Method, apparatus and computer program product for estimating airplane attitude with reduced sensor set

• US 6,473,676 B2
• Filed: 12/22/2000
• Issued: 10/29/2002
• Est. Priority Date: 12/22/1999
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Oberg, Joseph M., Sample, William G., Wilson, Ronald D., Lehfeldt, James J., Katz, Kenneth P.
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US09/746,316
• Publication Number:
  US 20010039467A1
• Time in Patent Office: 676 Days
• Field of Search: 701/3, 701/4, 701/5, 701/7, 701/11, 701/13, 244/75.R, 244/158.R, 244/180, 244/181, 244/182, 244/184, 244/185, 244/171, 340/967, 340/974, 340/975
• US Class Current: 701/4
• CPC Class Codes: G01C 19/30 Erection devices, i.e. devices for restoring rotor axis to a desired position for instrument indicating the vertical G01C19/46
• CPC Class Codes: G01C 21/18 Stabilised platforms, e.g. by gyroscope
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems

Abstract

An apparatus, method and computer program product useful for supplying the pilot of an aircraft with aircraft attitude information in the event of full or partial failure of the gyroscopic system normally used to supply such data. The pitch angle, roll angle and heading angle estimates provided by the apparatus, method and computer program product can be displayed to the pilot thereby alleviating the requirement that the pilot mentally integrate such data from the remaining aircraft instruments.

Claims

1. A system for supplying the pilot of an aircraft with an alternative source of aircraft attitude information comprising:

a plurality of sensors including;

a first sensor useful for sensing aircraft linear acceleration in a vertical direction;

a second sensor useful for sensing an airspeed of the aircraft;

a third sensor useful for sensing a roll rate and yaw rate of the aircraft and oriented on an inclined axis;

a fourth sensor useful for sensing a magnetic heading of the aircraft;

a signal processor, having an input coupled to said suite of sensors, and including;

a pitch angle estimator;

a roll angle estimator;

a heading angle estimator; and

an output; and

a display for displaying an angle estimation output from said signal processor to the pilot.

2. The system of claim 1 wherein said plurality of sensors further includes a pitch level sensor.

3. The system of claim 1 wherein said plurality of sensors further includes a sixth sensor useful for sensing a roll angle of the aircraft.

4. The system of claim 1 wherein said display comprises a mechanical indicating device visible to the pilot.

5. The system of claim 1 wherein said display comprises an electronic cockpit display.

6. The system of claim 1 wherein said signal processor comprises an analog circuit.

7. The system of claim 1 wherein said signal processor comprises a microprocessor.

8. The system of claim 1 wherein said second sensor and said first sensor comprise an air data computer.

9. The system of claim 1 wherein said display comprises a mechanical indicating device visible to the pilot.

10. The system of claim 1 wherein said display comprises an electronic cockpit display.

11. The system of claim 1 wherein said heading estimator comprises an analog circuit.

12. The system of claim 1 wherein said heading estimator comprises a microprocessor.

13. A roll angle estimator system for supplying an alternate source of aircraft roll angle information comprising:

a first sensor useful for sensing an aircraft airspeed data;

a second sensor useful for sensing a turn rate, oriented on an inclined axis;

a roll angle estimator having an input coupled to said first and second sensors and having an output;

a display, coupled to said roll angle estimator output, for displaying the roll angle information to the pilot.

14. The system of claim 13 wherein said display comprises an electronic cockpit display.

15. The system of claim 13 wherein said display comprises a mechanical indicating device visible to the pilot.

16. The system of claim 13 wherein said roll angle estimator comprises an analog circuit.

17. The system of claim 13 wherein said roll angle estimator comprises a microprocessor.

18. The system of claim 13 wherein said first sensor comprises an air data computer.

19. A pitch angle estimator system for supplying an alternate source of aircraft pitch angle information comprising:

a first sensor useful for sensing an aircraft roll angle;

a second sensor useful for sensing an aircraft linear acceleration along a vertical axis;

a third sensor useful for sensing an airspeed of the aircraft;

a pitch angle estimator having an input coupled to said first, said second and said third sensors, and having an output; and

a display, coupled to said pitch angle estimator output, for displaying the pitch angle estimation to the pilot.

20. The system of claim 19 wherein said altitude sensor comprises an altimeter.

21. The system of claim 19 wherein said second sensor comprises an air data computer for sensing vertical acceleration pneumatically.

22. The system of claim 19 wherein said second sensor comprises a vertical speed indicator.

23. The system of claim 19 wherein said second sensor comprises a global positioning unit.

24. The system of claim 19 wherein said second sensor comprises an accelerometer.

25. The system of claim 19 further comprising a pitch attitude level sensor and wherein said output of said pitch attitude level sensor is coupled to said input of said pitch angle estimator.

