How slow can you go and still get a decent speed reading on GPS?

During the bad old days we used to blame all the errors on SA but
I knew once that was turned off we'd see the real ones.  In fact
I don't think the doppler ranging was even affected by SA which
is why the velocity readings were more accurate than the location.

I haven't had one of these to play with in recent years.

Barry

At 04:08 AM 9/5/01 +0000, you wrote:
>Depends on if you want water speed or ground speed.  If you want ground
>speed use a GPS.  If you want water speed use a paddlewheel.  You can
>buy the paddle wheel speed indicators at any marine electronics stores.
> They have pulse outputs.  Some of the newer Airmar smart sensors have
>direct NMEA outputs.  Airmar is also working on a smart sensor using a
>correlation technique with no moving parts.  I have been bugging them
>for the OEM version for over a year and they are still having problems
>with it.
>
>Mark Skeels wrote:
>
>>Greetings, PICsters.
>>
>>How would you go about creating a device to measure and provide a real-time
>>readout the speed of a canoe on a lake or a river? (using a PIC, of course?)
>>(...or not...)  :-) Only thing I can think of is GPS, but perhaps sonar, or
>>something?
>>
>>
>>Mark Skeels
>>Engineer
>>Competition Electronics
>>meskeels@earthlink.net
>>
>>Soli Deo Gloria!

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