基于改进SBAS-InSAR技术的西南山区铁路沿线地表形变监测方法研究

Research on Surface Deformation Monitoring Method Along the Southwest Mountain Railway Based on Improved SBAS-InSAR Technology

合成孔径雷达干涉测量技术(Interferometric Synthetic Aperture Radar, InSAR)是一种新兴的对地观测手段,因其不受昼夜、云雨限制,被广泛应用于地表形变监测等领域。然而,受大气误差与失相干影响,InSAR技术仍然存在一些局限,尤其在植被茂密的西南山区,以SBAS-InSAR为代表的时间序列InSAR方法存在观测点不足的问题,难以开展山区变形监测。针对以上问题,考虑西南山区气候特征,设计改进的SBAS-InSAR时间序列处理方法,对干涉相位进行优化。丽香铁路是我国云南省境内一条连接丽江市与迪庆藏族自治州香格里拉的电气化铁路,是西部铁路网中滇藏铁路的重要组成部分。为保障丽香铁路安全稳定,同时验证上述方法的可用性,以丽香铁路段沿线的某段为研究区,利用星载SAR卫星存档影像数据对其周边地表开展历史形变探测,计算研究区近6.5年(2015年05月16日至2021年12月10日)的历史形变时间序列,并分析其影响范围、形变因素、变化规律等信息。最后将提出的改进后的SBAS-InSAR方法与常规InSAR方法比较,充分证明了所提出方法的优越性。

Interferometric Synthetic Aperture Radar(InSAR)is a novel method of ground observation,which is widely used in fields such as surface deformation monitoring due to the fact that it is unrestricted of day and night,as well as cloud and rain.However,due to measurement errors,InSAR technology still has some limitations,especially in the densely vegetated southwest mountainous areas.Time series InSAR,such as SBAS-InSAR receives insufficient observation points,making it difficult to carry out deformation monitoring in mountainous areas.In response to the above issues,this paper considers the atmospheric characteristics of the southwest mountainous areas and designs an improved SBAS-InSAR method to optimize the interferometric phase.The Lijiang-Shangrila Railway is an electrified railway connecting Lijiang City and Shangri-La in Diqing Tibetan Autonomous Prefecture in Yunnan Province.It is an important component of the Yunnan Tibet Railway in the Western Railway Network.In order to ensure the safety and stability of the Lijiang-Shangrila Railway and verify the availability of the above method,this paper takes a certain section along the Lijiang-Shangrila Railway as the experimental area,uses archived SAR data to estimate historical surface deformation,calculates the historical time series deformation of the target area for nearly six and a half years(May 16,2015 to December 10,2021),and analyzes their influence range,deformation factors,change patterns,and other information.Finally,the improved SBAS InSAR method proposed in this article is compared with conventional InSAR method,which fully demonstrates the superiority of the proposed method.