[Laser] Telescope & GPS interfac

[Chuck Hast]

On 7/18/07, Terry Morris W5TDM <w5tdm at hotmail.com> wrote:
> Hello Chuck & group,
>
> Here is what I found out so far:
>
> Garmin GPS has serial port @ 4800 Baud and will output the following data
> types:
> GARMIN, NEMA 0183 V 2.00, RTCM/NEMA, RTCM. Baud rate doesn't appear to be
> changable.
>
> Celestron Telescope has a serial port @ 9600 Baud ( first problem). The
> telescope "Get Position Command" is looking for position data in either
> RA/DEC or AZM-ALT coordinates. (second problem).
>
> So it is looking like a laptop and software may be one answer. The other
> answer is the Celestron GPS Module @ $199.00 is looking a lot cheaper all
> the time.
>
> I know there are a lot of people on the list with a lot of knowledge on GPS
> interfacing, does anyone see something I am missing.
>
I think the term is "Protocol Converter"... You probably want something that
can take the proprietary GARMIN protocol (it I believe has a bit better resol-
ution than the NMEA protocol. RTCM is used for differential GPS and is wh-
at the differential station sends to the differential receiver to
correct the GPS
data for propagation and other errors. Your GARMIN connected to a differen-
tial receiver with the frequence for the differential transmitter out on Egmont
key (local differential base station in the Tampa Bay area) could supply you
with some pretty accurate position info... If you have a differential base sta-
tion in your area you can use that, and it will give you better accuracy, but
you need the data to have enough resolution. NMEA does DDMM.MMM or
it does DD.dddddd I believe, but need to check it. I do not know how much
accuracy you need. You will also need to know what the protocol looks like
that you feed to scope, and then get someone to code up a converter...




-- 
Chuck Hast  -- KP4DJT --
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."