Long Duration Inspection of GNSS-Denied Environments with a Tethered UAV-UGV Marsupial System

2025-05-29

AI Summary

To address the challenges of limited endurance and unreliable localization for UAVs in GNSS-denied environments, this paper proposes a tethered marsupial cooperative system comprising a tethered UAV and a ground robot (UGV), interconnected via a physical tether enabling continuous power supply and coordinated control. We introduce Direct LiDAR Localization (DLL), a novel GNSS-free method enabling high-precision autonomous localization and tightly coupled trajectory tracking. The system integrates LiDAR-based SLAM, safety-aware path planning, and a multi-body dynamics–aware coupled controller within a full-stack ROS software framework. Experimental results demonstrate significantly extended operational endurance. The system exhibits strong robustness and practicality across three real-world validation scenarios: manual endurance testing, autonomous navigation, and end-to-end inspection. This work establishes a new paradigm for long-duration, fully autonomous inspection in satellite-denied settings.

Technology Category

• Intelligent Robots: Localization, Mapping, and Navigation
• Multiagent Systems: Teamwork
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search

Abstract

Unmanned Aerial Vehicles (UAVs) have become essential tools in inspection and emergency response operations due to their high maneuverability and ability to access hard-to-reach areas. However, their limited battery life significantly restricts their use in long-duration missions. This paper presents a novel tethered marsupial robotic system composed of a UAV and an Unmanned Ground Vehicle (UGV), specifically designed for autonomous, long-duration inspection tasks in Global Navigation Satellite System (GNSS)-denied environments. The system extends the UAV's operational time by supplying power through a tether connected to high-capacity battery packs carried by the UGV. We detail the hardware architecture based on off-the-shelf components to ensure replicability and describe our full-stack software framework, which is composed of open-source components and built upon the Robot Operating System (ROS). The proposed software architecture enables precise localization using a Direct LiDAR Localization (DLL) method and ensures safe path planning and coordinated trajectory tracking for the integrated UGV-tether-UAV system. We validate the system through three field experiments: (1) a manual flight endurance test to estimate the operational duration, (2) an autonomous navigation test, and (3) an inspection mission to demonstrate autonomous inspection capabilities. Experimental results confirm the robustness and autonomy of the system, its capacity to operate in GNSS-denied environments, and its potential for long-endurance, autonomous inspection and monitoring tasks.

Problem

• Enables long-duration UAV inspection in GNSS-denied environments
• Extends UAV battery life via tethered UGV power supply
• Ensures autonomous localization and navigation without GNSS signals

Innovation

• Tethered UAV-UGV system for extended operation
• Direct LiDAR Localization in GNSS-denied areas
• Open-source ROS-based full-stack software framework