(12) Ulllted States Patent
`Perkins et al.
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 8,457,656 B2
`Jun. 4, 2013
`
`US008457656B2
`
`(54) WIRELESS TRACKING SYSTEM AND
`METHOD UTILIZING MULTIPLE LOCATION
`ALGORITHMS
`
`_
`_
`(75) Inventors: Matthew R. PerkIns, San Diego, CA
`(US); Wei Geng, San Diego, CA (US)
`
`(73) Assignee: AWarepoint Corporation, San Diego,
`CA S
`(U )
`
`_
`( * ) Notice:
`
`_
`_
`_
`_
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U_S_C_ 154(b) by 0 day,
`
`(21) Appl. N0.: 13/244,257
`(22) Filed:
`Sep. 23, 2011
`
`(65)
`
`_
`_
`_
`Pm" Pubhcatlo“ Data
`US 2012/0077514 A1
`Mar. 29, 2012
`
`Related US. Application Data
`(60) Provisional application No. 61/386,601, ?led on Sep.
`27’ 2010'
`
`51
`
`(2009.01)
`(2006.01)
`
`Int. C].
`H04W24/00
`G08B 21/00
`(52) us CL
`USPC ................................... .. 455/4561; 340/6866
`(58) Field of Classi?cation Search
`USpC
`455/4561’ 434’ 140’ 4142’ 7; 340/6866’
`34063926’ 81, 101, 5721’ 53912; 342/464;
`204/403_01
`See application ?le for Complete Search history
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`5,732,401 A
`3/1998 Conway
`5,812,865 A
`9/1998 Theimeretal.
`5,977,913 A 11/1999 Christ
`
`7,123,149 B2 10/2006 Nowak etal.
`g;
`i?ymentet a1~
`,
`,
`campora
`7,312,752 B2 12/2007 Smith et al.
`7,324,824 B2
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`7,466,985 B1
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`7,504,928 B2
`3/2009 Nierenberg et a1.
`7,545,326 B2
`6/2009 Caliri et al.
`
`7,580,729 B2
`7,6605 59 B2
`7,688,762 B2
`2005/0021369 A1
`2006/0055552 A1
`
`8/2009 Ozluturk
`2/2010 Hersovieh et a1,
`3/2010 Douglas et al.
`1/2005 Cohen @1711.
`3/2006 Chung et al.
`(Continued)
`OTHER PUBLICATIONS
`
`International Search Report and Written Opinion for PCT Applica
`tion N0. PCT/US2010/049413.
`
`Primary Examiner * Kiet Doan
`(74) Attorney, Agent, or Firm * Clause Eight IPS; Michael
`Catama
`(57)
`
`ABSTRACT
`
`e resent invention rov1 es a so ut1on to m1sta en oca
`Th p
`'
`'
`p
`'d
`l
`'
`'
`k l
`tion calculations based on multipath effects. The present
`invention determines a real-time location of an object in a
`facility using a combination of location algorithms, With a
`signal Characteristic for a Wireless signal from a Communica
`tion device attached to the object received at a sensor of a
`mesh network. The location algorithms preferably include at
`least IWO Of a proximity algorithm, a radial basis function
`algorithm, a maximum likelihood algorithm, a genetic algo
`rithm, a minimum mean squared error algorithm, a radiofre
`quency ?ngerprinting algorithm, a multilateration algorithm,
`a time difference of arrival algorithm, a signal strength algo
`rithm, a time of arrival algorithm, an angle of arrival algo
`rithm, a spatial diversity algorithm, and a nearest neighbor
`algorithm.
`
`12 Claims, 10 Drawing Sheets
`
`0001
`
`Ossia, Inc.
`Exhibit 1006
`PGR2016-00023
`U.S. Patent No. 9,124,125
`
`

`
`US 8,457,656 B2
`Page 2
`
`US. PATENT DOCUMENTS
`3/2006
`2006/0056363 A1
`Ratiu et a1.
`2007/0194944 A1*
`8/2007
`Galera et a1. ............. .. 340/686.6
`1/2008
`2008/0012767 A1
`Caliri et a1.
