Geodetic Monitoring of Tide Gauge Bench Marks with GPS

The aim of this paper is to determine the stability of tide gauge bench marks (including trigonometric stations) along the coast of Southern Australia. A series of bench marks were monitored using repeated Global Positioning System observations of South Australia. Their displacements were determined using three-dimensional network adjustment. Seventeen bench marks including twelve tide gauge sites were involved in the adjustment with two observation periods. The baseline lengths of the sites ranged from 178 km to 365 km. Individual day solutions were initially determined. These solutions were combined together and adjusted simultaneously imposing extended free net constraints on the parameters. The relative vertical heights of the bench marks are estimated, and the analysis indicated that the precision of the height differences were in the range of ±4.2 cm. © 1995, The Geodetic Society of Japan. All rights reserved.