/**************************************************************************** * * 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 estimator_interface.cpp * Definition of base class for attitude estimators * * @author Roman Bast * @author Paul Riseborough * @author Siddharth B Purohit */ #include "estimator_interface.h" #include #include // Accumulate imu data and store to buffer at desired rate void EstimatorInterface::setIMUData(const imuSample &imu_sample) { // TODO: resolve misplaced responsibility if (!_initialised) { init(imu_sample.time_us); _initialised = true; } const float dt = math::constrain((imu_sample.time_us - _time_last_imu) / 1e6f, 1.0e-4f, 0.02f); _time_last_imu = imu_sample.time_us; if (_time_last_imu > 0) { _dt_imu_avg = 0.8f * _dt_imu_avg + 0.2f * dt; } _newest_high_rate_imu_sample = imu_sample; // Do not change order of computeVibrationMetric and checkIfVehicleAtRest computeVibrationMetric(); _control_status.flags.vehicle_at_rest = checkIfVehicleAtRest(dt); const bool new_downsampled_imu_sample_ready = _imu_down_sampler.update(_newest_high_rate_imu_sample); _imu_updated = new_downsampled_imu_sample_ready; // accumulate and down-sample imu data and push to the buffer when new downsampled data becomes available if (new_downsampled_imu_sample_ready) { _imu_buffer.push(_imu_down_sampler.getDownSampledImuAndTriggerReset()); // get the oldest data from the buffer _imu_sample_delayed = _imu_buffer.get_oldest(); // calculate the minimum interval between observations required to guarantee no loss of data // this will occur if data is overwritten before its time stamp falls behind the fusion time horizon _min_obs_interval_us = (_newest_high_rate_imu_sample.time_us - _imu_sample_delayed.time_us) / (_obs_buffer_length - 1); setDragData(); } } void EstimatorInterface::computeVibrationMetric() { // calculate a metric which indicates the amount of coning vibration Vector3f temp = _newest_high_rate_imu_sample.delta_ang % _delta_ang_prev; _vibe_metrics(0) = 0.99f * _vibe_metrics(0) + 0.01f * temp.norm(); // calculate a metric which indicates the amount of high frequency gyro vibration temp = _newest_high_rate_imu_sample.delta_ang - _delta_ang_prev; _delta_ang_prev = _newest_high_rate_imu_sample.delta_ang; _vibe_metrics(1) = 0.99f * _vibe_metrics(1) + 0.01f * temp.norm(); // calculate a metric which indicates the amount of high frequency accelerometer vibration temp = _newest_high_rate_imu_sample.delta_vel - _delta_vel_prev; _delta_vel_prev = _newest_high_rate_imu_sample.delta_vel; _vibe_metrics(2) = 0.99f * _vibe_metrics(2) + 0.01f * temp.norm(); } bool EstimatorInterface::checkIfVehicleAtRest(float dt) { // detect if the vehicle is not moving when on ground if (!_control_status.flags.in_air) { if ((_vibe_metrics(1) * 4.0E4f > _params.is_moving_scaler) || (_vibe_metrics(2) * 2.1E2f > _params.is_moving_scaler) || ((_newest_high_rate_imu_sample.delta_ang.norm() / dt) > 0.05f * _params.is_moving_scaler)) { _time_last_move_detect_us = _newest_high_rate_imu_sample.time_us; } return ((_newest_high_rate_imu_sample.time_us - _time_last_move_detect_us) > (uint64_t)1E6); } else { _time_last_move_detect_us = _newest_high_rate_imu_sample.time_us; return false; } } void EstimatorInterface::setMagData(const magSample &mag_sample) { if (!_initialised || _mag_buffer_fail) { return; } // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_mag_buffer.get_length() < _obs_buffer_length) { _mag_buffer_fail = !