A Modified Lambda Method for Ambiguity Resolution in the Presence of Position Domain Constraints

Ralf Monikes, Jan Wendel, Gert F. Trommer

Abstract:	The least-square ambiguity decorrelation adjustment method (LAMBDA) is one of the most appropriate techniques for GNSS carrier phase ambiguity resolution. The LAMBDA method is an algorithm for searching the most likely integer ambiguity combination. Based on a floating least-squares estimation of integer ambiguities, it minimizes the quadratic norm of the residuals. As the search is situated in the ambiguity space, known constraints in the position domain (e.g. known base line length) can not directly be applied to the search algorithm. In this paper a new algorithm is proposed, which is based on the LAMBDA search algorithm. It transforms the constraints from the position domain into the ambiguity space and embeds the constraints into the conditional calculation of the search bounds of the first three ambiguities. Thus a new algorithm is derived which resolves ambiguities in a shorter time with higher reliability in comparison to the original LAMBDA search without constraints.
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:	81 - 87
Cite this article:	Monikes, Ralf, Wendel, Jan, Trommer, Gert F., "A Modified Lambda Method for Ambiguity Resolution in the Presence of Position Domain Constraints," 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. 81-87.
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