US Patent 9851442 LADAR augmented infra-red (LAIR) sensor

A system, method, and apparatus for detecting and tracking a target are disclosed. The disclosed method involves receiving, with an infra-red (IR) fine track sensor, a IR signal from the target. The method further involves determining, with at least one processor, an estimate of a direction of the target using the IR signal. Also, the method involves transmitting, with a Laser transmitter, a Laser beam towards the direction of the target. Further, the method involves receiving, with a Laser receiver, the Laser signal after it reflects off the target. In one or more embodiments, the Laser receiver is a photon receiver (e.g., a geiger-mode avalanche photo-diode (Gm-APD) receiver).