mirror of https://github.com/ArduPilot/ardupilot
AP_NavEKF3: Relative Error based Lane-Switching
Improvments to the lane selection logic, we accumulate error for each EKF lane relative to the primary for a more robust core selection
This commit is contained in:
parent
56cbcb42ee
commit
d7edc946b6
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@ -639,6 +639,14 @@ const AP_Param::GroupInfo NavEKF3::var_info[] = {
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// @RebootRequired: True
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// @RebootRequired: True
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AP_GROUPINFO("GSF_RST_MAX", 60, NavEKF3, _gsfResetMaxCount, 2),
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AP_GROUPINFO("GSF_RST_MAX", 60, NavEKF3, _gsfResetMaxCount, 2),
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// @Param: ERR_THRESH
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// @DisplayName: EKF3 Lane Relative Error Sensitivity Threshold
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// @Description: lanes have to be consistently better than the primary by at least this threshold to reduce their overall relativeCoreError, lowering this makes lane switching more sensitive to smaller error differences
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// @Range: 0.05 1
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// @Increment: 0.05
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// @User: Advanced
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AP_GROUPINFO("ERR_THRESH", 61, NavEKF3, _err_thresh, 0.2),
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AP_GROUPEND
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AP_GROUPEND
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};
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};
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@ -703,14 +711,14 @@ bool NavEKF3::InitialiseFilter(void)
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_imuMask.set(_imuMask.get() & mask);
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_imuMask.set(_imuMask.get() & mask);
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// initialise the setup variables
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// initialise the setup variables
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for (uint8_t i=0; i<7; i++) {
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for (uint8_t i=0; i<MAX_EKF_CORES; i++) {
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coreSetupRequired[i] = false;
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coreSetupRequired[i] = false;
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coreImuIndex[i] = 0;
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coreImuIndex[i] = 0;
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}
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}
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num_cores = 0;
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num_cores = 0;
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// count IMUs from mask
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// count IMUs from mask
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for (uint8_t i=0; i<7; i++) {
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for (uint8_t i=0; i<MAX_EKF_CORES; i++) {
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if (_imuMask & (1U<<i)) {
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if (_imuMask & (1U<<i)) {
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coreSetupRequired[num_cores] = true;
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coreSetupRequired[num_cores] = true;
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coreImuIndex[num_cores] = i;
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coreImuIndex[num_cores] = i;
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@ -720,7 +728,7 @@ bool NavEKF3::InitialiseFilter(void)
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// check if there is enough memory to create the EKF cores
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// check if there is enough memory to create the EKF cores
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if (hal.util->available_memory() < sizeof(NavEKF3_core)*num_cores + 4096) {
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if (hal.util->available_memory() < sizeof(NavEKF3_core)*num_cores + 4096) {
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gcs().send_text(MAV_SEVERITY_CRITICAL, "NavEKF3: not enough memory");
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gcs().send_text(MAV_SEVERITY_CRITICAL, "EKF3 not enough memory");
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_enable.set(0);
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_enable.set(0);
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return false;
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return false;
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}
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}
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@ -729,7 +737,7 @@ bool NavEKF3::InitialiseFilter(void)
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core = (NavEKF3_core*)hal.util->malloc_type(sizeof(NavEKF3_core)*num_cores, AP_HAL::Util::MEM_FAST);
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core = (NavEKF3_core*)hal.util->malloc_type(sizeof(NavEKF3_core)*num_cores, AP_HAL::Util::MEM_FAST);
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if (core == nullptr) {
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if (core == nullptr) {
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_enable.set(0);
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_enable.set(0);
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gcs().send_text(MAV_SEVERITY_CRITICAL, "NavEKF3: allocation failed");
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gcs().send_text(MAV_SEVERITY_CRITICAL, "EKF3 allocation failed");
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return false;
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return false;
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}
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}
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@ -756,6 +764,9 @@ bool NavEKF3::InitialiseFilter(void)
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return false;
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return false;
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}
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}
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// set relative error scores for all cores to 0
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resetCoreErrors();
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// Set the primary initially to be the lowest index
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// Set the primary initially to be the lowest index
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primary = 0;
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primary = 0;
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@ -769,6 +780,9 @@ bool NavEKF3::InitialiseFilter(void)
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ret &= core[i].InitialiseFilterBootstrap();
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ret &= core[i].InitialiseFilterBootstrap();
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}
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}
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// set last time the cores were primary to 0
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memset(coreLastTimePrimary_us, 0, sizeof(coreLastTimePrimary_us));
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// zero the structs used capture reset events
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// zero the structs used capture reset events
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memset(&yaw_reset_data, 0, sizeof(yaw_reset_data));
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memset(&yaw_reset_data, 0, sizeof(yaw_reset_data));
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memset((void *)&pos_reset_data, 0, sizeof(pos_reset_data));
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memset((void *)&pos_reset_data, 0, sizeof(pos_reset_data));
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@ -778,7 +792,10 @@ bool NavEKF3::InitialiseFilter(void)
