低重复频率下的目标速度估计算法研究

A Study on Target Velocity Estimation under Low PRF Condition

研究了低重复频率下的目标速度估计问题,提出一种利用相邻回波脉冲的互相关函数进行测速的方法。首先利用每个脉冲起始频率与到达时间的线性关系,在时域上把回波脉冲串对准,使回波达到相参条件。然后对相参之后的相邻脉冲进行互相关运算,估计互相关函数的频率并根据该频率与目标速度的关系得到速度估计值。取所有估计值的均值作为目标速度的最终估计。该方法的估计精度小于无模糊速度,可以用于解速度模糊或作为最大似然估计迭代的初始值。

The estimation of target velocity under low pulse repetition frequency（PRF） is investigated in this paper and a novel tar-get velocity estimator,which utilizes the cross-correlation function of the adjacent echo returns,is presented.Firstly,the echo re-turns are aligned in time-domain according to the linear relationship between the initial frequency and the time-of-arrival（TOA）,thus the echo pulse train is cohered.The cross-correlation function of the adjacent pulses of the cohered pulse train is computed and its frequency is estimated.The estimate of the target velocity can be obtained according to the relationship between the frequen-cy and the velocity.The final velocity estimate is obtained by averaging all of the estimates.Simulations show that the root mean square error of the estimator is smaller than the unambiguous speed and can be used to solve speed ambiguity or to be the initial value of the maximum likelihood iteration algorithm.