Robust, high-precision global localization is fundamental to a wide range of outdoor robotics applications. Conventional fusion methods use low-accuracy pseudorange based GNSS measurements (>>5m errors) and can only yield a coarse registration to the global earth-centered-earth-fixed (ECEF) frame. In this paper, we leverage high-precision GNSS carrier-phase positioning and aid it with local visual-inertial odometry (VIO) tracking using an extended Kalman filter (EKF) framework that better resolves the integer ambiguity concerned with GNSS carrier-phase. %to achieve centimeter-level accuracy in the ECEF frame. We also propose an algorithm for accurate GNSS-antenna-to-IMU extrinsics calibration to accurately align VIO to the ECEF frame. Together, our system achieves robust global positioning demonstrated by real-world hardware experiments in severely occluded urban canyons, and outperforms the state-of-the-art RTKLIB by a significant margin in terms of integer ambiguity solution fix rate and positioning RMSE accuracy.
@article{arxiv.2303.01291,
title = {Robust, High-Precision GNSS Carrier-Phase Positioning with Visual-Inertial Fusion},
author = {Erqun Dong and Sheroze Sheriffdeen and Shichao Yang and Jing Dong and Renzo De Nardi and Carl Ren and Xiao-Wen Chang and Xue Liu and Zijian Wang},
journal= {arXiv preprint arXiv:2303.01291},
year = {2023}
}