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Abstract:
Monitoring of dynamic motion is crucial to analyse response of civil engineering structures and ground motion. Several methodologies have been developed the last decades, where various sensors can be combined with GNSS receivers to monitor the dynamic motion (displacement, acceleration, tilt, etc.). GNSS technology is one of the methods which are applied with the main advantage the direct measurement of the displacement in an independent global coordinate system. However, the high cost of the GNSS stations, consisted of dual frequency receiver and geodetic GNSS antenna, is the main reason of the limited application of GNSS for deformation monitoring. In the current study, we assess the accuracy of low-cost multi-GNSS receivers in monitoring dynamic motion. The accuracy of low-cost GNSS receivers were assessed against high-performance dual frequency GNSS receivers, by executing controlled circular motion of predefined radius, ranging between 5 to 50cm, and frequency up to 0.5 Hz. From the analysis of the GNSS measurements it was assessed the contribution of multi-GNSS constellation and the deployment of two closely-spaced low-cost GNSS receivers to model their common errors. Both approaches proved to be beneficial by enhancing the performance of low-cost GNSS receivers in terms of accuracy and availability. Then, the same approach of combining two low-cost GNSS receivers to monitor Wilford pedestrian bridge was applied. The analysis of the two low-cost GNSS receivers led to enhance their accuracy and reach accuracy of the dual frequency GNSS receiver. Furthermore, the modal frequency of the bridge was accurately detected by the low-cost GNSS receivers.
