How accurate is MPH on my 315?

[+DadONine]

Hey all,

I've been drivin' around with my new Magellan 315, and I've noticed that the MPH on my GPS is fairly well in line with my speedometer on the dashboard, within a couple MPH. But say I want to be REALLY accurate. Which reading do I believe more: the GPS or the speedometer? Which is more accurate?

That is all,

DadONine

[Kerry.]

The GPS.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[+Renegade Knight]

Ive used the GPS to check my cars. Over time I've learned that my van is good, and the GPS confirmed that. It also confiremd that my new oversized tires corrected my speedometer problem on my Bronco.

[+user13371]

quote:

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...the MPH on my GPS is fairly well in line with my speedometer on the dashboard, within a couple MPH....Which is more accurate?

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Assuming you have a really good fix, the GPS *may* be more accurate. But some things may be its undoing.

 

1) Low speeds. The slower you are moving, the less accurate the GPS will be on speed (also on it's trip odometer). It will tend to shortchange you. Usually not a big deal whilst driving -- but more at walking, jogging, or bicycling speeds.

 

2) The GPS only updates once per second, and shows you sped based on the second just completed. So the GPS reading will be in doubt during accelerating or decelerating.

 

3) If you don't have a good and consistent signal, all bets are off.

 

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LDR.