px4_autopilot/test/test_EKF_gps_yaw.cpp

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/**
 * Test the gps yaw fusion
 * @author Kamil Ritz <ka.ritz@hotmail.com>
 */

#include <gtest/gtest.h>
#include "EKF/ekf.h"
#include "sensor_simulator/sensor_simulator.h"
#include "sensor_simulator/ekf_wrapper.h"
#include "test_helper/reset_logging_checker.h"

class EkfGpsHeadingTest : public ::testing::Test {
 public:

	EkfGpsHeadingTest(): ::testing::Test(),
	_ekf{std::make_shared<Ekf>()},
	_sensor_simulator(_ekf),
	_ekf_wrapper(_ekf) {};

	std::shared_ptr<Ekf> _ekf;
	SensorSimulator _sensor_simulator;
	EkfWrapper _ekf_wrapper;

	// Setup the Ekf with synthetic measurements
	void SetUp() override
	{
		_ekf->init(0);
		_sensor_simulator._gps.setYaw(NAN);
		_sensor_simulator.runSeconds(2);
		_ekf_wrapper.enableGpsFusion();
		_ekf_wrapper.enableGpsHeadingFusion();
		_sensor_simulator.startGps();
		_sensor_simulator.runSeconds(11);
	}
};

TEST_F(EkfGpsHeadingTest, fusionStartWithReset)
{
	// GIVEN:EKF that fuses GPS

	// WHEN: enabling GPS heading fusion and heading difference is bigger than 15 degrees
	const float gps_heading = _ekf_wrapper.getYawAngle() + math::radians(20.f);
	_sensor_simulator._gps.setYaw(gps_heading);
	_ekf_wrapper.enableGpsHeadingFusion();
	const int initial_quat_reset_counter = _ekf_wrapper.getQuaternionResetCounter();
	_sensor_simulator.runSeconds(0.2);

	// THEN: GPS heading fusion should have started;
	EXPECT_TRUE(_ekf_wrapper.isIntendingGpsHeadingFusion());

	// AND: a reset to GPS heading is performed
	EXPECT_EQ(_ekf_wrapper.getQuaternionResetCounter(), initial_quat_reset_counter + 1);
	EXPECT_NEAR(_ekf_wrapper.getYawAngle(), gps_heading, 0.001);

	// WHEN: GPS heading is disabled
	_sensor_simulator._gps.stop();
	_sensor_simulator.runSeconds(11);

	// THEN: after a while the fusion should be stopped
	EXPECT_FALSE(_ekf_wrapper.isIntendingGpsHeadingFusion());
}

TEST_F(EkfGpsHeadingTest, yawConvergence)
{
	// GIVEN: an initial GPS yaw, not aligned with the current one
	float gps_heading = _ekf_wrapper.getYawAngle() + math::radians(10.f);
	_sensor_simulator._gps.setYaw(gps_heading);

	// WHEN: the GPS yaw fusion is activated
	_ekf_wrapper.enableGpsHeadingFusion();
	_sensor_simulator.runSeconds(5);

	// THEN: the estimate is reset and stays close to the measurement
	float yaw_est = _ekf_wrapper.getYawAngle();
	EXPECT_NEAR(yaw_est, gps_heading, math::radians(0.05f))
		<< "yaw est: " << math::degrees(yaw_est) << "gps yaw: " << math::degrees(gps_heading);

	// AND WHEN: the the measurement changes
	gps_heading += math::radians(2.f);
	_sensor_simulator._gps.setYaw(gps_heading);
	_sensor_simulator.runSeconds(6);

	// THEN: the estimate slowly converges to the new measurement
	// Note that the process is slow, because the gyro did not detect any motion
	yaw_est = _ekf_wrapper.getYawAngle();
	EXPECT_NEAR(yaw_est, gps_heading, math::radians(0.5f))
		<< "yaw est: " << math::degrees(yaw_est) << "gps yaw: " << math::degrees(gps_heading);
}

TEST_F(EkfGpsHeadingTest, fallBackToMag)
{
	// GIVEN: an initial GPS yaw, not aligned with the current one
	// GPS yaw is expected to arrive a bit later, first feed some NANs
	// to the filter
	_sensor_simulator.runSeconds(6);
	float gps_heading = _ekf_wrapper.getYawAngle() + math::radians(10.f);
	_sensor_simulator._gps.setYaw(gps_heading);

	// WHEN: the GPS yaw fusion is activated
	_sensor_simulator.runSeconds(1);

	// THEN: GPS heading fusion should have started, and mag
	// fusion should be disabled
	EXPECT_TRUE(_ekf_wrapper.isIntendingGpsHeadingFusion());
	EXPECT_FALSE(_ekf_wrapper.isIntendingMagHeadingFusion());
	EXPECT_FALSE(_ekf_wrapper.isIntendingMag3DFusion());

	// BUT WHEN: the GPS yaw is suddenly invalid
	gps_heading = NAN;
	_sensor_simulator._gps.setYaw(gps_heading);
	_sensor_simulator.runSeconds(6);

	// THEN: after a few seconds, the fusion should stop and
	// the estimator should fall back to mag fusion
	EXPECT_FALSE(_ekf_wrapper.isIntendingGpsHeadingFusion());
	EXPECT_TRUE(_ekf_wrapper.isIntendingMagHeadingFusion());
}