弹道中段目标进动周期估计的改进自相关法

自相关法可用于估计弹道中段雷达目标的进动周期,它需要预先给出进动周期的上下限。进动周期下限可能远小于真实进动周期,此时自相关法的估计性能将严重下降。定义了自相关函数(ACF)的凸包,在此基础上提出了一种改进的自相关法。首先求出ACF和其凸包的差函数,然后搜索差函数的最大值,从而得到进动周期的估计值。理论分析和仿真结果表明:当进动周期下限和真实进动周期相差不大时,该方法的估计性能接近自相关法;当进动周期下限远小于真实进动周期时,该方法仍然具有良好的估计性能;由于进动周期的上下限之比通常大于2,因此该方法的计算量比自相关法增大的倍数小于1.4;同时它对先验信息的要求非常宽松。因此该方法具有广泛的适用性。

Improved Autocorrelation Method for Precession Period Estimation of Ballistic Target in Midcourse

The autocorrelation method can be used to estimate the precession period of a ballistic radar target in midcourse, for which it is necessary that the upper and lower bounds of the precession period be given in advance. However, the lower bound of the precession period provided may be far less than the true precession period, which will seriously degrade the estimation performance. An improved autocorrelation method is proposed by defining the convex hull of the autocorrelation function(ACF). The difference function between the ACF and the convex hull is obtained, and then the precession period is estimated by searching for the maximum value of the difference function. The theoretical analysis ancl simulation results show that the estimation performance of the proposed method is close to the autocorrelation method when the lower bound is not far less than the true precession period. When the lower bound is far less than the true precession period, the proposed method still has good estimation performance. Usually the ratio of the upper bound to the lower bound is larger than 2, resulting in the computational burden of the proposed method less than 1.4 times of that of the autocorrelation method. Also it is very easy to meet the prior information requirement for the proposed method. Therefore the proposed method can be used widely.