Notch Filter Analysis and Its Application in Passive Coherent Location Radar (in English)
Li Ji-chuan*①② Lu Xiao-de① Xiang Mao-sheng① Yang Peng-cheng①②
①(Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China) ②(University of Chinese Academy of Sciences, Beijing 100049, China)
The Normalized Least-Mean-Squares (NLMS) algorithm is widely used to cancel the direct and multiple path interferences in Passive Coherent Location (PCL) radar systems. This study proposes that the interference cancelation using the NLMS algorithm and the calculation of the radar Cross Ambiguity Function (CAF) can be modeled as a notch filter, with the notch located at zero Doppler frequency in the surface of the radar CAF. The analysis shows that the notch’s width and depth are closely related to the step size of the NLMS algorithm. Subsequently, the effect of the notch in PCL radar target detection is analyzed. The results suggest that the detection performance of the PCL radar deteriorates because of the wide notch. Furthermore, the Nonuniform NLMS (NNLMS) algorithm is proposed for removing the clutter with the Doppler frequency by using notch filtering. A step-size matrix is adopted to mitigate the low Doppler frequency clutter and lower the floor of the radar CAF. With the step-size matrix, can be obtained notches of different depths and widths in different range units of the CAF, which can filter the low Doppler frequency clutter. In addition, the convergence rate of the NNLMS algorithm is better than that of the traditional NLMS algorithm. The validity of the NNLMS algorithm is verified by experimental results.
About author: Li Ji-chuan, was born in Linyi, Shandong Province, China, in 1988. He received the B.E. degree in electronics and information engineering from Ocean University of China (OUC), Tsingtao, China, in 2010. He is currently working towards the Ph.D. degree in signal processing at the Institute of Electronics, Chinese Academy of Sciences (IECAS). His main research interests are signal processing and moving target detection of passive radar. E-mail: lijichuan10@sina.com
Lu Xiao-de, was born in 1969. He received Ph.D. degree from Xi’an Jiaotong University in 1997. He is currently a research fellow with the Institute of Electronics, Chinese Academy of Sciences. He has won the first-class national scientific and technological progress award. His research interests are array signal processing and passive radar system. E-mail:Louee@mail.ie.ac.cn.
Xiang Mao-sheng was born in 1964. He received Ph.D. degree from the Institute of Remote Sensing Applications, Chinese Academy of Sciences in 1999. He is currently a research fellow with the Institute of Electronics, Chinese Academy of Sciences. He has won the first-class national scientific and technological progress award. His research interests are microwave remote sensing signal processing and InSAR system technology. E-mail:xms@mail.ie.ac.cn.
Cite this article:
Li Ji-chuan,Lu Xiao-de,Xiang Mao-sheng et al. Notch Filter Analysis and Its Application in Passive Coherent Location Radar (in English)[J]. JOURNAL OF RADARS, 2014, 3(6): 675-685.
2014, Vol. 3 
