Unmanned Aircraft System Sense-and-Avoid Integrity and Continuity Risk

This paper describes new methods to reach safety targets for sense-and-avoid sensors for unmanned aircraft systems by evaluating integrity and continuity risks. These methods can be used to set sensor requirements. The closest-point-of-approach distance and time to closest point of approach, tau, are used to measure the hazards associated with the intruder aircraft. The contribution to knowledge in this paper is a new method that uses hazard state estimates and estimate error to establish 1) the integrity risk of the sense-and-avoid system not detecting imminent loss of self-separation, and 2) the probability of false alert, the flight-path continuity risk. A sensitivity analysis evaluates the impact on integrity and continuity of sensor noise, range, and sample interval. The methods described in this paper can be used to set potential sense-and-avoid sensor requirements for unmanned aircraft system integration into the National Airspace System.