SUBROUTINE iau_C2TCIO ( RC2I, ERA, RPOM, RC2T ) *+ * - - - - - - - - - - - * i a u _ 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). * * This routine is part of the International Astronomical Union's * SOFA (Standards of Fundamental Astronomy) software collection. * * Status: support routine. * * Given: * RC2I d(3,3) celestial-to-intermediate matrix * ERA d Earth rotation angle (radians) * RPOM d(3,3) polar-motion matrix * * Returned: * RC2T d(3,3) celestial-to-terrestrial matrix * * Notes: * * 1) This routine 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 routine 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: * iau_CR copy r-matrix * iau_RZ rotate around Z-axis * iau_RXR product of two r-matrices * * Reference: * * McCarthy, D. D., Petit, G. (eds.), 2004, IERS Conventions (2003), * IERS Technical Note No. 32, BKG * * This revision: 2013 August 24 * * SOFA release 2017-04-20 * * Copyright (C) 2017 IAU SOFA Board. See notes at end. * *----------------------------------------------------------------------- IMPLICIT NONE DOUBLE PRECISION RC2I(3,3), ERA, RPOM(3,3), RC2T(3,3) DOUBLE PRECISION R(3,3) * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * Construct the matrix. CALL iau_CR ( RC2I, R ) CALL iau_RZ ( ERA, R ) CALL iau_RXR ( RPOM, R, RC2T ) * Finished. *+---------------------------------------------------------------------- * * Copyright (C) 2017 * Standards Of Fundamental Astronomy Board * of the International Astronomical Union. * * ===================== * SOFA Software License * ===================== * * NOTICE TO USER: * * BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND * CONDITIONS WHICH APPLY TO ITS USE. * * 1. The Software is owned by the IAU SOFA Board ("SOFA"). * * 2. Permission is granted to anyone to use the SOFA software for any * purpose, including commercial applications, free of charge and * without payment of royalties, subject to the conditions and * restrictions listed below. * * 3. You (the user) may copy and distribute SOFA source code to others, * and use and adapt its code and algorithms in your own software, * on a world-wide, royalty-free basis. 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