JP2010130249A - Mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal that achieves improvement in accuracy of GPS positioning. <P>SOLUTION: A mobile telephone 1 includes: a communication control part 31 for executing position registration by any one of a plurality of communication systems; and a CPU 30 that executes single-point positioning processing, in which a GPS signal is received so as to specify the current location by operation from the GPS signal, and auxiliary positioning processing in which a GPS signal is received so as to specify the current location on the basis of the GPS signal and information obtained by the communication control part 31 via a using communication system. If there is a difference, exceeding a first threshold, between the positioning results of both the single-point positioning processing and the auxiliary positioning processing when executing positioning while executing the position registration by a first communication system, the CPU 30 executes the auxiliary positioning processing by using a second communication system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile terminal capable of GPS positioning.

  2. Description of the Related Art Conventionally, GPS (Global Positioning System) that calculates latitude, longitude, and altitude based on the delivery time of a signal from an artificial satellite is used as a means for measuring the position of a user in a portable terminal or the like.

In such a situation, various proposals have been made to improve the convenience of the system. For example, Patent Document 1 shows that GPS positioning is assisted by using network communication.
Japanese translation of PCT publication No. 2002-522793

  However, when the positioning result is obtained based on communication with the base station, there is a possibility that the positioning accuracy may be lowered if the base station becomes far away due to movement of the mobile terminal. In particular, in the case of a communication system using a high frequency band with high straightness, or when the installation density of base stations is low, the distance from the mobile terminal is often increased, and the positioning accuracy is likely to be lowered. Therefore, highly accurate GPS positioning is always required.

  An object of this invention is to provide the portable terminal which can improve the precision of GPS positioning.

  The mobile terminal according to the present invention receives a radio communication unit that registers a position in any of a plurality of communication systems, a GPS signal, a single positioning process that identifies a current location by calculation from the GPS signal, and a GPS signal And a control unit capable of executing an auxiliary positioning process that identifies a current location based on the GPS signal and information obtained by the wireless communication unit via a communication system in use, and the control unit When positioning is performed with the position registered in the first communication system, if there is an opening exceeding the first threshold in the positioning results of both the single positioning process and the auxiliary positioning process. The auxiliary positioning process is performed using the second communication system.

  Moreover, it is preferable that the first communication system is a communication system used in a base station having a lower density of installation than the second communication system.

  The first communication system is preferably in a higher frequency band than the second communication system.

  Further, the wireless communication unit obtains position information of a base station via the communication system in use, and the control unit obtains a previous positioning result when performing positioning continuously by the auxiliary positioning process. When the distance from the base station position information exceeds a second threshold, it is preferable to extend the search time for the satellite in the auxiliary positioning process.

  Further, as a result of extending the search time of the satellite, the control unit captures only 3 or less satellites, and when the difference between the previous positioning result and the current positioning result exceeds a third threshold, It is preferable to perform the auxiliary positioning process using a second communication system.

  ADVANTAGE OF THE INVENTION According to this invention, the precision of GPS positioning can be improved in a portable terminal.

  Hereinafter, an example of a preferred embodiment of the present invention will be described. In addition, although a mobile telephone is demonstrated as an example of the portable terminal of this invention, it is not restricted to this. For example, the present invention can be applied to various portable terminals such as a PHS (Personal Handyphone System) and a PDA (Personal Digital Assistant).

  FIG. 1 is an external perspective view of a mobile phone 1 (mobile terminal) according to the present embodiment. FIG. 1 shows a so-called foldable mobile phone, but the mobile phone according to the present invention is not limited to this. For example, a sliding type in which one casing is slid in one direction from a state in which both casings are overlapped, or a rotary type in which one casing is rotated around an axis along the overlapping direction ( Turn type), or a type (straight type) in which the operation unit and the display unit are arranged in one housing and does not have a connecting unit.

  The mobile phone 1 includes an operation unit side body 2 and a display unit side body 3. The operation unit side body 2 includes a key input unit 11 and a microphone 12 to which a voice uttered by a user of the mobile phone 1 is input on the surface unit 10. The key input unit 11 includes a function setting operation button 13 for operating various functions such as various setting functions, a phone book function, and a mail function, and an input operation button 14 for inputting a telephone number and mail characters. And a determination operation button 15 for performing determination and scrolling in various operations.

