Improved Interrupted Sampling Repeater Jamming based on DRFM

Abstract

Interrupted Sampling Repeater Jamming (ISRJ) can be implemented easily based on Digital Radio Frequency Memory (DRFM) technique. An improved method is presented in this paper which has all advantages of traditional ISRJ. Furthermore, the improved ISRJ obtains a train of false targets that precede the true one. The radar radio signal is downshifted and sampled by receive-transmit time-sharing antenna and then stored to digital memory. Its retransmitting signal reserves the coherent property so that a large number of false targets will be achieved after matched filter of the pulse compression radar. The principal and quantitative relation between the false targets and the true one is deduced and analyzed. Simulation illustrates that the improved ISRJ method obtains several false targets ahead of the true one and the amplitude of the main false target decrease compared with the traditional method. The amplitude decrease can be remedied by enhancing the power of transmitting antenna. Imaging results with improved ISRJ method to real SAR raw are shown at last.

Countermeasure for Interrupted-sampling Repeater Jamming based on Fractional Fourier Transformation

“…According to the LFM waveform data and the receiving window width, the optimum transform order is calculated. 1 2…”

“…With the development of LFM interference method, jammers with digital radio frequency memory (DRFM) can accurately reproduce the received radar signals and simulate them, resulting in coherent jamming effect, especially for LFM signals. The development and perfection of interrupted-sampling repeater jamming (ISRJ) [1], which is flexible and has diverse forms, can form several false targets [2] to deceive radars, as well as creating the effect of noise suppression to a certain extent. With the flexibly change of repeating and modulation method, interference effect is improving, which has posed a serious threat to the tracking radar, so it is urgent to seek a way to counter this type of interference [3].…”

A Novel Radar Waveform Design for Anti-Interrupted Sampling Repeater Jamming via Time-Frequency Random Coded Method

“…As a classic jamming type derived from digital radio frequency memory (DRFM) [1][2][3], the ISRJ is more likely to generate multiple false targets after pulse compression because of its strong correlation with radar signals. The new ISRJ patterns include frequency shift modulation [4], smart noise modulation [5], interrupted sampling signal modulation [6][7][8], etc. However, compared with interference technology, the research of anti-ISRJ interference technology [9] is relatively insufficient, most of which are aimed at radar echo signals, and anti-jamming processing is performed in the signal processing stage, such as filter design methods.…”

A Novel Interference Suppression Method for Interrupted Sampling Repeater Jamming Based on Singular Spectrum Entropy Function

“…As a classic jamming derived from DRFM, the interrupted sampling repeater jamming (ISRJ) is highly correlated to the radar signal which makes it prone to generate multiple false targets after pulse compression [1]. Meanwhile, ISRJ has become more and more ubiquitous with the developed sampling, storage and repeater hardware in DRFM and therefore a great number of the improved interference algorithms are proposed based on related researches, which includes interrupted sampling and direct repeater jamming (ISDRJ), interrupted sampling and periodic repeater jamming (ISPRJ), interrupted sampling and cyclic repeater jamming (ISCRJ) [2,3,4,5], and new jamming patterns based on ISRJ such as frequency shift modulation [6], smart noise modulation [7], and interrupted sampling signal modulation [8,9,10]. ISDRJ, ISPRJ and ISCRJ are distinguished from each other by different repeater strategies which can generate different kinds of false targets after pulse compression.…”