px4_autopilot/EKF/estimator_interface.h

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/**
 * @file estimator_interface.h
 * Definition of base class for attitude estimators
 *
 * @author Roman Bast <bapstroman@gmail.com>
 *
 */

#include <stdint.h>
#include <matrix/matrix/math.hpp>
#include "RingBuffer.h"
#include "geo.h"
#include "common.h"

using namespace estimator;
class EstimatorInterface
{

public:
	EstimatorInterface();
	~EstimatorInterface();

	virtual bool init(uint64_t timestamp) = 0;
	virtual bool update() = 0;

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

	// gets the innovations of the earth magnetic field measurements
	virtual void get_mag_innov(float mag_innov[3]) = 0;

	// gets the innovations of the heading measurement
	virtual void get_heading_innov(float *heading_innov) = 0;

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

	// gets the innovation variances of the earth magnetic field measurements
	virtual void get_mag_innov_var(float mag_innov_var[3]) = 0;

	// gets the innovation variance of the heading measurement
	virtual void get_heading_innov_var(float *heading_innov_var) = 0;

	virtual void get_state_delayed(float *state) = 0;

	virtual void get_covariances(float *covariances) = 0;

	// get the ekf WGS-84 origin position and height and the system time it was last set
	virtual void get_ekf_origin(uint64_t *origin_time, map_projection_reference_s *origin_pos, float *origin_alt) = 0;

	// get the 1-sigma horizontal and vertical position uncertainty of the ekf WGS-84 position
	virtual void get_ekf_accuracy(float *ekf_eph, float *ekf_epv, bool *dead_reckoning) = 0;

	// ask estimator for sensor data collection decision and do any preprocessing if required, returns true if not defined
	virtual bool collect_gps(uint64_t time_usec, struct gps_message *gps) { return true; }

	virtual bool collect_imu(imuSample &imu) { return true; }

	virtual bool collect_mag(uint64_t time_usec, float *data) { return true; }

	virtual bool collect_baro(uint64_t time_usec, float *data) { return true; }

	virtual bool collect_airspeed(uint64_t time_usec, float *data) { return true; }

	virtual bool collect_range(uint64_t time_usec, float *data) { return true; }

	virtual bool collect_opticalflow(uint64_t time_usec, float *data) { return true; }

	// set delta angle imu data
	void setIMUData(uint64_t time_usec, uint64_t delta_ang_dt, uint64_t delta_vel_dt, float *delta_ang, float *delta_vel);

	// set magnetometer data
	void setMagData(uint64_t time_usec, float *data);
	//void setMagData(uint64_t time_usec, struct magSample *mag);

	// set gps data
	void setGpsData(uint64_t time_usec, struct gps_message *gps);

	// set baro data
	void setBaroData(uint64_t time_usec, float *data);

	// set airspeed data
	void setAirspeedData(uint64_t time_usec, float *data);

	// set range data
	void setRangeData(uint64_t time_usec, float *data);

	// set optical flow data
	void setOpticalFlowData(uint64_t time_usec, float *data);

	// return a address to the parameters struct
	// in order to give access to the application
	parameters *getParamHandle() {return &_params;}

	// set vehicle arm status data
	void set_arm_status(bool data) { _vehicle_armed = data; }

	// set vehicle landed status data
	void set_in_air_status(bool in_air) {_in_air = in_air;}

	bool position_is_valid();


	void copy_quaternion(float *quat)
	{
		for (unsigned i = 0; i < 4; i++) {
			quat[i] = _output_new.quat_nominal(i);
		}
	}
	void copy_velocity(float *vel)
	{
		for (unsigned i = 0; i < 3; i++) {
			vel[i] = _output_new.vel(i);
		}
	}
	void copy_position(float *pos)
	{
		for (unsigned i = 0; i < 3; i++) {
			pos[i] = _output_new.pos(i);
		}
	}
	void copy_timestamp(uint64_t *time_us)
	{
		*time_us = _time_last_imu;
	}

