Abstract
In recent years, the enormous losses caused by urban surface deformation have received more and more attention. Traditional geodetic techniques are point-based measurements, which have limitations in using traditional geodetic techniques to detect and monitor in areas where geological disasters occur. Therefore, we chose Interferometric Synthetic Aperture Radar (InSAR) technology to study the surface deformation in urban areas. In this research, we discovered the land subsidence phenomenon using InSAR and Global Navigation Satellite System (GNSS) technology. Two different kinds of time-series InSAR (TS-InSAR) methods: Small BAseline Subset (SBAS) and the Permanent Scatterer InSAR (PSI) process were executed on a dataset with 31 Sentinel-1A Synthetic Aperture Radar (SAR) images. We generated the surface deformation field of Shenzhen, China and Hong Kong Special Administrative Region (HKSAR). The time series of the 3d variation of the reference station network located in the HKSAR was generated at the same time. We compare the characteristics and advantages of PSI, SBAS, and GNSS in the study area. We mainly focus on the variety along the coastline area. From the results generated by SBAS and PSI techniques, we discovered the occurrence of significant subsidence phenomenon in the land reclamation area, especially in the metro construction area and the buildings with a shallow foundation located in the land reclamation area.
Highlights
Traditional geodetic methods represented by levelling or total station geometry are point-based measurements
From the results generated by Small BAseline Subset (SBAS) and Permanent Scatterer InSAR (PSI) techniques, we discovered the occurrence of significant subsidence phenomenon in the land reclamation area, especially in the metro construction area and the buildings with a shallow foundation located in the land reclamation area
From the original geodetic workflow, we can find that the traditional geodetic survey method has two significant characteristics: The first is the necessity of setting up the observation stations and observation markers
Summary
Traditional geodetic methods represented by levelling or total station geometry are point-based measurements. The other one is the long working time-consuming of each period of observations The former characteristic leads to an insufficient spatial sampling rate of monitoring results which is unable to discover new deformation areas from the monitoring results effectively, especially when the monitoring scope is relatively extensive, and the latter one limits the temporal sampling rate of monitoring results of the station or the observation marker. Bing Xu et al studied the land reclamation area with ENVISAT data [19] In these examples, InSAR technology provides researchers with a reliable way of generating land deformation velocity fields. One applies the small baseline differential interferogram to the surface deformation inversion model, which can obtain the deformation time series of the coherent target, while ensuring that the factors affecting the interferometric quality of the interferogram are estimated and removed. To provide satellite coordinate information to maximize the accuracy of the baseline solution
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