Aircraft terrain information system

• US 20010056316A1
• Filed: 06/25/2001
• Published: 12/27/2001
• Est. Priority Date: 07/31/1995
• Status: Active Grant

• Current Assignee: Howard Glover, Steven C. Johnson
• Original Assignee: Howard Glover, Steven C. Johnson
• Inventors: Glover, Howard, Johnson, Steven C.
• Granted Patent: US 6,691,004 B2
• Time in Patent Office: Days
• US Class Current: 701/14
• CPC Class Codes: G01C 23/00 Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed or acceleration
• 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
• 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

An aircraft terrain warning generator is provided having a terrain and obstacle warning envelope having a lower boundary formed according to the lesser of the current aircraft flight path angle and the obtainable climb gradient.

Claims

1. A method for determining the current weight of an aircraft for determining a currently obtainable climb gradient, the method comprising:

determining the lift coefficient of the aircraft;

determining the steady-state flight of the aircraft;

determining current dynamic pressure;

calculating current aircraft weight during said steady-state flight of the aircraft as a function of said dynamic pressure, said lift coefficient, and the aircraft wing surface area.

2. The method recited in

claim 1

, wherein said determining said lift coefficient further comprises receiving signals representative of aircraft angle of attack and flap angle and calculating said lift coefficient as a function of said signals.

3. The method recited in

claim 1

, wherein said determining said steady-state flight of the aircraft further comprises receiving signals representative of current airspeed, vertical speed, roll angle, and gear position, and monitoring said signals during a predetermined minimum time period.

4. The method recited in

claim 1

, wherein said determining current dynamic pressure further comprises receiving signals representative of airspeed, pressure altitude and air temperature and calculating said current dynamic pressure as a function of said signals.

5. A method for determining a currently obtainable climb gradient of an aircraft, the method comprising:

determining an estimated aircraft weight as a function of phase of flight;

determining the current aircraft weight as a function of the current dynamic pressure, the unaccelerated lift of the aircraft, and the wing surface area of the aircraft during steady-state flight;

updating said estimated aircraft weight as a function of said current aircraft weight;

determining the current lift and drag coefficients of the aircraft;

determining currently available aircraft thrust; and

estimating a currently obtainable maximum climb gradient as a function of said thrust, current weight, current lift and drag coefficients.

6. The method recited in

claim 5

, wherein said current lift and drag coefficients are defined by functions of angle of attack and flap configuration.

7. The method recited in

claim 5

, wherein said determining currently available aircraft thrust further comprises determining the status of one or more engine out indicators.

8. The method recited in

claim 7

, wherein said determining currently available aircraft thrust further comprises de-rating a maximum take off thrust as a function of current altitude.

9. The method recited in

claim 8

, wherein said determining currently available aircraft thrust further comprises de-rating a maximum take off thrust as a function of a current wind correction factor.