[Cole]

Originally Posted by Shinigami301

Interesting- but your view differs from this:

http://gpssystems.net/accurate-gpsbased-speedometer/

Very biased view. I have a GPS tracker in my work truck. Guess how it gets its speed readings? The OBD2 port.

You better have a damn good GPS to be able to calculate speed in real time with any accuracy. Ie, sub meter and sub second sampling. The whole 10m+ of accuracy really won't cut it here.