J_2摄动对分布式卫星SAR系统测高精度影响分析

Effects of J_2 perturbation on height measurement precision of distributed SAR system

建立精确的分布式卫星SAR系统测高模型,对系统的分析和设计具有重要的意义.在考虑地球扁率的前提下,建立了一种精确的分布式卫星SAR系统测高模型,并进行了测高精度分析.同时考虑分布式卫星SAR系统在轨运行过程中受到各种摄动力的影响,为了考察在轨运行情况下系统的测高性能,以摆式构形的分布式卫星SAR系统为例,在Js摄动情况下进行测高精度的数学仿真.结果表明在考虑J2摄动情况下,随着系统运行时间的增加,摆式构形的分布式卫星SAR系统测高精度变化幅值逐渐增大.针对J2摄动对系统测高精度的影响,提出了通过提高系统基线,方位角,和干涉相位角的测量精度来保证系统正常工作的方法.

To better analyze and design the distributed SAR system, a precise height measurement model was established considering the eccentricity of the earth, and the imaging precision was analyzed. Meanwhile, considering the on-orbit distributed SAR system affected by different kinds of perturbation, a distributed SAR system with a pendulum formation was taken as an example to research the height imaging capability of the on-orbit system, and the mathematic simulation was conducted under the J2 perturbation. The results show that, under the J2 perturbation, the height imaging precision of the distributed SAR system is increasing. According the effects of the J2 perturbation, a method is presented to guarantee the operation of the distributed SAR system by improving the precision of the baseline, baseline azimuth angle and interventional angle.