Dynamic logic selection for unmanned aircraft separation

The ACAS Xu program has developed both a horizontal and vertical collision avoidance logic to enable unmanned aircraft to avoid manned aircraft. Each logic supports a variety of surveillance sources and is individually capable of providing a significant safety benefit. This paper proposes a logic selection function that can effectively arbitrate between the horizontal and vertical logics to achieve an overall safety benefit without requiring the use of simultaneous horizontal and vertical maneuvers. Monte Carlo simulations show that the logic selection function can provide a performance benefit for a variety of surveillance sources.