Research On Velocity Measurement Technology Of Projectile Muzzle

With the development of modern weapons precision strike, the velocity of projectile muzzle as an important initial parameter in exterior ballistic solution of inertial navigation unit, the parameter precision and real-time measurement, which directly affect the precision solver for exterior ballistics and increase the hit rate of the projectile. This paper describes a real-time measurement method of velocity of projectile muzzle by combining coil target with magneto-resistive sensors. Using two sets fixed and measurable distance electrified coils to product a certain size magnetic field which embedded in muzzle brake. The flight time can be measured when projectile flight to two sets coils, and real-time calculated the velocity of projectile muzzle by installed on the projectile of magnetic-resistance sensor and the signal collection and processing circuit. The measuring system has many adventages, such as small volume, low price, operating easily, real-time well.Analysis of bad test environment of test system, the error sources that be produced by methods of measurement errors and obtaining the maximum relative error0.197%by theoretical calculations.The paper that is based on a100bombs, using the ANSYS finite element analyzes and simulates the gun system of the size of the magnetic field intensity and magnetic vector distribution. Building a mathematical model of barrel and coils, simulation magnetic shielding size of barrel, according to the size of magnetic field of magnetic shielding of barrel and turns, layers of coil to get the voltage provided by two sets of coils energized. Simulating magnetic vector distribution and the size of the magnetic field intensity of two coils energized, which provides the basis for selection of magneto-resistive sensors, extraction and solution of signal acquisition and feasibility of the system.For conventional ammunition requires small volume, high anti-overload, high dynamic requirements. Selecting the HMC1043magneto-resistive sensor which has small size, high sensitivity, STM32F405RG controller is the main components of the system which is possesses of small size, high integration and high efficiency, and compiles the corresponding software program to control and solve velocity of projectile muzzle.Finally, the paper uses ground experiment to evaluate the system performance of anti-overload and real-time to measure speed. Using ANSYS simulation system structure changes of displacement offset and stress in the materials allowed range in the10000g impact action, then the experiment verification system of anti-overload capability by use of machete hammer. It uses100mm air cannon to verify the capability of real-time measure speed in the system, at the same time, compared to the precision of measure system by uses of Laser velocimetry to measured initial velocity of projectile muzzle, both of measure velocity error in0.202%, close to the theoretical analysis of the relative velocity error. Verity the correctness and operability of the design system.