[DESCRIPTION]
[Invention Title]
COMMUNICATION METHOD FOR MONITORING LOCATION OF
CONSTRUCTION EQUIPMENT
[Technical Field]
[0001] The present invention relates to a communication method for monitoring the
position of a construction machine, and more particularly, to a communication method
for preventing a construction machine from being stolen by monitoring the position of
the construction machine with a communication means such as satellite communication
and mobile communication.
[Background Art]
[0002] A position monitoring apparatus or system that monitors and notifies a
position is generally used to verify and notify positions of persons and assets. A
general position monitoring apparatus combines a navigation system such as a global
positioning system (GPS) module and a mobile communication system such as a cell
type modem to determine the position of a person or an asset to be monitored, that is, a
geographical position and notify the position thereof to a control center or a monitoring
facility positioned in a remote area. The position monitoring apparatus or system is
used in various systems such as a logistics transportation tracking system and an asset
recovering system.
[0003] By the position monitoring apparatus, an owner or a manager of a movable
target determines the position of an asset that is in danger of being stolen or lost by
using positional information sent from the asset to be monitored to prevent a theft
danger or recover the lost asset.
[0004] In the case in which a monitoring target operates within a predetermined
movable area like the construction machine, an owner or manager previously can set a
boundary of the movable area and enable the construction machine to transmit various
pieces of information such as positional information and determines the position of the
construction machine based on the positional information thereof to track the position of
the corresponding construction machine when the construction machine deviates from
the boundary of the movable area. A so-called Geo-Fence System which monitors
motions or positions is used and this system provides a positional coordinate set
defining an area where the monitoring target can move and when the monitoring target
moves with deviating from a positional coordinate, this system helps recovering the
asset by notifying the fact to an owner of the target and/or a low enforcement agency
through a monitoring service.
[Disclosure]
[Technical Problem]
[0005] By a known position monitoring apparatus or method, a construction
machine which is a monitoring target can be configured to generate various pieces of
information such as positional information through a GPS and transmit the information
such as the positional information to a management unit (hereinafter, referred to as a
'remote management unit') which is positioned in a remote area. When the
construction machine continues to deviate from a movable area for a long time and
communication amount is thus increased, excessive power consumption may take place.
[0006] In particular, the information transmitted from the construction machine may
include state information such as engine temperature or a fuel level of the construction
machine, operation information associated with operation of the construction machine,
such as an operation hour or a working hour, and the like in addition to the positional
information in order for a remote owner or manager to manage the construction
machine efficiently. As the amount of the transmitted information increases,
consumed power also increases. For example, in the case in which power supplied to a
battery power driven type position monitoring apparatus is used up while the
construction machine transmits at least one piece of information to the owner or
manager (remote management unit), the corresponding construction machine may not
transmit information required by a monitoring facility any longer.
[0007] Meanwhile, the information transmitted from the construction machine to the
remote management unit is transmitted at a predetermined cycle. In this case, as the
transmission cycle is short, positional information close to a real time can be acquired,
but since a power amount for transmission is thus increased, setting an appropriate
transmission cycle is required. Further, when the construction machine is configured
to transmit the positional information, and the like at the predetermined cycle even
while the construction machine is in a starting off state, battery power of the
construction machine is used, and as a result, the amount or transmission cycle of
information to be transmitted needs to be efficiently determined.
[0008] The present invention is contrived to solve the problems in the related art.
An object of the present invention is provide a method and an apparatus capable of
effectively controlling the amount and transmission cycle of transmitted information
while maximally keeping low a transmission cost and power consumption of a
construction machine.
[Technical Solution]
[0009] In order to achieve the above-mentioned object, the present invention
controls a transmitted data amount other than positional information transmitted from a
construction machine to be reduced and a transmission cycle to be shortened when there
is a concern about theft of the construction machine or a theft possibility is high.

[0010] Objects and advantages other than the above-mentioned object and advantage
will be apparent through the following detailed description and accompanying drawings.
[Advantageous Effects]
[0011] According to the present invention, by controlling the amount and
transmission cycle of information to be transmitted according to a distance between a
boundary of a work allowance area and a construction machine, positional information
can be provided approximately in real time in a theft danger state or a theft state while
maximally keeping power consumption.
[Description of Drawings]
[0012] FIG 1 is a configuration diagram schematically showing a configuration in
which a construction machine and a monitoring facility communicate with each other
according to an exemplary embodiment of the present invention.
