Development of an Airborne-Based GPR System for Landmine and IED Detection: Antenna Analysis and Intercomparison

María García Fernández,Carlos Vázquez Antuña,Guillermo Álvarez Narciandi,Yuri Álvarez López,Ana Arboleya,Fernando Las-Heras Andrés

doi:10.1109/access.2021.3112058

Abstract

Airborne-based Ground Penetrating Radar (GPR) systems have proved to be an efficient solution for safe and accurate detection of buried threats such as Improvised Explosive Devices (IEDs) and anti-personnel and anti-tank landmines. The design of these prototypes is influenced by several parameters such as the working frequency band or the maximum weight and size of the payload to be placed on board the Unmanned Aerial Vehicle (UAV). In this sense, one of the main bottlenecks found in the design of these systems is the proper selection of the GPR antenna. This contribution focuses on the analysis of different Ultra Wideband (UWB) Vivaldi antennas and their performance in the context of an airborne-based GPR system. First, the Vivaldi antennas are characterized in terms of $S_{11}$ , radiation pattern, directivity, and phase center. Next, they are placed on board the implemented airborne-based GPR prototype to assess their impact on the detection capabilities of the system. In addition, other criteria such as the weight and size of the antennas are considered to make the final selection. Finally, the selected UWB Vivaldi antennas are tested in a realistic scenario.

Highlights

The development of systems for secure and fast detection of landmines, Improvised Explosive Devices (IEDs) and UneXploded Ordnances (UXOs) is a technological challenge that has been addressed using different approaches, such as handheld detectors [1], [2], autonomous robots [3], [4], vehicle-mounted detection systems [5] and, in recent years, Unmanned Aerial Vehicles (UAVs)
Different types of sensors can be integrated within UAVs for landmine and IED detection
Dual-polarized Vivaldi antennas were tested on board the UAV in a previous measurement campaign, but the resulting Ground Penetrating Radar (GPR)-Synthetic Aperture Radar (SAR) images exhibited a dispersive response, that is, echoes corresponding to the targets were not focused in range or depth, sometimes appearing several echoes for a single target

Summary

INTRODUCTION

The development of systems for secure and fast detection of landmines, Improvised Explosive Devices (IEDs) and UneXploded Ordnances (UXOs) is a technological challenge that has been addressed using different approaches, such as handheld detectors [1], [2], autonomous robots [3], [4], vehicle-mounted detection systems [5] and, in recent years, Unmanned Aerial Vehicles (UAVs). Dual-polarized Vivaldi antennas were tested on board the UAV in a previous measurement campaign, but the resulting GPR-SAR images exhibited a dispersive response, that is, echoes corresponding to the targets were not focused in range or depth, sometimes appearing several echoes (at different depths) for a single target. That makes the analysis and identification of buried targets very difficult Due to their poor performance in terms of GPR-SAR imaging, dual-polarized Vivaldi antennas have not been included in the comparison conducted . B. SECOND VALIDATION SCENARIO Within the framework of a measurement campaign in a realistic scenario to test the prototype presented in [12] in quasi-operational conditions, it was decided to compare the performance of the large and small Vivaldi antennas again, aiming to further improve the airborne-based GPR system. The plastic bag filled with paper has a noticeable reflectivity response (Fig. 17, and Fig. 18, target (1)), which can be due to its low permittivity (the relative permittivity of paper is around εr= 2.3), with respect to the surrounding medium (soil, εr= 4)

DISCUSSION

CONCLUSIONS