METHOD AND SYSTEM FOR ESTIMATING AIRCRFT COURSE

• US 20150066363A1
• Filed: 07/14/2014
• Published: 03/05/2015
• Est. Priority Date: 08/30/2013
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: D'Alto, Luis P., La Civita, Marco
• Granted Patent: US 9,366,538 B2
• Time in Patent Office: Days
• US Class Current: 701/518
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G05D 1/0202 specially adapted to aircraft

Abstract

A method of estimating a course of an aircraft includes: receiving a time series of location data indicating a plurality of locations along a route take by an aircraft; defining a trajectory function for representing a path of the aircraft; fitting the trajectory function to at least a portion of the time series; defining a position that identifies the location of the aircraft along the route; projecting the defined position onto the trajectory function; and estimating a course of the aircraft as being a tangent of the trajectory function at the projected defined position.

Claims

1. A method of estimating a course of an aircraft comprising:

receiving a time series of location data indicating a plurality of locations along a route taken by an aircraft;

defining a trajectory function for representing a path of the aircraft;

fitting the trajectory function to at least a portion of the time series;

defining a position that identifies the location of the aircraft along the route;

projecting the defined position onto the trajectory function; and

estimating a course of the aircraft as being a tangent of the trajectory function at the projected defined position.

2. The method of claim 1, further comprising:

defining one or more further trajectory functions, each for representing the path of the aircraft; and

fitting the one or more further trajectory functions to at least a further portion of the time series.

3. The method of claim 1 wherein the defining the trajectory function representing the path of the aircraft comprises defining the trajectory function having parameters which, when determined, define the path of the aircraft between two locations on an Earth model.

4. The method of claim 1, wherein fitting the trajectory function to at least the portion of the time series comprises:

defining an error criterion representing an error in how well the trajectory function fits the at least the portion of the time series; and

determining parameters of the trajectory function which minimize the error criterion.

5. The method of claim 1, wherein defining the trajectory function comprises:

defining a plurality of path functions, each of which define a differently shaped path;

selecting from the plurality of path functions a selected path function to fit to the at least the portion of the time series; and

using the selected path function as the trajectory function.

6. The method of claim 5, wherein selecting from the plurality of path functions the selected path function to fit to the at least the portion of the time series comprises:

defining an error criterion representing an error in how well the path function fits the at least the portion of the time series;

calculating the error criterion for each of the plurality of path functions; and

selecting the path function that best fits a portion of trajectory data.

7. The method of claim 5, wherein selecting from the plurality of path functions the selected path function to fit to the at least the portion of the time series comprises:

calculating from the at least the portion of the time series, tangent against time data representing a plurality of tangents at locations along the route, each tangent being associated with a time at which the aircraft was at the respective location;

fitting a straight line to the tangent against time data; and

selecting the path function based on a gradient of the straight line.

8. The method of claim 5 wherein the plurality of path functions comprise:

one path function that represents a straight track; and

another path function that represents an arc-shaped track.

9. The method of claim 1, wherein estimating the course of the aircraft as being the trajectory function at the projected defined position comprises:

calculating the tangent to the trajectory function at the projected defined position; and

estimating a current course of the aircraft as being the calculated tangent.

10. The method of claim 1 wherein projecting the defined position onto the trajectory function comprises calculating a point on the path represented by the trajectory function closest to a current position of the aircraft.

11. A system for estimating a course of an aircraft, the system comprising a processor, a memory, and a display, wherein said processor is configured to:

receive a time series of location data indicating a plurality of locations along a route taken by the aircraft;

define a trajectory function for representing a path of the aircraft;

fit the trajectory function to at least a portion of the time series;

define a position that identifies a location of the aircraft along the route;

project the defined position onto the trajectory function; and

estimate a course of the aircraft as being a tangent of the trajectory function at the projected defined position.

12. The system of claim 11 wherein said processor is further configured to:

define one or more further trajectory functions, each for representing the path of the aircraft; and

fit the one or more further trajectory functions to at least a further portion of the time series.

13. The system of claim 11, wherein fitting the trajectory function to at least the portion of the time series comprises:

defining an error criterion representing an error in how well the trajectory function fits the at least the portion of the time series; and

determining parameters of the trajectory function which minimize the error criterion.

14. The system of claim 11, wherein defining the trajectory function comprises:

defining a plurality of path functions, each of which define a differently shaped path;

selecting from the plurality of path functions a selected path function to fit to the at least the portion of the time series; and

using the selected path function as the trajectory function.

15. The system of claim 14, wherein selecting from the plurality of path functions the selected path function to fit to the at least the portion of the time series comprises:

defining an error criterion representing an error in how well the path function fits the at least the portion of the time series;

calculating the error criterion for each of the plurality of path functions; and

selecting the path function that best fits a portion of trajectory data.

16. The system of claim 14, wherein selecting from the plurality of path functions the selected path function to fit to the at least the portion of the time series comprises:

calculating from the at least the portion of the time series, tangent against time data representing a plurality of tangents at locations along the route, each tangent being associated with a time at which the aircraft was at the respective location;

fitting a straight line to the tangent against time data; and

selecting the path function based on a gradient of the straight line.

17. The system of claim 14, wherein the plurality of path functions comprise:

one path function that represents a straight track; and

another path function that represents an arc-shaped track.

18. The system of claim 11, wherein estimating the course from the trajectory function using the projected defined position comprises:

calculating the tangent to the trajectory function at the projected defined position; and

estimating a current course of the aircraft as being the calculated tangent.

19. The system of claim 11, wherein projecting the defined position onto the trajectory function comprises calculating a point on the path represented by the trajectory function closest to a current position of the aircraft.

20. The system of claim 11 wherein said processor is further configured to display the estimated course on said display.