[0013] FIG 2 is a flowchart schematically showing each step of a method for
monitoring the position of a construction machine according to an exemplary
embodiment of the present invention.
[0014] FIG 3 is a flowchart schematically showing each step of a method for
monitoring the position of a construction machine according to another exemplary
embodiment of the present invention.
[0015] FIG 4 is a configuration diagram showing a movable area of a construction
machine which is partitioned according to an exemplary embodiment of the present
invention.
[0016] FIG. 5 is a diagram showing the relationship between a transmitted
information amount and a transmission cycle corresponding to a partitioned area
according to an exemplary embodiment of the present invention.
[0017] FIG. 6 is a diagram showing the relationship between a transmitted

information amount and a transmission cycle with the position of a construction
machine according to an exemplary embodiment of the present invention.
[0018] FIG 7 is a flowchart showing steps of controlling a transmitted information
amount and a transmission cycle according to an exemplary embodiment of the present
invention.
[0019] FIG. 8 is a block diagram showing an example of information monitoring
mounted on a construction machine according to an exemplary embodiment of the
present invention.
[Best Mode]
[0020] According to a first aspect of the present invention, a communication method
for monitoring the position of a construction machine includes: generating positional
information of the construction machine and at least one piece of state information and
at least one piece of operation information associated with the construction machine in
the construction machine; and transmitting the generated information to a remote
management unit which is positioned in a remote area from the construction machine by
using a communication means, in which the remote management unit partitions an area
where the construction machine is movable and previously determines the amount and
transmission cycle of information to be transmitted from the construction machine in
accordance with the partitioned area, and the amount of information to be transmitted
other than the positional information from the construction machine is reduced as the
construction machine is distant out of a boundary line of the movable area, on the basis
of the positional information received from the construction machine.
[0021] In the exemplary embodiment, the transmission cycle from the construction
machine may be shortened as the construction machine is distant out of the boundary
line of the movable area, on the basis of the positional information received from the
construction machine.
[0022] In another exemplary embodiment, the amount of the information other than
the positional information from the construction machine is reduced and the
transmission cycle thereof is shortened as the construction machine is close to the
boundary line within the movable area, and the amount of the information other than the
positional information from the construction machine is further reduced and the
transmission cycle thereof is further shortened as the construction machine is distant out
of the boundary line of the movable area, on the basis of the positional information
received from the construction machine.
[0023] In yet another exemplary embodiment, in the partitioning of the area where
the construction machine is movable, the area is at least partitioned into a first area, a
second area, a third area, and a fourth area in a direction distant from the center of the
movable area and the first area and the second area are set within the boundary line of
the movable area and in this case, the second area is set to contact the boundary line of
the movable area, and the third area and the fourth area are set out of the boundary line
of the movable area and in this case, the third area is set to contact the boundary line of
the movable area, and the transmission cycle is determined to be T1 > T2 > T3 > T4
(wherein, Tn represents a transmission cycle in an n-th area) and the amount of the
information to be transmitted is determined to be R1 < R2 < R3 < R4 = 1 (wherein, Rn
represents a ratio of positional information amount to total transmitted information
amount in the n-th area), in accordance with the partitioned area.
[0024] Hereinafter, exemplary embodiments of the present invention will be
described in more detail with reference to the accompanying drawings.
[0025] FIG. 1 is a configuration diagram schematically showing a configuration in
which a construction machine and a monitoring facility communicate with each other
according to an exemplary embodiment of the present invention.
[0026] In a communication method of the present invention, for example, positional
information of a construction machine 101 generated by using a position-related signal
received from a GPS satellite 102 and state and/or operation information of the
construction machine are transmitted from an information transmitting communication
apparatus mounted on the construction machine to a remote management unit by using
satellite communication or mobile communication facility 103, and the remote
management unit transmits a control signal to the construction machine 101 through the
satellite communication or mobile communication facility 103.
[0027] Hereinafter, a procedure in which the construction machine and a monitoring
facility communicate with each other in the present invention will be described in more
detail on the basis of the above-mentioned configuration.
[0028] FIG 2 is a flowchart schematically showing each step of a method for
monitoring the position of a construction machine according to an exemplary
embodiment of the present invention.
