test_EKF_basics.cpp

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#include <gtest/gtest.h>
#include <math.h>
#include "EKF/ekf.h"

class EkfInitializationTest : public ::testing::Test {
 public:

    Ekf _ekf{};

    // Basics sensors
    const uint32_t _imu_dt_us{4000};    // 250 Hz   Period between IMU updates
    const uint32_t _baro_dt_us{12500};  // 80 Hz    Period between barometer updates
    const uint32_t _mag_dt_us{12500};   // 80 Hz    Period between magnetometer updates
    const uint32_t _gps_dt_us{200000};  // 5 Hz     Period between GPS updates

    // Flags that control if a sensor is fused
    bool _fuse_imu{true};
    bool _fuse_baro{true};
    bool _fuse_mag{true};
    bool _fuse_gps{false};  // GPS measurements are expected to not come in from beginning

    // GPS message
    gps_message _gps_message{};

    uint32_t _update_dt_us{};           // greatest common divider of all basic sensor periods
    const uint32_t _init_duration_us{2000000};  // 2s   Duration of

    // counter of how many sensor measurement are put into Ekf
    uint32_t _counter_imu{0};
    uint32_t _counter_baro{0};
    uint32_t _counter_mag{0};

    uint32_t _t_us{0};

    // Setup the Ekf with synthetic measurements
    void SetUp() override
    {

        _ekf.init(0);

        // setup gps message to reasonable default values
        _gps_message.time_usec = 0;
        _gps_message.lat = 473566094;
        _gps_message.lon = 85190237;
        _gps_message.alt = 422056;
        _gps_message.yaw = 0.0f;
        _gps_message.yaw_offset = 0.0f;
        _gps_message.fix_type = 3;
        _gps_message.eph = 0.5f;
        _gps_message.epv = 0.8f;
        _gps_message.sacc = 0.2f;
        _gps_message.vel_m_s = 0.0;
        _gps_message.vel_ned[0] = 0.0f;
        _gps_message.vel_ned[1] = 0.0f;
        _gps_message.vel_ned[2] = 0.0f;
        _gps_message.vel_ned_valid = 1;
        _gps_message.nsats = 16;
        _gps_message.pdop = 0.0f;

        update_with_const_sensors(_init_duration_us);

        // output how many sensor measurement were put into the EKF
        // std::cout << "Initialized EKF with:" << std::endl;
        // std::cout << "update_dt_us: " << _update_dt_us << std::endl;
        // std::cout << "counter_imu:  " << _counter_imu << std::endl
        //    << "counter_baro: " << _counter_baro << std::endl
        //    << "counter_mag:  " << _counter_mag << std::endl;
    }

    void update_with_const_sensors(uint32_t duration_us,
            Vector3f ang_vel = Vector3f{0.0f,0.0f,0.0f},
            Vector3f accel = Vector3f{0.0f,0.0f,-CONSTANTS_ONE_G},
            Vector3f mag_data = Vector3f{0.2f, 0.0f, 0.4f},
            float baro_data = 122.2f)
    {
        // store start time
        uint32_t start_time_us = _t_us;

        // compute update time step such that we can update the basic sensor at different rates
        _update_dt_us = std::__gcd(_imu_dt_us,std::__gcd(_mag_dt_us,std::__gcd(_baro_dt_us,_gps_dt_us)));

        // update EKF with synthetic sensor measurements
        for( ; _t_us < start_time_us+duration_us; _t_us += _update_dt_us)
        {
            // Check which sensors update we should do
            if(_fuse_imu && !(_t_us %_imu_dt_us))
            {
                // push imu data into estimator
                imuSample imu_sample_new;
                imu_sample_new.time_us = _t_us;
                imu_sample_new.delta_ang_dt = _imu_dt_us * 1.e-6f;
                imu_sample_new.delta_ang = ang_vel * imu_sample_new.delta_ang_dt;
                imu_sample_new.delta_vel_dt = _imu_dt_us * 1.e-6f;
                imu_sample_new.delta_vel = accel * imu_sample_new.delta_vel_dt;

