Structural Health Monitoring of a Traffic Signal Support Structure Based on 5.8-GHz Doppler Radar with Median Filter and Revised Circle Fitting

This paper introduces a new technique to obtain accurate measurements of a traffic signal’s mast arm using Doppler radar. A common challenge in extracting oscillatory displacement from the Doppler phase history is examined, and its major cause is also revealed. Consequences of both numerical simulation and experimental validation show that sudden jumps in Doppler radar measurements can be removed through a technique based on median filtering and a revised circle fitting algorithm. The proposed technique can have broad applications in radar-based structural vibration monitoring.