Methods, apparatus and computer program products for determining a corrected distance between an aircraft and a selected runway

• US 6,477,449 B1
• Filed: 02/01/2000
• Issued: 11/05/2002
• Est. Priority Date: 02/01/1999
• Status: Expired due to Term

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Johnson, Steven C., Conner, Kevin J
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Pipala, Edward J.
• Application Number:
  US09/495,630
• Time in Patent Office: 1,008 Days
• Field of Search: 701/4, 701/16, 701/17, 701/18, 701/205, 701/300, 701/302, 340/945, 340/963, 340/972, 340/976, 342/32, 342/33, 244/183, 244/186
• US Class Current: 701/4
• CPC Class Codes: G08G 5/025 Navigation or guidance aids radar or analogous systems specially adapted for landing purposes G01S13/913

Abstract

The present invention provides several apparatus, methods, and computer program products for determining a corrected distance between an aircraft and selected runway, such that the corrected distance may be used for ground proximity warning calculations. Specifically, the present invention includes a processor that receives data related to the coordinates of the aircraft and a selected runway. Based on these coordinate values, the processor determines a coordinate distance between the aircraft and selected runway. The processor also compares the altitude of the aircraft to a predetermined glideslope constructed about the runway. Specifically, the processor calculates a distance value that corresponds to the altitude of the aircraft above the runway along the predetermined glideslope. The processor compares the coordinate distance and the calculated distance values and selects either the coordinate distance or the calculated distance value as the corrected distance between the aircraft and the selected runway. For instance, in one embodiment, the processor compares the coordinate and calculated distance values and selects the larger of the values as the corrected distance between the aircraft and the selected runway. The present invention also provides a processor for determining a look ahead distance value for ground proximity warning calculations. The processor of this embodiment, initially determines differing look ahead distance values based on the corrected distance to the runway, ground speed of the aircraft, and the actual roll angle of the aircraft. The processor compares the three look ahead distance values and selects the smallest of the look ahead distance values for use in the ground proximity warning system.

Claims

1. An apparatus for determining a corrected distance between an aircraft and a selected runway based on an altitude and distance of the aircraft from the selected runway, wherein said apparatus comprises a processor that compares a coordinate distance value representing a distance between the global coordinate values of the aircraft and the global coordinate values of the selected runway to a calculated distance value calculated based on the altitude of the aircraft above the runway and a predetermined glideslope, said predetermined glideslope based on predetermined operating parameters of the aircraft, and wherein said processor selects one of the coordinate distance value and the calculated distance value as the corrected distance between the aircraft and the selected runway based on a mathematical relationship between the coordinate and calculated distance values.

2. An apparatus according to claim 1, wherein said processor selects the larger of the coordinate distance value and the calculated distance value as the corrected distance between the aircraft and the selected runway.

3. An apparatus according to claim 1, wherein said processor receives an altitude of the aircraft and an elevation of the selected runway, and wherein said processor subtracts the altitude of the aircraft from the elevation of the runway to generate a value representing the altitude of the aircraft above the runway.

4. An apparatus according to claim 1, wherein the predetermined glideslope defines a predefined relationship between altitude and distance to the selected runway, such that said processor determines the calculated distance value to be equal to the distance to the selected runway associated with the altitude by the predefined relationship.

5. An apparatus according to claim 4, wherein the predefined glideslope defines a predefined relationship between altitude and distance to the selected runway expressed as:

6. A method for determining a corrected distance between an aircraft and a selected runway based on an altitude and distance of the aircraft from the selected runway, wherein said method comprises the steps of:

comparing a coordinate distance value representing a distance between the global coordinate values of the aircraft and the global coordinate values of the selected runway to a calculated distance value calculated based on the altitude of the aircraft above the runway and a predetermined glideslope, said predetermined glideslope based on predetermined operating parameters of the aircraft; and

selecting one of the coordinate distance and the calculated distance value as the corrected distance between the aircraft and the selected runway based on a mathematical relationship between the coordinate and calculated distance values.

7. A method according to claim 6, wherein said selecting step comprises selecting the larger of the coordinate distance value and the calculated distance value as the corrected distance between the aircraft and the selected runway.

8. A method according to claim 6 further comprising the steps of:

receiving an altitude of the aircraft and an elevation of the selected runway; and

subtracting the altitude of the aircraft from the elevation of the runway to generate a value representing the altitude of the aircraft above the runway.

