Method for determining conflicting paths between mobile airborne vehicles and associated system and computer software program product

• US 6,564,149 B2
• Filed: 07/09/2001
• Issued: 05/13/2003
• Est. Priority Date: 07/10/2000
• Status: Active Grant

• Current Assignee: Garmin AT, Inc. (Garmin Limited)
• Original Assignee: United Parcel Service Of America Incorporated (United Parcel Service Incorporated)
• Inventors: Lai, Chih
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US09/901,415
• Publication Number:
  US 20020032528A1
• Time in Patent Office: 673 Days
• Field of Search: 701/301, 701/300, 701/14, 701/15, 701/16, 701/122, 701/121, 701/120, 340/945, 340/961, 340/963, 342/30, 342/455, 342/46, 342/29, 342/32, 342/36, 342/37
• US Class Current: 701/301
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 13/933 of aircraft or spacecraft
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G01S 7/06 Cathode-ray tube displays or other two dimensional or three-dimensional displays
• CPC Class Codes: G08G 5/0008 with other aircraft
• CPC Class Codes: G08G 5/0021 located in the aircraft
• CPC Class Codes: G08G 5/0078 for monitoring traffic from the aircraft radar or analogous systems specially adapted for traffic control G01S13/91

Abstract

A method of determining conflicting flight paths between a first and a second airborne vehicle is provided, wherein each vehicle comprises an aircraft-to-aircraft navigational communication system having a navigational device. First, a position and a velocity vector are determined for each of the airborne vehicles. A cylindrical volume is then defined about the first airborne vehicle. A separation distance is then determined between the vehicles at a selected time and using a great circle earth model. An accuracy factor is thereafter determined for the position of each vehicle. The separation distance is then modified by the accuracy factor. A determination is then made as to whether the modified separation distance is within the cylindrical volume about the first airborne vehicle during a time range to thereby determine whether conflicting flight paths exist between the vehicles. An associated system and computer software program product are also provided.

Claims

1. A method of determining conflicting flight paths between a first airborne vehicle and a second airborne vehicle, the vehicles being adapted to be airborne above the earth, the earth being shaped as an oblate spheroid having a curvature, said method comprising:

determining a position and a velocity vector for each of the first airborne vehicle and the second airborne vehicle;

defining a cylindrical volume about the first airborne vehicle, the first airborne vehicle being centrally disposed therein;

determining a separation distance between the first airborne vehicle and the second airborne vehicle at a selected time, the separation distance being at least partially determined from the position and the velocity vector of each vehicle and being adjusted with respect to the curvature of the earth using a great circle earth model;

determining an accuracy factor for the position of each vehicle;

modifying the separation distance by the accuracy factor; and

determining whether the modified separation distance is within the cylindrical volume about the first airborne vehicle during a time range so as to determine whether conflicting flight paths exist between the first airborne vehicle and the second airborne vehicle.

2. A method according to claim 1 wherein each vehicle comprises an Automatic Dependence Surveillance-Broadcast (ADS-B) system having a Global Navigation Satellite System (GNSS) device and determining a position and a velocity vector further comprises determining a position and a velocity vector for each vehicle with the respective GNSS device.

3. A method according to claim 2 wherein determining an accuracy factor further comprises determining an accuracy factor for the position of each vehicle with the respective ADS-B system.

4. A method according to claim 2 wherein determining an accuracy factor further comprises determining an accuracy factor for each vehicle with the respective ADS-B system, at least one of the ADS-B systems having a GPS device.

5. A method according to claim 2 wherein determining an accuracy factor further comprises determining a Navigation Uncertainty Category for Position (NUC_P) factor for each vehicle from the respective ADS-B system.

6. A method according to claim 2 wherein modifying the separation distance further comprises modifying the separation distance by a high limit of a Horizontal Protection Limit (HPL) factor corresponding to a Navigation Uncertainty Category for Position (NUC_P) factor for each vehicle from the respective ADS-B system.

7. A method according to claim 2 wherein directing an alarm to be issued further comprises directing an alarm to be issued with an alert characteristic determined according to a priority level corresponding to a priority condition in a list of priority conditions, the priority level being at least partially determined from the ADS-B system of each vehicle and the alarm comprising at least one of a visual alert and an aural alert.

