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[aprssig] Object Classification (FINAL WORD)

Andre aprs at pe1rdw.demon.nl
Tue Oct 18 15:09:34 UTC 2011


Op 18-10-2011 15:56, Bob Bruninga schreef:
> Here is SUMARY on Objects, Staitons, and Tactical calls usage in APRS:
>
> I have been very busy, so may not be following the thread and am leaving in
> 2 hours for 3 days travel.  But I will clarify exactly how APRS works with
> respect to objects and stations and tactical calls.
>
> 1) Objects, Tactical calls and Stations all have one objective.  That is, to
> send a SYMBOL and a POSITION and some comment data into the tactical
> situational awareness of everyone involved.
>
> 2) All of these "things" no matter how they are transmitted should be
> treated EXACTLY THE SAME once they are received.  They are "things" with
> POSITION on an APRS map or data base.
>
> 3) The EQUALITY of these "things" was fundamental to the APRS design.
> Because  the whole idea of an APRS map was to maintain a TACTICAL
> SITUATIONAL AWARENESS in a distributed system architecture.  Meaning...
>
> 4) ANYONE with new, more relevant or updated information about ANYTHING on
> the APRS map is allowed to update that "things" position, text, or comment,
> and that UPDATE is propagated to all stations, and all maps, and so everyone
> sees the same tactical picture updated in real time from live human
> operators "maintaining the tactical picture".. And the person that did the
> last update is KNOWN and CAPTURED.
>
> 5) THIS MEANS, an OBJECT, a STATION, or a TACTICAL CALLSIGN are IDENTICL
> with respect to updates.  If the mobile WB4APR-9 is showing in the middle of
> the bridge, because that was the last posit before my APRS device died, and
> yet it was being used in an event and I am now elsewhere, I should be able
> to go to ANY APRS station and update an OBEJCT of the same name WB4APR-9 and
> that OBJECT should completely replace all instances of WB4APR-9 (the
> station) on all maps and everywhere.  The idea is HUMANS maintaining the
> *correct* tactical picture, not dependent on the garbage and errors
> generated by devices, and a means so that the HUMANS can clean it up on the
> air.
>
> This on-air editing is FUNDAMENTAL to APRS.
>
> ***   The Problem is that UIVIEW DID IT WRONG ***  Uivew treats objects and
> stations separately and thus crippled this fundamental aspect of APRS.  And
> since 85% of APRS operators used UIview at one time or another, they
> accepted this erroneous implementation as right.  But it is wrong.
>
> SO, back to the difference between OBJECTS, STATIONS and TACTICAL CALLS.
> THEY ARE ALL THE SAME.  They simply use different formats to transmit the
> same POSITION data.
>
> STATION FORMAT: lets the TNC MYCALL be the "thing's name".  This has the
> advantage  that it saves 11 bytes, because the MYCALL is always in the
> packet anyway.  It has the disadvantage that the "things" name can only be 6
> alphanumericas and an SSID.
>
> OBJECT FORMAT:  lets the NAME be up to 9 alphanumeric letters, and allows
> for a time stamp.  Receiving stations are supposed to capture these to the
> same POSITION list as everything else (replacing anything with the same
> name, just like any other same-named thing).  Receiving systems are also
> supposed to capture WHO sent the object as well.  Display of that is up to
> the client.  ITEMS are the same as OBJECTS too
>
> TACTICAL-CALLS FORMAT: is simply taking the STATION FORMAT and using a
> TACTICAL name that will fit in the limitations of MYCALL field.  But to be
> legal AX.25, this packet format needs to include the FCC callsign of the
> sending station, and this is usually done by adding the TEXT of "de MYCALL"
> within the text of the position report at the end.
>
> The ONE ADVANTAGE OF USING THE STATION FORMAT, is that only the STATION
> FORMAT can be forced through the APRS-IS and through an IGATE back to RF as
> a courtesy position report WHEN-AND-ONLY-WHEN that station is involved in
> 2-way messaging.
>
> So, in the case of Lynn's Satellite Objects, it is a perfect marriage, of
> using a TACTICAL CALL of the name of the satellite so that his global server
> system gets this ADVANTAGE of the courtesy posit that can go back through
> the IGate to someone requesting info on said satellite.  Hence, the logical
> way to identify his program as the SOURCE of these TACTICAL CALLS is by
> doing what we have always done for tactical calls, that is PUT "de KJ4ERJ"
> at the end of the packet.
>
> Hope that clarifies it all.
>
> Bob, Wb4APR
>
There is a huge fundamental flaw in asuming equalety in all items, when 
someone sends an object with the same name as the object I was sending 
they will take over ownership when they edit it, this means if stations 
are identical to object in that behavior some can transmit an object 
with the same name is my station, this will stop my station from 
transmitting the position beacons after all objects and stations are the 
same once recieved including your own.
but if you are not transmitting anything else nobody will know your 
station is actualy life and all comunication to your station will grind 
to a hold unless it is local on rf, afterall no igate will know you are 
local.

73 de Andre PE1RDW

ps. I can't find any reference to tactical format in the specs, so I am 
guessing it is something you just came up with, I know it is hard to 
give up tight controll but sometimes it is better not to force your 
ideas of how you want it to be and let others define their own services 
within the current specs.



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