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/* H+
* Title : sgp4.h
* Author : Bryce A. Roberts
* Date : 23 February 1999
* Synopsis : header file for SGP4 propagation routines
* SCCS : @(#)sgp4.h 1.1 03/04/03
* Revisions :
* mm/dd/yy name description
* H-
*/
#ifndef _SGP4_H
#define _SGP4_H
#include <math.h>
#include <stdlib.h>
#include <time.h>
#include <strings.h>
#define MJD2000 (51544.0)
/* the data structure itself */
struct sgp4_st {
/* NORAD tle components */
double epochTime, n0, n0dt, n0dt2, bstar, i0, raan, e0, w0, M0;
/* derived variables */
double n0dp, a0dp, q0ms4, theta, theta_2, zeta_4, beta0_2, eta, C1,
C1_2, C1_3, C1_4, C3, C4, C5, D2, D3, D4, mdot, wdot, raandot;
};
typedef struct sgp4_st * SGP4;
/* create a new instance of SGP4 */
extern SGP4 SGP4_create(void);
/* destroy an instance of SGP4 */
extern void SGP4_destroy(SGP4 sgp4);
/* convert NORAD time string to TJD */
extern int SGP4_getTime(const char *str, double *t);
/* do time-invariant initializations */
extern void SGP4_init(SGP4 sgp4);
/* get a state vector at a point in time */
extern void SGP4_getStateVector(SGP4 sgp4, double t, double pos[3],
double vel[3]);
/* finds the pole (orbit plane normal) */
extern void SGP4_getPole(double pos[3], double vel[3], double pole[3]);
/* sets the elements of an instance of SGP4 */
extern void SGP4_set(SGP4 sgp4, double epochTime, double n0dt, double n0dt2,
double bstar, double i0, double raan, double e0,
double w0, double M0, double n0);
/* precesses a direction vector from t1 to t2 */
void SGP4_precess(double v[3], double t1, double t2);
#endif
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