TCAS II pitch guidance control law and display symbol
First Claim
1. Apparatus for creating a Traffic alert and Collision Avoidance System (TCAS) Resolution Advisory (RA) pitch guidance symbol on an electronic attitude display of an airplane in response to a collision avoidance vertical speed command created by a TCAS computer when an intruder enters the airspace protected by the TCAS computer, said apparatus comprising:
- (a) pitch guidance control means for;
(i) receiving data representing the collision avoidance vertical air speed command created by a TCAS computer when an intruder enters the airspace protected by the TCAS computer;
(ii) receiving data from the airplane representing the vertical air speed of the airplane;
(iii) receiving a sensitivity factor whose value depends on the true air speed of the airplane; and
(iv) producing a Resolution Advisory (RA) command; and
(b) an electronic attitude display means that includes an airplane symbol and a pitch axis scale for receiving said RA command and creating a Resolution Advisory (RA) pitch guidance symbol positioned on said display in association with said pitch axis scale and said airplane symbol.
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Accused Products
Abstract
An airplane pitch guidance control law and display symbol for a Traffic alert and Collision Avoidance System (TCAS) is disclosed. The control law converts a TCAS computer-generated vertical air speed command into a pitch guidance command. The pitch guidance command controls the location of a symbol (51) on the pitch axis of an electronic attitude display (21) that guides a pilot toward a pitch attitude that will result in a vertical speed that eliminates a collision threat. The preferred symbol is a pitch axis leg (53) and a pair of outwardly diverging legs (55a, 55b). The pitch axis leg (53) defines the minimum climb or descent attitude required to achieve a safe climb or descent angle. The pitch axis leg (53) and the diverging legs (55a, 55b) combine to define a climb or descent attitude range to avoid. The distance between the pitch axis leg 53 and the boresight 39 of the airplane symbol of the display is controlled by a RACMD signal produced by: subtractively combining the vertical speed command (VSTCAS ) produced by a TCAS II computer and the vertical speed of the airplane (VSIND); multiplying the result by a sensitivity factor K whose value is related to the true air speed of the airplane and 57.3 to approximate the arc tangent of the quotient; and subtracting a factor that compensates for the fact that flight path angle changes lag pitch attitude changes.
66 Citations
30 Claims
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1. Apparatus for creating a Traffic alert and Collision Avoidance System (TCAS) Resolution Advisory (RA) pitch guidance symbol on an electronic attitude display of an airplane in response to a collision avoidance vertical speed command created by a TCAS computer when an intruder enters the airspace protected by the TCAS computer, said apparatus comprising:
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(a) pitch guidance control means for; (i) receiving data representing the collision avoidance vertical air speed command created by a TCAS computer when an intruder enters the airspace protected by the TCAS computer; (ii) receiving data from the airplane representing the vertical air speed of the airplane; (iii) receiving a sensitivity factor whose value depends on the true air speed of the airplane; and (iv) producing a Resolution Advisory (RA) command; and (b) an electronic attitude display means that includes an airplane symbol and a pitch axis scale for receiving said RA command and creating a Resolution Advisory (RA) pitch guidance symbol positioned on said display in association with said pitch axis scale and said airplane symbol. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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- 22. In an electronic attitude display of an airplane that includes an airplane symbol and a pitch axis scale, the improvement comprising a Resolution Advisory (RA) pitch guidance symbol positioned on said display in association with said pitch axis scale and said airplane symbol, wherein said RA pitch guidance symbol delineates a portion of said pitch axis scale to be avoided by said airplane symbol in order to eliminate a threat of a collision with an intruder in the surrounding airspace.
Specification