1 /**************************************************************************
2 * constants.h -- various constant definitions
4 * Written by Curtis Olson, started July 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 * (Log is kept at end of this file)
24 **************************************************************************/
34 /* This should be defined in the toplevel make.inc */
36 #define VERSION "\"not defined\""
40 /* Make sure PI is defined in its various forms */
44 # define FG_PI 3.14159265358979323846 /* pi */
48 # define FG_PI_2 M_PI_2
50 # define FG_PI_2 1.57079632679489661923 /* pi/2 */
53 #define FG_2PI (FG_PI + FG_PI) /* 2*pi */
56 /* Radius of Earth in kilometers at the equator. Another source had
57 * 6378.165 but this is probably close enough */
58 #define EARTH_RAD 6378.155
61 /* Earth parameters for WGS 84, taken from LaRCsim/ls_constants.h */
63 /* Value of earth radius from [8] */
64 #define EQUATORIAL_RADIUS_FT 20925650. /* ft */
65 #define EQUATORIAL_RADIUS_KM 6378138.12 /* meter */
67 #define RESQ_FT 437882827922500. /* ft */
68 #define RESQ_KM 40680645877797.1344 /* meter */
70 /* Value of earth flattening parameter from ref [8]
74 * EPS = sqrt(1-(1-f)^2)
77 #define FP 0.003352813178
79 #define EPS 0.081819221
80 #define INVG 0.031080997
83 /* Time Related Parameters */
85 #define MJD0 2415020.0
86 #define J2000 (2451545.0 - MJD0)
87 #define SIDRATE .9972695677
92 /* Degrees to Radians */
93 #define DEG_TO_RAD 0.017453292 /* deg*pi/180 = rad */
95 /* Radians to Degrees */
96 #define RAD_TO_DEG 57.29577951 /* rad*180/pi = deg */
98 /* Arc seconds to radians */ /* (arcsec*pi)/(3600*180) = rad */
99 #define ARCSEC_TO_RAD 4.84813681109535993589e-06
101 /* Radians to arc seconds */ /* (rad*3600*180)/pi = arcsec */
102 #define RAD_TO_ARCSEC 206264.806247096355156
105 #define FEET_TO_METER 0.3048
108 #define METER_TO_FEET 3.28083989501312335958
111 /* For divide by zero avoidance, this will be close enough to zero */
112 #define EPSILON 0.000001
115 /* Timing constants for Flight Model updates */
116 #define DEFAULT_TIMER_HZ 20
117 #define DEFAULT_MULTILOOP 6
118 #define DEFAULT_MODEL_HZ (DEFAULT_TIMER_HZ * DEFAULT_MULTILOOP)
121 #endif /* CONSTANTS_H */
125 /* Revision 1.10 1997/09/13 01:59:45 curt
126 /* Mostly working on stars and generating sidereal time for accurate star
129 * Revision 1.9 1997/08/22 21:34:32 curt
130 * Doing a bit of reorganizing and house cleaning.
132 * Revision 1.8 1997/07/31 22:52:22 curt
133 * Working on redoing internal coordinate systems & scenery transformations.
135 * Revision 1.7 1997/07/23 21:52:10 curt
136 * Put comments around the text after an #endif for increased portability.
138 * Revision 1.6 1997/07/21 14:45:01 curt
141 * Revision 1.5 1997/07/19 23:04:46 curt
142 * Added an initial weather section.
144 * Revision 1.4 1997/07/19 22:37:03 curt
145 * Added various PI definitions.
147 * Revision 1.3 1997/07/14 16:26:03 curt
148 * Testing/playing -- placed objects randomly across the entire terrain.
150 * Revision 1.2 1997/07/08 18:20:11 curt
151 * Working on establishing a hard ground.
153 * Revision 1.1 1997/07/07 21:02:36 curt