(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2003/0129995 A1
`(43) Pub. Date:
`Jul. 10, 2003
`Niwa et al.
`
`US 2003O129995A1
`
`(54) MOBILE TERMINAL DEVICE AND
`POSITIONAL INFORMATION SYSTEM
`(75) Inventors: Satoshi Niwa, Tokyo (JP); Masaki
`Ichihara, Tokyo (JP)
`Correspondence Address:
`FOLEY AND LARDNER
`SUTE 500
`3000 KSTREET NW
`WASHINGTON, DC 20007 (US)
`(73) Assignee: NEC CORPORATION
`(21) Appl. No.:
`10/334,067
`(22) Filed:
`Dec. 31, 2002
`(30)
`Foreign Application Priority Data
`
`Jan. 7, 2002 (JP)...................................... 2002-000478
`
`Publication Classification
`
`(51) Int. Cl. .................................................... H04B 7700
`
`(52) U.S. Cl. .............................................. 455/456; 455/66
`
`(57)
`
`ABSTRACT
`
`A geomagnetic Sensor for detecting geomagnetism is pro
`vided in a mobile terminal device. The output value of the
`geomagnetic Sensor is compared with a first Set value that
`has been Set in advance, and the mobile terminal device is
`determined to be stationary when the output value of the
`geomagnetic Sensor continues to be Smaller than a first Set
`value for at least a first Set time period that has been Set in
`advance, and the mobile terminal device is determined to be
`moving when the output value of the geomagnetic Sensor
`fluctuates by at least the first set value. The determination
`results are transmitted to the base Station, and the base
`Station decreases the number of times for executing a
`process of registering the position of the mobile terminal
`device to the base station when the mobile terminal device
`is Stationary, and increases the number of times of executing
`the process for registering position when the mobile terminal
`device is moving.
`
`GPS
`RECEIVER
`POSIONAL
`INFORMATION
`ACQUISITION
`UNIT
`POSITIONAL
`INFORMATION
`
`UNIT
`
`STORAGE
`UNIT
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`MOBILE
`TERMINAL
`DEVICE
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`BASE
`STATION
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`s
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`20
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`WTRELESS
`UNIT
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`CALLER
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`CONTROL
`UNIT
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`POWER
`SUPPY
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`USER
`INTERFACE
`UNIT
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`Page 1 of 11
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`SAMSUNG EX-1204
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`Patent Application Publication
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`Jul. 10, 2003. Sheet 1 of 4
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`US 2003/0129.995 A1
`
`Fig. 1
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`MOBILE
`ERMINAL
`DEVICE
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`BASE
`STATION
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`GPS
`RECEIVER
`POSIONAL
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`4
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`CALLER
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`UNIT
`Effin
`WRELESS
`UNIT
`UNIT
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`18
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`POWER
`SUPPLY
`UNIT
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`16
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`CONTROL
`UNIT
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`USER
`INTERFACE
`UNIT
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`Page 2 of 11
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`

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`Patent Application Publication
`Fig. 2
`
`Jul. 10, 2003. Sheet 2 of 4
`
`US 2003/0129.995 A1
`
`EW DIRECTIONAL V
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`Page 3 of 11
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`

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`Patent Application Publication
`
`Jul. 10, 2003 Sheet 3 of 4
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`US 2003/0129995 A1
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`Page 4 of 11
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`

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`Patent Application Publication
`Fig. 5
`
`Jul. 10, 2003 Sheet 4 of 4
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`US 2003/0129995 A1
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`STATIONARY FLAG (INITIAL STATE)
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`TIME PERIOD
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`ALT FLAG
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`Page 5 of 11
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`

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`US 2003/0129995 A1
`
`Jul. 10, 2003
`
`MOBILE TERMINAL DEVICE AND POSITIONAL
`INFORMATION SYSTEM
`
`BACKGROUND OF THE INVENTION
`0001) 1. Field of the Invention
`0002 The present invention relates to a mobile terminal
`device that indicates the current position, and to a positional
`information System that includes this mobile terminal device
`and a base Station for Sending and receiving information.
