[aprssig] KC8UCH balloon over western PA right now, reachingNE Maryland by 10am

Robert Bruninga bruninga at usna.edu
Mon Apr 2 15:14:22 CDT 2007

> How about by speed.  If the speed goes to zero then you 
> are probably on the ground.

I like the altitude better.  If increasing or constant, keep to
the once every 10 minute turn-on-fix-update-shutdown to save
battery power.  But, each time you turn on and get a lesser
altitude than before, then leave GPS running.  This algorithm
works fine too when it hits the ground and the altitude is no
longer changing.  Then it goes back to every 10 minute update
for 5 times the battery life.  And can even trcak it if someone
carries it away...  Bob, WB4APR

> >> Since most trackers only have two mode, maybe a way to shut

> >> off the GPS would be via impact sensor of some sort.  

> > I'd say turn it off based on altitude changes.  If the
> > doesn't change by more than XXX feet between reports, you
> > down on the ground.

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