No 0mph start data in Performance Calculation

[fast_grandad]

I have a set of data recorded from a standing start down a straight and level runway. GPS coverage was excellent. I have trimmed the data so that the file starts at zero long 'g' and zero speed but cannot get the Performance Calculation table to show any times from 0mph. 10mph to any speed or even 5mph are fine but not from zero. Trigger criteria are default at .02g and 3mph and I have tried other settings to no avail.
I am planning to use this facility to test different hill climb start-line launch strategies so need it to work.
A related question - can the GPS input influence be disabled so that speed is determined by integrated acceleration only? This would take out gps speed noise from very short distance straight line grip/acceleration tests.

[Support]

It can be a bit tricky sometimes to get this working as the software is a bit sensitive to the triggering data. I've made the software development guy aware of this and they will have a closer look.

The way I normally go about getting the 0-?? times is to bring up the performance tables, then open an X-Y plot of speed and longitudinal acceleration together and then "shift drag" across the graph to get the relevant information. By doing that you can see any discrepancies in the acceleration and speed data which might be causing problems.
Moving the Acceleration trigger to 0.05 or 0.1g normally does the job.