Development of a 6-DOF dynamic responses measurement system fusing RTK-GPS sensor and accelerometer for structural health monitoring

Abstract

This thesis proposes a 6-DOF dynamic response measurement system incorporating a low-cost RTK-GPS sensor and a force feedback accelerometer for structural health monitoring. The proposed system consists of (1) a sensor module integrating a RTK-GPS sensor and a force feedback accelerometer into a single unit, (2) GPS base module for transmitting observation messages to sensor modules, and (3) computational module for estimating 6 DOF structural responses in real-time. The sensor module measures acceleration, velocity and displacement of target structure with sampling rates of 100 Hz, 10Hz, and 10Hz, respectively, and transmits the measurements to the computational module. While sensor module measures, GPS base module transmits observation messages to sensor module for guaranteeing RTK technique application at sensor module. Computation module processes the measurement data from sensor module to estimate the precise and accurate 6-DOF dynamic responses using a combination of data process techniques such as a reliability assessment filter, IIR filter, inclination function, and a two-stage Kalman estimator. For verifying measurement performance, a 1Hz sinusoidal vibration test, DC to 10Hz random vibration test, and a rotation test were implemented. Additionally, for verifying field applicability, a field test at Penang Second Bridge, Malaysia was implemented by comparing the proposed system with a commercial RTK-GNSS sensor.