Method and Device for the Filtering of Alerts Originating from a Collision Detection System of an Aircraft

• US 20130191016A1
• Filed: 07/20/2012
• Published: 07/25/2013
• Est. Priority Date: 07/22/2011
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: BAILLON, Bertrand, FLEURY, Stphane, VITTOZ, Fabien
• Granted Patent: US 9,251,711 B2
• Time in Patent Office: Days
• US Class Current: 701/301
• CPC Class Codes: B64D 45/04 Landing aids; Safety measures to prevent collision with earth's surface
• CPC Class Codes: G05D 1/0653 during a phase of take-off or landing
• CPC Class Codes: G05D 1/0676 specially adapted for landing
• CPC Class Codes: G08G 5/02 Automatic approach or landing aids, i.e. systems in which flight data of incoming planes are processed to provide landing data landing aids fitted in or to aircraft B64D45/04; visual or acoustic landing aids B64F1/18
• CPC Class Codes: G08G 5/025 Navigation or guidance aids radar or analogous systems specially adapted for landing purposes G01S13/913
• CPC Class Codes: G08G 5/04 Anti-collision systems

Abstract

A method and a device for the filtering of alerts originating from a collision detection system of an aircraft makes it possible, by proposing a novel condition for alert disabling, to avoid an abnormal drop of an aircraft in the case of a CFIT (controlled flight into terrain) by authorizing the output of the alert when this novel condition is not complied with. This novel condition relies on a method for thresholding the angle of approach of the aircraft (FPA for flight path angle) as a function of the altitude of the aircraft with respect to the runway and of the angle of approach specified for each runway and which is recovered via the terrain database.

Claims

1. A method for the filtering of alerts originating from a terrain collision detection system embedded aboard an aircraft in a landing runway approach phase, said aircraft flying according to a speed vector (V), said landing runway comprising a runway threshold (G), comprising the following steps:

determination of an angle of descent (α

) defined on the basis of approach procedures predefined for said landing runway,

determination of a factor (k) defined on the basis of said angle of descent (α

), of the altitude (H) of the aircraft with respect to the landing runway and of the distance x on the ground between the aircraft and the runway threshold (G),

determination of a first threshold (S₁) on the basis of the angle of approach (FPA) of the aircraft, the angle of approach (FPA) of the aircraft being the angle between the speed vector (V) of the aircraft and a horizontal line, and

disabling of the terrain alert, if the factor (k) is positive and is less than the first determined threshold (S1) and if the angle of approach (FPA) of the aircraft is less than a predetermined second threshold (FPA_max).

2. The method for the filtering of alerts according to claim 1, wherein said angle of descent (α

) is equal to the maximum of the angles of approach which are defined by approach procedures predefined for the landing runway.

3. The method for the filtering of alerts according to claim 1, wherein the factor k is computed on the basis of the following relation:

k=(H−

y)/y

where H is the difference in altitude between the aircraft and the threshold of the runway G, and where y follows the following relation;

y=x.tang(α

),

with α

the angle of descent defined on the basis of the approach procedures predefined for the runway and x the distance on the ground between the aircraft and the runway threshold G.

4. The method for the filtering of alerts according to claim 1, wherein the first threshold (S₁) is computed on the basis of the following relation:

S1=(FPA−

α

)/(FPA_Max−

α

)

where FPA is the angle of approach of the aircraft, α

the angle of descent defined on the basis of the predefined approach procedures and FPA_Max the second threshold.

5. The method for the filtering of alerts according to claim 1, wherein the first threshold (S₁) is computed as a function of the angle of approach of the aircraft FPA and according to a piecewise linear function.

6. The method for the filtering of alerts according to claim 1, said method being activated when the aircraft is situated between a first point (S) and the runway threshold (G), the first point (S) being situated at a distance (Δ

) upstream of the runway threshold (G) and placed so that the segment formed by said runway threshold (G) and said first point (S) is situated in the longitudinal axis of the runway, the distance (Δ

) being related to the precision of navigation of the aircraft.

7. A device for the filtering of alerts originating from a terrain collision detection system embedded aboard an aircraft in a landing runway approach phase, said aircraft flying according to a speed vector (V), said landing runway comprising a runway threshold (G), comprising:

means for determining an angle of descent a defined on the basis of approach procedures predefined for the said landing runway,

means for determining a factor k defined on the basis of said angle of descent (α

), of the altitude (H) of the aircraft with respect to the landing runway and of the distance (x) on the ground between the aircraft and the runway threshold (G)

means for determining a first threshold (S₁) on the basis of an angle of approach (FPA) of the aircraft, the angle of approach (FPA) of the aircraft being the angle between the speed vector (V) of the aircraft and a horizontal line, and

means for disabling the terrain alert, if the factor k is positive and is less than the first determined threshold (S1) and if said angle of approach (FPA) of the aircraft is less than a predetermined second threshold (FPA_max).

8. The device for the filtering of alerts according to claim 7, further comprising a temporal confirmer linked to the disabling means, said disabling means being able to emit a disabling signal, the confirmer transmitting the disabling signal so as to disable the terrain alert only if the disabling signal is maintained for at least a predetermined duration.

9. The device for the filtering of alerts according to claim 7, wherein said terrain alert disabling means are activated when the aircraft is situated between a first point (S) and the runway threshold (G), the first point (S) being situated at a distance (Δ

) upstream of the runway threshold (G) and placed so that the segment formed by the said runway threshold (G) and said first point (S) is situated in the longitudinal axis of the runway, the distance (Δ

) being related to the precision of navigation of the aircraft.