Abstract:Laser threat warning is a technique for intercepting, measuring, recognizing and direction finding the threatening laser from enemy. It is an important technique for optoelectronic countermeasure. Laser warner is able to recognize the threatening laser, confirm its character, judge threatening level, and quickly give out warning signals, which can provide optical payload or satellite enough time to take effective measures to protect the satellite system against fatal laser attacks. The laser warning technique for satellite is discussed. A threatening direction detect method based on Position Sensitive Device(PSD) is presented. On condition that laser pulse width is greater than 50 ns, an orientation resolution better than 1 mrad can be obtained within ±1°. Through broadening its receiving field by lens optical design, the requirements on the warning field of satellite optical payload or satellite can be satisfied.