A Novel Anti-repeat Jamming Approach for Frequency Modulation Fuze

摘要

A frequency modulation (FM) radio fuze electronic counter countermeasure (ECCM) scheme is proposed in this paper to encounter the DRFM (digital radio frequency memory) repeat jamming which has posed a serious threat to the FM fuze. This scheme consists of pulse diversity and antijamming signal processing techniques in fractional Fourier domain (FFD). The pulse diversity is achieved through slope varying chirp signals which has stationary bandwidth but varied pulse duration at each pulse repetition interval. The antijamming signal processing techniques in FFD are designed for two different situations. On one hand, a repeat jamming suppression method based on twice FRFTs and notch filter in FFD is presented, considering that the jamming signal and the target echo signal make up the fuze's received signal together. On the other hand, if the jamming signal and the target echo signal exist in the fuze's received signal at different times, a signal identification method is presented to distinguish the jamming signal and the target echo signal. The received signal's FRFTs with different transformation angles have different amplitude and bandwidth performances, and these differences are utilized by this identification method. At last, formula derivations and simulation results validate this proposed ECCM scheme.