Baseline Precision Results Using Triple Frequency Partial Ambiguity Sets

Adam Mowlam

Abstract:	The imminent arrival of a European satellite constellation called Galileo and the modernisation of the Global Positioning System (GPS) provide an opportunity for satellite-based positioning employing an integrated (GPS+Galileo) and/or triple frequency positioning solution. Taken together they are anticipated to have a positive impact on fast ambiguity resolution, hopefully over longer distances than are currently achievable with GPS alone. Additionally, Australia has the unique opportunity to receive broadcast signals from the Japanese Quasi-Zenith Satellite System (QZSS). Simulated QZSS observations will be included in the various tests designed to explore the impact on baseline precision results. The aim of this paper is to briefly quantify the ambiguity estimation performance when using triple frequency observations from GPS, Galileo and QZSS in both single and combined system modes. The paper will show that it is often difficult to correctly resolve a large set of ambiguities (near) instantaneously, particularly when the baseline length exceeds 40km. It will then be demonstrated that resolving only part of the ambiguity set (partial ambiguity resolution) could lead to improvements in baseline precision. Two approaches to defining the partial ambiguity subset are explored: classical partial ambiguity resolution based on ordered ambiguity variances and a per-satellite approach using elevation-ordering. Finally, the paper concludes by quantifying the impact that the fail rate has in determining the size of the partial ambiguity set.
Published in:	Proceedings of the 17th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2004) September 21 - 24, 2004 Long Beach Convention Center Long Beach, CA
Pages:	2509 - 2518
Cite this article:	Mowlam, Adam, "Baseline Precision Results Using Triple Frequency Partial Ambiguity Sets," Proceedings of the 17th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2004), Long Beach, CA, September 2004, pp. 2509-2518.
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