Linking Persistent Scatterers to the Built Environment Using Ray Tracing on Urban Models

Abstract

Persistent scatterers (PSs) are coherent measure-1 ment points obtained from time series of satellite radar images, 2 which are used to detect and estimate millimeter-scale displace-3 ments of the terrain or man-made structures. However, asso-4 ciating these measurement points with specific physical objects 5 is not straightforward, which hampers the exploitation of the 6 full potential of the data. We have investigated the potential 7 for predicting the occurrence and location of PSs using generic 8 3-D city models and ray-tracing methods, and proposed a 9 methodology to match PSs to the pointlike scatterers predicted 10 using RaySAR, a ray-tracing synthetic aperture radar simulator. 11 We also investigate the impact of the level of detail (LOD) of the 12 city models. For our test area in Rotterdam, we find that 10% 13 and 37% of the PSs detected in a stack of TerraSAR-X data 14 can be matched with point scatterers identified by ray tracing 15 using LOD1 and LOD2 models, respectively. In the LOD1 case, 16 most matched scatterers are at street level while LOD2 allows 17 the identification of many scatterers on the buildings. Over 18 half of the identified scatterers easily correspond to identify 19 double or triple-bounce scatterers. However, a significant fraction 20 corresponds to higher bounce levels, with approximately 25% 21 being fivefold-bounce scatterers. 22 Index Terms-Level of detail (LOD), persistent scatterers 23 (PSs), ray tracing, simulation, synthetic aperture radar (SAR). 24 I. INTRODUCTION 25 P ERSISTENT scatterer (PS) interferometry (PSI) [1] is 26 a geodetic technique to measure surface displacements 27 using multiepoch synthetic aperture radar (SAR) images.

A treatise on InSAR geometry and 3D displacement estimation

“…While condition 1 is trivial, the second condition is related to the spatial part of the STCI LoS observations and is essential since scatters close to each other are not per definition stemming from the same object, e.g., consider a scatterer on the roof of a founded house and a scatterer nearby on the street, which both represent different deformation phenomena. Added to this, different objects (or parts of objects) can show different deformation phenomena [15], [16].…”

Insar Maps of Land Subsidence and Sea Level Scenarios to Quantify the Flood Inundation Risk in Coastal Cities: The Case of Singapore

“…Such PS' may reflect two problems: incorrect geolocation and overestimated surface deformation. Recently, an approach based on the use of generic urban models has been proposed [38]. However, the applicability of this approach is quite limited and expensive when based on a laser scanning Digital Surface Model (DSM) of the city.…”

On the value of corner reflectors and surface models in InSAR precise point positioning

“…To fix the ∆a, ∆r, and c 0 of PSs, these PSs need to be matched with corresponding points in the LiDAR point cloud. We use the Iterative Closest Point method (ICP) with the PS positioning ellipsoids (Hanssen et al, 2018;Yang et al, 2019), which minimizes the differences between two clouds of points in an iterative way and generates transformation parameters.…”