US 6,738,628 B1
`(10) Patent N0.:
`(12)Un1ted States Patent
`McCall et al.
`(45) Date of Patent:
`May 18, 2004
`
`
`U5006738628B1
`
`(54) ELECTRONIC PHYSICAL ASSET
`TRACKING
`
`(75)
`
`Inventors: Colin David McCall, Glasgow (GB);
`.
`-
`-
`Andrew Llam Massey’ AyrShlre (GB)’
`Neil Lindsay Robertson, Ayrshire (GB)
`
`(73) Assignee:
`
`International Business Machines
`Corporation, Armonk, NY (US)
`
`*
`
`Notice:
`
`J
`y
`Sub'ect to an disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/505,116
`
`(22)
`
`Filed:
`
`Feb. 16, 2000
`
`.......... 340/539
`4,792,796 A * 12/1988 Bradshaw et a1.
`5,686,892 A * 11/1997 Smith ...................... 340/568.7
`5,850,609 A
`12/1998 Sugarbroad et a1.
`........ 455/456
`
`29(133’3341‘ 2 * 1411/3888 35mg) tul~~~~~~~~~~~~~~~~~~~~ 342531455?
`,
`,
`*
`er
`e a.
`.........
`.
`............ 455/456
`6,339,709 B1 *
`1/2002 Gladwin et a1.
`6,347,229 B1 *
`2/2002 Zelmanovich et a1.
`455/456.1
`
`FOREIGN PATENT DOCUMENTS
`
`EP
`EP
`GB
`WO
`
`0199266
`0874248
`2316580
`9845728
`
`4/1986
`4/1998
`2/1998
`10/1998
`
`............ H04Q/7/04
`GOIS/5/14
`
`H04Q/7/38
`............. GOIS/1/68
`
`* cited by examiner
`
`Primary Examiner—Sonny Trinh
`(74) Attorney, Agent, or Firm—Gerald R. Woods
`
`(30)
`
`Foreign Application Priority Data
`
`(57)
`
`ABSTRACT
`
`Sep. 3, 1999
`
`(GB) ............................................. 9920722
`
`Int. Cl.7 .................................................. H04Q 7/20
`(51)
`
`. 455/456.1; 455/422.1;
`(52) US. Cl.
`......
`455/458; 340/825.43
`(58) Field of Search .......................... 455/41, 456, 458,
`455/466, 422, 9, 134, 229, 456.1, 4221,
`340/991, 992, 988, 989, 825.49, 572.1,
`572.4, 5.8, 10.1, 505
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`Objects can be tracked within a building using a radio device
`associated with each object to be tracked and an array of
`transmitting beacons. Each of the beacons transmits identi-
`fication data. The received identification data from the object
`to be tracked is sent
`to a server which determines the
`
`location of the object. The identification data may be sent
`from the object to the server using a data communications
`network such as a local area network. The beacons may have
`a variable power output allowing the receipt or non-receipt
`of the signal from the beacon to be used to assist in locating
`the object. The beacons may be associated with an existing
`wireless communication mechanism, such as Bluetooth.
`
`3,618,059 A * 11/1971 Allen ......................... 340/539
`4,021,807 A *
`5/1977 Culpepper et a1.
