Small Reflectors for Ground Motion Monitoring With InSAR

Abstract

In recent years, synthetic aperture radar interferometry has become a recognized geodetic tool for observing ground motion. For monitoring areas with low density of coherent targets, artificial corner reflectors (CRs) are usually introduced. The required size of a reflector depends on radar wavelength and resolution and on the required deformation accuracy. CRs have been traditionally used to provide a high signal-to-clutter ratio (SCR). However, large dimensions can make the reflector bulky, difficult to install and maintain. Furthermore, if a large number of reflectors are needed for long infrastructure, such as vegetation-covered dikes, the total price of the reflectors can become unaffordable. On the other hand, small reflectors have the advantage of easy installation and low cost. In this paper, we design and study the use of small reflectors with low SCR for ground motion monitoring. In addition, we propose a new closedform expression to estimate the interferometric phase precision of resolution cells containing a (strong or weak) point target and a clutter. Through experiments, we demonstrate that the small reflectors can also deliver displacement estimates with an accuracy of a few millimeters. To achieve this, we apply a filtering method for reducing clutter noise.

Applicability of satellite radar imaging to monitor the conditions of levees

“…Positioning of the PS points is less precise than their deformation estimates. The positioning precision is 1-2 m for C-band data and less than 1 m for X-band data (Dheenathayalan, Cuenca, Hoogeboom, & Hanssen, 2017). Using the exact PS locations, reflections from the ground can be separated from those originating from higher level objects, which may show a different deformation behaviour (Dheenathayalan, Small, Schubert, & Hanssen, 2016).…”

3-D Positioning and Target Association for Medium-Resolution SAR Sensors

“…2) Impact of the SCR of Scatterers: Given the SCR of a target (P), the impact of interferometic phase variance σ φ P on the precision of cross-range σ c P,SCR can be approximated (for SCR > 1 dB) by [25, pp. 34-50] [26]…”

Monitoring Deformation along Railway Systems Combining Multi-Temporal InSAR and LiDAR Data

“…The individual CS positioning precision is dependent on the sub-pixel positionand the relative height of the scatterers [6,23]. The precision with which these parameters can be estimated depends on the SAR mission characteristics, e.g., spatial resolution and the orbital tube dimensions.…”

“…The precision with which these parameters can be estimated depends on the SAR mission characteristics, e.g., spatial resolution and the orbital tube dimensions. For each CS, the uncertainty in the position is described by a 3D positioning error ellipsoid [23]. Van Natijne A and Hanssen [21] introduced an approach to use the position error ellipsoids to snap the CS point cloud to a LiDAR point cloud.…”