Toward Fine Surveillance: A review of multitemporal interferometric synthetic aperture radar for infrastructure health monitoring

With improvements in synthetic aperture radar (SAR) image resolutions and multitemporal SAR interferometry (MTInSAR) algorithms, it becomes feasible to generate 3D point clouds with millimeter deformation accuracy to monitor urban infrastructure health in detail. This article reviews the progress and challenges of MT interferometric SAR (InSAR) techniques for infrastructure deformation monitoring, with an emphasis on refinement performance. After a brief overview of literature statistics, we examine characteristics of the main MTInSAR algorithms. We demonstrate performance refinement in terms of point density, height accuracy, and deformation accuracy, using a comparative study of the reclaimed Hong Kong International Airport (HKIA). A series of typical infrastructure dynamic behaviors in urban areas revealed by MTInSAR is then illustrated. This article also describes key issues that remain to be addressed to facilitate operational fine surveillance. Finally, we go beyond MTInSAR to illustrate intelligent infrastructure diagnosis systems applicable to city-scale and even infrastructural component-scale analysis. It is our expectation that this review will provide a reference and guidance for future research and applications of MTInSAR in urban infrastructure monitoring.