`3/2008
`2008/0068267 A1
`Huseth et a1.
`4/2008
`2008/0081608 A1
`Findikli et a1.
`2008/0122696 A1*
`5/2008
`Huseth et a1. ............... .. 342/464
`
`2008/0133127 A1
`2008/0214203 A1*
`2009/0067333 A1
`2009/0069642 A1
`2009/0190441 A1*
`2009/0213730 A1
`
`6/2008
`9/2008
`3/2009
`3/2009
`7/2009
`8/2009
`
`Havens
`Titli et a1. ................ .. 455/456.1
`Ergen et a1.
`Gao et a1.
`Zhao et a1. .................. .. 367/128
`Zeng et a1.
`
`* cited by examiner
`
`0002
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 1 0f 10
`
`US 8,457,656 B2
`
`65
`
`FIG. 1
`
`0003
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 2 0f 10
`
`US 8,457,656 B2
`
`55a
`
`60b
`
`75a
`
`b 0 0 .1
`
`b 5 5
`
`a 5 00
`
`FIG. 2
`
`FIG. 2A
`
`FIG. 2B
`
`0004
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 3 0f 10
`
`US 8,457,656 B2
`
`8 a
`
`b 55n
`
`90b
`
`v
`
`55f
`
`56
`
`55m
`
`95
`
`550
`
`856
`
`FIG. 3
`
`0005
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 4 0f 10
`
`US 8,457,656 B2
`
`75 \’
`
`100a
`
`60a
`55a U H
`@
`L
`
`| 7
`
`55b
`6
`
`0 O
`
`= O
`
`77 \,
`
`75b \,
`
`55%
`
`60, 6
`
`FIG. 4
`
`0006
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 5 0f 10
`
`US 8,457,656 B2
`
`1000
`
`/
`
`Transmitting a wireless signal from ?rst
`1001 \f‘ communication device associated with an
`object
`
`1002 \f
`
`Receiving the wireless signal at a ?rst
`sensor
`
`1
`i
`1
`1
`1
`
`1
`
`Transmitting the wireless signal to a ?rst
`1003 \/
`location engine
`
`1004 \/
`
`Transmitting the wireless signal to a
`second location engine
`
`Calculating a location from the wireless
`signal utilizing a ?rst location algorithm
`
`Calculating a location from the wireless
`1006 \/ signal utilizing a second location
`algorithm
`
`1007 \/ Determining a real-time location of the
`object using the location algorithms
`
`FIG. 5
`
`0007
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 6 6f 10
`
`US 8,457,656 B2
`
`2001 \f
`
`Receiving the wireless signal at a ?rst
`sensor
`
`2000
`
`/
`
`Transmitting a signal characteristic of the
`2002 \/
`wireless signal to a location engine
`
`2003 \/ Inputting the signal characteristic into an
`algorithm at the location engine
`
`i
`1
`1
`1
`
`2004 \/ Determining which sub-algorithm to use
`for the signal characteristic
`
`2005 \_/- Determining a real-time location of the
`object using the sub-algorithm
`
`FIG. 6
`
`0008
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 7 0f 10
`
`US 8,457,656 B2
`
`107
`
`1 03
`N
`
`Wireless Network
`
`Interface —<]
`
`Microcontroller
`
`Power Supply
`
`FIG. 7
`
`0009
`
`

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`US. Patent
`
`Jun. 4, 2013
`
`Sheet 8 0f 10
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`US 8,457,656 B2
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`207
`
`I 203
`N
`
`LED
`
`60a
`
`Microcontroller
`
`Power Supply
`
`FIG. 8
`
`0010
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 9 0f 10
`
`US 8,457,656 B2
`
`307
`
`| 303
`N
`
`Speaker
`
`60b
`
`Microcontroller
`
`Power Supply
`
`FIG. 9
`
`0011
`
`

`
`US. Patent
`
`Jun. 4, 2013
`
`Sheet 10 0f 10
`
`US 8,457,656 B2
`
`60c
`\
`
`407
`
`__________________________________ _ _ 11-). _ -l
`
`l
`:
`
`|
`401 I
`
`M
`:
`
`I 403
`/"\_J
`
`_
`
`Magnetlc Energy
`Generator
`
`|
`|
`|
`|
`|
`|
`|
`|
`
`:
`i
`
`|
`|
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`
`Microcontroller
`
`Power Supply
`
`FIG. 10
`
`0012
`
`

`
`US 8,457,656 B2
`
`1
`WIRELESS TRACKING SYSTEM AND
`METHOD UTILIZING MULTIPLE LOCATION
`ALGORITHMS
`
`CROSS REFERENCES TO RELATED
`APPLICATIONS
`
`The Present application claims priority to US. Provisional
`Patent Application No. 61/386,601, ?led on Sep. 27, 2010,
`Which is hereby incorporated by reference in its entirety.
