Systems and methods for reducing error detection latency in LPV approaches

• US 8,928,527 B2
• Filed: 03/19/2013
• Issued: 01/06/2015
• Est. Priority Date: 03/19/2013
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: He, Gang, Wyatt, Ivan Sandy
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): GOLDMAN, RICHARD A
• Application Number:
  US13/847,151
• Publication Number:
  US 20140288733A1
• Time in Patent Office: 658 Days
• Field of Search: None
• US Class Current: 342/357.32
• CPC Class Codes: G01C 21/005 with correlation of navigation data from several sources, e.g. map or contour matching G01C21/30 takes precedence
• CPC Class Codes: G01S 19/15 Aircraft landing systems
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• 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
• CPC Class Codes: G08G 5/025 Navigation or guidance aids radar or analogous systems specially adapted for landing purposes G01S13/913

Abstract

Systems and methods for reducing error detection latency in LPV approaches are provided. In certain embodiments, a method for navigational guidance includes calibrating inertial measurements acquired from an inertial navigation system with satellite-based augmentation system position measurements acquired from a satellite-based augmentation system to create corrected inertial navigation system positions. The method also includes determining whether the satellite-based augmentation system experienced a fault when the inertial measurements were calibrated with the satellite-based augmentation system position measurements. Further, when the satellite-based augmentation system did not experience a fault, the method includes monitoring the satellite-based augmentation system navigation position measurements based on the corrected inertial navigation system positions.

Claims

1. An aircraft landing system on an aircraft, the system comprising:

an inertial navigation system configured to make inertial measurements of motion for the aircraft;

a satellite-based augmentation system configured to provide satellite-based augmentation system position measurements of the aircraft; and

a processor configured to receive the inertial measurements from the inertial navigation system and receive the satellite-based augmentation system position measurements from the satellite-based augmentation system, wherein the processor executes instructions that cause the processor to;

calibrate the inertial measurements to the satellite-based augmentation system position measurements;

determine whether the satellite-based augmentation system experienced a fault when the inertial measurements were calibrated with the satellite-based augmentation system position measurements; and

when the satellite-based augmentation system did not experience a fault, monitor the satellite-based augmentation system navigation position measurements based on the calibrated inertial measurements.

2. The aircraft landing system of claim 1, wherein the aircraft is navigated along a localizer performance with vertical guidance approach.

3. The aircraft landing system of claim 1, wherein the processor calibrates the inertial measurements to the satellite-based augmentation system position measurements by:

identifying an aircraft position as a calibration reference point based on the satellite-based augmentation system position measurements;

integrating at least one of inertial velocities and accelerations from the inertial navigation system over a period of time relative to a calibration reference point to identify an integrated inertial navigation system position; and

calculating a time dependent inertial navigation system drift based on the difference between the integrated inertial navigation system position and a corresponding satellite-based augmentation system position measurement.

4. The aircraft landing system of claim 1, wherein the processor interpolates a plurality of calculated inertial navigation system drifts to find an average time dependent difference between a plurality of integrated inertial navigation system positions and a corresponding plurality of satellite-based augmentation system position measurements.

5. The aircraft landing system of claim 1, wherein the processor determines that the satellite-based augmentation system did not experience a fault when the inertial measurements were calibrated by determining that the satellite-based augmentation system did not experience a fault for a period of time greater than a latency period for identifying faults in the satellite-based augmentation system.

6. The aircraft landing system of claim 1, wherein the processor monitors the satellite-based augmentation system navigation position measurements based on the calibrated inertial measurements by:

integrating at least one of inertial velocities and accelerations from the inertial navigation system over a period of time to identify an integrated inertial navigation system position; and

calculating a corrected inertial navigation system position by subtracting an average inertial navigation system drift from the integrated inertial navigation system position.

7. The aircraft landing system of claim 6, wherein the processor further monitors satellite-based augmentation system position measurements of the aircraft based on the calibrated inertial measurements by:

comparing the satellite-based augmentation system position measurements against the corrected inertial navigation system position; and

when the difference between the satellite-based augmentation system position measurements and the corrected inertial navigation system position exceed a threshold, determining that at least one of the inertial navigation system and the satellite-based augmentation system is providing misleading data.

8. The aircraft landing system of claim 7, wherein the aircraft landing system provides alert information to flight crews to determine whether to abort a localizer performance with vertical guidance approach when at least one of the inertial navigation system and the satellite-based augmentation system is providing misleading data.