_mag_buffer.allocate(_obs_buffer_length); if (_mag_buffer_fail) { printBufferAllocationFailed("mag"); return; } } // downsample to highest possible sensor rate // by taking the average of incoming sample _mag_sample_count++; _mag_data_sum += mag_sample.mag; _mag_timestamp_sum += mag_sample.time_us / 1000; // Dividing by 1000 to avoid overflow // limit data rate to prevent data being lost if ((mag_sample.time_us - _time_last_mag) > _min_obs_interval_us) { _time_last_mag = mag_sample.time_us; magSample mag_sample_new; // Use the time in the middle of the downsampling interval for the sample mag_sample_new.time_us = 1000 * (_mag_timestamp_sum / _mag_sample_count); mag_sample_new.time_us -= _params.mag_delay_ms * 1000; mag_sample_new.time_us -= FILTER_UPDATE_PERIOD_MS * 1000 / 2; mag_sample_new.mag = _mag_data_sum / _mag_sample_count; _mag_buffer.push(mag_sample_new); _mag_sample_count = 0; _mag_data_sum.setZero(); _mag_timestamp_sum = 0; } } void EstimatorInterface::setGpsData(const gps_message &gps) { if (!_initialised || _gps_buffer_fail) { return; } // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_gps_buffer.get_length() < _obs_buffer_length) { _gps_buffer_fail = !_gps_buffer.allocate(_obs_buffer_length); if (_gps_buffer_fail) { printBufferAllocationFailed("GPS"); return; } } // limit data rate to prevent data being lost bool need_gps = (_params.fusion_mode & MASK_USE_GPS) || (_params.vdist_sensor_type == VDIST_SENSOR_GPS); // TODO: remove checks that are not timing related if (((gps.time_usec - _time_last_gps) > _min_obs_interval_us) && need_gps && gps.fix_type > 2) { _time_last_gps = gps.time_usec; gpsSample gps_sample_new; gps_sample_new.time_us = gps.time_usec - _params.gps_delay_ms * 1000; gps_sample_new.time_us -= FILTER_UPDATE_PERIOD_MS * 1000 / 2; gps_sample_new.vel = gps.vel_ned; _gps_speed_valid = gps.vel_ned_valid; gps_sample_new.sacc = gps.sacc; gps_sample_new.hacc = gps.eph; gps_sample_new.vacc = gps.epv; gps_sample_new.hgt = (float)gps.alt * 1e-3f; gps_sample_new.yaw = gps.yaw; if (ISFINITE(gps.yaw_offset)) { _gps_yaw_offset = gps.yaw_offset; } else { _gps_yaw_offset = 0.0f; } // Only calculate the relative position if the WGS-84 location of the origin is set if (collect_gps(gps)) { float lpos_x = 0.0f; float lpos_y = 0.0f; map_projection_project(&_pos_ref, (gps.lat / 1.0e7), (gps.lon / 1.0e7), &lpos_x, &lpos_y); gps_sample_new.pos(0) = lpos_x; gps_sample_new.pos(1) = lpos_y; } else { gps_sample_new.pos(0) = 0.0f; gps_sample_new.pos(1) = 0.0f; } _gps_buffer.push(gps_sample_new); } } void EstimatorInterface::setBaroData(const baroSample &baro_sample) { if (!_initialised || _baro_buffer_fail) { return; } // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_baro_buffer.get_length() < _obs_buffer_length) { _baro_buffer_fail = !_baro_buffer.allocate(_obs_buffer_length); if (_baro_buffer_fail) { printBufferAllocationFailed("baro"); return; } } // downsample to highest possible sensor rate // by baro data by taking the average of incoming sample _baro_sample_count++; _baro_alt_sum += baro_sample.hgt; _baro_timestamp_sum += baro_sample.time_us / 1000; // Dividing by 1000 to avoid overflow // limit data rate to prevent data being lost if ((baro_sample.time_us - _time_last_baro) > _min_obs_interval_us) { _time_last_baro = baro_sample.time_us; const float baro_alt_avg = _baro_alt_sum / (float)_baro_sample_count; baroSample baro_sample_new; baro_sample_new.hgt = compensateBaroForDynamicPressure(baro_alt_avg); // Use the time in the middle of the downsampling interval for the sample baro_sample_new.time_us = 1000 * (_baro_timestamp_sum / _baro_sample_count); baro_sample_new.time_us -= _params.baro_delay_ms * 1000; baro_sample_new.time_us -= FILTER_UPDATE_PERIOD_MS * 1000 / 2; _baro_buffer.push(baro_sample_new); _baro_sample_count = 0; _baro_alt_sum = 0.0f; _baro_timestamp_sum = 0; } } void EstimatorInterface::setAirspeedData(const airspeedSample &airspeed_sample) { if (!