Signals froM a solid-state electro-optical line sensor, which samples a two-dimensional image brightness function in time and space, can be digitally processed to extract the ground velocity vector of relatively slow, autopilot-controlled aircraft such as mini-RPVs (remotely piloted vehicles). This sensor can be rotated into the direction of motion by a stepping motor which is controlled by a computational unit using simple easily realizable algorithms to keep the sensor in alignment with the velocity vector as well as to compute its magnitude. Together with other instruments already installed on board the aircraft, this combination of sensor and computational unit may form an instrumentation setup which can be used in passive, autonomous navigation systems. Computer simulated experimental runs proved that a sufficient degree of directional sensitivity and overall accuracy can be attained with the proposed method.
"Airborne Ground Velocity Determination By Digital Processing Of Electro-Optical Line Sensor Signals," Optical Engineering 21(2), 212370 (1 April 1982). https://doi.org/10.1117/12.7972912