Laser retroreflector system for identification of friend or foe

A covert laser retroreflector system for cooperative battlefield friend-or-foe target identification, said system comprising:

• a laser interrogator with clocked transmitter and dedicated large aperture receiver portions therein wherein said transmitter portion transmits an encoded cryptic interrogation message on a first laser pulse toward a target followed by a precisely timed clocked unmodulated second laser pulse and wherein said receiver portion receives a retroreflected reply signal from a friendly target;
• and
• a laser retroreflector receiver/transponder positioned on said friendly target for receiving said first and second laser pulses therein clocked in synchronism with said clocked transmitter and receiver portions in said interrogator, said laser retroreflector receiver/transponder comprised of detector lens and a detecting means for detecting said first and second laser pulses and a decoder/encoder for decoding the detected encoded cryptic interrogation message first laser pulse and the detected unmodulated second laser pulse and collecting optics comprised of a collecting lens and fiber optics bundle with its input at the focal point of the collecting lens and a collimating telescope comprised of converging lens at the fiber optics bundle output and diverging lens for collecting said first and second laser pulses and a modulating retroreflector positioned on the optical axis of said collecting optics for receiving said first and second laser pulses from said diverging lens wherein said modulating retroreflector is in the off state until modulated in the on state by a signal processor in said decoder/encoder wherein said modulating retroreflector is modulated only during the time that said unmodulated second laser pulse is received and only when a correctly encoded cryptic interrogation message in said first laser pulse is detected by said detecting means and is decoded by said decoder/encoder for activating the signal processor in said decoder/encoder clocked in synchronism with said unmodulated second laser pulse wherein said modulating retroreflector modulates the unmodulated second laser pulse in near real time to produce a retroreflected modulated reply signal with the proper preassigned code therein which is encoded by said decoder/encoder and is retroreflected back along the optical axis of said collecting optics to said dedicated receiver of said laser interrogator which is optically aligned with said modulated reply signal for decoding therein to determine friend-or-foe target identification.