Supporting flight operations of an aircraft in an airspace system

1. An apparatus for supporting flight operations of an aircraft in an airspace system, the apparatus comprising:

a memory configured to store computer-readable program code; and

processing circuitry configured to access the memory, and execute the computer-readable program code to cause the apparatus to at least:

access a flight plan that describes a proposed flight of the aircraft, the flight plan indicating clearances that describe a planned route the aircraft is authorized by an air navigation service provider (ANSP) to travel through the airspace system;

apply the clearances to an airborne navigation database to map the clearances to a sequence of procedural legs of procedures defined by the ANSP, the sequence of procedural legs including a sequence of position fixes, and indicating leg types each leg type of which is described by a type of flight path and a type of termination of the type of flight path;

determine a ground track and vertical guidance for the aircraft from the sequence of procedural legs including the sequence of position fixes and the leg types, subject to rules and constraints of the clearances and the procedures;

generate a three-dimensional (3D) trajectory for the aircraft that follows the planned route, from the ground track and the vertical guidance; and

output the 3D trajectory for use in at least one of guidance, navigation or control of the aircraft.

2. The apparatus of claim 1 , wherein the apparatus caused to determine the ground track includes the apparatus caused to:

generate a sequence of simple procedural legs in which a procedural leg with a leg type including one or more turns is expanded into a sequence of procedural sub-legs with leg types excluding turns; and

determine the ground track from the sequence of simple procedural legs.

3. The apparatus of claim 2 , wherein the apparatus caused to generate the sequence of simple procedural legs includes the apparatus caused to:

access state data that describes a start position, speed and heading of the aircraft at a position fix of the procedural leg with the leg type including the one or more turns; and

expand the procedural leg into the sequence of procedural sub-legs including a respective sequence of position fixes determined from the start position, speed and heading.

4. The apparatus of claim 2 , wherein the apparatus caused to determine the ground track includes the apparatus caused to:

identify start positions of the aircraft at position fixes in the sequence of simple procedural legs, and one or more target altitudes, speeds and vertical speeds of the aircraft; and

apply the start positions, and the one or more target altitudes, speeds and vertical speeds, to a kinematic model of the aircraft to determine the ground track.

5. The apparatus of claim 4 , wherein the ground track as determined is expressed as a path composed of the start positions interconnected by one or more of geodesics or arcs on a reference ellipsoid.

6. The apparatus of claim 1 , wherein the apparatus caused to determine the vertical guidance includes the apparatus caused to:

determine one or more notional altitudes, speeds and vertical speeds of the aircraft over the ground track; and

apply the one or more notional altitudes, speeds and vertical speeds to a kinematic model of the aircraft to determine one or more target altitudes, speeds and vertical speeds from which the vertical guidance is determined.

7. The apparatus of claim 6 , wherein the apparatus caused to determine the vertical guidance includes the apparatus further caused to:

identify start positions, speed and heading of the aircraft at position fixes in the sequence of procedural legs; and

apply the start positions, speed and heading, and the one or more target altitudes, speeds and vertical speeds, to the kinematic model to determine the vertical guidance as reachable altitude and speed along the ground track.

8. A method of supporting flight operations of an aircraft in an airspace system, the method comprising:

accessing a flight plan that describes a proposed flight of the aircraft, the flight plan indicating clearances that describe a planned route the aircraft is authorized by an air navigation service provider (ANSP) to travel through the airspace system;

applying the clearances to an airborne navigation database to map the clearances to a sequence of procedural legs of procedures defined by the ANSP, the sequence of procedural legs including a sequence of position fixes, and indicating leg types each leg type of which is described by a type of flight path and a type of termination of the type of flight path;

determining a ground track and vertical guidance for the aircraft from the sequence of procedural legs including the sequence of position fixes and the leg types, subject to rules and constraints of the clearances and the procedures;

generating a three-dimensional (3D) trajectory for the aircraft that follows the planned route, from the ground track and the vertical guidance; and

outputting the 3D trajectory for use in at least one of guidance, navigation or control of the aircraft.

9. The method of claim 8 , wherein determining the ground track comprises:

generating a sequence of simple procedural legs in which a procedural leg with a leg type including one or more turns is expanded into a sequence of procedural sub-legs with leg types excluding turns; and

determining the ground track from the sequence of simple procedural legs.

10. The method of claim 9 , wherein generating the sequence of simple procedural legs comprises:

accessing state data that describes a start position, speed and heading of the aircraft at a position fix of the procedural leg with the leg type including the one or more turns; and

expanding the procedural leg into the sequence of procedural sub-legs including a respective sequence of position fixes determined from the start position, speed and heading.