	// Copy the magnetic declination that we wish to save to the EKF2_MAG_DECL parameter for the next startup
	void copy_mag_decl_deg(float *val)
	{
		*val = _mag_declination_to_save_deg;
	}

protected:

	parameters _params;		// filter parameters

	static const uint8_t OBS_BUFFER_LENGTH = 10;	// defines how many measurement samples we can buffer
	static const uint8_t IMU_BUFFER_LENGTH = 30;	// defines how many imu samples we can buffer
	static const unsigned FILTER_UPDATE_PERRIOD_MS = 10;	// ekf prediction period in milliseconds

	float _dt_imu_avg;	// average imu update period in s

	imuSample _imu_sample_delayed;	// captures the imu sample on the delayed time horizon

	// measurement samples capturing measurements on the delayed time horizon
	magSample _mag_sample_delayed;
	baroSample _baro_sample_delayed;
	gpsSample _gps_sample_delayed;
	rangeSample _range_sample_delayed;
	airspeedSample _airspeed_sample_delayed;
	flowSample _flow_sample_delayed;

	outputSample _output_sample_delayed;	// filter output on the delayed time horizon
	outputSample _output_new;	// filter output on the non-delayed time horizon
	imuSample _imu_sample_new;	// imu sample capturing the newest imu data

	uint64_t _imu_ticks;	// counter for imu updates

	bool _imu_updated;      // true if the ekf should update (completed downsampling process)
	bool _initialised;      // true if the ekf interface instance (data buffering) is initialized
	bool _vehicle_armed;    // vehicle arm status used to turn off functionality used on the ground
	bool _in_air;           // we assume vehicle is in the air, set by the given landing detector

	bool _NED_origin_initialised;
	bool _gps_speed_valid;
	float _gps_speed_accuracy;                  // GPS receiver reported speed accuracy (m/s)
	struct map_projection_reference_s _pos_ref; // Contains WGS-84 position latitude and longitude (radians)
	float _gps_hpos_accuracy; // GPS receiver reported 1-sigma horizontal accuracy (m)
	float _gps_origin_eph; // horizontal position uncertainty of the GPS origin
	float _gps_origin_epv; // vertical position uncertainty of the GPS origin

	bool _mag_healthy;              // computed by mag innovation test
	float _yaw_test_ratio;          // yaw innovation consistency check ratio
	float _mag_test_ratio[3];       // magnetometer XYZ innovation consistency check ratios

	float _vel_pos_test_ratio[6];   // velocity and position innovation consistency check ratios

	// data buffer instances
	RingBuffer<imuSample> _imu_buffer;
	RingBuffer<gpsSample> _gps_buffer;
	RingBuffer<magSample> _mag_buffer;
	RingBuffer<baroSample> _baro_buffer;
	RingBuffer<rangeSample> _range_buffer;
	RingBuffer<airspeedSample> _airspeed_buffer;
	RingBuffer<flowSample> 	_flow_buffer;
	RingBuffer<outputSample> _output_buffer;

	uint64_t _time_last_imu;	// timestamp of last imu sample in microseconds
	uint64_t _time_last_gps;	// timestamp of last gps measurement in microseconds
	uint64_t _time_last_mag;	// timestamp of last magnetometer measurement in microseconds
	uint64_t _time_last_baro;	// timestamp of last barometer measurement in microseconds
	uint64_t _time_last_range;	// timestamp of last range measurement in microseconds
	uint64_t _time_last_airspeed;	// timestamp of last airspeed measurement in microseconds

	fault_status_t _fault_status;

	// allocate data buffers and intialise interface variables
	bool initialise_interface(uint64_t timestamp);

	// free buffer memory
	void unallocate_buffers();

	float _mag_declination_gps;         // magnetic declination returned by the geo library using the last valid GPS position (rad)
	float _mag_declination_to_save_deg; // magnetic declination to save to EKF2_MAG_DECL (deg)
};