# Enabling Multi-Mission Interoperable UAS Using Data-Centric Communications
###### Abstract  
We claim the strong potential of data-centric communications in Unmanned Aircraft Systems (UAS), as a suitable paradigm to enhance collaborative operations via efficient information sharing, as well as to build systems supporting flexible mission objectives. In particular, this paper analyzes the primary contributions to data dissemination in UAS that can be given by the Data Distribution Service (DDS) open standard, as a solid and industry-mature data-centric technology. Our study is not restricted to traditional UAS where a set of Unmanned Aerial Vehicles (UAVs) transmit data to the ground station that controls them. Instead, we contemplate flexible UAS deployments with multiple UAV units of different sizes and capacities, which are interconnected to form an aerial communication network, enabling the provision of value-added services over a delimited geographical area. In addition, the paper outlines an approach to address the issues inherent to the utilization of network-level multicast, a baseline technology in DDS, in the considered UAS deployments. We complete our analysis with a practical experience aiming at validating the feasibility and the advantages of using DDS in a multi-UAV deployment scenario. For this purpose, we use a UAS testbed built up by heterogeneous hardware equipment, including a number of interconnected micro aerial vehicles, carrying single board computers as payload, as well as real equipment from a tactical UAS from the Spanish Ministry of Defense. Unmanned Aircraft Systems (UAS); network of Unmanned Aerial Vehicles (UAVs); data-centric communications; Data Distribution Service (DDS) 2018 18 3421 10 October 2018 12 October 2018 18 3421 10 Octoberacquisition unit, being transmitted as telemetry information towards the GCS, where it is inspected and/or analyzed. Analogously, tele-command (i.e., the control information transmitted from the GCS to the UAV) enables the execution of control operations over the aircraft, such as changing the route planning or the direction pointed by a camera. Communications between the GCS and the UAVs take place over wireless data-links, e.g., based on a radio line-of-sight technology, Wi-Fi or 3G/4G. UAVs may also have redundant links to maintain communications in long-range missions (e.g., satellite). The industry has given the first steps towards evolved UAS architectures and communication models. The utilization of data-centric approaches represents a promising line in this direction, where information is named and decoupled from its location, and applications/services operate over these named data rather than on host-to-host communications. The Data Distribution Service (DDS), overviewed in Section 3, has emerged as an industry-oriented open standard that follows this approach. Being designed for mission and business critical applications, the potential benefits of DDS have motivated its appearance in specific commercial UAS solutions (e.g., in Insitu [1] and General Atomics [2] air vehicle products). In this paper, we study the potential advantages of using the DDS, as an industry standard solution, to enable adaptable and interoperable UAS products. As opposed to existing commercial UAS solutions, in our work, we consider deployment scenarios where a UAS is conformed by multiple UAV units, which are interconnected to support the provision of end-to-end value added services over the geographical area covered by the deployment. Following the DDS standard, these services would easily be integrated into different UAV units, being accessible on-demand to authorized parties (e.g., ground mobile stations with access connectivity to the aerial network formed by the UAVs) through the standard mechanisms defined by DDS. In the paper, we carry out an analysis of the advantages and limitations of using DDS in the UAS deployments under consideration, using a set of motivating scenarios.