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return ret;
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return ret;
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}
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}
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// Update Filter States - this should be called whenever new IMU data is available
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/*
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Update Filter States - this should be called whenever new IMU data is available
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Execution speed governed by SCHED_LOOP_RATE
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*/
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void NavEKF3::UpdateFilter(void)
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void NavEKF3::UpdateFilter(void)
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{
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{
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if (!core) {
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if (!core) {
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@ -814,37 +831,64 @@ void NavEKF3::UpdateFilter(void)
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}
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}
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runCoreSelection = (imuSampleTime_us - lastUnhealthyTime_us) > 1E7;
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runCoreSelection = (imuSampleTime_us - lastUnhealthyTime_us) > 1E7;
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}
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}
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float primaryErrorScore = core[primary].errorScore();
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if ((primaryErrorScore > 1.0f || !core[primary].healthy()) && runCoreSelection) {
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bool armed = hal.util->get_soft_armed();
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float lowestErrorScore = 0.67f * primaryErrorScore;
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uint8_t newPrimaryIndex = primary; // index for new primary
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// core selection is only available after the vehicle is armed, else forced to lane 0 if its healthy
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if (runCoreSelection && armed) {
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// update this instance's error scores for all active cores and get the primary core's error score
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float primaryErrorScore = updateCoreErrorScores();
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// update the accumulated relative error scores for all active cores
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updateCoreRelativeErrors();
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bool betterCore = false;
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bool altCoreAvailable = false;
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float bestCoreError = 0; // looking for cores that have error lower than the current primary
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uint8_t newPrimaryIndex = primary;
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// loop through all available cores to find if an alternative core is available
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for (uint8_t coreIndex=0; coreIndex<num_cores; coreIndex++) {
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for (uint8_t coreIndex=0; coreIndex<num_cores; coreIndex++) {
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if (coreIndex != primary) {
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if (coreIndex != primary) {
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// an alternative core is available for selection only if healthy and if states have been updated on this time step
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float altCoreError = coreRelativeErrors[coreIndex];
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bool altCoreAvailable = core[coreIndex].healthy() && statePredictEnabled[coreIndex];
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// If the primary core is unhealthy and another core is available, then switch now
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// an alternative core is available for selection based on 2 conditions -
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// If the primary core is still healthy,then switching is optional and will only be done if
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// 1. healthy and states have been updated on this time step
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// a core with a significantly lower error score can be found
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// 2. has relative error less than primary core error
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float altErrorScore = core[coreIndex].errorScore();
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// 3. not been the primary core for at least 10 seconds
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if (altCoreAvailable && (!core[newPrimaryIndex].healthy() || altErrorScore < lowestErrorScore)) {
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altCoreAvailable = core[coreIndex].healthy() &&
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altCoreError < bestCoreError &&
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(imuSampleTime_us - coreLastTimePrimary_us[coreIndex] > 1E7);
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if (altCoreAvailable) {
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// if this core has a significantly lower relative error to the active primary, we consider it as a
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// better core and would like to switch to it even if the current primary is healthy
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betterCore = altCoreError <= -BETTER_THRESH; // a better core if its relative error is below a substantial level than the primary's
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bestCoreError = altCoreError;
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newPrimaryIndex = coreIndex;
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newPrimaryIndex = coreIndex;
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lowestErrorScore = altErrorScore;
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}
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}
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}
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}
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}
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}
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// update the yaw and position reset data to capture changes due to the lane switch
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altCoreAvailable = newPrimaryIndex != primary;
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if (newPrimaryIndex != primary) {
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// Switch cores if another core is available and the active primary core meets one of the following conditions -
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// 1. has a bad error score
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// 2. is unhealthy
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// 3. is healthy, but a better core is available
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// also update the yaw and position reset data to capture changes due to the lane switch
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if (altCoreAvailable && (primaryErrorScore > 1.0f || !core[primary].healthy() || betterCore)) {
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updateLaneSwitchYawResetData(newPrimaryIndex, primary);
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updateLaneSwitchYawResetData(newPrimaryIndex, primary);
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updateLaneSwitchPosResetData(newPrimaryIndex, primary);
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updateLaneSwitchPosResetData(newPrimaryIndex, primary);
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updateLaneSwitchPosDownResetData(newPrimaryIndex, primary);