9. A method for navigational guidance, the method comprising:

calibrating inertial measurements acquired from an inertial navigation system with satellite-based augmentation system position measurements acquired from a satellite-based augmentation system to create corrected inertial navigation system positions;

determining whether the satellite-based augmentation system experienced a fault when the inertial measurements were calibrated with the satellite-based augmentation system position measurements; and

when the satellite-based augmentation system did not experience a fault, monitoring the satellite-based augmentation system navigation position measurements based on the corrected inertial navigation system positions.

10. The method of claim 9, wherein calibrating inertial measurements with satellite-based augmentation system position measurements comprises:

identifying an aircraft position as a calibration reference point based on the satellite-based augmentation system position measurements;

integrating inertial velocities from the inertial navigation system over a period of time to identify an integrated inertial navigation system position; and

calculating an inertial navigation system drift based on the difference between the integrated inertial navigation system position and a corresponding satellite-based augmentation system position measurement.

11. The method of claim 9, wherein determining that the satellite-based augmentation system did not experience a fault when the inertial measurements were calibrated with the satellite-based augmentation system position measurements comprises determining that the satellite-based augmentation system did not experience a fault for a period of time greater than a latency period for identifying faults in the satellite-based augmentation system.

12. The method of claim 9, wherein monitoring the satellite-based augmentation system navigation position measurements based on the calibrated inertial measurements comprises:

integrating inertial velocities from the inertial navigation system over a period of time to identify an integrated inertial navigation system position; and

calculating a corrected inertial navigation system position by subtracting an average inertial navigation system drift from the integrated inertial navigation system position.

13. The method of claim 12, wherein monitoring the satellite-based augmentation system navigation position measurements based on the calibrated inertial measurements further comprises:

determining the difference between the satellite-based augmentation system position measurements and the corrected inertial navigation system position; and

when the difference between the satellite-based augmentation system position measurements and the corrected inertial navigation system position exceed a threshold, determining that at least one of the inertial navigation system and the satellite-based augmentation system is providing misleading data.

14. The method of claim 13, further comprising providing alert information to a flight crew to determine whether to aborting a localizer performance with vertical guidance approach when at least one of the inertial navigation system and the satellite-based augmentation system is providing misleading data.

15. An aircraft landing system on an aircraft, the system comprising:

an inertial navigation system configured to make inertial measurements of motion for the aircraft;

a satellite-based augmentation system configured to provide satellite-based augmentation system position measurements of the aircraft; and

a processor configured to receive the inertial measurements from the inertial navigation system and receive the satellite-based augmentation system position measurements from the satellite-based augmentation system, wherein the processor executes at least one instance of an inertial coasting algorithm, wherein an instance of an inertial coasting algorithm comprises;

a calibration period, wherein the inertial coasting algorithm directs the processor to calibrate the inertial measurements to the satellite-based augmentation system position measurements;

a substantiation period, wherein the inertial coasting algorithm directs the processor to determine whether the calibrated inertial measurements and satellite-based augmentation system position measurements are based on misleading data; and

a monitoring period, wherein the inertial coasting algorithm directs the processor to compare the calibrated inertial measurements and the satellite-based augmentation system position measurements when the calibrated inertial measurements and satellite-based augmentation system position measurements are not based on misleading data.

16. The aircraft landing system of claim 15, wherein the processor executes multiple instances of the inertial coasting algorithm, wherein the execution of each instance of the inertial coasting algorithm is separated by a time interval.

17. The aircraft landing system of claim 16, wherein the time interval between each instance of the inertial coasting algorithm is the same.

18. The aircraft landing system of claim 15, wherein the processor begins executing the at least one instance of the inertial coasting algorithm when the aircraft reaches at least one of:

an altitude in relation to the runway; and

a distance from the runway.

19. The aircraft landing system of claim 15, wherein the inertial coasting algorithm directs the processor to calibrate the inertial measurements with the satellite-based augmentation system position measurements by calculating an average inertial navigation system drift based on an average difference between a plurality of integrated inertial navigation system positions and a corresponding plurality of satellite-based augmentation system position measurements.

20. The aircraft landing system of claim 19, wherein the inertial coasting algorithm directs the processor to enter the substantiation period when the variance for the average inertial navigation system drift is below a variance threshold.