Triple frequency cascading ambiguity resolution for modernized GPS and GALILEO.

摘要

Both modernized GPS and GALILEO will have three frequencies modulated with three signals, all of which will be accessible to all users in the near future.; This thesis starts with the investigations on the linear combinations (LC) rising from the triple frequencies of the two systems, some of which show potential benefits in carrier phase integer ambiguity resolution. For each system, a set of combinations with stepwise wavelengths (GPS: 0.190, 0.862 and 5.861 m; GALILEO: 0.190, 0.814 and 9.768 m) were fully studied, analyzed, and then selected in the development of a GPS/GALILEO triple frequency cascading ambiguity resolution (CAR) method involving the Least-squares Ambiguity Decorrelation Adjustment (LAMBDA).; The performance analysis of a basic CAR under error condition of measurement noise level was first conducted to set a baseline for the application of CAR. Further efforts were spent to the last step of the CAR to deal with the gradually increased residual measurement errors by integrating various models---such as geometry-free/based integer ambiguity model, ionosphere-free and stochastic ionosphere models, and etc.; Tests, analysis and comparison of the algorithms were made in simulated scenarios of the two systems under error conditions of typical multipath, troposphere, medium and high ionosphere over 1 to 70 km baselines, followed by final conclusions and suggestions for future work.