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

• US 20090143969A1
• Filed: 12/01/2008
• Published: 06/04/2009
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: Saab Inc (Saab AB)
• Original Assignee: Sensis Corp (Saab AB)
• Inventors: LEVY, Benjamin S.
• Granted Patent: US 8,145,415 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 using airport surveillance data to output a location of a delay and an amount of time a vehicle is subjected to the delay during a movement of the vehicle between two locations, the delays being observed in the surveillance data as a knot of several data points. A first method is used to identify proposed knots based on distances between individual data points within the data. A second method is used to identify proposed knots based on the speed of the vehicle. Another method can be used to separate proposed knots have been incorrectly joined together. This method performs the separation by arranging the data points into a two-dimensional grid to form clusters of grid cells having data points. The location of the individual cells is then analyzed to determine whether clusters should be separated. Each of the remaining clusters defines a hold where the vehicle is delayed.

Claims

1. A method using airport surveillance data to output 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 vector (v) including a plurality of elements by performing the following steps for each data point (i) in the time ordered sequence, each of the elements corresponding to a respective one of the data points from the time ordered sequence, the steps comprising;

calculating a radial distance (r_i,j) between the (x) and (y) coordinates of the data point (i) and the (x) and (y) coordinates of each of the remaining data points (j), each radial distance (r_i,j) being equal to [(x_i−

x_j)²+(y_i−

y_j)²]^1/2; and

recording one of a zero (0) entry and a number (N) entry as one element in the vector (v) corresponding to the data point (i), the zero (0) entry if there are no radial distances (r_i,j) that are less than a predetermined distance (r_min), the number (N) entry being the number of radial distances (r_i,j) that are equal to or less than the predetermined distance (r_min);

replacing all of the number (N) entries in the vector (v) that have a value greater than a predetermined value (K) with a one (1) entry;

replacing all of the number (N) entries in the vector (v) that have a value equal to or less than the predetermined value (K) with a zero (0) entry;

replacing each zero (0) entry in the vector (v) with a one (1) entry if the zero (0) entry is a part of a sequence of consecutive zero (0) entries, the sequence of consecutive zero entries being less than a predetermined value (S);

defining a starting index and a stopping index within the vector (v) for each sequence of consecutive one (1) entries, each of the sequences of consecutive one (1) entries defining a proposed knot (ki);

performing the following steps for each proposed knot (ki);

finding a mean location (E(x), E(y)) for the proposed knot (ki), the mean location being the average of the (x) and (y) coordinates of the data points in the sequence of consecutive (1) entries in the proposed knot (ki);

calculating a radial distance (kr) between the mean location (E(x), E(y)) of the proposed knot and the (x) and (y) coordinates of each respective data point corresponding to the sequence of consecutive (1) entries in the proposed knot (ki);

each radial distance (kr) being equal to [(x_i−

E(x))²+(y_i−

E(y))²]^1/2;

computing a scale factor (m), where m=log_e (length (r))/OSR; and

dropping any data points from being associated with the proposed knot if its respective radial distance (kr) exceeds an average of all the radial distances (kr_i,j) for a given proposed knot+the scale factor (m)* a standard deviation of all the radial distances (kr) associated with the proposed knot;

eliminating any proposed knots that have less than a predetermined number (d) of data points remaining;

identifying the data points associated with any remaining proposed knot as being associated with the respective proposed knot; and

saving the data points identified 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 those data points as being associated with one of the proposed knots.

2. The method according to claim 1, wherein the predetermined distance (r_min) is between 15 feet and 30 feet.

3. The method according to claim 1, wherein the predetermined distance (r_min) is 30 feet.

4. The method according to claim 1, wherein the predetermined value (K) is between 5 and 15.

5. The method according to claim 1, wherein the predetermined value (K) is 10.

6. The method according to claim 1, wherein the predetermined value (S) is between 2 and 10.

7. The method according to claim 1, wherein the predetermined value (S) is 5.

8. The method according to claim 1, wherein the predetermined variable (OSR) is between 5 and 10.

9. The method according to claim 1, wherein the predetermined variable (OSR) is 7.

10. The method according to claim 1, wherein the predetermined number (d) is between 2 and 15.

11. The method according to claim 1, wherein the predetermined number (d) is 5.

12. The method according to claim 1, wherein the vehicle is an aircraft.

13. A method using airport surveillance data to output 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 vector (sv) including a plurality of elements, each of the elements corresponding to a respective one of the data points from the time ordered sequence, each of the elements being a ground speed associated with the respective data point;

