c2tcio¶
- erfa.c2tcio(rc2i, era, rpom)[source]¶
Assemble the celestial to terrestrial matrix from CIO-based components (the celestial-to-intermediate matrix, the Earth Rotation Angle and the polar motion matrix).
- Parameters:
- rc2idouble array
- eradouble array
- rpomdouble array
- Returns:
- rc2tdouble array
Notes
Wraps ERFA function
eraC2tcio
. The ERFA documentation is:- - - - - - - - - - e r a C 2 t c i o - - - - - - - - - - Assemble the celestial to terrestrial matrix from CIO-based components (the celestial-to-intermediate matrix, the Earth Rotation Angle and the polar motion matrix). Given: rc2i double[3][3] celestial-to-intermediate matrix era double Earth rotation angle (radians) rpom double[3][3] polar-motion matrix Returned: rc2t double[3][3] celestial-to-terrestrial matrix Notes: 1) This function constructs the rotation matrix that transforms vectors in the celestial system into vectors in the terrestrial system. It does so starting from precomputed components, namely the matrix which rotates from celestial coordinates to the intermediate frame, the Earth rotation angle and the polar motion matrix. One use of the present function is when generating a series of celestial-to-terrestrial matrices where only the Earth Rotation Angle changes, avoiding the considerable overhead of recomputing the precession-nutation more often than necessary to achieve given accuracy objectives. 2) The relationship between the arguments is as follows: [TRS] = RPOM * R_3(ERA) * rc2i * [CRS] = rc2t * [CRS] where [CRS] is a vector in the Geocentric Celestial Reference System and [TRS] is a vector in the International Terrestrial Reference System (see IERS Conventions 2003). Called: eraCr copy r-matrix eraRz rotate around Z-axis eraRxr product of two r-matrices Reference: McCarthy, D. D., Petit, G. (eds.), 2004, IERS Conventions (2003), IERS Technical Note No. 32, BKG This revision: 2021 May 11 Copyright (C) 2013-2023, NumFOCUS Foundation. Derived, with permission, from the SOFA library. See notes at end of file.