetic field state covariances
|
|
void resetMagCovariance();
|
|
|
|
// perform a limited reset of the wind state covariances
|
|
void resetWindCovariance();
|
|
|
|
// perform a reset of the wind states
|
|
void resetWindStates();
|
|
|
|
// check that the range finder data is continuous
|
|
void checkRangeDataContinuity();
|
|
|
|
};
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