source: trunk/FACT++/erfa/src/pn06.c@ 18403

Last change on this file since 18403 was 18348, checked in by tbretz, 9 years ago
File size: 7.6 KB
Line 
1#include "erfa.h"
2
3void eraPn06(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** e r a 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** Given:
17** date1,date2 double TT as a 2-part Julian Date (Note 1)
18** dpsi,deps double nutation (Note 2)
19**
20** Returned:
21** epsa double mean obliquity (Note 3)
22** rb double[3][3] frame bias matrix (Note 4)
23** rp double[3][3] precession matrix (Note 5)
24** rbp double[3][3] bias-precession matrix (Note 6)
25** rn double[3][3] nutation matrix (Note 7)
26** rbpn double[3][3] GCRS-to-true matrix (Note 8)
27**
28** Notes:
29**
30** 1) The TT date date1+date2 is a Julian Date, apportioned in any
31** convenient way between the two arguments. For example,
32** JD(TT)=2450123.7 could be expressed in any of these ways,
33** among others:
34**
35** date1 date2
36**
37** 2450123.7 0.0 (JD method)
38** 2451545.0 -1421.3 (J2000 method)
39** 2400000.5 50123.2 (MJD method)
40** 2450123.5 0.2 (date & time method)
41**
42** The JD method is the most natural and convenient to use in
43** cases where the loss of several decimal digits of resolution
44** is acceptable. The J2000 method is best matched to the way
45** the argument is handled internally and will deliver the
46** optimum resolution. The MJD method and the date & time methods
47** are both good compromises between resolution and convenience.
48**
49** 2) The caller is responsible for providing the nutation components;
50** they are in longitude and obliquity, in radians and are with
51** respect to the equinox and ecliptic of date. For high-accuracy
52** applications, free core nutation should be included as well as
53** any other relevant corrections to the position of the CIP.
54**
55** 3) The returned mean obliquity is consistent with the IAU 2006
56** precession.
57**
58** 4) The matrix rb transforms vectors from GCRS to J2000.0 mean
59** equator and equinox by applying frame bias.
60**
61** 5) The matrix rp transforms vectors from J2000.0 mean equator and
62** equinox to mean equator and equinox of date by applying
63** precession.
64**
65** 6) The matrix rbp transforms vectors from GCRS to mean equator and
66** equinox of date by applying frame bias then precession. It is
67** the product rp x rb.
68**
69** 7) The matrix rn transforms vectors from mean equator and equinox
70** of date to true equator and equinox of date by applying the
71** nutation (luni-solar + planetary).
72**
73** 8) The matrix rbpn transforms vectors from GCRS to true equator and
74** equinox of date. It is the product rn x rbp, applying frame
75** bias, precession and nutation in that order.
76**
77** 9) The X,Y,Z coordinates of the Celestial Intermediate Pole are
78** elements (3,1-3) of the GCRS-to-true matrix, i.e. rbpn[2][0-2].
79**
80** 10) It is permissible to re-use the same array in the returned
81** arguments. The arrays are filled in the stated order.
82**
83** Called:
84** eraPfw06 bias-precession F-W angles, IAU 2006
85** eraFw2m F-W angles to r-matrix
86** eraCr copy r-matrix
87** eraTr transpose r-matrix
88** eraRxr product of two r-matrices
89**
90** References:
91**
92** Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855
93**
94** Wallace, P.T. & Capitaine, N., 2006, Astron.Astrophys. 459, 981
95**
96** Copyright (C) 2013-2015, NumFOCUS Foundation.
97** Derived, with permission, from the SOFA library. See notes at end of file.
98*/
99{
100 double gamb, phib, psib, eps, r1[3][3], r2[3][3], rt[3][3];
101
102/* Bias-precession Fukushima-Williams angles of J2000.0 = frame bias. */
103 eraPfw06(ERFA_DJM0, ERFA_DJM00, &gamb, &phib, &psib, &eps);
104
105/* B matrix. */
106 eraFw2m(gamb, phib, psib, eps, r1);
107 eraCr(r1, rb);
108
109/* Bias-precession Fukushima-Williams angles of date. */
110 eraPfw06(date1, date2, &gamb, &phib, &psib, &eps);
111
112/* Bias-precession matrix. */
113 eraFw2m(gamb, phib, psib, eps, r2);
114 eraCr(r2, rbp);
115
116/* Solve for precession matrix. */
117 eraTr(r1, rt);
118 eraRxr(r2, rt, rp);
119
120/* Equinox-based bias-precession-nutation matrix. */
121 eraFw2m(gamb, phib, psib + dpsi, eps + deps, r1);
122 eraCr(r1, rbpn);
123
124/* Solve for nutation matrix. */
125 eraTr(r2, rt);
126 eraRxr(r1, rt, rn);
127
128/* Obliquity, mean of date. */
129 *epsa = eps;
130
131 return;
132
133}
134/*----------------------------------------------------------------------
135**
136**
137** Copyright (C) 2013-2015, NumFOCUS Foundation.
138** All rights reserved.
139**
140** This library is derived, with permission, from the International
141** Astronomical Union's "Standards of Fundamental Astronomy" library,
142** available from http://www.iausofa.org.
143**
144** The ERFA version is intended to retain identical functionality to
145** the SOFA library, but made distinct through different function and
146** file names, as set out in the SOFA license conditions. The SOFA
147** original has a role as a reference standard for the IAU and IERS,
148** and consequently redistribution is permitted only in its unaltered
149** state. The ERFA version is not subject to this restriction and
150** therefore can be included in distributions which do not support the
151** concept of "read only" software.
152**
153** Although the intent is to replicate the SOFA API (other than
154** replacement of prefix names) and results (with the exception of
155** bugs; any that are discovered will be fixed), SOFA is not
156** responsible for any errors found in this version of the library.
157**
158** If you wish to acknowledge the SOFA heritage, please acknowledge
159** that you are using a library derived from SOFA, rather than SOFA
160** itself.
161**
162**
163** TERMS AND CONDITIONS
164**
165** Redistribution and use in source and binary forms, with or without
166** modification, are permitted provided that the following conditions
167** are met:
168**
169** 1 Redistributions of source code must retain the above copyright
170** notice, this list of conditions and the following disclaimer.
171**
172** 2 Redistributions in binary form must reproduce the above copyright
173** notice, this list of conditions and the following disclaimer in
174** the documentation and/or other materials provided with the
175** distribution.
176**
177** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
178** the International Astronomical Union nor the names of its
179** contributors may be used to endorse or promote products derived
180** from this software without specific prior written permission.
181**
182** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
183** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
184** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
185** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
186** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
187** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
188** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
189** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
190** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
191** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
192** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
193** POSSIBILITY OF SUCH DAMAGE.
194**
195*/
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