Method and system for processing pulse signals within an inertial navigation system

• US 20040064252A1
• Filed: 09/26/2002
• Published: 04/01/2004
• Est. Priority Date: 09/26/2002
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Kirkland, Jeffrey, Eckert, Charles
• Granted Patent: US 6,876,926 B2
• Time in Patent Office: Days
• US Class Current: 701/220
• CPC Class Codes: G01C 21/183 Compensation of inertial measurements, e.g. for temperature effects

Abstract

A method and system for processing pulse signals within an inertial device is provided. The inertial device may have inertial sensors, such as accelerometers and gyroscopes. The inertial sensors may output signals representative of a moving body'"'"'s motion. The signals may require correction due to imperfections and other errors of the inertial sensors. The inertial device may receive signals from the inertial sensors and process the signals on a signal-by-signal basis so that when processing the signals, the inertial device at least recognizes which sensor output a signal and when the signal was output. The inertial device may then correlate signals that were output from the inertial sensors at selected times in order to transform the signals into a desired navigational frame of reference.

Claims

1. In an inertial navigation system, a method comprising:

producing a plurality of first and second signals by inertial sensors;

relating a given first signal to a given second signal, wherein the given first signal and the given second signal were produced at substantially the same time period;

processing the given first signal and the given second signal so as to establish a representation of the given first signal and the given second signal; and

outputting the representation of the given first signal and the given second signal.

2. The method of claim 1, wherein producing the plurality of first and second signals by inertial sensors comprises producing rotational and acceleration signals by the inertial sensors.

3. The method of claim 2, wherein relating the given first signal to the given second signal comprises matching a given rotational signal with a given acceleration signal so as to establish a set of rotational and acceleration signals, wherein the set of rotational and acceleration signals comprises rotational and acceleration signals that were produced at substantially the same time.

4. The method of claim 3, wherein processing the given first signal and the given second signal comprises processing the set of rotational and acceleration signals so as to establish a representation of the set of rotational and acceleration signals, thereby reducing coning and sculling errors within the representation of the set of rotational and acceleration signals.

5. The method of claim 1, wherein relating the given first signal to the given second signal comprises matching together a signal produced within a buffer time period of another signal.

6. The method of claim 1, wherein processing the given first signal and the given second signal comprises transforming the given second signal into a frame of reference based on the given first signal.

7. The method of claim 1, wherein the inertial navigation system has been calibrated so as to establish known calibration parameters.

8. The method of claim 7, further comprising independently processing the given first signal and the given second signal using the known calibration parameters so as to establish corrected first and second signals.

9. The method of claim 8, wherein independently processing the given first signal and the given second signal using the known calibration parameters comprises multiplying the given first signal and the given second signal by the known calibration parameters.

10. The method of claim 8, wherein independently processing the given first signal and the given second signal comprises correcting the given first signal and the given second signal for errors selected from the group consisting of scaling factor errors, bias errors, and asymmetry errors.

11. In an inertial navigation system that has been calibrated so as to establish known calibration parameters, a method comprising:

receiving a plurality of pulse signals from a known inertial sensor;

upon reception of each individual pulse signal of the plurality of pulse signals, processing each pulse signal using the known calibration parameters so as to establish individually corrected pulse signals;

accumulating the individually corrected pulse signals so as to establish respective groups of signals;

processing each respective group of signals so as to establish a representation of the plurality of pulse signals from the known inertial sensor; and

outputting an indication of the representation of the plurality of pulse signals.

12. The method of claim 11, wherein processing each pulse signal using the known calibration parameters so as to establish the individually corrected pulse signals comprises processing each signal of the plurality of signals independent of each other.

13. The method of claim 11, wherein accumulating the individually corrected pulse signals so as to establish the respective groups of signals comprises relating a given first signal of the corrected pulse signals to a given second signal of the corrected pulse signals, wherein the given first signal and the given second signal were produced at substantially the same time period.

