FACT++  1.0
bp00.c
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1 #include "erfa.h"
2 
3 void eraBp00(double date1, double date2,
4  double rb[3][3], double rp[3][3], double rbp[3][3])
5 /*
6 ** - - - - - - - -
7 ** e r a B p 0 0
8 ** - - - - - - - -
9 **
10 ** Frame bias and precession, IAU 2000.
11 **
12 ** Given:
13 ** date1,date2 double TT as a 2-part Julian Date (Note 1)
14 **
15 ** Returned:
16 ** rb double[3][3] frame bias matrix (Note 2)
17 ** rp double[3][3] precession matrix (Note 3)
18 ** rbp double[3][3] bias-precession matrix (Note 4)
19 **
20 ** Notes:
21 **
22 ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
23 ** convenient way between the two arguments. For example,
24 ** JD(TT)=2450123.7 could be expressed in any of these ways,
25 ** among others:
26 **
27 ** date1 date2
28 **
29 ** 2450123.7 0.0 (JD method)
30 ** 2451545.0 -1421.3 (J2000 method)
31 ** 2400000.5 50123.2 (MJD method)
32 ** 2450123.5 0.2 (date & time method)
33 **
34 ** The JD method is the most natural and convenient to use in
35 ** cases where the loss of several decimal digits of resolution
36 ** is acceptable. The J2000 method is best matched to the way
37 ** the argument is handled internally and will deliver the
38 ** optimum resolution. The MJD method and the date & time methods
39 ** are both good compromises between resolution and convenience.
40 **
41 ** 2) The matrix rb transforms vectors from GCRS to mean J2000.0 by
42 ** applying frame bias.
43 **
44 ** 3) The matrix rp transforms vectors from J2000.0 mean equator and
45 ** equinox to mean equator and equinox of date by applying
46 ** precession.
47 **
48 ** 4) The matrix rbp transforms vectors from GCRS to mean equator and
49 ** equinox of date by applying frame bias then precession. It is
50 ** the product rp x rb.
51 **
52 ** 5) It is permissible to re-use the same array in the returned
53 ** arguments. The arrays are filled in the order given.
54 **
55 ** Called:
56 ** eraBi00 frame bias components, IAU 2000
57 ** eraPr00 IAU 2000 precession adjustments
58 ** eraIr initialize r-matrix to identity
59 ** eraRx rotate around X-axis
60 ** eraRy rotate around Y-axis
61 ** eraRz rotate around Z-axis
62 ** eraCr copy r-matrix
63 ** eraRxr product of two r-matrices
64 **
65 ** Reference:
66 ** "Expressions for the Celestial Intermediate Pole and Celestial
67 ** Ephemeris Origin consistent with the IAU 2000A precession-
68 ** nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
69 **
70 ** n.b. The celestial ephemeris origin (CEO) was renamed "celestial
71 ** intermediate origin" (CIO) by IAU 2006 Resolution 2.
72 **
73 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
74 ** Derived, with permission, from the SOFA library. See notes at end of file.
75 */
76 {
77 /* J2000.0 obliquity (Lieske et al. 1977) */
78  const double EPS0 = 84381.448 * ERFA_DAS2R;
79 
80  double t, dpsibi, depsbi, dra0, psia77, oma77, chia,
81  dpsipr, depspr, psia, oma, rbw[3][3];
82 
83 /* Interval between fundamental epoch J2000.0 and current date (JC). */
84  t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
85 
86 /* Frame bias. */
87  eraBi00(&dpsibi, &depsbi, &dra0);
88 
89 /* Precession angles (Lieske et al. 1977) */
90  psia77 = (5038.7784 + (-1.07259 + (-0.001147) * t) * t) * t * ERFA_DAS2R;
91  oma77 = EPS0 + ((0.05127 + (-0.007726) * t) * t) * t * ERFA_DAS2R;
92  chia = ( 10.5526 + (-2.38064 + (-0.001125) * t) * t) * t * ERFA_DAS2R;
93 
94 /* Apply IAU 2000 precession corrections. */
95  eraPr00(date1, date2, &dpsipr, &depspr);
96  psia = psia77 + dpsipr;
97  oma = oma77 + depspr;
98 
99 /* Frame bias matrix: GCRS to J2000.0. */
100  eraIr(rbw);
101  eraRz(dra0, rbw);
102  eraRy(dpsibi*sin(EPS0), rbw);
103  eraRx(-depsbi, rbw);
104  eraCr(rbw, rb);
105 
106 /* Precession matrix: J2000.0 to mean of date. */
107  eraIr(rp);
108  eraRx(EPS0, rp);
109  eraRz(-psia, rp);
110  eraRx(-oma, rp);
111  eraRz(chia, rp);
112 
113 /* Bias-precession matrix: GCRS to mean of date. */
114  eraRxr(rp, rbw, rbp);
115 
116  return;
117 
118 }
119 /*----------------------------------------------------------------------
120 **
121 **
122 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
123 ** All rights reserved.
