Re: accuracy of Garmin Edge 305

Testing FMP wrote:
Thanks to everyone for some very useful knowledge.

To finish off the altitude question, I wonder if a user can manually calibrate the altimeter from a map, or whether the GPS is the only calibration?

You can't calibrate it manually. It is not necessary. My experience is, if you turn on the unit and wait for it to lock on the satellites the altitude that is shown is not correct. If you wait a couple of minutes you see the altitude changing to the 'correct' value within 5- 10 meters. After that it is amazingly accurate.


Now I hope you will bear with me while I get slightly obsessive. Now I'm wondering how accurate the Garmin is for the measurement of distance travelled.

The measured distance is OK. The current speed is very jumpy.


Does the Garmin use the wheel speed sensor (when available) for distance only when it loses the satellites (in a tunnel, etc)

Yes. I can't understand why they do that.

or to continuously correct/calibrate the GPS measurement?

No.




Let's assume there is no wheel sensor. How accurate is the GPS measured distance if you are moving on a level surface? What would it measure if taken around a 1/4 mile oval track for a given number of laps? Or, to get even more ridiculous, how small would the track have to be before Garmin decided it wasn't moving?

You can turn off the GPS. After that the unit uses the wheelsensor. Don't be obsessive about it. It is my experience that the measured distance is as accurate as a wheelsensor.

Lou
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