[0029] Referring to FIG. 2, first, a remote management unit positioned in a remote
area from the construction machine partitions an area where the construction machine
can move (step S210). The remote management unit previously determines the
amount and a transmission cycle of information to be transmitted depending on the
partitioned area (step S220). When the positional information is received from the
construction machine (step S230), communication power can be reduced by reducing
the amount of transmission information other than the positional information as the
construction machine becomes distant from a boundary line of the area where the
construction machine can be move based on the positional information thereof (step
S240). Meanwhile, the boundary line of the movable area may be a boundary line of
an area where the construction machine routinely operates in the movable area.
[0030] In the exemplary embodiment, the remote management unit may direct the
transmission cycle at which the construction machine transmits information to be
shortened as the construction machine becomes distant from the boundary line of the
area where the construction machine can move, on the basis of the positional
information received from the construction machine. As a result, when the
construction machine is positioned out of the boundary line of the movable area,
tracking of the position thereof becomes easier.
[0031] In the exemplary embodiment, the remote management unit reduces the
amount of the information other than the positional information received from the
construction machine and shortens the transmission cycle of the information as the
positions of the construction machine becomes close to the boundary line of the
movable area in the movable area, based on the positional information received from the
construction machine and further reduces the amount of the transmission information
other than the positional information received from the construction machine and
further shortens the transmission cycle as the construction machine becomes distant
from the boundary line of the movable area. As a result, when the construction
machine is positioned within the boundary line of the movable area, the transmission
power can be reduced by reducing the amount of the transmission information other
than the positional information even though the information transmission cycle from the
construction machine becomes faster as the construction machine becomes close to the
boundary line, that is, a possibility that the construction machine will be separated from
the boundary line of the movable area increases. Meanwhile, when the construction
machine becomes further distant out of the boundary line of the movable area, the
position of the construction machine can be smoothly tracked by further reducing the
amount of the information other than the positional information among the information
transmitted from the construction machine and further shortening the transmission cycle
thereof.
[0032] FIG. 3 is a flowchart schematically showing each step of a method for
monitoring the position of a construction machine according to another exemplary
embodiment of the present invention.
[0033] Referring to FIG 3, first, the remote management unit positioned in the
remote area from the construction machine partitions the area where the construction
machine can move (step S310) and previously determines the amount of the information
to be transmitted (alternatively, transmitted data amount) and the transmission cycle in
association with transmission of the information from the construction machine
depending on the partitioned area (step S320). Herein, the area where the construction
machine can move is an area arbitrarily set by a user or a manager and a boundary of the
movable area may be a general working area where the construction machine is allowed
to work. In the exemplary embodiment, the remote management unit may store, in a
table format, the amount and transmission cycle of information to be transmitted, which
corresponds to each partitioned area in a storage device included in the remote
management unit. Herein, the predetermined transmission information amount and
transmission cycle are predetermined so that the amount of the information to be
transmitted is reduced and the transmission cycle is shortened as the partitioned area is
close to the boundary line of the movable area when the partitioned area is in the
boundary line of the movable area, and may be determined so that the predetermined
information to be transmitted is reduced and the transmission cycle is shortened as the
partitioned area becomes distant out of the movable area when the partitioned area is out
of the movable area.
[0034] The construction machine generates positional information (that is, current
positional information) of the construction machine and generates at least one piece of
state information and at least one piece of operation information to transmit the
information to the remote management unit. The remote management unit receives the
positional information, the state information, and the operation information (step S3 30).
In the exemplary embodiment, the positional information generated from the
construction machine may be generated through a navigation system included in the
construction machine by using, for example, a signal related to a current position, which
is received from the GPS satellite, but may be generated through various other terrestrial
and satellite position determining systems. Further, information transmitted together
with the positional information may include any information which a remote owner or
manager (alternatively, the remote management unit) needs to efficiently manage the
construction machine, in addition to the state information and the operation information.
In addition, it will be understood by those skilled in the art that the information can be
transmitted from the construction machine to the remote management unit through
various usable mobile communication systems.
[0035] The remote management unit that receives the information including the
positional information from the construction machine judges which area among the
previously partitioned areas the position of the construction machine is included in, on
the basis of the received positional information and transmits a control signal to direct
the predetermined amount of the information to be transmitted and the predetermined
transmission cycle to correspond to the area to which the construction machine belongs,
from the remote management unit to the construction machine (step S340). The
construction machine sets the amount and transmission cycle of information to be
transmitted thereafter and transmits the information to the remote management unit
according to the received control signal (step S3 50).
