US Patent 7521664 Laser direction detection

Apparatus for determining a direction of low power radiation originating from at least one source, the radiation arriving essentially collimated, the apparatus including an opening, at least two radiation sensors, a respective integrator for each radiation sensor, an integration enabler, a threat detector, and a processor, each integrator being coupled with a respective radiation sensor, the integration enabler being coupled with each integrator, the threat detector being coupled with the integration enabler, and the processor being coupled with the integrators and the threat detector, wherein the opening receives incoming radiation, the radiation sensors being located at different spatial locations behind the opening, each radiation sensor detecting at least a respective portion of the incoming radiation received from the opening and converting the respective portion of the incoming radiation into a respective electric signal, each integrator integrating the respective electric signal, wherein the threat detector detects threats and produces a threat indication for each detected threat, wherein the processor determines the direction according to the amounts of the electrical signals integrated by each of the integrators.