Aircraft terrain warning systems and methods

• US 20060290531A1
• Filed: 06/19/2006
• Published: 12/28/2006
• 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, Ridenour, Richard, Stone, Cyro, Rowlan, Stacey
• Granted Patent: US 7,570,177 B2
• Time in Patent Office: Days
• 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 a terrain avoidance profile with terrain information to determine whether the threat exists; and

comparing 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 and a climb gradient profile 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 of the aircraft.

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.

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, compare an altitude and a bearing of an aircraft with terrain information to identify a potential collision threat, generate a terrain warning signal when the potential collision threat is identified, compare a forward projection of current aircraft altitude with the terrain information to identify if a terrain threat has been avoided; and

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.

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

storage means for storing information relating to terrain features;

processing means for comparing a terrain avoidance profile with the information stored in said storage means, for generating an alert signal based upon said comparison if said comparison indicates a potential threat, for comparing a clear terrain profile with said information when said alert signal has been generated, and for 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.

19. A method for warning a pilot of situational threats during flying, the method comprising:

determining that a terrain threat exists with reference to criteria of a first sensor; and

determining that the terrain threat has been averted with reference to criteria of a second sensor.

20. The method of claim 19 wherein after determining that the terrain threat exists, the method further comprises, continuously advising the pilot that corrective action should be maintained at least until it is determined that the terrain threat has been averted.

21. The method of claim 20 wherein after determining that the terrain threat has been averted the method comprises advising the pilot that the threat has been averted.

22. The method of claim 19 wherein upon determining that the threat exists, the method further comprises indicating to the pilot that the second sensor is in use.

23. The method of claim 19 wherein the first and second sensors respectively comprise a terrain avoidance profile and a clear terrain profile.