                                   SatTrack (V3.1) ---
                  A Realtime Satellite Tracking and Orbit Prediction
               Program for UNIX/Linux Platforms with X11 Color Graphics

                                   Manfred Bester

                                   August 17, 1995

     General description ===================

          SatTrack is a realtime satellite tracking and orbit prediction program
     with  an  X11  color  world  map tracking chart. It has been written in 'C'
     language  on  a  Sun/UNIX  workstation  and  provides  two  different  live
     displays,  for  single  or  multiple  satellites,  and  two different orbit
     prediction modes. Cursor controls used in the numerical live  displays  are
     compatible  with  the  VT100  standard,  which allows the program to be run
     basically from any terminal without the graphics display. If the program is
     run from an X Window terminal, the realtime graphics display can be started
     up. It will show the location of any number of  specified  satellites  like
     the Space Shuttle or the Russian Space Station Mir, featuring the circle of
     visibility for any selected spacecraft and for the primary and a number  of
     secondary  ground  stations.  Also  shown are the ground track for the next
     three orbits, the black-out  zones  for  communication  through  the  TDRSS
     network,  Mission  Elapsed  Time (MET), the terminator, spacecraft lighting
     conditions and other details. The world maps are provided in two  different
     styles  with  four  different  sizes each. Program SatTrack is particularly
     interesting for the upcoming Shuttle - Mir rendezvous missions.

          The present version of SatTrack (V3.1) can track  a  single  satellite
     and/or display multiple satellites for a single ground station. It can also
     control suitable ground station hardware, like antennas, optical telescopes
     and  communications  equipment with the proper Doppler corrections, and has
     an autotrack mode in which it can switch automatically between a number  of
     specified  satellites. For calibration purposes tracking of the Sun and the
     Moon are  also  provided.  In  the  orbit  prediction  mode  SatTrack  pre-
     calculates  passes  of  satellites  over  a  specified  ground station. The
     predictions can be run off either interactively or in a batch mode.

     The program uses the two-line Keplerian element (TLE) sets generated by the
     US  Space  Command  or  NASA to run either the SGP4 model for satellites in
     low-earth orbit or  a  simplified  model  for  deep-space  objects.  Future
     releases  (V3.5)  will have more features, like fast forward mode that will
     allow the user to view satellite motions at higher speed,  the  SDP4  model
     for  deep-space  objects,  multiple  ground  stations  and  second graphics
     display with a fish-eye sky view, and a  graphical  user  interface.  Other
     program  features will allow prediction of GPS coverage and precision (DOP)
     as a function of time.

     Applications ============

     Applications of this software package  range  from  visualizing  orbits  or
     monitoring  positions  of individual artificial satellites or any groups of
     satellites like the GPS system, to satellite system  monitoring  and  space
     shuttle  mission  control  objectives and mission planning, as well as full
     featured  and  automated  ground  station  control.   A  wide   number   of
     applications  becomes  feasible  with  the realtime hooks built into modern
     Unix systems like Solaris 2.3.

     System requirements ===================

          SatTrack  V3.1  has  been  successfully  compiled  on  the   following
     platforms:  Sun-3  or Sun-4 (SPARCstation IPC, 5 or 10) with SunOS 4.1.x or
     Solaris 2.x, HP Apollo 9000 Series 700, IBM RS-6000, SGI Indigo 2 with IRIX
     5.3, DEC Alpha with AXP/OSF, i386-Linux, i386-NetBSD, or i386-FreeBSD, with
     X11R5 and X11R6 and various window managers. Only basic X11 and X11 Toolkit
     functions have been used to allow the program to be ported easily. SatTrack
     requires about 5 MB of disk space and less than 1.5 MB  of  memory  at  run
     time.  With  operating  systems  like  Solaris  2.3  or VxWorks 5.1.1, true
     realtime performance can be achieved with SatTrack.

     How to obtain a copy ====================

          Current on-line information on SatTrack can be found on the World Wide
     Web page with the following URL:

                   http://ssl.berkeley.edu/isi_www/sattrack.html

          The distribution file 'sattrack.V3.1.1.tar.gz' can  be  obtained  from
     this  web  page  as  well and has to be uncompressed and unbundled with the
     commands tree. The README_MAKE file in the 'src' sub-directory gives  brief
     instructions to compile the source code. More documentation can be found in
     the 'doc' sub-directory.

     Copyright =========

     Copyright (c)  1992,  1993,  1994,  1995  by  Manfred  Bester.  All  Rights
     Reserved.

     Permission to  use  this  software  commercially  or  to  incorporate  this
     software  or  parts of it into commercial products may be obtained from the
     author, Dr. Manfred Bester, Bester Tracking  Systems,  P.O.  Box  9948,  CA
     94709, USA.