JP2011185891A - Mobile terminal and positioning method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal reduced in the power consumption and traffic load, and a positioning method for the mobile terminal. <P>SOLUTION: Based on positional information of artificial satellites, artificial satellites whose elevation angle from the present position of the mobile terminal 40 is a threshold X or more are specified. Of the specified artificial satellites, the number of artificial satellites where the elapsed time from TOE is within a threshold Y is counted. It is determined whether the number of counted artificial satellites is a threshold Z or more. If the determination is negative, the positional information and TOE are requested and received from a positional information providing device 30, a signal including the present time information transmitted from the artificial satellites is received, and the position of the mobile terminal 40 is measured based on the received positional information and the present time information included in the signal. If the determination is positive, the positional information and TOE are not requested for the positional information providing device 30, a signal including the present time information transmitted from the artificial satellites is received, and the position of the mobile terminal 40 is measured based on the positional information stored in a storage section 90 and the present time information included in the signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a mobile terminal and a mobile terminal positioning method.

  As a means for measuring the current position on the earth, a global positioning system (hereinafter referred to as GPS) is used. In GPS positioning, the ground GPS positioning device receives the time information and satellite position information transmitted by multiple GPS satellites orbiting the earth, and measures each of the distances between the multiple GPS satellites and the GPS positioning device. Is done by doing.

  The satellite position information transmitted by each satellite includes an ephemeris indicating detailed position information for each satellite and an almanac indicating schematic position information of all satellites. Each satellite constantly transmits its ephemeris and almanac common to all satellites.

As a GPS positioning method, the GPS positioning device obtains both time information and satellite position information from GPS satellites and performs positioning, and necessary position information is not obtained from GPS satellites. There is assisted GPS positioning (assisted GPS positioning) in which positioning is obtained from the network, and calculation necessary for positioning is performed by a server (assist server) other than the GPS positioning device and the result is received ( For example, Patent Document 1).
In autonomous GPS positioning, in order for the GPS positioning device to acquire satellite position information, it is necessary to decode a signal transmitted by a GPS satellite, which takes time. In the assisted GPS positioning, the GPS positioning device only needs to receive the decoded satellite position information stored in the assist server via the network, so that the time required for positioning can be shortened.
Further, in order to decode the signal from the GPS satellite and acquire the satellite position information, a strong electric field environment of the GPS signal (the level of the received GPS signal is high) is required. Autonomous GPS positioning cannot be performed in a weak electric field environment where satellite position information cannot be acquired. On the other hand, in the assist type GPS positioning, since the satellite position information can be received via the network even in a weak electric field environment, the positioning is possible. That is, as compared with autonomous GPS positioning, the assist type GPS positioning can widen the positioning possible area.

JP 2005-147720 A

  However, in order to perform assist type GPS positioning, the GPS positioning device needs to receive satellite position information from the assist server separately from the time information transmitted from the GPS satellite. Therefore, the power consumption required for assist type GPS positioning is larger than the power consumption required for autonomous GPS positioning. This means that when the GPS positioning device is a mobile terminal such as a mobile phone, the operating time of the mobile terminal is limited, or it is necessary to equip a huge battery for supplying necessary power. Is a problem. In addition, since the satellite position information is received by the GPS satellite positioning device via the network, there is a problem that traffic on the network increases.

  Therefore, the present invention provides a mobile terminal and a mobile terminal positioning method that reduce power consumption and network traffic load while ensuring a short positioning time and a wide positioning area.

