An improved GNSS dynamic monitoring performance evaluation method

The dynamic monitoring of buildings based on global navigation satellite system (GNSS) is beneficial in assessing health status and verifying design parameters. Current GNSS dynamic monitoring and evaluation methods still have problems during signal decomposition, such as strong noise interference, mode aliasing and error components generated by over-decomposition or under-decomposition. This paper comprehensively determines the key parameter of variational mode decomposition (VMD) (i.e. decomposition mode number) based on the decomposition components and residuals of VMD and proposes an improved VMD-Hilbert transform (IVMD-HT) GNSS dynamic monitoring performance evaluation method to conduct performance evaluation and feature extraction of GNSS dynamic monitoring. This work demonstrates the feasibility and applicability of the method through simulation and field experiments. The results reveal that the method proposed in this article can achieve the decomposition and noise reduction of GNSS monitoring data effectively. Moreover, the monitoring accuracy of low-cost GNSS receivers combined with this method can be improved by 10 %. Compared with commercial-grade GNSS receivers of different brands, the monitoring accuracy can be improved by 5 %–15 %, which can meet the needs of dynamic monitoring and reach commercial level applications. Furthermore, under the influence of wind-induced environment, the vibration frequency of GNSS dynamic monitoring is mainly between 0 and 0.01 Hz, and the overall impact on buildings is small. The IVMD-HT GNSS dynamic monitoring performance evaluation method can effectively and comprehensively determine the optimal mode number of VMD, achieve signal extraction and noise removal, perform modal analysis and feature extraction, and provide a new processing method for structural performance evaluation and damage detection.