px4-firmware/EKF/geo.h

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/**
 * @file geo.h
 *
 * Definition of geo / math functions to perform geodesic calculations
 *
 * @author Thomas Gubler <thomasgubler@student.ethz.ch>
 * @author Julian Oes <joes@student.ethz.ch>
 * @author Lorenz Meier <lm@inf.ethz.ch>
 * @author Anton Babushkin <anton.babushkin@me.com>
 * Additional functions - @author Doug Weibel <douglas.weibel@colorado.edu>
 */
#ifndef GEO_H
#define GEO_H
#ifdef POSIX_SHARED
#include <stdbool.h>
#include "mathlib.h"

#define CONSTANTS_ONE_G					9.80665f		/* m/s^2		*/
#define CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C		1.225f			/* kg/m^3		*/
#define CONSTANTS_AIR_GAS_CONST				287.1f 			/* J/(kg * K)		*/
#define CONSTANTS_ABSOLUTE_NULL_CELSIUS			-273.15f		/* °C			*/
#define CONSTANTS_RADIUS_OF_EARTH			6371000			/* meters (m)		*/
#define M_TWOPI_F 6.28318530717958647692f
#define M_PI_2_F  1.57079632679489661923f
#define M_RAD_TO_DEG 57.29577951308232087679f
#define M_DEG_TO_RAD 0.01745329251994329576f
#define OK 0
#define ERROR -1
// XXX remove
struct crosstrack_error_s {
	bool past_end;		// Flag indicating we are past the end of the line/arc segment
	float distance;		// Distance in meters to closest point on line/arc
	float bearing;		// Bearing in radians to closest point on line/arc
} ;

/* lat/lon are in radians */
struct map_projection_reference_s {
	double lat_rad;
	double lon_rad;
	double sin_lat;
	double cos_lat;
	bool init_done;
	uint64_t timestamp;
};

struct globallocal_converter_reference_s {
	float alt;
	bool init_done;
};

/**
 * Checks if global projection was initialized
 * @return true if map was initialized before, false else
 */
bool map_projection_global_initialized(void);

/**
 * Checks if projection given as argument was initialized
 * @return true if map was initialized before, false else
 */
bool map_projection_initialized(const struct map_projection_reference_s *ref);

/**
 * Get the timestamp of the global map projection
 * @return the timestamp of the map_projection
 */
uint64_t map_projection_global_timestamp(void);

/**
 * Get the timestamp of the map projection given by the argument
 * @return the timestamp of the map_projection
 */
uint64_t map_projection_timestamp(const struct map_projection_reference_s *ref);

/**
 * Writes the reference values of the global projection to ref_lat and ref_lon
 * @return 0 if map_projection_init was called before, -1 else
 */
int map_projection_global_reference(double *ref_lat_rad, double *ref_lon_rad);

/**
 * Writes the reference values of the projection given by the argument to ref_lat and ref_lon
 * @return 0 if map_projection_init was called before, -1 else
 */
int map_projection_reference(const struct map_projection_reference_s *ref, double *ref_lat_rad,
			     double *ref_lon_rad);


/**
 * Initializes the map transformation given by the argument.
 *
 * Initializes the transformation between the geographic coordinate system and
 * the azimuthal equidistant plane
 * @param lat in degrees (47.1234567°, not 471234567°)
 * @param lon in degrees (8.1234567°, not 81234567°)
 */
int map_projection_init_timestamped(struct map_projection_reference_s *ref,
				    double lat_0, double lon_0, uint64_t timestamp);

/**
 * Initializes the map transformation given by the argument and sets the timestamp to now.
 *
 * Initializes the transformation between the geographic coordinate system and
 * the azimuthal equidistant plane
 * @param lat in degrees (47.1234567°, not 471234567°)
 * @param lon in degrees (8.1234567°, not 81234567°)
 */
int map_projection_init(struct map_projection_reference_s *ref, double lat_0, double lon_0);

/**
 * Transforms a point in the geographic coordinate system to the local
 * azimuthal equidistant plane using the global projection
 * @param x north
 * @param y east
 * @param lat in degrees (47.1234567°, not 471234567°)
 * @param lon in degrees (8.1234567°, not 81234567°)
 * @return 0 if map_projection_init was called before, -1 else
 */
int map_projection_global_project(double lat, double lon, float *x, float *y);


/* Transforms a point in the geographic coordinate system to the local
 * azimuthal equidistant plane using the projection given by the argument
* @param x north
* @param y east
* @param lat in degrees (47.1234567°, not 471234567°)
* @param lon in degrees (8.1234567°, not 81234567°)
* @return 0 if map_projection_init was called before, -1 else
*/
int map_projection_project(const struct map_projection_reference_s *ref, double lat, double lon, float *x,
			   float *y);

/**
 * Transforms a point in the local azimuthal equidistant plane to the
 * geographic coordinate system using the global projection
 *
 * @param x north
 * @param y east
 * @param lat in degrees (47.1234567°, not 471234567°)
 * @param lon in degrees (8.1234567°, not 81234567°)
 * @return 0 if map_projection_init was called before, -1 else
 */
int map_projection_global_reproject(float x, float y, double *lat, double *lon);

