forked from Archive/PX4-Autopilot
237 lines
10 KiB
C++
237 lines
10 KiB
C++
/****************************************************************************
|
|
*
|
|
* Copyright (c) 2013 Estimation and Control Library (ECL). All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
* 3. Neither the name ECL nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/**
|
|
* @file gps_checks.cpp
|
|
* Perform pre-flight and in-flight GPS quality checks
|
|
*
|
|
* @author Paul Riseborough <p_riseborough@live.com.au>
|
|
*
|
|
*/
|
|
|
|
#include "ekf.h"
|
|
|
|
#include <ecl.h>
|
|
#include <geo_lookup/geo_mag_declination.h>
|
|
#include <mathlib/mathlib.h>
|
|
|
|
// GPS pre-flight check bit locations
|
|
#define MASK_GPS_NSATS (1<<0)
|
|
#define MASK_GPS_PDOP (1<<1)
|
|
#define MASK_GPS_HACC (1<<2)
|
|
#define MASK_GPS_VACC (1<<3)
|
|
#define MASK_GPS_SACC (1<<4)
|
|
#define MASK_GPS_HDRIFT (1<<5)
|
|
#define MASK_GPS_VDRIFT (1<<6)
|
|
#define MASK_GPS_HSPD (1<<7)
|
|
#define MASK_GPS_VSPD (1<<8)
|
|
|
|
bool Ekf::collect_gps(const gps_message &gps)
|
|
{
|
|
// Run GPS checks always
|
|
_gps_checks_passed = gps_is_good(gps);
|
|
if (!_NED_origin_initialised && _gps_checks_passed) {
|
|
// If we have good GPS data set the origin's WGS-84 position to the last gps fix
|
|
const double lat = gps.lat / 1.0e7;
|
|
const double lon = gps.lon / 1.0e7;
|
|
map_projection_init_timestamped(&_pos_ref, lat, lon, _time_last_imu);
|
|
|
|
// if we are already doing aiding, correct for the change in position since the EKF started navigationg
|
|
if (_control_status.flags.opt_flow || _control_status.flags.gps || _control_status.flags.ev_pos || _control_status.flags.ev_vel) {
|
|
double est_lat, est_lon;
|
|
map_projection_reproject(&_pos_ref, -_state.pos(0), -_state.pos(1), &est_lat, &est_lon);
|
|
map_projection_init_timestamped(&_pos_ref, est_lat, est_lon, _time_last_imu);
|
|
}
|
|
|
|
// Take the current GPS height and subtract the filter height above origin to estimate the GPS height of the origin
|
|
_gps_alt_ref = 1e-3f * (float)gps.alt + _state.pos(2);
|
|
_NED_origin_initialised = true;
|
|
_earth_rate_NED = calcEarthRateNED((float)_pos_ref.lat_rad);
|
|
_last_gps_origin_time_us = _time_last_imu;
|
|
|
|
// set the magnetic field data returned by the geo library using the current GPS position
|
|
_mag_declination_gps = math::radians(get_mag_declination(lat, lon));
|
|
_mag_inclination_gps = math::radians(get_mag_inclination(lat, lon));
|
|
_mag_strength_gps = 0.01f * get_mag_strength(lat, lon);
|
|
|
|
// request a reset of the yaw using the new declination
|
|
_mag_yaw_reset_req = true;
|
|
// save the horizontal and vertical position uncertainty of the origin
|
|
_gps_origin_eph = gps.eph;
|
|
_gps_origin_epv = gps.epv;
|
|
|
|
// if the user has selected GPS as the primary height source, switch across to using it
|
|
|
|
if (_params.vdist_sensor_type == VDIST_SENSOR_GPS) {
|
|
ECL_INFO_TIMESTAMPED("GPS checks passed (WGS-84 origin set, using GPS height)");
|
|
setControlGPSHeight();
|
|
// zero the sensor offset
|
|
_hgt_sensor_offset = 0.0f;
|
|
} else {
|
|
ECL_INFO_TIMESTAMPED("GPS checks passed (WGS-84 origin set)");
|
|
}
|
|
}
|
|
|
|
// start collecting GPS if there is a 3D fix and the NED origin has been set
|
|
return _NED_origin_initialised && (gps.fix_type >= 3);
|
|
}
|
|
|
|
/*
|
|
* Return true if the GPS solution quality is adequate to set an origin for the EKF
|
|
* and start GPS aiding.
