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. Permission is granted to anyone to use the Software for any
* purpose, including commercial applications, free of charge,
* subject to the conditions and restrictions listed below.
*
* 3. You (the user) may adapt the Software and its algorithms for your
* own purposes and you may distribute the resulting "derived work"
* to others, provided that the derived work complies with the
* following requirements:
*
* a) Your work shall be clearly identified so that it cannot be
* mistaken for IERS Conventions software and that it has been
* neither distributed by nor endorsed by the Center.
*
* b) Your work (including source code) must contain descriptions of
* how the derived work is based upon and/or differs from the
* original Software.
*
* c) The name(s) of all modified routine(s) that you distribute
* shall be changed.
*
* d) The origin of the IERS Conventions components of your derived
* work must not be misrepresented; you must not claim that you
* wrote the original Software.
*
* e) The source code must be included for all routine(s) that you
* distribute. This notice must be reproduced intact in any
* source distribution.
*
* 4. In any published work produced by the user and which includes
* results achieved by using the Software, you shall acknowledge
* that the Software was used in obtaining those results.
*
* 5. The Software is provided to the user "as is" and the Center makes
* no warranty as to its use or performance. The Center does not
* and cannot warrant the performance or results which the user may
* obtain by using the Software. The Center makes no warranties,
* express or implied, as to non-infringement of third party rights,
* merchantability, or fitness for any particular purpose. In no
* event will the Center be liable to the user for any consequential,
* incidental, or special damages, including any lost profits or lost
* savings, even if a Center representative has been advised of such
* damages, or for any claim by any third party.
*
* Correspondence concerning IERS Conventions software should be
* addressed as follows:
*
* Gerard Petit
* Internet email: gpetit[at]bipm.org
* Postal address: IERS Conventions Center
* Time, frequency and gravimetry section, BIPM
* Pavillon de Breteuil
* 92312 Sevres FRANCE
*
* or
*
* Brian Luzum
* Internet email: brian.luzum[at]usno.navy.mil
* Postal address: IERS Conventions Center
* Earth Orientation Department
* 3450 Massachusetts Ave, NW
* Washington, DC 20392
*
*
*-----------------------------------------------------------------------
END