JP4093982B2 - Error correction method for portable communication terminal and its geomagnetic sensor - Google Patents

Description

  The present invention relates to a mobile communication terminal such as a mobile phone provided with a geomagnetic sensor for measuring a geographical orientation, and an error correction method for the geomagnetic sensor.

  Conventionally, there has been a demand for a device that confirms the geographical position of the current location and guides the route to the destination by a map, and a car navigation device is known as a device that satisfies such a demand.

  In general, a car navigation device receives and processes signals (hereinafter referred to as GPS signals) transmitted from a plurality of GPS (global positioning system) satellites to determine the geographical position of the current location, and Map data is read from a database stored in a storage unit (DVD, hard disk, etc.) in the apparatus and displayed on a display. In addition, a vehicle movement trajectory is calculated using a vehicle speed sensor and a gyro sensor, and a map matching process is performed to detect the degree of coincidence between this and the road on the map, thereby correcting the positioning error.

  However, even when not in a car, there is a request to know the position of itself and know the way to the destination, and a mobile phone equipped with a simple navigation function appears to satisfy these requests is doing.

  Initially, mobile phones with a navigation function did not have a device for measuring the direction, so a heading-up display commonly used in car navigation devices (a map with the direction of travel toward the top of the screen) It is difficult to display a map that is easy to understand for the user, such as a rotating display.

Therefore, in recent years, a mobile phone with a navigation function has been proposed in which heading-up display is possible by measuring the direction using a geomagnetic sensor.
JP 2004-28837 A JP 2002-328042 A JP-A-10-197258

  By the way, building rebars and train drive systems generate strong magnetic fields that cause geomagnetic sensor detection errors. When pedestrians use mobile phone navigation functions in town, they are often affected by external magnetic fields. The direction accuracy may be reduced.

  On the other hand, the detection value of the geomagnetic sensor includes a static magnetic field error (offset error) generated by components in the mobile phone. This offset error also changes, for example, when a mobile phone is placed on a magnetic object, so that it is necessary to periodically correct the offset error while using the navigation function.

  However, if this offset error correction process is performed in an environment where a strong external magnetic field is received, an erroneous correction is performed, resulting in a steady error in the geomagnetic detection value, and the accuracy of the orientation is reduced. Such a azimuth accuracy reduction state continues until the next offset error correction, and therefore, inaccurate azimuth information continues to be displayed for a long period of time.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an error correction method for a mobile communication terminal and its geomagnetic sensor that can prevent the correction of orientation in an environment in which a geomagnetic detection error due to an external magnetic field is likely to occur. Is to provide.

  According to a first aspect of the present invention, there is provided a geomagnetic sensor for detecting geomagnetism, position information acquisition means for acquiring information related to the geographical position of the current location, display means, and geographical information based on a detection value of the geomagnetic sensor. Processing for calculating the azimuth, and displaying the calculated azimuth information and information on the geographical position of the current location specified based on the positional information acquired by the positional information acquisition means on the display means; and A mobile communication terminal having control means for performing an offset error correction process for detecting and correcting an offset error of the geomagnetic sensor, and storing information related to an accuracy-decreasing area where the accuracy of the detection value of the geomagnetic sensor is reduced And the control means determines whether or not the current location specified based on the position information is included in the reduced accuracy area registered in the storage means, If Hometown is determined to be included in the purified degree drop area, it prohibits the offset error correction process.

  When the detection value of the geomagnetic sensor becomes a predetermined abnormal state within a predetermined time, the control means includes a point specified based on the position information acquired when the abnormality of the detection value occurs. However, a predetermined range may be registered in the storage means as the area of reduced accuracy.

  The first invention may include wireless communication means, and the control means is image information of a map around the current location specified based on position information acquired by the position information acquisition means. The image information of the map to which a predetermined identification number is assigned is acquired from a predetermined information provider via the wireless communication means and displayed on the display means, and the area with reduced accuracy is stored in the storage means. In the case of registration, the map identification number displayed on the display means when the detected value abnormality occurs and the information on the coordinates on the map relating to the point where the detected value abnormality occurs are stored in the memory. It may be registered in the means.

