Harry's GPS Suite Forum

I have some data that seems to be missing lateral accelerations. I use an external GPS receiver at 5 Hz with an iPhone 4S. While at Watkins Glen this week, I took data each session and most sessions provide data like this for lateral accelerations:



However, during a couple of sessions this is what I see for the lateral accelerations - they seem to be missing completely, though I have good fixes and speeds etc. :



Is this data missing? Can I get it somehow so I can review these laps for lateral g's?

Thanks for any help here.

--Jim

Hi Jim,

This happened in early 17.0.x versions frequently but should happen intermittent only for v17.1.x. No acceleration means the acceleration sensor lost calibration / has not been calibrated when leaving the pits. v17.1 has several mechanisms in place to not lose calibration while driving. As a workaround for your existing laps, please use the calculation option available in Lap Details. It will recalculate acceleration from GPS. The applied function is not optimized for 5 Hz GPSes, but will generate values better than nothing

- Harry

Thanks! Will do.

Is there any indication on the display that I am not calibrated? I can watch for this in the future.

(edit: this happened with 17.1.5 software version)

In case you use the video view, make sure the acceleration indicator is centered before leaving the pits. In case it is not, touch the acceleration circle to start over. Please do all of this while standing still. Do not rotate or change the mounting position while driving.

- Harry