The Time And Target Distance Calibration Technique For Muzzle Velocity Measuring

Muzzle velocity measuring device is a directly mounted in gun tube to measure the muzzle velocity of the projectile, the factors that affecting the accuracy of muzzle velocity measuring device are the target distance and the time of projectile passing through target distance, thus the speed measurement equipment needs a calibration before leaving the factory. The devices used for velocity measurement of projectile are coil target, screen and sky screen. These kinds of devices are far away from the gun muzzle position and obtain long target distance. Besides, the error brought by conventional measurement has little effect on velocity when using devices above. However, muzzle velocity measuring device is arranged on the muzzle, thus, the target distance is short, time measuring instrument need high precision, small bias would enable velocity change larger, so it is necessary for precise measurement calibration.Basing on the muzzle velocity measuring device principle, this paper analyzes the main factors effect on muzzle velocity, and describes the muzzle velocity measuring device time and target distance calibration method. In time calibration, this paper designs projectile signal simulator. The projectile signal simulator produced analog signal which similar to the actual projectile projectile into the electromagnetic signal generator excitation speed measuring device, to simulate the real projectile muzzle through velocity measuring device through. In the target distance calibration, this paper use the image measurement method. Also, measuring equipment is selected. Besides, surface correction, image enhancement, filtering of noise preprocessing are used to the image. The improved Canny edge detection algorithm is used to extract the edge image of the coil, and the target distance is calculated.Finally, the test of the projectile signal simulator and the target distance measurement system are carried out. The error of the projectile signal simulator is in the range of 0.05μs, and the error of the target distance measuring device is in the range of 0.05 mm, which can meet the requirement of calibration.