Miata Mailing List: February 1997, Message #11
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   From: (none)

Subject: Re: Inaccuracies of GPS - Re: Tach gauge and other gauges

   Date: (none)



Previously on GPS, Dan Scolnick  said...



> 	I've been thinking about the GPS inaaccuracies.  While it is

> rather unpredictable from time to time to take you back to the EXACT same

> location (it will be off 100 meters over a number of tries) my speed

> calculations on cars speedometers have been 100% reproducable.  Since

> measuring speed doesn't really car about where you are but how you are

> moving I think that the built in military inaccuracy for location may not

> have the same inaccuracies regarding speed.



Possibly not, but my thinking is that since the speed is determined by

calculating how long it took you to go from where you were to where you are,

it would be affected each time a position was calculated.  It is possible that

while using the same satellites, your error is exactly the same, in which case

the speed calculation would not be affected.



	-John



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John Freas (jfreas@gte.net)

Red '90 Base

Clearwater, Florida

Team Roebuck

Team Voodoo

Team Redline MTL

Team No hardtop posts

Team "I have no idea what those dimple things on the windshield frame are

for."

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