Development and Experimental Evaluation of a Low-Cost Cooperative UAV Localization Network Prototype

Abstract

Precise localization is one of the key requirements in the deployment of UAVs (Unmanned Aerial Vehicles) for any application including precision mapping, surveillance, assisted navigation, search and rescue. The need for precise positioning is even more relevant with the increasing automation in UAVs and growing interest in commercial UAV applications such as transport and delivery. In the near future, the airspace is expected to be occupied with a large number of unmanned as well as manned aircraft, a majority of which are expected to be operating autonomously. This paper develops a new cooperative localization prototype that utilizes information sharing among UAVs and static anchor nodes for precise positioning of the UAVs. The UAVs are retrofitted with low-cost sensors including a camera, GPS receiver, UWB (Ultra Wide Band) radio and low-cost inertial sensors. The performance of the low-cost prototype is evaluated in real-world conditions in partially and obscured GNSS (Global Navigation Satellite Systems) environments. The performance is analyzed for both centralized and distributed cooperative network designs. It is demonstrated that the developed system is capable of achieving navigation grade (2-4 m) accuracy in partially GNSS denied environments, provided a consistent communication in the cooperative network is available. Furthermore, this paper provides experimental validation that information sharing is beneficial to improve positioning performance even in ideal GNSS environments. The experiments demonstrate that the major challenges for low-cost cooperative networks are consistent connectivity among UAV platforms and sensor synchronization.

Robust Positioning Performance in Indoor Environments

“…For example, at time instants 2.62 x 10 4 s and 2.8 x 10 4 s, sudden jumps in the range observations are visible. This is most likely because of multipath in indoor environment in the UWB observations [5]. Similar corruption by the outliers in the ranges derived from UWBs in complex environments has been previously reported by authors in [4,5].…”

“…This is most likely because of multipath in indoor environment in the UWB observations [5]. Similar corruption by the outliers in the ranges derived from UWBs in complex environments has been previously reported by authors in [4,5]. Such outliers should be accounted for, within the cooperative state estimation framework.…”

“…Such outliers should be accounted for, within the cooperative state estimation framework. One such framework for incorporating corrupted UWB range measurements in a cooperative estimation framework is presented by authors in [5]. Further, it is interesting to observe that the nature of the UWB signals observed by both the pedestrians are very similar.…”

Special Issue: Localization in Wireless Sensor Networks

“…Published works in the Special Issue cover a wide range of topics, namely development of a prototype of a new cooperative unmanned aerial vehicles (UAV) swarm localization system using low-cost sensors and cameras [1], lightweight distributed localization schemes for energy-restricted WSNs [2], fabrication of additional (angle) information for aiding tracking performance [3], target localization using combined radio measurements in the presence of synchronization errors [4], performance comparison of existing algorithms for hyperbolic 3-dimensional localization [5], and characterization of the log-normal model for received signal strength (RSS) measurements [6]. A short overview of each of the above-mentioned works is provided in the following.…”

“…In [1], Goel et al developed a novel cooperative localization prototype based on information sharing among UAVs and static anchor nodes for precise localization of the UAVs. The UAVs were retrofitted with low-cost sensors including a camera, GPS receiver, UWB radio, and low-cost inertial sensors.…”