[aprssig] Item-in-msg (was solar impulse tracking)

Andrew Elwell andrew.elwell at gmail.com
Mon May 6 20:12:49 CDT 2013


Hi Bob et al,

> NOTE!  We could do this centrally from one location if IGATE clients
> implemented the ITEM-IN-MSG protocol.  This next phase of APRS has been
> proposed in APRS1.2 for over 5 years now.  But I am not sure if any clients
> have implemented it.  We need to get moving on this.  ITEM-in-MSG is
> fundamental to a number of APRS initiatives to improve the ability to convey
> info to others in real time.

I've just looked at the spec for both item-in-msg.txt and msg-obj.txt
and I have a few questions:

is the item-in-msg *always* directed to an individual callsign? ie,
for the solar impulse tracking there's no way to make a broadcast
style announcement of (location of plane + radius 100km)?

Secondly the msg-obj seems to be tied to the position of the sender -
again, you'd have to fake your position to be able to do the solar
impulse stuff above.

Finally the mention of the KILL, QRZ and [Generic] OBJECT servers in
msg-obj -- are they connected via aprs-is to provide global coverage
or are they expected to be RF only (wondering how you'd prevent faking
of a KILL to remove an object, or how a KILL server would communicate
with the PLANE_OBJECT server to say that solar impulse had been
removed as its now completed its journey?)

Andrew


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