测绘地理信息

陆地探测一号01组A/B卫星(LT-1A/1B)先后于2022年1月26日、2月27日在酒泉卫星发射中心成功发射，是我国首颗L波段的合成孔径雷达(synthetic aperture radar,SAR)卫星。为研究LT-SAR卫星在城市高植被区的相干性及融合升降轨地表形变监测效果，本文以杭州市余杭区为研究区域。研究采用D-InSAR(Differential Interferometric Synthetic Aperture Radar)技术，分别对LT-SAR影像和RADARSAT-2影像进行处理，并对监测结果相关性和影像相干性进行量化分析。结果表明，两颗SAR卫星的形变监测结果具有较高的一致性。通过干涉对相干性量化分析发现，LT-SAR影像在植被穿透能力上表现突出，尤其在城市植被密集区域能够获取高相干性的监测点；而C波段的RADARSAT-2影像由于波长较短，在植被覆盖区域的相干性有所降低。此外，融合升降轨道SAR影像可有效提升地质灾害探测能力，此次监测发现余杭区部分道路存在异常形变，其中仓前街道形变较为严重。结合光学影像对比分析，沉降主要受周边工地施工影响。研究表明，L波段和C波段SAR影像的结合能有效提升城市植被覆盖区域地表形变监测的精确度和可靠性，未来随着LT-SAR数据的积累可以结合时序InSAR技术，实现长时域高精度的监测。

The LT-1A/1B satellite of the Land Exploration No.1 01 group were successfully launched from the Jiuquan Satellite Launch Center on January 26 and February 27, 2022.They are China's first L-band synthetic aperture radar(SAR) satellite.In order to study the coherence of LT-SAR satellites in urban high vegetation areas and the monitoring effect of ground deformation by integrating ascending and descending orbits, this study takes Yuhang District, Hangzhou City as the research area.In this research,the Differential interferometric synthetic aperture radar(D-InSAR) technology is adopted to process LT-SAR images and RADARSAT-2 images respectively.Quantitative analyses are then conducted on the correlation of monitoring results and the coherence of the images.The results show that the deformation monitoring results of the two SAR satellites have high consistency.The quantitative analysis of interferometric pair coherence reveals ithat LT-SAR images exhibit outstanding vegetation penetration capability, and could obtain monitoring points with high coherence especially in urban areas with dense vegetation.In contrast, due to its shorter wavelength, the C-band RADARSAT-2 images show reduced coherence in vegetation-covered areas.In addition, fusing SAR images from ascending and descending orbits could effectively improve the detection capability of geological hazards.In this monitoring, abnormal deformation is detected in some roads in Yuhang District, among which the deformation in Cangqian Sub-district is relatively serious.Comparative analysis with optical images indicated that the subsidence is mainly affected by the construction activities of surrounding construction sites.The study demonstrates that the combination of L-band and C-band SAR images can effectively improve the accuracy and reliability of surface deformation monitoring in urban vegetation-covered areas.In the future, with the accumulation of LT-SAR data, it will be possible to combine multi-temporal InSAR technology to achieve long-term and high-precision monitoring.