Measurement Method Of Projectile Muzzle Motion Parameters Based On Geomagnetic Field

In the process of research,production and delivery of artillery and other weapons,the muzzle motion parameters of projectiles such as muzzle velocity and rotational speed are key indicators for characterizing and evaluating the performance of artillery,and are also important parameters for external guidance.Accurate measurement of muzzle parameter data under different environments and firing conditions is of great significance for reducing firing deviations,correcting ballistic trajectories,giving artillery accurate fire elements,and improving combat damage effectiveness.In order to achieve the above parameters detection,a method of measuring the muzzle motion parameters of the missile-borne test based on the geomagnetic field was studied and proposed.First,the distribution characteristics of the induced magnetic field around the ferromagnetic body tube and projectile in the geomagnetic environment were analyzed and described by combining the basic theory of geomagnetic field.After that,the motion path of the sensor during the projectile firing out of the chamber in the non-spin state was set up through finite element modeling simulation,and then the perceived magnetic field change pattern with the projectile motion was obtained.In order to make the study more comprehensive,the similarities and differences of the magnetic field signals before and after exiting the muzzle were compared for different firing conditions with different projectile angles.The characteristic points of the magnetic induction intensity mode curve on the sensor path were analyzed by using two derivatives,and the theoretical measurement method of the projectile muzzle velocity in the non-spin state was proposed based on the conclusion that there are two characteristic points of the curve.After that,the detection platform was built for simulation experiments,and the sensor was controlled to pull out the muzzle from the simulated body tube bore at the same speed for a certain distance along the axial direction of the body tube,and the change of magnetic field signal was observed to verify the basic principle of the velocity detection method.After that,based on the research conclusion that there are two characteristic points in the non-rotation state,the isotropic rifling was added inside the original body tube model to introduce the measurement method of the muzzle rotational speed and velocity of the conventional isotropic rifled artillery in the rotating state.The simulation analyzed the magnetic field distribution on the circumferential path and sensor motion path,and also used two derivative analyses for the magnetic field on the sensor motion path to obtain the projectile muzzle rotational speed according to the way of feature points,combined with circumferential features,and solved the muzzle velocity on the basis of the speed.Test data using the built platform and fundamental analysis of environmental influencing factors and application conditions were done.The results of simulation and simulation experiments show that the measurement of muzzle motion parameters can be achieved by using the geomagnetic field distribution during the projectile movement.