|
|
* All activated checks must pass for 10 seconds.
|
|
* Checks are activated using the EKF2_GPS_CHECK bitmask parameter
|
|
* Checks are adjusted using the EKF2_REQ_* parameters
|
|
*/
|
|
bool Ekf::gps_is_good(const gps_message &gps)
|
|
{
|
|
// Check the fix type
|
|
_gps_check_fail_status.flags.fix = (gps.fix_type < 3);
|
|
|
|
// Check the number of satellites
|
|
_gps_check_fail_status.flags.nsats = (gps.nsats < _params.req_nsats);
|
|
|
|
// Check the position dilution of precision
|
|
_gps_check_fail_status.flags.pdop = (gps.pdop > _params.req_pdop);
|
|
|
|
// Check the reported horizontal and vertical position accuracy
|
|
_gps_check_fail_status.flags.hacc = (gps.eph > _params.req_hacc);
|
|
_gps_check_fail_status.flags.vacc = (gps.epv > _params.req_vacc);
|
|
|
|
// Check the reported speed accuracy
|
|
_gps_check_fail_status.flags.sacc = (gps.sacc > _params.req_sacc);
|
|
|
|
// check if GPS quality is degraded
|
|
_gps_error_norm = fmaxf((gps.eph / _params.req_hacc) , (gps.epv / _params.req_vacc));
|
|
_gps_error_norm = fmaxf(_gps_error_norm , (gps.sacc / _params.req_sacc));
|
|
|
|
// Calculate time lapsed since last update, limit to prevent numerical errors and calculate a lowpass filter coefficient
|
|
const float filt_time_const = 10.0f;
|
|
const float dt = fminf(fmaxf(float(_time_last_imu - _gps_pos_prev.timestamp) * 1e-6f, 0.001f), filt_time_const);
|
|
const float filter_coef = dt / filt_time_const;
|
|
|
|
// The following checks are only valid when the vehicle is at rest
|
|
const double lat = gps.lat * 1.0e-7;
|
|
const double lon = gps.lon * 1.0e-7;
|
|
if (!_control_status.flags.in_air && _vehicle_at_rest) {
|
|
// Calculate position movement since last measurement
|
|
float delta_pos_n = 0.0f;
|
|
float delta_pos_e = 0.0f;
|
|
|
|
// calculate position movement since last GPS fix
|
|
if (_gps_pos_prev.timestamp > 0) {
|
|
map_projection_project(&_gps_pos_prev, lat, lon, &delta_pos_n, &delta_pos_e);
|
|
|
|
} else {
|
|
// no previous position has been set
|
|
map_projection_init_timestamped(&_gps_pos_prev, lat, lon, _time_last_imu);
|
|
_gps_alt_prev = 1e-3f * (float)gps.alt;
|
|
}
|
|
|
|
// Calculate the horizontal and vertical drift velocity components and limit to 10x the threshold
|
|
const Vector3f vel_limit(_params.req_hdrift, _params.req_hdrift, _params.req_vdrift);
|
|
Vector3f pos_derived(delta_pos_n, delta_pos_e, (_gps_alt_prev - 1e-3f * (float)gps.alt));
|
|
pos_derived = matrix::constrain(pos_derived / dt, -10.0f * vel_limit, 10.0f * vel_limit);
|
|
|
|
// Apply a low pass filter
|
|
_gps_pos_deriv_filt = pos_derived * filter_coef + _gps_pos_deriv_filt * (1.0f - filter_coef);
|
|
|
|
// Calculate the horizontal drift speed and fail if too high
|
|
_gps_drift_metrics[0] = Vector2f(_gps_pos_deriv_filt.xy()).norm();
|
|
_gps_check_fail_status.flags.hdrift = (_gps_drift_metrics[0] > _params.req_hdrift);
|
|
|
|
// Fail if the vertical drift speed is too high
|
|
_gps_drift_metrics[1] = fabsf(_gps_pos_deriv_filt(2));
