UAS Integration into the National Airspace System: Modeling the Sense and Avoid Challenge

Deployed operations of unmanned aircraft systems in support of the Global War on Terrorism have established the value of this type of aircraft to effective military operations. This experience has accelerated the fielding of unmanned aircraft not only in the combat zone, but also within the continental US to support military training and homeland security missions provided by the Coast Guard and Customs and Border Protection. Complete realization of the potential of unmanned aircraft systems across the full spectrum of military and civil operations will only be met by full integration of these aircraft into the National Airspace System. The analytical environment described in this paper has resulted from experience gained during early modeling efforts beginning with the NASA Access 5 program and, most recently, participation in a series of Federal Aviation Administration workshops chartered with the goals of defining sense and avoid functional capabilities and developing a set of evaluation criteria for assessing the safety of sense and avoid solutions. The analytical environment resulting from these and other studies consists of three major modeling processes designed to define the probability of encounter during a UAS mission, describe the encounter geometry and aircraft flight characteristics given that an encounter occurs, and establish system performance requirements to ensure that the overall safety of the airspace is not compromised.