AUTOMATIC DETERMINATION OF AIRCRAFT HOLDING LOCATIONS AND HOLDING DURATIONS FROM AIRCRAFT SURVEILLANCE DATA

• US 20120323475A1
• Filed: 08/29/2012
• Published: 12/20/2012
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: Saab Sensis Corp. (Saab AB)
• Original Assignee: Saab Sensis Corp. (Saab AB)
• Inventors: Levy, Benjamin S., Roman, Stephen T., Knickerboker, Collen J.
• Granted Patent: US 8,401,776 B2
• Time in Patent Office: Days
• US Class Current: 701/120
• CPC Class Codes: G08G 5/06 for control when on the ground

Abstract

A method of using airport surveillance data to determine a location of a delay and an amount of time a vehicle is subjected to the delay during a movement of the vehicle between locations including obtaining a time-ordered sequence of data points representing the movement of the vehicle, creating a speed vector (sv) for each data point, replacing ground speed elements in the speed vector (sv) with a one when the ground speed element is less than a speed threshold, performing a spatial density test on each data point in a sequence of consecutive one entries, defining a starting and stopping index for a consecutive sequence of data points as a preliminary hold, determining whether to merge adjacent preliminary holds, determining a time duration of each preliminary hold and eliminating any preliminary hold having a time duration less than a predetermined time duration and outputting the results.

Claims

1. A method of using airport surveillance data to determine a location of a delay and an amount of time a vehicle is subjected to the delay during a movement of the vehicle between a first location and a second location, the method comprising:

obtaining a time-ordered sequence of data points representing the movement of the vehicle, each data point including an (x) position coordinate and a (y) position coordinate, at a particular time represented by a time stamp;

creating a speed vector (sv) including a plurality of elements, each of the elements corresponding to one of the data points from the time ordered sequence, wherein one of the elements is a ground speed element associated with the data point;

determining the ground speed elements in the speed vector (sv) that are less than a predetermined ground speed threshold or are a NaN;

performing a spatial density test on each data point in a sequence of data points having ground speed elements that are less than the predetermined ground speed threshold, wherein the data point passes the spatial density test when a determined number of the data points within a predetermined range of a selected data point is greater than or equal to a predetermined threshold value;

defining a starting index and a stopping index within the vector (sv) for each consecutive sequence of data points as a preliminary hold where each data point in the sequence has a ground speed element that is less than the predetermined speed threshold and passes the spatial density test;

determining whether to merge each identified preliminary hold with an adjacent identified preliminary hold into a single preliminary hold;

determining a time duration of each identified preliminary hold and eliminating any identified preliminary hold having a determined time duration of less than a predetermined time duration; and

outputting and saving the identified preliminary holds onto a computer readable medium for at least one of review by an individual, production of a graphical display on a computer terminal, and production of a presentation document identifying the identified preliminary holds.

2. The method of claim 1, wherein the spatial test comprises:

selecting a predetermined number of data points that are closest to each data point in the sequence of data points identified as a preliminary hold;

determining a number of the selected data points that fall within a predetermined range to each data point in the sequence of data points identified as a preliminary hold; and

comparing the determined number of data points that fall within the predetermined range to each data point to a predetermined threshold value, wherein the data point passes the spatial test when the determined number of data points within the predetermined distance is greater than or equal to the predetermined threshold value.

3. The method of claim 1, wherein determining whether to merge adjacent preliminary holds comprises:

determining a mean XY value for each of a first identified preliminary hold and a second identified preliminary hold, where the second identified preliminary hold is adjacent to the first identified preliminary hold;

determining a radial distance between the determined mean XY values for the first identified preliminary hold and the determined mean XY value for the second identified preliminary hold;

determining a time difference between an end of the first identified preliminary hold and a start of the second identified preliminary hold;

comparing the determined radial distance to a predetermined radial distance threshold value;

comparing the determined time difference to a predetermined time difference threshold value; and

merging the first identified preliminary hold and the second identified preliminary hold into a single preliminary hold when the determined radial distance is less than the predetermined threshold value and the determined time difference is less than the predetermined threshold value.