                _ekf.setIMUData(imu_sample_new);
                _counter_imu++;
            }
            if(_fuse_baro && !(_t_us % _baro_dt_us))
            {
                _ekf.setBaroData(_t_us,baro_data);
                _counter_baro++;
            }
            if(_fuse_mag && !(_t_us % _mag_dt_us))
            {
                float mag[3];
                mag_data.copyTo(mag);
                _ekf.setMagData(_t_us,mag);
                _counter_mag++;
            }
            if(_fuse_gps && !(_t_us % _gps_dt_us))
            {
                _gps_message.time_usec = _t_us;
                _ekf.setGpsData(_t_us,_gps_message);
                _counter_mag++;
            }

            _ekf.update();
        }
    }

    // Use this method to clean up any memory, network etc. after each test
    void TearDown() override
    {

    }
};


TEST_F(EkfInitializationTest, tiltAlign)
{
    // GIVEN: reasonable static sensor data for some duration
    // THEN: EKF should tilt align
    EXPECT_EQ(true,_ekf.attitude_valid());
}

TEST_F(EkfInitializationTest, initialControlMode)
{
    // GIVEN: reasonable static sensor data for some duration
    // THEN: EKF control status should be reasonable
    filter_control_status_u control_status;
    _ekf.get_control_mode(&control_status.value);

    EXPECT_EQ(1, (int) control_status.flags.tilt_align);
    EXPECT_EQ(1, (int) control_status.flags.yaw_align);
    EXPECT_EQ(0, (int) control_status.flags.gps);
    EXPECT_EQ(0, (int) control_status.flags.opt_flow);
    EXPECT_EQ(1, (int) control_status.flags.mag_hdg);
    EXPECT_EQ(0, (int) control_status.flags.mag_3D);
    EXPECT_EQ(0, (int) control_status.flags.mag_dec);
    EXPECT_EQ(0, (int) control_status.flags.in_air);
    EXPECT_EQ(0, (int) control_status.flags.wind);
    EXPECT_EQ(1, (int) control_status.flags.baro_hgt);
    EXPECT_EQ(0, (int) control_status.flags.rng_hgt);
    EXPECT_EQ(0, (int) control_status.flags.gps_hgt);
    EXPECT_EQ(0, (int) control_status.flags.ev_pos);
    EXPECT_EQ(0, (int) control_status.flags.ev_yaw);
    EXPECT_EQ(0, (int) control_status.flags.ev_hgt);
    EXPECT_EQ(0, (int) control_status.flags.fuse_beta);
    EXPECT_EQ(0, (int) control_status.flags.mag_field_disturbed);
    EXPECT_EQ(0, (int) control_status.flags.fixed_wing);
    EXPECT_EQ(0, (int) control_status.flags.mag_fault);
    EXPECT_EQ(0, (int) control_status.flags.gnd_effect);
    EXPECT_EQ(0, (int) control_status.flags.rng_stuck);
    EXPECT_EQ(0, (int) control_status.flags.gps_yaw);
    EXPECT_EQ(0, (int) control_status.flags.mag_aligned_in_flight);
    EXPECT_EQ(0, (int) control_status.flags.ev_vel);
    EXPECT_EQ(0, (int) control_status.flags.synthetic_mag_z);
}

TEST_F(EkfInitializationTest, convergesToZero)
{
    // GIVEN: initialized EKF with default IMU, baro and mag input for 2s
    // WHEN: Added more defautl sensor measurements
    update_with_const_sensors(4000000); // for further 4s

    float converged_pos[3];
    float converged_vel[3];
    float converged_accel_bias[3];
    float converged_gyro_bias[3];
    _ekf.get_position(converged_pos);
    _ekf.get_velocity(converged_vel);
    _ekf.get_accel_bias(converged_accel_bias);
    _ekf.get_gyro_bias(converged_gyro_bias);

    // THEN: EKF should stay or converge to zero
    for(int i=0; i<3; ++i)
    {
        EXPECT_NEAR(0.0f,converged_pos[i],0.001f);
        EXPECT_NEAR(0.0f,converged_vel[i],0.001f);
        EXPECT_NEAR(0.0f,converged_accel_bias[i],0.001f);
        EXPECT_NEAR(0.0f,converged_gyro_bias[i],0.001f);
    }
}

