Synchronous Observer Design for Landmark-Inertial SLAM with Magnetometer and Intermittent GNSS Measurements

2026-04-06

AI Summary

This work addresses the inherent unobservability in Landmark-Inertial SLAM (LI-SLAM), which prevents estimation of the robot’s and landmarks’ absolute positions and yaw orientation in the inertial frame, leading to incomplete state recovery. To overcome this limitation, the paper proposes a novel nonlinear synchronous observer that, for the first time, integrates magnetometer readings and intermittent GNSS position measurements into the LI-SLAM framework, enabling joint estimation of the full state—including absolute position and yaw. Leveraging Lyapunov stability theory, the authors rigorously establish that the resulting estimation error dynamics are almost globally asymptotically stable and locally exponentially stable. Comprehensive simulations demonstrate the effectiveness and robustness of the proposed approach in fusing heterogeneous sensor data from IMUs, visual landmarks, magnetometers, and GNSS.

Abstract

In Landmark-Inertial Simultaneous Localisation and Mapping (LI-SLAM), the positions of landmarks in the environment and the robot's pose relative to these landmarks are estimated using landmark position measurements, and measurements from the Inertial Measurement Unit (IMU). However, the robot and landmark positions in the inertial frame, and the yaw of the robot, are not observable in LI-SLAM. This paper proposes a nonlinear observer for LI-SLAM that overcomes the observability constraints with the addition of intermittent GNSS position and magnetometer measurements. The full-state error dynamics of the proposed observer is shown to be both almost-globally asymptotically stable and locally exponentially stable, and this is validated using simulations.

Problem

• LI-SLAM
• observability
• inertial frame
• yaw estimation
• state estimation

Innovation

• nonlinear observer
• Landmark-Inertial SLAM
• intermittent GNSS
• magnetometer
• observability