Very high angular resolution laser beam rider detector having a gated

Abstract

A laser warning receiver (LWR) having an ability to not only detect a low power level laser source, such as a pulse train emitted by a laser beam rider, but to also provide a high angular resolution in determining the angle of arrival of that pulse train. The receiver includes a lens/filter arrangement for a large area photodetector to detect an incoming signal from an emitting source and a high gain amplifier to amplify the signal which is then applied to a synchronization generator that generates a digital pulse train with pulses corresponding to peaks in the incoming signal. The digital pulse train is applied to a code breaker where the code is analyzed and a further code is generated anticipating the arrival of further pulses in order to verify the code. That further code is applied to a time gate generator which generate a code, synchronized with the incoming signal, that controls the high voltage of a gated image intensifier which is coupled to a video camera. Gating of the image intensifier is synchronized, as a result, with coded emissions from the source so that a video image from the camera can be displayed on a monitor and more easily differentiated from the background. The width of pulses generated by the time gate generator, the video camera, gain of the gated image intensifier, gain of the gated image intensifier and an auto-iris zoom lens coupled to the image intensifier are all under the control of a video processor.