1 | #include "erfa.h"
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2 |
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3 | void eraC2tcio(double rc2i[3][3], double era, double rpom[3][3],
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4 | double rc2t[3][3])
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5 | /*
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6 | ** - - - - - - - - - -
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7 | ** e r a C 2 t c i o
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8 | ** - - - - - - - - - -
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9 | **
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10 | ** Assemble the celestial to terrestrial matrix from CIO-based
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11 | ** components (the celestial-to-intermediate matrix, the Earth Rotation
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12 | ** Angle and the polar motion matrix).
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13 | **
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14 | ** Given:
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15 | ** rc2i double[3][3] celestial-to-intermediate matrix
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16 | ** era double Earth rotation angle (radians)
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17 | ** rpom double[3][3] polar-motion matrix
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18 | **
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19 | ** Returned:
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20 | ** rc2t double[3][3] celestial-to-terrestrial matrix
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21 | **
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22 | ** Notes:
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23 | **
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24 | ** 1) This function constructs the rotation matrix that transforms
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25 | ** vectors in the celestial system into vectors in the terrestrial
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26 | ** system. It does so starting from precomputed components, namely
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27 | ** the matrix which rotates from celestial coordinates to the
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28 | ** intermediate frame, the Earth rotation angle and the polar motion
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29 | ** matrix. One use of the present function is when generating a
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30 | ** series of celestial-to-terrestrial matrices where only the Earth
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31 | ** Rotation Angle changes, avoiding the considerable overhead of
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32 | ** recomputing the precession-nutation more often than necessary to
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33 | ** achieve given accuracy objectives.
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34 | **
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35 | ** 2) The relationship between the arguments is as follows:
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36 | **
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37 | ** [TRS] = RPOM * R_3(ERA) * rc2i * [CRS]
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38 | **
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39 | ** = rc2t * [CRS]
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40 | **
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41 | ** where [CRS] is a vector in the Geocentric Celestial Reference
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42 | ** System and [TRS] is a vector in the International Terrestrial
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43 | ** Reference System (see IERS Conventions 2003).
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44 | **
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45 | ** Called:
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46 | ** eraCr copy r-matrix
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47 | ** eraRz rotate around Z-axis
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48 | ** eraRxr product of two r-matrices
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49 | **
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50 | ** Reference:
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51 | **
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52 | ** McCarthy, D. D., Petit, G. (eds.), 2004, IERS Conventions (2003),
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53 | ** IERS Technical Note No. 32, BKG
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54 | **
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55 | ** Copyright (C) 2013-2016, NumFOCUS Foundation.
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56 | ** Derived, with permission, from the SOFA library. See notes at end of file.
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57 | */
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58 | {
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59 | double r[3][3];
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60 |
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61 |
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62 | /* Construct the matrix. */
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63 | eraCr(rc2i, r);
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64 | eraRz(era, r);
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65 | eraRxr(rpom, r, rc2t);
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66 |
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67 | return;
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68 |
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69 | }
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70 | /*----------------------------------------------------------------------
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71 | **
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72 | **
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73 | ** Copyright (C) 2013-2016, NumFOCUS Foundation.
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74 | ** All rights reserved.
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75 | **
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76 | ** This library is derived, with permission, from the International
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77 | ** Astronomical Union's "Standards of Fundamental Astronomy" library,
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78 | ** available from http://www.iausofa.org.
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79 | **
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80 | ** The ERFA version is intended to retain identical functionality to
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81 | ** the SOFA library, but made distinct through different function and
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82 | ** file names, as set out in the SOFA license conditions. The SOFA
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83 | ** original has a role as a reference standard for the IAU and IERS,
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84 | ** and consequently redistribution is permitted only in its unaltered
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85 | ** state. The ERFA version is not subject to this restriction and
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86 | ** therefore can be included in distributions which do not support the
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87 | ** concept of "read only" software.
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88 | **
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89 | ** Although the intent is to replicate the SOFA API (other than
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90 | ** replacement of prefix names) and results (with the exception of
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91 | ** bugs; any that are discovered will be fixed), SOFA is not
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92 | ** responsible for any errors found in this version of the library.
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93 | **
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94 | ** If you wish to acknowledge the SOFA heritage, please acknowledge
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95 | ** that you are using a library derived from SOFA, rather than SOFA
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96 | ** itself.
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97 | **
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98 | **
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99 | ** TERMS AND CONDITIONS
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100 | **
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101 | ** Redistribution and use in source and binary forms, with or without
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102 | ** modification, are permitted provided that the following conditions
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103 | ** are met:
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104 | **
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105 | ** 1 Redistributions of source code must retain the above copyright
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106 | ** notice, this list of conditions and the following disclaimer.
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107 | **
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108 | ** 2 Redistributions in binary form must reproduce the above copyright
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109 | ** notice, this list of conditions and the following disclaimer in
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110 | ** the documentation and/or other materials provided with the
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111 | ** distribution.
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112 | **
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113 | ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
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114 | ** the International Astronomical Union nor the names of its
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115 | ** contributors may be used to endorse or promote products derived
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116 | ** from this software without specific prior written permission.
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117 | **
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118 | ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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119 | ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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120 | ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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121 | ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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122 | ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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123 | ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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124 | ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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125 | ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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126 | ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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127 | ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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128 | ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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129 | ** POSSIBILITY OF SUCH DAMAGE.
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130 | **
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131 | */
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