  The display unit side body 3 includes a display unit 21 for displaying various types of information on the surface unit 20 and a receiver 22 for outputting the voice of the other party of the call.

  Further, the upper end portion of the operation unit side body 2 and the lower end portion of the display unit side body 3 are connected via a hinge mechanism 4. In addition, the mobile phone 1 relatively rotates the operation unit side body 2 and the display unit side body 3 which are connected via the hinge mechanism 4, so that the operation unit side body 2 and the display unit side body 3 are rotated. The body 3 can be in an open state (open state), or the operation unit side body 2 and the display unit side body 3 can be folded (folded state).

  FIG. 2 is a block diagram showing functions of the mobile phone 1 according to the present embodiment. The mobile phone 1 includes a display unit 21, a CPU 30, a communication control unit 31, a main antenna 32, a voice control unit 33, a microphone 12, a receiver 22, a key input unit 11, a memory 34, and GPS communication. The unit 35 and the GPS antenna 36 are provided.

  The CPU 30 controls the entire mobile phone 1 and performs predetermined control on the display unit 21, the communication control unit 31, the voice control unit 33, the GPS communication unit 35, and the like, for example. In addition, the CPU 30 receives input from the key input unit 11 or the like and executes various processes. Then, the CPU 30 controls the memory 34 to execute reading of various programs and data and writing of data when executing processing.

  In particular, in this embodiment, CPU30 will output the acquired positional information based on the predetermined | prescribed process with communication with a base station, if the positioning request | requirement of a present position is received from a user.

  The display unit 21 performs predetermined image processing according to the control of the CPU 30. Then, the processed image data is stored in the frame memory and output to the screen at a predetermined timing.

  The communication control unit 31 communicates with an external device (base station) in a predetermined use frequency band (for example, a 2 GHz band as a first communication system, an 800 MHz band as a second communication system, or the like). Then, the communication control unit 31 demodulates the signal received from the main antenna 32, supplies the processed signal to the CPU 30, modulates the signal supplied from the CPU 30, and sends the signal from the main antenna 32 to the external device. Send.

  In particular, in the present embodiment, the communication control unit 31 connects to a positioning calculation server from a base station via a network in addition to transmission / reception of signals related to voice calls, mails, etc., and acquires satellite acquisition auxiliary information, positioning results, etc. To get. Note that the positioning method executed by the CPU 30 is different depending on the satellite capture status, and the contents of the transmitted and received data are also different.

  The audio control unit 33 performs predetermined audio processing on the signal supplied from the communication control unit 31 under the control of the CPU 30 and outputs the processed signal to the receiver 22. The receiver 22 outputs the signal supplied from the audio control unit 33 to the outside. This signal may be output from a speaker (not shown) instead of or together with the receiver 22.

  The voice control unit 33 processes a signal input from the microphone 12 according to the control of the CPU 30 and outputs the processed signal to the communication control unit 31. The communication control unit 31 performs a predetermined process on the signal supplied from the audio control unit 33 and outputs the processed signal from the main antenna 32.

  The memory 34 includes, for example, a working memory and is used for arithmetic processing by the CPU 30. In the present embodiment, a program for executing processing to be described later, a threshold value that is referred to when making various determinations, and the like are stored. Note that the memory 34 may also serve as a removable external memory.

  The GPS communication unit 35 demodulates a radio signal of a predetermined frequency band received from the GPS satellite 36 and supplies the processed signal to the CPU 30.

  The communication control unit 31 and the main antenna 32 described above are so-called dual-band types corresponding to the 2 GHz band as the first communication system and the 800 MHz band as the second communication system. The communication control unit and the antenna may be provided for each frequency band. The functions of the GPS communication unit 35 and the GPS antenna 36 may be performed by the communication control unit 31 and the main antenna 32, respectively.

  Here, the types of GPS positioning in the mobile phone 1 will be described. Positioning includes an Assisted method (auxiliary positioning processing) and a Based method (single positioning processing).