11. The method of claim 9 , wherein determining the ground track comprises:

identifying start positions of the aircraft at position fixes in the sequence of simple procedural legs, and one or more target altitudes, speeds and vertical speeds of the aircraft; and

applying the start positions, and the one or more target altitudes, speeds and vertical speeds, to a kinematic model of the aircraft to determine the ground track.

12. The method of claim 11 , wherein the ground track as determined is expressed as a path composed of the start positions interconnected by one or more of geodesics or arcs on a reference ellipsoid.

13. The method of claim 8 , wherein determining the vertical guidance comprises:

determining one or more notional altitudes, speeds and vertical speeds of the aircraft over the ground track; and

applying the one or more notional altitudes, speeds and vertical speeds to a kinematic model of the aircraft to determine one or more target altitudes, speeds and vertical speeds from which the vertical guidance is determined.

14. The method of claim 13 , wherein determining the vertical guidance further comprises:

identifying start positions, speed and heading of the aircraft at position fixes in the sequence of procedural legs; and

applying the start positions, speed and heading, and the one or more target altitudes, speeds and vertical speeds, to the kinematic model to determine the vertical guidance as reachable altitude and speed along the ground track.

15. A computer-readable storage medium for supporting flight operations of an aircraft in an airspace system, the computer-readable storage medium being non-transitory and having computer-readable program code stored therein that, in response to execution by processing circuitry, causes an apparatus to at least:

access a flight plan that describes a proposed flight of the aircraft, the flight plan indicating clearances that describe a planned route the aircraft is authorized by an air navigation service provider (ANSP) to travel through the airspace system;

apply the clearances to an airborne navigation database to map the clearances to a sequence of procedural legs of procedures defined by the ANSP, the sequence of procedural legs including a sequence of position fixes, and indicating leg types each leg type of which is described by a type of flight path and a type of termination of the type of flight path;

determine a ground track and vertical guidance for the aircraft from the sequence of procedural legs including the sequence of position fixes and the leg types, subject to rules and constraints of the clearances and the procedures;

generate a three-dimensional (3D) trajectory for the aircraft that follows the planned route, from the ground track and the vertical guidance; and

output the 3D trajectory for use in at least one of guidance, navigation or control of the aircraft.

16. The computer-readable storage medium of claim 15 , wherein the apparatus caused to determine the ground track includes the apparatus caused to:

generate a sequence of simple procedural legs in which a procedural leg with a leg type including one or more turns is expanded into a sequence of procedural sub-legs with leg types excluding turns; and

determine the ground track from the sequence of simple procedural legs.

17. The computer-readable storage medium of claim 16 , wherein the apparatus caused to generate the sequence of simple procedural legs includes the apparatus caused to:

access state data that describes a start position, speed and heading of the aircraft at a position fix of the procedural leg with the leg type including the one or more turns; and

expand the procedural leg into the sequence of procedural sub-legs including a respective sequence of position fixes determined from the start position, speed and heading.

18. The computer-readable storage medium of claim 16 , wherein the apparatus caused to determine the ground track includes the apparatus caused to:

identify start positions of the aircraft at position fixes in the sequence of simple procedural legs, and one or more target altitudes, speeds and vertical speeds of the aircraft; and

apply the start positions, and the one or more target altitudes, speeds and vertical speeds, to a kinematic model of the aircraft to determine the ground track.

19. The computer-readable storage medium of claim 18 , wherein the ground track as determined is expressed as a path composed of the start positions interconnected by one or more of geodesics or arcs on a reference ellipsoid.

20. The computer-readable storage medium of claim 15 , wherein the apparatus caused to determine the vertical guidance includes the apparatus caused to:

determine one or more notional altitudes, speeds and vertical speeds of the aircraft over the ground track; and

apply the one or more notional altitudes, speeds and vertical speeds to a kinematic model of the aircraft to determine one or more target altitudes, speeds and vertical speeds from which the vertical guidance is determined.

21. The computer-readable storage medium of claim 20 , wherein the apparatus caused to determine the vertical guidance includes the apparatus further caused to:

identify start positions, speed and heading of the aircraft at position fixes in the sequence of procedural legs; and

apply the start positions, speed and heading, and the one or more target altitudes, speeds and vertical speeds, to the kinematic model to determine the vertical guidance as reachable altitude and speed along the ground track.