  When the number of accuracy-decreasing areas registered in the storage unit reaches a predetermined upper limit, the control unit registers the newest accuracy-decreasing area, and is the oldest among the registered accuracy-decreasing area information. Information may be deleted.

  According to a second aspect of the present invention, there is provided a geomagnetic sensor for detecting geomagnetism, position information acquiring means for acquiring information related to the geographical position of the current location, display means, and geographical information based on a detection value of the geomagnetic sensor. Processing for calculating the azimuth, and displaying the calculated azimuth information and information on the geographical position of the current location specified based on the positional information acquired by the positional information acquisition means on the display means; and A mobile communication terminal having a control means for performing an offset error correction process for detecting and correcting an offset error of a geomagnetic sensor, comprising a wireless communication means, the control means being specified based on the position information Obtaining information indicating whether or not the current location is included in an accuracy-decreasing area where the accuracy of the detection value of the geomagnetic sensor is reduced, from a predetermined information provider via the wireless communication means, If the current position is acquired information indicating that contained the purified degree drop area, it prohibits the offset error correction process.

  According to a third aspect of the present invention, there is provided a geomagnetic sensor for detecting geomagnetism, position information acquisition means for acquiring information related to the geographical position of the current location, and a geographical orientation calculated based on a detection value of the geomagnetic sensor. And a display means for displaying the information on the geographical position of the current location specified based on the position information acquired by the position information acquisition means, the error of the geomagnetic sensor is corrected. An error correction method for a geomagnetic sensor, comprising: a first step of registering information relating to an accuracy-decreasing area in which the accuracy of a detection value of the geomagnetic sensor is reduced in the storage unit of the mobile communication terminal; and the position information In the second step of determining whether or not the specified current location is included in the reduced accuracy area registered in the storage means in the first step, and in the second step If the serial current position is determined to be included in the precision drop area, and a third step of prohibiting a process of detecting and correcting an offset error of the geomagnetic sensor.

  According to a fourth aspect of the present invention, there is provided a geomagnetic sensor for detecting geomagnetism, position information acquisition means for acquiring information related to the geographical position of the current location, and a geographical orientation calculated based on a detection value of the geomagnetic sensor. And a display means for displaying the information on the geographical position of the current location specified based on the position information acquired by the position information acquisition means, the error of the geomagnetic sensor is corrected. An error correction method for a geomagnetic sensor, which provides predetermined information as to whether or not the current location specified based on the position information is included in a reduced accuracy area where the accuracy of the detection value of the geomagnetic sensor decreases Information indicating that the current location is included in the reduced accuracy area in the first step acquired from the wireless communication means of the mobile communication terminal from the beginning and the first step. If you obtain, and a second step of prohibiting a process of detecting and correcting an offset error of the geomagnetic sensor.

  According to the present invention, it is possible to prevent azimuth correction from being performed in an environment in which a geomagnetic detection error due to an external magnetic field is likely to occur.

  Hereinafter, an embodiment in which the present invention is applied to a multi-function mobile phone having a navigation function and an imaging function will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration example of a system for acquiring geographical position and map information in the mobile phone 100 according to the embodiment of the present invention.

The mobile phone 100 receives GPS signals transmitted from three or more GPS satellites 200 that go around a known orbit. Then, the received information on the GPS signal is transmitted from the base station 300 to the GPS server device 401 via the communication network, and the current location information is acquired from the GPS server device 401.
In addition, the mobile phone 100 transmits the location information of the current location acquired from the GPS server device 401 from the base station 300 to the navigation server device 402 via the communication network, and the map information around the current location is transmitted from the navigation server device 402. get.

  The GPS server device 401 calculates the geographical position (for example, latitude and longitude) of the mobile phone 100 based on the information of the GPS signal transmitted from the mobile phone 100 via the communication network. Then, the calculated position information is transmitted from the communication network to the mobile phone 100 via the base station 300.