  In the Assisted method, the mobile phone 1 receives satellite acquisition assistance information (Acquisition Assistance data) from the positioning calculation server and searches for satellites. The search result is returned to the positioning calculation server, and the position calculation is performed by the positioning calculation server. The mobile phone 1 receives the position calculation result and outputs it as a positioning result.

  Here, when the mobile phone 1 searches for satellites, if four or more satellites can be captured, GPS Fix mode positioning that can be expected to provide the highest accuracy is performed. Then, positioning is performed in the Hybrid Fix mode using the delay time of the radio wave from the base station, the AFLT Fix mode, and the Sector Fix mode using the position information of the base station.

  In addition, since the search for the satellite is terminated at a predetermined time by the timer, the acquisition may fail depending on the accuracy of the satellite acquisition auxiliary information. That is, when communicating with a distant base station, since the error of the satellite capture auxiliary information is large, the capture sensitivity of the satellite is deteriorated, and there is a case where the positioning by the high-accuracy GPS Fix mode cannot be performed.

  By the way, the characteristics of the radio wave used for communication differ depending on the frequency, and the first communication system (2 GHz band), which is a high frequency, is more straight ahead than the second communication system (800 MHz band). That is, in an open area that can be seen far away, a high-frequency base station that is farther away than a low-frequency base station may be captured.

  In addition, infrastructure installation conditions differ for each communication system. For example, in Japan, infrastructure for a 2 GHz band that has been expanded and installed later has a significantly lower base station installation density than an 800 MHz band. Therefore, there is a high possibility that the base station is far away when the first communication system (2 GHz band) is used.

  In the Base system, the mobile phone 1 receives satellite information (Ephemeris data and Almanac data) from the base station. The mobile phone 1 searches for satellites after creating satellite capture auxiliary information based on the received satellite information. Furthermore, the mobile phone 1 performs its own position calculation without transmitting the search result to the positioning calculation server. Therefore, the Based method cannot perform positioning when the mobile phone 1 cannot capture the satellite.

  The mobile phone 1 normally employs the Assisted system that can perform positioning stably even if the satellite capture sensitivity deteriorates and the positioning accuracy decreases. Further, with the Assisted method, the position calculation is performed by the positioning calculation server, so that the processing load on the CPU 30 is small.

  Here, the mobile phone 1 performs communication by giving priority to the first communication system (2 GHz band) that excels in high-speed data communication and the like. However, in the first communication system, as described above, the positioning accuracy in the Assisted method may be reduced. Therefore, the mobile phone 1 performs handoff to communication in the second communication system (800 MHz band) according to the situation, and attempts high-precision positioning using a neighboring base station.

Hereinafter, based on a flowchart, the detail of the process in CPU30 is demonstrated.
FIG. 3 is a flowchart showing the processing of the CPU 30 in response to the first positioning request according to the present embodiment. It is assumed that the mobile phone 1 is communicating with a base station using the first communication system (2 GHz band).

  In step S <b> 11, the CPU 30 performs positioning using the normal Assisted method using the communicating base station.

  In step S12, the CPU 30 performs positioning based on the Base method in order to compare with the positioning result in step S11.

  In step S13, the CPU 30 compares the positioning result in step S11 with the positioning result in step S12, and determines whether or not the difference between them, that is, whether the linear distance between the positioning points is larger than the threshold value 1 (first threshold value). judge. If this determination is YES, it can be determined that the Assisted positioning error in step S11 is large and the distance from the base station has an influence on the positioning error, and the process moves to step S14. On the other hand, if the determination is NO, it can be determined that the error in Assisted positioning is small, and the process proceeds to step S15.

  Here, when the positioning in step S11 or step S12 has failed, the environment for positioning is insufficient in both cases, and the process proceeds to step S14. That is, when Assisted positioning fails, there is a possibility that the satellite acquisition auxiliary information from the base station is incomplete. In addition, when Based positioning fails, there is a possibility that high-accuracy Assisted positioning (GPS Fix mode) cannot be performed because the GPS reception environment is insufficient. Furthermore, when both positionings fail, the GPS reception environment and the communication environment with the base station are insufficient, so the base station that is the communication partner should be changed to improve the environment.

