Precise relative positioning of multiple moving platforms using GPS carrier phase observables

Precise relative positioning of multiple moving platforms using GPS carrier phase observables has numerous applications. The essential point for this research is the fast and reliable OTF carrier phase ambiguity resolution. Algorithms for single baseline resolution cannot provide optimal performance for this application because it does not make use of the redundancy available in the configuration of multiple moving platforms.; In this thesis, a novel method called MultiKin is proposed for OTF ambiguity resolution for multiple moving platforms. First, MultiKin applies Delaunay triangulation to select necessary baselines and to build an optimal structure of ambiguity constraints. Second, it improves the reliability of the OTF ambiguity resolution of single-baselines by optimizing the ambiguity monitoring algorithm. Finally, the resolved ambiguities from each baseline are processed using the multiple triangular constraints, which can speed up fixing ambiguity and detecting wrong fixes.; To fully evaluate the performance of MultiKin, a sophisticated GPS software simulator is developed. Its significance lies in a GPS error simulator. New GPS error models are built based on the investigation of the existing models. The spatial correlation and temporal variation of errors are highlighted in the new models; thus, these models are proper for error simulation in both single-point and differential GPS systems. In addition, all the models have adjustable parameters that allow users to generate a wide range of testing conditions.; The results of extensive simulation tests and field tests with MultiKin indicate that MultiKin is effective in speeding up ambiguity resolution. The time required to fix ambiguities can be reduced by up to 67% over the single-baseline method time. Also, MultiKin increases the limit on the distance by two to three kilometres over which ambiguity resolution can be performed. An increased magnitude of the GPS errors and weaker satellite visibility can degrade the efficiency improvement of MultiKin, but it can fix more baselines than the single-baseline method even under those critical conditions. Besides improving efficiency, MultiKin can also provide higher reliability in ambiguity resolution. Its time to detect wrong fixes is reduced by up to 29% over the single-baseline method. Consequently, MultiKin increases the confidence that positioning is precise.