Smart Radar Sensor Network for Bridge Displacement Monitoring

Measuring static or dynamic displacement is often an integral component of evaluating bridge conditions. This article introduces a wireless, low-cost, and high-accuracy smart radar sensor network to measure bridge displacement. This sensor technology consists of two major systems, a continuous-wave radar sensor and a wireless smart sensor network platform. The continuous-wave radar sensor, paired with an active transponder, has demonstrated submillimeter accuracy for structural displacement measurements. The hardware and software designs of the sensor network are presented in this article. The WiSeMote wireless sensor platform is adopted to establish a sensor network synchronized to the microsecond level. Critical performance metrics of the sensor network are quantified, including power consumption and wireless transmission range. The sensor network's static and dynamic measurement accuracy have also been verified in a series of pedestrian bridge experiments. In addition, the ability of the sensor network to detect the vehicle speed is validated.