Module transforms 

Coordinate transformation pipeline.

TEME -> GCRS replicates Skyfield’s exact computation path including AU/day unit scaling for bit-exact (0 ULP) parity.

Also provides GCRS -> ITRS, ITRS -> geodetic (WGS84), and topocentric (az/el/range) transformations.

The pure compute functions live here in the core crate; the Rustler decode/encode shims that used to wrap them stay in orbis_nif as glue, so no domain formula lives in the NIF layer. The numerics, summation order, transcendental sequence, and the single sanctioned mul_add site (mat3_vec3_mul_fma) are preserved exactly so the existing Skyfield 0-ULP parity holds.

Structs

GeodeticStationKm

Geodetic ground-station position (WGS84) for topocentric look angles.

PolarMotion

Polar-motion coordinates of the Celestial Intermediate Pole.

TemeStateKm

TEME-frame position and velocity (km, km/s): the input to teme_to_gcrs_compute.

Enums

FrameTransformError

Error returned when public frame-transform inputs are outside the valid domain.

Functions

gcrs_to_itrs_compute

Core GCRS->ITRS transform. Returns (x, y, z) in km.

gcrs_to_itrs_compute_with_polar_motion

Core GCRS->ITRS transform with explicit polar motion.

gcrs_to_itrs_matrix

Build the historical GCRS->ITRS rotation matrix for a given time.

gcrs_to_itrs_matrix_with_polar_motion

Build the GCRS->ITRS rotation matrix with explicit polar motion.

gcrs_to_topocentric_compute

Compute topocentric az/el/range from a ground station to a satellite.

geodetic_from_ecef_proj

Convert ECEF meters to (longitude_degrees, latitude_degrees, altitude_m).

geodetic_to_itrs

Convert geodetic (lat_deg, lon_deg, alt_km) to ECEF/ITRS (km).

greenwich_apparent_sidereal_time_radians

Greenwich Apparent Sidereal Time for an instant, radians in [0, 2pi).

greenwich_mean_sidereal_time_radians

Greenwich Mean Sidereal Time for an instant, radians in [0, 2pi).

itrs_to_gcrs_compute

Core ITRS->GCRS transform. Returns (x, y, z) in km.

itrs_to_gcrs_compute_with_polar_motion

Core ITRS->GCRS transform with explicit polar motion.

itrs_to_gcrs_matrix

Build the ITRS->GCRS rotation matrix for a given time.

itrs_to_gcrs_matrix_with_polar_motion

Build the ITRS->GCRS rotation matrix with explicit polar motion.

itrs_to_geodetic_compute

Convert ECEF/ITRS (km) to geodetic coordinates. Returns (latitude_deg, longitude_deg, altitude_km).

mat3_vec3_mul

Standard (non-FMA) matrix-vector multiply.

mean_of_date_to_itrs_matrix

Rotation from the mean equator and equinox of date to ITRS, i.e. R_z(-GAST) * N (nutation + Earth rotation, without precession or frame bias).

mean_of_date_to_itrs_matrix_with_polar_motion

Mean-of-date to ITRS rotation with explicit polar motion.

polar_motion_matrix

IERS polar-motion matrix, omitting the tiny TIO locator term s'.

teme_to_gcrs_compute

Core TEME->GCRS transform. Returns ((px,py,pz), (vx,vy,vz)).

Type Aliases

Vec3

A bare Cartesian triple (km or km/s depending on context).