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updateLaneSwitchPosDownResetData(newPrimaryIndex, primary);
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resetCoreErrors();
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coreLastTimePrimary_us[primary] = imuSampleTime_us;
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primary = newPrimaryIndex;
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primary = newPrimaryIndex;
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lastLaneSwitch_ms = AP_HAL::millis();
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lastLaneSwitch_ms = AP_HAL::millis();
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gcs().send_text(MAV_SEVERITY_CRITICAL, "EKF3 lane switch %u", primary);
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}
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}
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}
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}
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if (primary != 0 && core[0].healthy() && !hal.util->get_soft_armed()) {
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if (primary != 0 && core[0].healthy() && !armed) {
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// when on the ground and disarmed force the first lane. This
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// when on the ground and disarmed force the first lane. This
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// avoids us ending with with a lottery for which IMU is used
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// avoids us ending with with a lottery for which IMU is used
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// in each flight. Otherwise the alignment of the timing of
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// in each flight. Otherwise the alignment of the timing of
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@ -895,7 +939,7 @@ void NavEKF3::checkLaneSwitch(void)
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updateLaneSwitchPosDownResetData(newPrimaryIndex, primary);
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updateLaneSwitchPosDownResetData(newPrimaryIndex, primary);
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primary = newPrimaryIndex;
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primary = newPrimaryIndex;
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lastLaneSwitch_ms = now;
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lastLaneSwitch_ms = now;
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gcs().send_text(MAV_SEVERITY_CRITICAL, "NavEKF3: lane switch %u", primary);
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gcs().send_text(MAV_SEVERITY_CRITICAL, "EKF3 lane switch %u", primary);
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}
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}
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}
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}
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@ -906,6 +950,45 @@ void NavEKF3::requestYawReset(void)
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}
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}
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}
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}
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/*
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Update this instance error score value for all active cores
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*/
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float NavEKF3::updateCoreErrorScores()
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{
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for (uint8_t i = 0; i < num_cores; i++) {
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coreErrorScores[i] = core[i].errorScore();
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}
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return coreErrorScores[primary];
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}
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/*
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Update the relative error for all alternate available cores with respect to primary core's error.
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A positive relative error for a core means it has been more erroneous than the existing primary.
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A negative relative error indicates a core which can be switched to.
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*/
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void NavEKF3::updateCoreRelativeErrors()
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{
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float error = 0;
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for (uint8_t i = 0; i < num_cores; i++) {
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if (i != primary) {
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error = coreErrorScores[i] - coreErrorScores[primary];
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// reduce error for a core only if its better than the primary lane by at least the Relative Error Threshold, this should prevent unnecessary lane changes
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if (error > 0 || error < -MAX(_err_thresh, 0.05)) {
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coreRelativeErrors[i] += error;
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coreRelativeErrors[i] = constrain_float(coreRelativeErrors[i], -CORE_ERR_LIM, CORE_ERR_LIM);
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}
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}
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}
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}
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// Reset the relative error values
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void NavEKF3::resetCoreErrors(void)
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{
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for (uint8_t i = 0; i < num_cores; i++) {
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coreRelativeErrors[i] = 0;
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}
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}
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// Check basic filter health metrics and return a consolidated health status
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// Check basic filter health metrics and return a consolidated health status
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bool NavEKF3::healthy(void) const
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bool NavEKF3::healthy(void) const
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{
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{
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// Check basic filter health metrics and return a consolidated health status
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// Check basic filter health metrics and return a consolidated health status
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bool healthy(void) const;
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bool healthy(void) const;
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// Check that all cores are started and healthy
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// Check that all cores are started and healthy
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bool all_cores_healthy(void) const;
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bool all_cores_healthy(void) const;
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// Update instance error scores for all available cores
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float updateCoreErrorScores(void);
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// Update relative error scores for all alternate available cores
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void updateCoreRelativeErrors(void);
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// Reset error scores for all available cores
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void resetCoreErrors(void);
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// returns the index of the primary core
