US Patent 11402205 Sensor for a rotatable element

A sensor unit mountable on a rotatable element on a platform that is itself movable, and includes an orientation sensor arranged to take measurements that are dependent on the orientation of the sensor unit, a processor arranged to derive a rotational position signal representing the orientation of the rotatable element from the measurements, and a buffer arranged to buffer a series of recent measurements taken by the orientation sensor over a predetermined period of time. The processor derives the rotational position signal making a correction to compensate for the effect of the motion of the platform on the measurements on the basis of the overall series of measurements buffered in the buffer.