This repository is a small set of custom factors and MATLAB wrappers that use GTSAM for GNSS processing.

This repository is currently under development, so we will gradually add content.

Updates

February 13, 2025

The preprint of the paper has been uploaded. Examples in the paper are now available. Also, examples of the use of CarrierPhaseFactor_XB to estimate carrier phase integer ambiguity have been added.

Test environments

• Ubuntu 22.04 / Windows 11 /macOS
• MATLAB 2024a

Build on Ubuntu 22.04

GTSAM

• GTSAM: Factor graph optimization library. Due to a problem with the MATLAB wrapper, please clone GTSAM from my repository instead of the original GTSAM and build it using the following procedure.

sudo apt-get install -y git build-essential cmake libboost-all-dev libtbb-dev python3-pip
pip install pyparsing
git clone https://github.com/taroz/gtsam-4.3a.git
cd gtsam-4.3a
mkdir build && cd build
cmake .. -DGTSAM_BUILD_UNSTABLE=OFF -DGTSAM_BUILD_EXAMPLES_ALWAYS=OFF -DGTSAM_BUILD_TESTS=OFF -DGTSAM_INSTALL_MATLAB_TOOLBOX=ON
make -j$(nproc)
sudo make install

gtsam_toolbox is installed in /usr/local/

gtsam_gnss

git clone https://github.com/taroz/gtsam_gnss.git
cd gtsam_gnss
mkdir build && cd build
cmake ..
make
sudo make install
sudo ldconfig

By default, gtsam_gnss is installed in user/local/gtsam_toolbox. Add user/local/gtsam_toolbox to your MATLAB search path.

Build on Windows 11

Building GTSAM and gtsam_gnss on Windows is a little complicated. The procedure is shown here.

Build on macOS

The procedure for building GTSAM and gtsam_gnss on macOS is shown here.

Examples

• See examples directory
• Use in the Google Smartphone Decimeter Challenge. See gsdc2023 repository

Citation

The preprint version is here.

T. Suzuki, "Open-Source Factor Graph Optimization Package for GNSS: Examples and Applications," 2025 IEEE/ION Position, Location and Navigation Symposium (PLANS), (accepted)