Mobile device utilizing time of flight for personal security and localization

• US 10,241,194 B2
• Filed: 04/11/2018
• Issued: 03/26/2019
• Est. Priority Date: 03/31/2016
• Status: Active Grant

• Current Assignee: Voll, Inc.
• Original Assignee: Voll, Inc.
• Inventors: Bietz, Steven Lee, Courier, Clinton
• Primary Examiner(s): Taylor, Nathan S
• Application Number:
  US15/950,678
• Publication Number:
  US 20180231634A1
• Time in Patent Office: 349 Days
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: G01S 1/802 the synchronised signals being frequency modulations on carrier waves and the transit times being compared by measuring difference of instantaneous frequencies of received carrier waves
• CPC Class Codes: G01S 1/82 Rotating or oscillating beam beacons defining directions in the plane of rotation or oscillation
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 2205/03 Airborne
• CPC Class Codes: G01S 5/013 Identifying areas in a building
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G01S 5/186 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49
• CPC Class Codes: G01S 5/20 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: G01S 5/28 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H04B 1/385 Transceivers carried on the body, e.g. in helmets
• CPC Class Codes: H04B 1/3877 Arrangements for enabling portable transceivers to be used in a fixed position, e.g. cradles or boosters
• CPC Class Codes: H04B 1/3888 Arrangements for carrying or protecting transceivers
• 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 4/025 using location based information parameters
• 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 56/001 : Synchronization between nodes
• CPC Class Codes: H04W 56/0025 : synchronizing potentially movable access points
• CPC Class Codes: H04W 56/0035 : detecting errors in frequency or phase
• CPC Class Codes: H04W 64/00 : Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/006 : with additional information processing, e.g. for direction or speed determination

Abstract

A method for determining the location of a frequency receiver device with respect to at least two frequency originator devices, each of a current location, the method including synchronizing a clock of the frequency receiver device with a clock of one of the at least two frequency originator devices; receiving by the frequency receiver device, a message including an identification code configured for identifying one of the at least two frequency originator devices and obtaining a broadcast time and a current location of the one of the at least two frequency originator devices by looking up a table correlating the at least two frequency originator devices and their respective broadcast times and current locations; calculating a time of flight of the message by calculating the difference between a receive time at which the message is received by the frequency receiver device and the broadcast time.

Claims

1. A method for determining the location of a frequency receiver device with respect to at least two frequency originator devices, each of a current location, said method comprising:

(a) synchronizing a clock of said frequency receiver device with a clock of one of said at least two frequency originator devices;

(b) receiving by said frequency receiver device, a message comprising an identification code configured for identifying one of the at least two frequency originator devices and obtaining a broadcast time and a current location of said one of the at least two frequency originator devices by looking up a table correlating the at least two frequency originator devices and their respective broadcast times and current locations;

(c) calculating a time of flight of said message by calculating the difference between a receive time at which said message is received by said frequency receiver device and said broadcast time;

(d) repeating steps (a)-(c) for another one of the at least two frequency originator devices to result in a first time of flight and a second time of flight;

(e) calculating a ratio of said first time of flight and said second time of flight;

(f) resolving possible locations of said frequency receiver device by looking up a table containing possible locations of said frequency receiver device with respect to said current locations of the at least two frequency originator devices based on said ratio; and

(g) applying at least one limit to said possible locations to select one of said possible locations with high certainty.

2. The method of claim 1, wherein at least one of said frequency receiver device and the at least two frequency originator devices is a mobile device.

3. The method of claim 1, wherein said frequency receiver device and the at least two frequency originator devices are capable of underwater operation.

4. The method of claim 1, wherein the current location of said one of the at least two frequency originator devices is movable.

5. A method for determining the location of a frequency receiver device with respect to at least two frequency originator devices, each of a known location, said method comprising:

(a) synchronizing a clock of said frequency receiver device with a clock of one of said at least two frequency originator devices;

(b) receiving by said frequency receiver device, a message containing a broadcast time at which said message is broadcasted from said one of said at least two frequency originator devices;

(c) calculating a time of flight of said message by calculating the difference between a receive time at which said message is received by said frequency receiver device and said broadcast time;

(d) repeating steps (a)-(c) for another one of said at least two frequency originator devices to result in a first time of flight and a second time of flight;

(e) calculating a ratio of said first time of flight and said second time of flight;

(f) resolving possible locations of said frequency receiver device by looking up a table containing possible locations of said frequency receiver device with respect to the locations of said at least two frequency originator devices; and

(g) applying at least one limit to said possible locations to select one of said possible locations with high certainty.

6. The method of claim 5, wherein at least one of said frequency receiver device and said at least two frequency originator devices is a mobile device.

7. The method of claim 5, wherein said frequency receiver device and said at least two frequency originator devices are capable of underwater operation.

8. The method of claim 5, wherein each of the known locations is movable.

9. A method for determining the location of a frequency originator device in a system having a frequency receiver device and the frequency originator device, said method comprising:

(a) broadcasting a first message from a master frequency originator device, wherein said first message comprises a first identification code indicating the source of its broadcaster;

(b) upon receiving said first message in the frequency receiver device, looking up a list of frequency originator devices associated with said first identification code from a first table correlating master frequency originator devices and their associated frequency originator devices based on said first identification code and caching a first value associated with a counter of each frequency originator device of said list of frequency originator devices in the frequency receiver device, wherein each frequency originator device of said list comprises a second identification code;

(c) upon receiving said first message in the frequency originator device, broadcasting a second message from the frequency originator device, said second message comprises an identification code selected from said second identification codes of said list of frequency originator devices;

(d) upon receiving said second message in the frequency receiver device, caching a second value of the counter associated with the frequency originator device as identified by said second identification code of said second message; and

(e) determining the location of the frequency originator device by looking up a location from a second table correlating locations of a frequency originator device and counter values associated with the frequency originator device, based on the difference between said second value and said first value.

10. The method of claim 9, wherein said master frequency originator device is also the frequency originator device.

11. The method of claim 9, wherein at least one of the frequency originator device and the frequency receiver device is movable.

12. The method of claim 9, wherein at least one of said frequency receiver device and the frequency originator device is a mobile device.