| With the development of times and the improvement of science and technology, the revolutionary changes of measurement have taken place. Global Positioning System (GPS) is the technology that complies with the demand of the era of development. As the hot research direction of GPS Navigation and Positioning System, the theory and technology of kinematic precise point positioning (KPPP) has also become more mature. Especially after the International GNSS Service (IGS) releases the precise satellite orbits products and precise satellite clock correction, more and more attentions to this area as its wide application also makes it have wide development prospects. Compared with the difference method, some systematic errors cannot be eliminated with the un-differenced data that collected only by a single GPS receiver. As the error correction model is still not perfect, and influenced by many other unknown factors, accuracy of kinematic precise point positioning remains to be improved.By constraining the trajectories of receiver, this thesis uses Kalman filter with the constraint equation to improve kinematic precise point positioning accuracy. In this thesis, additional constraints include two ways that receiver moves along a straight line and in a plane. This thesis uses ionosphere-free model with precise satellite orbits products and precise satellite clock correction published by IGS. The solutions with constraints or not are contrasted with the results of reference station by double-differenced data to get the outside precision of two experiments. The experimental results show that positioning along a straight line accuracy has improved obviously. Under the restriction of planar constraints the accuracy has also improved, but it still influenced by other factors, which needed more experiments to explore the reasons in the future. In general, kinematic precise point positioning, which add the trajectory of additional constraints in the receiver, could improve the accuracy in positioning. |
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