**Yuan Huang, Liping Wang, Xueying Wang \* and Wei An**

College of Electronic Science, National University of Defense Technology, Changsha 410073, China; huangyuan09@nudt.edu.cn (Y.H.); wangliping17@nudt.edu.cn (L.W.); anwei@nudt.edu.cn (W.A.)

**\*** Correspondence: wang\_xueying87@126.com; Tel.: +1-354-894-9042

Received: 11 October 2019; Accepted: 22 November 2019; Published: 23 November 2019

**Abstract:** The extended target Gaussian inverse Wishart probability hypothesis density (ET-GIW-PHD) filter overestimates the number of targets under high clutter density. The reason for this is that the source of measurements cannot be determined correctly if only the number of measurements is used. To address this problem, we proposed an anti-clutter filter with hypothesis testing, we take into account the number of measurements in cells, the target state and spatial distribution of clutter to decide whether the measurements in cell are clutter. Specifically, the hypothesis testing method is adopted to determine the origination of the measurements. Then, the likelihood functions of targets and clutter are deduced based on the information mentioned above, resulting in the likelihood ratio test statistic. Next, the likelihood ratio test statistic is proved to be subject to a chi-square distribution and a threshold corresponding to the confidence coefficient is introduced and the measurements below this threshold are considered as clutter. Then the correction step of ET-GIW-PHD is revised based on hypothesis testing results. Extensive experiments have demonstrated the significant performance improvement of our proposed method.

**Keywords:** extended target; target tracking; PHD filter; high clutter density
