GraphGNSSLib

An Open-source Package for GNSS Positioning and Real-time Kinematic Using Factor Graph Optimization

This repository is the implementation of the open-sourced package, the GraphGNSSLib, which makes use of the factor graph optimization (FGO) to perform the postprocessing of GNSS positioning and real-time kinematic (RTK) positioning. In this package, measurements from the historical and current epochs are structured into a factor graph which is then solved by non-linear optimization. The package is based on C++ which is compatible with the robot operation system (ROS) platform. Meanwhile, this package combines the RTKLIB (version: 2.4.3 b33) to read/decode the GNSS RINEX files. Users from Robotics field can easily have access to GNSS raw data for further study. We are still improving the code readibility with the hope that this package can benefit the research community.

Important Notes:

• Be noted that the GNSS Positioning mentioned throughout the package means estimating the positioing of the GNSS receiver based on the combination of pseudorange and Doppler measurements uisng FGO.
• Be noted that the GNSS-RTK Positioning mentioned throughout the package means estimating the positioing (float solution) of the GNSS receiver based on the combination of double-differenced pseudorange, carrier-phase and the Doppler measurements using FGO. Finally, the ambiguity is resolved using LAMBDA algorithm via epoch-by-epoch manner.
• An very interesting article illustrating the advantage and potential of the FGO in GNSS positioning, see What is a factor graph?.