Sensitivity Adaptive Technology Of Optic-electronic Detection System

The sky screen is based on the sky,and its detection sensitivity is susceptible to changes in the brightness of the sky,resulting in unstable detection performance of the sky screen target.The dynamic range of the input signal of the sky screen is increasing by measuring the same target passing through different ballistic heights and the different target in the same ballistic height.Therefore,there is a need for a sensitivity adjustment method that can adapt to changes in sky brightness and a control method that adjusts sensitivity according to target size and ballistic height to ensure stable detection of the skylight target with appropriate sensitivity.This thesis takes the sky screen as the research object,and conducts in-depth research on its sensitivity adaptive performance.The main contents are as follows:1)Analyzed the influence of factors such as skylight optical system,photodetector,bias resistor,signal processing circuit and sky background brightness on sensitivity,and proposed a sensitivity adaptive control scheme;2)Using_the liquid crystal dimming film to adjust the luminous flux received by the photodetector,changing the resistance value of the bias resistor to change the frequency characteristic of the amplifying circuit,respectively designing the control circuit of the liquid crystal dimming film and the bias resistance,detecting the performance of the control circuit to change sensitivity,testing the correctness of the design;3)Designed the program-controlled gain circuit,the single-chip main control circuit and the single-chip control flow and software,and made the corresponding circuit board and debugged and tested;4)It is verified by system test that the sky screen has a good frequency response to the measured target,with the resistance value of the bias resistor being within the control range.By comparing the amplitude of the output signal of the skylight target before/after adaptive control,the adaptive control can reduce the amplitude fluctuation range of the output signal to about 45%.The method proposed in this paper can make the sensitivity of the sky screen change with the brightness of the sky,thus ensuring the stable detection sensitivity of the sky screen target By properly selecting the resistance of the bias resistor,the amplitude of the signal output from the skylight target under different projectiles and ballistic parameters can be kept substantially constant.The method can also be applied to sensitivity stabilization control of a type of photoelectric test system.