Frame Transforms

The satkit.frametransform module includes functions to rotate between multiple inertial and Earth-fixed coordinate frames.

Frame transforms are generally output as Quaternions. See related documentation here

Coordinate frames

The satkit.frametransform module supports transforms between the following frames:

• GCRF - Geocentric Celestial Reference Frame.

• ITRF - International Terrestrial Reference Frame

• TEME - True Equator, Mean Equinox Frame

• MOD - Mean of Date Frame

• TIRS - Terrestrial Intermediate Reference System

• CIRS - Celestial Intermediate Reference System

Calculation Notes:

Transformation between the GCRF and the ITRF is performed via the detailed calculations described by the International Earth Rotation and Reference System Service in their Technical Note 36: https://www.iers.org/IERS/EN/Publications/TechnicalNotes/tn36.html. This is a computationally expensive calculation.