[OZAPRS] A Remote GPS.

[Darryl Smith]

Can anyone else help Noel? 

This is outside my area of expertese well and truly. I really have no
idea where to go, other than build a PIC based TNC up.

Darryl

---------
Darryl Smith, VK2TDS   POBox 169 Ingleburn NSW 2565 Australia
Mobile Number 0412 929 634 [+61 4 12 929 634 International] 
Darryl at radio-active.net.au | www.radio-active.net.au  

-----Original Message-----
From: ozaprs-admin at marconi.ics.mq.edu.au
[mailto:ozaprs-admin at marconi.ics.mq.edu.au] On Behalf Of Noel Rowe
Sent: Tuesday, 19 November 2002 7:33 AM
To: ozaprs at marconi.ics.mq.edu.au
Subject: Re: [OZAPRS] A Remote GPS.


Darryl,

>Using the com-port loopback method it sounds like what you ware wanting

>is a small PIC processor to convert the MIC-E RS-232 string into a 
>$GPRMC type GPS string? Is that correct.

Yes, that could work, as long as we can "get at" the data string as its
not RS232 unless we make it so.  See story below.

>Of course you may be able to take some virtual serial port software and

>modify it with some processing...

Thats possible also.  The virtual softwareI am using  is the one
provided by the MixW team, and it can be found at -
http://mixw.net/related.htm  in the section about TNC emulation.


Problem :  The TinyTrak sends a mic-e (compressed) beacon, and the other
(non APRS) program we need to run needs an RS232 or virtual $GPRMC NMEA
sentence.

So we need to extract the beacon after demodulating (if thats the right
word) the audio received by the radio on shore, and processed in the PC
by the AGW packet engine software using the sound card as the interface.
Then in either external hardware or internal software we need to
recreate the $GPRMC NMEA sentence to as it was prior to the TinyTrak
compressing it.  The program we want to run expects the GPS to be on a
serial port, and we need to simulate that.

The following almost does it :-

http://www.kh-gps.de/micenmea.htm

But it needs the mic-e signal in to be as if it was output by a TNC2 in
KISS mode.  We dont use a TNC, but the same signal must lurk within
AGW-pe somewhere, as other packet programs can run as if in KISS mode
when using AGW.

I have the virtual serial port software from the mixW site running fine
(needs WinXP) and the last mods made to UI-View (V1.84) allows you to
input a GPS at a serial port for running say a laptop with UI-View, and
output via another (real or virtual) port,  to say a nav program
shareing the GPS data.

Cheers, Noel, ZL3GR.


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