`0003 2. Description of the Related Art
`0004.
`In recent years, the popularization of mobile ter
`minal devices as represented by portable telephones has
`been remarkable, and this popularization has seen the devel
`opment of mobile terminal devices having a variety of
`functions. The advent of mobile terminal devices that are
`capable of displaying the current position is just one
`example.
`0005. In a positional information system for acquiring
`positional information of the prior art, a GPS (Global
`Positioning System) receiver is provided in a mobile termi
`nal device Such as car navigation System, and radiowaves
`received from a plurality of GPS satellites are used to
`Specify the current position of the device. The position is
`displayed on a map by Superposing the current position of
`the device on map information that has been provided
`beforehand or on map information of the vicinity of the
`mobile terminal device that is transmitted from the base
`station that is set up in each of prescribed areas.
`0006 Known methods of specifying the current position
`of a mobile terminal device include a method in which the
`mobile terminal device is provided with a Speed Sensor and
`acceleration Sensor and the output of these Sensors is used to
`find the amount of movement from an initial position and
`thus specify the current position of the mobile terminal
`device, and a method in which the positional information
`that is calculated using the outputs of a speed Sensor and
`acceleration Sensor is used together with positional infor
`mation that is obtained by the above-described GPS.
`0007. The positional information system of the above
`described prior art can operate more effectively if a base
`station or the mobile terminal device itself can determine the
`state of the mobile terminal device, i.e., whether the mobile
`terminal device is currently Stationary or in motion.
`0008 However, the mobile terminal device and posi
`tional information System of the prior art were not provided
`with a means for determining the State of the mobile terminal
`device at the base Station or at the mobile terminal device
`itself.
`
`SUMMARY OF THE INVENTION
`0009. It is an object of the present invention to provide
`both a specific means for determining whether a mobile
`terminal device is moving or Stationary as well as a posi
`tional information System that is capable of using Such a
`means to operate effectively.
`0.010 To achieve the above-described object in the posi
`tional information System of the present invention, a geo
`magnetic Sensor is used to determine the State of a mobile
`terminal device and the determination results are Sent to a
`
`base Station. The period for executing a process of register
`ing the position of the mobile terminal device to the base
`Station is then made longer than a prescribed reference
`period when the mobile terminal device is Stationary, and the
`period of executing the process of registering the position is
`made shorter than the reference period when the mobile
`terminal device is moving.
`0011 Carrying out this process reduces the transmission
`and reception of unnecessary information between the
`mobile terminal device and the base Station. In addition, the
`ability to reduce the frequency of updating the position
`registration when the mobile terminal device is Stationary
`both reduces power consumption and reduces the amount of
`consumption of the power Supply that is provided in the
`mobile terminal device, and the mobile terminal device can
`therefore display positional information with greater effi
`ciency.
`0012. In addition, in the positional information device of
`the present invention, Set values that have been determined
`in advance according to the geomagnetic Strength in the
`vicinity of the base Station and that are a reference for
`determining the State of the mobile terminal device are
`transmitted from a base station to the mobile terminal
`device. Thus, despite changes in geomagnetism depending
`on location, the set values held by the mobile terminal
`device are updated to ideal values and the mobile terminal
`device can determine its own State with greater accuracy.
`0013 In the positional information system of the present
`invention, in response to an inquiry from a partner terminal
`device that wishes to Send or receive speech or information
`with a mobile terminal device, the base Station transmits the
`results of determining the State of the mobile terminal device
`to the partner terminal device. As a result, when the mobile
`terminal device and the partner terminal device communi
`cate speech, the partner terminal device can, according to the
`State of the mobile terminal device, abandon the Speech
`communication and convert to character communication or
`delay the conversation time. For example, a mobile terminal
`device that is moving at high Speed is generally in a car or
`on a train, and converting to character communication or
`delaying the conversation time can thus therefore prevent
`accidents caused by conversing while driving or prevent a
`breaches of etiquette by reducing conversation on a train.