`
`10
`
`STATEMENT REGARDING FEDERALLY
`SPONSORED RESEARCH OR DEVELOPMENT
`
`Not Applicable
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention is related to Wireless tracking sys
`tems and methods. More speci?cally, the present invention
`relates to a system and method for determining a real-time
`location of an object utilizing multiple location algorithms.
`2. Description of the Related Art
`The ability to quickly determine the location of objects
`located Within a facility is becoming a necessity of life. To the
`uninformed observer, the placement of transponders, also
`knoWn as tags, on numerous non-stationary objects Whether
`in an of?ce or home Would appear to be an unnecessary use of
`resources. HoWever, the uninformed observer fails to appre
`ciate the complexity of modern life and the desire for e?i
`ciency, Whether at the o?ice or home.
`For example, in a typical hospital there are numerous shifts
`of employees utiliZing the same equipment. When a neW shift
`arrives, the ability to quickly locate medical equipment not
`only results in a more e?icient use of resources, but also can
`result in averting a medical emergency. Thus, the tracking of
`medical equipment in a hospital is becoming a standard prac
`tice.
`The tracking of objects in other facilities is rapidly becom
`ing a means of achieving greater ef?ciency. A typical radio
`frequency identi?cation system includes at least multiple
`tagged objects each of Which transmits a signal, multiple
`receivers for receiving the transmissions from the tagged
`objects, and a processing means for analyZing the transmis
`sions to determine the locations of the tagged objects Within
`a predetermined environment. The tags can also receive sig
`nals.
`Several prior art references discloses various tracking sys
`tems.
`McKee et al., US. Pat. No. 6,915,135 discloses a system
`for determining presence, identity and duration of presence in
`a given area (a table in a restaurant) of an object (tag attached
`to a Waiter).
`Lester, US. Pat. No. 3,805,265 discloses a location system
`that uses line-of-sight radiant Wave energy for signal trans
`mission.
`SchWengler US. Pat. No. 7,050,819, is directed at the
`problem of adequate poWer for a mobile telephone for a
`tWo-Way communication function or a regeneration function
`as a node of a mesh netWork.
`Christ, US. Pat. No. 5,977,913, discloses a radiofrequency
`system that is utiliZed Within a prison and alloWs for an
`individual to be located after an alarm is triggered by the
`individual.
`Zodnik, US. Patent Publication Number 2004/0147232,
`discloses Wall-mounted (RI-11 or RJ-45) Wireless transceiv
`
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`2
`ers con?gured to only track the location of a self-identi?ed
`Wireless communication device in order to communicate the
`location of the self-identi?ed Wireless communication device
`to an emergency service such as 911.
`One exemplary method triangulates the strongest received
`signals to determine the location of a tagged object. This
`method is based on the assumption that the receivers With the
`strongest received signals are the ones located closest to the
`tagged object. HoWever, such an assumption is sometimes
`erroneous due to common environmental obstacles. Multi
`path effects can result in a further located receiver having a
`stronger received signal from a tagged object than a more
`proximate receiver to the tagged object, Which can result in a
`mistaken location determination. The prior art has disclosed
`various means for overcoming multipath effects.
`Tekinay, US. Pat. No. 6,259,894 for a Method For
`Improved Line-Of-Sight Signal Detection Using RF Model
`Parameters, discloses a method for reducing time-shift due to
`multipathing for a RF signal in an RF environment.
