Aircraft identification and docking guidance systems

• US 20030060998A1
• Filed: 04/29/2002
• Published: 03/27/2003
• Est. Priority Date: 07/17/1997
• Status: Active Grant

• Current Assignee: ADB Safegate Sweden AB (ADB Safegate BVBA)
• Original Assignee: Safegate International AB (ADB Safegate BVBA)
• Inventors: Millgard, Lars
• Granted Patent: US 6,807,511 B2
• Time in Patent Office: Days
• US Class Current: 702/127
• CPC Class Codes: B64F 1/305 Bridges extending between terminal building and aircraft, e.g. telescopic, vertically adjustable
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/875 for determining attitude
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/933 of aircraft or spacecraft
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06V 10/255 Detecting or recognising potential candidate objects based on visual cues, e.g. shapes
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: G08G 5/0026 located on the ground
• 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
• CPC Class Codes: G08G 5/065 Navigation or guidance aids, e.g. for taxiing or rolling

Abstract

A laser range finder (LRF) is used to identify an aircraft approaching a gate. The LRF is directed at the aircraft, and from the echoes, a profile is derived and compared to known profiles. To distinguish among aircraft with similar profiles, the LRF is directed at a volume in which a feature such as an engine is expected and at another volume in which the engine is not expected. The echoes from the two volumes are used to determine whether the engine is in its expected location. If so, the aircraft is identified as the correct type and is allowed to dock at the gate. Otherwise, the aircraft is stopped. The nose height can be used as yet another identifying criterion.

Claims

1. A system for determining whether a detected object is a known object, the known object having a known profile and also having a known feature at a known location, the system comprising:

projecting means for projecting light pulses onto the detected object;

collecting means for collecting light pulses reflected off the detected object and for detecting a shape of the detected object in accordance with the light pulses;

comparing means for comparing the detected shape with a profile corresponding to the known shape and for determining whether the detected shape corresponds to the known shape; and

identifying means for identifying whether the detected object is the known object by determining whether the detected object has the known feature at the known location.

2. The system of claim 1, wherein:

for the known object, an inner volume is defined so as to contain the known feature, and an outer volume is defined so as not to contain the known feature;

the identifying means determines whether the detected object has the known feature in the known location in accordance with a number of light pulses reflected from within the inner volume and a number of light pulses reflected from within the outer volume.

3. The system of claim 2, wherein the outer volume is defined to surround the inner volume.

4. The system of claim 2, wherein the identifying means determines whether the detected object has the known feature in the known location in accordance with whether

Vi/(Vi+Vo)>

T,

where;

Vi=the number of light pulses reflected from the inner volume;

Vo=the number of light pulses reflected from the outer volume; and

T=a predetermined threshold value.

5. The system of claim 4, wherein T=0.7.

6. The system of claim 2, wherein the identifying means controls the projecting means to project light pulses into the inner volume and the outer volume.

7. The system of claim 1, wherein:

the known object comprises a nose with a known nose height; and

the identifying means further identifies whether the detected object is the known object by detecting a nose height of the detected object and comparing the detected nose height to the known nose height.

8. The system of claim 7, wherein the identifying means compares the detected nose height to the known nose height by taking a difference between the detected nose height and the known nose height.

9. The system of claim 8, wherein the identifying means identifies the detected object as the known object only if the difference is less than or equal to a threshold difference.

10. The system of claim 9, wherein the threshold difference is 0.5 m.

11. The system of claim 1, wherein the comparing means determines a yaw angle of the detected object.

12. The system of claim 11, wherein the comparing means rotates the profile corresponding to the known shape by an angle equal to the yaw angle.

13. A method for determining whether a detected object is a known object, the known object having a known profile and also having a known feature at a known location, the method comprising:

(a) projecting light pulses onto the detected object;

(b) collecting light pulses reflected off the detected object and for detecting a shape of the detected object in accordance with the light pulses;

(c) comparing the detected shape with a profile corresponding to the known shape and for determining whether the detected shape corresponds to the known shape; and

(d) identifying whether the detected object is the known object by determining whether the detected object has the known feature at the known location.

