Reducing elevation error with environmental pressure anomaly compensation

Patent metadata

Field	Value
Publication number	US-9823068-B2
Application number	US-201615040996-A
Country	US
Kind code	B2
Filing date	Feb 10, 2016
Priority date	Jun 12, 2012
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A method for determining an environmental pressure change affecting a pressure sensor within a portable device to determine an elevation of the portable device is disclosed. The method involves estimating a location of the mobile device, estimating an atmospheric pressure associated with the mobile device at a server based on data indicative of atmospheric pressure received from the mobile device, and generating the elevation of the mobile device based on the atmospheric pressure associated with the mobile device and reference data indicative of an absolute elevation reference. The absolute elevation determined may be based on the estimated location of the mobile device and elevation data obtained from a reference map.

First claim

What is claimed is:

1. A computer-implemented method for determining an elevation of a mobile device, comprising:
estimating a location of the mobile device;
estimating an atmospheric pressure associated with the mobile device at a server based on data indicative of atmospheric pressure as measured by a pressure sensor within the mobile device; and
generating the elevation of the mobile device based on the atmospheric pressure associated with the mobile device and reference data indicative of an absolute elevation reference,
the absolute elevation determined based on the estimated location of the mobile device and elevation data obtained from a reference map wherein the reference map is generated using terrain elevation data obtained from a plurality of datasets.

2. The method of claim 1 , wherein each of the plurality of datasets have terrain elevation data at a different horizontal resolution.

3. The method of claim 2 , wherein the terrain elevation data is obtained from a first dataset having terrain elevation at a first horizontal resolution and a second dataset having terrain elevation at a second horizontal resolution, the first horizontal resolution being a higher resolution than the second horizontal resolution, each of the first dataset and the second dataset being one of the plurality of datasets.

4. The method of claim 3 , wherein terrain elevation data that is unobtainable from the first dataset is obtained from the second dataset to generate the reference map.

5. The method of claim 1 , wherein the reference map includes reference data indicative of atmospheric pressure associated with a first map tile containing the estimated location of the mobile device, the first map tile being one of a plurality of contiguous map tiles composing the reference map.

6. The method of claim 5 , wherein the reference data indicative of atmospheric pressure associated with the first map tile is subtracted from the data indicative of atmospheric pressure received from the mobile device prior to generating the elevation of the mobile device.

7. The method of claim 5 , wherein the reference data is based, in part, on interpolated pressure data associated with a plurality of stationary pressure sensors located in an area outside of the first map tile that is associated with at least one of the plurality of contiguous map tiles.

8. A computer-implemented method for determining an elevation of a mobile device, the method being executed on a server and comprising:
estimating a location of the mobile device;
determining one or more elevation constraints related to the estimated location of the mobile device;
estimating an atmospheric pressure associated with the mobile device based on data indicative of atmospheric pressure as measured by a pressure sensor within the mobile device; and
generating the elevation of the mobile device using the one or more elevation constraints, and a particle filter to determine a distribution of particles based on the atmospheric pressure associated with the mobile device.

9. The computer-implemented method of claim 8 , wherein the distribution of particles represents a probability distribution of the mobile device's elevation.

10. The computer-implemented method of claim 9 , wherein generating the elevation includes calculating a weighted average over all particles composing the distribution of particles.

11. The computer-implemented method of claim 9 , the method further comprising:
determining an error metric corresponding to the elevation of the mobile device based on the distribution of particles.

12. The computer-implemented method of claim 8 , the method further comprising:
detecting the mobile device has entered a building with a known building model based in part on the estimated location; and
imposing at least one elevation constraint that assigns a higher weight to particles located on one or more floors of the known building model.

13. The computer-implemented method of claim 8 , the method further comprising:
determining whether the mobile device is indoors or outdoors prior to generating the elevation.

14. The computer-implemented method of claim 13 , wherein generating the elevation includes assigning a lower weight to particles located outside of a building when the portable device is determined to be indoors, and assigning a lower weight to particles located inside of a building when the portable device is determined to be outdoors.

15. The computer-implemented method of claim 13 , wherein generating the elevation includes imposing at least one elevation constraint that increases a probability that the elevation of the mobile device is within a predefined distance of a terrain of the estimated location when the mobile device is determined to be outdoors.

16. A computing system for determining an elevation of a mobile device, the computing system comprising:
one or more processors; and
a memory communicatively coupled to the one or more processors, the memory bearing a first set of instructions that when executed on the one or more processors, cause the computing system to:
estimate a location of the mobile device;
determine one or more elevation constraints related to the estimated location of the mobile device;
estimate an atmospheric pressure associated with the mobile device based on data indicative of atmospheric pressure as measured by a pressure sensor within the mobile device; and
generate the elevation of the mobile device based on the atmospheric pressure associated with the mobile device, reference data indicative of an absolute elevation reference, and the one or more elevation constraints,
the absolute elevation reference determined based on the estimated location of the mobile device and elevation data obtained from a reference map, the reference map generated using terrain elevation data obtained from a plurality of datasets.

17. The computing system of claim 16 , wherein the atmospheric pressure associated with the mobile device is further based on reference data indicative of atmospheric pressure associated with a first map tile of the reference map containing the estimated location of the mobile device.

18. The computing system of claim 16 , wherein the data indicative of atmospheric pressure is filtered based on inertial data associated with the mobile device prior to estimating the atmospheric pressure associated with the mobile device.

19. The computing system of claim 18 , wherein the data indicative of atmospheric pressure is further filtered based on correlations between the data indicative of atmospheric pressure and vertical accelerations associated with the mobile device exceeding an acceleration threshold.

Assignees

• Trx Systems Inc

Inventors

• Karvounis John
• Napora Jared
• Hakim Dan
• Teolis Carole
• Miller John Riley
• Funk Benjamin E

Classifications

• G01C5/06 Primary

  by using barometric means · CPC title