# US 2018/0024237 A1 · Method and device for determining the position of an aircraft in an approach for a landing

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- Number: US 2018/0024237 A1
- Document ID: US20180024237A1
- Status: Published application
- Kind: A1
- Application number: 15/653,709
- Filed: 2017-07-19
- Published: 2018-01-25
- Earliest claimed: 2016-07-21
- Assignees: Airbus Operations GmbH
- Applicants: Airbus Operations SAS
- Inventors: Olivier LAPLACE; Camille CARUHEL; Pascal LAURENS
- Web page: https://patentgrep.com/patent/US20180024237A1

## CPC

- G01S 13/935: for terrain-avoidance
- B64D 45/04: Landing aids; Safety measures to prevent collision with earth's surface
- G01C 23/00: Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed or acceleration
- G01S 1/00: Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith (position fixing by co-ordinating a plurality of determinations of direction or position lines G01S5/00)
- G01S 11/12: using electromagnetic waves other than radio waves
- G01S 13/86: Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
- G01S 13/89: for mapping or imaging
- G01S 13/91: for traffic control (G01S13/93 takes precedence)
- G01S 13/913: {for landing purposes}
- G01S 13/933: of aircraft or spacecraft
- G01S 19/49: whereby the further system is an inertial position system, e.g. loosely-coupled
- G05D 1/0684: {on a moving platform, e.g. aircraft carrier}
- G06T 7/73: using feature-based methods
- G06V 10/143: Sensing or illuminating at different wavelengths
- G06V 20/13: Satellite images
- G06V 20/588: {Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road}
- G01S 2013/916: {Airport surface monitoring [ASDE]}
- G06T 2207/10044: Radar image
- G06T 2207/30184: Infrastructure
- G06T 2207/30204: Marker
- G06T 2207/30256: Lane; Road marking
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING

## Abstract

A device comprising a radar for taking at least one radar image of the terrain in front of the aircraft in a zone containing at least one characteristic pattern, the position of the characteristic pattern being known, an image processing unit for detecting, on the radar image taken by the radar, a characteristic symbol representing the characteristic pattern, a computation unit for determining, from at least the position of the characteristic symbol in the image and from characteristics of the radar image acquisition, relative position information illustrating the position of the aircraft in relation to the characteristic pattern, and for determining the position of the aircraft, from the relative position information and from the known position of the characteristic pattern, and a unit for transmitting at least the position of the aircraft to at least one user system, for example a landing aiding system or an SVS display.

## Claims

### Claim 1

A method for determining the position of an aircraft in an approach for a landing, the method comprising a series of steps comprising:
a radar image acquisition step, implemented by at least one radar mounted on the aircraft, the acquisition step comprising taking at least one radar image of the terrain in front of the aircraft in a zone containing at least one characteristic pattern, the position of said characteristic pattern being known;
an image processing step, implemented by an image processing unit and comprising at least detecting, on the radar image, a characteristic symbol representing said characteristic pattern;
a computation step, implemented by a computation unit and comprising determining, from at least the position of the characteristic symbol in the radar image and from characteristics of the radar image acquisition, relative position information illustrating the position of the aircraft in relation to the characteristic pattern, and determining the position of the aircraft from said relative position information and from the known position of the characteristic pattern;
an updating step, implemented by an updating unit, after the computation step, and comprising determining an updated position of the aircraft by updating an operational position of the aircraft, using said position of the aircraft determined in the computation step; and
a data transmission step, implemented by a data transmission unit and comprising transmitting at least said updated position of the aircraft to at least one user system.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein:
the image processing step also comprises determining a deformation of the characteristic symbol in the radar image, due to the perspective linked to the angle from which the characteristic pattern is seen from the radar mounted on the aircraft during the radar image capture; and
the computation step uses the deformation of the characteristic symbol thus determined, to determine the attitude and the heading of the aircraft.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the image processing step implements a consolidation of the detection of the characteristic pattern.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein the characteristic pattern represents at least one of the following elements:
a landing runway used for the landing;
at least one reflecting device, which exhibits a reflectivity greater than that of the terrain and which is installed on the terrain; and
a natural configuration of the terrain.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein the image processing step uses a shape recognition method.

### Claim 6 (depends on 1)

The method as claimed in claim 1, wherein the series of steps comprises a monitoring step, implemented by a monitoring unit, after the computation step, and comprising checking the consistency of the position of the aircraft determined in the computation step.

### Claim 7 (depends on 1)

The method as claimed in claim 1, wherein the series of steps comprises a step of extrapolation of the position of the aircraft, the extrapolation step being implemented by an extrapolation unit between two positions determined from two successive radar images of the characteristic pattern, the extrapolation step being implemented using auxiliary data, from at least one system other than the radar.

### Claim 8 (depends on 1)

The method as claimed in claim 1, wherein the series of steps is implemented, repetitively, during the approach.

### Claim 9 (depends on 8)

The method as claimed in claim 8, wherein the series of steps is implemented early, before a given approach phase corresponding to a part of the approach, checks being carried out on the results obtained then, and the results of the series of steps obtained during the given approach phase being used during this approach phase only if given conditions, partly relating to said checks, are met.

### Claim 10

A device for determining the position of an aircraft in an approach for a landing, the device comprising:
at least one radar configured to take at least one radar image of the terrain in front of the aircraft in a zone containing at least one characteristic pattern, the position of said characteristic pattern being known;
an image processing unit configured to detect, on the radar image taken by the radar, a characteristic symbol representing said characteristic pattern;
a computation unit configured to determine, from at least the position of the characteristic symbol in the image and characteristics of the radar image acquisition, so-called relative position information illustrating the position of the aircraft in relation to the characteristic pattern, and to determine the position of the aircraft, from said relative position information and from the known position of the characteristic pattern;
an updating unit configured to determine an updated position of the aircraft by updating a so-called operational position of the aircraft using said position of the aircraft; and
a data transmission unit configured to transmit at least said updated position of the aircraft to at least one user system.

### Claim 11 (depends on 10)

The device as claimed in claim 10, further comprising at least one of the following units:
an extrapolation unit configured to extrapolate the position of the aircraft; and
a monitoring unit configured to check the consistency at least of the position of the aircraft.

### Claim 12 (depends on 10)

A landing aiding system, comprising at least one device for determining the position of an aircraft as claimed in claim 10.

### Claim 13 (depends on 12)

The landing aiding system as claimed in claim 12, further comprising two devices for determining the position of an aircraft, independent of one another, and being configured to implement an automatic landing of the aircraft.

### Claim 14 (depends on 12)

The landing aiding system as claimed in claim 12, further comprising a synthetic vision system using at least the position determined by the device for determining the position, to assist in the display.