Zheng Jing-bo①② Song Hong-jun① Shang Xiu-qin①② Wu Yong①②
①(Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China) ②(Graduate University of Chinese Academy of Sciences, Beijing 100039, China)
Abstract:In this paper, the Doppler centroid frequency and the Doppler frequency rate formulas of spaceborne SAR with arbitrary orbit altitude are derived, which provides an effective method for Doppler properties study of MEO SAR and HEO SAR. Based on these formulas, the relation of Doppler centroid frequency between GEO SAR and LEO SAR is analyzed. The change of spaceborne SAR Doppler frequency rate with the orbit altitude, as well as the influence of earth rotation on the Doppler frequency rate of LEO SAR and that of GEO SAR are studied. The properties of Doppler centroid frequency and Doppler frequency rate of GEO SAR is discussed in detail. The validities of formulas and the analysis of Doppler properties are demonstrated by the numeric simulations.