26. The system of claim 19 wherein said display comprises a mechanical indicating device visible to the pilot.

27. The system of claim 19 wherein said display comprises an electronic cockpit display.

28. The system of claim 19 wherein said pitch angle estimator comprises an analog circuit.

29. The system of claim 19 wherein said pitch angle estimator comprises a microprocessor.

30. The system of claim 19 wherein said third sensor comprises an air data computer.

31. The system of claim 19 wherein said third sensors comprise a global positioning unit.

32. An apparatus for supplying an alternative source of aircraft attitude information comprising:

an input, adapted to receive a plurality of signals indicative of;

an aircraft linear acceleration in a vertical direction;

an airspeed of the aircraft;

an inclined turn rate sensor;

a yaw rate of the aircraft; and

a magnetic heading of the aircraft;

an output; and

a signal processor, disposed between and coupled to said input and to said output, for processing said plurality of signals and outputting at said output, an attitude estimate signal, wherein said attitude estimate signal includes at least one of a pitch angle estimate, a roll angle estimate or a heading angle estimate.

33. The apparatus of claim 32 wherein said signal processor further outputs a display control signal useful for controlling display of said attitude estimate signal on a cockpit display.

34. The apparatus of claim 32 wherein said signal processor comprises a microprocessor.

35. The apparatus of claim 32 wherein said signal processor comprises an analog circuit.

36. The apparatus of claim 32 further including an interface coupled to said signal processor and to said output for formatting said attitude estimate signal in a form useful by an avionics system contained aboard the aircraft.

37. An aircraft roll angle estimator for supplying an alternate source of aircraft roll angle information comprising:

an input adapted to receive a plurality of signals indicative of;

an aircraft airspeed;

a turn rate as measured on an inclined axis;

an output; and

a signal processor, disposed between and coupled to said input and said output, for processing said plurality of signals and outputting at said output a roll angle estimate signal, wherein said signal processor includes a feedback loop logic having the form;

$\widehat{\mathrm{\Phi <br><br>}}<br><br>\left(s\right)=G<br><br>\left(s\right)·<br><br>\left(\frac{u}{s·<br><br>u·<br><br>\sin <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\Theta <br><br>}}_G+g·<br><br>\cos <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\Theta <br><br>}}_G}\right).$

38. The apparatus of claim 37 wherein said signal processor further outputs a display control signal useful for controlling display of said heading angle estimate signal on a cockpit display.

39. The apparatus of claim 37 wherein said signal processor comprises a microprocessor.

40. The apparatus of claim 37 wherein said signal processor comprises an analog circuit.

41. The apparatus of claim 37 further including an interface coupled to said signal processor and to said output for formatting said roll angle estimate signal in a form useful by an avionics system contained aboard the aircraft.

42. A method for estimating aircraft pitch angle comprising the steps of:

receiving an aircraft roll angle signal;

receiving a first signal indicative of aircraft linear acceleration along a vertical axis;

receiving an aircraft airspeed signal;

receiving an aircraft pitch level signal;

inputting said aircraft roll angle signal, said first signal, said airspeed signal and said pitch level signal into a feedback control loop having the form;

$\widehat{\mathrm{\Phi <br><br>}}<br><br>\left(s\right)=G<br><br>\left(s\right)·<br><br>\left(\frac{u}{s·<br><br>u·<br><br>\sin <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\Theta <br><br>}}_G+g·<br><br>\cos <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\Theta <br><br>}}_G}\right).$

43. The method of claim 42 further comprising the step of receiving said roll angle signal from a roll angle estimator.

44. A method for supplying an alternative source of aircraft attitude information in the event of failure of the primary attitude sensing system comprising the steps of:

receiving a plurality of signals indicative of;

an aircraft linear acceleration in a vertical direction;

an airspeed of the aircraft;

a turn rate as measured on an inclined axis;

a magnetic heading of the aircraft; and

a pitch level sensor signal;

using said signal indicative of airspeed of the aircraft and said signal indicative of turn rate as measured on an inclined axis to assert a roll angle estimate signal;

using said roll angle estimate signal, said airspeed signal;

said pitch level sensor signal, and said aircraft linear acceleration signal to assert a pitch angle estimate signal; and

using said roll angle estimate signal;

said magnetic heading signal and said yaw rate signal to assert a heading angle estimate signal.

45. The method of claim 44 further comprising the step of using said heading angle estimate signal, said pitch angle estimate signal and said roll angle estimate signal to display a heading, a pitch and a roll data to the pilot.

46. A computer program product for supplying aircraft heading information comprising:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer-readable program code means having;

first computer instruction means for accessing a roll angle, a yaw rate and a magnetic heading data; and

a second computer instruction means for estimating aircraft heading as a function of said roll angle, said yaw rate and said magnetic heading data.

47. A computer program product for supplying aircraft roll angle information comprising:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer readable program code means having;

first computer instruction means for accessing an aircraft airspeed and a pitch angle rate data; and

second computer instruction means for estimating aircraft roll angle as a function of said aircraft airspeed and pitch angle rate data.

48. A computer program product for supplying aircraft pitch angle information comprising:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer readable program code means having;

first computer instruction means for accessing an aircraft roll angle, vertical acceleration and airspeed data; and

second computer instruction means for estimating aircraft pitch angle as a function of said aircraft roll angle, vertical acceleration and said airspeed data.

49. A computer program product for supplying aircraft attitude information comprising:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer readable program code means having;

first computer instruction means for accessing an aircraft vertical acceleration, an aircraft airspeed, a yaw rate, roll rate, and magnetic heading data; and

second computer instruction means for estimating at least one of an aircraft roll angle, an aircraft pitch angle or an aircraft heading angle according to data accessed by said first computer instruction means.