Fragment Velocity Measurement System Calibration Method Research

The study of fragments’initial velocity and velocity distribution is the key to analyzing fragments’ flying law and studying the warhead effect. The modern weapon system request higher and higher for the warhead fragments velocity index, the fragment velocity measurement precision requirements are also getting higher and higher. At present, there are no related standard velocity source and standard speed setting system, which brings certain difficulty to the velocity measurement system calibration.In this paper, the projectile velocity calibration method is reviewed, analysis the existing problems of various methods, on this foundation, the method of measurement of fragment velocity through combined laser screen target calibration device is given out, namely "standard" speed monitoring system.In the design of "standard" speed monitoring system, optical computing is combined, a parallel light lens is designed, parallel laser screen is made up of multi group parallel light, and the combination of the photoelectric conversion element seamless splicing technology, eliminates the detection blind zone effectively. In the signal processing circuit, the design of the comparing circuit with hysteresis, improves the anti-interference ability of the circuit greatly, and the flexible and adjustable shaping circuit is designed. Considering the system service, measurement precision and convenience of maintenance and debugging, horn nut and screw are used repeatedly in the mechanical structure design. The mobile of target frame and the target space adjusting can be completed flexibly, that the experiment can also be completed in minority participation.The design of high-precision chronometer combine pulse counting method with quantitative delay method. TDC-GP2measurement chip is used in the system,and MSP430F149low power MCU is selected as the controller. FPGA is used to design a pulse signal generator. Through experiments on the measurement accuracy, the assessment shows that the measurement instrument precision can reach81.9ps.By firing practice on the "standard" speed monitoring system, the experimental results show that the system precision is less than0.1%. So the use of "standard" speed monitoring system to calibrate other velocimetry system is able to meet the requirement of quantity value transfer.