replacing all of the ground speed entries in the vector (sv) with one of a zero (0) entry and a one (1) entry, the one (1) entry if the ground speed entry is less than the predetermined minimum ground speed (GS_min) or if Vg is a NaN, the zero (0) entry if the ground speed is equal to or greater than the predetermined minimum ground speed (GS_min) and the ground speed value is not a NaN;

defining a starting index and a stopping index within the vector (sv) for each sequence of consecutive one (1) entries, each of the sequences of consecutive one (1) entries defining a proposed knot;

defining a time duration of each of the proposed knots using the time stamps of the respective data points;

eliminating any proposed knot having a duration of less than a predetermined time duration (T);

performing the following steps for each remaining proposed knot (ki);

finding a mean location (E(x), E(y)) for the proposed knot (pi), the mean location being the average of the (x) and (y) coordinates of data points in the sequence of consecutive (1) entries in the proposed knot (pi);

calculating a radial distance (pr) between the mean location (E(x), E(y)) of the proposed knot (pi) and the (x) and (y) coordinates of each respective data point corresponding to the sequence of consecutive (1) entries in the proposed knot (pi), each radial distance (pr) being equal to [(x_i−

E(x))²+(y_i−

E(y))²]^1/2;

computing a scale factor (m) where m=log_e (length (r))/OSR; and

keeping data points associated with the proposed knot if r is less than the larger of the two values from the inequality r<

max (maxDistance, m•

std(r));

merging any of the proposed knots that overlap;

identifying the data points associated with any remaining proposed knot as being associated with the respective proposed knot; and

saving the data points identified 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 those data points as being associated with one of the proposed knots.

14. The method according to claim 13, wherein the predetermined minimum ground speed (GS_min) is between 1 and 5 knots.

15. The method according to claim 13, wherein the predetermined minimum ground speed (GS_min) is between 1 and 3 knots

16. The method according to claim 13, wherein the predetermined minimum ground speed (GS_min) is 1.9 knots

17. The method according to claim 13, wherein the predetermined time duration (T) is between 10 seconds and 120 seconds.

18. The method according to claim 13, wherein the predetermined time duration (T) is 30 seconds.

19. The method according to claim 13, wherein the predetermined variable (OSR) is between 5 and 10.

20. The method according to claim 13, wherein the predetermined variable (OSR) is 7.

21. The method according to claim 13, wherein the vehicle is an aircraft.

22. A method using airport surveillance data to output 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 data points associated with a proposed knot identified by a first method;

obtaining data points associated with a proposed knot identified by a second method;

outputting a value of zero (0) if the first method and the second method do not identify any proposed knots;

keeping proposed knots when the first method outputs a proposed knot including data points that are not identified as part of a proposed knot outputted by the second method;

keeping proposed knots when the second method outputs a proposed knot including data points that are not identified as part of a proposed knot outputted by the first method;

merging data points into a new proposed knot such that the resultant list of data points associated with the new proposed knot is a superset of the list of individual data points from both proposed knots when the first method identifies a proposed knot with individual locations that overlap, supersede, or are subsumed by the individual locations of one of the proposed knots identified by the second method; and

merging data points into a new proposed knot when the resultant list of data points associated with the new proposed knot is a superset of the list of individual locations from both proposed knots when the second method identifies a proposed knot with individual data points that overlap, supersede, or are subsumed by the individual locations of one of the proposed knots identified by the first method;

identifying the data points associated with any remaining proposed knot as being associated with the respective proposed knot; and

saving the data points identified 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 those data points as being associated with one of the proposed knots.

23. A method using airport surveillance data to output 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 data points associated with at least one proposed knot;

converting the (x) and (y) coordinates for each data point associated with each of the remaining proposed knots into a row/column address, each row/column address falling into one of a plurality of two-dimensional cells arranged in a two-dimensional grid, the grid having a predetermined spacing (gs), a cell having at least one of the data points falling therein being an active cell;

determining recursively a list of clusters of active cells that are comprised of contiguous active cells, the active cells being separated by a distance of less than or equal to √

{square root over (2)} times the distance from a center of an active cell to a center of another active cell;

grouping any of the clusters whose distances are not further than √

{square root over (2)} times (*) the distance from the center of an active cell to the center of another active cell

identifying the data points associated with their respective clusters, those data points being representative of a hold where the vehicle is delayed; and

saving the data points representing the identified 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 those data points as being associated with the hold.

24. The method according to claim 23, wherein the predetermined spacing (sg) is between 5 and 50 feet.

25. The method according to claim 23, wherein the predetermined spacing (sg) is 15 feet.