Calculating Acceleration from GPS

Hello

We are trying to use a programmable tracking box to measure the acceleration of a vehicle. We log the speed from the GPS (Sirf Atlas V ) sensor every seconds in order to check for harsh acceleration/deceleration. Some of the results we are getting coming back for the speed look a bit strange.

This is a sample of our data
Second 1: Speed 13.58 MPH , Sat Count 10, HDOP 0.880
Second 2: Speed 31.3 MPH, Sat Count 9, HDOP 0.931
Second 3: Speed 41.5 MPH, Sat Count 9, HDOP 0.931

It just looks a bit unbelievable that a car will be able to accelerate from 13.58 MPH to 31.3MPH in a second. The sat count and HDOP are both very good but it still seems a bit strange.

Any ideas if this looks reasonable because to me it looks like a very large acceleration. Has anyone else had experience of calculating acceleration from gps speeds?

The car the testing was performed on was a Diesel Alfa Romeo Giulietta 2 liter

 

You would need to use a very high accuracy GPS device and have it time-stamp the speed records.

Say every 1/4th a second it checks for speed and logs the time.
You'd have to ask a math expert on how to figure out acceleration over that span of time but it is possible.