`0014. The above and other objects, features, and advan
`tages of the present invention will become apparent from the
`following description with reference to the accompanying
`drawings, which illustrate examples of the present invention.
`BRIEF DESCRIPTION OF THE DRAWINGS
`0015 FIG. 1 is a block diagram showing an example of
`the construction of a positional information System and a
`mobile terminal device of the present invention;
`0016 FIG. 2 is a schematic view showing an example of
`a geomagnetic Sensor that is provided in the State detection
`unit shown in FIG. 1;
`0017 FIG. 3 is a schematic view showing another geo
`magnetic Sensor that is provided in the State detection unit
`shown in FIG. 1;
`0018 FIG. 4 is a state transition chart showing the
`method of determining the state of the mobile terminal
`device of the present invention; and
`
`Page 6 of 11
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`

`

`US 2003/0129995 A1
`
`Jul. 10, 2003
`
`0019 FIG. 5 is a flow chart showing the procedures for
`determining the state of the mobile terminal device of the
`present invention.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`0020. To acquire positional information of a mobile ter
`minal device, there are constructions that employ the above
`described GPS and constructions that perform a calculation
`using the output of a Speed Sensor or acceleration Sensor. The
`positional information System of the present invention is
`described below taking as an example a construction in
`which a mobile terminal device uses GPS to obtain posi
`tional information.
`0021. As shown in FIG. 1, the positional information
`System of the present invention is a construction that
`includes mobile terminal device 1 that displays positional
`information and base Station 2 that transmits information to
`and receives information from mobile terminal device 1 by
`means of wireleSS communication. Base Station 2 is further
`connected to caller 4, which is another terminal device that
`Sends and receives Speech or information with mobile ter
`minal device 1 by way of an exchange (not shown in the
`figure). Further, when mobile terminal device 1 uses GPS to
`obtain positional information, mobile terminal device 1 and
`GPS satellite 3 are connected by way of a wireless means so
`as to allow transmission and reception of information.
`0022 Mobile terminal device 1 is a construction that
`includes: State detection unit 11 for detecting the State of
`mobile terminal device 1; clock unit 12 for detecting a
`prescribed time that has been Set in advance; control unit 13
`that is provided with a CPU (not shown in the figure) and
`memory (not shown in the figure) for temporarily holding
`information necessary for CPU processing and that performs
`processing to display positional information and map infor
`mation; positional information acquisition unit 20 for
`obtaining positional information; user interface unit 17 that
`is provided with a display device for displaying, for example
`positional information and map information, and an input
`device for receiving commands as input; wireleSS unit 18,
`which is a transceiver for implementing wireleSS communi
`cation with base Station 2; Storage unit 19 for Storing
`positional information and map information; and power
`Supply unit 16 that is provided with a battery for Supplying
`prescribed electrical power to each of State detection unit 11,
`clock unit 12, control unit 13, positional information acqui
`sition unit 20, user interface unit 17, wireless unit 18, and
`storage unit 19. Positional information acquisition unit 20 is
`a construction that includes, for example, GPS receiver 14
`for receiving radiowaves from GPS satellite 3 and positional
`information unit 15 for Specifying the current position of
`mobile terminal device 1 based on the Signal that has been
`received by GPS receiver 14.
`0023 Mobile terminal device 1 of the present invention
`is provided with a geomagnetic Sensor in State detection unit
`11 and uses azimuth information that is obtained from this
`geomagnetic Sensor to detect whether mobile terminal
`device 1 is moving or Stationary.
`0024. The geomagnetic Sensor is a Sensor capable of
`detecting only geomagnetism without being influenced by
`radiowaves that are emitted from mobile terminal device 1.
`The geomagnetic Sensor may employ, for example, a Sensor
`
`known as a flux gate-compass Such as shown in FIG. 2 that
`is provided with a toroidal core, an excitation coil, NS
`(North-South) directional detection coils, and EW (East
`West) directional detection coils, or may employ a Sensor
`such as shown in FIG. 3 that is composed of two Hall
`devices that are arranged in mutually orthogonal directions.
