基于椭圆轨道的Geo-SAR精确多普勒参数解析计算方法

Accurate Doppler Parameters Estimation of Geo-SAR Based on Elliptical Orbit

该文综合考虑了轨道偏心率、地球扁率和地球自转三方面的因素,推导得出高精度星载SAR多普勒中心频率和多普勒调频率解析式。鉴于2维姿态导引对于Geo-SAR的必要性,进一步分析了姿态导引后和零姿态导引两种情况下的多普勒参数,为Geo-SAR的多普勒参数计算提供了实用且有效的方法。该文得到的多普勒参数解析计算式适用于任意轨道高度和任意姿态的星载SAR,且具备很高的精度。基于该结论,研究了运行于椭圆轨道的Geo-SAR多普勒中心和多普勒调频率特性。

In this paper, three aspects which are the orbital eccentricity, the ellipsoidal earth model and the Earth＇s self-rotation are considered to calculate the accurate values of Doppler centroid and Doppler FM rate of spaceborne SAR. Since the 2-D attitude steering is necessary for Geo-SAR, this paper analyzes the Doppler parameters with and without the attitude steering respectively next. The conclusions are proved as the effective approach with high practicality for the Doppler parameter estimation of Geo-SAR. The analytical expressions of Doppler can be used for the spaceborne SAR at any orbital altitude with any space resolution, and the accuracy is high. Based on the conclusion, the Doppler centroid and Doppler FM rate properties of Geo-SAR moving in elliptical orbit are analyzed.