source: trunk/MagicSoft/slalib/pvobs.c@ 9223

Last change on this file since 9223 was 731, checked in by tbretz, 24 years ago
*** empty log message ***
  • Property svn:executable set to *
File size: 1.2 KB
Line 
1#include "slalib.h"
2#include "slamac.h"
3void slaPvobs ( double p, double h, double stl, double pv[6] )
4/*
5** - - - - - - - - -
6** s l a P v o b s
7** - - - - - - - - -
8**
9** Position and velocity of an observing station.
10**
11** (double precision)
12**
13** Given:
14** p double latitude (geodetic, radians)
15** h double height above reference spheroid (geodetic, metres)
16** stl double local apparent sidereal time (radians)
17**
18** Returned:
19** pv double[6] position/velocity 6-vector (au, au/s, true
20** equator and equinox of date)
21**
22** IAU 1976 constants are used.
23**
24** Called: slaGeoc
25**
26** Last revision: 14 November 1994
27**
28** Copyright P.T.Wallace. All rights reserved.
29*/
30
31#define SR 7.292115855306589e-5 /* Mean sidereal rate (at J2000)
32 in radians per (UT1) second */
33
34{
35 double r, z, s, c, v;
36
37/* Geodetic to geocentric conversion */
38 slaGeoc ( p, h, &r, &z );
39
40/* Functions of ST */
41 s = sin ( stl );
42 c = cos ( stl );
43
44/* Speed */
45 v = SR * r;
46
47/* Position */
48 pv[0] = r * c;
49 pv[1] = r * s;
50 pv[2] = z;
51
52/* Velocity */
53 pv[3] = - v * s;
54 pv[4] = v * c;
55 pv[5] = 0.0;
56}
Note: See TracBrowser for help on using the repository browser.