Terrain awareness system

• US 6,606,034 B1
• Filed: 07/31/1995
• Issued: 08/12/2003
• Est. Priority Date: 07/31/1995
• Status: Expired due to Term

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Johnson, Steven C., Conner, Kevin J., Muller, Hans R.
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US08/509,660
• Time in Patent Office: 2,934 Days
• Field of Search: 340/963, 340/970, 340/967, 340/976, 342/65, 364/424.06, 364/430, 701/9, 701/301, 701/14, 701/4, 731/78.R, 731/78.T
• US Class Current: 340/970
• CPC Class Codes: G01S 13/953 mounted on aircraft
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 7/12 Plan-position indicators, i.e. P.P.I.
• CPC Class Codes: G01S 7/22 Producing cursor lines and indicia by electronic means
• CPC Class Codes: G08G 5/0086 for monitoring terrain radar or analogous systems specially adapted for terrain avoidance G01S13/935
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

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. A warning system for providing an indication to the pilot of an aircraft of the proximity of terrain to the aircraft, the warning system comprising:

means for receiving signals representative of the position of the aircraft;

means for storing data representative of terrain elevations, obstacle elevations and one or more predetermined reference points for one or more predetermined geographical areas;

means for receiving signals representative of a flight path angle of the aircraft;

means for determining the distance of the aircraft relative to one of said one or more predetermined reference points;

first comparing means for comparing the flight path angle of the aircraft with a first fixed predetermined datum having a first predetermined angle relative to a horizontal axis; and

first generating means for generating first advisory boundary signals defining a plurality of first advisory boundaries as a predetermined function of said first predetermined angle of said first fixed reference predetermined datum and said distance to said predetermined reference point for a first predetermined distance in front of said aircraft when said flight path angle is less than said first predetermined angle of said first predetermined fixed datum and generating said first advisory boundary signals as a predetermined function of said flight path angle and said distance to said predetermined reference point for said first predetermined distance in front of the aircraft when said flight path angle is not less than said first predetermined angle of said first predetermined fixed datum.

2. A warning system as recited in claim 1, further including means for determining when said aircraft is descending and wherein said first generating means includes means for generating one of said plurality of first advisory boundaries as a predetermined function of a first variable reference datum for said first predetermined distance in front of said aircraft, said first variable reference datum being a predetermined function of said flight path angle.

3. A warning system as recited in claim 2, further including means for receiving signals representative of the ground speed of the aircraft, and wherein said first predetermined distance is a predetermined function of the ground speed of the aircraft.

4. A warning system as recited in claim 1, wherein said first generating means includes means for generating first warning boundary signals defining a plurality of first warning boundaries as a predetermined function of said first predetermined angle of said first fixed reference datum and the distance to said predetermined reference point for a second predetermined distance in front of the aircraft when said flight path angle is less than said first predetermined angle of said first predetermined reference datum and generating said first warning boundary signals as a predetermined function of said flight path angle and the distance to said predetermined reference point for said second predetermined distance in front of the aircraft when said flight path angle is not less than said first predetermined angle of said predetermined fixed datum.

5. A warning system as recited in claim 4, further including means for determining when said aircraft is descending and wherein said first generating means includes means for generating a first warning boundary as a predetermined function of a second variable reference datum for said second predetermined distance in front of said aircraft, said second variable reference datum being a predetermined function of said flight path angle.

6. A warning system as recited in claim 4, further including second comparing means for comparing the flight path angle with a second predetermined fixed datum at a second predetermined angle, means for receiving a signal representative of the vertical speed of the aircraft, and second generating means for generating second advisory boundary signals defining a plurality of second advisory boundaries as a predetermined function of said second predetermined fixed datum, the distance to said predetermined reference point and the vertical speed of the aircraft for a first predetermined distance in front of the aircraft when said flight path angle is less than said second predetermined angle of said second predetermined fixed datum and generating said second advisory boundary signals as a predetermined function of said flight path angle, the distance to said predetermined reference point and the vertical speed of the aircraft for said first predetermined distance when said flight path angle is greater than said second predetermined angle of said second predetermined fixed datum.

7. A warning system as recited in claim 6, wherein said second generating means includes means for generating second warning boundary signals defining a plurality of second warning boundaries as a predetermined function of said second predetermined fixed datum, the distance to said second predetermined reference point and the vertical speed of the aircraft for a second predetermined distance when said flight path angle is less than said second predetermined angle of said second predetermined fixed datum and generating said second warning boundary signals as a predetermined function of said flight path angle, the distance to said predetermined reference point and the vertical speed of the aircraft for said second predetermined distance when said flight path angle is greater than said second predetermined angle of said second predetermined fixed datum.

