[aprssig] Dead Reckoning in APRS

Stan - N0YXV n0yxv at gihams.org
Sun Jun 18 12:03:10 CDT 2006

> Believe me, the Navy knows how to present real-time
> information (including ambiguity), latency and all manner
> of attributes, and it does not require the operator to
> go around clicking on the hundreds of targets that may
> be attacking him.
> APRS provides for all these capabilities to display in
> real-time, all the information the viewers need to see
> to be able to fully comprehend the tacctical situation
> at a glance.  It is too bad that many APRS clients
> other than the original left out many of these features.

If you've ever watched NASCAR online you'll see something similar to "dead
reckoning". The position you see on the screen for each car is only the
"projected" position of the car. As near as I can tell they poll the cars
about 4 or 5 times around the track and use that data to project where the
car should be. When a crash occurs the car continues to be shown as moving
around the screen. It continues on its course until it reaches one of the
places where they poll the cars. Then that car suddenly goes backward to the
position on the track were it really is. With this system they are able to
show an icon that constantly moves around the track rather than simply
jumping from polled position to the next polled position.

> Be careful about comparing arm-chair casual APRS observing
> with what it was designed for, and that is tactical real-time
> display for busy operators with other communications
> responsibilities while operating under stress.
> de Wb4APR, Bob

More information about the aprssig mailing list