Method of Guidance for Aircraft Trajectory Correction

• US 20130206922A1
• Filed: 11/16/2012
• Published: 08/15/2013
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: RIEDINGER, Marc, LISSAJOUX, Sylvain, BELY, Anne-Sophie
• Granted Patent: US 9,045,221 B2
• Time in Patent Office: Days
• US Class Current: 244/76.C
• CPC Class Codes: B64C 13/16 actuated automatically, e.g. responsive to gust detectors
• CPC Class Codes: G05D 1/0204 to counteract a sudden perturbation, e.g. cross-wind, gust

Abstract

Guidance for an aircraft correcting a trajectory deviation due to wind computes a roll command during trajectory alignment according to imposed alignment passing through a determined point, via a current angular divergence between a line through the point and aircraft and direction of alignment and of a current estimated ground speed of the aircraft with respect to a frame of reference. The current estimated ground speed is computed via a current air speed and stored wind speed. The stored wind speed is obtained via at least one wind speed computed via a first value of a first speed equal to the speed of the said aircraft with respect to a frame of reference originating from a satellite navigation system and a second value of a second speed equal to the air speed. The first and second value are simultaneously accounted earlier than or at the instant at the alignment phase.

Claims

1. A guidance method of an aircraft for correcting a trajectory deviation due to the presence of wind, comprising a step of computing a roll command of the aircraft during a phase of alignment of the trajectory of the aircraft according to an imposed direction of alignment passing through a determined point, on the basis:

of a current angular divergence between a straight line passing through the said determined point and the aircraft on the one hand and the said direction of alignment on the other hand, and

of a current estimated ground speed of the aircraft with respect to a frame of reference tied to the ground,

said current estimated ground speed being computed on the basis of a current air speed of the aircraft with respect to the surrounding air and of a stored wind speed,

said stored wind speed being obtained on the basis of at least one wind speed computed on the basis;

of a first value of a first speed equal to the speed of the said aircraft with respect to a frame of reference tied to the ground originating from a satellite navigation system, and

of a second value of a second speed equal to the said air speed with respect to the surrounding air,

said first value and second value being taken into account simultaneously at at least one instant earlier than or equal to the instant at which the aircraft starts the said alignment phase.

2. The guidance method according to claim 1 wherein the said current estimated speed is equal to the vector sum of the said current air speed and of the said stored wind speed.

3. The guidance method according to claim 1 wherein the said stored wind speed is obtained on the basis of at least one wind speed determined at at least one instant earlier than or equal to the instant at which the aircraft starts the said alignment phase.

4. The guidance method according to claim 1 wherein the said wind speed is equal to the vector difference between the said first speed and the said second speed.

5. The guidance method according to claim 1 wherein the said stored wind speed is equal to the said wind speed computed at the said instant at which the aircraft starts the said alignment phase.

6. The guidance method according to claim 1 wherein the said stored wind speed is the result of a digital processing performed on the basis of wind speeds computed over a plurality of instants

7. The guidance method according to claim 6 wherein the said digital processing is a temporal average of wind speeds computed at a plurality of instants

8. The method according to claim 1 wherein the said computing step uses a magnetic declination datum provided by an additional onboard system so as to express the said speeds in one and the same reference frame.

9. The method according to claim 1 wherein the said imposed direction of alignment is determined by a beacon situated on the ground constituting the said determined point which emits a signal and which generates a directional beam.

10. The method according to claim 9 wherein the instant at which the aircraft starts the said alignment phase corresponds to the instant from which the detector of the said signal situated on the aircraft exhibits a response proportional to the said angular divergence.

11. The method according to claim 1 wherein the said computing step is able to compute a roll command on the basis of the said speed of the aircraft with respect to the air as replacement for the said current estimated ground speed of the aircraft.

12. The method according to claim 11 wherein when the data originating from the said satellite navigation system are not provided by the said navigation system or are erroneous, the said current estimated ground speed of the aircraft is replaced with the said current air speed of the aircraft for the said computation of the said roll command.

13. A system for the guidance of an aircraft able to correct a trajectory deviation due to the presence of wind comprising:

a computation module for computing a roll command for the aircraft during a phase of alignment of the trajectory of the aircraft according to an imposed direction of alignment passing through a determined point, on the basis;

of a current angular divergence between a straight line passing through the said determined point and the aircraft on the one hand and the said direction of alignment on the other hand, and

of a current estimated ground speed of the aircraft with respect to a frame of reference tied to the ground,

a computation module for computing the said current estimated ground speed of the aircraft on the basis of a current air speed of the aircraft with respect to the surrounding air and of a stored wind speed,

a computation module for computing the said stored wind speed on the basis;

of a first value of a first speed equal to the speed with respect to a frame of reference tied to the ground of the said aircraft originating from a satellite navigation system, and

of a second value of a second speed equal to the said air speed with respect to the surrounding air,

the said first value and second value being taken into account simultaneously at at least one instant earlier than or equal to the instant at which the aircraft starts the said alignment phase.