Data that is available
- GPS position and velocity, normally at about 18Hz
- 3 axis accelerations at 100Hz
From this basic data the following can be calculated in the software:
- Total acceleration or type grip
- Vehicle power at the wheels
- Motorcycle lean angle
- Lap and sector times
- Time slip and time slip rate, that is how much faster/slower than a previous lap/sector
- Simulated time slip and time slip rate, that is how much faster/slower than an idealised case
Whilst the GPS data from a GoPro camera is generally quite good, the accelerometer data can be problematic. The issues are:
- For the acceleration data to be accurate, the camera must be mounted square and level. If not, or the camera moves the accelerometer data is largely unusable.
- The GoPro quite often vibrates lots on its mount, this is measured by the accelerometers and needs to be filtered out.
- The GoPro stores the accelerations axis and sign conventions differently on different models, and there isn’t anyway for the RT software to know how this has been done. Further we don’t really trust GoPro not to change this in future firmware. As a result our software tries to automatically identify the accelerometer axis based on matching accelerations with GPS data. That generally works okay as long as there is some significant G-forces in the file, the GPS data is okay, and the camera is mounted straight/flat in the car.
As an alternative to using the GoPro accelerometer data, our software also calculates accelerations from the GPS data, so that is an alternative when the sensed accelerometer data is not useable. That is in the GPS variables, “GPS lat accel” and “GPS long accel”.