Summary of Network RTK Reference Station Ambiguity Determination

Three different methods of network RTK reference station ambiguity determination are introduced, summarized and evaluated in this paper: The three-step method to determine double-differenced ambiguities resolution of reference station includes wide-lane, narrow-lane ambiguity resolution and the ambiguities resolution of carrier phase L1 and L2. The second method uses Kalman filtering, the C/A code and the ionosphere-free combination to solve wide-lane ambiguitie, and uses multi-path effects of the cyclical weaken multipath C/A code. The ambiguity of carrier phase on L1 band can be quickly fixed using Kalman filtering and ambiguity decorrelation algorithm based on the wide-lane ambiguity solution. The last kind of method is based on regularization principle, the thought of selected weight fitting and precisely known the reference station coordinates, to work out the regularized matrix, which can mitigate the ill-condition of the normal matrix. The relative float ambiguity can be computed only using several epochs' data. Combined with the LAMBDA method, the approach can fix the ambiguity correctly and quickly.