The Measurement Technology For Testing Paramenter Of Sky-screen

The target parameters of the sky-screen are the response time and burst shooting response performance.In the process of measuring the velocity of bullet by the sky-screen,if the response time of the sky is inconsistent,it will cause the error of velocity measurement certainly.Similarity,if the burst shooting response performance is too bad,it will also lead to lost or distort signal in high-speed burst shooting test.In order to ensure the precision and effective of velocity measurement by sky-screen,the response time and the response frequency of the sky-screen are detected periodically.However,the traditional horizon target detection is mainly aimed at the antenna sensitivity and response time consistency,and did not involve the detection of the above parameters.It is of great significance to design a convenient and quickest method to detect the working condition of the sky screen indoors,and to improve the fault detection,work stability and technology development.The results of this paper include the following aspects.1)The influence factors of the target parameters are analyzed.The working principle of the sky-screen is analyzed,and the influence mechanisms of the response time of the sky-screen are discussed from the photoelectric tube,the signal processing circuit,the optical machine structure,the bomb length,the elastic velocity,the track diameter and the sky illumination respectively.Compared the process of bullet crossing screen with the signal of sky-screen,the delay characteristics of the influence factors of the sky-screen are analyzed.The influence factors of the response time are divided into reaction time and rising time.2)The method of detecting the target parameters of the sky-screen is studied.According to the response time of the signal rising edge,based on the response time of the photodetector,it is determined that the inverted pulse signal is used as the LED point light source driving signal,and the feature point extraction method of the target image is studied.Use the test circuit to output a simulated projectile drive signal to drive LED point light source to produce instantaneous changes in light energy to simulate the projectile through the light screen of the physical process,and by measuring the interval time of the drive signal and light screen output signal,calculate the response time of sky-screen.Use a group of drive signals in accordance with a certain interval time on the point of light source,can check the burst shooting response performance of sky-screen.The method of detecting the target parameters of sky-screen is given.3)The detection instrument for target parameters are designed.This paper designs a test circuit for response time and response frequency parameters of the sky-screen,which is mainly divided into hardware circuit design and FPGA logic circuit design.FPGA logic circuit is based on counter-based unit,to achieve response time and response frequency detection pulse signal.Peripheral hardware circuit to the external band switch and dial input data through the microcontroller processing and address allocation,output to the FPGA.The front and rear panels of the detector are drawn,and the MCU program and signal generator are designed.4)The target parameters of the sky-screen are detected by the detection instrument,and the measurement data were analyzed.According to the test method,the response time of the sky-screen and the maximum radio frequency were measured.It is proved that the design scheme can meet the requirement of the accuracy of the target parameters of the sky-screen.The designed test circuit can realize the response time of the sky-screen and the burst shooting response performance measurement to meet the design requirements.