Modal Parameters Identification of Bridge Structures from GNSS Data Using the Improved Empirical Wavelet Transform

It is difficult to accurately identify the dynamic deformation of bridges from Global Navigation Satellite System (GNSS) due influence multipath effect and random errors, etc. To solve this problem, an improved empirical wavelet transform (EWT)-based procedure was proposed denoise GNSS data modal parameters bridge structures. Firstly, Yule–Walker algorithm-based auto-power spectrum Fourier were jointly adopted segment frequency bands structural response data. Secondly, EWT algorithm used decompose reconstruct according a correlation coefficient-based criterion. Finally, Natural Excitation Technique (NExT) Hilbert Transform (HT) applied structures decomposed efficient components. Two groups simulation validate feasibility reliability method, which consisted vibration responses four-storey steel frame model, acceleration suspension bridge. Moreover, field experiments carried out on Wilford in Nottingham, UK, with accelerometer. The fundamental (1.6707 Hz), damping ratio (0.82%), as well maximum displacements (10.10 mm) detected by using method measurements, consistent accelerometer results. In conclusion, analysis revealed that EWT-based capable identifying low-order, closely spaced under operational conditions.