c_getorb - Calculate the orbit number, equatorial crossing, and the direction of the pass

SYNTAX

FUNCTION c_getorb (tsec, model, orbit, passdir, eqxing)

    double  *tsec;
    struct MODEL *model;
    long *orbit;
    long *passdir;
    double  *eqxing;

PARAMETERS

tsec (double *, input)

Total seconds past midnight Greenwich mean time. If the julian day of acquisition is different from the day of the ephemeris data, tsec should be the seconds from 00:00:00 of the day of acquisition.

model (struct MODEL *, input)

Structure containing the model and orbital information.

orbit (long *, output)

Calculated orbit number.

passdir (long *, output)

Pass direction:

     =  1:	Ascending pass
     = -1:	Descending pass

eqxing (double *, output)

Equatorial crossing in radians.

DESCRIPTION

Propagate the satellite orbit to the time specified by tsec. Calculate the direction of the pass and the orbit number referenced from the equator. Calculate the longitude at which the satellite orbit crosses the equator.

RETURN VALUE

c_getorb() has no return value.