Method and system for determining an airspeed of an aircraft

• US 9,234,909 B2
• Filed: 05/02/2014
• Issued: 01/12/2016
• Est. Priority Date: 05/03/2013
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Meulle, Guillaume, Caussat, Thomas, Beaufils, Arnaud, Pierre, Christophe
• Primary Examiner(s): MARC-COLEMAN, MARTHE Y
• Application Number:
  US14/268,816
• Publication Number:
  US 20140330458A1
• Time in Patent Office: 620 Days
• Field of Search: 701/11, 701/14, 340/968, 342/104, 342/115
• US Class Current: 1/1
• CPC Class Codes: B64C 19/00 Aircraft control not otherwise provided for
• CPC Class Codes: G01P 5/00 Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft application of speed-measuring devices for measuring volume of fluid G01F

Abstract

A method and system for determining an airspeed of an aircraft, known as assisted aircraft, comprises: a) determining a position; b) measuring a ground speed; c) receiving a plurality of messages from a plurality of other assisting, aircraft, each message containing a first item of information, indicating a position of an assisting aircraft, and a second item of information, indicating a wind speed at the position; d) estimating a wind speed at the position of the assisted aircraft by interpolating the wind speed values at the positions of the assisting aircraft obtained in step c); and e) computing a true speed of the assisted aircraft by using the vector difference between its ground speed, measured in step b), and the wind speed estimated in step d). The method can check operation of an anemometric subsystem aboard an aircraft, to compensate for any malfunction and/or to enable automatic piloting.

Claims

1. A method for determining an airspeed of an assisted aircraft, comprising the following steps:

a) determining a position of said assisted aircraft;

b) measuring a ground speed of said assisted aircraft;

c) receiving a plurality of messages from a plurality of other aircraft, called assisting aircraft, each said message containing;

a first item of information, indicating a position of a said assisting aircraft, and a second item of information, indicating a wind speed at said position;

d) estimating a wind speed at the position of said assisted aircraft by interpolating the wind speed values at the positions of said assisting aircraft obtained in said step c); and

e) computing a true speed TAS of said assisted aircraft by using a vector difference between its ground speed, measured in said step b), and the wind speed estimated in said step d),

wherein;

said steps a) and b) are implemented by at least one device aboard said assisted aircraft and chosen from among;

a GNSS receiver and an inertial control centre;

said step c) is implemented by a receiver aboard said assisted aircraft; and

said steps d) and e) are implemented by a processor.

2. The method according to claim 1, also comprising the following step:

f) computing, based on the true speed computed in said step e), at least one parameter chosen from among a Calibrated Air Speed CAS and a Mach number.

3. The method according to claim 1, wherein said steps a) and b) are implemented by means of at least one device (RSN) aboard said assisted aircraft and chosen from among:

a GNSS receiver and an inertial control centre.

4. The method according to claim 1, wherein said messages are broadcast by said assisting aircraft.

5. The method according to claim 4, wherein said messages are broadcast by said assisting aircraft and received by said assisted aircraft according to an ADS-B protocol.

6. The method according to claim 1, wherein said second item of information comprises a ground speed measurement and an airspeed measurement for said assisting aircraft, from which said wind speed can be deduced.

7. The method according to claim 1, wherein at least said steps d) and e) are performed by a processor aboard said assisted aircraft.

8. The method according to claim 1, wherein said step d) is implemented by kriging.

9. The method according to claim 1, wherein said steps c) and d) comprise:

receiving a predefined number N of said messages, extracting the first and second items of information contained in these messages and storing them in a queue of length N;

computing a first estimation of said wind speed by interpolating from the information stored in said queue;

on subsequently receiving other said messages, storing the information contained in said queue and concomitantly removing older information from said queue, according to the first in first out principle; and

computing a new estimation of said wind speed by interpolating from the information stored in the queue modified thus.

10. The method according to claim 1, also comprising determining an uncertainty parameter of said airspeed of said assisted aircraft.

11. The method according to claim 1, wherein said messages also contain a third item of information representing the pressure at sea level corresponding to the position of each said assisting aircraft, the method also including a step of estimating the pressure at sea level corresponding to the position of said assisted aircraft by interpolating said third items of information.

12. A method for checking an operation of an anemometric subsystem aboard an aircraft, known as an assisted aircraft, comprising the following steps:

measuring an airspeed of said assisted aircraft by means of said anemometric subsystem;

determining said airspeed of said aircraft, as well as its uncertainty parameter, by using a method according to claim 9; and

considering that said anemometric subsystem is faulty when a difference between said measured speed and said determined speed exceeds said uncertainty parameter.

13. A method for automatic piloting of an aircraft, called an assisted aircraft, including the following steps:

i) determining an airspeed of said assisted aircraft as well as an uncertainty parameter of said speed by means of a method according to claim 12;

ii) correcting upper and lower airspeed limits permitted for the flight of said aircraft while taking account of said uncertainty parameter; and

iii) using an autopilot system to maintain the airspeed of said assisted aircraft within said corrected upper and lower limits.

14. Use of a method according to claim 1 in the event of a fault in an anemometric subsystem aboard said assisted aircraft.

15. A system for determining an airspeed of an aircraft, known as an assisted aircraft, comprising:

a device for determining the position and ground speed of said aircraft;

a receiver for receiving a plurality of messages from a plurality of other aircraft, known as assisting aircraft, each said message containing;

a first item of information indicating a position of a said assisting aircraft, and a second item of information, indicating a wind speed at said position; and

a processor configured or programmed for estimating a wind speed at the position of said assisted aircraft by interpolating wind speed values at the positions of said assisting aircraft and for computing the an airspeed of said assisted aircraft by using a vector difference between its ground speed and the estimated wind speed.

16. The system according to claim 15, also comprising an anemometric subsystem for determining a wind speed or the airspeed of the aircraft, as well as a transmitter for broadcasting a message containing:

a first item of information, indicating a position of said aircraft, and a second item of information, indicating a wind speed at said position.

17. The system according to claim 15, wherein said receiver is an ADS-B receiver.

18. The system according to claim 16, wherein said receiver and said transmitter are an ADS-B receiver and transmitter respectively.

19. A method for determining an airspeed of an assisted aircraft, comprising:

a) determining a position of the assisted aircraft with at least one device aboard the assisted aircraft chosen from among;

a GNSS receiver and an inertial control centre;

b) measuring a ground speed of the assisted aircraft with the at least one device;

c) receiving a plurality of messages from a plurality of other aircraft, called assisting aircraft with a receiver aboard said assisted aircraft, each said message containing;

a first item of information, indicating a position of a the assisting aircraft, and a second item of information, indicating a wind speed at the position;

d) estimating a wind speed at the position of the assisted aircraft by interpolating the wind speed values at the positions of the assisting aircraft obtained in said step c) with a processor; and

e) computing a true speed TAS of said assisted aircraft by using a vector difference between its ground speed, measured in said step b), and the wind speed estimated in said step d) with the processor.