Active and passive composite laser holographic radar

Abstract

An active and passive composite laser holographic radar consists of a laser, a phase modulator, a beam splitter, an RF signal generator, a laser amplifier, a transmitting telescope, a local oscillatorretarder, a receiving telescope, a 2 x 2 180-degree spatial optical bridge, an A-channel CCD detector, a B-channel CCD detector, a control computer and image processing, thereby finally obtaining a target image of high sensitivity and high contrast. The active and passive composite laser holographic radar can realize passive, incoherent and coherent target imaging through active and passive composite applications, and has the capability of working all-weather, simple structure, and the effect of suppressing background light interference, which effectively improves imaging sensitivity, and isparticularly suitable for detecting dark targets at a long distance.

Description

technical field [0001] The invention relates to a laser radar, in particular to an active-passive composite laser holographic radar, which adopts a separate transceiver structure and includes three working modes: passive imaging, active non-coherent imaging and active coherent imaging. When the emitting laser is turned off, the natural light irradiating the target is passively imaged, and only the CCD intensity detection imaging is performed through the receiving system; when the emitting laser is turned on, active imaging of a long-distance target can be performed, and the laser passes through a phase modulator, a laser amplifier and a visual sensor. The field wave surface transformation is transmitted to the long-distance target through the transmitting telescope. The target echo passes through the receiving telescope and zoom system, and then performs heterodyne coherent detection with the transmitted local oscillator optical branch. The balanced coherent image is obtained t...

AI Technical Summary

Problems solved by technology

However, there are mainly two problems: ① The peak power of the pulsed laser is very high. When there is a strong reflection point on the space target, it is easy to cause APD saturation or even damage. Therefore, the anti-saturation ability of the detector should be improved; ② Higher timing accuracy , wide signal transmission, processing bandwidth and extremely high signal sampling rate have high requirements on the readout circuit, making the system cost very high

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