[0036] Hereinafter, a step of partitioning the movable area and a step of determining
the amount and transmission cycle of the information to be transmitted will be described
in more detail.
[0037] FIG 4 is a configuration diagram showing a movable area of a construction
machine which is partitioned according to an exemplary embodiment of the present
invention. Referring to FIG. 4, the movable area may be partitioned into a first area, a
second area, a third area, and a fourth area. Herein, the first area may be a 'routine
working position' as a state in which that the construction machine is within the
boundary line of the movable area, however, it is not in contact with the boundary line
of the movable area. The second area may be a 'position in which theft may occur' as
a state in which the construction machine is within the boundary line of the movable
area, however, it is in contact with the boundary line of the movable area. The third
area is a 'position in which theft is feared' as a state in which the construction machine
gets out of the boundary of the movable area to be in contact with the boundary line of
the movable area. The fourth area may be a 'position in which theft is certain' as a
state in which the construction machine is also distant from the boundary line of the
movable area while it gets out of the boundary line of the movable area. In the
exemplary embodiment, although the boundary line or the partitioned area of the
movable area has a quadrangle, its shape may be set as a circle, an oval, or a
predetermined shape to be suitable for the owner or manager to manage the construction
machine effectively. Further, in the exemplary embodiment, the movable area is
partitioned into four areas on the basis of the boundary line, but it will be understood by
those skilled in the art that the movable area may be further subdivided according to a
distance from the boundary line of the movable area in some exemplary embodiments.
[0038] A step of predetermining the amount and transmission cycle of the
information to be transmitted in association with transmission of the information from
the construction machine according to the partitioned area will be described in more
detail with reference to FIG. 5. FIG 5 is a diagram showing the relationship between
different data amounts and transmission cycles of transmitted information
corresponding to each partitioned area according to an exemplary embodiment of the
present invention.
[0039] FIG 5(a) shows a case in which the construction machine is positioned in the
first area, which corresponds to the routine working position within the boundary line of
the movable area and in this case, the positional information, the state information, and
the operation information are all transmitted as communication data and the
transmission cycle is set to a cycle T of a predetermined routine case.
[0040] FIG 5(b) shows a case in which the construction machine is close to or in
contact with the boundary line of the movable area, which corresponds to the position in
which theft may occur and in this case, the positional information among the
transmission information is subjected to a transmission state and the data amount of the
transmitted information is reduced by transmitting information other than information
having low priority among at least one pieces of state information and/or at least one
piece of operation information. Meanwhile, by reducing the data amount of the
transmitted information and making the communication cycle be earlier than that of the
first area (in FIG. 5, the cycle is decreased by 1/2 times as compared with FIG. 5(a)), a
frequency to transmit information including the positional information for unit hour is
increased. To this end, the step of predetermining the amount of the information to be
transmitted may include a step of previously determining priorities of at least one piece
of state information or at least one piece of operation information other than the
positional information. Meanwhile, in this case, a transmission coast may maintain
substantially the same level as that of FIG. 5(a) as possible.
[0041] FIG 5(c) shows a case in which theft is feared as the construction machine
gets out of the boundary line of the movable area and theft is feared and in this case,
similarly as the case of FIG. 5(b), the positional information among the transmitted
information maintains the transmission state and information other than state
information and operation information having low priority among at least one piece of
state information and at least one operation information is transmitted, and as a result,
data amount of entire transmitted information are smaller than those of FIG. 5(b).
Meanwhile, the transmission cycle is four times earlier than that of FIG 5(b), and as a
result, the position of the construction machine can be more accurately tracked. In this
case, the transmission cost may be set to maintain substantially the same level as that of
FIG 5(a) or 5(b).
[0042] FIG 5(d) shows a case in which the construction machine gets out of the
boundary line of the movable area to be distant from the boundary line and in this case,
theft may be certain. The communication data is configured by transmitting only
positional information other than both the state information and the operation
information , as a result, the data amount of the entire transmitted information is further
decreased as compared with that of FIG. 5(a), 5(b), or 5(c), but the transmission cycle is
8 times earlier than that of FIG. 5(a), 5(b), or 5(c), and as a result, the position of the
construction machine can be tracked more rapidly and accurately, thereby rapidly taking
action against a theft situation. Even in this case, the transmission cost may be set to
maintain substantially the same level as that of FIG. 5(a), 5(b), or 5(c).
