Two-sided Long Baseline Radargrammetry from Ascending Descending Orbits with Application to Mapping Post-seismic Topography in the West Sichuan Foreland Basin

合成的孔雷达(SAR ) stereo-radargrammetry 的片面上升或下降限制了由于短空间基线(100 km ) 和小交叉角度的地志的印射的精确性。以便改进从卫星转菠的 SAR radargrammetry 产生数字举起模型(DEM ) 的表演和可靠性，从与长空间的基线(1000 km ) 的几何配置登上并且下降轨道的联合的两方面的 stereo-radargrammetry 的探索在这研究被进行。在到放方程的地球表面和 Doppler 的 SAR 传感器之间的观点范围几何学被采用建立实体镜的交叉模型。两方面的 radargrammetric 举起的测量无常根据在输入 SAR 图象之间的同类的点的雷达视差被估计。ALOS/PALSAR (先进土地观察卫星 / 阶段数组类型 L 乐队合成的孔雷达) 的二立体声对有轨道的分离的获得在有在西南的中国卷地形学的西方四川低岬盆上的几乎 1080 km 在学习被采用在撞击了这个区域的 2008 Wenchuan 地震以后获得新地面数据。对两方面的 radargrammetric DEM 的量的精确性评价与参考被执行回答 GPS 观察。试验性的结果证明没有使用的地面控制点(GCP ) ，举起精确性到达 5.5 m，并且精确性是进一步的改善了到 1.5 m，一仅仅 GPS GCP 用作最少的限制。理论分析和严峻的结果证明从上升并且下降的轨道的两方面的长基线 SAR radargrammetry 能是为大区域、高的精确性的一种很有希望的技术选择地志的印射。

One-sided ascending or descending Synthetic Aperture Radar（SAR） stereoradargrammetry has limited accuracy of topographic mapping due to the short spatial baseline（-100 km） and small intersection angle. In order to improve the performance and reliability of generating digital elevation model（DEM） from spaceborne SAR radargrammetry, an exploration of two-sided stereoradargrammetry from the combination of ascending and descending orbits with geometric configuration of long spatial baseline（-1000 km） was conducted in this study. The slant-range geometry between SAR sensors to the earth surface and the Doppler positioning equations were employed to establish the stereoscopic intersection model. The measurement uncertainty of two-sided radargrammetric elevation was estimated on the basis of radar parallax of homogeneous points between input SAR images. Two stereo-pairs of ALOS/PALSAR（Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar） acquisitions with the orbital separation almost 1080 km over the west Sichuan foreland basin with rolling topography in southwestern China were employed in the study to obtain the up-to-date terrain data after the 2008 Wenchuan earthquake that hit this area. Thequantitative accuracy assessment of two-sided radargrammetric DEM was performed with reference to field GPS observations. The experimental results show that the elevation accuracy reaches 5.5 m without ground control points（GCPs） used, and the accuracy is further improved to 1.5 m with only one GPS GCP used as the least constraint. The theoretical analysis and testing results demonstrate that the twosided long baseline SAR radargrammetry from the ascending and descending orbits can be a very promising technical alternative for large-area and high accuracy topographic mapping.