Function lupnt::ItrfToGcrf(Real, const Vec6&)

• Defined in File frame_conversions.cc

Function Documentation

Vec6 lupnt::ItrfToGcrf(Real t_tdb, const Vec6 &rv_itrf)

Converts a state vector from ITRF to GCRF (ECEF to ECI) at epoch t_tdb.

See the note on GcrfToItrf regarding InitFrameConversionFromSpice.

Used throughout the simulator wherever Earth-fixed states (ground-station positions, ECEF-frame measurements, ITRF-referenced SPICE/EOP data) must be expressed in the inertial frame — e.g. by ConvertFrame when propagating dynamics or computing line-of-sight vectors in GCRF.

Note

Astrodynamics Convention & Modeling Reference, Version 1.1, Page 37

Parameters:

• t_tdb – Epoch [s, TDB since J2000]

• rv_itrf – Position+velocity in ITRF (ECEF) [m, m/s]

Returns:

Position+velocity in GCRF (ECI) [m, m/s]