4. The method of claim 3, further comprising performing a distance check when at least one of the determined radial distance is not less than the predetermined radial distance threshold value and the determined time difference is not less than the predetermined time difference threshold value, to determine whether to merge adjacent preliminary holds, the distance check comprising:

determining whether the determined radial distance is less than two times the predetermined radial distance threshold value, and

when the determined radial distance is less than two times the predetermined radial distance threshold value;

determining a central mean XY value for the first identified preliminary hold and the second identified preliminary hold using the determined mean XY values for the first identified preliminary hold and the second identified preliminary hold;

determining a radial distance from the determined central mean XY value to each point after the first identified preliminary hold and before the second identified preliminary hold;

determining whether a number of points within a predetermined distance of the determined central mean is greater than a predetermined threshold value; and

merging the first identified preliminary hold and a second identified preliminary hold into a single preliminary hold when the number of points within the predetermined distance of the determined central mean is greater than a predetermined value.

5. The method of claim 4, further comprising determining whether to merge the single preliminary hold with another adjacent preliminary hold and when the another adjacent preliminary hold merges with the single preliminary hold, continuing to determine whether to merge other adjacent preliminary holds with the single preliminary hold until at least one of the following conditions are met (i) the other adjacent preliminary hold does not merge with the single preliminary hold and (ii) there are no more adjacent preliminary holds to determine whether to merge.

6. The method of claim 1, wherein the predetermined ground speed threshold is not more than 5 knots.

7. The method of claim 6, wherein the predetermined ground speed threshold is 3.5 knots or less.

8. The method of claim 1, wherein the predetermined time duration for maintaining an identified preliminary hold is at least 5 seconds.

9. The method of claim 8, wherein the predetermined time duration for maintaining an identified preliminary hold is 10 seconds or more.

10. The method of claim 1, wherein the predetermined threshold value in the spatial density test is at least 30 data points falling within the predetermined range.

11. The method of claim 10, wherein the predetermined threshold value in the spatial density test is at least 40 data points falling within the predetermined range.

12. The method of claim 2, wherein the selected predetermined number of data points is not more than 300 data points.

13. The method of claim 12, wherein the selected predetermined number of data points is not more than 100 data points.

14. The method of claim 3, wherein the predetermined radial distance threshold is not more than 20 meters.

15. The method of claim 14, wherein the predetermined radial distance threshold is 10 meters or less.

16. The method of claim 3, wherein the predetermined time difference threshold value to merge adjacent preliminary holds is less than 20 seconds.

17. The method of claim 16, wherein the predetermined time difference threshold value to merge adjacent preliminary holds is 10 seconds or less.

18. The method of claim 4, wherein the predetermined threshold value is at least 80%.

20. The method of claim 5, further comprising determining whether to merge two adjacent preliminary holds later in time and where the two adjacent preliminary holds merge into another single preliminary hold, continuing to determine whether to merge adjacent preliminary holds with the another single preliminary hold until at least one of the following conditions are met (i) the another adjacent holds does not merge with the another single preliminary hold and (ii) there are no more preliminary holds to merge.

19. A method of using airport surveillance data to determine a location of a delay and an amount of time a vehicle is subjected to the delay during a movement of the vehicle between a first location and a second location, the method comprising:

obtaining a time-ordered sequence of data points representing the movement of the vehicle, each data point including an (x) position coordinate and a (y) position coordinate, at a particular time represented by a time stamp;

creating a speed vector (sv) including a plurality of elements, each of the elements corresponding to one of the data points from the time ordered sequence, wherein one of the elements is a ground speed element associated with the data point;

replacing the ground speed elements in the speed vector (sv) with one of a zero (0) entry and a one (1) entry, the one (1) entry designating that the ground speed element is less than the predetermined ground speed threshold or is a NaN, and the zero (0) entry designating that the ground speed is equal to or greater than the predetermined ground speed threshold and the ground speed value is not a NaN;

performing a spatial density test on each data point in a sequence of data points having consecutive one (1) entries for the ground speed element, wherein the data point passes the spatial density test when a determined number of the data points within a predetermined range of a selected data point is greater than or equal to a predetermined threshold value;

defining a starting index and a stopping index within the vector (sv) for each consecutive sequence of data points as a preliminary hold where each data point in the sequence has a one (1) entry for the ground speed element and passes the spatial density test;

determining whether to merge each identified preliminary hold with an adjacent identified preliminary hold into a single preliminary hold;

determining a time duration of each identified preliminary hold and eliminating any identified preliminary hold having a determined time duration of less than a predetermined time duration; and

outputting and saving the identified preliminary holds onto a computer readable medium for at least one of review by an individual, production of a graphical display on a computer terminal, and production of a presentation document identifying the identified preliminary holds.