USAT --- A Unix compatible satellite tracking package Version 1.0 This is a package of programs and subroutines for tracking satellites. The routines that produce the geocentric satellite positions are C versions of the NORAD satellite ephemeris programs described in doc/spacetrk.tex. These routines were converted to C and put under the Revision Control System (RCS). All these routines generate nearly identical geocentric coordinates as given in the examples in doc/spacetrk.tex with the exception of sdp8. A careful investigation of the sdp8 routines has not found any reason for the discrepancies. The routines that convert the geocentric satellite positions to topocentric positions are a modified version of Stephen L. Moshier's Astronomical Almanac package V5.1 (see the READMEs in the almanac directory). The Makefile in this directory will make all necessary routines in the subdirectories. Currently, any changes made with this Makefile should also be made to the Makefiles in the subdirectories (to be corrected in a future version of this software). The Makefile is designed to be used with gmake. The following executables are made: almanac Essentially Stephen L. Moshier's almanac program. Generates the position of the Sun, Moon, planets, etc for a given date along with rises, sets, transits, and many other bits of information. bsat An interactive satellite ephemeris generator. Will generate coordinates for all the satellites in a two line element set file between given times at a given interval. isat Another interactive satellite ephemeris generator. Will only do a ephemeris of the first satellite in a two line element set file. Basically used to test the various NORAD satellite ephemeris programs. plotgen Generates a GNUPLOT command file for plotting the results of the sunsat program. sawsat An interactive program that searches a two line element set file for satellites that approach within a given radius of a given ra and dec, for a given time period. Can be used to identify satellites or to see if any satellites enter a given field of interest during a specific time. sunsat A batch program used to find satellites that approach within 1.5 degrees of the Sun and to generate 1 second ephemerides of those approaches. In addition, the get-tles C-shell script is used to update the two line element set files and to run sunsat on a subset of these files. In order to run any of the programs, the local site information must be contained in either a ~/.site.ini file or a ./.site.ini file. The .site.ini file here is for Sunspot, New Mexico, USA. As the parallax corrections used to generate the topocentric satellite positions are often tens of degrees, a accurate .site.ini file is a must. These routines were compiled by gcc 2.3.3 under SUNOS 4.1.2. I would appreciate any information regarding compilation using different compilers and different operating systems. In addition, I would appreciate any information concerning the accuracy of any predictions (I will boldly state here that with limited use, the accuracy appears to be better than .1 degree). Any other comments or suggestions are welcome. Selected file/directory descriptions are given below: .site.ini The site description file. Filelist A list and brief description of files under RCS. RCS The RCS directory. README This file. almanac The directory containing the modified astronomical almanac routines originally written by Stephen L. Moshier. doc Miscellaneous documentation. for Fortran listings of the NORAD satellite ephemeris code. h Header files. lib Compiled library files. tle Contains two line element set files. Craig Gullixson 18 May 1993. Craig A, Gullixson Sr. Research Associate National Solar Observatory/ Sacramento Peak P.O. Box 62 Sunspot, New Mexico 88340-0062 (505) 434-7088 craig@sunspot.noao.edu