`.......... 342/458
`
`2 Claims, 3 Drawing Sheets
`
`
`BEACON TRANSMITS SIGNAL
`
`302
`
`ASSET RECEIVES BEACON SIGNAL
`
`
`
`ASSET CAPTURES BEACON ID
`
`
`
`
`
`304
`
`
`
`306
`
`
`308
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`
`
`
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`
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`ASSET SENDS BEACON ID TO SERVER
`
`
`
`
`
`
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`SERVER COMPUTES LOCATION
`
`SERVER STORES LOCATION
`
`311+
`
`316
`
`310
`
`
`
`312
`
`402
`
`400
`
` MOVE DETECTION
`
`SYSTEM
`
`1
`
`APPLE 1005
`
`APPLE 1005
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`1
`
`

`

`US. Patent
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`May 18, 2004
`
`Sheet 1 0f3
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`US 6,738,628 B1
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`2
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`

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`US. Patent
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`May 18, 2004
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`Sheet 2 0f3
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`US 6,738,628 B1
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`136
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`138
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`3
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`

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`US. Patent
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`May 18, 2004
`
`Sheet 3 0f3
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`US 6,738,628 B1
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`START
`
`302
`
`BEACON TRANSMITS SIGNAL
`
`301+
`
`ASSET RECEIVES BEACON SIONAL
`
`306
`
`ASSET CAPTURES BEACON ID
`
`308
`
`ASSET SENOS BEACON IO TO SERVER
`
`310
`
`SERVER COMPUTES LOCATION
`
`312
`
`SERVER STORES LOCATION
`
`314
`
`«am 316
`
`(+02
`
`110 400
`
`MOVE DETECTION
`
`SYSTEM
`
`FIG I.
`
`4
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`

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`US 6,738,628 B1
`
`1
`ELECTRONIC PHYSICAL ASSET
`TRACKING
`
`FIELD OF THE INVENTION
`
`The present invention relates to systems for tracking the
`location of objects by means of a transceiver or a receiver
`associated with each of the objects together with a chain of
`transceiving or transmitting radio beacons and a conven-
`tional computer network.
`
`BACKGROUND OF THE INVENTION
`
`In any organisation where physical information technol-
`ogy (IT) hardware assets such as personal computers,
`mobiles computers, server computers and printers are used,
`it is important to effectively manage each asset. One area of
`IT asset management which is regarded as time consuming,
`difficult and very expensive, is recording the physical posi-
`tion of each IT asset. The problem is further exacerbated
`with the present large scale adoption of mobile computing
`devices, which are easily transported, but are difficult to
`track. Losing control of the physical location of assets leads
`to accounting irregularities and investment planning disrup-
`tion.
`
`The most widely adopted method is physical inventory
`taking. This involves identifying and recording each asset by
`either physically going to it, or getting users to send data to
`a central point. This is not a good solution because:
`(i) Users don’t always respond;
`(ii) Data is only current for that moment in time, i.e. a user
`can enter data and then move the asset;
`(iii) Is not very secure; and
`(iv) Is time consuming.
`Integrated management applications generally rely on
`information entered by hand either at the managed system or
`at the management console to identify the system’s location.
`Often this information becomes out of date because the
`
`person moving the system is not aware that the information
`had to be updated, or how to update it.
`As systems management and troubleshooting becomes
`more automated, and pre-emptive maintenance is becoming
`more prevalent, alerts to the system manager that interven-
`tion is required at a remote system will come from the
`system itself, not the user, so it is imperative that location
`information is kept up to date. As an example, a bank branch
`system may report that intervention is required and as a
`result of the report, a technician is dispatched to the wrong
`town because the asset database is out of date.
`
`Asset tracking is a well understood problem and has had
`several solutions applied to try and solve. One method
`currently being used is the inclusion of a Radio Frequency
`Identification (RFID) chip inside the asset. The data on this
`chip (typically Vital Product Data (VPD)), can be scanned
`using a hand held scanner, without the need to remove the
`asset from the packaging. This approach records the VPD of
`the asset, but NOT the physical position, and is also confined
`to around a 1 meter distance between scanner and asset.
`
`Systems are known in which the location of individuals or
`objects are tracked by the use of tags attached to the
`individual or object. The tags receive a signal from a cell
`controller and reply by radio to the cell controller with the
`tags unique identification number. This unique identification
`number can be used to identify the individual or object to
`which the tag is attached. The location of the tag is estab-
`lished by calculating the distance of the tag from several
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`thus enabling the tag location to be
`different antennas,
`precisely determined. Typical of these products is the 3D-iD
`Local Positioning System from PinPoint Corporation. A
`description of the product can be found at www.pinpoint-
`co.com. The cell controllers typically have a range of 250
`feet (76 meters) and are dedicated for the purpose of asset
`tracking. The cell controllers calculate the tag location using
`precise time references to determine the distance of the tag
`from the controller.
