FLIGHT CONTROL SYSTEM WITH SYNTHETIC INTERTIAL GLIDESLOPE DEVIATION AND METHOD OF USE

• US 20180120850A1
• Filed: 11/01/2016
• Published: 05/03/2018
• Est. Priority Date: 11/01/2016
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: McLees, Robert E., Freeman, Robert Erik, Panyakeow, Prachya
• Granted Patent: US 10,203,693 B2
• Time in Patent Office: Days
• CPC Class Codes: B64D 45/04 Landing aids; Safety measures to prevent collision with earth's surface
• CPC Class Codes: G01C 21/1652 with ranging devices, e.g. LIDAR or RADAR
• CPC Class Codes: G01C 23/005 Flight directors indicating arrangements specially adapted for rotary gyroscopes G01C19/32
• CPC Class Codes: G05D 1/0202 specially adapted to aircraft
• 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

Abstract

A flight control module for computing glideslope deviation during landing of an aircraft is provided. The flight control module includes a communication interface and a processor. The communication interface is configured to receive inertial data for the aircraft. The processor is coupled to the communication interface and configured to compute an inertial glideslope deviation based on the inertial data.

Claims

1. A flight control module for computing glideslope deviation during landing of an aircraft, comprising:

a communication interface configured to receive inertial data for said aircraft;

a processor coupled to said communication interface and configured to compute an inertial glideslope deviation based on the inertial data.

2. The flight control module of claim 1, wherein said communication interface is further configured to receive first and second glideslope deviation signals indicative of respective glideslope deviations computed based on a glideslope transmission received by said aircraft.

3. The flight control module of claim 2 further comprising a signal selection fault detection (SSFD) module configured to select one glideslope deviation from among the respective glideslope deviations and the inertial glideslope deviation for use in controlling an automated landing system of said aircraft.

4. The flight control module of claim 3, wherein said SSFD module comprises a mid-value selector configured to select a middle value from among the respective glideslope deviations and the inertial glideslope deviation.

5. The flight control module of claim 1, wherein said processor comprises a complementary filter configured to generate a filtered glideslope deviation based on a glideslope deviation signal received through said communication interface and the inertial data, including a vertical acceleration and a vertical velocity.

6. The flight control module of claim 5, wherein said communication interface is configured to be coupled to an inertial reference unit (IRU) through a communication bus, the IRU comprising a ground speed sensor, a pitch sensor, a vertical velocity sensor, and a vertical acceleration sensor, and wherein the inertial data includes a ground speed, a pitch angle, the vertical velocity, and the vertical acceleration.

7. The flight control module of claim 6, wherein said communication interface is further coupled to a radar altimeter configured to measure an altitude of said aircraft and transmit an altitude signal indicative of the altitude onto said communication bus, and wherein said processor is further configured to compute the inertial glideslope deviation when the altitude falls below a predetermined threshold.

8. The flight control module of claim 7, wherein said processor is further configured to:

compute an inertial glideslope error with respect to the IRU based on the ground speed, the vertical velocity, and an average glideslope angle computed based on the ground speed and the vertical velocity; and

apply a correction to the inertial glideslope error to generate the inertial glideslope deviation, the correction computed based on the pitch attitude and a distance between the IRU and a guidance control point of said aircraft.

9. A flight control system for landing an aircraft, said flight control system comprising:

a communication bus;

first and second multi-mode receivers (MMRs) coupled to said communication bus and configured to;

compute first and second glideslope deviations based on received glideslope signals, and

transmit first and second glideslope deviation signals indicative of the first and second glideslope deviations onto said communication bus; and

a flight control module coupled to said communication bus and configured to;

receive inertial data for the aircraft and the first and second glideslope deviation signals over said communication bus,

compute an inertial glideslope deviation based on the inertial data,

select one glideslope deviation from among the first and second glideslope deviations and the inertial glideslope deviation, and

transmit the one glideslope deviation to an automated landing system for said aircraft.

10. The flight control system of claim 9 further comprising an actuator control module coupled to said automated landing system through a second communication bus, said actuator control module communicably coupled to a flight control actuator, said automated landing system configured to instruct said actuator control module according to the one glideslope deviation.

11. The flight control system of claim 9 further comprising a radar altimeter configured to detect an altitude of said aircraft, said radar altimeter coupled to said communication bus, wherein said flight control module is further configured to compute the inertial glideslope deviation when the altitude falls below a predetermined threshold.

12. The flight control system of claim 11, wherein said flight control module is further configured to compute the inertial glideslope deviation when the altitude falls below the predetermined threshold of 200 feet.

13. The flight control system of claim 11, wherein said flight control module is further configured to select a mid-value from among the first and second glideslope deviations and the inertial glideslope deviation as the one glideslope deviation for transmission to said automated landing system.

14. The flight control system of claim 11, wherein said flight control module is further configured to initialize computation of the inertial glideslope deviation based on at least one of the first and second glideslope deviation signals when said aircraft descends below 200 feet in altitude.

15. A method of detecting a glideslope deviation for an aircraft during landing, said method comprising:

receiving instrument landing system (ILS) glideslope signals;

computing multi-mode receiver (MMR) glideslope deviations with respect to a main landing gear of the aircraft based on the ILS glideslope signals;

filtering the MMR glideslope deviations;

translating a filtered MMR glideslope deviation from the main landing gear to a guidance control point (GCP) for the aircraft;

initializing an inertial glideslope deviation computation based on the filtered MMR glideslope deviation;

integrating inertial data, generated by an inertial reference unit (IRU) for the aircraft, from the filtered MMR glideslope deviation to generate an inertial glideslope deviation with respect to the IRU; and

translating the inertial glideslope deviation from the IRU to the GCP.

16. The method of claim 15, wherein filtering the MMR glideslope deviations comprises blending a vertical acceleration and a vertical velocity, both measured by the IRU, with the MMR glideslope deviations using a complementary filter.

17. The method of claim 15, wherein integrating the inertial data generated by the IRU comprises:

computing inertial glideslope error based on ground speed and vertical velocity measured by the IRU, and an average glideslope angle computed based on the ground speed and the vertical velocity; and

integrating the inertial glideslope error from the filtered MMR glideslope deviation to generate the inertial glideslope deviation with respect to the IRU.

18. The method of claim 15, wherein translating the filtered MMR glideslope deviation from the main landing gear to the GCP for the aircraft further comprises:

computing a vertical position difference between the main landing gear and the GCP based on a pitch attitude measured by the IRU; and

applying the vertical position difference to the filtered MMR glideslope deviation.

19. The method of claim 15, wherein translating the inertial glideslope deviation at the IRU to the GCP comprises:

computing a vertical position difference between the IRU and the GCP based on a pitch attitude measured by the IRU; and

adding the vertical position difference to the inertial glideslope deviation with respect to the IRU to generate an inertial glideslope deviation with respect to the GCP.

20. The method of claim 15, wherein initializing the inertial glideslope deviation computation comprises latching the filtered MMR glideslope deviation upon an altitude of the aircraft falling below a predetermined threshold.