HEADING CONSTRAINTS IN A PARTICLE FILTER

• US 20160195391A1
• Filed: 05/15/2015
• Published: 07/07/2016
• Est. Priority Date: 01/06/2015
• Status: Active Grant

• Current Assignee: TRX Systems, Inc.
• Original Assignee: TRX Systems, Inc.
• Inventors: Miller, John, Young, Travis, Karvounis, John, Hakim, Dan, Napora, Jared, Funk, Benjamin, Teolis, Carole
• Granted Patent: US 9,759,561 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: G01S 5/014 Identifying transitions between environments
• CPC Class Codes: G01S 5/015 between indoor and outdoor environments
• CPC Class Codes: G01S 5/0247 Determining attitude
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence

Abstract

A method for computing a correction to a compass heading for a portable device worn or carried by a user is described. The method involves determining a heading for the device based on a compass reading, collecting data from one or more sensors, determining if the device is indoors or outdoors based on the collected data, and correcting the heading based on the determination of whether the device is indoors or outdoors.

Claims

1. A computer implemented method for computing a correction to a compass heading for a portable device worn or carried by a user, comprising:

collecting data from one or more sensors associated with the portable device;

determining with a processor if the portable device is indoors or outdoors based on the collected data; and

automatically correcting a heading for the device based on the determination of whether the portable device is indoors or outdoors.

2. The computer implemented method of claim 1, wherein determining the heading includes using a particle filter to determine a location and heading circle for the device based on at least the compass reading.

3. The computer implemented method of claim 2, wherein the one or more sensors include a light sensor, wherein the data collected from the light sensor includes one or more of light intensity, light type, and light variance, and wherein determining if the portable device is indoors or outdoors includes determining if the portable device has transitioned between indoors and outdoors based on the data collected from the light sensor.

4. The computer implemented method of claim 3, further comprising collecting data from one or more sources unassociated with the portable device, wherein the data collected includes sunset and sunrise information for a location of the portable device, and further comprising enabling the light sensor at a threshold time after sunrise and disabling the light sensor at a threshold time before or after sunset.

5. The computer implemented method of claim 3, wherein the one or more sensors include a proximity sensor, and further comprising disabling the light sensor when data collected from the proximity sensor indicates that the light sensor is obstructed from light and enabling the light sensor when data collected from the proximity sensor indicates that the light sensor is no longer obstructed from light.

6. The computer implemented method of claim 3, wherein correcting the heading 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.

7. The computer implemented method of claim 2, wherein the one or more sensors include a motion tracker providing the location and a magnetometer providing magnetic field readings, and wherein determining if the portable device is indoors or outdoors includes determining magnetic field variance based on the location.

8. The computer implemented method of claim 7, wherein correcting the heading 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.

9. The computer implemented method of claim 2, wherein the one or more sensors includes a GPS system providing signal-to-noise ratio data from one or more high elevation satellites and signal-to-noise ratio data from one or more low elevation satellites, and wherein determining if the portable device is indoors or outdoors includes determining a degradation in the signal-to-noise ratio data from the one or more high elevation satellites.

10. The computer implemented method of claim 9, wherein correcting the heading 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.

11. The computer implemented method of claim 2, wherein the one or more sensors includes a GPS system providing signal-to-noise ratio data from one or more satellites, and wherein determining if the portable device is indoors or outdoors includes determining a variance in an average of the signal-to-noise ratio data.

12. The computer implemented method of claim 11, wherein correcting the heading 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.

13. The computer implemented method of claim 2, wherein the one or more sensors includes a received signal strength indicator providing received signal strength indication (RSSI), and wherein determining if the portable device is indoors or outdoors includes determining a variance in the RSSI over a period of time.

14. The computer implemented method of claim 13, wherein correcting the heading 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 2, further comprising collecting data from one or more sources unassociated with the portable device, wherein the data collected includes an outline of a building near the location of the portable device, further comprising determining a grid of most probable building grid directions based on the outline, and wherein determining if the portable device is indoors or outdoors includes determining that the portable device is moving along a grid direction of the grid over a period of time.

16. The computer implemented method of claim 15, wherein correcting the heading 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.