Initial Phase Coding With Two-Dimensional Local Low Sidelobes for Suppression of Active Forwarding Signals

The electromagnetic environment in modern battlefields is highly complex, particularly due to active forwarding signals based on digital radio frequency memory (DRFM), which significantly affects radar performance. Active forwarding signals generate jammers in the radar receiver.A jammer with a negative range offset needs to reach the radar with an inter-pulse delay. In addition, the target may also introduce range ambiguity in some cases. This paper establishes a general signal model for inter-pulse initial phase coding and proposes a two-dimensional local low sidelobe initial phase coding algorithm. This algorithm optimizes both the slow-time and Doppler dimensions to make local low sidelobes in both dimensional. The designed initial phase sequence ensures the Doppler resolution of the target while exhibiting locally low sidelobes in the Doppler responses of jammers.Simulation results demonstrate that this algorithm effectively enhances the radar's resistance to jammers and improves target detection performance. Furthermore, it operates independently of prior detection information and maintains low computational complexity.