predict.h

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#ifndef _PREDICT_H_
#define _PREDICT_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <time.h>
#include <stdbool.h>

#define PREDICT_VERSION_MAJOR 2
#define PREDICT_VERSION_MINOR 0
#define PREDICT_VERSION_PATCH 0
#define PREDICT_VERSION (PREDICT_VERSION_MAJOR * 100 * 100 + PREDICT_VERSION_MINOR * 100 + PREDICT_VERSION_PATCH)
#define PREDICT_VERSION_STRING "2.0.0"
  
int predict_version_major();

int predict_version_minor();

int predict_version_patch();

int predict_version();

char *predict_version_string();

typedef double predict_julian_date_t;

predict_julian_date_t predict_to_julian(time_t time);

time_t predict_from_julian(predict_julian_date_t date);

enum predict_ephemeris {
  EPHEMERIS_SGP4 = 0,
  EPHEMERIS_SDP4 = 1,
  EPHEMERIS_SGP8 = 2,
  EPHEMERIS_SDP8 = 3
};

typedef struct {
    int satellite_number;
    long element_number;
    char designator[10];
    int epoch_year;
    double epoch_day;
    double inclination;
    double right_ascension;
    double eccentricity;
    double argument_of_perigee;
    double mean_anomaly;
    double mean_motion;
    double derivative_mean_motion;
    double second_derivative_mean_motion;
    double bstar_drag_term;
    int revolutions_at_epoch;

    enum predict_ephemeris ephemeris;
    void *ephemeris_data;
} predict_orbital_elements_t;

predict_orbital_elements_t* predict_parse_tle(const char *tle_line_1, const char *tle_line_2);

void predict_destroy_orbital_elements(predict_orbital_elements_t *orbital_elements);

struct predict_position {
    predict_julian_date_t time;

    bool decayed;

    double position[3];
    double velocity[3];

    double latitude;
    double longitude;
    double altitude;
    double footprint;
    int eclipsed;
    double eclipse_depth;
    double phase;
    long revolutions;

    double inclination;
    double right_ascension;
    double argument_of_perigee;
};

int predict_orbit(const predict_orbital_elements_t *orbital_elements, struct predict_position *x, predict_julian_date_t time);

bool predict_is_geosynchronous(const predict_orbital_elements_t *orbital_elements);

double predict_apogee(const predict_orbital_elements_t *x);

double predict_perigee(const predict_orbital_elements_t *x);

bool predict_aos_happens(const predict_orbital_elements_t *x, double latitude);

typedef struct {
    char name[128];
    double latitude;
    double longitude;
    double altitude;
} predict_observer_t;

struct predict_observation {
    predict_julian_date_t time;                       
    double azimuth;
    double azimuth_rate;
    double elevation;
    double elevation_rate;
    double range;                        
    double range_x, range_y, range_z; 
    double range_rate;      
    //  - The satellite is in sunlight
    //  - The satellite is above the horizon
    //  - The sky is dark enough (sun elevation is below a fixed threshold)
    bool visible;
};

predict_observer_t *predict_create_observer(const char *name, double lat, double lon, double alt);

void predict_destroy_observer(predict_observer_t *obs);

void predict_observe_orbit(const predict_observer_t *observer, const struct predict_position *orbit, struct predict_observation *obs);

void predict_observe_moon(const predict_observer_t *observer, predict_julian_date_t time, struct predict_observation *obs);

double predict_moon_ra(predict_julian_date_t time);

double predict_moon_declination(predict_julian_date_t time);

double predict_moon_gha(predict_julian_date_t time);

void predict_observe_sun(const predict_observer_t *observer, predict_julian_date_t time, struct predict_observation *obs);

double predict_sun_ra(predict_julian_date_t time);

double predict_sun_declination(predict_julian_date_t time);

double predict_sun_gha(predict_julian_date_t time);

struct predict_observation predict_next_aos(const predict_observer_t *observer, const predict_orbital_elements_t *orbital_elements, predict_julian_date_t start_time);

struct predict_observation predict_next_los(const predict_observer_t *observer, const predict_orbital_elements_t *orbital_elements, predict_julian_date_t start_time);

struct predict_observation predict_at_max_elevation(const predict_observer_t *observer, const predict_orbital_elements_t *orbital_elements, predict_julian_date_t start_time);

double predict_doppler_shift(const struct predict_observation *observation, double downlink_frequency);

double predict_squint_angle(const predict_observer_t *observer, const struct predict_position *orbit, double alon, double alat);

double predict_refraction(double el);

double predict_refraction_ext(double el, double pressure, double temp);

double predict_refraction_from_apparent(double apparent_el);

double predict_refraction_from_apparent_ext(double apparent_el, double pressure, double temp);

double predict_refraction_rate(double el, double el_rate);

double predict_refraction_rate_ext(double el, double el_rate, double pressure, double temp);

double predict_apparent_elevation(double el);

double predict_apparent_elevation_ext(double el, double pressure, double temp);

double predict_apparent_elevation_rate(double el, double el_rate);

double predict_apparent_elevation_rate_ext(double el, double el_rate, double pressure, double temp);

#ifdef __cplusplus
}
#endif

#endif //_PREDICT_H_