`Close, US. Pat. No. 3,869,673 for a Method And Appara
`tus For Measuring Multipath Distortion, discloses a method
`for indicating multipath distortion in a received signal.
`Lennen, US. Pat. No. 5,402,450 for a Signal Timing Syn
`chroniZer, discloses a method and apparatus for reducing the
`effects of multipath induced distortions on the accuracy of
`detecting the time of arrival of a received signal.
`Fortune et al., US. Pat. No. 5,450,615 for a Prediction Of
`Indoor Electromagnetic Wave Propagation For Wireless
`Indoor Systems, discloses techniques for predicting RF
`propagation Within a structure.
`Other prior art references have disclosed the use of varying
`energy levels. For instance, Nakanishi, US. Pat. No. 5,451,
`847 for a Variable Energy Radio Frequency Quadrupole
`Linac discloses changing radio frequency energy levels to
`emitted focused and accelerated beams.
`KaeWell, Jr. et al., US. Pat. No. 7,082,286 for a Path
`Searcher Using Recon?gurable Correlator Sets discloses pro
`ducing a path pro?le for a user based on sorted output energy
`levels.
`FemabdeZ-Cobaton et al., US. Pat. No. 6,697,417 for a
`System And Method Of Estimating Earliest Arrival Of
`CDMA ForWard And Reverse Link Signals discloses a
`mobile station receiver that detects the arrival times and
`energy levels of received signals, and constructs a searcher
`histogram and a ?nger histogram associated With each pilot
`signal.
`The prior art has yet to resolve mistaken location calcula
`tions based on multipath effects for objects tracked Within an
`indoor facility.
`
`BRIEF SUMMARY OF THE INVENTION
`
`The present invention provides a solution to mistaken loca
`tion calculations based on multipath effects. The present
`invention determines a real-time location of an object in a
`facility using a combination of location algorithms, With a
`signal characteristic for a Wireless signal from the object
`received at a sensor of a mesh netWork.
`One aspect of the present invention is a method for deter
`mining a real-time location of an object Within a facility using
`a combination of location algorithms. The method includes
`transmitting a Wireless signal from a communication device
`associated With an object. The method also includes receiving
`the Wireless signal at least one sensor positioned Within a
`facility. The method also includes determining a real-time
`location of the object in the facility using a combination of
`
`0013
`
`

`
`US 8,457,656 B2
`
`3
`location algorithms With a power value for the Wireless signal
`received at the at least one sensor.
`Preferably the location algorithms preferably include at
`least tWo of a proximity algorithm, a radial basis function
`algorithm, a maximum likelihood algorithm, a genetic algo
`rithm, a minimum mean squared error algorithm, a radiofre
`quency ?ngerprinting algorithm, a multilateration algorithm,
`a time difference of arrival algorithm, a signal strength algo
`rithm, a time of arrival algorithm, an angle of arrival algo
`rithm, a spatial diversity algorithm, and a nearest neighbor
`algorithm. The location algorithms alternatively include at
`least one of a voting algorithm, an averaging algorithm and a
`con?dence algorithm. The at least one sensor forWards the
`Wireless signal to a plurality of location engines. Each of the
`plurality of location engines determines a real-time location
`of the object using a location algorithm. Determining a real
`time location of the object in the facility using a combination
`of location algorithms preferably comprises using a ?rst algo
`rithm if the object is detected in an in-room area and has a
`threshold received signal strength indication (“RSSI”), and
`using a second algorithm if the object is not in an in-room area
`or a threshold RSSI is not detected. The Wireless ?rst poWer
`level signal is preferably one of light, radiofrequency, sound
`and magnetic energy. Each of the plurality of location engines
`is preferably located at a single server. The method alterna
`tively further includes associating the transmitting object
`With a second object. The method alternatively further
`includes triggering an event. The event is preferably at least
`one of commencing a Work?oW event, changing the status of
`a Work?oW process, transmitting an alert, transmitting a
`report, changing the status of a computer, activating a camera,
`and changing the state of light.
