SGP4Propagator

class ssapy.propagator.SGP4Propagator(t=None, truncate=False)[source][source]

Bases: Propagator

Propagate using simplified perturbation model SGP4.

Parameters:

  • t (float or astropy.time.Time, optional) –

    Reference time at which to compute frame transformation between GCRF and TEME. SGP4 calculations occur in the TEME frame, but useful input and output is in the GCRF frame. In principle, one could do the transformation at every instant in time for which the orbit is queried. However, the rate of change in the transformation is small, ~0.15 arcsec per day, so here we just use a single transformation.

    If float, then should correspond to GPS seconds; i.e., seconds since 1980-01-06 00:00:00 UTC

    If None, then use the time of the orbit being propagated.

  • truncate (bool, optional) – Truncate elements to precision of TLE ASCII format? This may be required in order to reproduce the results of running sgp4 directly from a TLE.