Özet:

Being accessible and processible of the raw GNSS data of smartphones has been an innovation for low-cost GNSS positioning studies. With the release of world’s first smartphone with dual frequency GNSS chipset Mi8 by Xiaomi in May 2018, studies on smartphone-based positioning for engineering applications have gained great momentum. Considering these development dynamics, in this study, repeatedly collected Xiaomi Mi8 dual frequency static GNSS observations for two days in two-hour time span were processed using GipsyX and RTKLIB software with epoch by epoch kinematic Precise Point Positioning (PPP) method at different satellite elevation angles, and horizontal positioning accuracies were calculated. The PPP performance of dual frequency GNSS observations collected by Xiaomi Mi8 was investigated at different satellite elevation angles. The process outputs were compared with results analyzed by relative positioning method collected simultaneously with Topcon Hiper SR geodetic receiver by considering as a reference solution. According to the results, it was noted that the horizontal positioning accuracy of RTKLIB outputs has directly inverse relationship with increasing satellite elevation angles whereas GipsyX outputs have differences in this context. In the processing of Xiaomi Mi8 dual frequency observations with PPP method, it was concluded that GipsyX produced higher horizontal positioning accuracy than RTKLIB.

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