Time-frequency Analysis Techniques for Recognition and Suppression of Interrupted Sampling Repeater Jamming
ZHOU Chao LIU Quanhua* HU Cheng
(School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China)
(Key Laboratory of Embedded Real-time Information Processing Technology, Beijing 100081, China)
Abstract：Through partial intercepting and multiple forwarding of a radar transmitting signal, Digital Radio Frequency Memory (DRFM)-based Interrupted Sampling Repeater Jamming (ISRJ) possesses advantages of small size, light weight, and flexibility. Thus, DRFM-ISRJ can be equipped on targets to perform multi-point source main-lobe jamming, posing a serious threat to modern radars. In this study, a time-frequency domain recognition and suppression method was analyzed. First, the expression of pulse compression and Time-Frequency Distribution (TFD) of the jamming signal were deduced. Then, the differences of TFD between target echo and jamming signal were analyzed. On this basis, a jamming recognition program and a time-frequency domain filter to suppress the jamming were proposed. Simulation results show that the recognition rate is better than 90% when the jamming-to-noise ratio is over -3 dB for the received signal. Based on correct recognition, a signal to jamming-and-noise ratio improvement of 18 dB can be achieved using the time-frequency filter.
