Aircraft docking system and method with automatic checking of apron and detection of fog or snow

• US 6,563,432 B1
• Filed: 01/12/2001
• Issued: 05/13/2003
• Est. Priority Date: 01/12/2001
• Status: Expired due to Term

• Current Assignee: ADB Safegate Sweden AB (ADB Safegate BVBA)
• Original Assignee: Safegate International AB (ADB Safegate BVBA)
• Inventors: Millgård, Lars
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): Nguyen, Tai T.
• Application Number:
  US09/758,416
• Time in Patent Office: 851 Days
• Field of Search: 340/961, 340/968, 340/958, 340/903, 340/942, 340/602, 340/601, 244/114.R
• US Class Current: 340/961
• CPC Class Codes: B64F 1/002 Taxiing aids
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/933 of aircraft or spacecraft
• CPC Class Codes: G01S 17/95 for meteorological use
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G08G 5/0026 located on the ground
• CPC Class Codes: G08G 5/0082 for monitoring traffic from a ground station radar or analogous systems specially adapted for traffic control G01S13/91
• CPC Class Codes: G08G 5/06 for control when on the ground
• CPC Class Codes: G08G 5/065 Navigation or guidance aids, e.g. for taxiing or rolling
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A system for detecting, identifying and docking aircraft using laser pulses to obtain a profile of an object in the distance initially scans the area in front of the gate until it locates and identifies an object. Once the identity of the object is known, the system tracks the object. The system also monitors an area of the apron near the object to detect obstacles such as ground service vehicles. The system also analyzes the laser pulses to determine whether they are reflected from a solid object or from fog or other condensation or precipitation to avoid misidentifying condensation or precipitation as a solid object.

Claims

1. A method for identifying a detected object and determining whether an obstacle is present in an area near the object, the method comprising:

(a) projecting a first set of light pulses onto the object and a second set of light pulses into the area to generate reflected pulses;

(b) receiving the reflected pulses in a detector;

(c) identifying the object based on the reflected pulses from the first set of light pulses; and

(d) determining whether the obstacle is present in the area based on the reflected pulses from the second set of light pulses.

2. The method of claim 1, wherein, during step (a), the first and second sets of light pulses are projected in alternation.

3. The method of claim 1, wherein:

the second set of light pulses is projected into the area a plurality of times to produce at least first and second sets of reflected pulses from the area; and

if the obstacle is detected in the first set of reflected pulses, the second set of reflected pulses is used to determine whether the obstacle is moving.

4. The method of claim 3, wherein, if the obstacle is determined not to be moving, the second set of light pulses is projected into the area again to produce at least a third set of reflected pulses, and step (d) comprises determining from the third set of reflected pulses whether the obstacle is still present.

5. The method of claim 1, wherein the second set of light pulses comprises light pulses directed at a plurality of vertical angles.

6. The method of claim 1, wherein, during step (d), the reflected pulses reflected from below a certain level above ground are ignored.

7. The method of claim 1, further comprising, after the object is identified:

(e) tracking the object as the object moves toward a gate; and

continuing steps (a), (b) and (d) during step (e) to detect the obstacle as the object moves toward the gate.

8. The method of claim 1, wherein:

the object is an aircraft; and

the area is in an apron of the aircraft.

9. The method of claim 8, wherein the obstacle to be detected is an obstacle which would cause damage to the aircraft if the aircraft collided with the obstacle.

10. The method of claim 9, wherein the obstacle to be detected is a ground service vehicle for servicing the aircraft.

11. A method for detecting an object in an area in which condensation or precipitation may be present, the method comprising:

(a) projecting light pulses into the area to generate reflected pulses;

(b) receiving the reflected pulses in a detector;

(c) determining whether the reflected pulses result from the condensation or precipitation; and

(d) if it is determined in step (c) that the reflected pulses do not result from the condensation or precipitation, detecting the object based on the reflected pulses.

12. The method of claim 11, wherein, if it is determined in step (c) that the reflected pulses result from the condensation or precipitation, steps (a) and (b) are continued until the object is detected through the condensation or precipitation.