_initialised || _airspeed_buffer_fail) { return; } // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_airspeed_buffer.get_length() < _obs_buffer_length) { _airspeed_buffer_fail = !_airspeed_buffer.allocate(_obs_buffer_length); if (_airspeed_buffer_fail) { printBufferAllocationFailed("airspeed"); return; } } // limit data rate to prevent data being lost if ((airspeed_sample.time_us - _time_last_airspeed) > _min_obs_interval_us) { _time_last_airspeed = airspeed_sample.time_us; airspeedSample airspeed_sample_new = airspeed_sample; airspeed_sample_new.time_us -= _params.airspeed_delay_ms * 1000; airspeed_sample_new.time_us -= FILTER_UPDATE_PERIOD_MS * 1000 / 2; _airspeed_buffer.push(airspeed_sample_new); } } void EstimatorInterface::setRangeData(const rangeSample& range_sample) { if (!_initialised || _range_buffer_fail) { return; } // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_range_buffer.get_length() < _obs_buffer_length) { _range_buffer_fail = !_range_buffer.allocate(_obs_buffer_length); if (_range_buffer_fail) { printBufferAllocationFailed("range"); return; } } // limit data rate to prevent data being lost if ((range_sample.time_us - _time_last_range) > _min_obs_interval_us) { _time_last_range = range_sample.time_us; rangeSample range_sample_new = range_sample; range_sample_new.time_us -= _params.range_delay_ms * 1000; range_sample_new.time_us -= FILTER_UPDATE_PERIOD_MS * 1000 / 2; _range_buffer.push(range_sample_new); } } void EstimatorInterface::setOpticalFlowData(const flowSample& flow) { if (!_initialised || _flow_buffer_fail) { return; } // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_flow_buffer.get_length() < _imu_buffer_length) { _flow_buffer_fail = !_flow_buffer.allocate(_imu_buffer_length); if (_flow_buffer_fail) { printBufferAllocationFailed("flow"); return; } } // limit data rate to prevent data being lost if ((flow.time_us - _time_last_optflow) > _min_obs_interval_us) { // check if enough integration time and fail if integration time is less than 50% // of min arrival interval because too much data is being lost float delta_time = flow.dt; // in seconds const float delta_time_min = 0.5e-6f * (float)_min_obs_interval_us; bool delta_time_good = delta_time >= delta_time_min; bool flow_magnitude_good = true; if (delta_time_good) { // check magnitude is within sensor limits // use this to prevent use of a saturated flow sensor // when there are other aiding sources available const float flow_rate_magnitude = flow.flow_xy_rad.norm() / delta_time; flow_magnitude_good = (flow_rate_magnitude <= _flow_max_rate); } else { // protect against overflow caused by division with very small delta_time delta_time = delta_time_min; } const bool relying_on_flow = !isOtherSourceOfHorizontalAidingThan(_control_status.flags.opt_flow); const bool flow_quality_good = (flow.quality >= _params.flow_qual_min); // Check data validity and write to buffers // Invalid flow data is allowed when on ground and is handled as a special case in controlOpticalFlowFusion() bool use_flow_data_to_navigate = delta_time_good && flow_quality_good && (flow_magnitude_good || relying_on_flow); if (use_flow_data_to_navigate || (!_control_status.flags.in_air && relying_on_flow)) { _time_last_optflow = flow.time_us; flowSample optflow_sample_new = flow; optflow_sample_new.time_us -= _params.flow_delay_ms * 1000; optflow_sample_new.time_us -= FILTER_UPDATE_PERIOD_MS * 1000 / 2; optflow_sample_new.dt = delta_time; _flow_buffer.push(optflow_sample_new); } } } // set attitude and position data derived from an external vision system void EstimatorInterface::setExtVisionData(const extVisionSample& evdata) { if (!_initialised || _ev_buffer_fail) { return; } // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_ext_vision_buffer.get_length() < _obs_buffer_length) { _ev_buffer_fail = !