`US. Pat. No. 5,708,423 discloses a zone based asset
`tracking and control system in which each object has an
`associated object marker which transmits a unique id signal.
`As the object moves through doorways its signal is received
`by a sensor which transmits this information to a central data
`processing system.
`Radio location solutions such as the Global Positioning
`System (GPS) can locate an asset to a very high degree of
`accuracy, and lightweight GPS implementations are
`inexpensive, but GPS does not work inside buildings. Other
`radio based location systems like Decca or Loran require
`expensive, specialised, radio frequency circuitry at both the
`beacon and the asset. Many radio based location systems
`depend on the use of directional antennae, either mechani-
`cally rotated or phased arrays.
`It would be desirable to provide an asset tracking system
`that did not require the use of dedicated hardware such as
`cell controllers and also did not require hardware that was
`required to use a precise time reference in order to determine
`the location of the tag.
`DISCLOSURE OF THE INVENTION
`
`Accordingly, the present invention provides apparatus for
`tracking the location of one or more objects, the apparatus
`comprising: one or more beacons, each beacon transmitting
`identification data; one or more radio devices, each radio
`device being associated with one of the objects, each radio
`device being capable of receiving a signal from any one or
`more of said beacons; data processing apparatus, in com-
`munication with the one or more objects, for receiving
`identification data from the one or more objects, the iden-
`tification data being derived from the transmitted identifi-
`cation data.
`
`The apparatus can be used to automatically updates
`location information in a manner that needs no user inter-
`
`vention and is transparent to the overall management sys-
`tem.
`
`The beacons can be part of an existing wireless commu-
`nication system using, for example, the Bluetooth technol-
`ogy. Such technology is likely to become standard equip-
`ment for mobile and desktop computing within a few years
`and is inexpensive to implement.
`The location mechanism uses a dense array of beacons,
`rather than a sparse array and so location does not depend on
`the direction of the beacons from the objects, only the
`presence of the beacon within range. because of this a
`simple, inexpensive omnidirectional antenna can be used.
`In a preferred embodiment, communication between the
`data processing apparatus and the one or more objects is
`through a data communications network, and more
`preferably, a local area network.
`In a preferred embodiment, only the receipt or non-receipt
`of a signal from the one or more beacons is used to
`determine the location of an object.
`In an alternative embodiment, one or more of the one or
`more beacons transmit at two or more different powers, the
`transmission containing information indicating the transmit
`5
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`

`US 6,738,628 B1
`
`3
`power, thereby allowing two or more different ranges from
`the one or more beacons to be determined.
`
`The invention also provides a method of tracking the
`location of one or more objects, the method comprising the
`steps of: transmitting identification data from one or more
`beacons; receiving said identification data using one or more
`radio devices, each radio device being associated with one
`of the objects, each radio device being capable of receiving
`a signal from any one or more of said beacons; transmitting
`the received identification data from the one or more objects
`to data processing apparatus.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Embodiments of the invention will now be described, by
`way of example, with reference to the accompanying
`drawings, in which:
`FIG. 1 shows assets and beacons located within a build-
`
`ing;
`FIG. 2 shows the assets and beacons of FIG. 1 according
`to a variation of the invention;
`FIG. 3 is a flowchart of the process of the present
`invention for determining the location of an asset; and
`FIG. 4 is a block diagram of component parts of a system
`according to the present invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`to be
`invention requires that each asset
`The present
`tracked is equipped with a radio device—either a transmitter
`and receiver, or just a receiver. FIG. 1 shows a plurality of
`radio ‘beacons’ 102—112 distributed throughout a floor of a
`building 100 in which assets 120, 122 are to be tracked.
