Optimizing the Use of RTKLIB for Smartphone-Based GNSS Measurements

Area of Science:

• Geomatics Engineering
• Mobile Sensing
• Satellite Navigation

Background:

• The Google Smartphone Decimeter Challenge (GSDC) aimed to assess the accuracy of Global Navigation Satellite System (GNSS) positioning using Android smartphones.
• RTKLIB, an open-source GNSS processing tool, offers Post-Processed Kinematic (PPK) solutions but was originally designed for geodetic receivers, not smartphones.
• Smartphone GNSS measurements exhibit lower quality compared to geodetic receivers, posing challenges for achieving high-accuracy positioning.

Purpose of the Study:

• To optimize the performance of RTKLIB for processing GNSS data from Android smartphones.
• To adapt RTKLIB's codebase and default settings for the specific characteristics of mobile phone measurements.
• To evaluate the effectiveness of these optimizations in the context of the GSDC competition.

Main Methods:

• Focused on the Post-Processed Kinematic (PPK) capabilities of RTKLIB for analyzing historical GSDC data.
• Implemented modifications to RTKLIB's codebase and adjusted default processing parameters.
• Documented the specific changes and provided steps for replication of the results.

Main Results:

• The optimized RTKLIB achieved a 5th place ranking in the GSDC competition based on its performance.
• Adjustments successfully addressed limitations of the original RTKLIB when applied to lower-quality smartphone GNSS data.
• The enhanced codebase and methodology provide a foundation for future improvements in smartphone-based positioning.

Conclusions:

• RTKLIB can be effectively optimized for Android smartphone GNSS measurements through code and setting adjustments.
• The modifications are crucial for overcoming the inherent quality differences between smartphone and geodetic receivers.
• This work offers a practical procedure for improving smartphone-based positioning accuracy and serves as a benchmark for future challenges.