A.N. Podkorytov – Ph.D. (Eng.), Associate Professor; Head of Sector,

Moscow Aviation Institute (National Research University);

JSC «Russian Space Systems»

E-mail: thepompous@gmail.com

Network solution and user solution for precise point positioning in global navigation satellite systems are considered in the study. By network solution processing data from a set of stations with known geographic coordinates is meant.  GPS ionosphere-free observation model with decoupled clocks is used in the work for applying the procedure of ambiguity resolution of phase measurements. Satellite decoupled clocks for such ionosphere-free observation model are computed in six different variants of network solution and called as network products. The author considers 4 different variants of network solution based on European stations from a network of International GNSS service. The number of stations of International GNSS service network in Russia is extremely low, so the other two variants of network solution are based on stations from a network of Russian satellite based augmentation system. Considered variants of network solution are varied in number of stations, general surface, receiver types, configuration and measurements quality. User solution is precise point positioning with use of network products available from network solution. Network products computed in different variants of network solution are then used for user solution with applying the procedure of ambiguity resolution of phase measurements in various points of considered networks. The influence of network structure on accuracy and convergence time of precise point positioning with ambiguity resolution of phase measurements is analyzed. The properties of network structure are listed and described. The most important of them is the use of homogeneous stations. This requirement includes unity of hardware, firmware version and types of collected measurements. On the one side, extending of network increases the number of observed satellites, on the other hand, it becomes more difficult to provide network stations to be homogeneous. To the current time the procedure of ambiguity resolution is not stable yet, so positioning results may vary for different points and time intervals inside a network. For this reason precise point positioning results are averaged for 5 different stations and for 5…50 minutes intervals. Nevertheless, averaged results of precise point positioning with ambiguity resolution are still better than precise point positioning results with use of traditional ionosphere-free observation model.

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