METHOD AND DEVICE FOR VERTICALLY GUIDING AN AIRCRAFT DURING AN APPROACH OF A RUNWAY ALONG A LATERAL APPROACH TRAJECTORY

• US 20150203214A1
• Filed: 12/30/2014
• Published: 07/23/2015
• Est. Priority Date: 01/03/2014
• Status: Active Grant

• Current Assignee: Airbus Operations (European Aeronautic Defence and Space Company EADS NV)
• Original Assignee: Airbus Operations (European Aeronautic Defence and Space Company EADS NV)
• Inventors: Bourret, Thierry, AHUALLE HORIMOTO, Kenji
• Granted Patent: US 9,561,868 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B64C 13/18 using automatic pilot
• CPC Class Codes: B64D 45/04 Landing aids; Safety measures to prevent collision with earth's surface
• CPC Class Codes: G01C 23/005 Flight directors indicating arrangements specially adapted for rotary gyroscopes G01C19/32
• CPC Class Codes: G05D 1/042 specially adapted for aircraft
• CPC Class Codes: G05D 1/0676 specially adapted for landing

Abstract

A method and device including a unit to extract a linear terrain profile stored in memory, a terrain height for a current distance of the aircraft, a unit for determining a current height of the aircraft with respect to the terrain, using at least one measurement taken by a radar altimeter, a unit for computing a first current altitude of the aircraft, using the terrain height and the current height, a unit for computing a second current altitude of the aircraft, corresponding to an altitude on an approach profile of the current position of the aircraft and a unit for computing the difference between the first and second current altitudes, the difference being transmitted to a guidance unit to vertically guide the aircraft.

Claims

1. A method of vertical guidance of an aircraft during an approach to a landing runway along a lateral approach trajectory, the method comprising successive steps of automatically and repeatedly:

a) determining a current distance corresponding to a distance in a lateral plane along the lateral approach trajectory, between a current position of the aircraft and a threshold of the landing runway;

b) extracting from a linear terrain profile defined along the lateral approach trajectory, a terrain height for the current distance, the terrain height being defined with respect to a level of the threshold of the landing runway;

c) determining a current height of the aircraft with respect to the terrain, using at least one measurement taken by at least one on-board radar altimeter at the current position;

d) computing a first current altitude of the aircraft, with respect to the level of the threshold of the landing runway, using the current height of the aircraft and of the terrain height;

e) computing a second current altitude of the aircraft, with respect to the level of the threshold of the landing runway, corresponding to an altitude on an approach profile for the current distance;

f) computing the difference between the first and second current altitudes; and

g) using the difference to vertically guide the aircraft.

2. The method of claim 1,

wherein step a) comprises sub-steps comprising:

determining the current position of the aircraft, using measurements taken by an on-board receiver forming part of a satellite positioning system; and

computing the current distance, using the current position and a stored predetermined position of the threshold of the landing runway.

3. The method of claim 1,

wherein step c) comprises determining the current height to be a height measured by the radar altimeter.

4. The method of claim 1,

wherein step c) comprises determining the current height to be a hybrid height, by implementing successive sub-steps comprising:

c1) filtering, using a low-pass filter, a measurement taken by the radar altimeter to obtain a first value;

c2) measuring the vertical speed of the aircraft, in integrating the vertical speed, and in filtering it, using a high-pass filter, to obtain a second value; and

c3) summing the first and second values to obtain the hybrid height.

5. The method of claim 1, wherein step d) comprises summing the current height and the terrain height to compute the first current altitude.

6. The method of claim 1, wherein a position correction on the aircraft, between an on-board receiver forming part of a satellite positioning system and an on-board radar altimeter, is implemented repeatedly using the current angle of inclination and the relative positions of the antennas of the aircraft, referencing the measurements taken by the receiver and the measurements taken by the radar altimeter with respect to one and the same reference point situated on the aircraft.

7. The method of claim 1, wherein step e) comprises sub-steps comprising:

e1) computing an approach profile corresponding to a half-line having a predetermined angle with respect to the horizontal and comprising an endpoint that is situated on the landing runway at a predetermined distance with respect to the threshold of the landing runway; and

e2) computing, as second current altitude, the altitude of the approach profile at a lateral distance from the threshold of the landing runway corresponding to the current distance.

8. The method of claim 1, wherein an alert signal is emitted in the cockpit of the aircraft when the accuracy of the current position of the aircraft is below a predetermined accuracy threshold, the current position and the accuracy being determined using an on-board receiver forming part of a satellite positioning system.

9. The method of claim 1, comprising an additional step comprising estimating a bias in the current distance of the aircraft and in correcting the current distance by the bias.

10. The method of claim 9, wherein the additional step comprises sub-steps comprising, during the approach,:

α

) estimating the profile of the terrain overflown, using the measurements taken; and

β

) correlating the profile of the terrain overflown, with a terrain profile stored in memory in such a way as to deduce a bias therefrom,

the steps α

) and β

) being repeated iteratively, taking into account at each iteration the bias deduced in the preceding iteration.

11. The method of claim 1, wherein a difference between the first and second current altitudes is expressed in the form of an angular deviation between two half-lines.

12. The method of claim 1, comprising an additional step comprising displaying the difference on a screen of the cockpit.

13. A device for vertical guidance of an aircraft during an approach to a landing runway along a lateral approach trajectory, the vertical guidance device comprising at least the following on-board units:

a tracking unit for determining a current position of the aircraft;

at least one radar altimeter and at least one guidance unit; and

the device further comprising on-board units comprising;

a database storing a linear terrain profile defined along the lateral approach trajectory;

a first computing unit configured to determine a current distance corresponding to a distance in a lateral plane along the lateral approach trajectory, between the current position of the aircraft and a threshold of the landing runway;

a second computing unit configured to extract from the linear terrain profile stored in the database, a terrain height for the current distance, determined by the first computing unit, the terrain height defined with respect to a level of the threshold of the landing runway;

a third computing unit configured to determine a current height of the aircraft with respect to the terrain, using at least one measurement taken by the radar altimeter at the current position;

a fourth computing unit configured to compute a first current altitude of the aircraft, with respect to the level of the threshold of the landing runway, using the terrain height and the current height of the aircraft, received from the second and third computing units respectively;

a fifth computing unit configured to compute a second current altitude of the aircraft, with respect to the level of the threshold of the landing runway, corresponding to an altitude on an approach profile of the current position; and

a sixth computing unit configured to compute a difference between the first and second current altitudes, received from the fourth and fifth computing units, respectively, the difference being transmitted to the guidance unit that uses it to vertically guide the aircraft.

14. The device of claim 13, wherein the guidance unit comprises at least one of the following units:

an automatic pilot system and a flight director.

15. An aircraft comprising a vertical guidance device according to claim 13.