Processing of Hypersonic Glide Vehicle-Borne SAR Data With Spiral Trajectory

Hypersonic glide vehicle usually flies in a spiral trajectory to avoid being detected, reconnoitered, or jammed. However, due to its complex flight characteristics, the hypersonic glide vehicle-borne (HGV) synthetic aperture radar (SAR) faces several new challenges, including the complicated geometric model, serious cross-coupling, and significant spatial variation. To address these issues, a precise range model with large maneuvering parameters is first derived on the basis of the kinematic features, indicating that the signal properties change greatly. Then, a novel nonuniform fast Fourier transform (NUFFT)-based approach performed in the 2-D frequency domain is proposed. The cross-coupling terms are decoupled according to Lagrange mean value and the spatial variations are eliminated by 2-D NUFFT operation, which has a high depth-of-focusing and is more effective for HGV SAR with spiral trajectory. The effectiveness of the proposed approach is substantiated through a series of computer simulations and semi-real data experiments.