To deal with the uncertainties of the particle filter of the motion model

an improved particle filter EMPF (expectation-maximization particle filter) is proposed. The target states could be estimated more accurately by combining the EM and the PF algorithms

in which the parameters of the motion model are estimated and later confirmed by the EM algorithm. Thus the target states could be estimated more accurately. And the experiment results show that when the target was turning

the algorithm can improve the estimation of the target’s motions dramatically.