Waveform Agility in Intraplus–Interpulse Frequency and PRF for Antijamming and Coherent Processing

Interrupted sampling jamming (ISJ) and cross-pulse repeater deception jamming (CRDJ) have the same characteristics as the transmitted signal, which poses a serious threat to moving target detection. Frequency and pulse repetition frequency (PRF) agile waveforms enhance radar’s immunity to jamming. However, existing intrapulse frequency agile waveforms against ISJ suffer from high target energy loss. Furthermore, phase fluctuations from frequency and PRF agility cause incoherent echo, making range cell migration (RCM) correction difficult for moving target detection and reducing signal-to-noise ratio gain. In this article, an intraplus–interpulse frequency and PRF agile waveform is designed to resist the compound jamming of ISJ and CRDJ and achieve coherent processing. On the one hand, an intrapulse frequency agile waveform optimization method is proposed based on the ambiguity function and mismatch filters, which can reduce high-range grating lobes and target energy loss, and effectively suppress ISJ. On the other hand, the frequency and PRF are designed to satisfy the signal coherence constraints. Therefore, the target velocity can be estimated by the minimum image entropy method, which is used to compensate for the RCM. Finally, the modified nonuniform discrete Fourier transform is proposed to realize a coherent accumulation of the proposed waveform. A series of simulation experiments are used to verify the effectiveness of the proposed waveform and processing method.