`The principles of detecting geomagnetism by means of these
`Sensors is described in detail in, for example Japanese Patent
`Laid-Open No. 305103/1997, and explanation is here omit
`ted.
`0025. In mobile terminal device 1 of the present inven
`tion having this type of construction, control unit 13 deter
`mines that mobile terminal device 1 is stationary when the
`output of the geomagnetic Sensor of State detection unit 11
`is observed to be equal to or less than a prescribed value for
`at least a particular fixed time period, as shown in FIG. 4.
`Alternatively, mobile terminal device 1 is determined to be
`moving when the output of the geomagnetic Sensor is
`observed to fluctuate by at least a prescribed value. Finally,
`mobile terminal device 1 is determined to be moving at high
`Speed when this fluctuation is observed to be great, and
`mobile terminal device 1 is determined to be moving at low
`Speed when the fluctuation is slight.
`0026. The geomagnetic Sensor is constantly in operation,
`and State detection unit 11 constantly sends the output value
`of the geomagnetic sensor to control unit 13. Control unit 13
`determines and monitors the State of mobile terminal device
`1 based on the above-described determination reference, and
`when mobile terminal device 1 is Stationary, decreases the
`number of processes for acquiring positional information by
`means of GPS receiver 14 and positional information unit
`15. When mobile terminal device 1 is moving, on the other
`hand, control unit 13 raises the frequency of processing for
`acquiring positional information by means of GPS receiver
`14 and positional information unit 15. In other words, the
`period for executing processing to acquire positional infor
`mation is made longer than a preset reference period when
`mobile terminal device 1 is Stationary, and the period for
`executing processing to acquire positional information is
`made shorter than the reference period when mobile termi
`nal device 1 is moving.
`0027 Reducing the number of processes for acquiring
`positional information when mobile terminal device 1 is
`Stationary decreases the number of instances of operation of
`GPS receiver 14 which has high power consumption, and
`therefore enables a reduction in power consumption. On the
`other hand, increasing the frequency of processing for
`acquiring positional information when mobile terminal
`device 1 is moving allows mobile terminal device 1 to obtain
`more accurate positional information.
`0028. The display of positional information by means of
`the display device of user interface unit 17 may be halted
`when mobile terminal device 1 is Stationary. In this case,
`display on the display device is resumed when mobile
`terminal device 1 is moving or when there is an incoming
`call from caller 4. Halting display by the display device of
`user interface unit 17 when mobile terminal device 1 is
`Stationary enables a greater reduction in power consump
`tion.
`0029. In the positional information system of the present
`invention, the state of mobile terminal device 1 that is
`determined at control unit 13 is transmitted by way of
`
`Page 7 of 11
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`US 2003/0129995 A1
`
`Jul. 10, 2003
`
`wireless unit 18 to base station 2 for each prescribed period.
`Base Station 2 alters the frequency of transmission and
`reception for the positional registration process that is nec
`essary for Sending map information to mobile terminal
`device 1 based on the state information that has been
`received from mobile terminal device 1. In other words, the
`period for executing the position registration proceSS is
`made longer than the preset reference period when mobile
`terminal device 1 is Stationary, and the period for executing
`the position registration proceSS is made shorter than the
`reference period when mobile terminal device 1 is moving.
`Changing the frequency of updating the position registration
`according to the State of mobile terminal device 1 in this way
`decreases the processes for transmitting and receiving
`unnecessary information.
`0.030. Accordingly, mobile terminal device 1 can display
`accurate positional information with greater efficiency. In
`addition, reducing the frequency of updating position reg
`istration when mobile terminal device 1 is Stationary enables
`a reduction in power consumption and therefore enables a
`reduction of the amount of consumption of the battery that
`is provided in power Supply unit 16. Further, Storing map
`information in storage unit 19 of mobile terminal device 1 in
`advance eliminates the need for base Station 2 to execute
`position registration processing. In this case, base Station 2
`need not be provided with map information.
