Surface hold advisor using critical sections

• US 8,566,016 B2
• Filed: 12/13/2010
• Issued: 10/22/2013
• Est. Priority Date: 05/13/2010
• Status: Active Grant

• Current Assignee: Architectural technology Inc.
• Original Assignee: Saab Sensis Corp. (Saab AB)
• Inventors: Law, Caleb Hoi Kei, Hsiao, Thomas Kun-Lung, Mittler, Nathan C., Couluris, George J.
• Primary Examiner(s): Amin, Bhavesh V
• Application Number:
  US12/966,293
• Publication Number:
  US 20110282565A1
• Time in Patent Office: 1,044 Days
• Field of Search: 701/1, 701 3- 18, 701116-122, 701400-541, 701301-302, 340901-905, 340/906, 340909-924, 340/931, 340/932, 340933-943, 340945-983, 340988-996
• US Class Current: 701/301
• CPC Class Codes: G08G 5/065 Navigation or guidance aids, e.g. for taxiing or rolling

Abstract

The Surface Hold Advisor Using Critical Sections is a system and method for providing hold advisories to surface controllers to prevent gridlock and resolve crossing and merging conflicts among vehicles traversing a vertex-edge graph representing a surface traffic network on an airport surface. The Advisor performs pair-wise comparisons of current position and projected path of each vehicle with other surface vehicles to detect conflicts, determine critical sections, and provide hold advisories to traffic controllers recommending vehicles stop at entry points to protected zones around identified critical sections. A critical section defines a segment of the vertex-edge graph where vehicles are in crossing or merging or opposite direction gridlock contention. The Advisor detects critical sections without reference to scheduled, projected or required times along assigned vehicle paths, and generates hold advisories to prevent conflicts without requiring network path direction-of-movement rules and without requiring rerouting, rescheduling or other network optimization solutions.

Claims

1. A method for preventing conflicts between vehicles in a vehicle traffic network on an airport surface, the method comprising:

defining, via a processor the traffic network on an airport surface, the traffic network comprising at least a plurality of taxiways, runways and intersections therebetween;

determining, via a processor a location and an assigned path for each vehicle in the traffic network for which location and path data are provided;

searching along the assigned path and identifying a conflict where assigned paths for two vehicles merge, cross or intersect from opposing directions on the airport surface;

designating a critical section on the airport surface for each identified conflict and defining a protected zone for each identified critical section;

determining, via a processor a hold requirement for each identified conflict, the hold requirement defining a projected hold position for stopping one of the two vehicles in a conflicting pair at an entry point to the protected zone for the identified critical section;

determining, via a processor whether any of the projected hold positions for the vehicles intrudes into the protected zone;

repositioning projected hold positions intruding into the protected zone; and

providing a hold advisory to a traffic controller, said hold advisory comprising the hold requirement to stop all but one vehicle or all vehicles at entry points to the protected zone for each identified critical section on the airport surface, wherein identifying said conflict comprises;

pairing one vehicle with each of the other vehicles in the traffic network, comparing, via a processor, the assigned path for the one vehicle to the assigned path for the other vehicle in the pair to identify common vertexes;

identifying each common vertex as a part of a critical section on the airport surface;

repeating the pairing and comparing, via a processor, of the assigned path for the one vehicle to the assigned paths for each of the remaining other vehicles in the traffic network; and

repeating the pairing and comparing of the assigned paths for each of the remaining other vehicles in pairs in the traffic network.

2. The method of claim 1, wherein searching along the assigned path commences at a vertex most recently crossed by each vehicle in the pair and moves forward along a remaining portion of the assigned path for each vehicle, wherein the remaining portion includes a current position of the vehicle.

3. The method of claim 2, wherein the vertex most recently crossed, the current position and remaining portion of the assigned path for each vehicle are provided as input data.

4. The method of claim 1, wherein the critical section is a crossing critical section when the assigned paths for each of the vehicles in the pair intersect a single vertex.

5. The method of claim 4, wherein the protected zone of the crossing critical section comprises an area containing at least the identified single common vertex.

6. The method of claim 1, wherein the critical section is a merging critical section when the assigned paths for each of the vehicles in the pair have more than one common vertex and are moving in the same direction.

7. The method of claim 6, wherein the protected zone of the merging critical section comprises an area containing at least a first common vertex identified along the assigned paths for each of the vehicles.

8. The method of claim 1, wherein the critical section is a gridlock critical section where the assigned paths for each of the vehicles in the pair have more than one common vertex and are moving in different directions.

9. The method of claim 8, wherein the protected zone of the gridlock critical section comprises an area containing a first common vertex along the assigned path and direction of travel for the one vehicle, an area containing a first common vertex along the assigned path and direction of travel for the another vehicle and an area containing the more than one common vertexes identified and the edges between each of the more than one common vertexes.

10. The method of claim 1, wherein the protected zone is blocked when any part of a vehicle occupies any part of the protected zone.

11. The method of claim 1, further comprising repositioning the projected hold position when a projected hold position causes the held vehicle to block at least a portion of a protected zone, wherein the repositioned projected hold position is an entry point for the vehicle to the protected zone.

12. The method of claim 1, wherein repositioning the projected hold position comprises repositioning a hold position generated by an external function.

13. The method of claim 1, further comprising applying user-defined prioritization rules to assign projected hold positions to vehicles when more than one vehicle is not assigned a projected hold position.

