An Approach to Assess the Safety of ADS-B-based Unmanned Aerial Systems: Data Integrity as a Safety Issue

The increasing demand for the use of unmanned aerial systems (UAS) in various social and economic applications has pressed aviation authorities to draw up rules and regulations in order to allow such aircraft to fly in non-segregated airspace. However, issues related to the safety of air traffic operations arise when considering the possibility of both manned and unmanned aircraft coexisting. Thus, surveillance plays a key role in monitoring and controlling air traffic in new scenarios. The positional information provided by the Automatic Dependent Surveillance - Broadcast (ADS-B), originally designed to improve situational awareness for pilots and support controllers in air traffic management, interacts with the Sense and Avoid Systems (S&AS) of the UAS in order to avoid exposure to events of loss of minima separation distances and collisions. As positional information is essential to UASs control systems operation, parameters such as accuracy and integrity reflect the correctness and trustworthiness of this information. This paper presents a qualitative approach to assess safety when using ADS-B systems integrated with UASs in aeronautical operations considering the influence of data integrity as a safety-related parameter. In addition, the possibility of using a methodology previously applied on manned systems for assessing safety on UASs is discussed. A new testing platform (PIpE-SEC) is presented as a possible approach for this safety evaluation.