8. A method according to claim 1 wherein defining a cylindrical volume about the first airborne vehicle further comprises defining a cylindrical volume about the first airborne vehicle with the cylindrical volume having a geocentric axis extending through the first airborne vehicle.

9. A method according to claim 1 further comprising directing an alarm to be issued if the modified separation distance is within the cylindrical volume so as to indicate conflicting flight paths between the first airborne vehicle and the second airborne vehicle.

10. A method according to claim 1 wherein determining the position and the velocity vector further comprises determining the position and the velocity vector for each vehicle with a Global Positioning System (GPS) device.

11. A method according to claim 1 further comprising determining a common time reference with respect to the first airborne vehicle and the second airborne vehicle.

12. A method according to claim 1 wherein determining a separation distance further comprises determining a separation distance between the first airborne vehicle and the second airborne vehicle as a function of time so as to define a flight path for each vehicle.

13. A method according to claim 1 wherein determining a separation distance further comprises determining a separation distance adjusted with respect to the curvature of the earth using a great circle earth model by correlating the position and the velocity vector of the first airborne vehicle to a polar reference and then modifying the position and the velocity vector of the second airborne vehicle by an angular separation between the vehicles with respect to the polar reference.

14. A method according to claim 1 further comprising determining whether the modified separation distance was within the cylindrical volume about the first airborne vehicle at a time preceding the time range.

15. A method according to claim 1 further comprising determining whether the modified separation distance will be within the cylindrical volume about the first airborne vehicle at a time beyond the time range.

16. A method according to claim 1 further comprising adjusting the cylindrical volume and the time range according to an altitude of the first airborne vehicle.

17. A method according to claim 1 wherein defining a cylindrical volume further comprises defining a cylindrical volume about the first airborne vehicle corresponding to a desired separation distance between the first airborne vehicle and the second airborne vehicle.

18. A method according to claim 1 further comprising monitoring the separation distance between the first airborne vehicle and the second airborne vehicle, if the modified separation distance is within the cylindrical volume, so as to determine a status of the conflicting flight paths between the first airborne vehicle and the second airborne vehicle.

19. A method according to claim 1 further comprising altering the flight path of the first airborne vehicle until the modified separation distance is outside of the cylindrical volume.

20. A system for determining conflicting flight paths between a first airborne vehicle and a second airborne vehicle, the vehicles being adapted to be airborne above the earth, the earth being shaped as an oblate spheroid having a curvature, said system comprising:

a computer device housed by the first airborne vehicle, the computer device comprising;

a processing portion for determining a position and a velocity vector for each of the first airborne vehicle and the second airborne vehicle;

a processing portion for defining a cylindrical volume about the first airborne vehicle, the first airborne vehicle being centrally disposed therein;

a processing portion for determining a separation distance between the first airborne vehicle and the second airborne vehicle at a selected time, the separation distance being at least partially determined from the position and the velocity vector of each vehicle and being adjusted with respect to the curvature of the earth using a great circle earth model;

a processing portion for determining an accuracy factor for the position of each vehicle,

a processing portion for modifying the separation distance by the accuracy factor; and

a processing portion for determining whether the modified separation distance is within the cylindrical volume about the first airborne vehicle during a time range so as to determine whether conflicting flight paths exist between the first airborne vehicle and the second airborne vehicle.

21. A system according to claim 20 further comprising an Automatic Dependence Surveillance-Broadcast (ADS-B) system housed by each vehicle, each ADS-B system being capable of communicating with the computer device.

22. A system according to claim 21 further comprising a Global Navigation Satellite System (GNSS) device in communication with each ADS-B system.

23. A system according to claim 22 wherein at least one GNSS device further comprises a Global Positioning System (GPS) device.

24. A system according to claim 22 wherein the processing portion for determining a position and a velocity vector is further capable of determining a position and a velocity vector with the respective GNSS device.

25. A system according to claim 21 wherein the ADS-B system housed by the first airborne vehicle further comprises a subsystem capable of receiving an ADS-B broadcast from the ADS-B system housed by the second airborne vehicle.

