확장 오메가-케이 알고리즘을 기반한 곡선기하에서의 초고해상도 SAR 영상생성 연구

Abstract

Conventional algorithms based on synthetic aperture radar(SAR) mainly assume that slant-range variations between the radar and target are represented by a hyperbolic-range-equation(HRE) model. However, this HRE model assumption is not valid for spaceborne SAR systems owing to their curved geometry; this significantly degrades performance of the conventional SAR-based algorithms, especially when requiring ultra-high resolution. Therefore, in this paper, we propose a SAR processing chain for curved-orbit geometry using the extended omega-K algorithm(EOKA). In the proposed method, orbit compensation is first applied to mitigate the effect of the HRE error, after which EOKA is performed. Next, azimuth compression is performed based on the polynomial range model, which compensates for the defocusing of SAR images caused by the HRE model error. Through simulations, we verified that the proposed method could provide focused SAR images for curved-orbit and ultra-high resolution cases.