Anti-jamming Method of Ultra-wideband Fuze Based on Backward Variable Distance Gate Detection

To address the problem that the active interference in the signal band may cause the false activation of ultra-wideband (UWB) fuze, an anti-interference method based on backward variable distance gate detection is proposed by exploiting the time-space irreversibility during the fuze flight. A "discovery-verification-confirmation" detection model is established by using the relationship between the transmission and reception timing of UWB fuze and the distance gate. This model enables the discovery, confirmation and verification of target signals through multiple timing-controlled changes in the position of distance gate. Meanwhile, an adaptive sliding-window fast Fourier transform (FFT) is used to extract the velocity information from echo signals, enabling the adaptive adjustment of the time windows for different detection states. A probabilistic starting model of UWB fuze is then established, and the normal activation probability of UWB fuze under interference-free conditions is theoretically derived. Furthermore, an interference probability model is established based on the failure mechanism of UWB fuzes under jamming conditions, and the false starting probability under swept-frequency jamming is analytically deduced. The mathematical simulation and starting probability analysis are carried out for the proposed method. Compared with the traditional single detection method, the variable distance gate detection method can significantly enhance the anti-jamming capability of UWB fuze while maintaining the normal detection performance. Finally, the swept-frequency jamming experiments and low-speed target rendezvous test prove that the proposed method is effective.