RussBoy

I've been trying out a new toy this last couple of weeks - a handheld PDA running bluetooth TomTom3 Sat Nav. I'm really pleased with the system (apart from the TomTom3 in car charger which doesn't work...) and have started using the GPS speed as a more accurate way of seeing what speed I'm really travelling at.

I know all cars are calibrated so the speedo effectively 'over reads' but when my speedo is showing bang on '80mph' the GPS records 71/72mph showing a possible margin of error in the calibration of 10% or so. To be fair, I do have a 'Type R' (hence an import) with a changed speedo dial (which could, I suppose, allow for some of the margin of error?)

Is GPS DEFINATELY very accurate (i.e, am I right to rely on this as an accurate reading) and has anyone else ever noticed any significant discreprancy between GPS and traditional speedos?

Cheers,


Russ

Redkop

I use GPS in my car and its spot on to the speedo. But if I use it on my Pajero import, it's about 10mph out.

harvey

iTrader: (48)

Remember there will be a delay on the GPS so it will show what your speed was a couple of seconds ago or something like that.

Granby

iTrader: (5)

I've got a Origin b2 and i noticed that the speedo over reads about 5mph from 70mph on wards, there is a delay with GPS but I've tried it at a steady speed and it still over reads.

Johnny_B

I have a Snooper S4 and have also noticed that even at a constant speed my speedo reads 60mph and the GPS reading is 54mph. In my old car it was only 1mph out when at a constant speed.

RichieD

I have a JDM import... with a KPH to MPH convertor (electronic), TomTom 3 *and* Origin B2... and they all show the same speed! (allowing 2 second refresh for the GPS based bit of kit)...
So I'd answer your question... YES, GPS is accurate.

scottywrx

I have the same with TT2 on IPAQ .. MY01 WRX speedo showing 70 mph Ipaq shows 63mph ..
GPS is the accurate one based a few trials I did last year ..