重力场对弹道导弹自由段落点影响的仿真分析

利用EGM96地球重力场模型,采用数值积分方法分析了重力场J2项、J4项以及扰动重力对弹道导弹自由段落点偏差的影响,讨论了积分步长的选取和重力场模型阶数的选取。仿真计算结果表明,对6000km左右自由段射程的弹道导弹,J2项引起的落点偏差最大达到15km以上;J4项引起的落点偏差最大达到60m左右;扰动重力的影响可达到数百米,为达到米级的落点精度,需考虑到30阶左右的重力场模型。

Simulated analysis of the effect of gravity field to the fall point in free flight trajectory of ballistic missile

Based on EGM96 gravity field model,the effects of J_2、J_4 and disturbing gravity to the deviation of fall points in free flight trajectory of ballistic missiles are analyzed by numerical integration,and the selection of integration steps of numerical integration and maximum degrees of gravity field model are discussed.Simulated results show that,for ballistic missiles with six thousand kilometer free flight,the largest deviation of fall points caused by J_2 can reach more than 15 km;the largest deviation of fall points caused by J_4 can reach 60m;the deviation of fall points caused by disturbing gravity varies from tens of meters to hundreds of meters.In order to get the meter accuracy,about 30 degrees in maximum gravity field model have to be considered when calculating the disturbing gravity.