  A mobile terminal according to the present invention includes a satellite receiver that receives a signal including current time information timed by the artificial satellites transmitted from a plurality of artificial satellites, and a positional information providing device that provides positional information of the plurality of artificial satellites A mobile communication network communication unit that receives position information of an artificial satellite and position information time information corresponding to the position information from the mobile communication network, and the mobile communication network communication unit receives the position information and the position information time information. A plurality of satellites each having an elevation angle from the current position of the mobile terminal equal to or greater than a first threshold based on the position information and a storage unit that stores the position information and the position information time information each time The number of artificial satellites whose elapsed time from the position information time information is within a second threshold among the plurality of artificial satellites specified by the artificial satellite specifying unit and the artificial satellite specifying unit A satellite counting unit that counts, a determination unit that determines whether the count value counted by the satellite counting unit is equal to or greater than a third threshold, and a positioning unit that measures the position of the mobile terminal, When the determination by the determination unit is negative, the mobile communication network communication unit requests the position information and the position information time information from the position information providing device to request the position information and the position information time. Information is received, the satellite receiving unit receives signals transmitted from the plurality of artificial satellites, and the positioning unit includes the positional information received and requested by the mobile communication network communication unit and the current signal When the position of the mobile terminal is measured based on the time information and the determination by the determination unit is affirmative, the mobile communication network communication unit transmits the position information and the position information to the position information providing device. Need time information The satellite reception unit receives signals transmitted from the plurality of artificial satellites, and the positioning unit is based on the position information stored in the storage unit and the current time information included in the signal. Measure the position of the mobile terminal.

  According to the positioning method of the mobile terminal according to the present invention, the position information providing apparatus that provides the position information of a plurality of satellites receives the position information of the satellites and the position information time information corresponding to these position information via the mobile communication network. Receiving the position information and the position information time information each time the position information and the position information time information are received, and storing the position information and the position information time information in a storage unit, and based on the position information, Identifying a plurality of artificial satellites each having an elevation angle equal to or greater than a first threshold, and among the plurality of artificial satellites identified as having an elevation angle equal to or greater than a first threshold, an elapsed time from the position information time information Counting the number of artificial satellites that are within the second threshold and whether or not the number of artificial satellites whose elapsed time from the counted position information time information is within the second threshold is greater than or equal to the third threshold The And determining and receiving the position information and the position information time information by requesting the position information and the position information time information from the position information providing device, if the determination is negative, Based on the position information received by requesting the position information providing apparatus and the current time information included in the signal received from the plurality of artificial satellites and including the current time information measured by the artificial satellites. If the determination of the position of the mobile terminal and the determination is affirmative, the position information and the position information time information are not requested to the position information providing device, and the plurality of artificial satellites are not requested. The mobile terminal receives the signal including the current time information timed by the artificial satellite transmitted, and based on the position information stored in the storage unit and the current time information included in the signal The positioning of position.

  Thus, according to the present invention, by calculating the elevation angle of the artificial satellite based on the position information of the artificial satellite previously stored in the storage unit, the artificial satellite that can be used for positioning is specified, and the storage unit By calculating the elapsed time from the position information time information stored in the position information, an artificial satellite that can be used for positioning is specified, a determination is made, and the positioning operation is changed. Therefore, according to the present invention, compared with the case where the positioning operation is changed by determining that the signal from the artificial satellite cannot be received (the artificial satellite cannot be tracked) or the signal from the artificial satellite is weak. The operation of receiving the signal from the receiver and the operation of determining the received signal can be omitted. Therefore, power consumption can be reduced and the positioning operation can be changed more quickly. Further, since the number of artificial satellites that can be used for positioning is determined based on both the elevation angle and the elapsed time, the determination becomes more reliable.

  According to the present invention, if the determination is affirmative, that is, if the number of satellites that can be used for positioning is greater than or equal to the third threshold, the mobile terminal has already received the position information and the position information time information without receiving it. If positioning is performed using the stored location information and the determination is negative, that is, if the number of satellites available for positioning is less than the third threshold, the mobile terminal Receive information and perform positioning. Therefore, the frequency with which a mobile terminal receives location information and location information time information can be lowered. Therefore, compared with the case where the mobile terminal does not store the position information and the position information time information and acquires the position information and the position information time information every time the positioning is performed, the required power consumption, the required time, and the network traffic load are reduced. Can be reduced.