TEST_F(EkfInitializationTest, gpsFusion)
{
    // GIVEN: initialized EKF with default IMU, baro and mag input for 2s
    // WHEN: setting GPS measurements for 11s, minimum GPS health time is set to 10 sec

    _fuse_gps = true;
    update_with_const_sensors(11000000,Vector3f{0.0f,0.0f,0.0f},Vector3f{0.0f,0.0f,-CONSTANTS_ONE_G}); // for further 3s

    // THEN: EKF should fuse GPS, but no other position sensor
    filter_control_status_u control_status;
    _ekf.get_control_mode(&control_status.value);
    EXPECT_EQ(1, (int) control_status.flags.tilt_align);
    EXPECT_EQ(1, (int) control_status.flags.yaw_align);
    EXPECT_EQ(1, (int) control_status.flags.gps);
    EXPECT_EQ(0, (int) control_status.flags.opt_flow);
    EXPECT_EQ(1, (int) control_status.flags.mag_hdg);
    EXPECT_EQ(0, (int) control_status.flags.mag_3D);
    EXPECT_EQ(0, (int) control_status.flags.mag_dec);
    EXPECT_EQ(0, (int) control_status.flags.in_air);
    EXPECT_EQ(0, (int) control_status.flags.wind);
    EXPECT_EQ(1, (int) control_status.flags.baro_hgt);
    EXPECT_EQ(0, (int) control_status.flags.rng_hgt);
    EXPECT_EQ(0, (int) control_status.flags.gps_hgt);
    EXPECT_EQ(0, (int) control_status.flags.ev_pos);
    EXPECT_EQ(0, (int) control_status.flags.ev_yaw);
    EXPECT_EQ(0, (int) control_status.flags.ev_hgt);
    EXPECT_EQ(0, (int) control_status.flags.fuse_beta);
    EXPECT_EQ(0, (int) control_status.flags.mag_field_disturbed);
    EXPECT_EQ(0, (int) control_status.flags.fixed_wing);
    EXPECT_EQ(0, (int) control_status.flags.mag_fault);
    EXPECT_EQ(0, (int) control_status.flags.gnd_effect);
    EXPECT_EQ(0, (int) control_status.flags.rng_stuck);
    EXPECT_EQ(0, (int) control_status.flags.gps_yaw);
    EXPECT_EQ(0, (int) control_status.flags.mag_aligned_in_flight);
    EXPECT_EQ(0, (int) control_status.flags.ev_vel);
    EXPECT_EQ(0, (int) control_status.flags.synthetic_mag_z);
}

TEST_F(EkfInitializationTest, accleBiasEstimation)
{
    // GIVEN: initialized EKF with default IMU, baro and mag input for 2s
    // WHEN: Added more sensor measurements with accel bias and gps measurements
    Vector3f accel_bias = {0.0f,0.0f,0.1f};

    _fuse_gps = true;
    update_with_const_sensors(10000000,Vector3f{0.0f,0.0f,0.0f},Vector3f{0.0f,0.0f,-CONSTANTS_ONE_G}+accel_bias); // for further 10s

    float converged_pos[3];
    float converged_vel[3];
    float converged_accel_bias[3];
    float converged_gyro_bias[3];
    _ekf.get_position(converged_pos);
    _ekf.get_velocity(converged_vel);
    _ekf.get_accel_bias(converged_accel_bias);
    _ekf.get_gyro_bias(converged_gyro_bias);

    // THEN: EKF should estimate bias correctelly
    for(int i=0; i<3; ++i)
    {
        EXPECT_NEAR(0.0f,converged_pos[i],0.001f) << "i: " << i;
        EXPECT_NEAR(0.0f,converged_vel[i],0.001f) << "i: " << i;
        EXPECT_NEAR(accel_bias(i),converged_accel_bias[i],0.001f) << "i: " << i;
        EXPECT_NEAR(0.0f,converged_gyro_bias[i],0.001f) << "i: " << i;
    }
}

// TODO: Add sampling tests