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[aprssig] Tracker Decaying algorithm

Robert Bruninga bruninga at usna.edu
Thu Mar 23 02:19:27 UTC 2006


>>> johnstonwes at gmail.com 03/22/06 8:13 PM >>>
>Hey, a way to limit mobile's sending the same position 
>while parked all day is to use the dupe checker 
>with an extended timer... like 255 seconds.

That is how APRS was designed (APRSdos).  There 
was no such thing as fixed rates.  Everything that
did not change, always doubled the period to the
next transmission.  Positions, Objects, Messages, etc.

If the posit does not change, then the period is 
doubled for each additional packet.
If a 1 minute mobile stops, then his next packet
is 2 minutes later, then 4, then 8, then 16, then
30 and reamains at 30 until he moves again.  Then
it instantly goes back to 1 minute.

It does not instantly go to 30, becuse the -fact-
that he -stopped- is valuable info too, and so
it needs the decaying redundant refresh too until
the data gets older and older.

APRS was never intended to have fixed rates.
Its just that many clones used it because it was
simple.

No reason why trackers cannot do this too.

de Wb4APR, Bob






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