Hi, I didn’t know where else to put this. I figured you guys would know lots about GPSr stuff. Is the speed shown on a car GPSr more accurate than the speedometer?? I know that the speedometer accuracy depends on the circonference of the tire and if there’s too much/little air it affects it. I’ve had people (that don’t know anything about electronics or internal GPSr function) tell me that the speed (kph or mph) is more accurate than the speedometer. Are they right?
Denis.
I think car speedo’s have an error ranging between 5% and 10% (maximum allowable error.) The most car manufacturer’s tune the speedo’s to be 5% slower than the actual speed.
The majority of gps receivers will give the velocity accurate to a error of 0.1m/s. If i’m not mistaken, the velocity is calculated using the doppler shift.
In short, yes they’re right.
I can confirm this as well, it was in the news a few years back that all car manufacturers slowed the speed to abotu 3-7% depending on the manufacturer. I think the GPS is more accurate.
Thanks, that’s the answer I was looking for.