New GNSS precise positioning by mobilephones (original) (raw)

In Android Release N ("Nougat"), Google introduced APIs giving access to GNSS raw measurements from android smartphones. After this announcement, users will be able to log GNSS raw measurements such as GPS satellite information (C/No, azimuth, elevation if a particular satellite has been used in the PVT), NMEA sentences and PVT solution with the proper time stamp. This can open many possibilities for the single-frequency GNSS receivers, also called low-cost GNSS receiver, integrated in smartphones. An opportunity to do better and complete research with GNSS raw measurements from the singlefrequency GNSS receivers can improve the accuracies for smart mobile devices. Tens meters accuracy could be enough for most of daily navigation purposes; however, it could be better to increase it for some particular cases: usages needs higher accuracy (decimeter of accuracy) like navigation for impaired people. In this aspect, mainly, the research investigates assessment of kinematic and short session static accuracies with single frequency low-cost receivers. Additionally, shares what kind of difficulties are faced, how good the results are evaluated, when the single-frequency GNSS receiver raw measurements are processed and analyzed with well know software packages for geodetic postprocessing. To explain in detail, in the research, accuracy assessment of relative static point positioning is practiced for U-blox LEA-4T. U-blox is a single-frequency GNSS receiver that measures the pseudoranges with the C/A code only. For the research, U-blox data quality is investigated for short sessions. In this aspect, the research contains the processing and analysis of static positioning for short time periods with U-blox. Besides, RTKLIB has been tested for processing the U-blox data in short static sessions. Then, Samsung Galaxy S8 is studied as low-cost single frequency receiver with kinematic, single point positioning, DGPS and static point positioning approach. In order to log desired data in android smartphone, OruxMap, GNSS Logger, Geo++ RINEX Logger and RinexOn applications are tested. Estimated point positions in real-time by Samsung Galaxy S8 chipset from API Level 23 and estimated point positions by RTKLIB post-processing from API Level 24 are analyzed in detail.