模拟合成孔径雷达数据片波差的测量和胶片、波差的容限

本文介绍一种用马赫-陈德干涉系统测量模拟合成孔径雷达数据片波差的方法.该法能把两种原因产生的波差区分开来,即把通过胶片变形的波面与平面参考波面比较,求出胶片厚度不平产生的波差;把合成孔径雷达数据片的一级衍射波面与两个半径不等的参考球面波比较,分别求出由模拟装置产生的方位维和斜距维波差.本文给出一些实验结果和分析.这种方法还可以用于测量真实合成孔径雷达数据片的波差.由胶片厚度变化产生的波差可以用液体门补偿.但是,在实际中使用液体门是很繁复的,有时也没有必要.因此,我们认瑞利准则出发导出合成孔径雷达数据片胶片厚度变化产生的波差的容限,以此作为判断是否要用液体门的依据.

Measurement of wavefront aberration of simulated SAR data film and tolerance of wavefront aberration of the film

Simulated synthetic appertnre radar (SAR) data films frtce from error of the SAR operation, but there still are aberrations introduced by the both film thickness variations and Simulated apparatus. In this paper we present a method that wavefront aberrations of simulated SAR data film can be measured by Mach-Zehnder interferometer. The method can be used separately for measuring the wavefront aberrations introduced by two different reasons. The wavefront aberration introduced by the film thickness variations is measured as compared the wavefront through the film with the reference plane wavefront. And as compared separately the diffraction wavefront from the film with two reference spherical wavefronts of different radii we obtained separately the azimuth wavefront aberration and the range wavefront aberration introduced by the simulated apparatus. In this paper some experimental results and analyses are presented. The method is also suitable for measuring wavefront aberrations of true SAR data film. The wavefront aberration introduced by the film thickness variations may be removed by a liquid gate. A tolerance of the wavefront aberrrtion introduced by the film thickness variations is deduced from the Rayleish criterion. From the tolerance we can judge whether or not the liquid gate is necessary.