Sample rate
GPS receivers usually update every second, but most loggers won't store every position. Back when I worked in telematics (many years ago, to be fair), the actual sample rate was every 20 seconds or so. Based on a normal-ish car, it would be very easy to accelerate from standstill to 60mph - and be doing double the speed limit - and then back to under 30mph again all within a single sample. A policeman could clock me at 60, but my log might only show 30, even though I had indeed done 60.
Biting the hand that feeds IT
