Method and apparatus for using multiple filters for enhanced portable navigation

Patent metadata

Field	Value
Publication number	US-10228252-B2
Application number	US-201514831706-A
Country	US
Kind code	B2
Filing date	Aug 20, 2015
Priority date	Sep 3, 2014
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

An apparatus and method are disclosed for enhancing a navigation solution of a portable device and a platform. Motion sensor data may be obtained corresponding to motion of the portable device, such that a first filter may be configured to output a navigation solution and at least one second filter may be configured to use the motion sensor data to generate at least one value. The at least one generated value may then be used with the first filter to enhance the navigation solution output by the first filter.

First claim

What is claimed is:

1. A method for enhancing a navigation solution of a portable device and a platform, wherein the method is operable when the mobility of the device is constrained within the platform and when the mobility of the device is unconstrained within the platform and wherein the device may be tilted to any orientation, the method further comprising:
a) obtaining self-contained motion sensor data corresponding to motion of the portable device;
b) providing a first filter configured to use at least the motion sensor data to generate and output a navigation solution, wherein the first filter is a state estimation technique;
c) providing at least one second filter configured to use at least the motion sensor data to generate at least one value, wherein the at least one second filter is a state estimation technique;
d) generating at least one value with the at least one second filter; and
e) using the at least one generated value as input information to the first filter to enhance the navigation solution output by the first filter.

2. The method of claim 1 , wherein the at least one generated value comprises a heading angle of the portable device and wherein using the at least one generated value comprises performing a dead reckoning calculation using the at least one generated value to provide measurement updates to the first filter for enhancing the navigation solution.

3. The method of claim 2 , wherein the dead reckoning calculation comprises a pedestrian dead reckoning calculation.

4. The method of claim 2 , wherein the dead reckoning calculation comprises a vehicular dead reckoning calculation.

5. The method of claim 2 , wherein the dead reckoning calculation comprises a cycling dead reckoning calculation.

6. The method of claim 2 , wherein using the at least one generated value comprises deriving a platform heading from the portable device heading angle.

7. The method of claim 6 , wherein deriving the platform heading comprises correcting the portable device heading angle with an estimated heading misalignment.

8. The method of claim 1 , wherein the at least one generated value comprises a heading angle of the portable device and wherein using the at least one generated value comprises estimating a heading misalignment of the portable device using the at least one generated value to provide the estimated heading misalignment to the first filter for enhancing the navigation solution.

9. The method of claim 8 , wherein the heading misalignment is estimated from the at least one generated value and a platform heading.

10. The method of claim 9 , wherein the platform heading is derived from a source of absolute navigational information.

11. The method of claim 10 , wherein the source of absolute navigational information comprises a global navigation satellite system (GNSS).

12. The method of claim 1 , wherein the at least one generated value comprises roll and pitch values of the portable device.

13. The method of claim 12 , wherein using the at least one generated value comprises obtaining a transformation between a device frame and a platform frame with the roll and pitch values.

14. The method of claim 13 , wherein transforming the device frame to the platform frame is also based on an estimated heading misalignment of the portable device.

15. The method of claim 14 , wherein the heading misalignment is estimated from the portable device heading angle and a platform heading.

16. The method of claim 14 , wherein the heading misalignment is estimated from a dedicated heading misalignment estimation technique.

17. The method of claim 1 , wherein providing at least one second filter configured to use at least the motion sensor data to generate at least one value and generating at least one value with the at least one second filter reduces problematic double feedback.

18. The method of claim 1 , wherein using the at least one generated value comprises initializing the first filter.

19. The method of claim 18 , wherein the at least one generated value comprises roll and pitch values of the portable device.

20. The method of claim 19 , wherein initializing the first filter occurs during an alignment phase.

21. The method of claim 20 , wherein initializing the first filter transitions the first filter from the alignment phase to a navigation phase.

22. The method of claim 18 , wherein the at least one generated value comprises an initial misalignment between the portable device and the platform.

23. The method of claim 21 , wherein the initial misalignment is derived from a plurality of filters.

24. The method of claim 23 , wherein each of the plurality of filters outputs a candidate initial misalignment and wherein the at least one generated value is selected based at least in part on a comparison of the candidate initial misalignments.

25. The method of claim 24 , wherein the comparison of the candidate initial misalignments uses a source of absolute navigation information.

26. The method of claim 23 , wherein initializing the first filter occurs during an alignment phase.

27. The method of claim 26 , wherein initializing the first filter transitions the first filter from the alignment phase to a navigation phase.

28. The method of claim 1 , further comprising detecting an ambiguity in the navigation solution output by the first filter and running the first filter and the at least one second filter in parallel over a defined time window, wherein using the at least one generated value comprises comparing the at least one generated value to a value output by the first filter during the defined time window to identify one of the filters as providing a more accurate output.

29. The method of claim 28 , wherein the first filter and the at least one second filter are provided with an alternative assumption regarding the detected ambiguity.

30. The method of claim 28 , further comprising providing the at least one generated value to the first filter when the at least one second filter is identified as providing the more accurate output.

31. The method of claim 28 , further comprising comparing outputs of all the filters to identify the filter providing the more accurate output.

32. The method of claim 1 , further comprising any combination of claims 2 , 8 , 12 , 18 , 19 , 22 and/or 28 .

33. A portable device for providing an enhanced navigation solution of the portable device and a platform, wherein the mobility of the device is constrained or unconstrained within the platform and wherein the device may be tilted to any orientation, the portable device comprising:
a) a sensor assembly integrated within the portable device, configured to output data representing motion of the portable device; and
b) a processor operable when the mobility of the device is constrained within the platform and when the mobility of the device is unconstrained within the platform, and wherein the processor is configured to:
i) implement a first filter configured to output a navigation solution, wherein the at least one second filter is a state estimation technique;
ii) implement at least one second filter configured to use the motion sensor data to generate at least one value, wherein the at least one second filter is a state estimation technique; and
iii) use the at least

Assignees

• Trusted Positioning Inc
• Invensense Inc

Inventors

• Georgy Jacques
• Syed Zainab
• Goodall Christopher

Classifications

• G01C21/12

  executed aboard the object being navigated; Dead reckoning · CPC title

• G01C21/165 Primary

  combined with non-inertial navigation instruments · CPC title

• G01S19/38

  Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system · CPC title

• G01C21/20 Primary

  Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence) · CPC title

• G01C21/005

  with correlation of navigation data from several sources, e.g. map or contour matching (G01C21/30 takes precedence) · CPC title