9. A method according to claim 6, wherein the predetermined glideslope defines a predefined relationship between altitude and distance to the selected runway, wherein said method further comprises determining the calculated distance value to be equal to the distance to the selected runway associated with the altitude by the predefined relationship.

10. A method according to claim 9, wherein the predefined glideslope defines a predefined relationship between altitude and distance to the selected runway expressed as:

11. A computer program product for determining a corrected distance between an aircraft and a selected runway based on an altitude and distance of the aircraft from the selected runway, wherein the computer program product comprises:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer-readable program code means comprising;

first computer instruction means for comparing a coordinate distance value representing a distance between the global coordinate values of the aircraft and the global coordinate values of the selected runway to a calculated distance value calculated based on the altitude of the aircraft above the runway and a predetermined glideslope, said predetermined glideslope based on predetermined operating parameters of the aircraft; and

second computer instruction means for selecting one of the coordinate distance and the calculated distance value as the corrected distance between the aircraft and the selected runway based on a mathematical relationship between the coordinate and calculated distance values.

12. A computer program product as defined in claim 11, wherein said second computer instruction means comprises means for selecting the larger of the coordinate distance and the calculated distance value as the corrected distance between the aircraft and the selected runway.

13. A computer program product as defined in claim 11, wherein said computer-readable program code means further comprises:

third computer instruction means for receiving an altitude of the aircraft and an elevation of the selected runway; and

fourth computer instruction means for subtracting the altitude of the aircraft from the elevation of the runway to generate a value representing the altitude of the aircraft above the runway.

14. A computer program product as defined in claim 11, wherein the predetermined glideslope defines a predefined relationship between altitude and distance to the selected runway, wherein said computer-readable program code means further comprises fifth computer instruction means for determining the calculated distance value to be equal to the distance to the selected runway associated with the altitude by the predefined relationship.

15. A computer program product as defined in claim 14, wherein the predefined glideslope defines a predefined relationship between altitude and distance to the selected runway expressed as:

16. An apparatus for determining a corrected distance between an aircraft and a selected runway based on the position of the aircraft with respect to an envelope constructed about the selected runway representing a predetermined glideslope, said predetermined glideslope angle based on predetermined operating parameters of the aircraft, wherein said apparatus comprises a processor for selecting a coordinate distance value representing a distance between the global coordinate values of the aircraft and the global coordinate values of the selected runway if the aircraft is within the envelope and for selecting a calculated distance value calculated based on the altitude of the aircraft above the runway and the predetermined glideslope if the aircraft is positioned outside the envelope.

17. An apparatus according to claim 16, wherein said processor selects one of the coordinate distance and the calculated distance value as the corrected distance between the aircraft and the selected runway based on a mathematical relationship between the coordinate and calculated distance values.

18. An apparatus according to claim 17, wherein said processor selects the larger of the coordinate distance and the calculated distance value as the corrected distance between the aircraft and the selected runway.

19. An apparatus according to claim 16, wherein said processor receives an altitude of the aircraft and an elevation of the selected runway, and wherein said processor subtracts the altitude of the aircraft from the elevation of the runway to generate a value representing the altitude of the aircraft above the runway.

20. An apparatus according to claim 16, wherein the predetermined glideslope defines a predefined relationship between altitude and distance to the selected runway, such that said processor determines the calculated distance value to be equal to the distance to the selected runway associated with the altitude by the predefined relationship.

21. An apparatus according to claim 20, wherein the predefined glideslope defines a predefined relationship between altitude and distance to the selected runway expressed as:

22. An apparatus according to claim 16, wherein after said processor determines a corrected distance between an aircraft and a selected runway, said processor determines a look ahead distance value for use in a ground proximity warning system by comparing the corrected distance value to a ground speed look ahead distance value based upon the ground speed of the aircraft and the turning radius of the aircraft and a roll angle look ahead distance value based upon the roll angle of the aircraft and turning radius of the aircraft.

23. An apparatus according to claim 22, wherein said processor selects one of the calculated distance value, ground speed look ahead distance value, and the roll angle look ahead distance value as the look ahead distance value based on a mathematical relationship between the calculated distance value, ground speed look ahead distance value, and the roll angle look ahead distance value.

24. An apparatus according to claim 23, wherein said processor selects the smaller of the calculated distance value, ground speed look ahead distance value, and the roll angle look ahead distance value as the look ahead distance value.