Differential GNSS and Vision-Based Tracking to Improve Navigation Performance in Cooperative Multi-UAV Systems

Amedeo Vetrella,Domenico Accardo,Antonio Moccia,Giancarmine Fasano

doi:10.3390/s16122164

Abstract

Autonomous navigation of micro-UAVs is typically based on the integration of low cost Global Navigation Satellite System (GNSS) receivers and Micro-Electro-Mechanical Systems (MEMS)-based inertial and magnetic sensors to stabilize and control the flight. The resulting navigation performance in terms of position and attitude accuracy may not suffice for other mission needs, such as the ones relevant to fine sensor pointing. In this framework, this paper presents a cooperative UAV navigation algorithm that allows a chief vehicle, equipped with inertial and magnetic sensors, a Global Positioning System (GPS) receiver, and a vision system, to improve its navigation performance (in real time or in the post processing phase) exploiting formation flying deputy vehicles equipped with GPS receivers. The focus is set on outdoor environments and the key concept is to exploit differential GPS among vehicles and vision-based tracking (DGPS/Vision) to build a virtual additional navigation sensor whose information is then integrated in a sensor fusion algorithm based on an Extended Kalman Filter. The developed concept and processing architecture are described, with a focus on DGPS/Vision attitude determination algorithm. Performance assessment is carried out on the basis of both numerical simulations and flight tests. In the latter ones, navigation estimates derived from the DGPS/Vision approach are compared with those provided by the onboard autopilot system of a customized quadrotor. The analysis shows the potential of the developed approach, mainly deriving from the possibility to exploit magnetic- and inertial-independent accurate attitude information.

Highlights

Micro-UAS can play a key role in several civil scenarios, and the attention of international top level companies and research centers has been focused on the adoption of these systems for commercial purposes [1,2] and on the paradigms for a safe and profitable access of micro-unmanned aerial vehicles to civil airspace [3,4]
This paper presents a new approach to improve the absolute navigation performance of a formation of UAVs flying in outdoor environments under nominal Global Positioning System (GPS) coverage, with respect to the one achievable by integrating low cost Inertial Measurement Units (IMUs), Global Navigation Satellite System (GNSS) and magnetometers
Cooperation is here exploited to improve the absolute navigation performance of formation flying UAVs in outdoor environments. This is done thanks to an architecture that integrates differential GPS and relative sensing by vision within a customized sensor fusion algorithm

Summary

Introduction

In the last few years, miniaturization of flight control systems and payloads, and the availability of computationally affordable algorithms for autonomous guidance, navigation and control (GNC), have contributed to an increasing diffusion of micro-unmanned aircraft systems (micro-UAS).Besides military applications, micro-UAS can play a key role in several civil scenarios, and the attention of international top level companies and research centers has been focused on the adoption of these systems for commercial purposes [1,2] and on the paradigms for a safe and profitable access of micro-unmanned aerial vehicles (micro-UAVs) to civil airspace [3,4].Micro-UAV navigation is typically based on the integration of low cost GNSS receivers and commercial grade Micro-Electro-Mechanical Systems (MEMS)-based inertial and magnetic sensors.An extensive review of techniques based on the integration of low cost Inertial Measurement Units (IMUs) and GNSS can be found in [5]. Micro-UAS can play a key role in several civil scenarios, and the attention of international top level companies and research centers has been focused on the adoption of these systems for commercial purposes [1,2] and on the paradigms for a safe and profitable access of micro-unmanned aerial vehicles (micro-UAVs) to civil airspace [3,4]. Micro-UAV navigation is typically based on the integration of low cost GNSS receivers and commercial grade Micro-Electro-Mechanical Systems (MEMS)-based inertial and magnetic sensors. An extensive review of techniques based on the integration of low cost Inertial Measurement Units (IMUs) and GNSS can be found in [5].

Objectives

Results

Conclusion