Computing MPH

[Ludis Langens]

steve ravet wrote:
> 
> Price on the Vbox was about $3K I think.  You're correct, it measures
> the doppler shift of the GPS satellite signals to measure velocity.  The
> GPS info itself isn't nearly accurate enough.

Even cheap GPS receivers use the satellite doppler shift to compute
speed.  I have an old GPS unit and somehow or other the doppler
calculation isn't always correct.  At times the GPS said my speedo was
right on, other times it implied an error of 5%-10%.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/


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