26. A system according to claim 21 wherein the processing portion for determining an accuracy factor is further capable of determining an accuracy factor with the respective ADS-B system.

27. A system according to claim 21 wherein the processing portion for determining an accuracy factor is further configured to determine a Navigational Uncertainty for Position (NUC_P) factor for each vehicle from the respective ADS-B system.

28. A system according to claim 21 wherein the processing portion for modifying the separation distance is further configured to modify the separation distance by a high limit of a Horizontal Protection Limit (HPL) factor corresponding to a Navigational Uncertainty for Position (NUC_P) factor for each vehicle from the respective ADS-B system.

29. A system to claim 20 wherein the processing portion for defining a cylindrical volume is further capable defining a cylindrical volume about the first airborne vehicle such that the cylindrical volume has a geocentric axis extending through the first airborne vehicle.

30. A system according to claim 20 wherein the computer device further comprises a processing portion for directing an alarm to be issued if the modified separation distance is within the cylindrical volume so as to indicate conflicting flight paths between the first airborne vehicle and the second airborne vehicle.

31. A system according to claim 30 wherein the processing portion for directing an alarm to be issued is further configured to direct an alarm to be issued with an alert characteristic determined according to a priority level corresponding to a priority condition in a list of priority conditions, the alarm comprising at least one of a visual alert and an aural alert.

32. A system according to claim 20 wherein the computer device further comprises a processing portion for determining a common time reference with respect to the first airborne vehicle and the second airborne vehicle.

33. A system according to claim 20 wherein the processing portion for determining a separation distance is further capable of determining a separation distance as the function of time so as to define a flight path for each vehicle.

34. A system according to claim 20 wherein the processing portion for determining a separation distance is further capable of determining a separation distance adjusted with respect to the curvature of the earth using a great circle earth model by correlating the position and the velocity vector of the first airborne vehicle to a polar reference and then modifying the position and the velocity vector of the second airborne vehicle by an angular separation between the vehicles with respect to the polar reference.

35. A system according to claim 20 wherein the computer device further comprises a processing portion for determining at least one of whether the modified separation distance was within the cylindrical volume about the first airborne vehicle at a time preceding the time range and whether the modified separation distance will be within the cylindrical volume about the first airborne vehicle at a time beyond the time range.

36. A system according to claim 20 wherein the computer device further comprises a processing portion for adjusting the cylindrical volume and the time range according to an altitude of the first airborne vehicle.

37. A system according to claim 20 wherein the processing portion for defining a cylindrical volume is further configured to define a cylindrical volume about the first airborne vehicle corresponding to a desired separation distance between the first airborne vehicle and the second airborne vehicle.

38. A system according to claim 20 wherein the computer device further comprises a processing portion for monitoring the separation distance between the first airborne vehicle and the second airborne vehicle, if the modified separation distance is within the cylindrical volume, so as to determine a status of the conflicting flight paths between the first airborne vehicle and the second airborne vehicle.

39. A system according to claim 20 wherein the computer device further comprises a processing portion for directing the altering of the flight path of the first airborne vehicle until the modified separation distance is outside of the cylindrical volume.

40. A computer software program product capable of being executed by a computer device so as to determine conflicting flight paths between a first airborne vehicle and a second airborne vehicle, the vehicles being adapted to be airborne above the earth, the earth being shaped as an oblate spheroid having a curvature, the computer software program product comprising:

an executable portion capable of determining a position and a velocity vector for each of the first airborne vehicle and the second airborne vehicle;

an executable portion capable of defining a cylindrical volume about the first airborne vehicle such that the first airborne vehicle is centrally disposed therein;

an executable portion capable of determining a separation distance between the first airborne vehicle and the second airborne vehicle at a selected time, the separation distance being at least partially determined from the position and the velocity vector of each vehicle and being adjusted with respect to the curvature of the earth using a great circle earth model;

an executable portion capable of determining an accuracy factor for the position of each vehicle;

an executable portion capable of modifying the separation distance by the accuracy factor; and

an executable portion capable of determining whether the modified separation distance is within the cylindrical volume about the first airborne vehicle during a time range so as to determine whether conflicting flight paths exist between the first airborne vehicle and the second airborne vehicle.

