[kag] Re: GPS accuracy?
- From: Hoover <mlehotay@xxxxxxx>
- To: kag@xxxxxxxxxxxxx
- Date: Mon, 16 Aug 2004 12:28:42 -0400 (EDT)
On Mon, 16 Aug 2004, Gordon Campbell wrote:
> Does anyone know how reliable the speed reading on a GPS is? My sTrex
> consistently insists that my car is travelling at exactly 5km/hr less
> than the speedometer. hmmmm.
I saw the same thing with Root's old car. I assumed it was a calibration
issue with the speedometer. I should check again in the new car. Now that
I think of it, this is more likely related to the GPS receiver not
including changes in elevation in its calculations. I think it projects
your position onto its mathematical model of the Earth and measures your
movement along that. So if you are driving up a hill, your projected
motion would be slower than what your speedometer says. Or maybe the model
is not quite parallel to the surface of the Earth in our part of the
world. I'm just guessing at all of this, of course.
Hoover
------------------------------------------------------------
Kingston Area Geocachers mailing list
//www.freelists.org/webpage/kag
Other related posts:
