JP2009198275A - Mobile communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication terminal for exhibiting a GPS function, even when it moves from the inside to outside of a service area of a radio communication network. <P>SOLUTION: In the mobile communication terminal 1, GPS receiving sections 16 and 17 receive satellite electric wave via a built-in GPS antenna 11G, and generate a GPS signal, based on this satellite electric wave. A connection detection section 18 detects a state, where an external GPS antenna 2 is connected to a connector 15. At this time, a GPS processing section 14A switches the state of the stand-alone positioning mode from off to on, captures the GPS signal, in accordance with the stand-alone positioning mode, and can execute positioning operation based on the capture result. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mobile communication terminal having a GPS (Global Positioning System) function.

  In recent years, GPS functions tend to be implemented in mobile communication terminals such as mobile phones and PDAs (Personal Data Assistance) due to the reduction in size, weight, cost and power consumption of GPS receivers. The GPS receiver receives GPS signals from a plurality of artificial satellites orbiting the earth, captures and tracks the received GPS signals, and navigation message data (satellite orbit information, satellite clocks) from the received GPS signals. Information etc.) and positioning calculation is performed based on the navigation data.

  However, there is a reality that it is difficult for a mobile communication terminal such as a mobile phone to perform high-speed positioning calculation alone. This is because there are many places where it is difficult to obtain sufficiently high reception sensitivity of GPS signals only by using a small GPS antenna built in the mobile communication terminal. Therefore, A-GPS (Assisted GPS) technology is used in which a mobile communication terminal grasps the current position using data supplied from a base station on a communication network, that is, an assistance server. In this A-GPS technology, the mobile communication terminal captures a GPS signal and transmits the capture result to the assist server. The assist server transmits navigation message data to the mobile communication terminal based on the acquisition result received from the mobile communication terminal. And a mobile communication terminal performs a positioning calculation based on the navigation message data received from the assist server (terminal side positioning mode: UE-based mode). Alternatively, the assist server performs a positioning calculation for the current position of the mobile communication terminal based on the acquisition result received from the mobile communication terminal, and transmits the calculation result to the mobile communication terminal (terminal-assisted positioning mode: UE− assisted mode). Such A-GPS technology is disclosed in, for example, Patent Document 1 (Japanese Patent Publication No. 2007-518064) and Patent Document 2 (US Patent Application Publication No. 2006/0276167).

If the external antenna can be detachably connected to the mobile communication terminal, the GPS signal reception sensitivity can be improved and the positioning time can be shortened. Conventional techniques relating to this type of external antenna are disclosed in, for example, Patent Document 3 (Japanese Patent Laid-Open No. 09-229711) and Patent Document 4 (Japanese Patent Laid-Open No. 2001-356159).
Special table 2007-518064 gazette US Patent Application Publication No. 2006/0276167 JP 09-229711 A JP 2001-356159 A

  As described above, a mode in which the mobile communication terminal acquires navigation message data by itself and performs positioning calculation based on the navigation message data is called a stand-alone (or stand-alone positioning mode). For example, with A-GPS, a positioning time of about 5 seconds is sufficient, whereas with a stand-alone, a positioning time of about 40 seconds may be required. In addition, it is difficult to use a stand-alone in a place where the radio wave reception environment is as bad as possible, such as indoors. For this reason, a stand-alone function is not usually mounted on a mobile phone.

  In recent years, the operating frequency of processors such as CPUs and DSPs mounted on mobile communication terminals has increased, and the hardware configuration tends to increase in scale. As a result, there is a problem that the hardware of the mobile communication terminal becomes a noise generation source and degrades the SNR (signal-to-noise ratio) of the GPS signal received by the built-in GPS antenna. The present inventor has found that the SNR of the GPS signal can be deteriorated by about 2 dB due to noise generated by a liquid crystal display (LCD) mounted on the mobile communication terminal, and that the SNR of the GPS signal can be deteriorated by about 5 dB due to noise generated by the CPU. confirmed. Such degradation of the SNR adversely affects GPS performance such as GPS positioning accuracy, positioning time, or positioning rate.

  In order to improve the GPS performance even in such a situation, an external antenna disclosed in Patent Document 2 and Patent Document 3 can be used. However, since the mobile communication terminal cannot receive assist data when the mobile communication terminal moves out of the communication network, the A-GPS function cannot be used.

  The present invention has been made in view of the above, and provides a mobile communication terminal capable of exhibiting GPS performance even when moving from within a range of a wireless communication network.

  ADVANTAGE OF THE INVENTION According to this invention, the mobile communication terminal connected via the radio | wireless communication network with the base station which supplies the assist data for GPS is provided. The mobile communication terminal includes a built-in GPS antenna and a GPS receiver that receives satellite radio waves from a plurality of artificial satellites via the built-in GPS antenna and generates a first GPS signal based on the received satellite radio waves. A GPS processing unit that captures the first GPS signal in accordance with the normal positioning mode and obtains a positioning result using the GPS assist data; and a transmission result obtained by the GPS processing unit is transmitted to the base station and the base station A communication processing unit that receives the GPS assist data returned from the station, a connector that is detachably connected to an external GPS antenna, and a connection detection that detects a state in which the external GPS antenna is connected to the connector And the connection detecting unit detects that the external GPS antenna is connected to the built-in G A switch that electrically disconnects the S antenna and the GPS receiver and electrically connects the external GPS antenna to the GPS receiver, and the GPS receiver is connected to the connector. Satellite radio waves are received from a plurality of artificial satellites via a connected external GPS antenna, a second GPS signal is generated based on the received satellite radio waves, and the GPS processing unit is When the state where the external GPS antenna is connected is detected, the stand-alone positioning mode is switched from off to on, and the stand-alone positioning mode is used when the mobile communication terminal is outside the range of the wireless communication network. To capture the second GPS signal and execute a positioning operation based on the capture result.

  As described above, in the mobile communication terminal according to the present invention, when the connection detection unit detects the connection state of the external GPS antenna, the GPS processing unit switches the stand-alone positioning mode state from OFF to ON according to the detection result. The GPS signal is captured according to the stand-alone positioning mode, and the positioning calculation is executed based on the captured result. Therefore, the user can cause the mobile communication terminal to perform GPS positioning even when the mobile communication terminal moves out of the wireless communication network by simply connecting the external GPS antenna to the connector.

  Hereinafter, various embodiments according to the present invention will be described with reference to the drawings. Note that in all the drawings, components having the same reference numerals have the same configuration, and detailed description thereof is omitted as appropriate so as not to overlap.

  FIG. 1 is a functional block diagram showing a schematic configuration of a mobile communication terminal (GPS receiver) 1 according to an embodiment of the present invention. The mobile communication terminal 1 includes a communication antenna 11A, a first RF circuit 12, a CCPU unit (communication CPU unit) 13 that is a baseband processor, and an ACPU unit (application CPU unit) 14 that is an application processor. . The memory circuit 20 has a storage area in which control information is written, and the CCPU unit 13 writes the control information to the memory circuit 20 and reads the control information from the memory circuit 20. The memory circuit 21 also has a storage area in which control information is written, and the ACPU unit 14 writes the control information to the memory circuit 21 and reads the control information from the memory circuit 21.

  Each hardware configuration of the CCPU unit 13 and the ACPU unit 14 may be a general-purpose configuration, and includes, for example, a CPU (Central Processing Unit), a main memory, a cache memory, a bus circuit, an input / output interface, and a timer circuit. Anything is acceptable. The CCPU unit 13 mainly has a communication control function, and this communication control function can be realized by using an OS (Operating System) or a communication control program corresponding to high real-time characteristics.

  A communication processing unit is configured by the first RF circuit 12 and the CCPU unit 13, and this communication processing unit uses a communication antenna 11A, and a base station, that is, an assist server (not shown) on a wireless communication network (mobile communication network). A function of transmitting and receiving data to and from the terminal. Specifically, when the communication processing unit receives data, the first RF circuit 12 receives a radio signal arriving from the base station via the communication antenna 11A, amplifies the received signal, and adds the frequency to the amplified signal. Convert to generate IF (Intermediate Frequency) signal. The first RF circuit 12 further A / D converts the IF signal into a digital reception signal, and provides this digital reception signal to the CCPU unit 13. On the other hand, when the communication processing unit transmits data to the base station, the first RF circuit 12 D / A converts the digital signal into an analog signal and converts the analog signal into a high-frequency signal. The first RF circuit 12 transmits a high-frequency signal to the wireless communication network using the communication antenna 11A.

  The mobile communication terminal 1 further includes a built-in GPS antenna 11G, a switch 19, a second RF circuit 16, and a GPS module 17. The second RF circuit 16 and the GPS module 17 constitute a GPS receiver. The GPS receiver receives satellite radio waves from a plurality of artificial satellites via the built-in GPS antenna 11G, and based on the received satellite radio waves. And a function of generating a GPS signal (first GPS signal). Specifically, the second RF circuit 16 receives a radio signal of satellite radio waves via the built-in GPS antenna 11G, amplifies the received signal, and converts the frequency of the amplified signal into an IF signal. The second RF circuit 16 further converts the IF signal into a digital reception signal, and provides the digital reception signal to the GPS module 17. The GPS module 17 demodulates the digital reception signal to generate a GPS signal. Then, this GPS signal is transferred to the ACPU unit 14.

  The ACPU unit 14 includes a GPS processing unit (GPS engine) 14A. The GPS processing unit 14A is realized by executing an application program read from a recording medium such as a nonvolatile memory. As schematically shown in FIG. 2, the GPS processing unit 14 </ b> A has two operation modes of an A-GPS positioning mode (normal positioning mode) 141 and a stand-alone positioning mode 142.

  The A-GPS positioning mode 141 is a normal operation mode for obtaining positioning results using an assist server on a wireless communication network. The A-GPS positioning mode 141 is always on. When the mobile communication terminal 1 is in the range of the wireless communication network, according to the A-GPS positioning mode, the mobile communication terminal 1 executes positioning calculation based on the navigation message data received from the assist server (terminal-side positioning mode: UE-based mode), or the positioning calculation execution result is received from the assist server (terminal-assisted positioning mode: UE-assisted mode).

  In the A-GPS positioning mode 141, the GPS processing unit 14A captures and tracks the GPS signal transferred from the GPS module 17, and transfers the captured result to the CCPU unit 13. The CCPU unit 13 controls the first RF circuit 12 to transmit the capture result to the base station. The base station, which is an assist server, generates GPS assist data based on the acquisition result, and returns the assist data to the mobile communication terminal 1. When the GPS processing unit 14A operates in the terminal-side positioning mode (UE-based mode), the base station transmits navigation message data as assist data without executing positioning calculation. On the other hand, when the GPS processing unit 14A operates in the terminal-assisted positioning mode (UE-assisted mode), the base station performs a positioning calculation on the current position of the mobile communication terminal 1, and transmits the calculation result as assist data. . The GPS processing unit 14A acquires the positioning result using the assist data received by the first RF circuit 12 and the CCPU unit 13.

  On the other hand, the stand-alone positioning mode 142 is automatically switched from the off state to the on state when the connector 2C of the external GPS antenna 2 is physically connected to the connector 15. The connector 2C is detachably connected to the connector 15 of the mobile communication terminal 1. Here, the connector 15 may be configured as an I / O connector, an earphone plug, or a dedicated connector.

  When the connector 2C of the external GPS antenna 2 is connected to the connector 15 of the mobile communication terminal 1, the voltage level of the connection conductor 15V connected to the connection detection terminal of the connector 15 changes. The connection detection unit 18 detects a state in which the external GPS antenna 2 is connected to the connector 15 when the voltage level changes and reaches a threshold level, and generates a detection signal Ds representing the state. This detection signal Ds is supplied to the ACPU unit 14. At the same time, the connection detector 18 supplies the switch control signal Sc to the switch 19. In response to the supply of the switching control signal Sc, the switch 19 electrically disconnects the built-in GPS antenna 11G and the second RF circuit 16. As a result, only the external GPS antenna 2 is electrically connected to the second RF circuit 16 via the connector 15.

  At this time, the second RF circuit 16 receives a radio signal of satellite radio waves via the external GPS antenna 2, amplifies the received signal, and converts the frequency of the amplified signal into an IF signal. The second RF circuit 16 further converts the IF signal into a digital reception signal, and provides the digital reception signal to the GPS module 17. The GPS module 17 demodulates the digital reception signal to generate a GPS signal (second GPS signal). Then, this GPS signal is transferred to the ACPU unit 14.

  On the other hand, the GPS processing unit 14A switches the state of the stand-alone positioning mode 142 from off to on according to the detection signal Ds supplied by the connection detection unit 18. The GPS processing unit 14A can capture and track the GPS signal transferred from the GPS module 17 in accordance with the stand-alone positioning mode 142, and execute a positioning calculation based on the captured result. The CCPU unit 13 detects whether the mobile communication terminal 1 is in or out of the wireless communication network based on the radio wave reception level, and gives the detection result to the GPS processing unit 14A. The GPS processing unit 14A prioritizes the A-GPS positioning mode 141 over the stand-alone positioning mode 142 when the external GPS antenna 2 is connected to the connector 15 and the mobile communication terminal 1 is within the wireless communication network. . On the other hand, the GPS processing unit 14A operates only according to the stand-alone positioning mode 142 when the external GPS antenna 2 is connected to the connector 15 and the mobile communication terminal 1 is outside the range of the wireless communication network.

  FIG. 3 is a diagram schematically illustrating an example of the circuit configuration of the external GPS antenna 2, the connector 15, and the connection detection unit 18. The external GPS antenna 2 shown in FIG. 3 has a coaxial cable structure including a core wire 2W that is an antenna wire, a ground conductor (GND conductor) 2G that covers the core wire 2W, and an insulating member that covers and protects the ground conductor 2G. have. The base end portion of the external GPS antenna 2 is a connector 2C composed of a first terminal connected to the core wire 2W and second and third terminals connected to the ground conductor 2G.

  On the other hand, the connector 15 of the mobile communication terminal 1 has three terminals respectively corresponding to the first to third terminals of the connector 2C, and the core wire 2W of the connector 2C is electrically connected to the connection conductor 15W through these terminals. The ground conductor 2G of the connector 2C is electrically connected to the ground conductor 15G and the connection conductor 15V. A reference potential (ground potential GND) is applied to the ground conductor 15G.

  In addition to the voltage monitoring unit 30, the connection detection unit 18 includes an operational amplifier (operational amplifier) 31, a switch control element 32, a constant voltage power supply 33, and a resistance element 34. A power supply voltage is applied to the non-inverting input terminal (+) of the operational amplifier 31 through the resistance element 34, and a threshold voltage supplied from the constant voltage power supply 33 is applied to the inverting input terminal (−) of the operational amplifier 31. Has been. The switch control element 32 can be constituted by, for example, a light emitting diode that generates an optical signal as the switching control signal Sc. On the other hand, the switch 19 can be composed of a photovoltaic element (PVD: Photo-Voltaic Diode) that operates in response to the optical signal Sc and a switching transistor (for example, MOSFET) serving as a contact. The switch control element 32 and the switch 19 may constitute a single photo MOS relay.

  When the connector 2C of the external GPS antenna 2 is not connected to the connector 15 of the mobile communication terminal 1, the power supply voltage Vcc is applied to the non-inverting input terminal of the operational amplifier 31. Further, since the voltage level of the output terminal of the operational amplifier 31 becomes high level (High), the switch control element 32 supplies the switching control signal Sc to the switch 19 and keeps the state of the switch 19 on. Therefore, the built-in GPS antenna 11G is connected to the second RF circuit 16.

  On the other hand, when the connector 2C of the external GPS antenna 2 is connected to the connector 15 of the mobile communication terminal 1, the ground conductor 2G is connected to the connection conductor 15V, so that the non-inverting input terminal of the operational amplifier 31 is the connector 15, 2C. It is electrically connected to the grounding conductor 15G via. As a result, a current flows through the resistance element 34 and the voltage level of the non-inverting input terminal of the operational amplifier 31 is lowered. In accordance with the output voltage of the operational amplifier 31 at this time, the switch control element 32 switches the state of the switch 19 from on to off.

  The voltage monitoring unit 30 monitors the voltage level of the non-inverting input terminal of the operational amplifier 31. When the voltage level of the connection conductor 15V changes and reaches the threshold level, the detection signal Ds having a value corresponding to this state is output. Generate. In accordance with the detection signal Ds, the ACPU unit 14 sets the value of the control information stored in the predetermined storage area of the memory circuit 21 (FIG. 1) to a value corresponding to the OFF state of the stand-alone positioning mode 142 (for example, “0 ]) To a value corresponding to the ON state of the stand-alone positioning mode 142 (for example, “1”). The GPS processing unit 14A switches the state of the stand-alone positioning mode 142 from off to on according to the value of the control information.

  Thereafter, when the connector 2C of the external GPS antenna 2 is disconnected from the connector 15 of the mobile communication terminal 1, the power supply voltage Vcc is applied to the non-inverting input terminal of the operational amplifier 31. In response to this, the switch control element 32 supplies the switching control signal Sc to switch the state of the switch 19 from OFF to ON. Further, the ACPU unit 14 changes the value of the control information stored in the memory circuit 21 (FIG. 1) from a value corresponding to the stand-alone positioning mode 142 on state to a value corresponding to the stand-alone positioning mode 142 off state. rewrite. The GPS processing unit 14A switches the state of the stand-alone positioning mode 142 from on to off according to the value of the control information.

  The effect which the mobile communication terminal 1 of the said embodiment has is as follows. In the mobile communication terminal 1, when the connection detection unit 18 detects the state where the external GPS antenna 2 is connected to the connector 15, the GPS processing unit 14 </ b> A determines whether the stand-alone positioning mode 142 is in accordance with the detection result. Switch state from off to on. Therefore, the user can cause the mobile communication terminal 1 to perform GPS positioning only by connecting the external GPS antenna 2 to the connector 15 even when the mobile communication terminal 1 moves out of the wireless communication network.

  Further, since the external GPS antenna 2 is located outside the casing of the mobile communication terminal 1, noise sources (for example, the CCPU unit 13, the ACPU unit 14, and a display device (not shown)) inside the mobile communication terminal 1 are provided. Less susceptible to noise generated. Therefore, high GPS performance can be exhibited.

  On the other hand, when the external GPS antenna 2 is disconnected from the connector 15, the connection detection unit 18 supplies a switching control signal Sc to the switch 19 to switch the state of the switch 19 from off to on. At the same time, the GPS processing unit 14A switches the state of the stand-alone positioning mode 142 from on to off in accordance with the change in the value of the control information in the memory circuit 21. At this time, when the mobile communication terminal 1 moves from outside the range of the wireless communication network, the GPS processing unit 14A automatically selects the A-GPS positioning mode 141 in preference to the stand-alone positioning mode 142. Since the positioning result is obtained, the user can return the operation mode to the original A-GPS positioning mode 141 without removing the external GPS antenna 2 from the connector 15.

  The mobile communication terminal 1 can be used, for example, as a simplified GPS receiver for car navigation when the user moves by car. Alternatively, the mobile communication terminal 1 can be used in the stand-alone positioning mode when the user is out of the range of the wireless communication network (mobile communication network) while climbing.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable. For example, in the above embodiment, the GPS processing unit 14A is realized by executing an application program, but is not limited to this. The GPS processing unit 14 </ b> A may be realized by hardware having a configuration different from that of the ACPU unit 14. In the above embodiment, the CCPU unit 13 and the ACPU unit 14 are separately configured. However, the present invention is not limited to this, and the CCPU unit 13 and the ACPU unit 14 may be realized using a single CPU. .

  Furthermore, the structure of the external GPS antenna 2 is not limited to the coaxial cable structure described above. The external GPS antenna 2 may be, for example, a patch antenna used as a car navigation GPS antenna.

  The mobile communication terminal 1 includes components as a mobile phone, such as an input device, a voice signal processing unit for calling, a display device (for example, a liquid crystal display or an organic EL display), a nonvolatile memory, and a power supply device. Although not possible, these components are not shown for convenience of explanation.

It is a functional block diagram which shows schematic structure of the mobile communication terminal (GPS receiver) of one Example which concerns on this invention. It is a figure which shows typically the operation mode of a GPS process part (GPS engine). It is a figure which shows roughly an example of the circuit structure of a mobile communication terminal.

Explanation of symbols

1 Mobile communication terminal (GPS receiver)
2 External GPS antenna 2C connector 11A Communication antenna 11G Built-in GPS antenna 12 First RF circuit 13 CCPU unit (communication CPU unit)
14 ACPU unit (application CPU unit)
14A GPS processing unit 141 A-GPS positioning mode 142 Stand-alone positioning mode 15 Connector 16 Second RF circuit 17 GPS module 18 Connection detection unit 19 Switch 20, 21 Memory circuit 30 Voltage monitoring unit 31 Operational amplifier (operational amplifier)
32 switch control element 33 constant voltage power supply 34 resistance element

Claims (6)

A mobile communication terminal connected via a wireless communication network to a base station that supplies GPS assist data,
A built-in GPS antenna;
A GPS receiver that receives satellite radio waves from a plurality of artificial satellites via the built-in GPS antenna and generates a first GPS signal based on the received satellite radio waves;
A GPS processing unit that captures the first GPS signal according to a normal positioning mode and obtains a positioning result using the GPS assist data;
A communication processing unit for transmitting the capture result by the GPS processing unit to the base station and receiving the GPS assist data returned from the base station;
A connector detachably connected to an external GPS antenna;
A connection detection unit for detecting a state in which the external GPS antenna is connected to the connector;
When the connection detection unit detects that the external GPS antenna is connected, the internal GPS antenna and the GPS reception unit are electrically disconnected and the external GPS antenna is received by the GPS. A switch that is electrically connected to the unit;
With
The GPS receiving unit receives satellite radio waves from a plurality of artificial satellites via an external GPS antenna connected to the connector, and generates a second GPS signal based on the received satellite radio waves,
The GPS processing unit switches the stand-alone positioning mode from off to on when the connection detection unit detects the state where the external GPS antenna is connected, and the mobile communication terminal is connected to the wireless communication network. A mobile communication terminal that captures the second GPS signal in accordance with the stand-alone positioning mode and executes a positioning calculation based on the capture result when out of the range.   The mobile communication terminal according to claim 1, wherein the GPS processing unit detects a state in which the external GPS antenna is connected by the connection detection unit, and the mobile communication terminal is within a range of the wireless communication network. A mobile communication terminal that prioritizes the normal positioning mode over the stand-alone positioning mode when in a mobile station.   3. The mobile communication terminal according to claim 1, wherein the connection detection unit monitors a voltage level of a connection detection terminal of the connector, and the external GPS antenna is connected when the voltage level reaches a threshold level. A mobile communication terminal that detects a state of being connected to the connector. The mobile communication terminal according to claim 3, wherein
The connection detection unit
An operational amplifier having a non-inverting input terminal to which a power supply voltage is applied and an inverting input terminal to which a threshold voltage is applied;
A switch control element that generates a control signal according to the output level of the operational amplifier;
Including
The switch is a mobile communication terminal that performs a switching operation according to the control signal.   5. The mobile communication terminal according to claim 4, wherein the switch control element is a light emitting diode that generates an optical signal as the control signal.   The mobile communication terminal according to any one of claims 1 to 5, wherein the wireless communication network is a mobile communication network.

Images