`The method further includes associating the object With a
`second object. The method further includes triggering an
`event such as commencing a Work?oW event, transmitting an
`alert, transmitting a report, logging onto a computer, logging
`off of a computer, activating a camera, and activating a light.
`Another aspect of the present invention is a system for
`determining a real-time location of an object Within a facility.
`The system preferably includes objects, sensors and location
`engines. Each of the objects comprises a communication
`device Which transmits a Wireless signal. Each of the sensors
`is positioned Within the facility, and at least one of the sensors
`receives the Wireless signal. Each of the location engines is in
`communication With each of the sensors. Each of the location
`engines determines a real-time location of the object from the
`Wireless signal utiliZing a location algorithm.
`Location algorithms for each of the location engines pref
`erably includes at least tWo of a proximity algorithm, a radial
`basis function algorithm, a maximum likelihood algorithm, a
`genetic algorithm, a minimum mean squared error algorithm,
`a radiofrequency ?ngerprinting algorithm, a multilateration
`algorithm, a time difference of arrival algorithm, a signal
`strength algorithm, a time of arrival algorithm, an angle of
`arrival algorithm, a spatial diversity algorithm, and a nearest
`neighbor algorithm. The object is preferably a medical device
`or a person. A location algorithm for each of the location
`engines alternatively includes at least one of a voting algo
`rithm, an averaging algorithm and a con?dence algorithm.
`Yet another aspect of the present invention is a method for
`determining a real-time location of an object Within a facility.
`The method includes receiving a Wireless signal from a com
`munication device of an object at least one of a plurality of
`sensors positioned Within a facility. The method also includes
`forWarding the Wireless signal from the at least one of a
`plurality of sensors to a ?rst location engine. The method also
`includes forWarding the Wireless signal from the at least one
`
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`of a plurality of sensors to a second location engine. The
`method also includes calculating a real-time location of the
`object from the Wireless signal utiliZing a ?rst location algo
`rithm at the ?rst location engine. The method also includes
`calculating a real-time location of the object from the Wireless
`signal utiliZing a second location algorithm at the second
`location engine. The method also includes determining a
`real-time location of the object using the calculation from the
`?rst location engine and the calculation from the second
`location engine.
`The ?rst location algorithm is preferably one of a proxim
`ity algorithm, a radial basis function algorithm, a maximum
`likelihood algorithm, a genetic algorithm, a minimum mean
`squared error algorithm, a radiofrequency ?ngerprinting
`algorithm, a multilateration algorithm, a time difference of
`arrival algorithm, a signal strength algorithm, a time of arrival
`algorithm, an angle of arrival algorithm, a spatial diversity
`algorithm, and a nearest neighbor algorithm. The second
`location algorithm is preferably one of a proximity algorithm,
`a radial basis function algorithm, a maximum likelihood algo
`rithm, a genetic algorithm, a minimum mean squared error
`algorithm, a radiofrequency ?ngerprinting algorithm, a mul
`tilateration algorithm, a time difference of arrival algorithm,
`a signal strength algorithm, a time of arrival algorithm, an
`angle of arrival algorithm, a spatial diversity algorithm, and a
`nearest neighbor algorithm. The Wireless signal is preferably
`one of light, radiofrequency, sound and magnetic energy. The
`?rst location algorithm or the second location algorithm is
`alternatively at least one of a voting algorithm, an averaging
`algorithm and a con?dence algorithm.
`Having brie?y described the present invention, the above
`and further objects, features and advantages thereof Will be
`recogniZed by those skilled in the pertinent art from the fol
`loWing detailed description of the invention When taken in
`conjunction With the accompanying draWings.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWINGS
`
`FIG. 1 is schematic vieW of a system for determining a
`real-time location of an object Within a facility.
`FIG. 2 is a multi-?oor vieW of a facility employing a system
`for determining a real-time location of an object Within a
`facility.
`FIG. 2A is an isolated enlarged vieW ofcircle 2A ofFIG. 2.
`FIG. 2B is an isolated enlarged vieW ofcircle 2B ofFIG. 2.
