Rapidly increasing growth and demand in various Unmanned Aircraft Systems (UAS) have pushed governmental regulation development and numerous technology research activities toward integrating unmanned and manned aircraft into the same civil airspace. Safety of other airspace users is the primary concern; thus, with the introduction of UAS into the National Airspace System (NAS), a key issue to overcome is the risk of a collision with manned aircraft. The challenge of UAV integration is global. In this paper, the authors present the operational concept and benefits of an airborne collision system for UAS based on a modified automatic dependent surveillance - broadcast (ADS-B) system, a promising technology under development globally. With the affordable Universal Access Transceiver (UAT) Beacon Radio developed by The MITRE Corporation and the hybrid estimation approach for resource-limited UAS, the ADS-B radar concept appears to be an economically viable solution to detect both cooperative and non-cooperative targets using a single avionics package.