  If the determination is affirmative, positioning can be performed even if the position information and the position information time information cannot be received. Therefore, when it is necessary to acquire the position information and the position information time information for each positioning. In comparison, the positioning area can be widened.

  As described above, according to the present invention, positioning is mainly performed without receiving position information and position information time information from the position information providing apparatus, and position information and position information time information are received from the position information providing apparatus. In positioning of a mobile terminal dependent on positioning, it is possible to reduce power consumption and network traffic load while securing a short positioning time and a wide positioning area.

It is the schematic which shows the whole communication system with which the mobile terminal which concerns on embodiment of this invention is used. It is a block diagram which shows the structure of the said mobile terminal. It is a flowchart which shows operation | movement of the said mobile terminal.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the entire communication system in which the mobile terminal according to the embodiment is used includes a mobile communication network 10 and a plurality of mobile terminals 40 that can communicate with the mobile communication network 10. The mobile communication network 10 includes a plurality of base stations 12, and the base station 12 communicates with mobile terminals 40 in the cell of the base station.

  Each mobile terminal 40 is, for example, a mobile phone handset or another terminal that can use a mobile communication network. Each mobile terminal 40 receives, from a plurality of (for example, four) GPS satellites 20, GPS signals including current time information timed by the GPS satellites 20 and GPS satellite position information (ephemeris). By specifying the distance between each of the GPS satellites 20 and the mobile terminal 40 based on the ephemeris, the current position of the mobile terminal 40 itself can be specified. Each mobile terminal 40 receives current time information from the GPS satellite 20, receives an ephemeris from a position information providing device 30 to be described later, and specifies the distance between each GPS satellite 20 and the mobile terminal 40, thereby moving the mobile terminal 40. It is also possible to specify the current position of the terminal 40 itself.

  Here, the GPS satellite position information (ephemeris) includes time information (Time Of Ephemeris, TOE) that serves as a reference for the position information of the GPS satellites. In addition, TOE may be described. Ephemeris and TOE are determined for each GPS satellite.

  A location information providing device 30 is connected directly or indirectly to the mobile communication network 10. For example, the location information providing device 30 may communicate with one base station 12 of the mobile communication network 10 wirelessly. Alternatively, the location information providing apparatus 30 may be connected to another network connected to the mobile communication network 10 by wire.

  The location information providing device 30 provides the ephemeris and TOE necessary for the mobile terminal 40 to specify the current location of the mobile terminal 40 itself. As will be described later, the location information providing apparatus 30 transmits the ephemeris and the TOE to the mobile terminal 40 via the mobile communication network in response to a request from the mobile terminal 40. The mobile terminal 40 stores the received ephemeris and TOE.

As shown in FIG. 2, the mobile terminal 40 includes a satellite receiving unit 50, a satellite receiving antenna 52, a mobile communication network communication unit 60, a mobile communication network communication antenna 62, an input unit 70, a storage unit 90, and a CPU (Central Processing Unit). 100.
Under the control of the CPU 100, the satellite receiving unit 50 receives and analyzes the GPS signal transmitted by the GPS satellite 20 by the satellite receiving antenna 52, and outputs the current time information, ephemeris, and the like included in the GPS signal to the CPU 100. The satellite receiver 50 can obtain only the current time information by analyzing the received GPS signal, or can obtain the current time information and the ephemeris.

The mobile communication network communication unit 60 receives a signal transmitted from another communication device by the mobile communication network communication antenna 62 via the mobile communication network 10, and processes the received signal under the control of the CPU 100. For example, the ephemeris and the TOE transmitted by the position information providing device 30 are received by the mobile communication network communication antenna 62 via the mobile communication network 10 and transferred to the CPU 100.
In addition, the mobile communication network communication unit 60 transmits a signal to another communication device (for example, the position information providing device 30) through the mobile communication network 10 by the mobile communication network communication antenna 62 under the control of the CPU 100. .

