Homemade GPS TLE's

Tue, 19 Oct 99 10:32:00 NZST

>>I have recently written software to create GPS TLE's directly
>>from a GPS receiver.

>       HEY!  This sounds interesting!

>       Does it use the NMEA output or something else?  If NMEA,
>then it would work with MOST common GPS units around today.

>       Nice job!

>       Earl
>       Earl Needham, KD5XB    mailto:KD5XB@AMSAT.ORG

Hello Earl,

To answer your question, I have copied (see below) a bit from my
"readme.txt" file. Nice of you to show an interest, I wondered
if anyone would want to play with the programs.

Many thanks to Harro (Harro.Zimmer@t-online.de) who advised me that :-

The PRN for the GPS  1999-055A is  11, the SVN is  46.

That is the only bit of information I needed to finish off the
project, I can now post it on the NET, just give me a few days
to gather my strength so I can push the archive up over the
equator. I will post the NASA URL here when it is ready for
interested people to have a look at. The program is freeware for
hobbyists to tinker with.

The following is a quote from my "readme" file.
         Making your own GPS NAVSTAR TLE file.

The group of utilities in this archive, allow a user to produce
a GPS NAVSTAR TLE (Two Line Element) file from a number of
optional sources. The TLE produced when used on satellite
tracking software can give the position of any of the GPS
satellites to an accuracy better than 6 minutes of arc (1/10th
degree).  This is useful for many amateur hobbies to do with
satellite tracking, tracking with amateur optical telescopes,
satellite rise and set (antenna directionality) and just a
learning exercise to do with almanacs, Keplerian elements and
SGP data algorithms.

The motive for making this software was as a winter hobby, to
learn about GPS and because I have a permanent GPS receiver
(used for R&D) attached to my PC network. I also liked the
concept of clicking a mouse to get my own orbital TLE's directly
off the satellites overhead.  Maybe its useful for you too,
especially if you are at a remote site and do not have access to
the Internet and USSPACECOMS TLE's.

Which utilities you use depend on how you are able to produce
the almanac file. There are four options.

1. Your GPS receiver can output the Almanac in YUMA format.

2. Your GPS receiver can output the Almanac in NMEA format.

3. You have a Motorola Oncore receiver (and perhaps older Motorola
receiver) using the Motorola binary format.

4. You have access to the Internet.


The 3 exe programs are all compiled as 16 bit DOS applications -
should also run fine under the various Windows platforms.

Regards Geoff,

 Latitude:  43.5197 degrees SOUTH
Longitude: 172.7022 degrees EAST

Christchurch, New Zealand, South Pacific.

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