Laser beacon and optical detector system for aircraft collision hazard

Abstract

A laser beacon mounted on a first aircraft emits a beam which is sensed by an optical detector on a second aircraft in such a manner that a collision proximity warning device is triggered and/or collision avoidance maneuvers are initiated. The system is intended to prevent aircraft collisions which occur under visual flight regulation (VFR) conditions and which constitute in excess of 90% of civil aircraft mid-air accidents. In the preferred embodiment a horizontally collimated, vertically diverging laser beam is made to rotate 360.degree. in polarization while simultaneously rotating 360.degree. in azimuth with respect to the first aircraft. The optical detector mounted on the second aircraft preferably comprises a pair of horizontally offset light collectors which include narrow spectral width filters respectively and various other components which collectively determine the bearing, range and relative heading of the first aircraft. The information is stored so that subsequent signals arising from the first aircraft may be compared to determine trajectories and range rates. Collision warning and/or collision avoidance actions may then be started if the information indicates a high probability of collision. Alternative embodiments of the optical detector apparatus can be constructed with varying complexities to meet the needs of aircraft operating at different speeds or in different flight environments.