Title
MIMO-SAR Interferometric Measurements for Structural Monitoring: Accuracy and Limitations
Abstract
Terrestrial Radar Interferometry (TRI) is a measurement technique capable of measuring displacements with high temporal resolution at high accuracy. Current implementations of TRI use large and/or movable antennas for generating two-dimensional displacement maps. Multiple Input Multiple Output Synthetic Aperture Radar (MIMO-SAR) systems are an emerging alternative. As they have no moving parts, they are more easily deployable and cost-effective. These features suggest the potential usage of MIMO-SAR interferometry for structural health monitoring (SHM) supplementing classical geodetic and mechanical measurement systems. The effects impacting the performance of MIMO-SAR systems are, however, not yet sufficiently well understood for practical applications. In this paper, we present an experimental investigation of a MIMO-SAR system originally devised for automotive sensing, and assess its capabilities for deformation monitoring. The acquisitions generated for these investigations feature a 180 degrees Field-of-View (FOV), distances of up to 60 m and a temporal sampling rate of up to 400 Hz. Experiments include static and dynamic setups carried out in a lab-environment and under more challenging meteorological conditions featuring sunshine, fog, and cloud-cover. The experiments highlight the capabilities and limitations of the radar, while allowing quantification of the measurement uncertainties, whose sources and impacts we discuss. We demonstrate that, under sufficiently stable meteorological conditions with humidity variations smaller than 1%, displacements as low as 25 mu m can be detected reliably. Detecting displacements occurring over longer time frames is limited by the uncertainty induced by changes in the refractive index.
Year
DOI
Venue
2021
10.3390/rs13214290
REMOTE SENSING
Keywords
DocType
Volume
MIMO-SAR, interferometery, FMCW radar, displacement measurement, multiple targets, W-band, structural health monitoring
Journal
13
Issue
Citations 
PageRank 
21
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Andreas Baumann-Ouyang100.34
Jemil Avers Butt200.34
David Salido Monzú310.70
Andreas Wieser4387.88