`FIG. 3 is a ?oor plan vieW of a single ?oor in a facility
`employing the system for determining a real-time location of
`an object Within a facility.
`FIG. 4 is a tWo-?oor vieW of a facility including a tagged
`object and sensors of a system for determining a real-time
`location of an object Within a facility.
`FIG. 5 is a How chart of a method determining a real-time
`location of an object Within a facility.
`FIG. 6 is a How chart of a method determining a real-time
`location of an object Within a facility.
`FIG. 7 is a block diagram of a communication device
`employing variable radiofrequency poWer level transmis
`sions.
`FIG. 8 is a block diagram of a communication device
`employing variable light intensity level transmissions.
`FIG. 9 is a block diagram of a communication device
`employing variable sound level transmissions.
`FIG. 10 is a block diagram of a communication device
`employing variable magnetic energy level transmissions.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`As shoWn in FIGS. 1-4, a system for tracking objects and
`persons Within a facility is generally designated 50. The sys
`
`0014
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`

`
`US 8,457,656 B2
`
`5
`tem 50 is capable of determining a real-time location of an
`object 100 Within a facility 70. The system 50 preferably
`includes a plurality of sensors 55, a plurality of bridges 56, a
`plurality of communication devices 60 and at least one locat
`ing engine 65 Which includes a processor for calculating the
`real-time location of objects Within the facility 70 utiliZing
`information provided by the sensors 55. One example of the
`components of the system 50 is disclosed in US. Pat. No.
`7,197,326, for a Wireless Position Location And Tracking
`System, Which is hereby incorporated by reference in its
`entirety. A more speci?c example of the sensors 55 is dis
`closed in US. Pat. No. 7,324,824, for a Plug-In Network
`Appliance, Which is hereby incorporated by reference in its
`entirety.
`The system 50 is preferably employed at a facility 70 such
`as a business o?ice, factory, home, hospital and/or govem
`ment agency building. The system 50 is utiliZed to track and
`locate various objects and/or persons positioned throughout
`the facility 70. A communication device 60 is attached to an
`object or person. The communication devices 60 preferably
`continuously transmit signals on a predetermined time cycle,
`and these signals are received by sensors 55 positioned
`throughout the facility 70. Alternatively, the communication
`devices 60 transmit signals in a random, ad-hoc or dynamic
`manner, and these signals are received by the sensors 55
`positioned throughout the facility 70. As discussed beloW, in
`order to mitigate multipath effects, the communication
`devices 60 transmit signals at various poWer levels. The sen
`sors 55 transmit the data from the communication devices 60
`to a bridge 56 for transmission to a locating engine 65. If a
`sensor 55 is unable to transmit to a bridge 56, the sensor 55
`may transmit to another sensor 55 in a mesh network-like
`system for eventual transmission to a bridge 56. In a preferred
`embodiment, a transmission is sent from a transmission dis
`tance of six sensors 55 from a bridge 56. Alternatively, a
`transmission is sent from a transmission distance ranging
`from ten to tWenty sensors 55 from a bridge 56. The locating
`engine 65 preferably continuously receives transmissions
`from the sensors 55 via the bridges 56 concerning the move
`ment of objects 100 bearing a communication devices 60
`Within the facility 70. The locating engine 65 processes the
`transmissions from the sensors 55 and calculates a real-time
`position for each of the objects 100 bearing a communication
`device 60 Within the facility 70 utiliZing multiple location
`algorithms. The real -time location information for each of the
`objects 100 bearing a communication device 60 is preferably
`displayed on an image of a ?oor plan of the facility 70, or if the
`facility 70 has multiple ?oors, then on the ?oor plan images of
`the ?oors of the facility 70. The ?oor plan image may be used
`With a graphical user interface of a computer, personal digital
`assistant, or the like so that an individual of the facility 70 is
`able to quickly locate objects 100 Within the facility 70.
`As shoWn in FIG. 1, the system 50 utiliZes sensors 55 to
`monitor and identify the real-time position of non-stationary
`objects or persons bearing or integrated With communication
`devices 60. The sensors 55a-f preferably form a mesh net
`Work and Wirelessly communicate With each other (shoWn as
`double arroW lines) and With at lest one locating engine 65,
`preferably through a Wired connection 66 via at least one
`bridge 56, such as disclosed in the above-mentioned US. Pat.
