[aprssig] The best resolution of position from APRS

Scott Miller scott at opentrac.org
Tue Jan 3 23:09:40 EST 2006

> Having you put into your trackers  the ability to 
> generate obsolete and unsupported compressed 
> objects is just putting a time-bomb into the APRS
> system that will just guarantee that 85% of all mobile 
> operators won't see them if an open-tracaker
> happens to unknowingly use it.

They don't have the ability to GENERATE any objects or items.  Not yet,
anyway.  I'd like to change that, but Garmin didn't make it easy - no way to
poll for waypoints without causing a message and/or beep every time, no way
to transfer single waypoints out of the unit, no way to initiate a transfer
from the receiver...

And even if I do get to that point, I may not use compressed format.  But
others have made good points about its utility in SAR (my target application
from the start), and I don't think the new format has caught on sufficiently

People still choose to use the compressed object format, so I'll support it
on the RX side at the very least.  If someone wants to use Xastir for SAR in
a closed environment, they should be able to use all of its capabilities.

> resolution down to a foot.  ALSO and of equal
> importance it included the DATUM as well.  SInce
> in my opinion, sending that kind of precision is 
> useless if the datum is not included.

I still disagree with that move.  I say make the datum part of the spec -
fix it at WGS84.  Much easier to have the GPS receiver take care of that,
since it knows the math already.  If that had been part of the spec from the
start, do you think Kenwood would have found space in their firmware for
datum conversion?  I really doubt it.


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