124 **
125 ** This library is derived, with permission, from the International
126 ** Astronomical Union's "Standards of Fundamental Astronomy" library,
127 ** available from http://www.iausofa.org.
128 **
129 ** The ERFA version is intended to retain identical functionality to
130 ** the SOFA library, but made distinct through different function and
131 ** file names, as set out in the SOFA license conditions. The SOFA
132 ** original has a role as a reference standard for the IAU and IERS,
133 ** and consequently redistribution is permitted only in its unaltered
134 ** state. The ERFA version is not subject to this restriction and
135 ** therefore can be included in distributions which do not support the
136 ** concept of "read only" software.
137 **
138 ** Although the intent is to replicate the SOFA API (other than
139 ** replacement of prefix names) and results (with the exception of
140 ** bugs; any that are discovered will be fixed), SOFA is not
141 ** responsible for any errors found in this version of the library.
142 **
143 ** If you wish to acknowledge the SOFA heritage, please acknowledge
144 ** that you are using a library derived from SOFA, rather than SOFA
145 ** itself.
146 **
147 **
148 ** TERMS AND CONDITIONS
149 **
150 ** Redistribution and use in source and binary forms, with or without
151 ** modification, are permitted provided that the following conditions
152 ** are met:
153 **
154 ** 1 Redistributions of source code must retain the above copyright
155 ** notice, this list of conditions and the following disclaimer.
156 **
157 ** 2 Redistributions in binary form must reproduce the above copyright
158 ** notice, this list of conditions and the following disclaimer in
159 ** the documentation and/or other materials provided with the
160 ** distribution.
161 **
162 ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
163 ** the International Astronomical Union nor the names of its
164 ** contributors may be used to endorse or promote products derived
165 ** from this software without specific prior written permission.
166 **
167 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
168 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
169 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
170 ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
171 ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
172 ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
173 ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
174 ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
175 ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
176 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
177 ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
178 ** POSSIBILITY OF SUCH DAMAGE.
179 **
180 */
ERFA_DJ00
#define ERFA_DJ00
Definition: erfam.h:87
ERFA_DAS2R
#define ERFA_DAS2R
Definition: erfam.h:60
eraRx
void eraRx(double phi, double r[3][3])
Definition: rx.c:3
eraCr
void eraCr(double r[3][3], double c[3][3])
Definition: cr.c:3
eraIr
void eraIr(double r[3][3])
Definition: ir.c:3
eraRxr
void eraRxr(double a[3][3], double b[3][3], double atb[3][3])
Definition: rxr.c:3
eraRy
void eraRy(double theta, double r[3][3])
Definition: ry.c:3
eraRz
void eraRz(double psi, double r[3][3])
Definition: rz.c:3
ERFA_DJC
#define ERFA_DJC
Definition: erfam.h:81
eraBi00
void eraBi00(double *dpsibi, double *depsbi, double *dra)
Definition: bi00.c:3
eraBp00
void eraBp00(double date1, double date2, double rb[3][3], double rp[3][3], double rbp[3][3])
Definition: bp00.c:3
t
TT t
Definition: test_client.c:26
eraPr00
void eraPr00(double date1, double date2, double *dpsipr, double *depspr)
Definition: pr00.c:3