ABSTRACT

A method of correcting the slant-range error of the space-borne interferometric synthetic aperture radar (InSAR) system aboard the TH-2 satellites is proposed. First, we calculate the tropospheric-delay using the third-order fractional mapping-function method, and we calculate the ionospheric-delay using the ray-tracing method. The calculations show that the atmospheric-delays for the TH-2 ranges from 2.23 m to 3.08 m in four areas. Next, From the channel-delay at corner-reflectors (CRs), we determine the average channel-delay to be 4.02 m from data-processing results for 22 scenes. Finally, we use the field data obtained by TH-2 to evaluate the effect of the slant-range correction. After correcting for the slant-range error, the accuracy of image-point coordinate prediction in the range direction is improved from about 7 pixels to less than one pixel. The ground-point positioning accuracy in elevation is also improved by about 4.65 m, and the plane accuracy approaches the elevation accuracy. The method proposed in this paper has been used to correct the slant-range error of TH-2, and the expected results have been achieved.

摘要

提出了一种校正TH-2卫星星载干涉合成孔径雷达（InSAR）系统斜距误差的方法。首先，我们使用三阶分数映射函数方法来计算对流层延迟，并使用射线追踪法来计算电离层延迟。计算表明，TH-2在四个区域的大气延迟范围从2.23 m至3.08 m。接下来，根据22个场景的数据处理结果，根据角反射器（CR）的通道延迟，确定平均通道延迟为4.02 m。最后，我们使用TH-2获得的现场数据来评估倾斜范围校正的效果。校正了倾斜范围误差后，范围方向上的图像点坐标预测的精度从大约7个像素提高到小于1个像素。高程中的地面点定位精度也提高了约4.65 m，并且平面精度接近高程精度。本文提出的方法已被用于校正TH-2的斜距误差，并取得了预期的结果。