source: trunk/FACT++/sofa/src/pn06.c@ 18355

Last change on this file since 18355 was 18346, checked in by tbretz, 11 years ago
File size: 9.0 KB
Line 
1#include "sofa.h"
2
3void iauPn06(double date1, double date2, double dpsi, double deps,
4 double *epsa,
5 double rb[3][3], double rp[3][3], double rbp[3][3],
6 double rn[3][3], double rbpn[3][3])
7/*
8** - - - - - - - -
9** i a u P n 0 6
10** - - - - - - - -
11**
12** Precession-nutation, IAU 2006 model: a multi-purpose function,
13** supporting classical (equinox-based) use directly and CIO-based use
14** indirectly.
15**
16** This function is part of the International Astronomical Union's
17** SOFA (Standards Of Fundamental Astronomy) software collection.
18**
19** Status: support function.
20**
21** Given:
22** date1,date2 double TT as a 2-part Julian Date (Note 1)
23** dpsi,deps double nutation (Note 2)
24**
25** Returned:
26** epsa double mean obliquity (Note 3)
27** rb double[3][3] frame bias matrix (Note 4)
28** rp double[3][3] precession matrix (Note 5)
29** rbp double[3][3] bias-precession matrix (Note 6)
30** rn double[3][3] nutation matrix (Note 7)
31** rbpn double[3][3] GCRS-to-true matrix (Note 8)
32**
33** Notes:
34**
35** 1) The TT date date1+date2 is a Julian Date, apportioned in any
36** convenient way between the two arguments. For example,
37** JD(TT)=2450123.7 could be expressed in any of these ways,
38** among others:
39**
40** date1 date2
41**
42** 2450123.7 0.0 (JD method)
43** 2451545.0 -1421.3 (J2000 method)
44** 2400000.5 50123.2 (MJD method)
45** 2450123.5 0.2 (date & time method)
46**
47** The JD method is the most natural and convenient to use in
48** cases where the loss of several decimal digits of resolution
49** is acceptable. The J2000 method is best matched to the way
50** the argument is handled internally and will deliver the
51** optimum resolution. The MJD method and the date & time methods
52** are both good compromises between resolution and convenience.
53**
54** 2) The caller is responsible for providing the nutation components;
55** they are in longitude and obliquity, in radians and are with
56** respect to the equinox and ecliptic of date. For high-accuracy
57** applications, free core nutation should be included as well as
58** any other relevant corrections to the position of the CIP.
59**
60** 3) The returned mean obliquity is consistent with the IAU 2006
61** precession.
62**
63** 4) The matrix rb transforms vectors from GCRS to J2000.0 mean
64** equator and equinox by applying frame bias.
65**
66** 5) The matrix rp transforms vectors from J2000.0 mean equator and
67** equinox to mean equator and equinox of date by applying
68** precession.
69**
70** 6) The matrix rbp transforms vectors from GCRS to mean equator and
71** equinox of date by applying frame bias then precession. It is
72** the product rp x rb.
73**
74** 7) The matrix rn transforms vectors from mean equator and equinox
75** of date to true equator and equinox of date by applying the
76** nutation (luni-solar + planetary).
77**
78** 8) The matrix rbpn transforms vectors from GCRS to true equator and
79** equinox of date. It is the product rn x rbp, applying frame
80** bias, precession and nutation in that order.
81**
82** 9) The X,Y,Z coordinates of the Celestial Intermediate Pole are
83** elements (3,1-3) of the GCRS-to-true matrix, i.e. rbpn[2][0-2].
84**
85** 10) It is permissible to re-use the same array in the returned
86** arguments. The arrays are filled in the stated order.
87**
88** Called:
89** iauPfw06 bias-precession F-W angles, IAU 2006
90** iauFw2m F-W angles to r-matrix
91** iauCr copy r-matrix
92** iauTr transpose r-matrix
93** iauRxr product of two r-matrices
94**
95** References:
96**
97** Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855
98**
99** Wallace, P.T. & Capitaine, N., 2006, Astron.Astrophys. 459, 981
100**
101** This revision: 2013 November 14
102**
103** SOFA release 2015-02-09
104**
105** Copyright (C) 2015 IAU SOFA Board. See notes at end.