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// returns the index of the primary core
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// return -1 if no primary core selected
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// return -1 if no primary core selected
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int8_t getPrimaryCoreIndex(void) const;
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int8_t getPrimaryCoreIndex(void) const;
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@ -495,6 +505,7 @@ private:
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AP_Int8 _gsfUseMask; // mask controlling which EKF3 instances will use EKF-GSF yaw estimator data to assit with yaw resets
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AP_Int8 _gsfUseMask; // mask controlling which EKF3 instances will use EKF-GSF yaw estimator data to assit with yaw resets
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AP_Int16 _gsfResetDelay; // number of mSec from loss of navigation to requesting a reset using EKF-GSF yaw estimator data
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AP_Int16 _gsfResetDelay; // number of mSec from loss of navigation to requesting a reset using EKF-GSF yaw estimator data
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AP_Int8 _gsfResetMaxCount; // maximum number of times the EKF3 is allowed to reset it's yaw to the EKF-GSF estimate
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AP_Int8 _gsfResetMaxCount; // maximum number of times the EKF3 is allowed to reset it's yaw to the EKF-GSF estimate
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AP_Float _err_thresh; // lanes have to be consistently better than the primary by at least this threshold to reduce their overall relativeCoreError
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// Possible values for _flowUse
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// Possible values for _flowUse
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#define FLOW_USE_NONE 0
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#define FLOW_USE_NONE 0
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@ -567,9 +578,16 @@ private:
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float core_delta; // the amount of D position change between cores when a change happened
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float core_delta; // the amount of D position change between cores when a change happened
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} pos_down_reset_data;
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} pos_down_reset_data;
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#define MAX_EKF_CORES 3 // maximum allowed EKF Cores to be instantiated
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#define CORE_ERR_LIM 1 // -LIM to LIM relative error range for a core
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#define BETTER_THRESH 0.5 // a lane should have this much relative error difference to be considered for overriding a healthy primary core
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bool runCoreSelection; // true when the primary core has stabilised and the core selection logic can be started
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bool runCoreSelection; // true when the primary core has stabilised and the core selection logic can be started
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bool coreSetupRequired[7]; // true when this core index needs to be setup
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bool coreSetupRequired[MAX_EKF_CORES]; // true when this core index needs to be setup
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uint8_t coreImuIndex[7]; // IMU index used by this core
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uint8_t coreImuIndex[MAX_EKF_CORES]; // IMU index used by this core
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float coreRelativeErrors[MAX_EKF_CORES]; // relative errors of cores with respect to primary
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float coreErrorScores[MAX_EKF_CORES]; // the instance error values used to update relative core error
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uint64_t coreLastTimePrimary_us[MAX_EKF_CORES]; // last time we were using this core as primary
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bool inhibitGpsVertVelUse; // true when GPS vertical velocity use is prohibited
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bool inhibitGpsVertVelUse; // true when GPS vertical velocity use is prohibited
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@ -99,7 +99,9 @@ void NavEKF3::Log_Write_XKF3(uint8_t _core, uint64_t time_us) const
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innovMY : (int16_t)(magInnov.y),
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innovMY : (int16_t)(magInnov.y),
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innovMZ : (int16_t)(magInnov.z),
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innovMZ : (int16_t)(magInnov.z),
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innovYaw : (int16_t)(100*degrees(yawInnov)),
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innovYaw : (int16_t)(100*degrees(yawInnov)),
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innovVT : (int16_t)(100*tasInnov)
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innovVT : (int16_t)(100*tasInnov),
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rerr : coreRelativeErrors[_core],
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errorScore : coreErrorScores[_core]
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};
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};
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AP::logger().WriteBlock(&pkt3, sizeof(pkt3));
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AP::logger().WriteBlock(&pkt3, sizeof(pkt3));
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}
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}
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@ -45,6 +45,20 @@ float NavEKF3_core::errorScore() const
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score = MAX(score, 0.5f * (velTestRatio + posTestRatio));
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score = MAX(score, 0.5f * (velTestRatio + posTestRatio));
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// Check altimeter fusion performance
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// Check altimeter fusion performance
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score = MAX(score, hgtTestRatio);
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score = MAX(score, hgtTestRatio);
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// Check airspeed fusion performance - only when we are using at least 2 airspeed sensors so we can switch lanes with
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// a better one. This only comes into effect for a forward flight vehicle. A sensitivity factor of 0.3 is added to keep the
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// EKF less sensitive to innovations arising due events like strong gusts of wind, thus, prevent reporting high error scores
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if (assume_zero_sideslip()) {
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const auto *arsp = AP::airspeed();
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if (arsp->get_num_sensors() >= 2 && (frontend->_affinity & EKF_AFFINITY_ARSP)) {
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score = MAX(score, 0.3f * tasTestRatio);
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}
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}
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// Check magnetometer fusion performance - need this when magnetometer affinity is enabled to override the inherent compass
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// switching mechanism, and instead be able to move to a better lane
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if (frontend->_affinity & EKF_AFFINITY_MAG) {
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score = MAX(score, 0.3f * (magTestRatio.x + magTestRatio.y + magTestRatio.z));
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}
|
||||||
}
|
}
|
||||||
return score;
|
return score;
|
||||||
}
|
}
|
||||||
|
|
Loading…
Reference in New Issue