### usat-1.01a README file

    	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