Research On Accuracy Of Liquid-crystal Optical Phased Array Imaging Laser Radar

Compared with mechanic scanning method, Optical phased array (OPA)technique plays an important role in imaging laser radar scanning device because offast scanning speed, flexible pointing and high imaging resolution. Liquid-crystaloptical phased array(LCOPA) possesses many advantages in application due to itseasy control, low power and practical operation. Improving the steering accuracy andranging accuracy of LCOPA-based scanning imaging laser radar is the essential factorto realize applications. The higher steering accuracy and ranging accuracy the LCOPAlaser radar can obtain, the more accurate target identification it can get. Obtainingmore details of the structural information of the target has broad application prospectswith a high military value and potential in target acquisition, precision target trackingand so on.This essay gives an overview of the development of models of optical phasedarray (OPA), and the development of imaging laser radar based on OPA’s scanning. Itcan be seen that there is few research on the OPA scanning imaging laser radar whichis very significant in this field. The principle of OPA is shown, and then thephoto-electric characteristics of liquid-crystal and the principle and model of thecontrol of LCOPA are introduced. A laser radar system adopting1-D liquid-crystaloptical phased array scanning is built, as the basis of the following chapter of thestudying of the laser radar’s accuracy. The standard and the influence factors of theaccuracy of laser radar based on1-D LCOPA scanning are analyzed. The voltagequantization error and the extension of laser pulse, caused by the side lobes, areanalyzed. The steering error and ranging error are10-1mrad and10-2m, respectively. Aplatform of LCOPA-based scanning imaging laser radar system is setup andexperiment about steering and ranging accuracy are performed. Steering accuracy isenhanced using the method of iteration phase compensation and ranging accuracy isimproved using the method of side lobes restraining. Simulations are carried out toprove that the methods are feasible, steering accuracy is enhanced to0.04mrad from0.13mrad when n=16and ranging accuracy improved to0.021m from0.040m.