极化干涉雷达遥感机制及作用

极化干涉SAR是目前雷达遥感的前沿领域，它是集极化SAR和干涉SAR于一体的新型对地观测技术。通过对极化干涉的基本原理和物理机制，极化干涉SAR的数据处理及与常规干涉SAR数据处理的区别，以及极化干涉SAR当前的几个热点应用研究领域进行了阐述，对极化干涉SAR存在的问题也进行了讨论。     

干旱—半干旱地区地表特征探测的成像雷达干涉测量方法与模型

从估测干涉测量雷达数据相关性出发，通过利用欧洲资源卫星1号和2号获取的重轨干涉测量雷达数据，开展新疆喀什试验区地表土地类型的识别与分类，区分和识别出裸土，盐碱地，灌丛，裸岩/戈壁，沼泽和水体6类土地类型。并对不同土地类型的后向散射特性和相关性进行定量分析。探讨干涉测量数据相关性干旱-半干旱地区地表特征的关系，从而建立了干旱-半干旱地区地表变化的干涉测量时相关模型。为干旱-半干旱地区利用干涉测量数据进行地表变化监测提供理论依据。     

组合VLBI和SLR数据估计的全球板块运动参数

本文组合应用ＶＬＢＩ和ＳＬＲ数据导出了一个完全基于空间技术实测数据的现时板块运动模型，称为ＳＧＰＭＭ１。ＳＧＰＭＭ１与地学板块运动模型ＮＵＶＥＬ－１的比较指出：空间大地测量数据估计的板块运动总体上与地学估计值一致。经过地磁极倒转时间尺度修正，并考虑到冰斯后地壳回弹的影响，空间大地测量数据估计的北美，欧亚和澳大利亚板块之间的相对运动速率与地学估计值有极好的一致，但太平洋板块相对于北美、欧亚和澳大利亚     

基于VLBI、SLR和GPS实测数据的现时板块运动模型

采用空间大地测量技术 (VL BI、 SLR、 GPS)实测板块运动的最新数据 ,导出了全球 7个主要板块 (欧亚、北美、太平洋、澳大利亚、非洲、南美、南极板块 )之间的相对运动欧拉矢量 ,建立了一个完全基于空间大地测量观测的现时板块运动模型 ,称为 SGPMM2。与地学板块运动模型 NUVEL-1 A相比两者基本一致 ,说明最近 3百万年内全球板块运动总体上是稳定的。作者还首次导出了南中国板块相对于欧亚板块的相对运动欧拉矢量 (2 0 .5°S,67.2°W,0 .3 0 0°/ Ma)。与 Armijo等 (1 989)根据欧亚板块内北西藏块体与周围块体的断层走向和滑动速率估计的北西藏块体相对于欧亚板块的欧拉矢量 (1 7.0°S,61 .4°W,0 .45 8°/Ma)相比 ,两者运动方向一致 ,但南中国板块的运动速率稍小。作为对印度板块高速插入欧亚板块之下的响应 ,这个结果证实了南中国板块受西藏块体东向挤压而向东南运动的构造学推断。     

Subsidence et effondrements le long du littoral jordanien de la mer Morte : apports de la gravimétrie et de l'interférométrie radar différentielle

The Dead Sea shore is affected by major subsidence and sinkholes hazards due to the decrease of the sea level. The frequency of resulting accidents increased during the last four decades. Those phenomena could be at the origin of the catastrophic destruction of a major salt evaporation pond on 22 March 2000. In this paper, we show the main results of eight years of research in gravimetry and radar interferometry devoted to identify potentially hazardous areas, at different scales along the Jordanian Dead Sea coast, from the metric scale (gravimetric approach) to the kilometric one (interferometric approach). To cite this article: D. Closson et al., C. R. Geoscience 335 (2003).     

