Optical biaxial angle sensor

A fast and accurate non-contacting angle sensor. According to one aspect of the described sensor and method of operation thereof, the angular orientation of an inner payload relative to an outer structure is monitored with a 2 axis optical angle sensor for azimuth and elevation angles. The sensor operates on the same principle as an autocollimator, thus it measures both azimuth and elevation angles simultaneously. The angle sensor measurements are highly accurate in the angles of interest, while having low sensitivity to translation in three axes and low sensitivity to roll angle between the inner payload and the outer structure.