Autonomous localization of multiple ionizing radiation sources using miniature single-layer Compton cameras onboard a group of micro aerial vehicles

TL;DR

This paper introduces a lightweight, real-time method for autonomous localization of multiple gamma radiation sources using a fleet of micro aerial vehicles equipped with miniature Compton cameras, enhancing rapid environmental mapping.

Contribution

It presents a novel multi-MAV radiation mapping approach utilizing Compton cameras that reconstruct source directions from single particles, enabling fast, gradient-free localization.

Findings

Effective in simulation and real-world tests with Cesium-137 sources.

Achieves accurate source localization without gradient estimation.

Enhances exploration speed with active search strategy.

Abstract

A novel method for autonomous localization of multiple sources of gamma radiation using a group of Micro Aerial Vehicles (MAVs) is presented in this paper. The method utilizes an extremely lightweight (44 g) Compton camera MiniPIX TPX3. The compact size of the detector allows for deployment onboard safe and agile small-scale Unmanned Aerial Vehicles (UAVs). The proposed radiation mapping approach fuses measurements from multiple distributed Compton camera sensors to accurately estimate the positions of multiple radioactive sources in real time. Unlike commonly used intensity-based detectors, the Compton camera reconstructs the set of possible directions towards a radiation source from just a single ionizing particle. Therefore, the proposed approach can localize radiation sources without having to estimate the gradient of a radiation field or contour lines, which require longer measurements. The instant estimation is able to fully exploit the potential of highly mobile MAVs. The radiation mapping method is combined with an active search strategy, which coordinates the future actions of the MAVs in order to improve the quality of the estimate of the sources' positions, as well as to explore the area of interest faster. The proposed solution is evaluated in simulation and real world experiments with multiple Cesium-137 radiation sources.