The aircraft altitude relative to the illuminated region is a significant parameter for the geometric correction in squint mode synthetic aperture radar (SAR) imaging. Error in the parameter causes geometric distortion, which degrades the image quality. To circumvent this problem, a relative altitude estimator (RAE) is proposed based on the relationship between the relative aircraft altitude and the range variation of the Doppler centroid. The high performance of the RAE is investigated compared to the Cramér-Rao lower bound of the relative aircraft altitude. Finally, the effectiveness of the RAE in practical applications is verified by real data processing.Index Terms-Cramér-Rao lower bound (CRLB), doppler centroid variation, geometric correction, relative altitude estimator (RAE), squint mode SAR, synthetic aperture radar (SAR).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.