Empowering a Single-Frequency GNSS Receiver to Achieve High-Precision Positioning with Relative Observations

2026-06-28

AI Summary

This work addresses the challenge of achieving high-precision positioning with low-cost, single-frequency GNSS receivers, which are typically constrained by hardware limitations and the absence of base station support. The authors propose a tightly coupled multi-sensor fusion approach that integrates single-frequency carrier-phase measurements with arbitrary motion sensors—such as wheel odometry, cameras, or LiDAR—within a sliding-window factor graph framework. A virtual anchor mechanism is introduced to replace physical base stations, thereby preserving carrier-phase continuity. By incorporating robust cycle-slip detection and recovery alongside multimodal motion priors, the method achieves decimeter-level accuracy without reliance on external infrastructure. Experimental results demonstrate that the system consistently reduces positioning errors from several meters to the decimeter level across diverse real-world scenarios, offering a solution that is accurate, cost-effective, and highly robust.

Abstract

Global Navigation Satellite System (GNSS) navigation is widely used to provide absolute, outdoor positioning in field robotics. Advances in Real-Time Kinematic (RTK) technology can achieve centimeter-level accuracy, facilitating autonomous navigation tasks. However, the cost and extra infrastructure used for RTK still hinder the application and more cost-effective solutions are desired. In this letter, we present a novel tightly-coupled state estimation framework that achieves high-precision localization by using low-cost, mass-market single-frequency GNSS receivers with any relative motion sensors (e.g., wheel encoder, camera, LiDAR). We propose a sliding-window factor graph that integrates generic relative motion with global epoch-to-anchor constraints derived from continuous carrier phase tracking. To eliminate the reliance on physical base stations, we introduce a virtual anchor mechanism: upon the initial observation of a satellite, its state is locked as a virtual reference to establish global epoch-to-anchor constraints. By substituting multi-frequency hardware redundancy with single-frequency multi-modal kinematic priors and a robust cycle-slip recovery technique, our approach ensures carrier-phase integrity on cheap receivers. Extensive real-world experiments on heterogeneous low-cost sensor suites validate that our method improves the accuracy of a single-frequency receiver from several meters to decimeter-level precision across diverse environments, providing an accurate, cost-effective and reliable alternative for autonomous navigation.

Problem

• single-frequency GNSS
• high-precision positioning
• RTK
• cost-effective navigation
• autonomous navigation

Innovation

• single-frequency GNSS
• virtual anchor
• tightly-coupled estimation
• factor graph optimization
• cycle-slip recovery