The input unit 70 is, for example, a plurality of buttons or a keyboard, and is operated by a user of the mobile terminal 40 and used for inputting an instruction to the mobile terminal 40 from the user.
The storage unit 90 stores the ephemeris and the TOE in the storage unit 90 every time the mobile communication network communication unit 60 receives the ephemeris and the TOE. In addition, the storage unit 90 stores the current position of the mobile terminal 40.

Based on each of the ephemeris corresponding to the plurality of GPS satellites 20 stored in the storage unit 90, the artificial satellite specifying unit 102 of the CPU 100 selects the GPS satellites 20 whose elevation angle from the current position of the mobile terminal 40 is equal to or greater than the threshold value X. Identify. Here, the threshold value X may be set to 0 degrees so that all GPS satellites existing on the horizon when viewed from the mobile terminal 40 are targeted, or a GPS signal having a lot of noise from the GPS satellites 20 at a low elevation angle. For example, 15 degrees or another value may be used.
The artificial satellite counting unit 104 of the CPU 100 includes a plurality of GPS satellites identified by the artificial satellite identification unit 102 as being equal to or greater than the threshold value X based on each of the TOEs corresponding to the plurality of GPS satellites 20 stored in the storage unit 90. 20, the number of GPS satellites 20 whose elapsed time from the TOE is within the threshold Y is counted. Here, the threshold value Y may be 1.5 hours after which the error between the position indicated by the ephemeris and the actual position of the GPS satellite 20 becomes significant, or may be another value.
The determination unit 106 of the CPU 100 determines whether or not the number of GPS satellites 20 that have been counted by the artificial satellite counting unit 104 as having elapsed from the TOE within the threshold Y is greater than or equal to the threshold Z. Here, according to the experimental result of examining the positioning accuracy and positioning time when the number of GPS satellites 20 is changed, it is preferable that the threshold value Z is 7.
The positioning unit 108 of the CPU 100 measures the current position of the mobile terminal 40 according to the determination result of the determination unit 106.

  As described above, based on the ephemeris and TOE stored in the storage unit 90, the number of GPS satellites 20 that can be used to determine the current position of the mobile terminal 40 can be counted and determined. Therefore, compared to the case where the number of GPS satellites 20 that can be used for positioning is counted and determined by receiving GPS signals actually transmitted by the GPS satellites 20 and determining whether or not the signals can be received or measuring the reception quality. The required time and power consumption can be reduced.

  Next, the operation of the mobile terminal 40 will be described with reference to the flowchart of FIG. This operation is realized by the CPU 100 executing a computer program corresponding to the flowchart of FIG. This operation is performed when a user of the mobile terminal 40 requests GPS positioning using the input unit 70, or a periodic automatic measurement function program for periodically acquiring the current position of the mobile terminal 40 (for example, The program executed on the CPU 100 of the mobile terminal 40, such as a program for a service provided by T. T. Docomo under the name “Auto GPS”, is executed when the GPS positioning is requested.

  In step S1, the artificial satellite specifying unit 102 specifies the GPS satellite 20 whose elevation angle from the current position of the mobile terminal 40 is equal to or greater than the threshold value X as described above. Specifically, the artificial satellite specifying unit 102 reads the ephemeris corresponding to each of the plurality of GPS satellites 20 and the current position of the mobile terminal 40 from the storage unit 90, and based on each of the ephemeris and the current position of the mobile terminal 40. The elevation angle of each GPS satellite 20 is calculated, and the GPS satellite 20 whose elevation angle is equal to or greater than the threshold value X is specified.

