A Coherent Integration Method for Time-Varying Phase Modulation Target Based on a Short-Pulse MIMO Radar

The time-varying phase modulation (TVPM) of a target can impose dynamic phase changes on incident electromagnetic waves, altering radar echo characteristics. This phenomenon renders traditional radar coherent processing ineffective, leading to degraded radar signal processing performance. To address the challenge posed by random phase modulation introduced by TVPM, this work proposes a coherent integration method based on a short-pulse multiple-input–multiple-output (MIMO) radar. First, a short-pulse MIMO radar system based on dual-channel frequency diversity is designed. This system not only mitigates fast-time random phase modulation but also enhances the flexibility of phase compensation using multichannel data. Furthermore, by integrating multichannel information and considering the peak sidelobe ratio and integrated sidelobe ratio of the coherent integration output, a multichannel slow-time domain joint phase compensation optimization model is proposed. In addition, to address constraints in the fast-time domain, this article introduces a fast–slow-time domain joint phase compensation optimization model. Given that these two optimization models involve discrete variables and multiple optimization objectives, this article employs the nondominated sorting genetic algorithm II (NSGA-II) to solve the optimization problems. Furthermore, considering the tendency of the NSGA-II to converge to local optima and the need for addressing multiobjective optimization, a compensation signal-to-noise ratio enhancement optimization model based on min–max optimization is introduced to improve the performance of the coherent integration. The alternating direction method of multipliers framework is employed to effectively solve this problem. Finally, the effectiveness of the proposed method is validated through simulation and practical experiments.