13. The method of claim 12, wherein:

the object is an aircraft;

the method is implemented in an aircraft docking system which comprises an aircraft docking display; and

if it is determined in step (c) that the reflected pulses result from the condensation or precipitation, the aircraft docking display is controlled to indicate downgraded performance of the aircraft docking system to a pilot of the aircraft.

14. The method of claim 11, wherein step (c) comprises:

(i) calculating a quantity representing a spatial distribution of the reflected pulses; and

(ii) using the quantity calculated in step (c)(i) to determine whether the reflected pulses result from the condensation or precipitation.

15. The method of claim 14, wherein the quantity is a measure of randomness of spatial positions of the reflected pulses.

16. The method of claim 15, wherein step (c)(i) comprises:

(A) calculating a difference between distance values for adjacent ones of the reflected pulses;

(B) rejecting those reflected pulses for which the difference calculated in step (c)(i)(A) is lower than a threshold;

(C) rejecting any three adjacent ones of the reflected pulses which have a distance change with a same sign; and

(D) calculating a quotient of a number of the reflected pulses remaining after steps (c)(i)(A) through (c)(i)(C) to a total number of the reflected pulses.

17. A system for identifying a detected object and determining whether an obstacle is present in an area near the object, the system comprising:

a light source for projecting a first set of light pulses onto the object and a second set of light pulses into the area to generate reflected pulses;

a detector for receiving the reflected pulses; and

a computing device for identifying the object based on the reflected pulses from the first set of light pulses and for determining whether the obstacle is present in the area based on the reflected pulses from the second set of light pulses.

18. The system of claim 17, wherein the light source projects the first and second sets of light pulses in alternation.

19. The system of claim 17, wherein:

the second set of light pulses is projected into the area a plurality of times to produce at least first and second sets of reflected pulses from the area; and

if the obstacle is detected in the first set of reflected pulses, the second set of reflected pulses is used to determine whether the obstacle is moving.

20. The system of claim 19, wherein, if the obstacle is determined not to be moving, the second set of light pulses is projected into the area again to produce at least a third set of reflected pulses, and the computing device determines from the third set of reflected pulses whether the obstacle is still present.

21. The system of claim 17, wherein the second set of light pulses comprises light pulses directed by the light source at a plurality of vertical angles.

22. The system of claim 17, wherein the computing device ignores the reflected pulses reflected from below a certain level above ground in determining whether the obstacle is present.

23. The system of claim 17, wherein, after the object is identified, the computing device tracks the object as the object moves toward a gate, and the light source, detector and computing device operate while the object moves toward the gate to detect the obstacle as the object moves toward the gate.

24. A system for detecting an object in an area in which condensation or precipitation may be present, the system comprising:

a light source for projecting light pulses into the area to generate reflected pulses;

a detector for receiving the reflected pulses; and

a computing device for determining whether the reflected pulses result from the condensation or precipitation and, if the reflected pulses do not result from the condensation or precipitation, detecting the object based on the reflected pulses.

25. The system of claim 24, wherein, if the computing device determines that the reflected pulses result from the condensation or precipitation, the light source and detector continue to operate until the object is detected through the condensation or precipitation.

26. The system of claim 25, wherein:

the system is implemented in an aircraft docking system which comprises an aircraft docking display; and

if the computing device determines that the reflected pulses result from the condensation or precipitation, the computing device controls the aircraft docking display to indicate downgraded performance of the aircraft docking system.

27. The system of claim 24, wherein the computing device determines whether the reflected pulses result from the condensation or precipitation by:

(i) calculating a quantity representing a spatial distribution of the reflected pulses; and

(ii) using the quantity to determine whether the reflected pulses result from the condensation or precipitation.

28. The system of claim 27, wherein the quantity is a measure of randomness of spatial positions of the reflected pulses.

29. The system of claim 28, wherein the computing device calculates the quantity by:

(A) calculating a difference between distance values for adjacent ones of the reflected pulses;

(B) rejecting those reflected pulses for which the difference calculated in step (A) is lower than a threshold;

(C) rejecting any three adjacent ones of the reflected pulses which have a distance change with a same sign; and

(D) calculating a quotient of a number of the reflected pulses remaining after steps (A) through (C) to a total number of the reflected pulses.