mymath.h

一个很不错的GPS接收机源程序

#ifndef __NMEA_MATH_H__
#define __NMEA_MATH_H__

#include "info.h"
#define RAND_MAX 100
#define NMEA_PI                     (3.141592653589793)        /**< PI value */
#define NMEA_PI180                  (NMEA_PI / 180)            /**< PI division by 180 */
#define NMEA_EARTHRADIUS_KM         (6378)                 /**< 地球半径km */
#define NMEA_EARTHRADIUS_M          (NMEA_EARTHRADIUS_KM * 1000)    
/**< 地球半径m */
#define NMEA_EARTH_SEMIMAJORAXIS_M  (6378137.0)                     
/**< 地球主轴长度WGS84 */
#define NMEA_EARTH_SEMIMAJORAXIS_KM (NMEA_EARTHMAJORAXIS_KM / 1000) 
/**< 地球主轴长度单位km WGS 84 */
#define NMEA_EARTH_FLATTENING       (1 / 298.257223563)             
/**< 地球平度 WGS 84 */
#define NMEA_DOP_FACTOR             (5)              /**< DOP系数 */

double nmea_degree2radian(double val);
double nmea_radian2degree(double val);

/*
 * NDEG (NMEA degree)
 */

double nmea_ndeg2degree(double val);
double nmea_degree2ndeg(double val);

double nmea_ndeg2radian(double val);
double nmea_radian2ndeg(double val);

/*
 * DOP
 */

double nmea_calc_pdop(double hdop, double vdop);
double nmea_dop2meters(double dop);
double nmea_meters2dop(double meters);

/*
 * positions work
 */

void nmea_info2pos(const nmeaINFO *info, nmeaPOS *pos);
void nmea_pos2info(const nmeaPOS *pos, nmeaINFO *info);

double  nmea_distance(
        const nmeaPOS *from_pos,
        const nmeaPOS *to_pos
        );

double  nmea_distance_ellipsoid(
        const nmeaPOS *from_pos,
        const nmeaPOS *to_pos,
        double *from_azimuth,
        double *to_azimuth
        );

int     nmea_move_horz(
        const nmeaPOS *start_pos,
        nmeaPOS *end_pos,
        double azimuth,
        double distance
        );

int     nmea_move_horz_ellipsoid(
        const nmeaPOS *start_pos,
        nmeaPOS *end_pos,
        double azimuth,
        double distance,
        double *end_azimuth
        );

#endif /* __NMEA_MATH_H__ */