14. The method of claim 11, wherein outputting the indication of the representation of the plurality of pulse signals comprises outputting information selected from the group consisting of a yaw, a pitch, and a roll rotation of the inertial navigation system.

15. The method of claim 11, wherein processing each group of signals so as to establish the representation of the plurality of pulse signals comprises establishing a Quaternion output.

16. The method of claim 15, wherein establishing the Quaternion output comprises forming a direction cosine matrix (DCM) with the respective groups of signals.

17. The method of claim 15, wherein establishing the Quaternion output comprises transforming a frame of reference of the respective groups of signals.

18. The method of claim 15, wherein establishing the Quaternion output comprises determining a set of Euler angles.

19. The method of claim 18, wherein determining the set of Euler angles comprises determining a yaw, a pitch, and a roll rotation of the inertial navigation system.

20. A navigation system comprising:

a plurality of inertial sensors operable to output a plurality of pulse signals; and

a processor coupled to the plurality of inertial sensors, the processor operable to receive the plurality of pulse signals,

wherein upon reception of each individual pulse signal of the plurality of pulse signals, the processor individually processes each pulse signal of the plurality of pulse signals using predetermined calibration parameters so as to establish individually corrected pulse signals, and wherein the processor processes the individually corrected pulse signals so as to establish a representation of the plurality of pulse signals from the plurality of inertial sensors.

21. The navigation system of claim 20, wherein the processor relates each of the plurality of pulse signals with at least one of the plurality of inertial sensors.

22. The navigation system of claim 20, wherein the at least one inertial sensor is a sensor selected from the group consisting of a gyroscope and an accelerometer.

23. The navigation system of claim 20, wherein the processor comprises a field programmable gate array (FPGA).

24. The navigation system of claim 20, wherein the processor processes the individually corrected pulse signals by placing the individually correct pulse signals into groups of signals and processing the groups of signals.

25. The navigation system of claim 20, wherein the representation of the plurality of pulse signals from the at least one inertial sensor is selected from the group consisting of a yaw of the system, a pitch of the system, a roll rotation of the system, a Quaternion output, and a set of Euler angles.

26. The navigation system of claim 20, wherein the processor comprises:

a compensator being operable to individually process each pulse signal of the plurality of pulse signals using the predetermined calibration parameters so as to establish the individually to corrected pulse signals;

an accumulator coupled to the compensator, the accumulator being operable to collect the individually corrected pulse signals so as to establish groups of signals; and

an integrator coupled to the accumulator, the integrator being operable to process the groups of signals so as to establish the representation of the plurality of pulse signals from the plurality of inertial sensors.

27. The navigation system of claim 26, wherein the compensator individually processes each pulse signal of the plurality of pulse signals independent of each other.

28. In a navigation system having a plurality of inertial sensors operable to output a plurality of pulse signals, a processor comprising:

a compensator coupled to the plurality of inertial sensors, the compensator operable to receive the plurality of pulse signals and to calibrate the plurality of pulse signals so as to establish calibrated pulse signals;

an accumulator coupled to the compensator, the accumulator operable to correlate signals within the calibrated pulse signals that were output from the plurality of inertial sensors at substantially the same time; and

an integrator coupled to the accumulator, the integrator operable to process the correlated signals so as to transform the correlated signals into a navigational frame of reference.

29. The processor of claim 28, wherein the accumulator matches a rotational signal from the calibrated pulse signals with an acceleration signal from the calibrated pulse signals, wherein the rotational signal and the acceleration signal were output from the plurality of inertial sensors at substantially the same time.

30. The processor of claim 29, wherein the integrator transforms the acceleration signal into the navigational frame of reference of the navigation system at a time reference when one of the plurality of inertial sensors output the rotational signal.

31. The processor of claim 28, wherein the integrator processes the correlated signals to produce navigational parameters selected from the group consisting of position, velocity, heading, and attitude parameters of the navigation system.

32. The processor of claim 28, wherein the processor executes machine language instructions to perform functions of the compensator, the accumulator, and the integrator.