Experimental Results of UAS Localization and Tracking by Passive TDoA

This paper introduces the design, efficient implementation, and experimental validation of a Time Difference of Arrival (TDoA)-based localization system for real-time positioning of small Unmanned Aerial Systems (UAS) in an area spanning approximately 300 acres. Leveraging commercial-off-the-shelf (COTS) components such as an affordable software-defined radio (SDR) receiver and a Blade RF, the system attains real-time position estimation, where 90% of the localization errors were less than 5 meters. Additionally, the system exhibits a median latency of 1.3 seconds. To the best of our knowledge, this is the first study that showcases real-time field-experimental results that move away from Matlab-based simulations, for passive RF TDoA localization of UAS. The proposed methodology is versatile, suitable for a range of localization scenarios such as security, cyber radio-frequency (RF), and search-and-rescue (SAR) applications.

I. Introduction

The localization of wireless (active) emitters plays a significant role in security, cyber radio-frequency (RF) [1] and search-and-rescue (SAR) applications [2]. Practical localization methods are based on radio-frequency (RF) [2], acoustical [3], and optical [4] approaches. In RF, active radar is widespread, while passive RF localization is mainly used by governments (military / police) due to the challenging combination of multi-disciplinary constraints. On one hand, it requires a strong background in signal processing (e.g., estimation theory and linear algebra) and wireless communication protocols. On the other, for implementation, it requires expensive, regulated proprietary hardware and heavy infrastructure (e.g., communication and electricity). Given the proliferation of software-defined-radio (SDR) over the last years, it has become more available for commercial use, and the entry barrier is primarily related to the ability to efficiently run sophisticated algorithms on the SDR.