  The navigation server device 402 searches the database for map information around the mobile phone 100 based on the position information sent from the mobile phone 100 via the communication network. Then, the searched map information is transmitted from the communication network to the mobile phone 100 via the base station 300.

2, 3, and 4 are diagrams illustrating an example of the appearance of the mobile phone 100.
2 is a perspective view of the mobile phone 100 in the open state, FIG. 3 is a perspective view from one side of the mobile phone 100 in the closed state, and FIG. 4 is a mobile phone in the closed state. 4 is a perspective view from the other side of the telephone 100. FIG.

As shown in the figure, in the mobile phone 100, a first casing (upper casing) 2 and a second casing (lower casing) 3 are openable and closable (movable) via a movable mechanism section 4. It is connected.
In addition, the movable mechanism part 4 is comprised so that two housings, the 1st housing | casing 2 and the 2nd housing | casing 3, can rotate relatively centering on the predetermined | prescribed rotating shaft.

As shown in FIGS. 2 and 3, the first housing 2 has, for example, an LCD (liquid crystal display) panel or the like on the first surface 2a exposed regardless of the operating state (open state, closed state) of the movable mechanism unit 4. A display panel 21 including an organic EL (electroluminescent) display panel is disposed. A speaker 22 is built in the upper portion of the display panel 21 in FIG.
The display panel 21 is included in a display unit 155 described later. The speaker 22 is included in an audio processing unit 156 described later.

  The second housing 3 is configured by superimposing a substrate mounting housing 31 on which a substrate is mounted and a lid side housing 32 forming a lid of the substrate mounting housing 31.

A numeric keypad button 311a, a cursor button 311b, and an enter button 311c are provided on the outer flat surface 31a of the board mounting housing 31 of the second housing 3, that is, the surface 31a that faces one surface of the first housing 2 in the closed state. The operation key 311 is provided. A microphone 312 is built in the lower part of the operation key 311 in FIG.
The operation key 311 is included in a key input unit 154 described later. The microphone 312 is included in an audio processing unit 156 described later.

As shown in FIG. 4, the outer flat surface 32 b exposed in the lid-side housing 32 of the second housing 3 regardless of the open state and the closed state is closer to the side closer to the connecting portion of the movable mechanism portion 4 than the center portion thereof. The optical system 34a of the camera module 34 is disposed.
In addition, on the outer plane 32a of the lid side housing 32 of the second housing 3, the flash light from the built-in flash lamp is radiated to the outside in parallel with the optical system 34a on the side closer to the coupling portion than the optical system 34a. A light emitting window 321 for emitting white light as a photographing assistance during close-up photography or the like is disposed.
The camera module 34 is included in an imaging unit 157 described later.

  As shown in FIGS. 2 and 3, a camera module tact switch 35 is disposed on one side of the second housing 3, and a connecting portion is provided on the other side of the second housing 3. A memory card slot 33 for inserting a memory card is formed on the near side.

FIG. 5 is a perspective view showing a substrate mounting state in the inside 31 b of the substrate mounting housing 31.
As shown in FIG. 5, the main board 37 is attached to the inside 31 b of the board mounting housing 31 over the entire bottom surface.
A memory card unit 159 to which a removable memory card is mounted is mounted on the main board 37 at a position facing the memory card slot 33.
A geomagnetic sensor 158 is mounted at a position near the center of the main board 37 adjacent to the memory card unit 159.