  Note that the threshold value 1 in this process may be set to several tens of meters to several hundreds of meters for the purpose of increasing positioning accuracy, for example. For example, the value may be set to about 2 km for the purpose of avoiding a distant base station.

  In step S14, the CPU 30 performs a handoff to the base station using the second communication system (800 MHz band) that can be expected to be closer to improve the accuracy of Assisted positioning. And CPU30 performs positioning by an Assisted system using the base station of a handoff destination.

  In step S15, the CPU 30 notifies position information based on the positioning result in step S11. And CPU30 continues the positioning by the Assisted system using the base station of a 1st communication system (2 GHz band) (following the process of FIG. 4).

  FIG. 4 is a flowchart showing a continuous positioning process in the CPU 30 according to the present embodiment. It is assumed that the mobile phone 1 is communicating with the base station using the first communication system (2 GHz band) following the processing of FIG.

  In step S21, the CPU 30 acquires the position information of the base station held by the communicating base station. This step only needs to be executed once when the communication partner base station is switched. That is, since the location information of the base station is the same until the handoff occurs, the location information acquisition operation of the base station can be omitted after the second time.

  In step S22, the CPU 30 acquires the previous positioning result. Since the mobile phone 1 is in continuous positioning, it is considered that the mobile phone 1 is not far away from the previous positioning time, so the previous positioning result is acquired as an approximate current position.

  In step S23, the CPU 30 calculates the distance between the position of the base station acquired in step S21 and the approximate current position acquired in step S22, and this distance is greater than the threshold value 2 (second threshold value). It is determined whether or not. If this determination is YES, since the base station is far away, it is determined that the error of the satellite acquisition auxiliary information becomes large, and the process proceeds to step S26. On the other hand, if the determination is NO, since the base station is in the vicinity, it is determined that the error of the satellite acquisition auxiliary information is small, and the process proceeds to step S24.

  Note that the threshold 2 in this process may be set to a value of about several km in consideration of the range that can be covered by the base station, for example. Further, for example, it may be set to a smaller value for the purpose of encouraging use of a closer base station.

  In step S24, the CPU 30 determines that the base station is close and has sufficient positioning accuracy, and performs normal Assisted positioning using the currently communicating base station.

  In step S25, the CPU 30 notifies position information based on the positioning result in step S24. And CPU30 returns to step S22 and continues the positioning by the Assisted system using the base station of a 1st communication system (2 GHz band).

  In step S26, since the error of the satellite acquisition auxiliary information is large and it is difficult to acquire the satellite in a short time, the CPU 30 extends the execution time of the satellite search in order to acquire the satellite more reliably. , Positioning by the Assisted method.

  In step S27, the CPU 30 determines whether or not four or more satellites can be captured in step S26 and the GPS Fix mode is set. If this determination is YES, since the positioning with high accuracy has been achieved by extending the search time of the satellite, the process proceeds to step S30. On the other hand, if the determination is NO, the positioning accuracy may be reduced because the base station is far away, and the process moves to step S28.

  In step S28, the CPU 30 examines the influence of using a distant base station, so that the difference (distance) between the position of the previous positioning result and the position of the current positioning result is the threshold value 3 (third It is determined whether or not the threshold value is larger. If this determination is YES, it is determined that the positioning error has increased due to the remote base station, and the process proceeds to step S29. On the other hand, if the determination is NO, it is determined that the positioning error is small, the communication with the current base station is continued, and the process proceeds to step S30.

  The threshold value 3 in this process may be set to a value of several tens of meters to several hundreds of meters as an allowable error in actual use, for example. In addition, for example, for the purpose of determining that the positioning is normal, the value may be set to about several kilometers.

  In step S29, the CPU 30 performs handoff to the base station using the second communication system (800 MHz band) capable of more stable positioning in order to improve positioning accuracy. And CPU30 performs positioning by an Assisted system using the base station of a handoff destination.

  In step S30, since the positioning result of step S26 is sufficiently reliable, the CPU 30 notifies the position information based on the positioning result. And CPU30 returns to step S22 and continues the positioning by the Assisted system using the base station of a 1st communication system (2 GHz band).

