Data Processing and Multipath Mitigation for GPS/Accelerometer Based Hybrid Structural Deflection Monitoring System

G. W. Roberts, X. Meng and A. H. Dodson

Abstract:	Research using kinematic GPS and triaxial accelerometers for monitoring structural deflection is conducted at the IESSG, the University of Nottingham. In this paper, a GPS/accelerometer instrument layout for monitoring a suspension footbridge with known loading is introduced. It comprises of three Leica SR530 GPS receiver bridge observation sites with one Kistler triaxial accelerometer installed on one of the middle span sites, two riverside GPS reference stations of the same type of receiver and another two reference stations located 3.6km away. With such a receiver configuration, some main factors affecting the GPS/accelerometer data quality, especially in the context of bridge monitoring, are analysed. Through a numerical example of the relative tropospheric delay, the local microclimate effects on the positioning precision are investigated. The relative tropospheric delay estimates from different models are further compared, including the results from the Adaptive Filtering (AF) approach. A concept of relative tropospheric delay double differencing is presented based on a designated reference station group with the attempt to effectively reduce relative tropospheric delay to a minimum level. In this paper, the authors also present an AF-based hierarchical algorithm used to separate real bridge movements from relative tropospheric delay, multipath and the receiver random noise both on the reference stations and observation stations. The data sets collected from the bridge trails are used to demonstrate the feasibility of the proposed approach. Spectral analysis is employed to validate the AF results through the natural frequency comparison with the accelerometer data.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	473 - 508
Cite this article:	Roberts, G. W., Meng, X., Dodson, A. H., "Data Processing and Multipath Mitigation for GPS/Accelerometer Based Hybrid Structural Deflection Monitoring System," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 473-508.
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