ONBOARD SYSTEM FOR THE PREVENTION OF COLLISIONS OF AN AIRCRAFT WITH THE GROUND WITH END-OF-CONFLICT INDICATION

• US 20100274486A1
• Filed: 03/08/2007
• Published: 10/28/2010
• Est. Priority Date: 03/08/2006
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: LORIDO, Didier, SALMON, Philippe, MARTY, Nicolas
• Granted Patent: US 7,881,867 B2
• Time in Patent Office: Days
• US Class Current: 701/301
• CPC Class Codes: G08G 5/0086 for monitoring terrain radar or analogous systems specially adapted for terrain avoidance G01S13/935

Abstract

The TAWS system, in addition to an FTLA function for detecting the risk of collision with the terrain, has an end-of-conflict announcement function COT which is activated after the cessation of a warning or alarm concerning the risk of collision with the ground originating from the FTLA function. This COT function, when activated, checks that the aircraft (A) is observing minimum vertical and lateral safe distances, and estimates the lower vertical speed margin with which a new ground collision risk warning will not be retriggered. After confirming the observance of the minimum safe distances, the COT function has an end-of-conflict message (“Clear of terrain”) sent with a lower vertical speed margin indication.

Claims

1. An onboard system for the prevention of collisions of an aircraft with the ground comprising:

a detector of risk of collision with the terrain by comparing a risk of collision of the aircraft with the terrain within a predetermined prediction period, with the penetration of a topographic representation of the terrain being flown over generated from cartographic data stored in a database accessible from the aircraft, into at least one maneuver protection volume linked to the aircraft, located relative to the terrain being flown over by means of a locating device that is on board and oriented in the direction of movement of the aircraft, and a message generator generating warnings on request from the collision risk detector;

means of checking that the aircraft is observing minimum safe distances from the terrain being flown over,

means of determining a lower vertical speed margin implementing an additional vertical speed margin protection volume, linked to the aircraft, with a lower longitudinal profile beginning, on the aircraft side, with a path extrapolated from the current path of the aircraft tilted downward, until the topographic representation of the terrain being flown over penetrates into the additional vertical speed margin protection volume, and comparing the angular tilt amplitude found with the lower vertical speed margin, and

means of triggering the message generator requiring the message generator to send an end of conflict with the ground message, with lower vertical speed margin indication, after an end of triggering of the ground collision risk detector and confirmation by the checking means that the aircraft is observing minimum safe distances.

2. The system according to claim 1, wherein the minimum safe distances in the vertical plane considered by the checking means depend on the flight phase of the aircraft, defined as a function of its flight level, its speed and its distance to an airport.

3. The system according to claim 1, wherein the checking means take account of the current position of the aircraft and its positions in a near future deduced from a path extrapolation created from the flight parameters.

4. The system according to claim 3, wherein the checking means take account of the current position of the aircraft and its positions in the next twenty or so seconds.

5. The system according to claim 1, wherein the checking means comprise a minimum vertical margin detector sensitive to the penetration of the topographic representation of the terrain being flown over into an additional vertical margin protection volume linked to the aircraft and having a lower surface profile modeling a potential leveling-off path initiated from the current position of the aircraft assumed to be engaged in a steep descent close to the limit allowed in normal operating conditions.

6. The system according to claim 5, wherein the additional vertical margin protection volume has a modeling lower surface profile on a leveling-off path over a period of the order of two minutes.

7. The system according to claim 1, wherein the minimum safe distances in the horizontal plane, considered by the checking means in the horizontal plane, take account of the lateral distances needed for the aircraft to describe a holding pattern.

8. The system according to claim 1, wherein the additional vertical speed margin protection volume has, initially, the same configuration as a maneuver protection volume.

9. The system according to claim 1, wherein the additional vertical speed margin protection volume comprises a maneuver protection volume progressively tilted overall downward.

10. The system according to claim 1, wherein the additional vertical speed margin protection volume has its lower longitudinal profile tilted downward, in successive steps and in a dichotomic manner, until it is penetrated by the topographic representation of the terrain being flown over.