In step S2, the artificial satellite counting unit 104 calculates the number of GPS satellites 20 whose elapsed time from the TOE is within the threshold value Y for the plurality of GPS satellites 20 whose elevation angle is specified to be equal to or greater than the threshold value X as described above. Count. Specifically, the satellite counting unit 104 reads the TOE corresponding to the GPS satellite 20 identified in step S1 from the storage unit 90, and calculates the elapsed time with respect to the internal current time of the mobile terminal 40 from each of the TOEs. The number of GPS satellites 20 whose elapsed time from the TOE is within the threshold Y is counted.
In this example, the artificial satellite counting unit 104 calculates the elapsed time from the TOE when counting, but as a modification, the CPU 100 calculates the difference between the TOE and the internal current time of the mobile terminal 40 in advance. It may be stored in the storage unit 90, and the artificial satellite counting unit 104 may count the number of GPS satellites 20 whose elapsed time from the TOE is within the threshold Y based on the stored difference. As another modification, the CPU 100 operates as a timer, deletes the ephemeris and the TOE of the GPS satellite 20 whose elapsed time from the TOE has exceeded the threshold Y from the storage unit 90, and the storage unit 90 has elapsed since the TOE. Only the ephemeris and TOE of the GPS satellite 20 whose time is within the threshold Y may be stored. Further, instead of deleting the ephemeris and TOE of the GPS satellite 20 whose elapsed time from the TOE has exceeded the threshold value Y from the storage unit 90, a flag not used for determination may be set.

In step S <b> 3, the determination unit 106 determines whether the number of the GPS satellites 20 whose elapsed time from the TOE is within the threshold Y among the GPS satellites 20 whose elevation angle is specified to be the threshold X or more is the threshold Z or more. Determine whether or not.
If the determination is affirmative, that is, the number of GPS satellites 20 whose elapsed time from the TOE is within the threshold Y among the GPS satellites 20 whose elevation angle is specified to be the threshold X or more is the threshold Z or more. The process proceeds to step S4.
If the determination is negative, that is, the number of GPS satellites 20 whose elapsed time from the TOE is within the threshold Y among the GPS satellites 20 whose elevation angle is specified to be greater than or equal to the threshold X is less than the threshold Z, The process proceeds to step S6.

  In step S4, the CPU 100 performs control so that the satellite receiver 50 receives and analyzes each of the GPS signals transmitted by the plurality of GPS satellites 20. The satellite receiver 50 analyzes a plurality of GPS signals received by the satellite receiving antenna 52, calculates current time information corresponding to each of the GPS satellites 20, and outputs the current time information to the CPU 100.

  In step S <b> 5, the positioning unit 108 reads ephemeris corresponding to the plurality of GPS satellites 20 stored in the storage unit 90. Then, the position of the mobile terminal 40 is measured based on the current time information of the GPS satellite output from the satellite receiver 50 in step S 4 and the ephemeris read from the storage unit 90, and the measured current position is stored in the storage unit 90. Remember. Thereafter, the positioning operation ends.

  On the other hand, in step S <b> 6, the CPU 100 controls the mobile communication network communication unit 60 to transmit the ephemeris and TOE transmission requests to the position information providing apparatus 30. The mobile communication network communication unit 60 transmits a signal requesting transmission of the ephemeris and the TOE to the position information providing device 30 via the mobile communication network 10 by the mobile communication network communication antenna 62.

  In step S7, the CPU 100 controls the mobile communication network communication unit 60 to receive the ephemeris and the TOE transmitted by the location information providing device 30 in accordance with the request in step S6. The mobile communication network communication unit 60 receives the ephemeris and the TOE transmitted from the position information providing device 30 by the mobile communication network communication antenna 62 and transfers them to the CPU 100. The CPU 100 stores the ephemeris and TOE transferred by the mobile communication network communication unit 60 in the storage unit 90.

  In step S8, the CPU 100 performs control so that the satellite receiver 50 receives and analyzes each of the GPS signals transmitted by the plurality of GPS satellites 20. The satellite receiver 50 analyzes a plurality of GPS signals received by the satellite receiving antenna 52, calculates current time information corresponding to each of the GPS satellites 20, and outputs the current time information to the CPU 100.

  In step S9, the positioning unit 108 determines the position of the mobile terminal 40 based on the current time information of the GPS satellite output from the satellite receiver 50 in step S8 and the ephemeris received by the mobile communication network communication unit 60 in step S7. Positioning is performed, and the current position thus measured is stored in the storage unit 90. Thereafter, the positioning operation ends.

