Abstract: The sensor is particularly suitable to determine movement between a ground vehicle or aircraft over a ground surface, and a portion of the reference surface (10) is imaged on a grid plane (12, 30, 40) which, in accordance with the invention, is formed as a photo-sensitive transducer, for example a plurality of photo-sensitive diodes formed on a single chip and suitably connected in a grid or matrix pattern, made, for example, by a planar process by monolithic integration. Correlation-optical measurement of relative movement thus is simplified, and precise grid structures can be readily made, the output signals from the individual photo-sensitive junctions being summed and, if interdigited grid structures are used, the so summed signals can then be subtracted from each other to eliminate ambient light, or slowly varying low-frequency components and derive only a movement signal.