`No. 7,324,824 for a Plug-In NetWork Appliance. The com
`munication devices 60a-c transmit signals at various poWer
`levels (shoWn as dashed lines) Which are received by the
`sensors 55a-e, Which then transmit signals to bridges 56 for
`eventual transmission to a central processor 65. The locating
`engine(s) 65 is/ are preferably located on-site at the facility 70.
`HoWever, the system 50 may also include an off-site locating
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`engine(s) 65, not shoWn. Those skilled in the pertinent art Will
`recogniZe that a single server may include more than one
`locating engine 65.
`In a preferred embodiment, each communication device 60
`preferably transmits a radio frequency signal of approxi
`mately 2.48 GigaHertZ (“GHZ”). The communication format
`is preferably IEEE Standard 802.154. Alternatively, each
`communication device 60 transmits an infrared signal, an
`ultrasound signal or a magnetic signal. Each communication
`device 60 preferably transmits at a plurality of transmission
`poWer levels, preferably ranging from tWo to tWenty different
`transmission poWer levels (energy levels), more preferably
`from tWo to ten different transmission poWer levels, and most
`preferably tWo different transmission poWer levels. Altema
`tively, the transmission poWer levels are the same. The num
`ber of communication device transmission poWer levels var
`ies depending on data transmission constraints and time
`constraints for the system. In one preferred embodiment, the
`?rst poWer level is approximately 1 milli-Watt and the second
`poWer level is approximately 0.5 milli-Watt. In a preferred
`embodiment, the communication device 60 transmits each
`signal at a different poWer level before transmitting again at
`the original poWer level. Alternatively, the communication
`device 60 transmits at a sequence of poWer levels that can be
`predicted by the sensors 55, bridges 56 and/ or central proces
`sor 65. For example, the communication device 60 transmits
`a ?rst signal at a ?rst poWer level and the next signal at a
`second poWer level. Those skilled in the pertinent art Will
`recogniZe that the communication devices 60 may operate at
`various frequencies and mediums (infrared, ultrasound and
`others) Without departing from the scope and spirit of the
`present invention.
`As shoWn in FIGS. 2, 2A, 2B, 3 and 4, the facility 70 is
`depicted as a hospital. The facility 70 has a multitude of ?oors
`75a-c. An elevator 80 provides access betWeen the various
`?oors 75a, 75b and 750. Each ?oor 75a, 75b and 750 has a
`multitude of rooms 90a-i, With each room 90 accessible
`through a door 85. Positioned throughout the facility 70 are
`sensors 5511-0 for obtaining readings from communication
`devices 60a-d attached to or integrated into non-stationary
`objects 100a, 100b (see FIGS. 2 and 4). A bridge 56 is also
`shoWn for receiving transmissions from the sensors 55 for
`processing by the central processor 65. The sensor 55 may
`have an antenna architecture such as disclosed in US. patent
`application Ser. No. 12/554,814 for Antenna Diversity For
`Wireless Tracking System And Method, Which is hereby
`incorporated by reference in its entirety.
`As shoWn in FIG. 4, the communication device 6011 is
`attached to movable bed 100a positioned on an upper ?oor
`750. The communication device 6011 transmits a signal Which
`is received by sensors 55a, 55b and 550. If the signal to the
`sensor 550 is the strongest, then an analysis of the readings
`from the sensors 55a-c may place the communication device
`60a, and thus the movable bed 10011, at position 60' on the
`loWer ?oor 75b. This type of faulty reading Would likely
`occur With triangulation. To prevent such a faulty positioning
`reading, the present invention processes the readings prefer
`ably according to a method Which eliminates the reading from
`sensor 550 from the location calculation for movable bed
`100a.
