Wind-induced Response by Wavelet Transformed Gps Solutions

GPS solutions offer direct dynamic monitoring of long-span and tall civil structures. Timely and correct interpretation of the solutions is essential to improved monitoring and reduced number of false alarms. In this article, a new approach has been developed which employs the principal component analysis (PCA) of wavelet transformed GPS solutions to detect out-of-control signals. The methodology consists of pre-filtering the original GPS solutions via a FIR median hybrid (FMH) filter, and applying the PCA to the Haar wavelet transform (HWT) of the FMH-filtered results. It has been tested off-line using observation data from a monitoring experiment involving GPS and multi-sensors. Observation data were collected for about seven days in February 2000, including two strong wind periods. The PCA control chart of the wavelet transformed solutions was found to respond better to the wind periods compared to that of the "raw" solutions. The proposed method can be applied to monitor wind/earthquake or thermally-induced responses in the longterm deformation monitoring of large engineering structures by GPS. PhD Candidate, School of Surveying and Spatial Information Systems, University of NSW, Sydney NSW 2052, Australia. E-mail: [email protected] 2 Postdoc. Fellow, School of Surveying and Spatial Information Systems, University of NSW, Sydney NSW 2052, Australia. E-mail: [email protected] 3 Professor, School of Surveying and Spatial Information Systems, University of NSW, Sydney NSW 2052, Australia. E-mail: [email protected]