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

摘要

With the release of RTCM 3.0 there is, for the first time, arnstandardized way of transmitting GPS corrections from arnnetwork of reference stations. The network messages usedrnin RTCM 3.0 are based on the Master-Auxiliary Conceptrnjointly proposed by Leica Geosystems and Geo++. Thernidea behind the Master-Auxiliary concept is to provide thernraw observation data of the network, free of anyrnproprietary modelling, to the rover in a highly compactrnway so that the rover has full knowledge and control overrnhow the network corrections are applied for its positionrnsolution. The distinct advantages of RTCM 3.0 Master-rnAuxiliary corrections over earlier approaches are thernstandardized, open and compact nature of the format, thernsuitability of the format for broadcast communicationsrnand the flexibility given to the rover in deciding how bestrnto apply the network corrections. The aim of this paper isrnto assess how the advantages of the Master-Auxiliaryrnconcept translate into benefits for the user. The advancesrnin ambiguity resolution are achieved by combiningrnstandard techniques such as stochastic modelling of thernionosphere and repeated validation of independentrnambiguity sets with an innovative interpolation of thernnetwork corrections.rnFor the analysis, empirical data are used from a realrnreference network possessing a number of challengingrncharacteristics, such as large separations between stationsrnin terms of both distance and height. Continuous testingrnwas run over an extended period providing the basis forrnthe first true long-term statistical analysis of roverrnperformance when using Master-Auxiliary corrections.rnDirect comparisons are made against VRS and FKP and itrnis clearly shown that Master-Auxiliary concept offersrnsuperior performance in terms of time to fix, reliability ofrnambiguity resolution and accuracy.