A Mainlobe-Safe Modular Formation Optimization Method for Large-Scale MuSAR with Joint ATI/XTI Baseline Requirements

Multistatic synthetic aperture radar (MuSAR) formations with a large number of satellites can provide diverse along-track interferometric (ATI) and cross-track interferometric (XTI) baselines, but increasing formation size introduces strong coupling among baseline performance, intersatellite mainlobe safety, minimum separation, and synchronization-link availability. This paper proposes a Mainlobe-Safe Modular Formation Optimization (MSMFO) method for large-scale MuSAR with joint ATI/XTI baseline requirements. A parameterized relative-motion model and a unified evaluation framework are employed to jointly account for baseline compliance, synchronization-link availability, mainlobe conflicts, and intersatellite separation, with mainlobe conflicts and minimum separation imposed as hard constraints. A Multi-Strategy Cooperative Evolution (MSCE) framework combines complementary global search strategies with local refinement, while a two-level center-layer/module-layer architecture enables scalable formation design. Numerical results show that a six-satellite module achieves XTI and ATI baseline compliance rates of 89.17% each, with 99.98% synchronization-link availability and no safety violations. Compared with the best feasible classical formation, the lower of the two baseline compliance rates is improved by 10.89 percentage points. A controlled study spanning 8–96 satellites maintains consistent module-layer performance, high center-layer compliance, 100% joint availability, and zero global safety violations, providing evidence of modular scalability.