`Although a plurality of radio beacons 102—112 is shown in
`FIG. 1, the present invention may be implemented using a
`single beacon within a building 100. The beacons 102—112
`are very simple devices which only need the capability of
`continuously transmitting an identifying signal where an
`asset contains just a receiver and of responding to a received
`signal in the case where an asset contains a transmitter and
`a receiver. The beacons may be dedicated devices, or may be
`attached to devices that are not expected to move,
`like
`department printers or LAN access points.
`The beacons 102—112 are laid out in an approximate grid
`pattern. The exact layout is not critical to operation of the
`present invention. In particular, a grid pattern is not required.
`It is merely desirable that the layout of beacons is such that
`coverage is provided over substantially all of the area of the
`building in which assets are to be tracked. As an example,
`where the nominal range of the beacon is 10 meters, a
`spacing of about 14 meters provides enough resolution and
`coverage for most purposes. In some applications a single
`beacon per building or floor transmitting at a higher power
`level would be sufficient.
`
`When an asset 120, 122 needs to identify its position, it
`transmits a signal
`inviting any beacons 102—112 within
`range to respond. The beacon responds with a signal con-
`taining a unique ID which is either burned into the radio
`hardware to make it globally unique or may be set by
`software, bit switches or similar means. In the example of
`FIG. 1, asset 122 transmits a signal inviting any beacons
`102—112 within range to respond. Beacon 110 responds with
`a unique identifier that is associated only with beacon 110.
`The location of asset 122 may now be determined as being
`within a defined range of beacon 110. Since the beacons in
`this example have a range of 10 meters, then the location of
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`asset 122 will now be known to within 10 meters. Also, in
`the example of FIG. 1, asset 120 transmits a signal inviting
`any beacons 102—112 within range to respond. Beacons 102
`and 104 respond with their unique identifiers that are asso-
`ciated only with those beacons 102, 104. The location of
`asset 120 may now be determined as being within a defined
`range of both beacons 102 and 104. No attempt is made to
`fix the direction or distance of any beacon. Only the pres-
`ence or absence of the beacon within the receiving range is
`required.
`In an alternative embodiment, the beacon 102—112 trans-
`mits its identifying signal continuously, or at intervals. The
`asset 120, 122 passively listens for beacons 102—112 that are
`transmitting either continuously or intermittently. In this
`alternative embodiment
`the beacon need not contain a
`receiver and the asset need not contain a transmitter.
`FIG. 2 shows an alternative embodiment in which the
`beacon 102—112 sends a sequence of signals at different
`power output levels, and the transmitted signal contains the
`power level at which it is transmitted, from which a nominal
`range can be determined. If an asset 122 receives a ‘10
`meter’ signal from a beacon 102—112 but not a ‘5 meter’
`signal, it can be assumed to be located between 5 and 10
`meters from the beacon 102—112. The 5 meter and 10 meter
`signals are treated as originating from different beacons in
`determining the location of the asset.
`Referring to FIG. 3, which is a flowchart showing the
`present invention. The location process starts at step 302. At
`step 304, a beacon 102—112 transmits a signal. As described
`above, this signal may have been transmitted in response to
`a request from an asset 120, 122 or the beacon may transmit
`the signal continuously or intermittently without a request
`being received from the asset. At step 306, the asset 120, 122
`receives the beacon signal. At step 308, the asset 120, 122
`decodes the signal to determine the beacon ID. If a signal is
`received from more than one beacon,
`then each of the
`signals is decoded to determine the beacon ID. At step 310,
`the asset 120, 122 sends the beacon ID to a central server.
`This transmission may be over any communications
`network, for example a LAN or a telephone network, or a
`wireless network comprising a relay system through the
`beacons themselves. At step 312, the server computes the
`physical location from the beacon ID, or the server detects
`a change of location of the asset determined from a list of
`beacons and a list of asset locations held by the server. At
`step 314, the server stores the location of the asset in an asset
`location database. At step 316, the location process ends.