41. A computer software program product according to claim 40 wherein each vehicle comprises an Automatic Dependence Surveillance-Broadcast (ADS-B) system with a Global Navigation Satellite System (GNSS) device in communication therewith and the computer software program product further comprises an executable portion capable of directing communication between the computer device and the ADS-B system of each vehicle.

42. A computer software program product according to claim 41 wherein the executable portion capable of determining a position and a velocity vector is further capable of processing information from the respective GNSS devices so as to determine the position and the velocity vector of the corresponding vehicle.

43. A computer software program product according to claim 41 wherein the executable portion capable of determining an accuracy factor is further capable of processing information from the respective ADS-B systems so as to determine the accuracy factor of the corresponding vehicle.

44. A computer software program product according to claim 41 wherein the executable portion capable of determining a position and a velocity vector is further capable of determining a position and a velocity vector from at least one GNSS device comprising a Global Positioning System (GPS) device.

45. A computer software program product according to claim 41 wherein the executable portion capable of determining an accuracy factor is further capable of processing ADS-B broadcast information received by the ADS-B system housed by the first airborne vehicle to determine the accuracy factor.

46. A computer software program product according to claim 41 wherein the executable portion capable of determining an accuracy factor is further capable of determining a Navigational Uncertainty for Position (NUC_P) factor for each vehicle from the respective ADS-B system.

47. A computer software program product according to claim 41 wherein the executable portion capable of modifying the separation distance is further capable of modifying the separation distance by a high limit of a Horizontal Protection Limit (HPL) factor corresponding to a Navigational Uncertainty for Position (NUC_P) factor for each vehicle from the respective ADS-B system.

48. A computer software program product according to claim 40 wherein the executable portion capable of defining a cylindrical volume is further capable of defining a cylindrical volume having a geocentric axis extending through the first airborne vehicle.

49. A computer software program product according to claim 40 further comprising an executable portion capable of directing an alarm to be issued if the modified separation distance is within the cylindrical volume so as to indicate conflicting flight paths between the first airborne vehicle and the second airborne vehicle.

50. A computer software program product according to claim 49 wherein the executable portion capable of directing an alarm to be issued is further capable of directing an alarm to be issued with an alert characteristic determined according to a priority level corresponding to a priority condition in a list of priority conditions, the alarm comprising at least one of a visual alert and an aural alert.

51. A computer software program product according to claim 40 further comprising an executable portion capable of determining a common time reference with respect to the first airborne vehicle and the second airborne vehicle.

52. A computer software program product according to claim 40 wherein the executable portion capable of determining a separation distance is further capable of determining a separation distance as a function of time so as to define a flight path for each vehicle.

53. A computer software program product according to claim 40 wherein the executable portion capable of determining a separation distance is further capable of determining a separation distance adjusted with respect to the curvature of the earth using a great circle earth model by correlating the position and the velocity vector of the first airborne vehicle to a polar reference and then modifying the position and the velocity vector of the second airborne vehicle by an angular separation between the vehicles with respect to the polar reference.

54. A computer software program product according to claim 40 further comprising an executable portion capable of determining at least one of whether the modified separation distance was within the cylindrical volume about the first airborne vehicle at a time preceding the time range and whether the modified separation distance will be within the cylindrical volume about the first airborne vehicle at a time beyond the time range.

55. A computer software program product according to claim 40 further comprising an executable portion capable of adjusting the cylindrical volume and the time range according to an altitude of the first airborne vehicle.

56. A computer software program product according to claim 40 wherein the executable portion capable of defining a cylindrical volume is further capable of defining a cylindrical volume about the first airborne vehicle corresponding to a desired separation distance between the first airborne vehicle and the second airborne vehicle.

57. A computer software program product according to claim 40 further comprising an executable portion capable of monitoring the separation distance between the first airborne vehicle and the second airborne vehicle, if the modified separation distance is within the cylindrical volume, so as to determine a status of the conflicting flight paths between the first airborne vehicle and the second airborne vehicle.

58. A computer software program product according to claim 40 further comprising an executable portion capable of directing the altering of the flight path of the first airborne vehicle until the modified separation distance is outside of the cylindrical volume.