Identifying natural and anthropogenically-induced geohazards from satellite ground motion and geospatial data: Stoke-on-Trent,UK

Determining the location and nature of hazardous ground motion resulting from natural and anthropogenic processes such as landslides, tectonic movement and mining is essential for hazard mitigation and sustainable resource use. Ground motion estimates from satellite ERS-1/2 persistent scatterer interferometry (PSI) were combined with geospatial data to identify areas of observed geohazards in Stoke-on-Trent, UK. This investigation was performed within the framework of the EC FP7-SPACE PanGeo project which aimed to provide free and open access to geohazard information for 52 urban areas across Europe. Geohazards identified within the city of Stoke-on-Trent and neighbouring rural areas are presented here alongside an examination of the PanGeo methodology.A total of 14 areas experiencing ground instability caused by natural and anthropogenic processes have been defined, covering 122.35 km². These are attributed to a range of geohazards, including landslides, ground dissolution, made ground and mining activities. The dominant geohazard (by area) is ground movement caused by post-mining groundwater recharge and mining-related subsidence (93.19% of total geohazard area), followed by landsliding (5.81%). Observed ground motions along the satellite line-of-sight reach maxima of +35.23 mm/yr and −22.57 mm/yr. A combination of uplift, subsidence and downslope movement is displayed.‘Construction sites’ and ‘continuous urban fabric’ (European Urban Atlas land use types) form the land uses most affected (by area) by ground motion and ‘discontinuous very low density urban fabric’ the least. Areas of ‘continuous urban fabric’ also show the highest average velocity towards the satellite (5.08 mm/yr) and the highest PS densities (1262.92 points/km²) along with one of the lowest standard deviations. Rural land uses tend to result in lower PS densities and higher standard deviations, a consequence of fewer suitable reflectors in these regions. PSI is also limited in its ability to identify especially rapid ground motion. As a consequence the supporting geospatial data proved especially useful for the identification of landslides and some areas of ground dissolution. The mapped areas of instability are also compared with modelled potential geohazards (the BGS GeoSure dataset).     

Qualitative and quantitative assessment of TanDEM-X DEM over western Himalayan glaciated terrain

Glaciers have a high impact in the socio-economic sectors including water supply, energy production, flood and avalanches. A high precision digital elevation model (DEM) is required to monitor glaciers and to study various glacier processes. The present study deals with the qualitative and quantitative evaluation of the DEM generated from the bistatic TanDEM-X data by comparing it with GPS, Ice, Cloud, and land Elevation Satellite (ICESat) data and standard global DEMs such as Shuttle Radar Topography Mission (SRTM) and Advanced Space-borne Thermal Emission and Reflection Radiometer Global DEM (ASTER GDEM). The study area consists of highly undulating glaciated terrain in western Himalaya, India. The results reveal that TanDEM-X is slightly better than SRTM both qualitatively and quantitatively, whereas ASTER GDEM showing maximum discrepancy among the three DEMs. The Root Mean Square Error (RMSE) of the TanDEM-X DEM with respect to GPS is 3.5 m at lower relief and 11.9 m at glaciated terrain, against 6.7 and 12.5 m for SRTM and 9.3 and 19.8 m for ASTER GDEM, respectively, for the same sites. On an average, for the whole study area, the RMSE of TanDEM-X is 7.9 m, SRTM is 9.3 m and ASTER GDM is 14.2 m. The RMSE of TanDEM-X, SRTM and ASTER GDEM with respect to ICESat are 16.3, 19.9 and 101.1 m, respectively. It is evident from the analysis that though SRTM is closer to TanDEM-X in terms of accuracy in the mountainous terrain, however, TanDEM-X will be more useful for studying glacier dynamics and topography.     

桥梁振动监测雷达的设计与实现

针对传统桥梁振动检测方法过程复杂、成本高、精度低、效率低等问题,利用调频连续波技术和干涉测量技术,设计了一个操作方便、精度高、系统小、成本低的桥梁振动监测雷达。利用该雷达对北京地铁某一桥梁在过车时的振动状态进行了监测。试验结果表明该雷达能够准确测量桥梁的强迫振动和自振。所提出的由雷达回波相位反演桥梁形变信息的方法能够有效地测量桥梁振动状态,从而提高桥梁振动状态检测的分辨率及效率。该系统可以应用于桥梁的监测、预警和维护,具有广阔前景。