_ext_vision_buffer.allocate(_obs_buffer_length); if (_ev_buffer_fail) { printBufferAllocationFailed("vision"); return; } } // limit data rate to prevent data being lost if ((evdata.time_us - _time_last_ext_vision) > _min_obs_interval_us) { _time_last_ext_vision = evdata.time_us; extVisionSample ev_sample_new = evdata; // calculate the system time-stamp for the mid point of the integration period ev_sample_new.time_us -= _params.ev_delay_ms * 1000; ev_sample_new.time_us -= FILTER_UPDATE_PERIOD_MS * 1000 / 2; _ext_vision_buffer.push(ev_sample_new); } } void EstimatorInterface::setAuxVelData(const auxVelSample& auxvel_sample) { if (!_initialised || _auxvel_buffer_fail) { return; } // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_auxvel_buffer.get_length() < _obs_buffer_length) { _auxvel_buffer_fail = !_auxvel_buffer.allocate(_obs_buffer_length); if (_auxvel_buffer_fail) { printBufferAllocationFailed("aux vel"); return; } } // limit data rate to prevent data being lost if ((auxvel_sample.time_us - _time_last_auxvel) > _min_obs_interval_us) { _time_last_auxvel = auxvel_sample.time_us; auxVelSample auxvel_sample_new = auxvel_sample; auxvel_sample_new.time_us -= _params.auxvel_delay_ms * 1000; auxvel_sample_new.time_us -= FILTER_UPDATE_PERIOD_MS * 1000 / 2; _auxvel_buffer.push(auxvel_sample_new); } } void EstimatorInterface::setDragData() { // down-sample the drag specific force data by accumulating and calculating the mean when // sufficient samples have been collected if ((_params.fusion_mode & MASK_USE_DRAG) && !_drag_buffer_fail) { // Allocate the required buffer size if not previously done // Do not retry if allocation has failed previously if (_drag_buffer.get_length() < _obs_buffer_length) { _drag_buffer_fail = !_drag_buffer.allocate(_obs_buffer_length); if (_drag_buffer_fail) { printBufferAllocationFailed("drag"); return; } } _drag_sample_count ++; // note acceleration is accumulated as a delta velocity _drag_down_sampled.accelXY(0) += _newest_high_rate_imu_sample.delta_vel(0); _drag_down_sampled.accelXY(1) += _newest_high_rate_imu_sample.delta_vel(1); _drag_down_sampled.time_us += _newest_high_rate_imu_sample.time_us; _drag_sample_time_dt += _newest_high_rate_imu_sample.delta_vel_dt; // calculate the downsample ratio for drag specific force data uint8_t min_sample_ratio = (uint8_t) ceilf((float)_imu_buffer_length / _obs_buffer_length); if (min_sample_ratio < 5) { min_sample_ratio = 5; } // calculate and store means from accumulated values if (_drag_sample_count >= min_sample_ratio) { // note conversion from accumulated delta velocity to acceleration _drag_down_sampled.accelXY(0) /= _drag_sample_time_dt; _drag_down_sampled.accelXY(1) /= _drag_sample_time_dt; _drag_down_sampled.time_us /= _drag_sample_count; // write to buffer _drag_buffer.push(_drag_down_sampled); // reset accumulators _drag_sample_count = 0; _drag_down_sampled.accelXY.zero(); _drag_down_sampled.time_us = 0; _drag_sample_time_dt = 0.0f; } } } bool EstimatorInterface::initialise_interface(uint64_t timestamp) { // find the maximum time delay the buffers are required to handle uint16_t max_time_delay_ms = math::max(_params.mag_delay_ms, math::max(_params.range_delay_ms, math::max(_params.gps_delay_ms, math::max(_params.flow_delay_ms, math::max(_params.ev_delay_ms, math::max(_params.auxvel_delay_ms, math::max(_params.min_delay_ms, math::max(_params.airspeed_delay_ms, _params.baro_delay_ms)))))))); // calculate the IMU buffer length required to accomodate the maximum delay with some allowance for jitter _imu_buffer_length = (max_time_delay_ms / FILTER_UPDATE_PERIOD_MS) + 1; // set the observation buffer length to handle the minimum time of arrival between observations in combination // with the worst case delay from current time to ekf fusion time // allow for worst case 50% extension of the ekf fusion time horizon delay due to timing jitter const uint16_t ekf_delay_ms = max_time_delay_ms + (int)(ceilf((float)max_time_delay_ms * 0.5f)); _obs_buffer_length = (ekf_delay_ms / _params.sensor_interval_min_ms) + 1; // limit to be no longer than the IMU buffer (we can't process data faster than the EKF prediction rate) _obs_buffer_length = math::min(_obs_buffer_length, _imu_buffer_length); if (!