Systems and methods of location and tracking

• US 10,132,917 B2
• Filed: 08/21/2015
• Issued: 11/20/2018
• Est. Priority Date: 02/25/2014
• Status: Active Grant

• Current Assignee: Bridgewest Finance, LLC
• Original Assignee: Bridgewest Finance, LLC
• Inventors: Jalali, Ahmad, Randakrishnan, Dhinakar, Baghaei, Mehran
• Primary Examiner(s): Nguyen, Chuong P
• Application Number:
  US14/832,007
• Publication Number:
  US 20160054429A1
• Time in Patent Office: 1,187 Days
• Field of Search: 342451, 34053913
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/0294 Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering
• CPC Class Codes: G06K 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04W 4/021 Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A position location system is described for determining position of mobile tags attached to assets or people. Zone tags are installed in the venue to assist in position location estimation of mobile Tags. One embodiment describes systems and methods for the zone tags to automatically determine their position location. Another embodiment describes systems and methods to detect that a zone tag has been moved and to determine the new position of the moved zone tags. Another embodiment describes systems and methods whereby mobile tags determine a list of zone tags with which to make range measurement for determining the mobile tag'"'"'s position location.

Claims

1. A system for automatic installation and configuration of zone tags in a position location determination system having mobile tags and zone tags comprising:

the position coordinates of a subset of the zone tags are manually determined, referred to as configured zone tag list, and the remaining zone tags are put in an un-configured list;

for a first zone tag, position server determines list of zone tags which are in close proximity to a first zone tag and whose signals the first zone tag can detect, referred to as a zone tag-proximity-list; and

iteratively;

retrieving the first zone tag from said un-configured list;

making range measurements comprising RTD (round trip delay), between the first un-configured zone tag and the set of configured zone tags in the zone tag-proximity-list of said first zone tag; and

position server verifying if there are enough zone tags in the first zone tag'"'"'s zone tag-proximity-list to make an accurate estimate of the first zone tag'"'"'s position location; and

determining the first un-configured zone tag'"'"'s position using the range measurements, and adding the first zone tag whose position has been determined to the configured zone tag list.

2. A system according to claim 1, wherein to create the zone tag-proximity-list the first zone tag makes signal strength and range measurements comprising round trip delay with at least one access point in the network, and sends the measurements to the position server;

and the

position server makes an estimate of position location of the first zone tag using the reported measurements, and adds those zone tags which are in close proximity to the first zone tag to the first zone tag'"'"'s zone tag-proximity-list.

3. A system according to claim 1, wherein to create the zone tag-proximity-list of the first zone tag the position server puts the zone tags into a discovery phase, where each zone tag sends discovery messages with the zone tags ID;

and the first zone tag searches for discovery messages from other zone tags, and forms the zone tag-proximity-list of said first zone tag by adding the ID of the zone tags whose discovery messages the first zone tag detects.

4. The system of claim 1, whereby the position server creates a list of zone tags whose position location may not be accurately estimated due to lack of adequate number of measurements, reports the list to a system administrator, and the system administrator adds zone tags to the network to provide adequate number of range measurements to make accurate position estimates of the remaining zone tags in the un-configured list.

5. The system according to claim 1 for detecting that zone tags have moved, whereby:

zone tags employ sensors that detect motion; and

the zone tag whose sensor detects movement reports the movement to the position server.

6. The system according to claim 1 for detecting that zone tags have moved, whereby:

each zone tag makes periodic range measurements with at least one zone tag in its zone tag-proximity-list, and sends the measurements to the position sever; and

the position server determines if the zone tag has moved.

7. The system of claim 1, whereby:

each mobile tag makes signal strength and range measurements with at least one access point in the network, and sends the measurements to the position server; and

position server makes an estimate of position location of the mobile tag using the reported measurements, and forms a list of zone tags which are in close proximity to the mobile tag, referred to as the mobile tag'"'"'s tag-zone tag-proximity-list.

8. The system of claim 7, whereby mobile tags make range measurements with the zone tags in the mobile tag'"'"'s tag-zone tag-proximity-list, send the measurements to the position server, and the position server makes an estimate of the mobile tag'"'"'s position location using the range measurements.

9. The system of claim 1, whereby:

the position server puts the zone tags and mobile tags into a discovery phase, where each zone tag sends discovery messages with the zone tag'"'"'s ID; and

mobile tags search for discovery messages from zone tags, and form a list of zone tags whose discovery messages the mobile tag detects, referred to as the mobile tag'"'"'s tag-zone tag-proximity-list.

10. The system of claim 9, whereby mobile tags make range measurements with the zone tags in the mobile tags'"'"' tag-zone tag-proximity-list, send the measurements to the position server, and the position server makes an estimate of the mobile tags'"'"' position location using the range measurements.

11. A process for determining relative location of a zone tag within transmission a local monitoring zone of a wireless network comprising the steps of:

providing a plurality of zone tags comprising configured zone tags whose location is known and an un-configured zone tag whose location is not known, said zone tags having a wireless transceiver configured to communication over said wireless network;

placing the configured zone tags in said local monitoring zone, each of said configured zone tags at a known position and stored on a position server;

placing an un-configured zone tag within said local monitoring zone, said un-configured zone tag communicating wirelessly with said plurality of configured zone tags;

and receiving, by said position server, un-configured zone tag to said configured zone tags communication times and determining a relative position of said un-configured zone tag as a function of said communication times.

12. The process of claim 11 wherein said plurality of zone tags comprises at least three zone tags.

13. The process of claim 11 wherein said un-configured zone tag to said plurality of zone tags wireless communication is triggered by said un-configured zone tag broadcasting a discovery message, said discovery message including said un-configured zone tag'"'"'s identifier.

14. The process of claim 11 wherein said position server generates an alert upon receiving insufficient data to accurately determine said un-configured zone tag position.

15. The process of claim 11 wherein said position server monitors for position changes of said un-configured zone tag.

16. The process of claim 15 further providing a motion sensor coupled with each of said zone tags, wherein said position server receives motion sensor data.

17. The process of claim 15 wherein said position server compares periodic round trip delay or time of arrival measurements with historic round trip delay or time of arrival measurements in order to determine un-configured zone tag movement.

18. The process of claim 15 wherein said position server compares periodic radio signal strength measurements with historic radio signal strength measurements in order to determine un-configured zone tag movement.

19. The process of claim 11 further providing at least one mobile tag, for securing to an asset within said transmission zone, said mobile tag having a wireless transceiver configured to communication over said wireless network;

associating each said mobile tag with at least one of said configured zone tags;

determining relative position of said mobile tag as a function of configured zone tag to mobile tag communication time.

20. The process of claim 19 wherein said mobile tag to said zone tag wireless communication is triggered by said mobile tag broadcasting a discovery message, said discovery message including said mobile tag'"'"'s identifier.