This paper discusses a method which uses laser techniques to distinguish targets between the enemy and Ourselves and a method which is used to modulate echowave signals.An all-direction detective system is composed of a laser transmitter and a receiver who are put on an image Stabilizing turntable and a group of laser detectors and reflecting prisms in multi-eye style. When this system receives the inquireing codes from inquireing direction(friend direction)

the modulatdr in front of the reflecting prism is controlled to reflect identified codes from the reflecting prism. Then these identified codes are received and distingushedin inquireing direction (friend direction).This system is very useful for distinguishing between moving targets from air to air

air to ground

and ground to ground etc.