px4-firmware/EKF/sensor_range_finder.cpp

140 lines
4.5 KiB
C++

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/**
* @file sensor_range_finder.cpp
*
* @author Mathieu Bresciani <brescianimathieu@gmail.com>
*
*/
#include "sensor_range_finder.hpp"
namespace estimator
{
namespace sensor
{
void SensorRangeFinder::runChecks(const uint64_t current_time_us, const Dcmf &R_to_earth)
{
updateSensorToEarthRotation(R_to_earth);
updateValidity(current_time_us);
}
void SensorRangeFinder::updateSensorToEarthRotation(const Dcmf &R_to_earth)
{
// calculate 2,2 element of rotation matrix from sensor frame to earth frame
// this is required for use of range finder and flow data
_cos_tilt_rng_to_earth = R_to_earth(2, 0) * _sin_pitch_offset + R_to_earth(2, 2) * _cos_pitch_offset;
}
void SensorRangeFinder::updateValidity(uint64_t current_time_us)
{
updateDtDataLpf(current_time_us);
if (isSampleOutOfDate(current_time_us) || !isDataContinuous()) {
_is_sample_valid = false;
return;
}
// Don't run the checks unless we have retrieved new data from the buffer
if (_is_sample_ready) {
_is_sample_valid = false;
if (_sample.quality == 0) {
_time_bad_quality_us = current_time_us;
} else if (current_time_us - _time_bad_quality_us > _quality_hyst_us) {
// We did not receive bad quality data for some time
if (isTiltOk() && isDataInRange()) {
updateStuckCheck();
if (!_is_stuck) {
_is_sample_valid = true;
_time_last_valid_us = _sample.time_us;
}
}
}
}
}
void SensorRangeFinder::updateDtDataLpf(uint64_t current_time_us)
{
// Calculate a first order IIR low-pass filtered time of arrival between samples using a 2 second time constant.
float alpha = 0.5f * _dt_update;
_dt_data_lpf = _dt_data_lpf * (1.0f - alpha) + alpha * (current_time_us - _sample.time_us);
// Apply spike protection to the filter state.
_dt_data_lpf = fminf(_dt_data_lpf, 4e6f);
}
inline bool SensorRangeFinder::isSampleOutOfDate(uint64_t current_time_us) const
{
return (current_time_us - _sample.time_us) > 2 * RNG_MAX_INTERVAL;
}
inline bool SensorRangeFinder::isDataInRange() const
{
return (_sample.rng >= _rng_valid_min_val) && (_sample.rng <= _rng_valid_max_val);
}
void SensorRangeFinder::updateStuckCheck()
{
// Check for "stuck" range finder measurements when range was not valid for certain period
// This handles a failure mode observed with some lidar sensors
if (((_sample.time_us - _time_last_valid_us) > (uint64_t)10e6)) {
// require a variance of rangefinder values to check for "stuck" measurements
if (_stuck_max_val - _stuck_min_val > _stuck_threshold) {
_stuck_min_val = 0.0f;
_stuck_max_val = 0.0f;
_is_stuck = false;
} else {
if (_sample.rng > _stuck_max_val) {
_stuck_max_val = _sample.rng;
}
if (_stuck_min_val < 0.1f || _sample.rng < _stuck_min_val) {
_stuck_min_val = _sample.rng;
}
_is_stuck = true;
}
}
}
} // namespace sensor
} // namespace estimator