“Stop-and-go” error analysis of geosynchronous SAR

Abstract

In this paper, the slant range error introduced by the “stop-and-go” assumption is analyzed in detail. Owing to the high orbit and long synthetic aperture time of geosynchronous SAR (Geo-SAR), the slant range error introduced by the “stop-and-go” assumption should be considered. In addition, an accurate signal propagation delay time equation of Geo-SAR based on circle orbit is presented, and the error of the “stop-andgo” assumption is demonstrated by simulation. An “equivalent position” model is proposed and validated by simulation. The error of various powers of “stop-and-go” slant range is analyzed using Legendre orthogonal series expansion. The limitation of the stop-and-so assumption is proved by point target simulation.

创新点

由于地球同步轨道SAR的超高轨道高度和超长合成孔径时间,使得低轨道SAR的成像方法不能完全适用于地球同步轨道SAR。本文分析了传统“stop-and-go”假设所引起的斜距误差对地球同步轨道SAR成像的影响,并提出了一种正圆轨道下的成像几何模型。基于此模型,找到了能用于成像的等效中点位置。利用legendre 正交级数展开,分析了"stop-and-go"假设所引起的斜距误差的具体形式。最后,通过点目标仿真,验证了"stop-and-go"假设的局限性和本文提出的模型的有效性。