中文摘要：

针对再入阶段弹道目标的跟踪问题,提出一种新的自适应滤波算法,即强跟踪有限差分扩展卡尔曼滤波（STFDEKF）算法,用于非线性系统的目标跟踪。该方法使用Sterling内插公式进行多项式的近似,从而实现对非线性函数的近似,避免了非线性函数的求导运算;并且算法中引入强跟踪的因子来修正先验的协方差矩阵。新算法改进了跟踪精度,扩大了应用范围,增强了滤波收敛性。仿真实验将新算法与扩展卡尔曼滤波器（EKF）、有限差分扩展卡尔曼滤波器（FDEKF）进行了比较,结果表明,STFDEKF在跟踪精度和滤波可靠性上均优于EKF和FDEKF,但其计算复杂性更大。得出结论,STFDEKF是个很有效的非线性滤波算法。

英文摘要：

This paper studies the problem of tracking a ballistic target in the reentry phase.It proposes an adaptive algorithm, Strong Tracking Finite-Difference Extended Kalman Filter（STFDEKF）,for ballistic target tracking in reentry.This method uses polynomial approximations obtained with a Sterling interpolation formula to approximate the derivative of the nonlinear function,and uses strong tracking factors to modify the prior covariance matrix.The proposed algorithm improves the tracking accuracy, enlarges the applied area and enhances the filtering convergence.It compares the performance of the proposed algorithm with that of the Extended Kalman Filter（EKF） and the Finite-Difference Extended Kalman Filter（FDEKF） using a Monte Carlo simulation.The simulation results show that STFDEKF outperforms EKF and FDEKF in terms of tracking accuracy, filter credibility and robustness against the sensitivity to filter initial condition.It concludes that the STFDEKF is an effective algorithm for the ballistic target tracking problem being studied.