Synthetic pressure altitude determining system and method with wind correction

• US 6,819,983 B1
• Filed: 12/03/2002
• Issued: 11/16/2004
• Est. Priority Date: 12/03/2002
• Status: Expired due to Term

• Current Assignee: Rockwell Collins, Inc. (Rtx Corporation)
• Original Assignee: Rockwell Collins, Inc. (Rtx Corporation)
• Inventors: McGraw, Gary A.
• Primary Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US10/308,422
• Time in Patent Office: 714 Days
• Field of Search: 701/4, 701/7, 701/10, 701/14, 340/945, 340/949, 340/967, 340/968, 340/970, 340/973, 340/974, 340/977
• US Class Current: 701/4
• CPC Class Codes: G01C 5/005 altimeters for aircraft G01C5/02, G01C5/06 take precedence

Abstract

A method of generating a synthetic pressure altitude is disclosed. The method includes providing a static air temperature to a data processing device. The method also includes providing a wind velocity, a ground velocity, and a geometric altitude to the data processing device. Further, the method includes performing a numerical integration based on the static air temperature, the wind velocity, the ground velocity, and the geometric altitude. The wind velocity and the ground velocity are used to estimate pressure gradients not included in a static air column model.

Claims

1. A method of generating a synthetic pressure altitude, comprising:

providing a static air temperature to a data processing device;

providing a wind velocity to the data processing device;

providing a ground velocity to the data processing device;

providing a geometric altitude to the data processing device; and

performing a numerical integration based on the static air temperature, the wind velocity, the ground velocity, and the geometric altitude, the wind velocity and ground velocity used to cancel errors of a static air column model.

2. The method of claim 1, further comprising:

providing an aircraft latitude to the data processing device.

3. The method of claim 1, further comprising:

estimating the wind acceleration using an estimation filter.

4. The method of claim 3, wherein the estimation filter comprises a Kalman filter.

5. The method of claim 4, wherein the Kalman filter is a linear Kalman filter.

6. The method of claim 1, wherein the geometric altitude is generated from a global positioning system (CPS) signal.

7. The method of claim 1, wherein the geometric altitude is generated from an inertial navigation system.

8. The method of claim 1, wherein the wind velocity comprises a cross wind component.

9. The method of claim 1, wherein the wind velocity comprises an along track wind component.

10. The method of claim 1, further comprising:

smoothing the wind velocity data.

11. A method of determining the pressure altitude of an aircraft, comprising:

providing a static air temperature, from a temperature sensor on the aircraft, to a data processing device;

providing a wind velocity, from a flight management system on the aircraft, to the data processing device;

providing a ground velocity, from a flight management system on the aircraft, to the data processing device;

providing a geometric altitude, from a position determining system on the aircraft, to the data processing device; and

performing a numerical integration based on the static air temperature, the wind velocity, the ground velocity, and the geometric altitude, the wind velocity and ground velocity used to cancel errors of a static air column model.

12. The method of claim 11, further comprising:

providing a measured pressure altitude to the data processing device; and

correcting the measured pressure altitude using the output of the numerical integration.

13. The method of claim 11, further comprising:

estimating the wind acceleration using an estimation filter.

14. The method of claim 13, wherein the estimation filter comprises a Kalman filter.

15. The method of claim 14, wherein the Kalman filter is a linear Kalman filter.

16. The method of claim 11, wherein the geometric altitude is generated from a global positioning system (GPS) signal.

17. The method of claim 11, wherein the geometric altitude signal is generated from an inertial navigation system.

18. The method of claim 11, wherein the wind velocity comprises a cross wind component.

19. The method of claim 11, wherein the wind velocity comprises an along track wind component.

20. The method of claim 11, further comprising:

smoothing the wind velocity data.

21. A pressure altitude determining system, comprising:

a data processing device,

an air temperature monitor communicating air temperature data to the data processing device;

a wind velocity monitor communicating wind velocity data to the data processing device;

a ground velocity monitor communicating ground velocity data to the data processing device; and

a geometric altitude monitor communicating geometric altitude data to the data processing device,

wherein the data processing device carries out a numerical integration based on the air temperature data, the wind velocity data, the ground velocity data, and the geometric altitude data, to generate a synthetic pressure altitude.

22. The system of claim 21, further comprising:

an aircraft latitude monitor communicating aircraft latitude data to the data processing device.

23. The system of claim 21, further comprising:

a wind acceleration generator that generates a wind acceleration using a state estimator.

24. The system of claim 23, wherein the estimation filter comprises a Kalman filter.

25. The system of claim 24, wherein the Kalman filter is a linear Kalman filter.

26. The system of claim 21, wherein the geometric altitude is generated from a global positioning system (GPS) signal.

27. The system of claim 21, wherein the geometric altitude signal is generated from an inertial navigation system.

28. The system of claim 21, wherein the wind velocity comprises a cross wind component.

29. The system of claim 21, wherein the wind velocity comprises an along track wind component.

30. The system of claim 21, further comprising:

wind velocity data smoothing algorithm.