  Next, details of the operation of the mobile phone 1 classified according to each situation will be described. The CPU 30 of the mobile phone 1 executes positioning software in response to receiving a positioning request from a predetermined application being executed, and provides position information to the application.

  FIG. 5 is a sequence diagram when it is determined that there is an influence of the base station in the initial positioning according to the present embodiment.

  First, the positioning software accepts a positioning request from an application, and when the currently communicating base station uses the first communication system (2 GHz band), performs Assisted positioning and Based positioning. Here, in the assisted positioning, the positioning software searches the satellite based on the satellite acquisition auxiliary information from the positioning calculation server, and acquires the position information calculated by the positioning calculation server based on the search result. In the base positioning, the positioning software searches for satellites after generating satellite acquisition auxiliary information based on satellite information from the base station, and calculates a position based on the search result.

  At this time, it is assumed that the difference between the position information of the Assisted positioning and the position information of the Based positioning is larger than the threshold value 1. Then, the positioning software requests the current base station to perform handoff to the base station using the second communication system (800 MHz band). Thus, when handed off to a new base station, the positioning software performs the Assisted positioning again and provides position information to the application.

  FIG. 6 is a sequence diagram when it is determined that there is no influence of the base station in the initial positioning according to the present embodiment.

  First, the positioning software receives a positioning request from the application, as in the case of FIG. 5, and when the currently communicating base station uses the first communication system (2 GHz band), the assisted positioning and the basic positioning are performed. Are executed respectively.

  At this time, it is assumed that the difference between the position information of the assisted positioning and the position information of the Based positioning is equal to or less than the threshold value 1. Then, the positioning software determines that there is no problem in the accuracy of the Assisted positioning, and provides position information obtained by the Assisted positioning to the application. Thereafter, when continuous positioning is performed, the flow becomes one of FIGS.

  FIG. 7 is a sequence diagram when it is determined that the distance from the base station is close and there is no influence of the base station in the continuous positioning according to the present embodiment.

  First, the positioning software receives a positioning request from an application, and when the currently communicating base station uses the first communication system (2 GHz band), the position information of the base station from the message transmitted from the base station. To get. Note that the location information of the base station may be acquired and stored only once when the base station is switched (handed off).

  Next, the positioning software acquires the previous positioning result and calculates the distance to the base station. At this time, it is assumed that the distance from the base station is equal to or less than the threshold value 2. Then, the positioning software determines that there is no problem using the current base station, and provides position information obtained by performing Assisted positioning to the application.

  FIG. 8 is a sequence diagram when it is determined that there is no problem in positioning accuracy and there is no influence of the base station, although satellite acquisition is not sufficient in continuous positioning according to the present embodiment.

  First, the positioning software receives a positioning request from an application as in the case of FIG. 7, and is transmitted from the base station when the base station currently communicating is using the first communication system (2 GHz band). The base station location information is obtained from the message.

  Next, the positioning software acquires the previous positioning result and calculates the distance to the base station. At this time, it is assumed that the distance to the base station is larger than the threshold value 2. Then, the positioning software performs Assisted positioning in which the satellite search time is extended.

  However, if a sufficient number of satellites cannot be acquired even if the search time is extended (the GPS Fix mode is not established), the positioning software determines the difference (distance) between the previously determined position and the currently determined position. Is calculated.

  At this time, it is assumed that the difference between the position measured last time and the position measured this time is equal to or less than the threshold value 3. Then, the positioning software determines that there is no problem in positioning accuracy, and provides the position information obtained by the Assisted positioning to the application.

  FIG. 9 is a sequence diagram when it is determined that there is an influence of the base station in the continuous positioning according to the present embodiment.

  First, as in the case of FIG. 8, the positioning software receives a positioning request from an application, and is transmitted from the base station when the currently communicating base station uses the first communication system (2 GHz band). The base station location information is obtained from the message.

  Next, the positioning software acquires the previous positioning result and calculates the distance to the base station. At this time, it is assumed that the distance to the base station is larger than the threshold value 2. Then, the positioning software performs Assisted positioning in which the satellite search time is extended.