/**
 * Transforms a point in the local azimuthal equidistant plane to the
 * geographic coordinate system using the projection given by the argument
 *
 * @param x north
 * @param y east
 * @param lat in degrees (47.1234567°, not 471234567°)
 * @param lon in degrees (8.1234567°, not 81234567°)
 * @return 0 if map_projection_init was called before, -1 else
 */
int map_projection_reproject(const struct map_projection_reference_s *ref, float x, float y, double *lat,
			     double *lon);

/**
 * Get reference position of the global map projection
 */
int map_projection_global_getref(double *lat_0, double *lon_0);

/**
 * Initialize the global mapping between global position (spherical) and local position (NED).
 */
int globallocalconverter_init(double lat_0, double lon_0, float alt_0, uint64_t timestamp);

/**
 * Checks if globallocalconverter was initialized
 * @return true if map was initialized before, false else
 */
bool globallocalconverter_initialized(void);

/**
 * Convert from global position coordinates to local position coordinates using the global reference
 */
int globallocalconverter_tolocal(double lat, double lon, float alt, float *x, float *y, float *z);

/**
 * Convert from local position coordinates to global position coordinates using the global reference
 */
int globallocalconverter_toglobal(float x, float y, float z,  double *lat, double *lon, float *alt);

/**
 * Get reference position of the global to local converter
 */
int globallocalconverter_getref(double *lat_0, double *lon_0, float *alt_0);

/**
 * Returns the distance to the next waypoint in meters.
 *
 * @param lat_now current position in degrees (47.1234567°, not 471234567°)
 * @param lon_now current position in degrees (8.1234567°, not 81234567°)
 * @param lat_next next waypoint position in degrees (47.1234567°, not 471234567°)
 * @param lon_next next waypoint position in degrees (8.1234567°, not 81234567°)
 */
float get_distance_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);


/**
 * Creates a new waypoint C on the line of two given waypoints (A, B) at certain distance
 * from waypoint A
 *
 * @param lat_A waypoint A latitude in degrees (47.1234567°, not 471234567°)
 * @param lon_A waypoint A longitude in degrees (8.1234567°, not 81234567°)
 * @param lat_B waypoint B latitude in degrees (47.1234567°, not 471234567°)
 * @param lon_B waypoint B longitude in degrees (8.1234567°, not 81234567°)
 * @param dist distance of target waypoint from waypoint A in meters (can be negative)
 * @param lat_target latitude of target waypoint C in degrees (47.1234567°, not 471234567°)
 * @param lon_target longitude of target waypoint C in degrees (47.1234567°, not 471234567°)
 */
void create_waypoint_from_line_and_dist(double lat_A, double lon_A, double lat_B, double lon_B, float dist,
					double *lat_target, double *lon_target);

/**
 * Creates a waypoint from given waypoint, distance and bearing
 * see http://www.movable-type.co.uk/scripts/latlong.html
 *
 * @param lat_start latitude of starting waypoint in degrees (47.1234567°, not 471234567°)
 * @param lon_start longitude of starting waypoint in degrees (8.1234567°, not 81234567°)
 * @param bearing in rad
 * @param distance in meters
 * @param lat_target latitude of target waypoint in degrees (47.1234567°, not 471234567°)
 * @param lon_target longitude of target waypoint in degrees (47.1234567°, not 471234567°)
 */
void waypoint_from_heading_and_distance(double lat_start, double lon_start, float bearing, float dist,
					double *lat_target, double *lon_target);

/**
 * Returns the bearing to the next waypoint in radians.
 *
 * @param lat_now current position in degrees (47.1234567°, not 471234567°)
 * @param lon_now current position in degrees (8.1234567°, not 81234567°)
 * @param lat_next next waypoint position in degrees (47.1234567°, not 471234567°)
 * @param lon_next next waypoint position in degrees (8.1234567°, not 81234567°)
 */
float get_bearing_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);

void get_vector_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next, float *v_n,
				 float *v_e);

void get_vector_to_next_waypoint_fast(double lat_now, double lon_now, double lat_next, double lon_next,
				      float *v_n, float *v_e);

void add_vector_to_global_position(double lat_now, double lon_now, float v_n, float v_e, double *lat_res,
				   double *lon_res);

int get_distance_to_line(struct crosstrack_error_s *crosstrack_error, double lat_now, double lon_now,
			 double lat_start, double lon_start, double lat_end, double lon_end);

int get_distance_to_arc(struct crosstrack_error_s *crosstrack_error, double lat_now, double lon_now,
			double lat_center, double lon_center,
			float radius, float arc_start_bearing, float arc_sweep);

/*
 * Calculate distance in global frame
 */
float get_distance_to_point_global_wgs84(double lat_now, double lon_now, float alt_now,
		double lat_next, double lon_next, float alt_next,
		float *dist_xy, float *dist_z);

/*
 * Calculate distance in local frame (NED)
 */
float mavlink_wpm_distance_to_point_local(float x_now, float y_now, float z_now,
		float x_next, float y_next, float z_next,
		float *dist_xy, float *dist_z);

float _wrap_180(float bearing);
float _wrap_360(float bearing);
float _wrap_pi(float bearing);
float _wrap_2pi(float bearing);
float get_mag_declination(float lat, float lon);
#else
#include <lib/geo/geo.h>
#endif //POSIX_SHARED
#endif //GEO_H