The algorithm of multi-frequency carrier phase integer ambiguity resolution with GPS/BDS between long range network RTK reference stations

The method of long range network RTK is the main means to improve the accuracy of real-time kinematic positioning of GPS/BDS. The fast fixing of carrier phase integer ambiguity with GPS/BDS between long range reference stations was significant. The algorithm of multi-frequency carrier phase integer ambiguity resolution with GPS/BDS between long range network RTK reference stations was studied in this paper. The GPS wide-lane ambiguities were fixed by the double frequency observation data of reference station network. And the extra-wide-lane ambiguities of B2 and B3 frequency were fixed by using B2 and B3 frequency observation data at the same time. Then the solution model including GPS double difference carrier phase integer ambiguities and atmospheric errors can be established, the carrier phase integer ambiguity can be fixed by this solution model and the constraint of wide-lane ambiguities. Then the spatial correlation model of atmospheric delay error was established. And the computation model of BDS double difference carrier phase integer ambiguity including atmospheric delay error was established by the extra-wide-lane ambiguities of B2 and B3 frequency. The BDS carrier phase integer ambiguity resolution was constrained by the spatial correlation model of atmospheric errors. Therefore the influence of ambiguities fixing by using ionosphere free observation can be eliminated. The test of the algorithm was carried out by the GPS/BDS data with long range reference station network. The results of experiment indicate that the rapidly fixing of carrier phase integer ambiguity with GPS/BDS between long range reference stations was achieved by this algorithm.