                                   TRACKER v1.10
                                   -------------
                                   1999, May  15

Tracker is a program designed to create BMP maps of the images taken by
the NOAA polar orbiting satellites. Those maps show both country borders and
sea/surface boundaries. There are actually three different programs:

1. MAP.EXE + SMALL.LIN : Taken from a world map database, the MAP.EXE produces
two files: MAP.BMP and MAP.CFG. Those files have to be created before using the
program for the first time. They should contain a map of your region. For
example, in order to create maps for europe run:
        MAP SMALL.LIN 3000 2000 -20 50 20 80
Look at the resulting MAP.BMP and make sure it covers all the regions you
find in your NOAA images. The scale of the map created should be more or
less the same as the images taken by the NOAA satellites. The map
has to be created only once.

2. ORBIT.EXE : This is the program processing the two-line elements and
producing highly accurate satellite location information for every half second
during the satellite's pass. This is essentially the TRAKSTAR program written
by Dr TS Kelso slightly changed to simplify usage in that case. Using it is
quite simple; just run:
        ORBIT NOAA14.OUT
or any other file name into which you want the satellite location information
to be written. The program will ask you for the name of a TLE 2-line elements
file. A sample WEATHER.TLE file is given but be sure to have an updated file!
Then mark the satellite you are interested in (only one allowed). Then the
start and stop UTC time. The program currently cannot handle tracks of longer
than 25 minutes so be careful. That's it. The resulting file (NOAA14.OUT in the
example above) contains latitude, longitude and altitude information for every
half second in the time period you specified.

3. TRACKER.EXE - After computing the satellite location file in the previous
section, run the TRACKER program with that file:
        TRACKER NOAA14.OUT
This program will combine the location file with the map file for your area. If
everything goes well, it will create a file called OUTPUT.BMP which contains a
map of the NOAA pass you specified. That BMP should be combined with the NOAA
image by any of your favorite image processing programs.

Notes:
------

1. The width of the ground map produced is 1040 pixels and you must configure
your satellite decoder to produce pictures of the same width.

2. The ground map produced has minute markers and borders that should be
aligned with the NOAA picture.

3. The MAP.BMP can be replaced with a sea/surface mask similiar to the ones
used with METEOSAT. I could not get hold of such maps but using them could
produce nice results and better colouring of the NOAA pictures.

4. The maps are not always 100% accurate. The algorithm for the satellite
location is very accurate. However I have used a simple method of finding the
spot on earth the satellite is looking on at any point in time and not the more
accurate method recommended by NOAA. You might want to have a look at the NOAA
KLM user's guide at: http://www2.ncdc.noaa.gov/docs/klm/. It contains detailed
information regarding the NOAA satellites and has a section describing the
earth locating algorithm. I've found that the error at NOAA-14 images is
usually not more than 2 pixels.

5. Aligning the images and maps has to be done manually using a separate
image processing program. Combining that functionality with the TRACKER
can simplify its usage.

6. All the sources are included and you are encouraged to continue
improving the program.

Known bugs:
-----------

I am not sure how it would behave at around 180E longitude.
The maps are somewhat pixelized; changing the resolution
of MAP.BMP might help.

The ORBIT program will not run on fast computers (somewhere
around 300Mhz and above). The only way to fix it
is running a TSR program that slows the computer in dos mode.
You will probably find such programs in http://WWW.SIMTEL.NET .
In the next version I'll try to add it to the release.

Credits:
--------

The program is based on the sources released by Dr TS Kelso. The sources
allow the accurate satellite location calculations by using 2-line elements. My
task would have been almost impossible without his sources.

Version History:
----------------

1.1: Fixed bug in TRACKER.EXE with longitudes in the range
        100E-360E (=100E-0E)

1.0: First version

Copyright:
----------

TRACKER v1.10
Copyright (C) 1999

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

4Z5BS
4z5bs@walla.co.il
