Patent ID: 6546338
Filing Date: 2003-04-08
Classification: G01S,G08G

Abstract:
Method for preparation of an avoidance path in a horizontal plane, for a first aircraft following an initial route, to resolve a conflict of traffic with a second aircraft following a second route that may be identical to the first route, based on knowledge (a) of a minimum safety distance S to be maintained between the first and second aircraft, (b) of current positions X1 and X2 of the first and second aircraft, and (c) of horizontal speed vectors {right arrow over (Vâ€‰)}1 and {right arrow over (Vâ€‰)}2 of the first and second aircraft, said method comprising:determining a horizontal speed vector {right arrow over (Vâ€‰)}rel of the second aircraft relative to the first aircraft; determining, in the horizontal plane, a circle of protection around the first aircraft with the minimum safety distance as its radius; testing an intersection of a straight line bearing the horizontal speed vector {right arrow over (Vâ€‰)}hd rel of the second aircraft with respect to the first aircraft, with the circle of protection of the first aircraft; further comprising, in an event the intersection of the circle of protection of the first aircraft by the horizontal speed vector {right arrow over (Vâ€‰)}rel of the second aircraft relative to the first aircraft, implying a risk of collision, tests affirmative; determining an angle {right arrow over (&agr;â€‰)}b-{right arrow over (&agr;â€‰)}c at which the second aircraft perceives the circle of protection of the first aircraft; determining a start-of-avoidance-maneuver point located on the initial route of the first aircraft and shifted downline from the current position X1 of the first aircraft; determining at least one value of heading angle {right arrow over (&THgr;â€‰)}1b and/or {right arrow over (&THgr;â€‰)}1c to be followed by the first aircraft, without changing a horizontal speed modulus, to bring the horizontal speed vector {right arrow over (Vâ€‰)}rel of the second aircraft relative to the first aircraft at most on one of sides {right arrow over (Xâ€‰)}2b, {right arrow over (Xâ€‰)}2c of the angle at which the second aircraft perceives the circle of protection of the first aircraft; and determining at least one collision-risk avoidance path for the first aircraft comprising a first evasive path constituted by a rectilinear segment having the start-of-avoidance-maneuver point as its point of origin, one of new values of the obtained heading angle {right arrow over (&THgr;â€‰)}1b or {right arrow over (&THgr;â€‰)}1c as its heading and having, as its end, a rotating point chosen beyond a point where the separation distance between the first and second aircraft passes through a minimum value equal to a minimum safety distance, and, beyond the rotating point, a second homing path to the initial route.