[aprssig] The best resolution of position from APRS

Tapio Sokura oh2kku at iki.fi
Wed Jan 4 19:51:45 EST 2006


Robert Bruninga wrote:
> 100% compatible with everything on the air.  And to 
> assure 100% on-air compatibiilty to all users, is why
> the compressed/object/item format was depricated
> since at the time it was not implemented in most code
> and was broken in others.

I've been thinking about this before, but now it came to my mind again. 
We should really have some kind of "torture test" for APRS 
protocol/applications. A start would be some kind of collection of 
known-valid APRS-packets demonstrating as many combinations as 
realistically possible. Also for those rarely used features. All in a 
simple text file or something that could easily be fed to APRS parsers 
and associated commentary on what is in each packet and how it should 
display/decode.

Why? Because APRS is a very complicated, and dare I say convoluted, 
protocol and I suspect no program really supports it fully (ok, maybe 
dosaprs does). With a known reference frame it would be easy to test 
applications that they at least decode APRS properly. Encoding should be 
tested as well, some way. As the history demonstrates, there are several 
more or less broken implementations of APRS out there, espcially on 
those parts that handle things that a human "can't see" like mic-e and 
compressed positions.

   Tapio




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