FACT++  1.0
pvtob.c
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1 #include "erfa.h"
2 
3 void eraPvtob(double elong, double phi, double hm,
4  double xp, double yp, double sp, double theta,
5  double pv[2][3])
6 /*
7 ** - - - - - - - - -
8 ** e r a P v t o b
9 ** - - - - - - - - -
10 **
11 ** Position and velocity of a terrestrial observing station.
12 **
13 ** Given:
14 ** elong double longitude (radians, east +ve, Note 1)
15 ** phi double latitude (geodetic, radians, Note 1)
16 ** hm double height above ref. ellipsoid (geodetic, m)
17 ** xp,yp double coordinates of the pole (radians, Note 2)
18 ** sp double the TIO locator s' (radians, Note 2)
19 ** theta double Earth rotation angle (radians, Note 3)
20 **
21 ** Returned:
22 ** pv double[2][3] position/velocity vector (m, m/s, CIRS)
23 **
24 ** Notes:
25 **
26 ** 1) The terrestrial coordinates are with respect to the ERFA_WGS84
27 ** reference ellipsoid.
28 **
29 ** 2) xp and yp are the coordinates (in radians) of the Celestial
30 ** Intermediate Pole with respect to the International Terrestrial
31 ** Reference System (see IERS Conventions), measured along the
32 ** meridians 0 and 90 deg west respectively. sp is the TIO locator
33 ** s', in radians, which positions the Terrestrial Intermediate
34 ** Origin on the equator. For many applications, xp, yp and
35 ** (especially) sp can be set to zero.
36 **
37 ** 3) If theta is Greenwich apparent sidereal time instead of Earth
38 ** rotation angle, the result is with respect to the true equator
39 ** and equinox of date, i.e. with the x-axis at the equinox rather
40 ** than the celestial intermediate origin.
41 **
42 ** 4) The velocity units are meters per UT1 second, not per SI second.
43 ** This is unlikely to have any practical consequences in the modern
44 ** era.
45 **
46 ** 5) No validation is performed on the arguments. Error cases that
47 ** could lead to arithmetic exceptions are trapped by the eraGd2gc
48 ** function, and the result set to zeros.
49 **
50 ** References:
51 **
52 ** McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
53 ** IERS Technical Note No. 32, BKG (2004)
54 **
55 ** Urban, S. & Seidelmann, P. K. (eds), Explanatory Supplement to
56 ** the Astronomical Almanac, 3rd ed., University Science Books
57 ** (2013), Section 7.4.3.3.
58 **
59 ** Called:
60 ** eraGd2gc geodetic to geocentric transformation
61 ** eraPom00 polar motion matrix
62 ** eraTrxp product of transpose of r-matrix and p-vector
63 **
64 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
65 ** Derived, with permission, from the SOFA library. See notes at end of file.
66 */
67 {
68 /* Earth rotation rate in radians per UT1 second */
69  const double OM = 1.00273781191135448 * ERFA_D2PI / ERFA_DAYSEC;
70 
71  double xyzm[3], rpm[3][3], xyz[3], x, y, z, s, c;
72 
73 /* Geodetic to geocentric transformation (ERFA_WGS84). */
74  (void) eraGd2gc(1, elong, phi, hm, xyzm);
75 
76 /* Polar motion and TIO position. */
77  eraPom00(xp, yp, sp, rpm);
78  eraTrxp(rpm, xyzm, xyz);
79  x = xyz[0];
80  y = xyz[1];
81  z = xyz[2];
82 
83 /* Functions of ERA. */
84  s = sin(theta);
85  c = cos(theta);
86 
87 /* Position. */
88  pv[0][0] = c*x - s*y;
89  pv[0][1] = s*x + c*y;
90  pv[0][2] = z;
91 
92 /* Velocity. */
93  pv[1][0] = OM * ( -s*x - c*y );
94  pv[1][1] = OM * ( c*x - s*y );
95  pv[1][2] = 0.0;
96 
97 /* Finished. */
98 
99 }
100 /*----------------------------------------------------------------------
101 **
102 **
103 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
104 ** All rights reserved.
105 **
106 ** This library is derived, with permission, from the International
107 ** Astronomical Union's "Standards of Fundamental Astronomy" library,
108 ** available from http://www.iausofa.org.
109 **
110 ** The ERFA version is intended to retain identical functionality to
111 ** the SOFA library, but made distinct through different function and
112 ** file names, as set out in the SOFA license conditions. The SOFA
113 ** original has a role as a reference standard for the IAU and IERS,
114 ** and consequently redistribution is permitted only in its unaltered
115 ** state. The ERFA version is not subject to this restriction and
116 ** therefore can be included in distributions which do not support the
117 ** concept of "read only" software.
118 **
119 ** Although the intent is to replicate the SOFA API (other than
120 ** replacement of prefix names) and results (with the exception of
121 ** bugs; any that are discovered will be fixed), SOFA is not
122 ** responsible for any errors found in this version of the library.
123 **
124 ** If you wish to acknowledge the SOFA heritage, please acknowledge
125 ** that you are using a library derived from SOFA, rather than SOFA
126 ** itself.
127 **
128 **
129 ** TERMS AND CONDITIONS
130 **
131 ** Redistribution and use in source and binary forms, with or without
132 ** modification, are permitted provided that the following conditions
133 ** are met:
134 **
135 ** 1 Redistributions of source code must retain the above copyright
136 ** notice, this list of conditions and the following disclaimer.
137 **
138 ** 2 Redistributions in binary form must reproduce the above copyright
139 ** notice, this list of conditions and the following disclaimer in
140 ** the documentation and/or other materials provided with the
141 ** distribution.
142 **
143 ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
144 ** the International Astronomical Union nor the names of its
145 ** contributors may be used to endorse or promote products derived
146 ** from this software without specific prior written permission.
147 **
148 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
149 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
150 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
151 ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
152 ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
153 ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
154 ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
155 ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
156 ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
157 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
158 ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
159 ** POSSIBILITY OF SUCH DAMAGE.
160 **
161 */
int eraGd2gc(int n, double elong, double phi, double height, double xyz[3])
Definition: gd2gc.c:3
#define ERFA_DAYSEC
Definition: erfam.h:75
void eraPom00(double xp, double yp, double sp, double rpom[3][3])
Definition: pom00.c:3
#define ERFA_D2PI
Definition: erfam.h:48
void eraTrxp(double r[3][3], double p[3], double trp[3])
Definition: trxp.c:3
void eraPvtob(double elong, double phi, double hm, double xp, double yp, double sp, double theta, double pv[2][3])
Definition: pvtob.c:3