Deformation Monitoring Scheme using Static

Michael A. Duffy, Cecilia Whitaker

Abstract:	The Metropolitan Water District (MWD) of Southern California currently has 31 facilities with structures (in-cluding concrete dams, earthen dams, lined reservoirs, power plants and water filtration basins) that require structural deformation monitoring of some kind. For more than 20 of these facilities, three dimensional data (X,Y and Z) is collected on a twice yearly schedule. An eco-nomical method was developed to utilize the fast growing network of Continuous Operating Reference Stations (CORS) that are being installed over Southern California for crustal motion studies. Using two CORS stations as fixed base stations (or one CORS and one on-site receiver as a base), two vectors are measured to each deformation monument. These two vectors are processed with the pre-cise ephemeris and analyzed with a least squares solution to determine the relative position of the monument. This relative position is remeasured every six months and com-pared to the previously established positions to study trends in the structural deformation. Utilizing two vectors from two fixed CORS stations, instead of creating a typi-cal survey network, prevents contamination of data from possible errors at neighboring monuments. Also, these surveys incorporated the use of fixed height tripods to prevent height errors and choke ring antennas to reduce multipath. This method has resulted in excellent repeat-ability of the horizontal position for deformation trend analysis. The vertical position is still being obtained with electronic leveling methods at this time.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	63 - 70
Cite this article:	Duffy, Michael A., Whitaker, Cecilia, "Deformation Monitoring Scheme using Static," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 63-70.
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