Full-field 3D displacement measurement via microwave sensing

Full-field three-dimensional (3D) displacement measurement is highly sought after for the mechanical design, assessment, and health monitoring of large structures. The emerging microwave displacement measurement technique provides the potential for wide-ranging full-field measurement capabilities; however, it still faces challenges in achieving full-field 3D displacement measurement. In this article, we propose a novel approach for 3D displacement measurement across numerous measuring points within a full field of view, creating a unique microwave full-field 3D displacement measurement system that employs three microwave transceivers. Firstly, three non-collinear microwave transceivers and reference targets are employed to establish device coordinate system (DCS) and the structural coordinate system (SCS), respectively. Next, we outline the fundamental principle and the corresponding method for automatic matching of measuring points between different microwave transceivers, based on the transformation from SCS to microwave range-angle heatmaps. Furthermore, the 3D displacement reconstruction method in both DCS and SCS are rigorously detailed, followed by the implementation procedures for real-life measurements. Finally, simulation, experiment, and application validations demonstrate the performance of the proposed method, offering an appealing approach for microwave full-field 3D displacement measurement with high universality and accuracy.