106*/
107{
108 double gamb, phib, psib, eps, r1[3][3], r2[3][3], rt[3][3];
109
110/* Bias-precession Fukushima-Williams angles of J2000.0 = frame bias. */
111 iauPfw06(DJM0, DJM00, &gamb, &phib, &psib, &eps);
112
113/* B matrix. */
114 iauFw2m(gamb, phib, psib, eps, r1);
115 iauCr(r1, rb);
116
117/* Bias-precession Fukushima-Williams angles of date. */
118 iauPfw06(date1, date2, &gamb, &phib, &psib, &eps);
119
120/* Bias-precession matrix. */
121 iauFw2m(gamb, phib, psib, eps, r2);
122 iauCr(r2, rbp);
123
124/* Solve for precession matrix. */
125 iauTr(r1, rt);
126 iauRxr(r2, rt, rp);
127
128/* Equinox-based bias-precession-nutation matrix. */
129 iauFw2m(gamb, phib, psib + dpsi, eps + deps, r1);
130 iauCr(r1, rbpn);
131
132/* Solve for nutation matrix. */
133 iauTr(r2, rt);
134 iauRxr(r1, rt, rn);
135
136/* Obliquity, mean of date. */
137 *epsa = eps;
138
139 return;
140
141/*----------------------------------------------------------------------
142**
143** Copyright (C) 2015
144** Standards Of Fundamental Astronomy Board
145** of the International Astronomical Union.
146**
147** =====================
148** SOFA Software License
149** =====================
150**
151** NOTICE TO USER:
152**
153** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
154** CONDITIONS WHICH APPLY TO ITS USE.
155**
156** 1. The Software is owned by the IAU SOFA Board ("SOFA").
157**
158** 2. Permission is granted to anyone to use the SOFA software for any
159** purpose, including commercial applications, free of charge and
160** without payment of royalties, subject to the conditions and
161** restrictions listed below.
162**
163** 3. You (the user) may copy and distribute SOFA source code to others,
164** and use and adapt its code and algorithms in your own software,
165** on a world-wide, royalty-free basis. That portion of your
166** distribution that does not consist of intact and unchanged copies
167** of SOFA source code files is a "derived work" that must comply
168** with the following requirements:
169**
170** a) Your work shall be marked or carry a statement that it
171** (i) uses routines and computations derived by you from
172** software provided by SOFA under license to you; and
173** (ii) does not itself constitute software provided by and/or
174** endorsed by SOFA.
175**
176** b) The source code of your derived work must contain descriptions
177** of how the derived work is based upon, contains and/or differs
178** from the original SOFA software.
179**
180** c) The names of all routines in your derived work shall not
181** include the prefix "iau" or "sofa" or trivial modifications
182** thereof such as changes of case.
183**
184** d) The origin of the SOFA components of your derived work must
185** not be misrepresented; you must not claim that you wrote the
186** original software, nor file a patent application for SOFA
187** software or algorithms embedded in the SOFA software.
188**
189** e) These requirements must be reproduced intact in any source
190** distribution and shall apply to anyone to whom you have
191** granted a further right to modify the source code of your
192** derived work.
193**
194** Note that, as originally distributed, the SOFA software is
195** intended to be a definitive implementation of the IAU standards,
196** and consequently third-party modifications are discouraged. All
197** variations, no matter how minor, must be explicitly marked as
198** such, as explained above.
199**
200** 4. You shall not cause the SOFA software to be brought into
201** disrepute, either by misuse, or use for inappropriate tasks, or
202** by inappropriate modification.
203**
204** 5. The SOFA software is provided "as is" and SOFA makes no warranty
205** as to its use or performance. SOFA does not and cannot warrant
206** the performance or results which the user may obtain by using the
207** SOFA software. SOFA makes no warranties, express or implied, as
208** to non-infringement of third party rights, merchantability, or
209** fitness for any particular purpose. In no event will SOFA be
210** liable to the user for any consequential, incidental, or special
211** damages, including any lost profits or lost savings, even if a
212** SOFA representative has been advised of such damages, or for any
213** claim by any third party.
214**
215** 6. The provision of any version of the SOFA software under the terms
216** and conditions specified herein does not imply that future
217** versions will also be made available under the same terms and
218** conditions.
219*
220** In any published work or commercial product which uses the SOFA
221** software directly, acknowledgement (see www.iausofa.org) is
222** appreciated.
223**
224** Correspondence concerning SOFA software should be addressed as
225** follows:
226**
227** By email: sofa@ukho.gov.uk
228** By post: IAU SOFA Center
229** HM Nautical Almanac Office
230** UK Hydrographic Office
231** Admiralty Way, Taunton
232** Somerset, TA1 2DN
233** United Kingdom
234**
235**--------------------------------------------------------------------*/
236}
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