I have not had much time but at least I have tried to solve the problem of excessive vibrations when heli is tested on the stand. As the vibrations reach measurement limits of the sensors the only way is mechanical dumping.
Thus I created a new IMU board holder consisting of a heavy iron plate & soft foam.
Here it is
Besides this I have decided to add support for centripetal acceleration calculation in the INS as it is intended to be used with some regular plane models in the future (when velocity and rates are know calculation is pretty easy: ).