Application of ADS-B for unmanned aerial systems: Case study and practical approach

The National Airspace System (NAS) has experienced rapid growth in unmanned aircraft system (UAS) use and demand for airspace access. Expanding UAS military and civilian applications result in increasing demand for NAS access. It is driving the need for researches on UAS operations and air traffic management in a safe and effective manner. The ability for an unmanned aircraft to “sense and avoid” is the primary and pressing technical challenge. Sense and Avoid Systems (SAAS) have been perceived as potential solution for conflict detection and air traffic collisions avoidance, but the technical implementations for UAS have been far from satisfaction. One possible method for the SAAS to continuously localize surrounding aircraft and obtain traffic information necessary for integrating UAS may be through Automatic Dependent Surveillance-Broadcast (ADS-B). It is one of the most potential tracking technologies in Next Generation Air Transportation System (NextGen) to improve situational awareness for pilots. This paper examines the use of ADS-B system in future SAAS, possible implementations for UAS towards infrastructures, data link communication capabilities and satellite communication abilities. The technical challenges and safety concerns associated with UAS integration are presented. Finally, a practical approach of ADS-B unit for UAS based on soft defined radio in support with satellite relay and dynamic data link switch is discussed and developed.