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arXiv · 2605.24980

Loosely Coupled Factor Graph Optimization for Pseudolite-Augmented Navigation

Chih-Chun Chen·Lipeng Tan·Shiyu Bai·Heike Vallery
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Abstract

In Global Navigation Satellite System (GNSS)-degraded environments, pseudolites (PLs) provide additional signal sources to enhance positioning performance, but their integration in optimization-based frameworks remains limited. This paper presents a loosely coupled factor graph optimization (FGO) framework that fuses the GNSS/PL least-squares (LS) solutions with inertial measurement unit (IMU) data. The evaluation considers low GNSS visibility scenarios with four high-elevation GNSS satellites and up to two PL transmitters over an 80~s window. FGO achieves a 22.8\% to 41.3\% reduction in mean 3D error compared to standard LS methods. Compared to a GNSS-IMU baseline, incorporating PL transmitters further improves positioning accuracy, with performance depending on geometry.

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Chih-Chun Chen, Lipeng Tan, Shiyu Bai, Heike Vallery. 2026-05-24. Loosely Coupled Factor Graph Optimization for Pseudolite-Augmented Navigation. https://arxiv.org/abs/2605.24980

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