[0043] In the above-mentioned exemplary embodiment, the movable area is
partitioned into four areas according to the distance from the boundary line of the
movable area, but the four areas may be further subdivided as necessary and used by
functionalization in proportion to the distance from the boundary line of the movable
area. Further, the fourth area described above may be set as an area other than the first,
second, and third areas, which exist outside the work allowance area.
[0044] Further, in the above-mentioned exemplary embodiment, the movable area is
partitioned based on the distance from the boundary line thereof, but the movable area
may be subdivided based on a distance from a central point of the movable area. That
is, by partitioning the area based on the distance from the central point of the movable
area according to a movement direction of the construction machine, an amount of
transmitted information other than the positional information is reduced and the
transmission cycle thereof is further shortened as the construction machine is distant
from the central point.
[0045] FIG 6 is a diagram showing the relationship between a transmitted
information amount and a transmission cycle with the position of a construction
machine according to an exemplary embodiment of the present invention. FIG. 6
shows ratios, transmission cycle, and transmission costs of state information and
operation information with respect to positional information in an amount of
information to be transmitted (alternatively, a configuration of transmitted information),
which depends on a position. In FIG. 6, a functional relationship among the
transmission cycle T, a ratio R of the positional information (herein, R represents the
positional information/the entire transmitted information), a distance AL from a
boundary line of the work allowance area to the construction machine (however, a
negative (-) figure within the work allowance area), and the transmission cost P may be
shown below.
[0046] Before the construction machine deviates from point A, transmission can be
performed with a configuration of transmitted information having a predetermined
positional information ratio Rmin and a transmission cycle Tmax. In this case (AL <
A), there may be defined as the transmission cycle, T = T_max, for the positional
information ratio, R = Rmin, and the transmission cost, P = Pfix.
[0047] Meanwhile, before the construction machine gets out of point A and reaches
point B, the ratio of the positional information to the entire transmitted information is
high in direct proportion to the position of the construction machine and the
transmission cycle is shortened in inverse proportion to the distance AL from the
boundary line of the movable area to the construction machine (however, the negative (-
) figure within the boundary line of the movable area). At this time, when the
construction machine gets out of a point where AL is 0 (when the construction machine
is on the boundary line of the movable area) and breaks away from the work allowance
area, a theft possibility may be warned to the owner or manager (remote management
unit). Functionalization thereof is as follows.
[0048] In the case of A< ? L T2 > T3 > T4 (wherein Tn represents a transmission cycle in an n-th
area)
[0059] R1 < R2 < R3 < R4 (wherein Rn represents a ratio between a total
transmitted information amount and a positional information amount = the positional
information amount / the total transmitted information amount in the n-th area)
[0060] Meanwhile, in the exemplary embodiment, as shown in the fourth area of FIG.
6, R4 = 1. The fourth area is the area in which theft of the construction machine is
certain and in this case, since the remote management unit may not require the state
information or operation information of the construction machine, positional
information closer to the real time is received by setting the transmission cycle to be
shorter instead of setting only the positional information of the construction machine to
be received.
[0061] Further, in the exemplary embodiment, when the construction machine is at
the 'position in which theft is feared' or at the 'position in which theft is certain' the
remote management unit may be configured to notify theft possibility alarm or theft
alarm.
[0062] FIG. 7 is a flowchart showing steps of controlling a transmitted information
amount and a transmission cycle according to an exemplary embodiment of the present
invention. According to the exemplary embodiment, the remote management unit
judges which area the current position of the construction machine belongs to (steps
S606, S608, and S610) on the basis of the received positional information and the
remote management unit may transmit a control signal indicating a predetermined
amount of information to be transmitted and a transmission cycle, which correspond to
the area to which the construction machine belongs, to the construction machine (step
S614).
[0063] FIG. 8 is a block diagram showing information transmitting communication
apparatus 700 of a construction machine and a control signal generating unit 752 of a
remote management unit 750 according to an exemplary embodiment of the present
invention.
