Aspects of the present invention relate to systems, methods, and computer program products for tracking an orientation of a first object. The system includes a light emitting device located relative to a second object at a fixed predetermined position; a sensor having a photodetector array that is configured to receive incident light emitted from the light emitting device, the photodetector array being mounted on the first object; and a processor coupled to the photodetector array, the processor configured to determine the orientation of the first object relative to the second object based on an angle of incident light detected by the photodetector array from the light emitting device.