3D Location Based on Wireless Time of Flight Calculation

• US 20150119077A1
• Filed: 12/29/2014
• Published: 04/30/2015
• Est. Priority Date: 11/15/2012
• Status: Active Grant

• Current Assignee: HID Global Corporation (Assa Abloy AB)
• Original Assignee: Ssi America Inc. (Assa Abloy AB)
• Inventors: BUCHHEIM, James, Hennig, Arne
• Granted Patent: US 9,232,357 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• 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 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

A method and system for indoor location of a mobile device, including: a server, the server adapted to calculate a position of a mobile device within a predefined area; a Master Beacon including: a first radio communications capability, a second radio communications capability, and a master processor, adapted to send data relating to the scan request packets via the second radio communications capability to the server, the data being sent together with a time stamp reflecting a time of receiving the scan request packets; and a plurality of Slave Beacons, each including: the first radio communications capability, a slave processor, adapted to send data relating to the scan request packets to the server, together with a time stamp; the server is adapted to calculate a respective distance of each the beacons from the mobile device.

Claims

1. An indoor location system, comprising:

(a) a server, said server adapted to calculate a position of a mobile device within a predefined area;

(b) a Master Beacon including;

(i) a first radio communications capability, over which said master beacons is adapted to periodically broadcast advertising packets and to capture scan request packets broadcast from a mobile device,

(ii) a second radio communications capability, over which said master beacon is adapted to transmit data packets to said server and receive data packets from said server, and

(iii) a master processor, adapted to send data relating to said scan request packets via said second radio communications capability to said server, said data being sent together with a time stamp reflecting a time of receiving said scan request packets; and

(c) a plurality of Slave Beacons, each said slave beacon including;

(i) said first radio communications capability, adapted to capture said advertising packets and said scan request packets, and to transmit data packets,

(ii) a slave processor, adapted to send data relating to said scan request packets to said server, said data being sent together with a time stamp reflecting a time of receiving said scan request packets;

said server is adapted to calculate a respective distance of each said beacons from said mobile device.

2. The system of claim 1, wherein said respective distances are calculated based on a respective Time of Flight (ToF) value of a signal traveling between each of said beacons and said mobile device.

3. The system of claim 1, wherein said server is further adapted to calculate a location of said mobile device, based on said respective distances.

4. The system of claim 1, wherein said master beacon is operationally coupled to, or integrated in, said server.

5. The system of claim 1, where said slave beacons are adapted to send said data to said server via said master beacon.

6. The system of claim 1, wherein each of said plurality of slave beacons further includes said second radio communications capability.

7. The system of claim 1, wherein said server is a local server.

8. The system of claim 1, wherein said server is a remote server.

9. The system of claim 1, wherein said master beacon is further adapted to send a time stamp value, via said first radio communications capability, to said plurality of slave beacons and said slave beacons are adapted to synchronize with said master beacon based on said time stamp value.

10. The system of claim 9, wherein said synchronization is effected based on said time stamp coupled with a respective known time delay of signal propagation from said master beacon to each of said plurality of slave beacons.

11. The system of claim 2, wherein said slave processor is further adapted to measure said respective Time of Flight (ToF) values of said signal traveling between each of said slave beacons and said mobile device.

12. The system of claim 2, wherein said master processor is further adapted to measure said Time of Flight (ToF) value of said signal traveling between said master beacon and said mobile device.

13. A method for calculating indoor location, comprising the steps of:

(a) providing a system of claim 1;

(b) broadcasting an advertising packet from said master beacon;

(c) receiving a scan request packet, in response to said advertising packet, at said master beacon and said slave beacons;

(d) calculating a respective Time of Flight (ToF) value for a signal traveling between said mobile device and each of said beacons, based on said scan response packet;

(e) calculating a position of said mobile device based on said respective ToF values.

14. The method of claim 13, wherein said ToF values are further calculated based on respective time stamps related to said scan response packet being received at each of said beacons.

15. The method of claim 13, further comprising the step of sending said calculated position of said mobile device, to said mobile device.