[0064] According to the exemplary embodiment, the information transmitting
communication apparatus 700 of the construction machine may include a controller 710
including a transmitted information amount controlling unit 711 and a transmission
cycle controlling unit 712, a positional information generating unit 714, a storage unit
715, a state/operation information generating unit 716, and a wireless communication
unit 717. In order to transmit the positional information, the state information, and the
operation information to the remote management unit, the information transmitting
communication apparatus generates the corresponding information and stores the
information in the storage unit through the positional information generating unit and
the state/operation information generating unit. The controller 710 transmits the
information such as the positional information, and the like through the wireless

communication unit 717 to the remote management unit according to the predetermined
amount of the information to be transmitted and the transmission cycle. The remote
management unit may include a judgment unit 754 judging an area in which the
construction machine is positioned among previously partitioned areas on the basis of
the positional information received through the wireless communication unit 753, a
setting unit 751 setting the amount of the information to be transmitted and the
transmission cycle and notifying the predetermined amount of the information to be
transmitted and the transmission cycle on the basis of a result of the judgment unit, and
a control signal generating unit 752 generating a control signal representing the
transmitted information amount and the transmission cycle received by the setting unit
and transmitting the generated control signal to the construction machine.
[0065] As described above, although the present invention has been described on the
basis of the exemplary embodiments, it will be understood by those skilled in the art
that changes can be made without departing from the spirit and scope of the present
invention. That is, since the present invention can be changed within the appended
claims, the present invention should not be regarded to be limited to the exemplary
embodiments.
[Industrial Applicability]
[0066] The present invention relates to a communication method for monitoring the
positions of a construction machine and can be applied to prevent theft of the
construction machine by monitoring the position of the construction machine.
[CLAIMS]
1. A commumcation method for monitoring the position of a construction
machine, the method comprising:
generating positional information of the construction machine and at least one
piece of state information and at least one piece of operation information associated
with the construction machine in the construction machine; and
transmitting the generated information to a remote management unit which is
positioned in a remote area from the construction machine by using a commumcation
means,
wherein the remote management unit partitions an area where the construction
machine is movable and previously determines the amount and transmission cycle of
information to be transmitted from the construction machine in accordance with the
partitioned area, and
the amount of information to be transmitted other than the positional
information from the construction machine is reduced as the construction machine is
distant out of a boundary line of the movable area, on the basis of the positional
information received from the construction machine.
2. The communication method for monitoring the position of a construction
machine according to claim 1, wherein the transmission cycle from the construction
machine is shortened as the construction machine is distant out of the boundary line of
the movable area, on the basis of the positional information received from the
construction machine.
3. The commumcation method for monitoring the position of a construction

machine according to claim 1, wherein the amount of the information other than the
positional information from the construction machine is reduced and the transmission
cycle thereof is shortened as the construction machine is close to the boundary line
within the movable area, and the amount of the information other than the positional
information from the construction machine is further reduced and the transmission cycle
thereof is further shortened as the construction machine is distant out of the boundary
line of the movable area, on the basis of the positional information received from the
construction machine.
4. The communication method for monitoring the position of a construction
machine according to claim 1, wherein in the partitioning of the area where the
construction machine is movable, the area is at least partitioned into a first area, a
second area, a third area, and a fourth area in a direction distant from the center of the
movable area and the first area and the second area are set within the boundary line of
the movable area and in this case, the second area is set to contact the boundary line of
the movable area, and the third area and the fourth area are set out of the boundary line
of the movable area and in this case, the third area is set to contact the boundary line of
the movable area, and
the transmission cycle is determined to be T1 > T2 > T3 > T4 (wherein Tn
represents a transmission cycle in an n-th area) and the amount of the information to be
transmitted is determined to be R1 < R2 < R3 < R4 = 1 (wherein Rn represents a ratio
of positional information amount to total transmitted information amount in the n-th
area), in accordance with the partitioned area.

The present invention relates to a communication method for monitoring the
position of a construction machine. The communication method according to the
present invention includes: generating positional information of the construction
machine and at least one piece of state information and at least one piece of operation
information associated with the construction machine in the construction machine; and
transmitting the generated information to a remote management unit which is positioned
in a remote area from the construction machine by using a communication means,
wherein the remote management unit partitions an area where the construction machine
is movable and previously determines the amount and transmission cycle of information
to be transmitted from the construction machine in accordance with the partitioned area,
and the amount of information to be transmitted other than the positional information
from the construction machine is reduced as the construction machine is distant out of a
boundary line of the movable area, on the basis of the positional information received
from the construction machine. According to the present invention, by controlling the
amount and communication cycle of information to be transmitted according to a
distance between the boundary line of the movable area and the construction machine,
the more accurate positional information can be provided in a theft danger state or a
theft state while keeping power consumption.