Study On Cat-eye Effect In Laser Tracking System

Photoelectric sensors with optical imaging systems are commonly used in weapon systems,such as optical guided missiles,offensive,reconnaissance drones,sniper scopes,etc.They have become the core components of modern sophisticated weapons.Studies have shown that the optical systems with cat-eye effect can be used to achieve the detection and tracking of optical guided weapon systems,optical reconnaissance systems,optical sighting systems,and so on.In this dissertation,the study of the cat-eye effect of the optical system aims to apply it to active laser detection and target tracking systems to improve the detection sensitivity and tracking accuracy.The paper establishes a simulation calculation model for the cat-eye effect of the optical system when laser light is irradiated.Using this model,three aspects of the study are conducted,include:(1)By analyzing the laser echo powers of ideal normal incidence,oblique incidence and defocus conditions,then main factors that affect the echo power are determined.(2)In the case of a Gaussian laser beam,the influence of the intensity distribution of the incident light field on the echo intensity is discussed.(3)In the case of laser oblique incidence,the characteristics of the cat-eye effect echo signal propagation direction were analyzed.On this basis,the relationship between echo power and incident power,the relationship between echo power and defocus amount and the relationship between echo power and incident angle are obtained.The influence factors of the maximum detection distance of the cat-eye effect are obtained.And the relationship between the propagation direction of the echo signal of the cat-eye effect and the incident angle of the laser are also determined.This lays a theoretical foundation for the application of cat eye effect in detection.The paper establishes an experimental device to systematically measure the cat-eye effect and studies the detection effect of avalanche photodiode(APD)and CCD photoelectric sensor on the cat-eye effect.The main contents of the experimental study include:(1)APD is used to detect echo signals of the cat-eyes effect.When the laser wavelength is 532 nm,the ratio of the cat-eye effect reflection signal to the diffuse reflection echo signal is about 30 times.This fully demonstrates the feasibility of cat eye effect in detection.When the laser wavelength is 1064 nm,this thesis studies the difference in echo amplitude of the cat-eye effect in case of opening and closing the mechanical shutter of the camera.Based on the difference,the working status of the detection target can be effectively judged(2)Experiments are conducted to investigate the difference in the detection effect of the cat-eye effect between the transceiver detection system and transmittance and optical path detection system.When the detection distance is 80 m and the incident laser power is 2.83 W,the amplitude of the echo signal is measured to be 21.10 m V by using the transceiver detection system while the amplitude of the echo signal measured is 308 m V by using transmittance and optical path detection system.When the detection distance is 230 m,the transceiver detection system does not detect the echo signal.With the help of transmittance and optical path detection system,the echo signal strength is as high as 183 m V.Experiments results show that the transceiver optical path detection system is more suitable for detection.(3)The CCD photoelectric sensor is used to detect the cat-eye effect.Experiments have found that the echo energy and the incident optical power are approximately linearly increasing.It has also been found that the amount of defocus in the plane of the photosensor of the optical system can severely affect the cat-eye effect.The experimental data showed that when the echo energy decreases sharply,the defocus amount increasing,the echo light field distorting and the defocus amount being 6mm,two peaks appear.(4)The CCD photoelectric sensor is also used to measure the spatial characteristics of the cat-eye effect.The data showed that the closer to the center of the spot,the greater the echo energy is.The distribution of echo energy is basically consistent with the distribution of the incident light field.Using the relationship between the light field distribution and the echo energy distribution,the distance from the target to the spot center can be determined,which can provide a basis for the target tracking system to further improve the tracking accuracy.