# Enabling Multi-Mission Interoperable UAS Using Data-Centric Communications
## 2 Background  
The applications of UAS technologies in the civilian scope are diverse: from traditional security and protection applications (e.g., search and rescue [4; 5; 6; 7], fighting against crime and terrorism or surveillance operations [8]), to the plethora of new and exciting applications that are offered by the emergent small-sized UAS platforms, such as agribusiness, transportation, collaborative generation of images, provision of LTE voice services, inspection of industrial premises and constructions, or control of wildlife in remote areas. Research on the utilization of UAS to support the establishment of aerial sensor networks is analyzed in [9]. The atmospheric research is another sector where UAS have also been incorporated to study atmospheric composition and its impact on weather patterns [10], to measure turbulence or other thermodynamic parameters in the atmospheric boundary layer [11; 12] or to characterize air pollution influences [13]. In general, UAS have the opportunity to evolve remote sensing applications beyond the traditional limits established by larger measurement platforms due to their potential in terms of flexibility and deployability [14]. However, despite the relevance and the increasing market opportunities for commercial UAS products in the civilian scope, there is still no consensus on an architectural design for UAS that, relying on standardized communication protocols, allows supporting interoperable UAS solutionscapable of adapting to diverse mission objectives. In fact, UAS are typically designed, manufactured, and equipped to accomplish specific missions (in many cases using proprietary technologies and protocols). Moreover, a UAV is habitually subordinated to a specific GCS, being the data exchange between them based on end-to-end connections that are preconfigured by the manufacturer in the GCS and UAV equipment. Conversely, future UAS are expected to encompass multiple UAVs and sensors of different sizes and capacities, adaptable to different civilian missions not only in terms of payload and other hardware equipment, but also in terms of software and services that should be flexibly integrated as necessary. As examples, a tactical UAV could be upgraded with different algorithms for autonomous flight control or a network of small-sized UAVs could be used to rapidly deploy a voice-over-IP/LTE infrastructure to enable emergency communications over delimited geographical areas. In this future view, aerial vehicles will efficiently and securely interoperate with multiple GCS and other mobile ground/aerial units to receive tele-command, to relay data between mission participants, and to support the real-time dissemination of telemetry information to any authorized parties. This will facilitate the exchange of information and situational awareness, ultimately improving mission effectiveness. In a growing number of mission-critical systems, people recognize the suitability of Quality of Service (QoS) enabled data-centric middleware platforms, which are able not only to feed distributed applications with the needed data flows (often high-volume and with high data rates), but also to get the whole information content in a timely manner, by respecting application-specific time constraints. For this purpose, the Object Management Group (OMG) introduced the DDS standard specification [15]. DDS adopts the publish/subscribe model (pub/sub) and implements a backbone for QoS-enabled data dissemination in a timely and dependable manner. DDS obtains interoperability with guaranteed QoS via: (i) standard language-independent interfaces; and (ii) standard transport protocols that allow DDS-based applications to dynamically interconnect, to publish/subscribe information of interest, as well as to define quality-related policies to guide and inform the QoS level negotiation process.