An optical detection system for detecting an incident optical signal is described. The system includes an optical package adapted to collect the incident optical signal and directed it to a detector array that is coupled thereto. The array outputs electrical signals to be analyzed by a processor. The processor is adapted to iterate algorithms using the signals to calculate an incident angle of arrival for the incident optical signal and a range of the source of the optical signal to the system based on the angle of arrival calculation. The processor is further configured to discriminate the optical signal spectrally to calculate wavelengths thereof for false alarm rejection.