8. A warning system as recited in claim 4, further including means for inhibiting said first generating means as a predetermined function of one or more predetermined altitudes.

9. A warning system as recited in claim 8, wherein at least one of said one or more predetermined altitudes is variable.

10. A warning system for providing an indication to the pilot of an aircraft of the proximity of terrain to the aircraft, the warning system comprising:

means for receiving signals representative of the position of the aircraft;

means for storing terrain data representative of the terrain elevations, obstacle elevations and one or more predetermined reference points for one or more predetermined geographical areas;

means for receiving signals representative of the altitude of the aircraft;

means for determining the current altitude of the aircraft;

first generating means for generating a first advisory envelope, said first advisory envelope having a plurality of segments, one of said segments extending downwardly from the current position and altitude of said aircraft for a predetermined distance which varies as a predetermined function of the distance of the aircraft to a predetermined reference point defining a first segment of said first advisory envelope.

11. A warning system as recited in claim 10, further including means for receiving signals representative of the flight path angle of the aircraft and wherein said first generating means includes means for generating a second segment of said first advisory envelope extending from said first segment of said first advisory envelope along a first predetermined fixed datum at a first predetermined angle for a first predetermined distance in front of said aircraft, when said flight path angle is less than said first predetermined angle, wherein said second segment of said first advisory envelope extends from said first segment of said first advisory envelope at the flight path angle for said first predetermined distance when said flight path angle is greater than said first predetermined angle.

12. A warning system as recited in claim 11, further including means for receiving signals representative of the ground speed of the aircraft and wherein said first predetermined distance is a predetermined function of said ground speed of said aircraft.

13. A warning system as recited in claim 12, further including means for expanding said first advisory envelope as a predetermined function of a first predetermined variable datum.

14. A warning system as recited in claim 13, further including means for determining when said aircraft is descending and expanding said first advisory envelope as a predetermined function of said first predetermined variable datum, wherein said first predetermined variable datum is a predetermined function of said flight path angle.

15. A warning system as recited in claim 10, further including means for generating a first warning envelope for a second predetermined distance in front of said aircraft, said first warning envelope having a plurality of segments, one of said segments extending downwardly from the current position and altitude of the aircraft for a distance which varies as a predetermined function of the distance of the aircraft to a predetermined reference point defining a first segment of said first warning envelope.

16. A warning system as recited in claim 15, further including means for receiving signals representative of the flight path angle of the aircraft and wherein said first generating means includes means for generating a second segment of said first warning envelope extending from said first segment of said first warning envelope along a first predetermined fixed datum at a first predetermined angle for a second predetermined distance in front of the aircraft, when said flight path angle is less than said first predetermined angle, wherein said second segment of said first warning envelope extends from said first segment of said first warning envelope at the flight path angle for said second predetermined distance when said flight path angle is greater than said first predetermined angle.

17. A warning system as recited in claim 16, further including means for determining when said aircraft is descending and expanding said first warning envelope as a predetermined function of said second predetermined variable datum, said second predetermined variable datum being a predetermined function of said flight path angle.

18. A warning system for an aircraft comprising:

means for receiving signals representative of the instantaneous flight path angle of the aircraft;

means for receiving signals representative of the position of the aircraft;

means for receiving signals representative of the altitude of the aircraft;

means for storing data representative of actual terrain elevation information;

means for generating a first warning signal of a hazardous flight condition resulting from location of a subset of said predetermined terrain information at a predetermined distance in front of the aircraft, said first warning signal generated as a function of both the position of the aircraft relative to said subset of said predetermined terrain information and the flight path angle of the aircraft;

wherein said first warning signal defines a plurality of boundaries relative to the current position and altitude of the aircraft;

means for modifying said boundaries under predetermined conditions;

said modifying means including means for modifying said boundaries as a function of the flight path angle of the aircraft; and

means for inhibiting said modifying means when said flight path angle is greater than a predetermined angle.

19. A warning system for an aircraft comprising:

means for receiving signals representative of the flight path angle of the aircraft;

means for receiving signals representative of the position of the aircraft;

means for receiving signals representative of the altitude of the aircraft;

means for storing data representative of actual terrain elevation information;

means for generating a first warning signal of a hazardous flight condition resulting from location of a subset of said predetermined terrain information at a predetermined distance in front of the aircraft, said first warning signal generated as a function of both the position of the aircraft relative to said subset of said predetermined terrain information and the flight path angle of the aircraft;

wherein said first warning signal defines a plurality of boundaries relative to the current position and altitude of the aircraft;

means for modifying said boundaries under predetermined conditions; and

wherein said modifying means further includes a means for determining a relationship between the flight path angle and a first datum and for modifying said first datum as a function of the flight path angle of the aircraft.