Method and apparatus for terrain awareness

• US 6,219,592 B1
• Filed: 05/08/1998
• Issued: 04/17/2001
• Est. Priority Date: 07/31/1995
• Status: Expired due to Term

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Johnson, Steven C., Conner, Kevin J., Muller, Hans R.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): PIPALA, EDWARD J
• Application Number:
  US09/074,953
• Time in Patent Office: 1,075 Days
• Field of Search: 701/3, 701/4, 701/8, 701/9, 701/120, 701/300, 701/301, 701/302, 701/207, 701/208, 701/209, 701/213, 340/945, 340/963, 340/964, 340/970, 340/971, 340/977, 731/78.R, 731/78.T, 244/180, 244/181
• US Class Current: 701/9
• CPC Class Codes: G01C 5/005 altimeters for aircraft G01C5/02, G01C5/06 take precedence
• CPC Class Codes: G05D 1/0676 specially adapted for landing

Abstract

A terrain awareness system (TAS) provides LOOK-AHEAD/LOOK-DOWN as well as LOOK-UP terrain advisory and warning indications to the pilot of an aircraft of a hazardous flight condition. The TAS includes an airport data base as well as a terrain data base that is structured to provide various resolutions depending on the topography of the particular geographic area of interest. Navigational data from a satellite-based navigational system, such as a global positioning system (GPS), is used to provide a LOOK-AHEAD/LOOK-DOWN and LOOK-UP terrain advisory and terrain warning indications based upon the current position and projected flight path of the aircraft. Since the terrain advisory and the warning signals are a function of the flight path of the aircraft, nuisance warnings are minimized.

Claims

1. An apparatus for alerting a pilot of an aircraft of proximity to terrain, the apparatus comprising,

an input for receiving signals representative of a position of the aircraft, a flight path angle of the aircraft and a speed of the aircraft, and coupled to a data base of stored terrain information;

an output;

a signal processing device, coupled to said input, and coupled to said output, for;

(a) defining a look ahead distance as a function of the speed of die aircraft;

(b) defining a first alert envelope, indicative of a first severity of terrain threat, wherein boundaries of said first alert envelope in a first plane are determined as a first function of the fight path angle, said look ahead distance, and a terrain floor boundary;

(c) defining a second alert envelope, indicative of a second severity of terrain threat, wherein boundaries of said second alert envelope in a first plane are determined as a second function of the flight path angle, said look ahead distance and said terrain floor boundary;

(d) defining, in a second plane, lateral boundaries of said first and said second alert envelopes relative to a ground track of the aircraft; and

(e) outputting an alert signal when a subset of the stored terrain information is located within the boundaries of at least one of said first and said second alert envelopes.

2. The apparatus of claim 1 wherein at least one of said first and second alert envelopes is further bounded by a cutoff envelope.

3. The apparatus of claim 1 wherein said signals representative of the position of an aircraft include a first signal received from a satellite navigation system indicative of an aircraft altitude and a second signal representative of the aircraft altitude received from a source other than the satellite navigation system, and wherein said signal processing device further comprises a means for determining a compound altitude signal.

4. The apparatus of claim 1 wherein the boundaries of at least one of said first and second alert envelopes is further determined as a function of a configurable datum.

5. The apparatus of claim 1 wherein at least one of said first and second alert envelopes further comprise a subset of alert envelopes representing various severities of hazard to the aircraft.

6. The apparatus of claim 1 wherein said signal processing device comprises a microprocessor.

7. The apparatus of claim 1 wherein said signal processing device comprises a means for outputting said alert signal as a video control signal, wherein said video control signal is useful for controlling representation of terrain on a video display in various colours according to a degree of terrain threat.

8. An apparatus for alerting a pilot of an aircraft of proximity to terrain, the apparatus comprising:

an input for receiving signals representative of a position of the aircraft, a flight path angle of the aircraft and a speed of the aircraft, and coupled to a data base of stored terrain information;

an output;

a signal processing device, coupled to said input, and coupled to said output, for;

(a) defining a look ahead distance as a function of the speed of the aircraft,

(b) defining a first alert envelope, indicative of a first severity of terrain threat, wherein boundaries of said first alert envelop in a first plane are determined as a first function of the flight path angle, said look ahead distance, and a terrain floor boundary;

(c) defining a second alert envelope, indicative of a second severity of terrain threat, wherein boundaries of said second alert envelope are in a first plane are determined as a second function of the flight path angle, said look ahead distance and said terrain floor boundary;

(d) defining in a second plane, lateral boundaries of said first and said second alert envelopes by defining a first point and a second point port and starboard of the aircraft respectively and projecting a line out from each of said first and said second points at a configurable angle;

(e) outputting an alert signal when a subset of the stored terrain information is located within the boundaries of at least one of said first and said second alert envelopes.

9. The apparatus of claim 8 wherein at least one of said first and second alert envelopes is further bounded by a cutoff envelope.

10. The apparatus of claim 8 wherein said signals representative of the position of an aircraft include a first signal received from a satellite navigation system indicative of an aircraft altitude and a second signal representative of the aircraft altitude received from a source other than the satellite navigation system, and wherein said signal processing device further comprises a means for determining a compound altitude signal.

11. The apparatus of claim 8 wherein the boundaries of at least one of said first and second alert envelopes is further determined as a function of a configurable datum.

12. The apparatus of claim 8 wherein at least one of said first and second alert envelopes further comprises a subset of alert envelopes representing various severaties of hazard to the aircraft.

13. The apparatus of claim 8 wherein said signal processing device comprises a microprocessor.

14. The apparatus of claim 8 wherein said signal processing device comprises a means for outputting said alert signal as a video control signal, wherein said video control signal is useful for controlling representation of terrain on a video display in various colors according to a degree of terrain threat.

15. A method for alerting a pilot of an aircraft of proximity to terrain, comprising the steps;

receiving signals representative of a position of the aircraft, a flight path angle of the aircraft and a speed of the aircraft, and stored terrain information;

defining a look ahead distance as a function of the speed of the aircraft;

defining a first alert envelopes indicative of a first severity of terrain threat, wherein boundaries of said first alert envelope in a first plane are determined as a first function of the flight path angle, said look ahead distance, and a terrain floor boundary;

defining a second alert envelope, indicative of a second severity of terrain threat, wherein boundaries of said second alert envelope in a first plane are determined as a second function of the flight path angle, said look ahead distance and said terrain floor boundary;

defining, in a second plane, lateral boundaries of said first and said second alert envelopes relative to a ground track of the aircraft; and

outputting an alert signal when a subset of the stored terrain information is located within the boundaries of at least one of said first and said second alert envelopes.

16. A method for alerting a pilot of an aircraft of proximity to terrain comprising the steps of:

receiving signals representative of a position of the aircraft a flight path angle of the aircraft and a speed of the aircraft, and stored terrain information;

defining a look ahead distance as a function of the speed of the aircraft;

defining a first alert envelope indicative of a first severity of terrain threat, wherein boundaries of said first alert envelope in a first plane are determined as a first function of the flight path angle, said look ahead distance, and a terrain floor boundary;

defining a second alert envelope, indicative of a second severity of terrain threat, wherein boundaries of said second alert envelope are in a first plane are determined as a second function of the flight path angle, said look ahead distance and said terrain floor boundary;

defining, in a second plane, lateral boundaries of said first and said second alert envelopes by defining a first point and a second point port and starboard of the aircraft respectively and projecting a line out from each of said first and said second points at a configurable angle; and

outputting an alert signal when a subset of the stored terrain information is located within the boundaries of at least one of said first and said second alert envelopes.