dsgp4.sgp4init

dsgp4.sgp4init(whichconst, opsmode, satn, epoch, xbstar, xndot, xnddot, xecco, xargpo, xinclo, xmo, xno_kozai, xnodeo, satellite)

This function initializes the sgp4 propagator.

Parameters:

whichconst (tuple): this contains all the necessary constants (tumin, mu, radiusearthkm, xke, j2, j3, j4, j3oj2)), according to the chosen gravitational model (wgs-72, wgs-84, wgs-72old are three possible choices opsmode (str): mode of operation (possibilities: afspc or improved, ‘a’ and ‘i’, respectively satn (str): satellite catalog numbe epoch (torch.float): TLE days since 1949 December 31 00:00 U xbstar (torch.float): drag coefficient (in 1/earth_radii xndot (torch.float): first derivative of mean motion (in revs/day**2 xnddot (torch.float): second derivative mean motion (in revs/day**3 xecco (torch.float): eccentricit xargpo (torch.float): argument of perigee [rad xinclo (torch.float): inclination [rad xmo (torch.float): mean anomaly [rad xno_kozai (torch.float): mean motion (radians/minute xnodeo (torch.float): right ascension of the ascending node [rad satellite (dsgp4.tle.TLE): TLE object

..Note: If satellite._error is different than 0 once this routine is called, then the satellite propagation has had an error. In particular, the following error values hold for satellite._error: * 1 -> eccentricity >=1. or <-0.001 or semi-major axis (in Earth radii) <0.95 * 2 -> mean_motion <0. * 3 -> eccentricity <0. or >1. * 4 -> semi-latus rectum <0. * 5 -> epoch elements are sub-orbital * 6 -> satellite has decayed