ENVISAT/ASAR多角度干涉雷达数据山区DEM生成及精度分析

在地形起伏较大的山区用干涉SAR生成DEM时,合适的入射角是获取高精度DEM的重要参数之一.本文基于ENVISAT/ASAR多角度干涉雷达数据,SRTM 90米分辨率的DEM以及1:5万的数字化DEM数据,从定性和定量的角度比较和分析了干涉SAR在获取山区DEM时,入射角对DEM精度的具体影响.结果表明:对于ASAR的多入射角干涉雷达数据,在不同入射角条件下由于雷达叠掩和透视收缩的影响,获取的DEM精度差别很大,入射角带来的影响相当显著,比如IS2和IS4角度得到的DEM的精度差超过了6米.因此,在山区干涉SAR地形成图时,必须对入射角的大小进行严格的选择.     

Cost Effective Frequency Ranges For Multi-Beam Dishes, Cylinders, Aperture Arrays, and Hybrids

Five out of six Square Kilometre Array (SKA) science programs need extensive surveys at frequencies below 1.4 GHz and only four need high-frequency observations. The latter ones drive to expensive high surface accuracy collecting area, while the former ask for multi-beam receiver systems and extensive post correlation processing. In this paper, we analyze the system cost of a SKA when the field-of-view (Fov) is extended from 1 deg² at 1.4 GHz to 200 deg² at 0.7 GHz for three different antenna concepts. We start our analysis by discussing the fundamental limitations and cost issues of wide-band focal plane arrays (FPA) in dishes and cylinders and of wide-band receptors in aperture arrays. We will show that a hybrid SKA in three different antenna technologies will give the highest effective sensitivity for all six key science programs.