Reliable positioning in dense urban environments remains challenging due to frequent GNSS signal blockage, multipath, and rapidly varying satellite geometry. While factor graph optimization (FGO)-based GNSS-IMU fusion has demonstrated strong robustness and accuracy, most formulations remain offline. In this work, we present a real-time tightly coupled GNSS-IMU FGO method that enables causal state estimation via incremental optimization with fixed-lag marginalization, and we evaluate its performance in a highly urbanized GNSS-degraded environment using the UrbanNav dataset.
Cite
@article{arxiv.2603.03556,
title = {Real-time tightly coupled GNSS and IMU integration via Factor Graph Optimization},
author = {Radu-Andrei Cioaca and Paul Irofti and Cristian Rusu and Gianluca Caparra and Andrei-Alexandru Marinache and Florin Stoican},
journal= {arXiv preprint arXiv:2603.03556},
year = {2026}
}