Random Modulation-Based Low-Sampling-Rate Radio Proximity Fuze Design and Anti-Repeater Jamming Method

Continuous triangular wave frequency modulation fuze is susceptible to interception by jammers due to its predictable waveform characteristics, exhibiting significant vulnerabilities to anti-jamming capabilities. Additionally, traditional wideband sampling methods face challenges in terms of high hardware costs and data processing burdens. To enhance signal concealment and environmental adaptability, this paper proposes a cooperative scheme combining random modulation with narrowband sampling, constrained by velocity information. By constructing a time-frequency disturbance coupling model, a pseudo-random sequence is used to drive the pseudo-random fluctuations of the triangular wave's time width and modulation rate. Meanwhile, the narrowband sampling window is optimized based on velocity estimation, resulting in a novel modulation architecture that combines signal unpredictability with hardware implementability. At the receiver end, the correct demodulation of the target signal is achieved using a shared random seed, and a spectrum peak normalization suppression method is introduced to enhance the signal-to-noise ratio characteristics of the difference frequency signal. Simulation results demonstrate that, while maintaining a relative error of only 1.35% in speed easurement accuracy, the system sampling rate is reduced to below 400MHz, and the out-of-band spurious power is reduced by 43.5dB, providing an engineering-implementable solution for low-cost anti-jamming fuze design.