source: branches/FACT++_lidctrl_usb/erfa/src/c2tpe.c@ 19875

Last change on this file since 19875 was 18711, checked in by tbretz, 10 years ago
Updated to ERFA 1.3.0 (no relevant code change except the leap second at the beginning of 2017)
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) 2013-2016, 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) 2013-2016, 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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