| With the increasing accuracy of modern weapon shooting,higher requirements are put forward for accurate measurement of impact position in shooting range test and actual combat drill.According to the demand of impact position detection,among many detection methods,optical inspection methods have the advantages of relatively high measurement accuracy,relatively low cost,and small size and light weight of the system,and has been widely used in the detection of the impact point of modern bullets.In this method,optical systems play a vital role throughout the inspection process and its overall performance will affect the tracking and detection ability of the whole system.In this paper,a common aperture continuous zoom optical system which can simultaneously image in visible and long wave infrared wavelengths was designed according to the problems of limited tracking resolution of impact point targets in a far-away,wide and complex environment.The refraction imaging is adopted,and the design method of common aperture and prism splitting is adopted.The visible and long-wave infrared bands share the same incident window,and the synchronous imaging of visible and infrared bands is realized through prism splitting.In this paper,an optical imaging system is designed for detecting the position of impact point,this paper proposes an optical measurement method for cross-positioning of two stations,site measurement error and baseline length on the positioning error of two stations is deeply studied.According to the principle of impact point detection,through the correlation analysis and calculation of the performance parameters of the selected detector and the requirements of the detection range of the system,determine the technical specifications of the optical system.Based on the geometry method,a program can be written to quickly solve the initial structural parameters of the most adaptive multiplier ratio,and the initial structural parameters suitable for the variable ratio of this topic are obtained.The visible light system is 10× continuous zoom of18～180mm,and the long wave infrared system is 2× continuous zoom of 24～48mm.Through the achromatic theory,the materials suitable for the common aperture part are selected.The dual-band common aperture optical system was optimized and the image quality was evaluated.In order to ensure that the image surface can keep stable and get better imaging effect in the whole zoom process,the zoom curves of the zoom group and the compensation group are drawn.Then,the thermal and optical characteristics of the zoom system were analyzed to ensure the reliability of the design environment of the optical system according to the temperature environment requirements of the impact point detection system from-40℃ to+60℃.The mechanical and electrical active thermal detracting method was used for thermal detracting of the optical system,and the imaging effect of the entire optical system was comprehensively evaluated.In order to achieve the actual machining requirements of the system,the tolerance analysis of the system was carried out;the detection distance analysis of the system is carried out to meet the actual use needs.After the research and analysis of the designed system show that the modulation transfer function value of the system reaches above 0.32 at 145 lp /mm in the visible band and 0.23 at 42 lp /mm in the infrared band.The maximum root mean square values of each field of view in the infrared band are all within the size of a pixel,and the image surface of the system is clear and the image quality is uniform.The two zoom curves drawn are smooth without inflection point.Monte Carlo is used to analyze the tolerance of the system,the tolerance is relatively loose,meet the machining requirements;Finally,the range of the system is calculated,and the detection range of visible light and long-wave infrared reaches more than 10 km and 4 km respectively.The structure of the whole optical system is relatively compact and the imaging effect is relatively good,which meets the detection and identification requirements of long-range and large-scale targets in the field of ground detection. |
