Advances in Ambiguity Resolution for RTK Applications Using the New RTCM V3.0 Master-Auxiliary Messages

N. Brown, R. Keenan, B. Richter and L. Troyer

Abstract:	With the release of RTCM 3.0 there is, for the first time, a standardized way of transmitting GPS corrections from a network of reference stations. The network messages used in RTCM 3.0 are based on the Master-Auxiliary Concept jointly proposed by Leica Geosystems and Geo++. The idea behind the Master-Auxiliary concept is to provide the raw observation data of the network, free of any proprietary modelling, to the rover in a highly compact way so that the rover has full knowledge and control over how the network corrections are applied for its position solution. The distinct advantages of RTCM 3.0 Master- Auxiliary corrections over earlier approaches are the standardized, open and compact nature of the format, the suitability of the format for broadcast communications and the flexibility given to the rover in deciding how best to apply the network corrections. The aim of this paper is to assess how the advantages of the Master-Auxiliary concept translate into benefits for the user. The advances in ambiguity resolution are achieved by combining standard techniques such as stochastic modelling of the ionosphere and repeated validation of independent ambiguity sets with an innovative interpolation of the network corrections. For the analysis, empirical data are used from a real reference network possessing a number of challenging characteristics, such as large separations between stations in terms of both distance and height. Continuous testing was run over an extended period providing the basis for the first true long-term statistical analysis of rover performance when using Master-Auxiliary corrections. Direct comparisons are made against VRS and FKP and it is clearly shown that Master-Auxiliary concept offers superior performance in terms of time to fix, reliability of ambiguity resolution and accuracy.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	73 - 80
Cite this article:	Brown, N., Keenan, R., Richter, B., Troyer, L., "Advances in Ambiguity Resolution for RTK Applications Using the New RTCM V3.0 Master-Auxiliary Messages," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 73-80.
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