Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-19T03:39:20.362Z Has data issue: false hasContentIssue false

An Efficient Worst User Location Algorithm for the Generation of the Galileo Integrity Flag

Published online by Cambridge University Press:  23 August 2006

Shaojun Feng
Affiliation:
Imperial CollegeLondon Email: [email protected]
Washington Y. Ochieng
Affiliation:
Imperial CollegeLondon Email: [email protected]

Abstract

This paper proposes a computation method for the determination of the worst user location (WUL) instead of the current grid search-based methods. The WUL is a key parameter in the estimation of the Galileo integrity data. Since a satellite clock error is the same for all users whereas the orbital error is different depending on the location of users, the WUL depends on the satellite orbit errors which can be estimated using the measurements from the Galileo sensor stations. The proposed algorithm uses the resolved orbital errors to calculate an approximate WUL on a spherical model of the Earth. The next step is to determine the WUL on a specified ellipsoid model using an iterative transformation process. Results show that the proposed method is more accurate and computationally efficient than the current search-based methods. The computation time required is minimal making it valuable in meeting the real time requirements for the generation of the Galileo integrity flag.

Type
Research Article
Copyright
Copyright © The Royal Institute of Navigation 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES AND BIBLIOGRAPHY

Blomenhofer, H., Ehret, W., Leonard, A., and Blomenhofer, E. (2004). GNSS/Galileo Global and Regional Integrity Performance Analysis, Proceedings of ION GNSS 2004, 21–24 September 2004, Long Beach, CA, USA. 21582168Google Scholar
Dellago, R., Pieplu, J., and Stalford, R. (2003). The Galileo system architecture at the end of the design phase. Proceedings of ION GPS/GNSS 2003, 9–12 September 2003, Portland, Oregon, USA. 978990Google Scholar
Medel, C. H., Virgilli, L. P., Garcia, A. M., Piedelobo, J. R. M., and Merion, M. M. R. (2002). SISA computation algorithm and their applicability for Galileo integrity. Proceedings of ION GPS 2002, 24–27 September 2002, Portland, Oregon, USA. 21732184Google Scholar
Werner, W., Zink, T., Lohnert, E., and Pielmeier, J. (2001) Galileo integrity performance assessment (GIPA). Proceedings of ION GPS 2001, 11–14 September 2001, Salt Lake, Utah, USA. 18381849Google Scholar