Location Detection

• US 20100214068A1
• Filed: 12/31/2009
• Published: 08/26/2010
• Est. Priority Date: 02/23/2009
• Status: Active Grant

• Current Assignee: Numera, Inc. (Innova Pure Water Incorporated)
• Original Assignee: Wellcore Corporation
• Inventors: Nadkarni, Vijay
• Granted Patent: US 8,558,666 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• CPC Class Codes: G01S 15/876 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S15/872 takes precedence
• CPC Class Codes: G01S 5/22 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/28 takes precedence
• CPC Class Codes: H04Q 2213/13003 Constructional details of switching devices
• CPC Class Codes: H04Q 2213/13095 PIN / Access code, authentication

Abstract

Methods and systems for location detection are disclosed. One method includes a plurality of base stations of a location system obtaining information about at least one tag associated with the location system. One of the plurality of base stations is designated as a master base station for each tag. Each master base station electro-magnetically transmits beacons to each tag that the master base station has been designated as the master of. Each tag responds to the electro-magnetically transmitted beacons with an acoustic signal that identifies the tag. Multiple of the plurality of base stations, receive the acoustic signal of each tag. A location of each tag is estimated based on times of arrival of each acoustic signal of each tag at each of the multiple base stations, and based on location information of each of the multiple base stations.

Claims

1. A method of location detection, comprising:

a plurality of base stations of a location system obtaining information about at least one tag associated with the location system;

designating one of the plurality of base stations as a master base station for each tag;

each master base station electro-magnetically transmitting beacons to each tag that the master base station has been designated master;

each tag responding to the electro-magnetically transmitted beacons with an acoustic signal that identifies the tag;

multiple of the plurality of base stations receiving the acoustic signal of each tag;

estimating a location of each tag based on times of arrival of each acoustic signal of each tag at each of the multiple base stations, and based on location information of each of the multiple base stations.

2. The method of claim 1, wherein designating one of the plurality of base stations as a master base station for each tag comprises:

determining which of the plurality of base stations has a closest proximity to each tag; and

periodically updating which one of the plurality of base stations is the master base station.

3. The method of claim 1, wherein each master base station deterministically times transmissions of the beacons.

4. The method of claim 3, wherein each master base station periodically transmits the beacons.

5. The method of claim 4, further comprising each master base station periodically transmitting beacons to a plurality of tags.

6. The method of claim 5, wherein the master base station separates in time transmission of beacons to each of different tags.

7. The method of claim 4, further comprising controlling a period of the periodically transmitted beacons based on a desired resolution of motion of the tags.

8. The method of claim 1, further comprising monitoring and logging motion of the tags.

9. The method of claim 5, further comprising controlling a period of the periodically transmitted beacons based on a number of tags the master base station is transmitting the beacons to.

10. The method of claim 5, further comprising controlling a period of the periodically transmitted beacons for each tag based on a detected power level of a battery of the tag.

11. The method of claim 1, wherein each beacon is coded for a particular tag.

12. The method of claim 1, wherein the plurality of base stations obtaining information about the at least one tag comprises:

the at least one tag transmitting a registration;

at least one base station receiving the registration and authenticating the at least one tag;

if authenticated, designating a master base station for the at least one tag;

the master base station electromagnetically transmitting an acknowledgement handshake to the at least one tag.

13. The method of claim 1, wherein designating one of the plurality of base stations as the master base station comprises:

identifying which of the plurality of base stations has a best quality combination of acoustic link and electromagnetic link to the tag.

14. The method of claim 1, wherein each of the plurality of base stations occupy a substantially different horizontal plane than the other of the plurality of base stations.

15. The method of claim 1, wherein the base station are interconnected by a backhaul connection, and controlled by a central server.

16. The method of claim 1, wherein the plurality of base station are synchronized, and the location of each tag is estimated by comparing times of arrival of the acoustic signal with known relative locations of each of the plurality of base stations.

17. A method of location detection, comprising:

a tag emitting an acoustic signal, wherein the acoustic signal includes coded information that identifies the tag;

a plurality of base stations receiving the acoustic signal, wherein clocks of the plurality of base stations are synchronized through electromagnetic transmission between the plurality of base stations;

each base station time stamping an arrival time of the acoustic signal;

designating one of the plurality of base stations as a master base station for the tag;

the master base station managing estimating a location of the tag based on the times of arrival of the acoustic signal at each of the multiple base stations, and based on location information of each of the multiple base stations.

18. The method of claim 17, wherein the location information includes each of the plurality of base stations having a priori knowledge of its location relative to other of the plurality of base stations, and relative to confines in which the plurality of base stations are mounted.

19. The method of claim 17, further comprising each tag periodically transmitting the acoustic signals, wherein a period of the periodically transmitted acoustics signals for each tag is based on a detected power level of a battery of the tag.

20. The method of claim 17, further comprising each tag periodically transmitting the acoustic signals, wherein a period of the periodically transmitted acoustics signals for each tag is based on a detected level of motion of the tag.

21. A location determination wireless system, comprising:

a plurality of base stations;

at least one tag, the at least one tag providing the plurality of base stations with information about the at least one tag;

designating one of the plurality of base stations as a master base station for each of the at least one tag;

each master base station electro-magnetically transmitting beacons to each tag that the master base station has been designated master;

each tag responding to the electro-magnetically transmitted beacons with an acoustic signal that identifies the tag;

multiple of the plurality of base stations receiving the acoustic signal of each tag;

estimating a location of each tag based on times of arrival of each acoustic signal of each tag at each of the multiple base stations, and based on location information of each of the multiple base stations.

22. A method of operating a base station within a location determination system, comprising:

at least one of the base station or another base station receiving a registration from a tag;

the base station being designated a master base station;

the base station transmitting beacons to the tag at a determined rate;

the base station and other base stations receiving an acoustic signal from the tag;

the base station in conjunction with the other base stations estimating a location of the tag based on times of arrival of the acoustic signal at the base station and the other base stations.