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/**
 * @file ekf.h
 * Class for core functions for ekf attitude and position estimator.
 *
 * @author Roman Bast <bapstroman@gmail.com>
 *
 */

#include "estimator_base.h"

#define sq(_arg)	powf(_arg, 2.0f)

class Ekf : public EstimatorBase
{
public:

	Ekf();
	~Ekf();

	bool update();

	// gets the innovations of velocity and position measurements
	// 0-2 vel, 3-5 pos
	void get_vel_pos_innov(float vel_pos_innov[6]);

	// gets the innovations of the earth magnetic field measurements
	void get_mag_innov(float mag_innov[3]);

	// gets the innovations of the heading measurement
	void get_heading_innov(float *heading_innov);

	// gets the innovation variances of velocity and position measurements
	// 0-2 vel, 3-5 pos
	void get_vel_pos_innov_var(float vel_pos_innov_var[6]);

	// gets the innovation variances of the earth magnetic field measurements
	void get_mag_innov_var(float mag_innov_var[3]);

	// gets the innovation variance of the heading measurement
	void get_heading_innov_var(float *heading_innov_var);

	// get the state vector at the delayed time horizon
	void get_state_delayed(float *state);

	// get the diagonal elements of the covariance matrix
	void get_covariances(float *covariances);

private:

	static const uint8_t _k_num_states = 24;
	static constexpr float _k_earth_rate = 0.000072921f;

	bool _filter_initialised;
	bool _earth_rate_initialised;

	bool _fuse_height;	// baro height data should be fused
	bool _fuse_pos;		// gps position data should be fused
	bool _fuse_hor_vel;		// gps horizontal velocity measurement should be fused
	bool _fuse_vert_vel;	// gps vertical velocity measurement should be fused

	uint64_t _time_last_fake_gps;

	Vector3f _earth_rate_NED;

	matrix::Dcm<float> _R_prev;

	float P[_k_num_states][_k_num_states];	// state covariance matrix

	float _vel_pos_innov[6];	// innovations: 0-2 vel,  3-5 pos
	float _mag_innov[3];		// earth magnetic field innovations
	float _heading_innov;		// heading measurement innovation

	float _vel_pos_innov_var[6]; // innovation variances: 0-2 vel, 3-5 pos
	float _mag_innov_var[3]; // earth magnetic field innovation variance
	float _heading_innov_var; // heading measurement innovation variance

	// complementary filter states
	Vector3f _delta_angle_corr;
	Vector3f _delta_vel_corr;
	Vector3f _vel_corr;

	void calculateOutputStates();

	bool initialiseFilter(void);

	void initialiseCovariance();

	void predictState();

	void predictCovariance();

        void fuseMag();

	void fuseHeading();

	void fuseAirspeed();

	void fuseRange();

	void fuseVelPosHeight();

	void resetVelocity();

	void resetPosition();

	void makeCovSymetrical();

	void limitCov();

	void printCovToFile(char const *filename);

	void assertCovNiceness();

	void makeSymmetrical();

	void constrainStates();

	void fuse(float *K, float innovation);

	void printStates();

	void printStatesFast();

	void calcEarthRateNED(Vector3f &omega, double lat_rad) const;

};