As described above, according to this embodiment, in steps S4 and S5, which are positioning operations after a positive determination is made in step S3, the mobile terminal 40 sends the ephemeris and TOE to the location information providing device 30. Do not request to send. On the other hand, in steps S6 to S9, which are positioning operations after a negative determination is made in step S3, the mobile terminal 40 requests the location information providing device 30 to transmit the ephemeris and the TOE.
That is, when the number of GPS satellites 20 that can be used for positioning is equal to or greater than the threshold value Z, there is no need to newly receive an ephemeris, so positioning is performed using the ephemeris stored in the storage unit 90 in the past. Do. When the number of GPS satellites 20 that can be used for positioning is less than the threshold value Z, it is necessary to newly receive an ephemeris. Therefore, the ephemeris is received from the position information providing device 30, and the received ephemeris is used. To perform positioning (assist type GPS positioning). By selecting the positioning means in this way, it is not necessary to receive the ephemeris from the position information providing device 30 for each positioning as in the normal assist type GPS positioning, so that the positioning time can be shortened, Power consumption can be reduced, and the traffic load on the mobile communication network can be reduced.

  Further, when the number of GPS satellites 20 that can be used for positioning is equal to or greater than the threshold value Z, there is no need to access the mobile communication network in order to receive the ephemeris, so that the mobile terminal 40 accesses the mobile communication network. The current position of the mobile terminal 40 can be measured even in a place where it cannot be done.

  In addition, since the positioning means is selected based on the number of GPS satellites 20 that can be used for positioning, when the elapsed time since the most recent assist type GPS positioning is more than a predetermined time, the assist type GPS Compared with the selection of positioning means using a timer that performs positioning, otherwise performs GPS positioning using the ephemeris stored in the storage unit 90 in the past, according to the number of available GPS satellites 20 It is possible to select a dynamic positioning means.

  Further, the elevation angle of the GPS satellite 20 is calculated based on the ephemeris stored in the storage unit 90, the elapsed time from the TOE stored in the storage unit 90 is calculated, and the number of GPS satellites 20 that can be used for positioning is calculated. By counting, it is determined whether to perform GPS positioning using the ephemeris stored in the storage unit 90 in the past or to perform assist type GPS positioning. Therefore, the GPS satellite 20 cannot be tracked or the signal from the GPS satellite 20 is Compared with the case of determining which positioning is to be performed because the reception level is low, the operation of receiving a signal from the GPS satellite 20 for determination can be omitted. Therefore, power consumption can be reduced, and at the same time, a quick determination is possible. Further, since the validity of the GPS satellite 20 is determined from both the elevation angle and the elapsed time from the TOE, more reliable determination is possible.

  While the embodiment according to the present invention has been described above, the following modifications are also within the scope of the present invention.

  In the above-described embodiment, the positioning unit 108 measures the current position of the mobile terminal 40 based on the current time information transmitted from the plurality of GPS satellites 20 and the ephemeris corresponding to the plurality of GPS satellites 20 (step S5, step S5). S9). As another embodiment, the positioning unit 108 includes current time information transmitted from a plurality of GPS satellites 20, ephemeris corresponding to the GPS satellites 20, and base stations 12 transmitted from one or more base stations 12. The current position of the mobile terminal 40 may be measured based on a signal indicating the position information.

  In the above-described embodiment, the positioning operation is started by a user instruction or a request from a program executed by the CPU 100. However, in another embodiment, the mobile terminal 40 is changed from the current cell or sector to another A positioning operation may be initiated when moving to a cell or sector. That is, the positioning operation of the mobile terminal 40 may be started when the inter-cell handover or the inter-sector handover starts or ends.

