Precise Point Positioning Method Based on Wide-lane and Narrow-lane Phase Observations and Between Satellites Single Differencing

摘要

The issue of using PPP method in position determination was formed in 1997. In most developed methods, ionospheric-free linear combination is used in order to eliminate the impact of the ionospheric delay. However, this approach does not provide the directly determination of the total value of the ambiguities, and the ambiguities for the individual signals. Therefore, in many publications methods of avoiding these deficiencies were presented and among them these ones, which use a wide-lane linear combination. This approach is however based on assumption that wide-lane combination is additional information for the ambiguities determination and does not take a part directly in the position determination process. In this paper three linear combinations were used: ionospheric-free code measurements and wide-lane and narrow-lane phase measurements. All formed equations of the observations were solved together in one calculation process, using the modified least squares method. The calculations determined: the position of the receiver, correction of the a priori value of tropospheric delay, and the phase ambiguities for individual satellites. By using wide-lane and narrow-lane combination the real values of ambiguities for the individual satellites were determined and it is not necessary to take into account ionospheric delay in observation equation processing. Furthermore, using the proposed method which is based on single differences between satellites, allows to eliminate the receiver clock errors and initial phase bias, which significantly accelerate the time convergence of position solution. All of these assumptions have been included in the developed algorithm called XPPP, which was implemented in developed by authors GPES software. This paper presents the results of position determination obtained by GPES software. For this purpose coordinates of selected EPN stations were estimated and compared to the reference values. In addition, the results of the analysis tropospheric delay and convergence time of XPPP algorithm are presented.