[aprssig] The best resolution of position from APRS

Curt, WE7U archer at eskimo.com
Thu Jan 5 12:25:47 EST 2006

On Wed, 4 Jan 2006, Scott Miller wrote:

> The Kenwoods don't delete killed objects and items either.  Are we striking
> that from the spec next?  After all, it's bound to create confusion when
> Kenwood users start seeing objects that aren't there to everyone else.

It's not just that:

Imagine using the !DAO! thing, sending out a higher resolution
object from SAR base.  Imagine that the objects is placed on one
side of a raging whitewater creek or river, impassable.

A D700A user sees the object on the LCD or on his attached GPS,
figures out a route to it on his detailed map, and drives to the
wrong side of the river due to the D700A not understanding the !DAO!
extension.  He's only got about 60' resolution with MIC-E or
standard APRS packets.  This could be life-threatening due to the
delays it could cause!

If it was originally sent out as a compressed object and he couldn't
see it on his Kenwood but had voice or APRS messaging instructions
to go to that spot, he would have checked back with base for

Ok, that's a bit contrived, as if it was a life-or-death sort of
thing we wouldn't be using APRS objects and/or messaging but would
be using voice comms.  There could be times though where voice comms
fail and we might have to resort to backup methods of
communications, so it _could_ happen somewhat as described...

As one person already mentioned, SAR _is_ and emergency situation,
every single time we're called out, and we want to be able to use
every method at our disposal to find and/or rescue the person will
all expediency, plus of course keep our rescuers safe while doing

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