Flight navigation holding pattern entry algorithms

• US 20040230351A1
• Filed: 05/15/2003
• Published: 11/18/2004
• Est. Priority Date: 05/15/2003
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Rumbo, Jim R., Hill, Gregory S., Hadley, John C., Bouanani, Adib, Gaier, Chad E.
• Granted Patent: US 7,003,383 B2
• Time in Patent Office: Days
• US Class Current: 701/3
• CPC Class Codes: G05D 1/0202 specially adapted to aircraft

Abstract

The present invention provides a set of holding pattern entry algorithms used to define flight segments for entry into holding patterns. These geometries preferably describe the specific location and distance of various segments used in the holding pattern and holding pattern racetrack, with each segment defined as a curved or straight segment between endpoints. The algorithms also preferably include criteria used to determine entry extension, maximum initial turn angle, and minimum distance between a hold fix and an entry turn point. The geometry also preferably extends entry distance to avoid excessive iterative calculations. The algorithms are preferably utilized by a flight management system and method that determines segment sequencing during entry into holding patterns and the holding patterns themselves. The flight management system and method monitors the aircraft'"'"'s progress along the active segment of the flight plan to determine what is the appropriate next segment in the algorithm and when to switch control from the active segment to the next segment.

Claims

1. A hold entry algorithm for a teardrop holding pattern entry, the hold entry algorithm comprising:

a) a teardrop turn 1 segment;

b) a teardrop outbound segment following the teardrop turn 1 segment, the teardrop outbound segment having a length equal to the smaller of a hold racetrack outbound distance and a default leg distance, and wherein if the outbound segment length is less than a defined minimum distance the outbound segment length is extended to the greater of the hold racetrack outbound distance or the default leg length distance;

c) a teardrop turn 2 segment following the teardrop outbound segment; and

d) a teardrop inbound segment following the teardrop turn 2 segment.

2. The hold entry algorithm of claim 1 wherein the teardrop turn 1 segment comprises a non-standard curved path transition having a radius different than a radius of a racetrack holding pattern.

3. The hold entry algorithm of claim 1 wherein the teardrop turn 2 segment has a radius equal to a racetrack holding pattern radius.

4. The hold entry algorithm of claim 1 wherein the defined minimum distance comprises a required roll anticipation distance.

5. The hold entry algorithm of claim 1 wherein the teardrop inbound segment is calculated to reflect extension of the teardrop outbound segment.

6. The hold entry algorithm of claim 1 wherein the default leg distance is defined as:

7. A hold entry algorithm for a parallel holding pattern entry, the hold entry algorithm comprising,

e) a parallel turn 1 segment;

f) a parallel outbound segment following the parallel turn 1 segment;

g) a parallel turn 2 segment following the parallel outbound segment;

h) a parallel inbound segment following the parallel turn 2 segment, the parallel inbound segment having an initial length set to the smaller of a default leg distance or a racetrack holding pattern leg length, and wherein the parallel outbound segment is extended to ensure that the parallel inbound segment has a length at least as long as the -red roll anticipation distance; and

i) a parallel turn 3 segment following the parallel inbound segment.

8. The hold entry algorithm of claim 7 wherein the parallel turn 2 segment has a radius equal to a racetrack holding pattern radius.

9. The hold entry algorithm of claim 7 wherein the parallel inbound segment has a length defined as

10. The hold entry algorithm of claim 7 wherein the default leg distance is defined as:

11. A navigation system, the navigation system comprising:

j) hold entry algorithm for a teardrop holding pattern entry, the hold entry algorithm including;

i) a teardrop turn 1 segment;

ii) a teardrop outbound segment following the teardrop turn 1 segment, the teardrop outbound segment having a length equal to the smaller of a hold racetrack outbound distance and a default leg distance, and wherein if the outbound segment length is less than a defined minimum distance the outbound segment length is extended to the greater of the hold racetrack outbound distance or the default leg length distance;

iii) a teardrop turn 2 segment following the teardrop outbound segment; and

iv) a teardrop inbound segment following the teardrop turn 2 segment; and

k) a sequencing system, the sequencing system monitoring aircraft progress along an active segment in the hold entry algorithm, the sequencing system evaluating the teardrop turn 1 segment, the teardrop outbound segment, the teardrop turn 2 segment and the teardrop inbound segment to determine which segment meets a control criterion, the sequencing system controlling to selected segments from the plurality of segments as the selected segments meet the control criterion.

12. The navigation system of claim 11 wherein the teardrop turn 1 segment comprises a non-standard curved path transition having a radius different than a radius of a racetrack holding pattern, and wherein the teardrop turn 2 segment has a radius equal to a racetrack holding pattern radius.

13. The navigation system of claim 11 wherein the defined minimum distance comprises a required roll anticipation distance.

14. The navigation system of claim 11 wherein the teardrop inbound segment is calculated to reflect extension of the teardrop outbound segment.

15. The navigation system of claim 11 wherein the default leg distance is defined as:

16. The navigation system of claim 11 wherein the sequencing system sequences to a next segment when the aircraft is following the current segment within a specified error distance and when the aircraft crosses a wayline.

17. The navigation system of claim 11 wherein the sequencing system sequences to the next segment when the aircraft is following the current segment beyond the cent specified error distance and the aircraft is on track to intercept the next segment.

18. The navigation system of claim 11 wherein the current specified error distance is equal to a turn radius of a holding pattern.

19. A navigation system, the navigation system comprising:

l) hold entry algorithm for a teardrop holding pattern entry, the hold entry algorithm including;

i) a parallel turn 1 segment;

ii) a parallel outbound segment following the parallel turn 1 segment;

iii) a parallel turn 2 segment following the parallel outbound segment;

iv) a parallel inbound segment following the parallel turn 2 segment, the parallel inbound segment having an initial length set to the smaller of a default leg distance or a racetrack holding pattern leg length, and wherein the parallel outbound segment is extended to ensure that the parallel inbound segment has a length at least as long as the required roll anticipation distance; and

v) a parallel turn 3 segment following the parallel inbound segment; and

m) a sequencing system, the sequencing system monitoring aircraft progress along an active segment in the hold entry algorithm, the sequencing system evaluating the parallel turn 1 segment, the parallel outbound segment, the parallel turn 2 segment, the parallel inbound segment and the parallel turn 3 segment to determine which segment meets a control criterion, the sequencing system controlling to selected segments from the plurality of segments as the selected segments meet the control criterion.

20. The navigation system of claim 19 wherein the parallel turn 2 segment has a radius equal to a racetrack holding pattern radius.

21. The navigation system of claim 19 wherein the parallel inbound segment has a length defined as

22. The navigation system of claim 19 wherein the default leg distance is defined as:

23. The navigation system of claim 19 wherein the sequencing system sequences to a next segment when the aircraft is following the current segment within a specified error distance and when the aircraft crosses a wayline.

24. The navigation system of claim 19 wherein the sequencing system sequences to the next segment when the aircraft is following the current segment beyond the current specified error distance and the aircraft is on track to intercept the next segment.

25. The navigation system of claim 19 wherein the current specified error distance is equal to a turn radius of a holding pattern.