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/************************************************/
/* thetag.c */
/* */
/* obtain the location of Greenwich at epoch */
/* and convert epoch to minutes since 1950 */
/************************************************/
/***** description
*
* $Id: thetag.c,v 1.3 1993/04/27 21:20:45 craig Exp $
*
*/
/***** modification history
*
* translated by f2c (version of 12 March 1993 7:07:21).
*
* $Log: thetag.c,v $
* Revision 1.3 1993/04/27 21:20:45 craig
* fixed the double constant mjd1950 to reflect the current use of
* using the julian day number instead of the mjd number.
*
* Revision 1.2 1993/04/02 18:06:20 craig
* fixed update of ds50 using the mjd epoch
*
* Revision 1.1 1993/04/01 21:06:52 craig
* Initial revision
*
*
*/
/***** include files *****/
#include "satellite.h"
#include "satproto.h"
/***** global variable *****/
extern struct ELEMENT element;
extern struct MCONSTANTS mcnsts;
/**********/
/* thetag */
/**********/
double thetag (double ep)
{
/* System generated locals */
double ret_val;
/* Local variables */
int i;
double temp, theta;
static double mjd1950 = 2433281.5; /* mjd day number for 1950 0 jan */
element.ds50 = ep - mjd1950;
theta = element.ds50 * 6.3003880987 + 1.72944494;
temp = theta / mcnsts.twopi;
i = (int) temp;
temp = (double) i;
ret_val = theta - temp * mcnsts.twopi;
if (ret_val < 0.)
{
ret_val += mcnsts.twopi;
}
return (ret_val);
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.