MIMO-SAR for Structural Health Monitoring
The increasing necessity of structural health monitoring (SHM) is pushing the development of new methods and technologies. Multiple input multiple output synthetic aperture radar (MIMO-SAR) systems can be of relevance in this field as they are economically (low-cost equipment, low-maintenance cost, low-power consumption, etc.) and scientifically (high acquisition rate, high spatial resolution, potential for 3D radar imaging, information content of data, etc.) interesting for the assessment of deformations. However, MIMO-SAR systems are not yet understood well enough for practical application in SHM. In this project, we investigate the applicability of a specific low-cost, automotive-grade, electronically configurable MIMO-SAR system (TIDEP-01012) for SHM. We focus on key characteristics for the intended applications like data quality of the phase observations, sensitivity to detect vibrations and measurement of displacement vectors, develop suitable test procedures for this investigation, design and build required auxiliary equipment.
First experiments have just been completed both indoors and outdoors (see Figure 2). Using a corner reflector mounted on a precision translation stage and moved electronically in steps of only 25μm we found very encouraging first results indicating that the phase quality of the sensor is sufficient to detect these small steps, and the maximum deviations between accumulated displacements obtained during repetitions of the experiment under various weather conditions (i.e. fog, sunshine, and cloud cover) were below 0.2 mm.
Application to a road bridge with known deformations of 1-2mm under heavy traffic load as well as measurements on other artificial structures and utilising two or more sensors at the same time are envisaged for the near future.
Contact
Geosensorik und Ingenieurgeodäsie
Stefano-Franscini-Platz 5
8093
Zürich
Switzerland