(_imu_buffer.allocate(_imu_buffer_length) && _output_buffer.allocate(_imu_buffer_length) && _output_vert_buffer.allocate(_imu_buffer_length))) { printBufferAllocationFailed(""); unallocate_buffers(); return false; } _imu_sample_delayed.time_us = timestamp; _imu_sample_delayed.delta_vel_clipping[0] = false; _imu_sample_delayed.delta_vel_clipping[1] = false; _imu_sample_delayed.delta_vel_clipping[2] = false; _fault_status.value = 0; return true; } void EstimatorInterface::unallocate_buffers() { _imu_buffer.unallocate(); _gps_buffer.unallocate(); _mag_buffer.unallocate(); _baro_buffer.unallocate(); _range_buffer.unallocate(); _airspeed_buffer.unallocate(); _flow_buffer.unallocate(); _ext_vision_buffer.unallocate(); _output_buffer.unallocate(); _output_vert_buffer.unallocate(); _drag_buffer.unallocate(); _auxvel_buffer.unallocate(); } bool EstimatorInterface::local_position_is_valid() { // return true if we are not doing unconstrained free inertial navigation return !_deadreckon_time_exceeded; } bool EstimatorInterface::isOnlyActiveSourceOfHorizontalAiding(const bool aiding_flag) const { return aiding_flag && !isOtherSourceOfHorizontalAidingThan(aiding_flag); } bool EstimatorInterface::isOtherSourceOfHorizontalAidingThan(const bool aiding_flag) const { const int nb_sources = getNumberOfActiveHorizontalAidingSources(); return aiding_flag ? nb_sources > 1 : nb_sources > 0; } int EstimatorInterface::getNumberOfActiveHorizontalAidingSources() const { return int(_control_status.flags.gps) + int(_control_status.flags.opt_flow) + int(_control_status.flags.ev_pos) + int(_control_status.flags.ev_vel); } bool EstimatorInterface::isHorizontalAidingActive() const { return getNumberOfActiveHorizontalAidingSources() > 0; } void EstimatorInterface::printBufferAllocationFailed(const char * buffer_name) { if(buffer_name) { ECL_ERR("%s buffer allocation failed", buffer_name); } } void EstimatorInterface::print_status() { ECL_INFO("local position valid: %s", local_position_is_valid() ? "yes" : "no"); ECL_INFO("global position valid: %s", global_position_is_valid() ? "yes" : "no"); ECL_INFO("imu buffer: %d (%d Bytes)", _imu_buffer.get_length(), _imu_buffer.get_total_size()); ECL_INFO("gps buffer: %d (%d Bytes)", _gps_buffer.get_length(), _gps_buffer.get_total_size()); ECL_INFO("mag buffer: %d (%d Bytes)", _mag_buffer.get_length(), _mag_buffer.get_total_size()); ECL_INFO("baro buffer: %d (%d Bytes)", _baro_buffer.get_length(), _baro_buffer.get_total_size()); ECL_INFO("range buffer: %d (%d Bytes)", _range_buffer.get_length(), _range_buffer.get_total_size()); ECL_INFO("airspeed buffer: %d (%d Bytes)", _airspeed_buffer.get_length(), _airspeed_buffer.get_total_size()); ECL_INFO("flow buffer: %d (%d Bytes)", _flow_buffer.get_length(), _flow_buffer.get_total_size()); ECL_INFO("vision buffer: %d (%d Bytes)", _ext_vision_buffer.get_length(), _ext_vision_buffer.get_total_size()); ECL_INFO("output buffer: %d (%d Bytes)", _output_buffer.get_length(), _output_buffer.get_total_size()); ECL_INFO("output vert buffer: %d (%d Bytes)", _output_vert_buffer.get_length(), _output_vert_buffer.get_total_size()); ECL_INFO("drag buffer: %d (%d Bytes)", _drag_buffer.get_length(), _drag_buffer.get_total_size()); }