  However, if a sufficient number of satellites cannot be acquired even if the search time is extended (the GPS Fix mode has not been established), the positioning software determines the difference (distance) between the previously determined position and the current position. Is calculated.

  At this time, it is assumed that the difference between the position measured last time and the position measured this time is larger than the threshold value 3. Then, the positioning software requests the current base station to perform handoff to the base station using the second communication system (800 MHz band). Thus, when handed off to a new base station, the positioning software performs the Assisted positioning again and provides position information to the application.

  As described above, according to the present embodiment, it is possible to evaluate the accuracy of positioning of the Assisted method in the first communication system (2 GHz band) that is used preferentially by comparing with the positioning result of the Based method. If it is determined that the accuracy is low, handoff is performed to the second communication system (800 MHz band) where more stable positioning can be expected, so that the accuracy of GPS positioning can be improved.

  Also, when communicating with a distant base station, the satellite search time is extended, so the possibility that the satellite can be captured increases. Therefore, it becomes easy to perform highly accurate positioning by the GPS Fix mode, and the accuracy of GPS positioning can be improved.

  Furthermore, if the GPS Fix mode is not established even if the satellite search time is extended, the accuracy of the current positioning result can be evaluated by comparing with the previous positioning result. If it is determined that the accuracy is low, handoff is performed to the second communication system (800 MHz band) where more stable positioning can be expected, so that the accuracy of GPS positioning can be improved.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 is an external perspective view of a mobile phone according to an embodiment of the present invention. It is a block diagram which shows the function of the mobile telephone which concerns on embodiment of this invention. It is a flowchart which shows the process of the first positioning which concerns on embodiment of this invention. It is a flowchart which shows the process of the continuous positioning which concerns on embodiment of this invention. It is a sequence diagram at the time of determining that there is an influence of a base station in the initial positioning according to the embodiment of the present invention. It is a sequence diagram at the time of determining that there is no influence of a base station in the initial positioning which concerns on embodiment of this invention. In the continuous positioning according to the embodiment of the present invention, it is a sequence diagram when it is determined that the distance from the base station is close and there is no influence of the base station. In the continuous positioning according to the embodiment of the present invention, although satellite acquisition is not sufficient, there is no problem in positioning accuracy, and it is a sequence diagram when it is determined that there is no influence of a base station. FIG. 10 is a sequence diagram when it is determined that there is an influence of a base station in continuous positioning according to the embodiment of the present invention.

Explanation of symbols

1 Mobile phone (mobile terminal)
11 Key Input Unit 12 Microphone 21 Display Unit 22 Receiver 30 CPU (Control Unit)
31 Communication control unit (wireless communication unit)
32 Main antenna 33 Voice control unit 34 Memory 35 GPS communication unit 36 GPS antenna

Claims (5)

A wireless communication unit that registers a position in any of a plurality of communication systems;
Independent positioning processing that receives a GPS signal and identifies the current location by calculation from the GPS signal, and information that is received by the wireless communication unit via the GPS signal and the communication system in use An auxiliary positioning process that identifies the current location based on the control unit, and
When the positioning is performed while the position is registered in the first communication system, the positioning results of both the single positioning process and the auxiliary positioning process have an opening exceeding the first threshold. In this case, the auxiliary positioning process is performed using the second communication system.   The mobile terminal according to claim 1, wherein the first communication system is a communication system used in a base station having a lower density of installation than the second communication system.   The mobile terminal according to claim 1 or 2, wherein the first communication system has a higher frequency band than the second communication system. The wireless communication unit acquires location information of a base station via the communication system in use,
In the auxiliary positioning process, when the distance between the previous positioning result and the position information of the base station exceeds a second threshold when performing the continuous positioning by the auxiliary positioning process, The mobile terminal according to any one of claims 1 to 3, wherein a search time for the satellite is extended.   As a result of extending the search time of the satellite, the control unit captures only 3 or less satellites, and when the difference between the previous positioning result and the current positioning result exceeds a third threshold, The mobile terminal according to claim 4, wherein the auxiliary positioning process is performed using a communication system.

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