Analysis of Nonstop-and-Go Effect in Spaceborne Ultra-High-Resolution SAR

For spaceborne ultra-high-resolution Synthetic Aperture Radar (SAR) systems with resolutions at the 0.1m level, the ideal signal model based on the Stop-and-Go (SAG) assumption is insufficiently accurate. The Nonstop-and-Go (NSAG) effect introduces an azimuth-range coupled NSAG phase, leading to a degradation in image focusing quality. This paper analyzes the relationship between the time-frequency characteristics, spatial variation characteristics of the NSAG phase, and imaging task parameters. It provides the boundary condition expression for neglecting the spatial variation effect of the NSAG phase. Finally, the correctness of the proposed model and the effectiveness of the method are verified through simulation experiments.