source: trunk/FACT++/erfa/src/c2tpe.c@ 19594

Last change on this file since 19594 was 18921, checked in by tbretz, 8 years ago
Updated to ERFA 1.4.0
File size: 7.2 KB
Line 
1#include "erfa.h"
2
3void eraC2tpe(double tta, double ttb, double uta, double utb,
4 double dpsi, double deps, double xp, double yp,
5 double rc2t[3][3])
6/*
7** - - - - - - - - -
8** e r a C 2 t p e
9** - - - - - - - - -
10**
11** Form the celestial to terrestrial matrix given the date, the UT1,
12** the nutation and the polar motion. IAU 2000.
13**
14** Given:
15** tta,ttb double TT as a 2-part Julian Date (Note 1)
16** uta,utb double UT1 as a 2-part Julian Date (Note 1)
17** dpsi,deps double nutation (Note 2)
18** xp,yp double coordinates of the pole (radians, Note 3)
19**
20** Returned:
21** rc2t double[3][3] celestial-to-terrestrial matrix (Note 4)
22**
23** Notes:
24**
25** 1) The TT and UT1 dates tta+ttb and uta+utb are Julian Dates,
26** apportioned in any convenient way between the arguments uta and
27** utb. For example, JD(UT1)=2450123.7 could be expressed in any of
28** these ways, among others:
29**
30** uta utb
31**
32** 2450123.7 0.0 (JD method)
33** 2451545.0 -1421.3 (J2000 method)
34** 2400000.5 50123.2 (MJD method)
35** 2450123.5 0.2 (date & time method)
36**
37** The JD method is the most natural and convenient to use in
38** cases where the loss of several decimal digits of resolution is
39** acceptable. The J2000 and MJD methods are good compromises
40** between resolution and convenience. In the case of uta,utb, the
41** date & time method is best matched to the Earth rotation angle
42** algorithm used: maximum precision is delivered when the uta
43** argument is for 0hrs UT1 on the day in question and the utb
44** argument lies in the range 0 to 1, or vice versa.
45**
46** 2) The caller is responsible for providing the nutation components;
47** they are in longitude and obliquity, in radians and are with
48** respect to the equinox and ecliptic of date. For high-accuracy
49** applications, free core nutation should be included as well as
50** any other relevant corrections to the position of the CIP.
51**
52** 3) The arguments xp and yp are the coordinates (in radians) of the
53** Celestial Intermediate Pole with respect to the International
54** Terrestrial Reference System (see IERS Conventions 2003),
55** measured along the meridians to 0 and 90 deg west respectively.
56**
57** 4) The matrix rc2t transforms from celestial to terrestrial
58** coordinates:
59**
60** [TRS] = RPOM * R_3(GST) * RBPN * [CRS]
61**
62** = rc2t * [CRS]
63**
64** where [CRS] is a vector in the Geocentric Celestial Reference
65** System and [TRS] is a vector in the International Terrestrial
66** Reference System (see IERS Conventions 2003), RBPN is the
67** bias-precession-nutation matrix, GST is the Greenwich (apparent)
68** Sidereal Time and RPOM is the polar motion matrix.
69**
70** 5) Although its name does not include "00", This function is in fact
71** specific to the IAU 2000 models.
72**
73** Called:
74** eraPn00 bias/precession/nutation results, IAU 2000
75** eraGmst00 Greenwich mean sidereal time, IAU 2000
76** eraSp00 the TIO locator s', IERS 2000
77** eraEe00 equation of the equinoxes, IAU 2000
78** eraPom00 polar motion matrix
79** eraC2teqx form equinox-based celestial-to-terrestrial matrix
80**
81** Reference:
82**
83** McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
84** IERS Technical Note No. 32, BKG (2004)
85**
86** Copyright (C) 2013-2017, NumFOCUS Foundation.
87** Derived, with permission, from the SOFA library. See notes at end of file.
88*/
89{
90 double epsa, rb[3][3], rp[3][3], rbp[3][3], rn[3][3],
91 rbpn[3][3], gmst, ee, sp, rpom[3][3];
92
93
94/* Form the celestial-to-true matrix for this TT. */
95 eraPn00(tta, ttb, dpsi, deps, &epsa, rb, rp, rbp, rn, rbpn);
96
97/* Predict the Greenwich Mean Sidereal Time for this UT1 and TT. */
98 gmst = eraGmst00(uta, utb, tta, ttb);
99
100/* Predict the equation of the equinoxes given TT and nutation. */
101 ee = eraEe00(tta, ttb, epsa, dpsi);
102
103/* Estimate s'. */
104 sp = eraSp00(tta, ttb);
105
106/* Form the polar motion matrix. */
107 eraPom00(xp, yp, sp, rpom);
108
109/* Combine to form the celestial-to-terrestrial matrix. */
110 eraC2teqx(rbpn, gmst + ee, rpom, rc2t);
111
112 return;
113
114}
115/*----------------------------------------------------------------------
116**
117**
118** Copyright (C) 2013-2017, NumFOCUS Foundation.
119** All rights reserved.
120**
121** This library is derived, with permission, from the International
122** Astronomical Union's "Standards of Fundamental Astronomy" library,
123** available from http://www.iausofa.org.
124**
125** The ERFA version is intended to retain identical functionality to
126** the SOFA library, but made distinct through different function and
127** file names, as set out in the SOFA license conditions. The SOFA
128** original has a role as a reference standard for the IAU and IERS,
129** and consequently redistribution is permitted only in its unaltered
130** state. The ERFA version is not subject to this restriction and
131** therefore can be included in distributions which do not support the
132** concept of "read only" software.
133**
134** Although the intent is to replicate the SOFA API (other than
135** replacement of prefix names) and results (with the exception of
136** bugs; any that are discovered will be fixed), SOFA is not
137** responsible for any errors found in this version of the library.
138**
139** If you wish to acknowledge the SOFA heritage, please acknowledge
140** that you are using a library derived from SOFA, rather than SOFA
141** itself.
142**
143**
144** TERMS AND CONDITIONS
145**
146** Redistribution and use in source and binary forms, with or without
147** modification, are permitted provided that the following conditions
148** are met:
149**
150** 1 Redistributions of source code must retain the above copyright
151** notice, this list of conditions and the following disclaimer.
152**
153** 2 Redistributions in binary form must reproduce the above copyright
154** notice, this list of conditions and the following disclaimer in
155** the documentation and/or other materials provided with the
156** distribution.
157**
158** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
159** the International Astronomical Union nor the names of its
160** contributors may be used to endorse or promote products derived
161** from this software without specific prior written permission.
162**
163** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
164** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
165** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
166** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
167** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
168** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
169** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
170** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
171** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
172** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
173** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
174** POSSIBILITY OF SUCH DAMAGE.
175**
176*/
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