SUBROUTINE FUNDARG ( T, L, LP, F, D, OM ) *+ * - - - - - - - - - - - * F U N D A R G * - - - - - - - - - - - * * This routine is part of the International Earth Rotation and * Reference Systems Service (IERS) Conventions software collection. * * This subroutine computes the lunisolar fundamental arguments. * The model used is from Simon et al. (1994) as recommended by the IERS * Conventions (2010). Refer to IERS Conventions (2010) Chapter 5 * Sections 5.7.1 - 5.7.2 (pp. 57 - 59). * * In general, Class 1, 2, and 3 models represent physical effects that * act on geodetic parameters while canonical models provide lower-level * representations or basic computations that are used by Class 1, 2, or * 3 models. * * Status: Canonical model * * Class 1 models are those recommended to be used a priori in the * reduction of raw space geodetic data in order to determine * geodetic parameter estimates. * Class 2 models are those that eliminate an observational * singularity and are purely conventional in nature. * Class 3 models are those that are not required as either Class * 1 or 2. * Canonical models are accepted as is and cannot be classified as a * Class 1, 2, or 3 model. * * Given: * T d TT, Julian centuries since J2000 (Note 1) * * Returned: * L d Mean anomaly of the Moon (Note 2) * LP d Mean anomaly of the Sun (Note 2) * F d L - OM (Notes 2 and 3) * D d Mean elongation of the Moon from the Sun * (Note 2) * OM d Mean longitude of the ascending node of * the Moon (Note 2) * * Notes: * * 1) Though T is strictly TDB, it is usually more convenient to use * TT, which makes no significant difference. Julian centuries since * J2000 is (JD - 2451545.0)/36525. * * 2) The expression used is as adopted in IERS Conventions (2010) and * is from Simon et al. (1994). Arguments are in radians. * * 3) L in this instance is the Mean Longitude of the Moon. OM is the * Mean longitude of the ascending node of the Moon. * * Test case: * given input: T = 0.07995893223819302 Julian centuries since J2000 * (MJD = 54465) * expected output: L = 2.291187512612069099 radians * LP = 6.212931111003726414 radians * F = 3.658025792050572989 radians * D = 4.554139562402433228 radians * OM = -0.5167379217231804489 radians * * References: * * Simon, J.-L., Bretagnon, P., Chapront, J., Chapront-Touze, M., * Francou, G., Laskar, J., 1994, Astron.Astrophys. 282, 663-683 * * Petit, G. and Luzum, B. (eds.), IERS Conventions (2010), * IERS Technical Note No. 36, BKG (2010) * * Revisions: * 2008 January 18 B.E.Stetzler Initial changes to header * and used 2PI instead of PI as parameter * 2008 January 25 B.E. Stetzler Additional changes to header * and defined fundamental arguments * 2008 January 28 B.E. Stetzler Additional changes to header * 2008 March 12 B.E. Stetzler Applied changes to wording of notes. * 2008 April 03 B.E. Stetzler Provided example test case. * 2009 February 11 B.E. Stetzler Corrected term in OM from 6962890.2665 * to 6962890.5431 and updated test case * 2009 May 07 B.E. Stetzler Code formatting changes based on * client recommendations * 2009 May 07 B.E. Stetzler Updated test case due to above changes * 2010 February 25 B.E. Stetzler Recalculation of fundamental arguments *----------------------------------------------------------------------- IMPLICIT NONE DOUBLE PRECISION T, L, LP, F, D, OM * Arcseconds to radians DOUBLE PRECISION DAS2R PARAMETER ( DAS2R = 4.848136811095359935899141D-6 ) * Arcseconds in a full circle DOUBLE PRECISION TURNAS PARAMETER ( TURNAS = 1296000D0 ) * 2Pi DOUBLE PRECISION D2PI PARAMETER ( D2PI = 6.283185307179586476925287D0 ) * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * Compute the fundamental argument L. L = MOD ( 485868.249036D0 + . T*( 1717915923.2178D0 + . T*( 31.8792D0 + . T*( 0.051635D0 + . T*( - 0.00024470D0 )))), TURNAS ) * DAS2R * Compute the fundamental argument LP. LP = MOD ( 1287104.79305D0 + . T*( 129596581.0481D0 + . T*( - 0.5532D0 + . T*( 0.000136D0 + . T*( - 0.00001149D0 )))), TURNAS ) * DAS2R * Compute the fundamental argument F. F = MOD ( 335779.526232D0 + . T*( 1739527262.8478D0 + . T*( - 12.7512D0 + . T*( - 0.001037D0 + . T*( 0.00000417D0 )))), TURNAS ) * DAS2R * Compute the fundamental argument D. D = MOD ( 1072260.70369D0 + . T*( 1602961601.2090D0 + . T*( - 6.3706D0 + . T*( 0.006593D0 + . T*( - 0.00003169D0 )))), TURNAS ) * DAS2R * Compute the fundamental argument OM. OM = MOD ( 450160.398036D0 + . T*( - 6962890.5431D0 + . T*( 7.4722D0 + . T*( 0.007702D0 + . T*( - 0.00005939D0 )))), TURNAS ) * DAS2R * Finished. *+---------------------------------------------------------------------- * * Copyright (C) 2008 * IERS Conventions Center * * ================================== * IERS Conventions Software License * ================================== * * NOTICE TO USER: * * BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING TERMS AND CONDITIONS * WHICH APPLY TO ITS USE. * * 1. The Software is provided by the IERS Conventions Center ("the * Center"). * * 2. 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