Research On Real-time Aerodynamic Parameter Identification And Ballistic Reconstruction Of Ballistic Correction Projectile

In order to accurately reconstruct the follow-up ballistic and calculate ballistic deviation according to a section of measured ballistic parameters of the projectile, then achieve the purpose of ballistic correction, the ballistic model establishment, real-time aerodynamic parameter identification and ballistic reconstruction were researched on the background of ballistic correction projectile’s impact point prediction.Based on the flight principles of ballistic correction projectile, a 5 degrees of freedom (DOF) model was established for real-time aerodynamic parameter identification. The Jacobi matrix was deduced based on this model. This model could be used on a part of ballistic ballistic parameters filter, identifying the real drag and lift coincidence coefficient of projectile, and accurately reconstructing the follow-up ballistic of projectile, thus predicting the impact point. And more than that, this model omit the height frequency fast circular motion, therefore it was indicated by theory and numerical calculation that the range and lateral calculated by 5 DOF model was nearly equaled with those calculated by 6 DOF model while the computation speed of 5 DOF model was tenfold faster than that of 6 DOF model, which was very suitable for real-time ballistic calculation of projectile. The hybrid extended Kalman filter and the spherical unscented Kalman filter were selected to identify the aerodynamic parameters using the real measurement ballistic parameters. The numerical calculation results show that both of those two methods can eliminate the noise of measuring ballistic parameters effectively, and the variance of ballistic coordinate, drag and lift coincidence coefficients converge quickly. Comparing the aerodynamic parameter identification results of those two methods, it shows that the spherical unscented Kalman filter’s precision of aerodynamic parameter identification is higher, and the speed of converging is faster.On the condition of the same measuring error, the impact point precision of reconstructed ballistic was related to the sampling interval and sampling time. Considering the real-time calculation of large caliber ballistic correction projectile, the sampling interval should be selected within the range of 60ms to 100ms and the sampling time should better rung from 10s to 12s when choosing the hybrid extended Kalman filter; the sampling interval should be selected within the range of 60ms to 100ms and the sampling time should better rung from 6s to 8s when choosing the spherical unscented Kalman filter. The work here, which is proved effective and reasonable by the results of simulation and experiment, can provide the theory and numerical analysis basis for practical engineering application.