The Accuracy of GPS Water Vapour Estimation

A. H. Dodson and H. C. Baker

Abstract:	Ground-based GPS has shown itself to be an excellent sensor of atmospheric water vapour, providing estimates of Integrated Precipitable Water Vapour at around lmm resolution. Comparisons of GPS water vapour estimates with radiosondes and radiometer observations has been made by several groups. There has often been evidence of systematic biases between the systems which cannot always be easily explained. It is essential to determine the source of any bias in the GPS estimates, and hence to better assess the absolute accuracy of GPS water vapour estimation, particularly if the system is to be used for long term studies of global water vapour for climate purposes. A comparison has therefore been made of GPS water vapour estimates resulting from three different software processing packages, namely, BERNESE, GAS and GIPSY, and the results of the comparison, including a further comparison with radiometer data are presented in this paper. In addition, comparisons of various post-data and predicted orbits have been carried out to evaluate the likely effect of orbit error on real-time GPS water vapour estimation for forecast purposes. Thus, the paper presents results of likely accuracies for both long-term and real-time applications of GPS water vapour measurement. This work has been carried out as part of the collaborative EC funded WAVEPRONT project.
Published in:	Proceedings of the 1998 National Technical Meeting of The Institute of Navigation January 21 - 23, 1998 Westin Long Beach Hotel Long Beach, CA
Pages:	649 - 657
Cite this article:	Dodson, A. H., Baker, H. C., "The Accuracy of GPS Water Vapour Estimation," Proceedings of the 1998 National Technical Meeting of The Institute of Navigation, Long Beach, CA, January 1998, pp. 649-657.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In