| 1 | /*
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| 2 | *+
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| 3 | * Name:
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| 4 | * palPvobs
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| 5 |
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| 6 | * Purpose:
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| 7 | * Position and velocity of an observing station.
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| 8 |
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| 9 | * Language:
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| 10 | * Starlink ANSI C
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| 11 |
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| 12 | * Type of Module:
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| 13 | * Library routine
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| 14 |
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| 15 | * Invocation:
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| 16 | * palPvobs( double p, double h, double stl, double pv[6] )
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| 17 |
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| 18 | * Arguments:
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| 19 | * p = double (Given)
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| 20 | * Latitude (geodetic, radians).
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| 21 | * h = double (Given)
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| 22 | * Height above reference spheroid (geodetic, metres).
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| 23 | * stl = double (Given)
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| 24 | * Local apparent sidereal time (radians).
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| 25 | * pv = double[ 6 ] (Returned)
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| 26 | * position/velocity 6-vector (AU, AU/s, true equator
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| 27 | * and equinox of date).
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| 28 |
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| 29 | * Description:
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| 30 | * Returns the position and velocity of an observing station.
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| 31 |
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| 32 | * Notes:
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| 33 | * - The WGS84 reference ellipsoid is used.
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| 34 |
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| 35 | * Authors:
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| 36 | * PTW: Pat Wallace (STFC)
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| 37 | * DSB: David Berry (JAC, Hawaii)
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| 38 | * {enter_new_authors_here}
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| 39 |
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| 40 | * History:
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| 41 | * 2012-02-16 (DSB):
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| 42 | * Initial version.
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| 43 | * Adapted with permission from the Fortran SLALIB library.
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| 44 | * {enter_further_changes_here}
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| 45 |
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| 46 | * Copyright:
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| 47 | * Copyright (C) 1995 Rutherford Appleton Laboratory
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| 48 | * Copyright (C) 2012 Science and Technology Facilities Council.
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| 49 | * All Rights Reserved.
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| 50 |
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| 51 | * Licence:
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| 52 | * This program is free software: you can redistribute it and/or
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| 53 | * modify it under the terms of the GNU Lesser General Public
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| 54 | * License as published by the Free Software Foundation, either
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| 55 | * version 3 of the License, or (at your option) any later
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| 56 | * version.
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| 57 | *
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| 58 | * This program is distributed in the hope that it will be useful,
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| 59 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 60 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 61 | * GNU Lesser General Public License for more details.
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| 62 | *
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| 63 | * You should have received a copy of the GNU Lesser General
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| 64 | * License along with this program. If not, see
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| 65 | * <http://www.gnu.org/licenses/>.
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| 66 |
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| 67 | * Bugs:
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| 68 | * {note_any_bugs_here}
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| 69 | *-
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| 70 | */
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| 71 |
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| 72 | #include "pal.h"
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| 73 | #include "palmac.h"
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| 74 | #include "palmac.h"
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| 75 | #include "pal1sofa.h"
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| 76 |
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| 77 | void palPvobs( double p, double h, double stl, double pv[6] ){
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| 78 |
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| 79 | /* Local Variables: */
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| 80 | double xyz[3], z, r, s, c, v;
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| 81 |
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| 82 | /* Geodetic to geocentric conversion (WGS84 reference ellipsoid). */
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| 83 | eraGd2gc( ERFA_WGS84, 0.0, p, h, xyz );
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| 84 |
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| 85 | /* Convert from metres to AU */
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| 86 | r = xyz[ 0 ]/ERFA_DAU;
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| 87 | z = xyz[ 2 ]/ERFA_DAU;
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| 88 |
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| 89 | /* Functions of ST. */
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| 90 | s = sin( stl );
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| 91 | c = cos( stl );
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| 92 |
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| 93 | /* Speed. */
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| 94 | v = PAL__SR*r;
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| 95 |
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| 96 | /* Position. */
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| 97 | pv[ 0 ] = r*c;
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| 98 | pv[ 1 ] = r*s;
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| 99 | pv[ 2 ] = z;
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| 100 |
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| 101 | /* Velocity. */
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| 102 | pv[ 3 ] = -v*s;
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| 103 | pv[ 4 ] = v*c;
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| 104 | pv[ 5 ] = 0.0;
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| 105 |
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| 106 | }
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| 107 |
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| 108 |
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