METHOD AND DEVICE FOR MONITORING A POSITION INDICATION OF AN AIRCRAFT

• US 20080294306A1
• Filed: 05/19/2008
• Published: 11/27/2008
• Est. Priority Date: 05/23/2007
• Status: Active Grant

• Current Assignee: Airbus Operations SAS (Airbus SE)
• Original Assignee: Airbus France
• Inventors: Ortet, Gregory, Guillet, Alain, Dattler, Stephane, Huynh, Jean-Philippe
• Granted Patent: US 7,908,046 B2
• Time in Patent Office: Days
• US Class Current: 701/3
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled
• CPC Class Codes: G08G 5/006 in accordance with predefined flight zones, e.g. to avoid prohibited zones

Abstract

The device (1) comprises means (8, 9, 10) for calculating a global error relating to a position indication of the aircraft, means (13) for comparing this global error with a threshold value which depends on the flight constraints, and alarm means (15).

Claims

1. A method for monitoring a position indication of an aircraft, said position indication representing a current position of the aircraft, which is determined with the aid of information arising from onboard positioning means (3) cooperating with a satellite positioning system and of inertial information generated by an onboard inertial system (4),

wherein the following series of successive operations is carried out in an automatic and repetitive manner:

a) at least one first position error which represents an estimated maximum error of said position indication of the aircraft is determined;

b) at least one second position error which represents an estimated maximum error of the position of the aircraft for a particular future duration, and which depends on a problem in determining said position indication, is determined;

c) at least the sum of said first and second position errors is formed so as to obtain a global error;

d) this global error is compared with at least one threshold value which depends on flight constraints of the aircraft which must fly inside a predetermined flight corridor; and

e) if said global error is greater than said threshold value, an alarm signal is emitted.

2. The method as claimed in claim 1,

wherein said inertial system (4) comprises several inertial platforms, each of said inertial platforms making it possible to determine a current position of the aircraft, in step a) a plurality of first position errors is determined, each of these first position errors relating to one of these current positions and being associated with the inertial platform which has determined the corresponding current position, in step b) a plurality of second position errors associated respectively with said inertial platforms is determined, and in step c) the sum of first and second position errors which are associated with the same inertial platform is formed so as to obtain a plurality of sums, and said global error is determined on the basis of this plurality of sums.

3. The method as claimed in claim 1,

wherein, in step b), said second position error is determined by assuming a total loss of the information arising from said onboard positioning means (3) which cooperate with a satellite positioning system.

4. The method as claimed in claim 1,

wherein that, in step b), said second position error is determined by taking account of the flight dynamics relating to the future flight of the aircraft over said future duration.

5. The method as claimed in claim 1,

wherein, in step d), a plurality of threshold values is envisaged and the global error is compared with each of these threshold values, and in step e), in the event that an alarm signal is emitted, the threshold values which are exceeded by said global error are indicated.

6. The method as claimed in claim 1,

wherein, upon the emission of an alarm signal in step e), an additional step f) is carried out, in which the inertial system (4) calculates, in an automatic and repetitive manner, a current position with the aid of a pure-inertia mode, for which the information arising from at least one receiver of said onboard positioning means (3) are discarded from the position calculation after the emission of the alarm signal.

7. The method as claimed in claim 6,

wherein said inertial system (4) comprises a plurality of inertial platforms, each of which calculates a current position, and in step f), a consolidated current position of the aircraft is determined on the basis of these various current positions.

8. The method as claimed in claim 6,

wherein, upon the emission of an alarm signal in step e), steps a) to e) continue to be carried out in an automatic and repetitive manner, and as soon as the global error again becomes less than the threshold value, the inertial system (4) ceases the calculation of the current position with the aid of the pure-inertia mode, such as provided for in step f).

9. The method as claimed in claim 1,

wherein said flight constraints relate to required navigation and guidance performance.

10. A device for monitoring a position indication of an aircraft, said position indication representing a current position of the aircraft and being determined with the aid of information arising from onboard positioning means (3) cooperating with a satellite positioning system and of inertial information generated by an onboard inertial system (4),

wherein it comprises:

means (8) for determining at least one first position error which represents an estimated maximum error of said position indication of the aircraft;

means (9) for determining at least one second position error which represents an estimated maximum error of the position of the aircraft for a particular future duration, and which depends on a problem in determining said position indication;

means (10) for forming at least the sum of said first and second position errors so as to obtain a global error;

means (13) for comparing this global error with at least one threshold value which depends on flight constraints of the aircraft which must fly inside a predetermined flight corridor; and

means (15) for emitting an alarm signal if said global error is greater than said threshold value.