The Research Of High-frequency Single-epoch GNSS Kinematic Differential Positioning Technology

In recent years, four satellite navigation systems are in the rapid development. Comparing with the single system, the multi-system can effectively alleviate the shortage of visible satellites and poorly geometric structure at some moment. Because of high-precision positioning results,GNSS dynamic difference has a wide application in navigation and positioning. Although the accuracy of the single-epoch positioning is lower than that of the multi-epoch, the application of the single-epoch positioning is more extensive because of the requirements of real-time in modern measurement fields. In this paper, we study the single-epoch ambiguity solution in dynamic positioning for single-baseline measurement model.The paper mainly studies the following aspects:(1) The principle of multi-system GNSS positioning is analyzed, and the double-difference observation equation is deduced. The influence of stochastic model on the differential positioning is analyzed, and the experimental results show that these stochastic models based on the height angle and the signal-to-noise ratio are superior to the equal weight stochastic model.(2) Single-epoch ambiguity solution is researched. And a new method is proposed. Firstly, wide-lane ambiguity is researched in the range of two cycles, and then the base ambiguity is researched. The influence of signal-to-noise ratio for the wide-lane ambiguity solution is analyzed, and the results show if the SNR is better, the ambiguity will be better. And then parts ambiguity search method that based on SNR is proposed. The method of parts ambiguity search can greatly improve the efficiency and accuracy of ambiguity resolution.(3) The dynamic positioning of medium-short baseline is studied. The change of reference satellite during transferring ambiguity is analyzed, and ambiguities of the previous epoch are transferred to the current epoch by using the transfer matrix so that effectively avoid the initialization of ambiguities. This paper analyzes the method of error ambiguity and gross error based on robust estimation to effectively reduce the influence of gross error. A brief introduction about several common methods of cycle slip, and the combination of a variety of methods can effectively detect the cycle slip to improve the correctness of the transmission of ambiguity.(4) The feasibility and accuracy of the single-epoch positioning are analyzed by the measured data. And the experiment shows that the method of this paper has high accuracy and success rate of ambiguity fixed for the medium-short baseline.(5) VsursPos1.0, the software that was researched and developed by ourselves, is introduced, and the software can decode the original data of OEM format and achieve GNSS single-epoch differential positioning and speeding.