`0.031 AS described in the foregoing explanation, base
`Station 2 in the positional information System of the present
`invention is kept informed of the state of mobile terminal
`device 1. As a result, when caller 4 wishes to learn the State
`of mobile terminal device 1, which is its communication
`partner, and therefore makes an inquiry as to whether mobile
`terminal device 1 is stationary or moving (moving at high
`Speed), base station 2 may report the State of mobile terminal
`device 1 to caller 4.
`0032. In this case, caller 4 can abandon the speech
`communication and, depending on the State of mobile ter
`minal device 1, convert the Speech communication to char
`acter communication or delay the conversation time. For
`example, because mobile terminal device 1 is usually in a
`car or on a train when mobile terminal device 1 is moving
`at high Speed, conversion to character communication or
`delaying the time of conversation can prevent accidents that
`result from conversing while driving or can prevent breaches
`of etiquette that would result from talking in a train.
`0033. In addition, when mobile terminal device 1 that has
`been called from Caller 4 is not able to communicate
`because it is moving at high Speed, base Station 2 may report
`to caller 4 that mobile terminal device 1 is moving at high
`Speed and is therefore unable to communicate.
`0034) Further, when mobile terminal device 1 is lost,
`another telephone can be used to learn the current position
`or state of mobile terminal device 1 and thus facilitate a
`Search.
`0035. The procedures for determining the state of mobile
`terminal device 1 are next explained using the flow chart
`shown in FIG. 5.
`0.036 AS described in the foregoing explanation, the state
`of mobile terminal device 1 includes the three states: sta
`tionary, moving, and moving at high Speed; and when any
`
`flag indicating these States is raised, control unit 13 deter
`mines that mobile terminal device 1 is in the State corre
`sponding to that flag.
`0037. When mobile terminal device 1 is stationary, and
`moreover, when this State has continued for at least a fixed
`time period, control unit 13 raises a halt flag for halting the
`operation of GPS receiver 14, positional information unit 15,
`and user interface unit 17, and Stops power Supply unit 16
`from Supplying power to GPS receiver 14, positional infor
`mation unit 15, and user interface unit 17.
`0038. In mobile terminal device 1 of the present inven
`tion, mobile terminal device 1 is determined to be Stationary
`or moving (moving at high Speed) depending on whether
`change in the output value of the geomagnetic Sensor
`exceeds a predetermined first Set value. It is further deter
`mined whether mobile terminal device 1 is moving at low
`Speed or moving at high Speed depending on whether the
`change in the output value of the geomagnetic Sensor
`exceeds a predetermined Second Set value.
`0039 Mobile terminal device 1 of the present invention
`is provided with two timers (a first timer and a second timer)
`in clock unit 12, and control unit 13 determines that mobile
`terminal device 1 is Stationary when change in the output
`value of the geomagnetic Sensor is Smaller than the above
`described first Set value, and moreover, when this State
`exceeds a predetermined set time period (first set time
`period) of the first timer. Control unit 13 further halts the
`supply of power to GPS receiver 14 and positional infor
`mation unit 15 or user interface unit 17 when this state
`exceeds the predetermined Set time period of the Second
`timer (Second set time period).
`0040. As shown in FIG. 5, the initial state of mobile
`terminal device 1 is Stationary, this being a State in which the
`Stationary flag is raised. When the State detection process of
`mobile terminal device 1 begins from this State, control unit
`13 compares the output value of the geomagnetic Sensor and
`the first set value in Step 101 and, detects whether or not the
`output value of the geomagnetic Sensor is equal to or greater
`than the first set value to determine whether there has been
`a change in geomagnetism.
`0041) If there is no change in geomagnetism, control unit
`13 determines whether the first timer is operating or not in
`Step 102, and activates the first timer in Step 103 if the first
`timer is not operating. In Step 104, control unit 13 next
`determines whether the first timer has come to the end of its
`time period and the first Set time period has elapsed, and if
`the first Set time period has not elapsed, returns to the
`process of Step 101 and repeats the processes of Steps
`101-104. If the first set time period has elapsed, control unit
`13 raises a stationary flag in Step 105 and determines that
`mobile terminal device 1 is stationary.
