ekf2Check.cpp

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#include "../PreFlightCheck.hpp"

#include <HealthFlags.h>
#include <math.h>
#include <lib/parameters/param.h>
#include <systemlib/mavlink_log.h>
#include <uORB/Subscription.hpp>
#include <uORB/topics/estimator_status.h>
#include <uORB/topics/subsystem_info.h>

bool PreFlightCheck::ekf2Check(orb_advert_t *mavlink_log_pub, vehicle_status_s &vehicle_status, const bool optional,
                   const bool report_fail, const bool enforce_gps_required)
{
    bool success = true; // start with a pass and change to a fail if any test fails
    bool present = true;
    float test_limit = 1.0f; // pass limit re-used for each test

    bool gps_success = true;
    bool gps_present = true;

    // Get estimator status data if available and exit with a fail recorded if not
    uORB::SubscriptionData<estimator_status_s> status_sub{ORB_ID(estimator_status)};
    status_sub.update();
    const estimator_status_s &status = status_sub.get();

    if (status.timestamp == 0) {
        present = false;
        goto out;
    }

    // Check if preflight check performed by estimator has failed
    if (status.pre_flt_fail_innov_heading ||
        status.pre_flt_fail_innov_vel_horiz ||
        status.pre_flt_fail_innov_vel_vert ||
        status.pre_flt_fail_innov_height ||
        status.pre_flt_fail_mag_field_disturbed) {
        if (report_fail) {
            if (status.pre_flt_fail_innov_heading) {
                mavlink_log_critical(mavlink_log_pub, "Preflight Fail: heading estimate not stable");

            } else if (status.pre_flt_fail_innov_vel_horiz) {
                mavlink_log_critical(mavlink_log_pub, "Preflight Fail: horizontal velocity estimate not stable");

            } else if (status.pre_flt_fail_innov_vel_horiz) {
                mavlink_log_critical(mavlink_log_pub, "Preflight Fail: vertical velocity estimate not stable");

            } else if (status.pre_flt_fail_innov_height) {
                mavlink_log_critical(mavlink_log_pub, "Preflight Fail: height estimate not stable");

            } else if (status.pre_flt_fail_mag_field_disturbed) {
                mavlink_log_critical(mavlink_log_pub, "Preflight Fail: strong magnetic interference detected");
            }
        }

        success = false;
        goto out;
    }

    // check vertical position innovation test ratio
    param_get(param_find("COM_ARM_EKF_HGT"), &test_limit);

    if (status.hgt_test_ratio > test_limit) {
        if (report_fail) {
            mavlink_log_critical(mavlink_log_pub, "Preflight Fail: Height estimate error");
        }

        success = false;
        goto out;
    }

    // check velocity innovation test ratio
    param_get(param_find("COM_ARM_EKF_VEL"), &test_limit);

    if (status.vel_test_ratio > test_limit) {
        if (report_fail) {
            mavlink_log_critical(mavlink_log_pub, "Preflight Fail: Velocity estimate error");
        }

        success = false;
        goto out;
    }

    // check horizontal position innovation test ratio
    param_get(param_find("COM_ARM_EKF_POS"), &test_limit);

    if (status.pos_test_ratio > test_limit) {
        if (report_fail) {
            mavlink_log_critical(mavlink_log_pub, "Preflight Fail: Position estimate error");
        }

        success = false;
        goto out;
    }

    // check magnetometer innovation test ratio
    param_get(param_find("COM_ARM_EKF_YAW"), &test_limit);

    if (status.mag_test_ratio > test_limit) {
        if (report_fail) {
            mavlink_log_critical(mavlink_log_pub, "Preflight Fail: Yaw estimate error");
        }

        success = false;
        goto out;
    }

    // check accelerometer delta velocity bias estimates
    param_get(param_find("COM_ARM_EKF_AB"), &test_limit);

    for (uint8_t index = 13; index < 16; index++) {
        // allow for higher uncertainty in estimates for axes that are less observable to prevent false positives
        // adjust test threshold by 3-sigma
        float test_uncertainty = 3.0f * sqrtf(fmaxf(status.covariances[index], 0.0f));

        if (fabsf(status.states[index]) > test_limit + test_uncertainty) {
            if (report_fail) {
                mavlink_log_critical(mavlink_log_pub, "Preflight Fail: High Accelerometer Bias");
            }

            success = false;
            goto out;
        }
    }

    // check gyro delta angle bias estimates
    param_get(param_find("COM_ARM_EKF_GB"), &test_limit);

    if (fabsf(status.states[10]) > test_limit || fabsf(status.states[11]) > test_limit
        || fabsf(status.states[12]) > test_limit) {
        if (report_fail) {
            mavlink_log_critical(mavlink_log_pub, "Preflight Fail: High Gyro Bias");
        }

        success = false;
        goto out;
    }

    // If GPS aiding is required, declare fault condition if the required GPS quality checks are failing
    if (enforce_gps_required || report_fail) {
        const bool ekf_gps_fusion = status.control_mode_flags & (1 << estimator_status_s::CS_GPS);
        const bool ekf_gps_check_fail = status.gps_check_fail_flags > 0;

        gps_success = ekf_gps_fusion; // default to success if gps data is fused

        if (ekf_gps_check_fail) {
            if (report_fail) {
                // Only report the first failure to avoid spamming
                const char *message = nullptr;

                if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_GPS_FIX)) {
                    message = "Preflight%s: GPS fix too low";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MIN_SAT_COUNT)) {
                    message = "Preflight%s: not enough GPS Satellites";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MIN_PDOP)) {
                    message = "Preflight%s: GPS PDOP too low";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MAX_HORZ_ERR)) {
                    message = "Preflight%s: GPS Horizontal Pos Error too high";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MAX_VERT_ERR)) {
                    message = "Preflight%s: GPS Vertical Pos Error too high";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MAX_SPD_ERR)) {
                    message = "Preflight%s: GPS Speed Accuracy too low";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MAX_HORZ_DRIFT)) {
                    message = "Preflight%s: GPS Horizontal Pos Drift too high";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MAX_VERT_DRIFT)) {
                    message = "Preflight%s: GPS Vertical Pos Drift too high";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MAX_HORZ_SPD_ERR)) {
                    message = "Preflight%s: GPS Hor Speed Drift too high";

                } else if (status.gps_check_fail_flags & (1 << estimator_status_s::GPS_CHECK_FAIL_MAX_VERT_SPD_ERR)) {
                    message = "Preflight%s: GPS Vert Speed Drift too high";

                } else {
                    if (!ekf_gps_fusion) {
                        // Likely cause unknown
                        message = "Preflight%s: Estimator not using GPS";
                        gps_present = false;

                    } else {
                        // if we land here there was a new flag added and the code not updated. Show a generic message.
                        message = "Preflight%s: Poor GPS Quality";
                    }
                }

                if (message) {
                    if (enforce_gps_required) {
                        mavlink_log_critical(mavlink_log_pub, message, " Fail");

                    } else {
                        mavlink_log_warning(mavlink_log_pub, message, "");
                    }
                }
            }

            gps_success = false;

            if (enforce_gps_required) {
                success = false;
                goto out;
            }
        }
    }

out:
    set_health_flags(subsystem_info_s::SUBSYSTEM_TYPE_AHRS, present, !optional, success && present, vehicle_status);
    set_health_flags(subsystem_info_s::SUBSYSTEM_TYPE_GPS, gps_present, enforce_gps_required, gps_success, vehicle_status);

    return success;
}