  In the above-described embodiment, the elevation angle of the GPS satellite 20 is calculated using the ephemeris, but the elevation angle may be calculated using an almanac instead of the ephemeris. Since the almanac has a long effective period, the elevation angle can be calculated even for the GPS satellite 20 in which no valid ephemeris is stored in the storage unit 90 and only the almanac is stored.

In the above-described embodiment, the mobile terminal 40 has one CPU 100. However, as another embodiment, the mobile terminal 40 may include a plurality of CPUs having functions of the artificial satellite identification unit 102, the artificial satellite counting unit 104, the determination unit 106, and the positioning unit 108.
Furthermore, each function executed by the CPU 100 may be executed by hardware instead of the CPU, or may be executed by a programmable logic device such as an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor). . The CPU of the GPS chip may execute each function.

  The above-described modifications may be combined as long as there is no contradiction.

DESCRIPTION OF SYMBOLS 10 ... Mobile communication network, 20 ... GPS satellite, 30 ... Location information provision apparatus, 40 ... Mobile terminal, 50 ... Satellite receiving part, 60 ... Mobile communication network communication part, 70 ... Input part, 90 ... Memory | storage part, 100 ... CPU

Claims (2)

A satellite receiver for receiving a signal including current time information timed by the artificial satellites transmitted from a plurality of artificial satellites;
A mobile communication network communication unit that receives position information of artificial satellites and position information time information corresponding to these position information from a position information providing device that provides position information of a plurality of artificial satellites;
A storage unit for storing the position information and the position information time information each time the mobile communication network communication unit receives the position information and the position information time information;
Based on the position information, an artificial satellite identifying unit that identifies a plurality of artificial satellites each having an elevation angle equal to or greater than a first threshold from the current position of the mobile terminal;
Among a plurality of artificial satellites specified by the artificial satellite specifying unit, an artificial satellite counting unit that counts the number of artificial satellites whose elapsed time from the position information time information is within a second threshold;
A determination unit that determines whether the count value counted by the artificial satellite counting unit is equal to or greater than a third threshold;
A positioning unit that measures the position of the mobile terminal,
If the determination by the determination unit is negative, the mobile communication network communication unit requests the position information and the position information time information from the position information providing device to request the position information and the position information. Time information is received, the satellite receiving unit receives signals transmitted from the plurality of artificial satellites, and the positioning unit includes the positional information and the signal received as requested by the mobile communication network communication unit Measure the location of the mobile terminal based on the current time information,
If the determination by the determination unit is positive, the mobile communication network communication unit does not request the position information and the position information time information from the position information providing device, and the satellite reception unit Receiving the signals transmitted from the plurality of artificial satellites, and the positioning unit measures the position of the mobile terminal based on the position information stored in the storage unit and the current time information included in the signal. Feature mobile terminal. A positioning method in a mobile terminal,
Receiving position information of artificial satellites and position information time information corresponding to these position information from a position information providing apparatus that provides position information of a plurality of artificial satellites;
Storing the position information and the position information time information in a storage unit every time the position information and the position information time information are received;
Identifying a plurality of artificial satellites each having an elevation angle greater than or equal to a first threshold from the current position of the mobile terminal based on the position information;
Counting the number of artificial satellites whose elapsed time from the position information time information is within a second threshold among the plurality of artificial satellites identified as having an elevation angle equal to or greater than a first threshold;
Determining whether the number of artificial satellites whose elapsed time from the counted position information time information is within a second threshold is greater than or equal to a third threshold;
When the determination is negative, the position information providing apparatus requests the position information and the position information time information to receive the position information and the position information time information, and the plurality of artificial satellites The position of the mobile terminal is received based on the position information received by requesting the position information providing apparatus and the current time information included in the signal. Positioning and
If the determination is affirmative, the current time measured by the artificial satellites transmitted from the plurality of artificial satellites without requesting the positional information providing apparatus and the positional information time information. A positioning method for a mobile terminal, comprising: receiving a signal including information; and positioning the position of the mobile terminal based on the position information stored in the storage unit and the current time information included in the signal.

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