14. The method of claim 13, wherein:

for the known object, an inner volume is defined so as to contain the known feature, and an outer volume is defined so as not to contain the known feature;

said step of identifying comprises determining whether the detected object has the known feature in the known location in accordance with a number of light pulses reflected from within the inner volume and a number of light pulses reflected from within the outer volume.

15. The method of claim 14, wherein the outer volume is defined to surround the inner volume.

16. The method of claim 14, wherein said step of identifying comprises determining whether the detected object has the known feature in the known location in accordance with whether

Vi/(Vi+Vo)>

T,

where;

Vi=the number of light pulses reflected from the inner volume;

Vo=the number of light pulses reflected from the outer volume; and

T=a predetermined threshold value.

17. The method of claim 16, wherein T=0.7.

18. The method of claim 14, wherein said step of identifying comprises controlling said step of projecting to project light pulses into the inner volume and the outer volume.

19. The method of claim 13, wherein:

the known object comprises a nose with a known nose height; and

said step of identifying comprises further identifying whether the detected object is the known object by detecting a nose height of the detected object and comparing the detected nose height to the known nose height.

20. The method of claim 19, wherein said step of identifying comprises comparing the detected nose height to the known nose height by taking a difference between the detected nose height and the known nose height.

21. The method of claim 20, wherein said step of identifying identifies the detected object as the known object only if the difference is less than or equal to a threshold difference.

22. The method of claim 21, wherein the threshold difference is 0.5 m.

23. The method of claim 13, wherein said step of comparing comprises determining a yaw angle of the detected object.

24. The method of claim 23, wherein said step of comparing further comprises rotating the profile corresponding to the known shape by an angle equal to the yaw angle.

25. A system for determining a yaw angle of a detected object, the system comprising:

projecting means for projecting light pulses onto the detected object;

collecting means for collecting light pulses reflected off the detected object and for detecting a shape of the detected object in accordance with the light pulses; and

angle determining means for determining the yaw angle from the shape detected by the collecting means.

26. The system of claim 25, wherein the detected object comprises a nose having a nose tip, and wherein the angle determining means determines the yaw angle from a portion of the shape which is adjacent to the nose tip.

27. The system of claim 26, wherein the nose has a left side and a right side relative to the nose tip, and wherein the angle determining means determines a regression line on at least one of the left side and the right side and determines the yaw angle in accordance with the regression line.

28. A method of determining a yaw angle of a detected object, the method comprising:

projecting light pulses onto the detected object;

collecting light pulses reflected off the detected object and detecting a shape of the detected object in accordance with the light pulses; and

determining the yaw angle from the shape detected by the collecting means.

29. The method of claim 28, wherein the detected object comprises a nose having a nose tip, and wherein said step of determining comprises determining the yaw angle from a portion of the shape which is adjacent to the nose tip.

30. The method of claim 29, wherein the nose has a left side and a right side relative to the nose tip, and wherein said step of determining comprises determining a regression line on at least one of the left side and the right side and determining the yaw angle in accordance with the regression line.

31. A system for determining whether a vehicle is following a center line, the vehicle having a nose and a wheel, the system comprising:

a storage device for storing (i) coordinates representing a path of the center line and (ii) a distance between the nose and the wheel;

a detecting device for detecting (i) a position of the nose and (ii) a yaw angle of the vehicle; and

a calculating device for calculating (i) a position of the wheel, from the position of the nose, the yaw angle detected by the detecting device and the distance stored in the storage device, and (ii) an offset of the wheel from the center line, from the coordinates stored in the storage device and the position of the wheel.

32. A method of determining whether a vehicle is following a center line, the vehicle having a nose and a wheel, the method comprising:

storing coordinates representing a path of the center line;

storing a distance between the nose and the wheel;

detecting a position of the nose;

detecting a yaw angle of the vehicle;

calculating a position of the wheel, from the position of the nose, the yaw angle detected by the detecting device and the distance stored in the storage device; and

calculating an offset of the wheel from the center line, from the coordinates stored in the storage device and the position of the wheel.