A method includes receiving, by a computing system, a first authenticated signal that (i) identifies a first position of a first aircraft relative to a host aircraft on which the computing system is located and (ii) includes a first identifier of the first aircraft, receiving, at a subsequent time, a second signal that is an ADS-B signal that identifies a second position, a velocity, and an aircraft type, where the second signal includes a second identifier, based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, using the first position and the aircraft type to confirm that it is possible that the first aircraft is located at the second position moving at the velocity at the subsequent time, and based on a confirmation that it is possible, providing an indication that the second signal is authentic.