`0042 Control unit 13 next activates the second timer in
`Step 106, and in Step 107, determines whether the second
`timer has reached the end of its time period and the Second
`Set time period has elapsed. If the Second Set time period has
`not elapsed, control unit 13 returns to the process of Step 101
`and repeats the processes of Steps 101-107. If the second set
`time period has elapsed, control unit 13 raises the halt flag
`in Step 108, and, as described above, causes power Supply
`unit 16 to halt the supply of power to GPS receiver 14,
`positional information unit 15, and user interface unit 17.
`
`Page 8 of 11
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`US 2003/0129995 A1
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`Jul. 10, 2003
`
`0043. If a change in geomagnetism is detected in the
`process of Step 101, control unit 13 determines in Step 109
`whether a halt flag is raised, and if a halt flag is raised, causes
`power Supply unit 16 to Start Supplying power to GPS
`receiver 14 and positional information unit 15 in Step 110.
`Further, if a halt flag is not raised, first timer and Second
`timer are each halted in Step 111.
`0044) Control unit 13 next compares the output value of
`the geomagnetic Sensor and the Second Set value in Step 112,
`and detects whether the output value of the geomagnetic
`Sensor is equal to or greater than the Second Set value.
`0.045. If the output value of the geomagnetic sensor is less
`than the Second Set value, control unit 13 raises a moving
`flag, determines in Step 113 that mobile terminal device 1 is
`moving at low Speed, and then returns to the process of Step
`101 and repeats the processes of Step 101 and Steps 109
`112. On the other hand, if the output value of the geomag
`netic Sensor is equal to or greater than the Second Set value,
`control unit 13 raises the moving at high Speed flag and
`determines that mobile terminal device 1 is moving at high
`speed in Step 114. Control unit 13 then returns to the process
`of Step 112 and repeats the process of comparing the output
`value of the geomagnetic Sensor and the Second Set value.
`0046. Due to the changes in geomagnetic strength result
`ing from the current position of mobile terminal device 1,
`the first Set value and Second Set value for detecting the State
`of mobile terminal device 1 are preferably rewritten. In the
`present invention, the area that is managed by the positional
`information system is divided into a plurality of blocks
`according to the geomagnetic Strength and optimum first Set
`values and Second Set values are then registered for the
`blocks in each base station 2. When mobile terminal device
`1 uses GPS to obtain positional information, the first set
`value and Second Set value that accord with the position are
`each received from base Station 2 and recorded in Storage
`unit 19. By the addition of this function, the first set value
`and Second Set value are updated to optimum values despite
`variations in geomagnetism according to location and the
`State of mobile terminal device 1 can be more accurately
`determined.
`0047 While a preferred embodiment of the present
`invention has been described using Specific terms, Such
`description is for illustrative purposes only, and it is to be
`understood that changes and variations may be made with
`out departing from the Spirit or Scope of the following
`claims.
`
`What is claimed is:
`1. A mobile terminal device, comprising:
`a positional information acquisition unit for acquiring
`positional information, which is information of the
`current location;
`a user interface unit for displaying Said positional infor
`mation;
`a power Supply unit for Supplying power to Said positional
`information acquisition unit and Said user interface
`unit, and
`a wireleSS unit for transmitting information to and receiv
`ing information from the outside;
`
`Said mobile terminal device further comprising:
`a geomagnetic Sensor for detecting geomagnetism; and
`a control unit for comparing the output value of Said
`geomagnetic Sensor with a first Set value that has
`been Set in advance; determining that said mobile
`terminal device is Stationary when the output value
`of Said geomagnetic Sensor continues to be less than
`Said first Set value for at least a first Set time period
`that has been Set in advance; and determining that
`Said mobile terminal device is moving when the
`output value of Said geomagnetic Sensor fluctuates
`by at least Said first Set value.
