A new method for fast carrier phase ambiguity estimation

The Global Positioning System (GPS) double-difference carrier phase data are biased by an integer number of cycles. A new and successful method has been developed and demonstrated that enables very fast integer ambiguity estimation. The method makes use of an ambiguity reparametrization that allows one to reformulate the original ambiguity estimation problem into a new problem that becomes much easier to solve. The theoretical concepts of the method are presented, and some representative numerical results are given and discussed. In particular, it is demonstrated that a very significant reduction in both the correlation between the ambiguities and in the elongation of the corresponding confidence ellipsoid can be reached. Typically a reduction by a factor of between 10² and 10³ of the square-root of the condition number of the confidence ellipsoid can be obtained. Also the gain in time, which is needed to follow through the various computational steps, is demonstrated