pint.erfautils.gcrs_posvel_from_itrf

pint.erfautils.gcrs_posvel_from_itrf(loc, toas, obsname='obs')[source]

Return a list of PosVel instances for the observatory at the TOA times.

Observatory location should be given in the loc argument as an astropy EarthLocation object. This location will be in the ITRF frame (i.e. co-rotating with the Earth).

The optional obsname argument will be used as label in the returned PosVel instance.

This routine returns a list of PosVel instances, containing the positions (m) and velocities (m / s) at the times of the toas and referenced to the Earth-centered Inertial (ECI, aka GCRS) coordinates. This routine is basically SOFA’s pvtob() [Position and velocity of a terrestrial observing station] with an extra rotation from c2ixys() [Form the celestial to intermediate-frame-of-date matrix given the CIP X,Y and the CIO locator s].

This version uses astropy’s internal routines, which use IERS A data rather than the final IERS B values. These do differ, and yield results that are different by ~20 m.