|
|
_gps_check_fail_status.flags.vdrift = (_gps_drift_metrics[1] > _params.req_vdrift);
|
|
|
|
// Check the magnitude of the filtered horizontal GPS velocity
|
|
Vector2f gps_velNE = matrix::constrain(Vector2f(gps.vel_ned.xy()),
|
|
-10.0f * _params.req_hdrift,
|
|
10.0f * _params.req_hdrift);
|
|
_gps_velNE_filt = gps_velNE * filter_coef + _gps_velNE_filt * (1.0f - filter_coef);
|
|
_gps_drift_metrics[2] = _gps_velNE_filt.norm();
|
|
_gps_check_fail_status.flags.hspeed = (_gps_drift_metrics[2] > _params.req_hdrift);
|
|
|
|
_gps_drift_updated = true;
|
|
|
|
} else if (_control_status.flags.in_air) {
|
|
// These checks are always declared as passed when flying
|
|
// If on ground and moving, the last result before movement commenced is kept
|
|
_gps_check_fail_status.flags.hdrift = false;
|
|
_gps_check_fail_status.flags.vdrift = false;
|
|
_gps_check_fail_status.flags.hspeed = false;
|
|
_gps_drift_updated = false;
|
|
|
|
} else {
|
|
// This is the case where the vehicle is on ground and IMU movement is blocking the drift calculation
|
|
_gps_drift_updated = true;
|
|
|
|
}
|
|
|
|
// save GPS fix for next time
|
|
map_projection_init_timestamped(&_gps_pos_prev, lat, lon, _time_last_imu);
|
|
_gps_alt_prev = 1e-3f * (float)gps.alt;
|
|
|
|
// Check the filtered difference between GPS and EKF vertical velocity
|
|
float vz_diff_limit = 10.0f * _params.req_vdrift;
|
|
float vertVel = fminf(fmaxf((gps.vel_ned(2) - _state.vel(2)), -vz_diff_limit), vz_diff_limit);
|
|
_gps_velD_diff_filt = vertVel * filter_coef + _gps_velD_diff_filt * (1.0f - filter_coef);
|
|
_gps_check_fail_status.flags.vspeed = (fabsf(_gps_velD_diff_filt) > _params.req_vdrift);
|
|
|
|
// assume failed first time through
|
|
if (_last_gps_fail_us == 0) {
|
|
_last_gps_fail_us = _time_last_imu;
|
|
}
|
|
|
|
// if any user selected checks have failed, record the fail time
|
|
if (
|
|
_gps_check_fail_status.flags.fix ||
|
|
(_gps_check_fail_status.flags.nsats && (_params.gps_check_mask & MASK_GPS_NSATS)) ||
|
|
(_gps_check_fail_status.flags.pdop && (_params.gps_check_mask & MASK_GPS_PDOP)) ||
|
|
(_gps_check_fail_status.flags.hacc && (_params.gps_check_mask & MASK_GPS_HACC)) ||
|
|
(_gps_check_fail_status.flags.vacc && (_params.gps_check_mask & MASK_GPS_VACC)) ||
|
|
(_gps_check_fail_status.flags.sacc && (_params.gps_check_mask & MASK_GPS_SACC)) ||
|
|
(_gps_check_fail_status.flags.hdrift && (_params.gps_check_mask & MASK_GPS_HDRIFT)) ||
|
|
(_gps_check_fail_status.flags.vdrift && (_params.gps_check_mask & MASK_GPS_VDRIFT)) ||
|
|
(_gps_check_fail_status.flags.hspeed && (_params.gps_check_mask & MASK_GPS_HSPD)) ||
|
|
(_gps_check_fail_status.flags.vspeed && (_params.gps_check_mask & MASK_GPS_VSPD))
|
|
) {
|
|
_last_gps_fail_us = _time_last_imu;
|
|
} else {
|
|
_last_gps_pass_us = _time_last_imu;
|
|
}
|
|
|
|
// continuous period without fail of x seconds required to return a healthy status
|
|
return _time_last_imu - _last_gps_fail_us > (uint64_t)_min_gps_health_time_us;
|
|
}
|