Mobile device positioning using modulated light signals and coarse positioning information

Patent metadata

Field	Value
Publication number	US-9857162-B1
Application number	US-201615273006-A
Country	US
Kind code	B1
Filing date	Sep 22, 2016
Priority date	Sep 22, 2016
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

Disclosed are systems and methods for tracking position of a mobile device within a venue. In an aspect, the mobile device obtains a plurality of light source identifiers and a plurality of location identifiers corresponding to a plurality of light sources within the venue, determines a first position of the mobile device within the venue, the first position having a first position accuracy, determines a subset of the plurality of light source identifiers corresponding to a subset of the plurality of light sources based on a location of each light source in the subset of light sources being within a threshold distance of the first position, demodulates a fragment of a light source identifier, and determines a second position of the mobile device based on one or more location identifiers corresponding to the light source, the second position having a greater position accuracy than the first position accuracy.

First claim

What is claimed is:

1. A method for tracking a position of a mobile device within a venue, comprising:
obtaining, by the mobile device, a plurality of light source identifiers and a plurality of location identifiers corresponding to a plurality of light sources within the venue, each light source identifier and each location identifier corresponding to a light source of the plurality of light sources;
determining, by the mobile device, a first position of the mobile device within the venue, the first position having a first position accuracy;
determining, by the mobile device, a subset of the plurality of light source identifiers corresponding to a subset of the plurality of light sources based, at least in part, on a location of each light source in the subset of light sources being within a threshold distance of the first position;
demodulating, by the mobile device, a first fragment of a light source identifier; and
based on the first fragment unambiguously mapping to a first light source identifier within the subset of the plurality of light source identifiers, determining, by the mobile device, a second position of the mobile device based, at least in part, on one or more location identifiers of the plurality of location identifiers corresponding to a first light source of the subset of the plurality of light sources corresponding to the first light source identifier, the second position having a second position accuracy that is greater than the first position accuracy.

2. The method of claim 1 , further comprising:
based on the first fragment ambiguously mapping to the first light source identifier within the subset of the plurality of light source identifiers:
demodulating, by the mobile device, a second fragment of a second light source identifier of a second light source adjacent to the first light source;
matching, by the mobile device, the first fragment to the first light source identifier based on the first light source being adjacent to the second light source and the first fragment matching a fragment of the first light source identifier; and
determining, by the mobile device, the second position of the mobile device based, at least in part, on the one or more location identifiers corresponding to the first light source.

3. The method of claim 2 , wherein the first fragment maps to more than one light source identifier of the subset of the plurality of light source identifiers.

4. The method of claim 1 , wherein the first fragment comprises a number of bits of the first light source identifier that can be demodulated within a threshold period of time.

5. The method of claim 1 , wherein the first light source comprises at least one visible light communication (VLC) light source.

6. The method of claim 1 , wherein the one or more location identifiers corresponding to the first light source comprises location coordinates of the first light source within the venue, dimensions of the first light source, orientation of the first light source, shape of the first light source, or any combination thereof.

7. The method of claim 1 , wherein the threshold distance of the first position of the mobile device is based on the first position accuracy of the first position of the mobile device.

8. The method of claim 1 , wherein the first position is based upon a number of light sources between the first light source and a light source having a location known to the mobile device.

9. The method of claim 7 , wherein the first position is further based upon heading measurements of the mobile device.

10. The method of claim 1 , wherein the first position is based upon personal dead reckoning measurements from a light source of the plurality of light sources having a location known to the mobile device.

11. The method of claim 1 , further comprising:
determining the first light source identifier of the first light source based, at least in part, on a sequence of identifiers of light sources previously detected by the mobile device and a direction of travel of the mobile device in the venue.

12. The method of claim 1 , wherein the obtaining the plurality of light source identifiers and the plurality of location identifiers comprises receiving, at the mobile device, the plurality of light source identifiers and the plurality of location identifiers from a server.

13. The method of claim 1 , wherein determining the second position of the mobile device comprises:
determining the second position of the mobile device based on a position of a fixture containing the first light source, a relative angle to the fixture containing the first light source, an orientation of the mobile device to the fixture containing the first light source, an image of the fixture containing the first light source captured by a camera of the mobile device, or any combination thereof.

14. The method of claim 13 , wherein determining the second position of the mobile device comprises:
determining the second position of the mobile device based on the position of the first light source, a position of a second light source, and a position of at least one other light source in the subset of the plurality of light sources.

15. The method of claim 1 , wherein the first position is based upon measured wireless signals.

16. The method of claim 15 , wherein the measured wireless signals comprise wireless local area network (WLAN) signals, cellular network signals, satellite positioning system (SPS) signals, or any combination thereof.

17. An apparatus for tracking a position of a mobile device within a venue, comprising:
a light sensor;
a transceiver configured to obtain a plurality of light source identifiers and a plurality of location identifiers corresponding to a plurality of light sources within the venue, each light source identifier and each location identifier corresponding to a light source of the plurality of light sources; and
at least one processor configured to:
determine a first position of the mobile device within the venue, the first position having a first position accuracy;
determine a subset of the plurality of light source identifiers corresponding to a subset of the plurality of light sources based, at least in part, on a location of each light source in the subset of light sources being within a threshold distance of the first position;
demodulate a first fragment of a light source identifier detected by the light sensor; and
determine, based on the first fragment unambiguously mapping to a first light source identifier within the subset of the plurality of light source identifiers, a second position of the mobile device based, at least in part, on one or more location identifiers of the plurality of location identifiers corresponding to a first light source of the subset of the plurality of light sources corresponding to the first light source identifier, the second position having a second position accuracy that is greater than the first position accuracy.

18. The apparatus of claim 17 , wherein the at least one processor is further configured to:
based on the first fragment ambiguously mapping to the first light source identifier within the subset of the plurality of light source identifiers:
demodulate a second fragment of a second light source identifier of a second light source adjacent to the first light source;
match the first fragment to the first light source identifier based on the first light source being adjacent to the second light source and the first fragment matching a fragment of the first light source identifier; and
determine the second p

Assignees

• Qualcomm Inc

Inventors

• Gum Arnold
• Ramasamy Bala

Classifications

• G01S2201/01

  adapted for specific applications or environments · CPC title

• G01S1/7034 Primary

  Mounting or deployment thereof · CPC title

• G01C21/206

  specially adapted for indoor navigation · CPC title

• G01S5/16

  using electromagnetic waves other than radio waves · CPC title

• H04W4/029

  Location-based management or tracking services · CPC title