`Referring to FIG. 4, which shows, in block diagram form,
`the component parts of a system according to the present
`invention. When the server 402 has determined the asset
`120, 122 location, it records the location in the asset location
`database 404. The data recorded may be just the beacon ID
`or IDs or it may be the physical position determined as
`described below. It may optionally report the position of the
`asset 120, 122 to a move detection system 400 or may return
`the location information to the asset 120, 122 where it can
`be made available to management systems. The Common
`Information Model of the Desktop Management Task Force
`defines standardised ways of making asset location data or
`alerts available to management systems. The Common
`Information Model (CIM) is a schema for describing man-
`agement information that is used to tie together existing
`differing management applications. Using this standard, the
`location information and move alerts could be integrated
`into any enterprise management system without special
`programming.
`The asset 120, 122 may also locally compute its position,
`or detect a change of position, without reference to an
`external system, and report the results to the server 402 in
`the same way.
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`US 6,738,628 B1
`
`5
`Radio signal propagation is expected to vary depending
`on atmospheric conditions. Since the present invention is
`intended to be used inside occupied buildings it is unlikely
`that there will be sufficient variation in conditions to disrupt
`the system.
`The preferred implementation uses Bluetooth digital radio
`technology. (see http://www.bluetooth.com/ for details of
`the technology).
`Bluetooth is an open specification for wireless commu-
`nication of data and voice. It is expected to be incorporated
`into mobile phones, mobile and desktop computers and
`domestic appliances so as to allow them to communicate
`with each other.
`It consists of a single chip transceiver
`operating in the unlicensed 2.4 GHz band with a nominal,
`but programmable, range of 10 centimeters to 100 meters.
`This waveband will pass readily through glass or plaster-
`board internal partitions, but not concrete or steel walls and
`floors, making it ideal for short range communications in a
`modern office or factory building. This standard specifies an
`‘inquire’ protocol whereby a device transmits a specified
`sequence of data packets, and any ‘listening’ device
`responds with its identifier, which is a globally unique
`number burned into the device firmware. As this technology
`is expected to become pervasive for communications
`between mobile computers and static devices, existing
`devices like printers or LAN or telephone access points
`could be used as beacons with no modification.
`
`The present invention takes advantage of the fact that
`devices such as printers or LAN or telephone access points
`installed in a building for other purposes can be used to
`provide the required beacons at no, or little, additional cost.
`Detecting Moves
`The asset 120, 122 determines its position every time it
`powers on, or every time it boots up if there is no way of
`detecting whether it has just powered on, or every time it
`connects to the network and optionally at regular intervals
`after that. If the asset 120, 122 is mobile, it should report
`every time it connects to a static network or at regular
`intervals if it uses a wireless network to report location.
`When the server 402 receives a position message from the
`asset 120, 122, it compares the list of beacons 102—112 in the
`position message with the list of beacons stored in the asset
`location database 404 for that asset. If they are substantially
`different, it alerts the asset administrator that the asset 120,
`122 has been moved, and if possible, where it has been
`moved to. The definition of ‘substantially different” will vary
`according to the environment
`in which the system is
`deployed.
`In some applications, the grid of beacons 102—112 can be
`completely partitioned, such as in an organization with
`buildings in many locations, a campus with several build-
`ings or a building with several floors where the concrete
`structure of the floor is for practical purposes completely
`impervious to the radio signals. In this case, if the asset 120,
`122 reports hearing any beacon 102—112 from a different
`partition, it can be considered a significant move.
`In some applications, where the layout and physical
`arrangement of the area is very stable, ANY change in the set
`of beacons 102—112 may be considered significant as there
`is a very high probability that this indicates a move.
`In a normal application, some variation in received sig-
`nals can be expected due to normal minor changes in area
`layout. For example, moving a metal filing cabinet may
`cause a receiver in an asset 120, 122 to lose a single beacon
`102—112, or lose the lowest power signal from a beacon but
`pick up the next highest, or pick up an extra beacon, in a
`setup where each asset is expected to be within range of
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`several beacons at any time. This would not be considered
`a significant change.
