Aircraft terrain warning systems and methods

• US 7,570,177 B2
• Filed: 06/19/2006
• Issued: 08/04/2009
• Est. Priority Date: 12/20/2002
• Status: Active Grant

• Current Assignee: Aviation Communication and Surveillance Systems LLC (L3Harris Technologies, Inc.)
• Original Assignee: Aviation Communication and Surveillance Systems LLC (L3Harris Technologies, Inc.)
• Inventors: Reynolds, Zachary, Stone, Cyro, Rowlan, Stacey, Ridenour, Richard
• Primary Examiner(s): Swarthout; Brent
• Application Number:
  US11/471,401
• Publication Number:
  US 20060290531A1
• Time in Patent Office: 1,142 Days
• Field of Search: 340/961, 340/963, 340/970, 340/968, 701/9, 701/4, 701/14, 701/301, 342/65
• US Class Current: 340/961
• CPC Class Codes: B64D 45/04 Landing aids; Safety measures to prevent collision with earth's surface
• CPC Class Codes: G08G 5/0086 for monitoring terrain radar or analogous systems specially adapted for terrain avoidance G01S13/935
• CPC Class Codes: G08G 5/045 Navigation or guidance aids, e.g. determination of anti-collision manoeuvers radar or analogous systems specially adapted for anti-collision between aircraft G01S13/933

Abstract

Methods and systems are disclosed for preventing aircraft collisions with forward looking terrain avoidance (FLTA) functionality based on a terrain avoidance profile used to evaluate potential terrain threats based on the projected flight path of an aircraft in flight, and a clear terrain profile to determine whether the terrain threat has been cleared. If the terrain avoidance profile conflicts with terrain, a collision threat may exist whereby the pilot is notified and a terrain avoidance maneuver is executed. During the terrain avoidance maneuver the clear terrain profile extends in a direction substantially parallel with the horizon at or near the present altitude of the aircraft to check whether it is safe to return to the previous flight path angle or otherwise end the terrain-avoiding maneuver. When the clear terrain profile no longer conflicts with the terrain threat, a terrain clear indicator is then issued to the pilot.

Claims

1. A method for preventing controlled flight into terrain, the method comprising:

providing a first indicator to a pilot of an aircraft that a threat of potential collision with terrain exists;

providing a second indicator to the pilot of the aircraft that the threat no longer exists;

comparing with a processor, a terrain avoidance profile with terrain information to determine whether the threat exists, the terrain avoidance profile including a climb gradient profile portion based on a recently-demonstrated flight performance characteristic of the aircraft; and

comparing with the processor, a clear terrain profile with the terrain information to determine whether the threat no longer exists.

2. The method of claim 1 wherein the first indicator comprises an aural alert instructing the pilot to maneuver to avoid the threat and wherein the second indicator comprises an aural alert identifying that the threat no longer exists.

3. The method of claim 1 wherein the clear terrain profile includes an altitude safety margin.

4. The method of claim 2 wherein the terrain avoidance profile comprises a projected flight path portion.

5. The method of claim 4 wherein the climb gradient profile portion is based on at least one performance characteristic of the aircraft.

6. The method of claim 2 wherein the first and second indicators further comprise respective visual alerts on one or more displays.

7. The method of claim 5 wherein the at least one performance characteristic comprises one or more published performance characteristics of the aircraft.

8. The method of claim 5 wherein the at least one performance characteristic comprises at least one dynamic performance characteristic.

9. The method of claim 4 wherein the projected flight path portion includes a pilot reaction time segment.

10. The method of claim 1 wherein providing the first and second indicators comprises comparing one or more terrain profiles with terrain position and altitude information.

11. The method of claim 10 wherein the one or more terrain profiles comprises a terrain avoidance profile and a terrain clearance profile.

19. The method of claim 1 wherein the clear terrain profile includes a terrain check segment that is independent of a climb angle for the aircraft and a flight path angle for the aircraft.

20. The method of claim 1 wherein the climb gradient profile is further based on a known deficiency in the aircraft'"'"'s performance.

12. An apparatus for monitoring potential aircraft collision threats with terrain, the apparatus comprising:

a memory storing machine readable code; and

a processor when processing the stored machine readable code in said memory is operative to;

(a) compare a terrain avoidance profile with terrain information to identify a potential collision threat, the terrain avoidance profile including a climb gradient profile portion based on a recently-demonstrated flight performance characteristic of the aircraft;

(b) generate a terrain warning signal when the potential collision threat is identified;

(c) compare a forward projection of current aircraft altitude with the terrain information to identify if a terrain threat has been avoided; and

(d) generate a terrain clear signal when the terrain threat has been avoided.

13. The apparatus of claim 12 wherein the processing device comprises a ground collision avoidance system processor mounted in the aircraft.

14. The apparatus of claim 13 wherein the processing device further processes traffic collision avoidance system information for preventing collisions with surrounding aircraft.

21. The apparatus of claim 12 wherein the climb gradient profile is further based on a known deficiency in the aircraft'"'"'s performance.

15. A system for avoiding aircraft collisions with terrain, the system comprising:

storage means for storing information relating to terrain features;

processing means for;

(a) comparing a terrain avoidance profile with the information stored in said storage means, wherein the terrain avoidance profile includes a climb gradient profile portion based on a recently-demonstrated flight performance characteristic of the aircraft;

(b) generating an alert signal based upon said comparison if said comparison indicates a potential threat;

(c) comparing a clear terrain profile with said information when said alert signal has been generated; and

(d) generating a terrain clear signal when said terrain clearance profile does not conflict with said information.

16. The system of claim 15 further comprising output means for converting the alert signal and the terrain clear signal to at least one of an audible and visual form.

17. The system of claim 15 further comprising input means for providing inputs to the processor means regarding at least one of aircraft flight data and aircraft performance information.

18. The system of claim 15 wherein the processing means further serve for comparing surrounding aircraft traffic data to flight data to determine potential collisions with surrounding aircraft traffic.

22. The system of claim 15 wherein the climb gradient profile is further based on a known deficiency in the aircraft'"'"'s performance.