File Coverage

erfasrc/src/apcg13.c

Criterion	Covered	Total	%
statement	0	4	0.0
branch			n/a
condition			n/a
subroutine			n/a
pod			n/a
total	0	4	0.0

line	stmt	code
1		#include "erfa.h"
2
3	0	void eraApcg13(double date1, double date2, eraASTROM *astrom)
4		/*
5		** - - - - - - - - - -
6		** e r a A p c g 1 3
7		** - - - - - - - - - -
8		**
9		** For a geocentric observer, prepare star-independent astrometry
10		** parameters for transformations between ICRS and GCRS coordinates.
11		** The caller supplies the date, and ERFA models are used to predict
12		** the Earth ephemeris.
13		**
14		** The parameters produced by this function are required in the
15		** parallax, light deflection and aberration parts of the astrometric
16		** transformation chain.
17		**
18		** Given:
19		** date1 double TDB as a 2-part...
20		** date2 double ...Julian Date (Note 1)
21		**
22		** Returned:
23		** astrom eraASTROM* star-independent astrometry parameters:
24		** pmt double PM time interval (SSB, Julian years)
25		** eb double[3] SSB to observer (vector, au)
26		** eh double[3] Sun to observer (unit vector)
27		** em double distance from Sun to observer (au)
28		** v double[3] barycentric observer velocity (vector, c)
29		** bm1 double sqrt(1-\|v\|^2): reciprocal of Lorenz factor
30		** bpn double[3][3] bias-precession-nutation matrix
31		** along double unchanged
32		** xpl double unchanged
33		** ypl double unchanged
34		** sphi double unchanged
35		** cphi double unchanged
36		** diurab double unchanged
37		** eral double unchanged
38		** refa double unchanged
39		** refb double unchanged
40		**
41		** Notes:
42		**
43		** 1) The TDB date date1+date2 is a Julian Date, apportioned in any
44		** convenient way between the two arguments. For example,
45		** JD(TDB)=2450123.7 could be expressed in any of these ways, among
46		** others:
47		**
48		** date1 date2
49		**
50		** 2450123.7 0.0 (JD method)
51		** 2451545.0 -1421.3 (J2000 method)
52		** 2400000.5 50123.2 (MJD method)
53		** 2450123.5 0.2 (date & time method)
54		**
55		** The JD method is the most natural and convenient to use in cases
56		** where the loss of several decimal digits of resolution is
57		** acceptable. The J2000 method is best matched to the way the
58		** argument is handled internally and will deliver the optimum
59		** resolution. The MJD method and the date & time methods are both
60		** good compromises between resolution and convenience. For most
61		** applications of this function the choice will not be at all
62		** critical.
63		**
64		** TT can be used instead of TDB without any significant impact on
65		** accuracy.
66		**
67		** 2) All the vectors are with respect to BCRS axes.
68		**
69		** 3) In cases where the caller wishes to supply his own Earth
70		** ephemeris, the function eraApcg can be used instead of the present
71		** function.
72		**
73		** 4) This is one of several functions that inserts into the astrom
74		** structure star-independent parameters needed for the chain of
75		** astrometric transformations ICRS <-> GCRS <-> CIRS <-> observed.
76		**
77		** The various functions support different classes of observer and
78		** portions of the transformation chain:
79		**
80		** functions observer transformation
81		**
82		** eraApcg eraApcg13 geocentric ICRS <-> GCRS
83		** eraApci eraApci13 terrestrial ICRS <-> CIRS
84		** eraApco eraApco13 terrestrial ICRS <-> observed
85		** eraApcs eraApcs13 space ICRS <-> GCRS
86		** eraAper eraAper13 terrestrial update Earth rotation
87		** eraApio eraApio13 terrestrial CIRS <-> observed
88		**
89		** Those with names ending in "13" use contemporary ERFA models to
90		** compute the various ephemerides. The others accept ephemerides
91		** supplied by the caller.
92		**
93		** The transformation from ICRS to GCRS covers space motion,
94		** parallax, light deflection, and aberration. From GCRS to CIRS
95		** comprises frame bias and precession-nutation. From CIRS to
96		** observed takes account of Earth rotation, polar motion, diurnal
97		** aberration and parallax (unless subsumed into the ICRS <-> GCRS
98		** transformation), and atmospheric refraction.
99		**
100		** 5) The context structure astrom produced by this function is used by
101		** eraAtciq* and eraAticq*.
102		**
103		** Called:
104		** eraEpv00 Earth position and velocity
105		** eraApcg astrometry parameters, ICRS-GCRS, geocenter
106		**
107		** Copyright (C) 2013-2020, NumFOCUS Foundation.
108		** Derived, with permission, from the SOFA library. See notes at end of file.
109		*/
110		{
111		double ehpv[2][3], ebpv[2][3];
112
113
114		/* Earth barycentric & heliocentric position/velocity (au, au/d). */
115	0	(void) eraEpv00(date1, date2, ehpv, ebpv);
116
117		/* Compute the star-independent astrometry parameters. */
118	0	eraApcg(date1, date2, ebpv, ehpv[0], astrom);
119
120		/* Finished. */
121
122	0	}
123		/*----------------------------------------------------------------------
124		**
125		**
126		** Copyright (C) 2013-2020, NumFOCUS Foundation.
127		** All rights reserved.
128		**
129		** This library is derived, with permission, from the International
130		** Astronomical Union's "Standards of Fundamental Astronomy" library,
131		** available from http://www.iausofa.org.
132		**
133		** The ERFA version is intended to retain identical functionality to
134		** the SOFA library, but made distinct through different function and
135		** file names, as set out in the SOFA license conditions. The SOFA
136		** original has a role as a reference standard for the IAU and IERS,
137		** and consequently redistribution is permitted only in its unaltered
138		** state. The ERFA version is not subject to this restriction and
139		** therefore can be included in distributions which do not support the
140		** concept of "read only" software.
141		**
142		** Although the intent is to replicate the SOFA API (other than
143		** replacement of prefix names) and results (with the exception of
144		** bugs; any that are discovered will be fixed), SOFA is not
145		** responsible for any errors found in this version of the library.
146		**
147		** If you wish to acknowledge the SOFA heritage, please acknowledge
148		** that you are using a library derived from SOFA, rather than SOFA
149		** itself.
150		**
151		**
152		** TERMS AND CONDITIONS
153		**
154		** Redistribution and use in source and binary forms, with or without
155		** modification, are permitted provided that the following conditions
156		** are met:
157		**
158		** 1 Redistributions of source code must retain the above copyright
159		** notice, this list of conditions and the following disclaimer.
160		**
161		** 2 Redistributions in binary form must reproduce the above copyright
162		** notice, this list of conditions and the following disclaimer in
163		** the documentation and/or other materials provided with the
164		** distribution.
165		**
166		** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
167		** the International Astronomical Union nor the names of its
168		** contributors may be used to endorse or promote products derived
169		** from this software without specific prior written permission.
170		**
171		** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
172		** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
173		** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
174		** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
175		** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
176		** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
177		** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
178		** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
179		** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
180		** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
181		** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
182		** POSSIBILITY OF SUCH DAMAGE.
183		**
184		*/