14. The method of claim 1, wherein repositioning the projected hold position further comprises determining whether the repositioned hold position causes the held vehicle to block at least a portion of a protected zone and repositioning the repositioned hold position when the repositioned hold position causes the held vehicle to block at least a portion of a protected zone.

15. The method of claim 1, wherein said hold advisories stop vehicles at an earliest hold position along the vehicle'"'"'s path from the current position of the vehicle.

16. The method of claim 1, wherein said hold position selected for each of the vehicles are provided to traffic controllers in surface air traffic control systems.

17. The method of claim 1, wherein the airport surface traffic network is a graph, each of the plurality of intersections is a vertex on the graph and each of the runways and taxiways is an edge on the graph.

18. The method of claim 1, wherein the hold requirement permits no more than one vehicle to move uninterrupted through the identified critical section.

19. A system for preventing conflicts between vehicles in a vehicle traffic network on an airport surface comprising:

one or more surveillance systems covering a traffic network on an airport surface, the traffic network comprising at least a plurality of taxiways, runways and intersections therebetween; and

a computer running a program for preventing conflicts, wherein the computer

receives at least location data and path data from the one or more surveillance systems;

determines a location and an assigned path for each vehicle in the traffic network for which location and path data are provided;

searches along the assigned path and identifies a conflict where assigned paths for two vehicles merge, cross or intersect from opposing directions on the airport surface;

designates a critical section on the airport surface for each identified conflict and defines a protected zone for each identified critical section;

determines a hold requirement for each identified conflict, the hold requirement defines a projected hold position for stopping one of the two vehicles in a conflicting pair at an entry point to the protected zone for the identified critical section;

determines whether any of the projected hold positions for the vehicles intrudes into the protected zone;

repositions projected hold positions that intrude into the protected zone; and

provides a hold advisory to a traffic controller, said hold advisory

comprising the hold requirement to stop all but one vehicle or all vehicles at entry points to the protected zone for each identified critical section on the airport surface, wherein the computer identifies a conflict by;

pairing one vehicle with each of the other vehicles in the traffic network;

comparing the assigned path for the one vehicle to the assigned path for the other vehicle in the pair to identify common vertexes;

identifying each common vertex as a part of a critical section on the airport surface;

repeating the pairing and comparing of the assigned path for the one vehicle to the assigned paths for each of the remaining other vehicles in the traffic network; and

repeating the pairing and comparing of the assigned paths for each of the remaining other vehicles in pairs in the traffic network.

20. The system of claim 19, wherein the computer searches along the assigned path starting at a vertex most recently crossed by each vehicle in the pair and moves forward along a remaining portion of the assigned path for each vehicle, the remaining portion of the assigned path including a current position of the vehicle.

21. The system of claim 20, wherein the vertex most recently crossed, the current position and remaining portion of the assigned path for each vehicle are provided as input data to the computer by at least the one or more surveillance systems.

22. The system of claim 19, wherein the computer identifies the critical section as a crossing critical section when the assigned paths for each of the vehicles in the pair intersect a single vertex.

23. The system of claim 22, wherein the computer determines the protected zone of the crossing critical section comprises an area containing at least the identified single common vertex.

24. The system of claim 19, wherein the computer identifies the critical section as a merging critical section when the assigned paths for each of the vehicles in the pair have more than one common vertex and are moving in the same direction.

25. The system of claim 23, wherein the computer determines the protected zone of the merging critical section comprises an area containing at least a first common vertex identified along the assigned paths for each of the vehicles.

26. The system of claim 19, wherein the computer identifies the critical section as a gridlock critical section where the assigned paths for each of the vehicles in the pair have more than one common vertex and are moving in different directions.

27. The system of claim 26, wherein the computer determines the protected zone of the gridlock critical section comprises an area containing a first common vertex along the assigned path and direction of travel for the one vehicle, an area containing a first common vertex along the assigned path and direction of travel for the another vehicle and an area containing the more than one common vertexes identified and the edges between each of the more than one common vertexes.

28. The system of claim 19, wherein the computer determines that the protected zone is blocked when any part of a vehicle occupies any part of the protected zone.

29. The system of claim 19, further comprising the computer repositions the projected hold position when a projected hold position causes the held vehicle to block at least a portion of a protected zone, wherein the repositioned projected hold position is an entry point for the vehicle to the protected zone.

30. The system of claim 19, wherein the computer repositioning the projected hold position comprises repositioning a hold position generated by an external function.

31. The system of claim 19, further comprising the computer applies user-defined prioritization rules to assign projected hold positions to vehicles when more than one vehicle is not assigned a projected hold position.

32. The system of claim 19, wherein the computer determines whether the repositioned hold position causes the held vehicle to block at least a portion of a protected zone and repositions the repositioned hold position when the repositioned hold position causes the held vehicle to block at least a portion of a protected zone.

33. The system of claim 19, wherein said hold advisories stop the one or more vehicles at an earliest hold position along the vehicle'"'"'s path from the current position of the vehicle.

34. The system of claim 19, wherein the computer determines a hold position and displays the hold position selected for each of the one or more vehicles to traffic controllers in a surface traffic control system.

35. The system of claim 19, wherein the computer defines the airport surface traffic network on a graph with each of the plurality of intersections as a vertex on the graph and each of the runways and taxiways as an edge on the graph.

36. The system of claim 19, wherein the hold requirement permits no more than one vehicle to move uninterrupted through the identified critical section.