Reference Frames Module¶

Reference frame transformations between inertial and body-fixed coordinate systems for Earth, the Moon, and Mars, synodic (two-body rotating) frames, plus a generic router for any two supported frames.

Transformation Categories¶

ECI ↔ ECEF¶

Generic transformations using common "Earth-Centered Inertial" and "Earth-Centered Earth-Fixed" naming convention. Currently maps to GCRF ↔ ITRF transformations.

GCRF ↔ ITRF¶

Explicit transformations between Geocentric Celestial Reference Frame (inertial) and International Terrestrial Reference Frame (Earth-fixed). Uses IAU 2006/2000A CIO-based theory with classical angles.

EME2000 ↔ GCRF¶

Constant frame bias transformations between Earth Mean Equator and Equinox of J2000.0 (classical inertial) and GCRF (modern inertial).

GCRF ↔ MOD ↔ TOD¶

Equinox-based transformations between GCRF and the mean equator and equinox of date (MOD) and true equator and equinox of date (TOD), and from TOD to ITRF.

GCRF ↔ TEME ↔ ITRF¶

Transformations between GCRF, the true equator and mean equinox of date (TEME) frame in which SGP4 expresses its output, and ITRF.

Lunar Frames¶

Transformations between Lunar-Centered Inertial (LCI) and the Moon-fixed LFPA/LFME frames.

Mars Frames¶

Transformations between Mars-Centered Inertial (MCI) and the Mars-fixed MCMF frame.

Synodic Frames¶

Transformations between GCRF and the synodic EMR, SER, and GSE frames.

Reference Frame Router¶

CelestialFrame and the generic rotation_frame_to_frame/position_frame_to_frame/state_frame_to_frame functions, which convert between any two supported frames, including generic NAIF-ID variants for bodies without a dedicated named frame.

Frame Graph¶

ReferenceFrame and BodyFrame, extending the router to object-scoped orbit-relative and body/sensor frames registered against a specific object.