Visual Cooperative Drone Tracking for Open-Path Gas Measurements

2026-02-24

AI Summary

This work proposes a cooperative system comprising a ground-based laser sensor and an unmanned aerial vehicle (UAV) equipped with a retroreflector to overcome the limitations of conventional open-path gas sensing, which typically relies on fixed reflectors and lacks spatial flexibility. For the first time, the system integrates visual servoing—based on tracking LED markers—with GNSS positioning to enable autonomous laser beam alignment and non-intrusive, long-range gas monitoring. By combining tunable diode laser absorption spectroscopy with gas tomography algorithms, the platform successfully performs autonomous CO₂ concentration measurements over a 60-meter path, accurately capturing CO₂ plumes without interference from the UAV’s propulsion system. This approach significantly enhances the flexibility and robustness of open-path gas sensing in dynamic environments.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Computer Vision: Remote Sensing / Geospatial AI
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Sustainability and carbon-aware systems for Web, mobile, and WoT
• Security and Privacy: Data transparency and provenance
• Responsible Web: Machine-in-the-loop, human agency and autonomy

Abstract

Open-path Tunable Diode Laser Absorption Spectroscopy offers an effective method for measuring, mapping, and monitoring gas concentrations, such as leaking CO2 or methane. Compared to spatial sampling of gas distributions using in-situ sensors, open-path sensors in combination with gas tomography algorithms can cover large outdoor environments faster in a non-invasive way. However, the requirement of a dedicated reflection surface for the open-path laser makes automating the spatial sampling process challenging. This publication presents a robotic system for collecting open-path measurements, making use of a sensor mounted on a ground-based pan-tilt unit and a small drone carrying a reflector. By means of a zoom camera, the ground unit visually tracks red LED markers mounted on the drone and aligns the sensor's laser beam with the reflector. Incorporating GNSS position information provided by the drone's flight controller further improves the tracking approach. Outdoor experiments validated the system's performance, demonstrating successful autonomous tracking and valid CO2 measurements at distances up to 60 meters. Furthermore, the system successfully measured a CO2 plume without interference from the drone's propulsion system, demonstrating its superiority compared to flying in-situ sensors.

Problem

• open-path gas measurement
• automated spatial sampling
• reflector requirement
• gas concentration monitoring
• Tunable Diode Laser Absorption Spectroscopy

Innovation

• Visual tracking
• Cooperative drone system
• Open-path TDLAS
• Gas tomography
• Autonomous alignment