Measuring geocentric radial coordinates with a non-fiducial GPS network

Abstract

In this paper we address the problem of estimating the short term precision of the geocentric radial coordinate of a GPS receiver placed on the Earth crust using a non-fiducial approach. The network used in our analysis contains 35 receivers distributed globally. We have analyzed the data with two different strategies: global and regional. In the global strategy the results obtained, which are compatible with those of Heflin et al. (1992) and Blewitt et al. (1992), provide a weighted root mean square of the residuals (wrms) one order of magnitude larger than the formal errors of the individual estimates. Our regional strategy is based on the assumption that errors in the orbit determination induce errors in the receiver positions, correlated up to large scales. This approach allows us to obtain a significant agreement between the wrms and the formal errors.