`A method 1000 for determining a real-time location of an
`object Within a facility is illustrated in FIG. 5. At block 1001,
`a Wireless signal is transmitted form a ?rst communication
`device associated With an object. At block 1002, the Wireless
`signal is received at a ?rst sensor. At block 1003, the Wireless
`signal is transmitted to a ?rst location engine. At block 1004,
`the Wireless signal is transmitted to a second location engine.
`
`0015
`
`

`
`US 8,457,656 B2
`
`7
`At block 1005, a location is calculated from the Wireless
`signal utilizing a ?rst location algorithm. At block 1006, a
`location is calculated from the Wireless signal utiliZing a
`second location algorithm. At block 1007, a real-time loca
`tion of the object is determined using the location algorithms.
`The ?rst location algorithm is preferably one of a proximity
`algorithm, a radial basis function algorithm, a maximum like
`lihood algorithm, a genetic algorithm, a minimum mean
`squared error algorithm, a radiofrequency ?ngerprinting
`algorithm, a multilateration algorithm, a time difference of
`arrival algorithm, a signal strength algorithm, a time of arrival
`algorithm, an angle of arrival algorithm, a spatial diversity
`algorithm, and a nearest neighbor algorithm. The second
`location algorithm is preferably one of a proximity algorithm,
`a radial basis function algorithm, a maximum likelihood algo
`rithm, a genetic algorithm, a minimum mean squared error
`algorithm, a radiofrequency ?ngerprinting algorithm, a mul
`tilateration algorithm, a time difference of arrival algorithm,
`a signal strength algorithm, a time of arrival algorithm, an
`angle of arrival algorithm, a spatial diversity algorithm, and a
`nearest neighbor algorithm.
`Another method 2000 for determining a real-time location
`of an object Within a facility is illustrated in FIG. 6. At block
`2001, a Wireless signal is received at a ?rst sensor. At block
`2002, a signal characteristic of the Wireless signal is trans
`mitted to a location engine. At block 2003, the signal charac
`teristic is inputted into an algorithm at the location engine. At
`block 2004, a determination is made for Which sub-algorithm
`to use for the signal characteristic. At block 2005, a real-time
`location of the object is determined using the sub-algorithm.
`A sub-algorithm is an algorithmic module Which is complete
`in itself and is used or called by a primary algorithm or by
`some other sub-algorithm. The sub-algorithm may or may not
`receive values from the primary algorithm. The sub-algo
`rithm performs its task and then sends the result to the primary
`algorithm.
`A communication device 60 that utiliZes different poWer
`levels of radiofrequency signals is illustrated in FIG. 7. A
`microcontroller 101 has programmed softWare to modify
`poWer levels from transmission to transmission. The trans
`missions are transmitted through transceiver (Wireless net
`Work interface) 103. A poWer supply 105 provides poWer to
`the device 60. All of the components are preferably contained
`Within a housing 107. The communication device 60 utiliZes
`different poWer levels of radiofrequency and preferably oper
`ates at a communication format that preferably includes IEEE
`Standard 80215.4, ZIGBEE, BLUETOOTH, BLUETOOTH
`loW energy, WiFi, LoW-poWer WiFi, Ultrasound and Infrared
`communication formats. Those skilled in the pertinent art Will
`recogniZe that other communication formats may be used
`With departing from the scope and spirit of the present inven
`tion. The communication format also alloWs the communica
`tion device 60 to communicate With the sensors 55 to transmit
`information. The communication device 60 may also operate
`at a short range communication format of magnetic induction,
`9 kHZ, <125 kHZ, 125 kHZ RFID, 13.56 MHZ, 433 MHZ, 433
`MHZ RFID, and 900 MHZ RFID, and preferably at a bit rate
`of less 256 kilobits per second or approximately 426 kilobits
`per second
`A communication device 6011 that utiliZes different poWer
`levels of light is illustrated in FIG. 8. A microcontroller 201
`has programmed softWare to modify poWer levels from trans
`mission to transmission. The transmissions are transmitted
`through LED 203, preferably an infrared transceiver. A poWer
`supply 205 provides poWer to the device 60a. All of the
`components are preferably contained Within a housing 207. In
`utiliZing the communication device 6011 of FIG. 8, each sen
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`sor 55 of the mesh netWork preferably inc