`2. The mobile terminal device according to claim 1,
`wherein Said control unit:
`determines that Said mobile terminal device is moving at
`high Speed when the output value of Said geomagnetic
`Sensor fluctuates by a value that is equal to or greater
`than a Second Set value that is greater than Said first Set
`value and that has been Set in advance; and
`determines that Said mobile terminal device is moving at
`a low Speed when the output value of Said geomagnetic
`Sensor fluctuates by a value that is equal to or greater
`than Said first Set value and moreover, that is Smaller
`than Said Second Set value.
`3. The mobile terminal device according to claim 1,
`wherein Said control unit:
`makes the period of executing a positional information
`acquisition process for acquiring positional information
`longer than a reference period that has been Set in
`advance when Said mobile terminal device is Stationary,
`and
`makes Said period of executing Said positional informa
`tion acquisition process shorter than Said reference
`period when said mobile terminal device is moving.
`4. The mobile terminal device according to claim 1,
`wherein Said control unit causes a halt of the Supply of
`power from Said power Supply unit to Said positional infor
`mation acquisition unit and Said user interface unit when the
`output value of Said geomagnetic Sensor continues to be a
`value that is Smaller than Said first Set value for a time period
`that is equal to or greater than a Second Set time period that
`has been Set in advance in addition to Said first Set time
`period.
`5. A positional information System comprising:
`a mobile terminal device according to claim 1; and
`a base Station that holds map information of its own
`vicinity and transmits the map information to Said
`mobile terminal device.
`6. A positional information System comprising:
`a mobile terminal device according to claim 1; and
`a base Station that holds a first Set value that is Set in
`advance in accordance with the geomagnetic strength
`in its own vicinity and that transmits Said first Set value
`to Said mobile terminal device.
`7. A positional information System, comprising:
`a mobile terminal device according to claim 2, and
`a base Station: that holds a first Set value that is Set in
`advance in accordance with the geomagnetic strength
`in its own vicinity and a Second Set value that is greater
`
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`US 2003/0129995 A1
`
`Jul. 10, 2003
`
`than Said first Set value; and that sends each of Said first
`Set value and Said Second Set value to Said mobile
`terminal device.
`8. The positional information System according to claim
`5, wherein:
`Said mobile terminal device communicates to Said base
`Station determination results regarding whether Said
`mobile terminal device is Stationary or moving, and
`Said base Station:
`when Said mobile terminal device is Stationary, makes
`the period of executing a position registration pro
`ceSS of Said mobile terminal device to Said base
`Station longer than a reference period that has been
`Set in advance; and
`when Said mobile terminal device is moving, makes the
`period of executing Said position registration proceSS
`Shorter than Said reference period.
`9. The positional information System according to claim
`6, wherein:
`Said mobile terminal device communicates to Said base
`Station determination results regarding whether Said
`mobile terminal device is Stationary or moving, and
`Said base Station:
`when Said mobile terminal device is Stationary, makes
`the period of executing a position registration pro
`cess of Said mobile terminal device to said base
`Station longer than a reference period that has been
`Set in advance; and
`when Said mobile terminal device is moving, makes the
`period of executing Said position registration proceSS
`Shorter than Said reference period.
`10. The positional information System according to claim
`7, wherein:
`Said mobile terminal device communicates to Said base
`Station determination results regarding whether Said
`mobile terminal device is Stationary or moving, and
`Said base Station:
`when Said mobile terminal device is Stationary, makes
`the period of executing a position registration pro
`ceSS of Said mobile terminal device to Said base
`Station longer than a reference period that has been
`Set in advance; and
`when Said mobile terminal device is moving, makes the
`period of executing Said position registration proceSS
`Shorter than Said reference period.
`11. The positional information System according to claim
`5, wherein:
`Said mobile terminal device reports to Said base Station
`determination results regarding whether Said mobile
`terminal device is Stationary or moving, and
`Said base Station, in response to an inquiry from a partner
`terminal device that wishes to transmit