This allows the filter to adapt to variations in GPs quality.
The range of adjustment in observation noise is limited to the range between a lower limit set by the GPS observation noise parameter and an upper limit set by the no-aiding observation noise.
A larger position uncertainty is required when flying without GPS to reduce tilt attitude estimation errors caused by vehicle manoeuvring. This needs to be tuneable to allow optimisation for different use cases (e.g. outdoor vs indoor).
Fix bug where noise parameters were not being squared when calculating the observation variance.
Use GPS reported speed accuracy to set velocity observation noise and use the parameter to set the minimum.
Set conservative defaults as a baseline for tuning
Add a missing parameter for magnetometer observation noise.
Correct error in definition of magnetic heading observations noise (previous parameter defined the variance directly, not the noise).
Scale vertical GPS noise to allow for average EPV to EPH ratio.
Update documentation and display names for consistency.
