Configuration and Performance Test of GNSS-IMU Sensor Fusion Module for Structural Displacement Measurement

Detecting the displacement of a structure by external forces in advance is very important in monitoring the health of the structure. In this study, a kind of sensor fusion technique that combines low-cost GNSS and IMU for structural displacement measurement was established. In addition, a data acquisition program that can secure the synchronous measurement between sensors was created. In order to evaluate the performance of this measurement module, a model experiment gauging the true value by the laser displacement meter was performed, and the results of GNSS single positioning, VRS positioning, precision single positioning (PPP), and sensor merging positioning were compared and analyzed. As a result, it was found that the PPP positioning did not capture the vibration of the structure at all regardless of the waiting time within the excitation condition of the model structure. On the other hand, GNSS single positioning was able to obtain similar results to true values and VRS positioning by pre-processing with an appropriate high-pass filter and the sensor fusion technique.