3rd Place Winner: 2022 Smartphone Decimeter Challenge: An RTKLIB Open-Source Based Solution

This paper describes a demonstration of the open-source RTKLIB software as used to compete in the 2022 Google smartphone decimeter challenge (GSDC). The GSDC is a competition where raw GNSS observation data from Android smartphones is provided to be processed to generate the most accurate determination of longitude and latitude. This solution is based on the capability of RTKLIB to run post-processed kinematic (PPK) solutions on raw GNSS observation data. The goals of this effort were to demonstrate the capability of the RTKLIB software to provide comparatively high accuracy solutions for smartphone data, to provide an easily reproducible result that can be used as a starting point for other GNSS research, and to set a benchmark for a conventional solution with incremental improvement that can be used to help assess the effectiveness of more novel approaches from other competitors. Although PPK positioning solutions are expected to provide centimeter level accuracy when used with high quality data from commercial GNSS receivers, the lower quality of the Android measurements means this level of accuracy is difficult or impossible to achieve. Additionally, the default configurations and methodologies of the RTKLIB solutions are optimized for higher quality measurements. Hence, multiple changes were required to both the RTKLIB code and configuration files to optimize the solutions for smartphone measurements. Previously it was demonstrated, after the 2021 GSDC challenge had completed, that a version of RTKLIB optimized for smartphone measurements would have resulted in a fifth place finish in that competition. This paper uses that solution as a starting point and extends it to further improve position accuracy for this year’s data. These results achieved sixth place in the 2022 competition and a more recent variation of this solution achieved a score within 1 cm of the third place solution.