[Xastir-dev] Re: [Xastir] Is traffic encryption possible?

[Tapio Sokura]

Tom Russo wrote on the xastir list:
> On Mon, Nov 12, 2007 at 01:39:12AM +0200, we recorded a bogon-computron collision of the <oh2kku at iki.fi> flavor, containing:
> 
>>If I remember correctly, Xastir should also
>>support the !DAO! format that provides one additional minute decimal digit
>>to the basic resolution, yielding a resolution of at least 2 meters
>>http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir

> No.  This keeps getting stated on APRSSIG as if it were fact, but it is not
> true.  Xastir does NOT implement !DAO!.  Nobody has ever coded it up.

I played around with the "spec" and xastir code and produced a patch 
against current CVS that implements receiving of !DAO!, both "human 
readable" and base91 variants. It's not perfect, but "works for me".

IMO the biggest additional tweak the patch needs is changing of the 
white error box dimensions. I didn't do it because the calling function 
overwrites p_station->lat/lon_precision and I didn't feel comfortable 
playing around with the calling function. But the patch does change the 
return value of extract_position() to 2 or 3 when added precision is 
available (3 or 4 decimals of minute respectively).

Also different datums are accepted in input, but ignored in processing. 
The datum byte is returned by decode_dao(), but currently unused.

http://www.oh2kku.ham.fi/aprs/misc/xastir-db-dao-20071115-oh2kku.patch

   Tapio