Below is an export from our recent test at Almeria to illustrate the driving line accuracy. Tested GPS is eTesta GPS7 Dual (2 antennas), both receivers running at 50Hz. Brake pressure data is read by GPS7 from the Yamaha CAN bus.
Result is very good for a 50Hz GPS. The line outside is Out Lap and should be discarded, it has nothing to do with GPS.
Laps are within 0.7m radius which is good. RTK would give more accurate results but there are no RTK devices higher than 10Hz rate. If there is, let us know and we'll correct this...
This data has now only 2 fastest laps to eliminate in/out laps and is the hard braking after finish line.
From this data we can point out exactly for example where the braking points are and how much braking force was applied. This wouldn't be possible from 10Hz GPS data because the sample rate is not fast enough at high speeds and often results are averaged. eTesta GPS7 output is not filtered and is instantaneous (Filter is available if needed).
You can clearly see that the driver was braking much much later.
Here is how throttle was applied by the driver during these 2 laps. You can see that the driver is releasing the throttle briefly to correct.