`In some applications, movement of an asset within a
`limited area may be acceptable. In these applications, the
`server computes from the clients ‘normal’ beacon set, a
`‘guardband set’ consisting of a ring of beacons immediately
`outside the normal set. If the system picks up one of these
`beacons, it can be considered an insignificant change, but if
`it picks up anything outside the guardband it is considered
`significant.
`If an asset does not report its position for an extended
`period, it may have been removed from the site/network or
`may simply be powered off. In this case the system could use
`Wake-on-LAN to power the machine up and have it report
`its position. If the machine wakes and reports that it can not
`detect any beacons, it has either been moved outside the
`range of the beacons, or has been moved into a local hole in
`the coverage. In either case some action is required. Failure
`to wake the system would indicate that
`the machine is
`disconnected from the network or power, and possibly
`removed from the site. This condition should cause an alert.
`
`Mapping the Area
`Mapping the area is not always necessary, but is required
`for absolute location of assets (see below) or for the ‘guard-
`band’ technique (above). To map the area initially, the user
`constructs a geographical map of the area in the server
`software, consisting of a set of grid points. Most modern
`buildings probably have a suitable map in computerized
`form already in the facilities management systems. It is not
`necessary for the beacon locations to be recorded on the
`map, but if they are then a good first approximation can be
`made for the set of beacons that should be received from any
`point on the map.
`The setup technician then moves systematically through
`the area with a mobile system with a receiver, listening to the
`beacon system. For a 15 meter beacon grid layout, mapping
`on a 5 meter grid would probably be acceptable. For an
`office with a regular pattern of ‘pens’ or ‘cubes’, the map-
`ping grid could usefully be based on the area layout. At each
`point on the grid, the system sends a message back to the
`server with its position, entered by the technician, and a list
`of the beacons it can receive. The server builds a map of the
`area with a list of beacons associated with each grid point.
`Every time a new asset is installed, its location and list of
`beacons may be added to the map to check and gradually
`improve resolution.
`Absolute Location of Assets
`
`When an absolute location of an asset is required, the
`asset sends a message with its list of beacons to the server.
`The server then searches its map for the closest matches, and
`reports the probable location to be at the matching grid
`point, or in the vicinity of one of a set of grid points if there
`are several close matches. The resolution depends on the
`layout of beacons and the accuracy of the map, but in the
`normal case should locate the asset to within a 10-meter
`radius, or better. The form of the location information
`produced may be customised to the organization. Some
`companies may use latitude and longitude or OS grid
`references. Some may use building and office numbers. In
`the case of an organization with many small branch offices,
`a postal address may be the most useful.
`We claim:
`
`1. Apparatus for tracking the location of one or more
`objects, the apparatus comprising:
`one or more beacons, each beacon transmitting identifi-
`cation data, each of said beacons transmitting to one of
`two or more different powers, the transmission con-
`
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`US 6,738,628 B1
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`7
`taining information indicating the transmit power,
`thereby allowing two or more different ranges from the
`one or more beacons to be determined;
`one or more radio devices, each radio device being
`associated with one of the objects, each radio device
`being capable of receiving a signal from any one or
`more of said beacons;
`data processing apparatus, in communication with the one
`or more objects by means of a data communications
`network separate from said beacons and said radio
`devices, for receiving identification data from the one
`or more objects, the identification data being derived
`from the transmitted identification data.
`
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`8
`transmitting identification data from one or more beacons,
`each of said beacons transmitting at one of two or more
`different powers, the transmission containing informa-
`tion indicating the transmit power, thereby allowing
`two or more different ranges from the one or more
`beacons to be determined;
`receiving said identification data using one or more radio
`devices, each radio device being associated with one of
`the objects, each radio device being capable of receiv-
`ing a signal from any one or more of said beacons;
`transmitting the received identification data from the one
`or more objects to data processing apparatus by means
`of a data communications network separate from said
`one or more beacons and said radio devices.
`
`2. A method of tracking the location of one or more
`objects, the method comprising the steps of:
`
`8
`
`