[aprssig] APRS geographic coordinates

[Curt, WE7U]

On Mon, 24 Jul 2006, Bruce Prior wrote:

> I notice that some raw APRS packets include latitude and longitude, but
> others do not.  Is there a compressed system of geographic coordinates used
> by APRS?  If so, how can I translate it into one of the standard coordinate
> systems?

There are two that are currently used for APRS:  One is called Mic-E
protocol, the other is called Base-91 compression.  They can both be
found in the APRS Spec.

You may have seen Base-91 compressed packets from me as I'm south of
you by a bit (WE7U-12 & WE7U-3).

Many mobile stations are running Mic-E compression, for instance the
TH-D7A and TM-D700A Kenwood radios, and many of the TinyTrak's.

The easiest way to translate the coordinates would be to run a
client program that does this for you, then read the lat/long
coordinates from there.  Translating them by hand is a royal pain.

--
Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer
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