FIG. 6 is a block diagram illustrating a configuration example of the mobile phone 100 according to the embodiment of the present invention.
A mobile phone 100 illustrated in FIG. 6 includes a wireless communication unit 150, a GPS signal reception unit 151, a storage unit 152, an open / close determination unit 153, a key input unit 154, a display unit 155, and a voice input / output unit 156. An imaging unit 157, a geomagnetic sensor 158, a memory card unit 159, and a control unit 160.
The wireless communication unit 150 is an embodiment of the wireless communication means of the present invention.
The GPS signal receiving unit 151 is an embodiment of the GPS signal receiving means of the present invention.
The GPS signal receiving unit 151 and the wireless communication unit 150 are an embodiment of the position information acquisition unit of the present invention.
The open / close determining unit 153 is an embodiment of the operating state determining means of the present invention.
The display unit 155 is an embodiment of the display means of the present invention.
The geomagnetic sensor 158 is an embodiment of the geomagnetic sensor of the present invention.
The memory card unit 159 is an embodiment of the storage medium mounting means of the present invention.
The control unit 160 is an embodiment of the control means of the present invention.

The wireless communication unit 150 performs processing related to wireless communication with the base station 300. For example, the transmission data output from the control unit 160 is subjected to predetermined modulation processing to be converted into a radio signal and transmitted from the antenna. Also, the radio signal received by the antenna is subjected to a predetermined demodulation process to reproduce the received data and output it to the control unit 160.
The wireless communication unit 150 also performs processing for receiving a positioning reference signal transmitted from the base station 300 as position information acquisition means.

  The GPS signal receiving unit 151 receives a GPS signal transmitted from the GPS satellite 20, performs signal processing such as amplification, noise removal, and modulation, and calculates the geographical position of the mobile phone 100 in the GPS server device 401. Get the information you need.

  The storage unit 152 stores a program executed by the control unit 160, constant data used in processing of the control unit 160, variable data that needs to be temporarily stored, captured image data, and the like.

The open / close determination unit 153 determines whether the rotation state of the first housing 2 and the second housing 3 by the movable mechanism unit 4 is the open state or the closed state described above.
For example, the open / close determination unit 153 includes a detector such as a switch that detects a closed state in which the first housing 2 and the second housing 3 overlap each other. Determine.

  When an input operation such as pressing a key is performed on the operation key 311 or the camera module tact switch 35 described above, the key input unit 154 generates a signal corresponding to this and outputs it to the control unit 160. .

  The display unit 155 displays an image corresponding to the image data generated by the control unit 160 on the display panel 21.

  The sound processing unit 156 converts the input sound into an electric sound signal by the microphone 312, performs signal processing such as amplification, analog-digital conversion, and encoding, and outputs the sound data of the processing result to the control unit 160. Output. In addition, the audio data input from the control unit 160 is subjected to signal processing such as decoding, digital-analog conversion, and amplification to generate an audio signal, which is converted into audio by the speaker 22.

  The imaging unit 157 captures an incident image in the optical system 34 a described above, generates still image data or moving image image data, and outputs the image data to the control unit 160. Further, according to the control of the control unit 160, the flash lamp is turned on at the time of imaging, and is emitted from the light emission window 321.

The geomagnetic sensor 158 detects the geomagnetism used for calculating the azimuth.
For example, as shown in FIG. 5, the geomagnetic sensor 158 detects geomagnetism in three directions orthogonal to each other at a fixed position on the main board 37. That is, the geomagnetism in each axial direction is detected using a predetermined three-axis coordinate system set on the main board 37 as a reference. For the detection of geomagnetism, various methods such as a method using excitation of a coil, a method using the Hall effect, and a method using a magnetoresistive element are used.

  In this embodiment, as an example, the geomagnetic sensor 158 includes an analog-digital converter, which converts a geomagnetic analog signal obtained by the above method into an 8-bit digital signal and outputs it. . That is, the detected values of geomagnetism in three directions are output as integer values from “0” to “255”, respectively.

The control unit 160 includes a computer that executes processing based on a program stored in the storage unit 152, and performs various processes related to the overall operation of the mobile phone 100.
For example, as processing related to the function of the telephone, processing for controlling a calling / incoming sequence of the wireless communication unit 150 according to a key input operation in the key input unit 154, and voice data input / output in the voice processing unit 156 Is transmitted / received by the wireless communication unit 150.
As processing related to the data communication function, the wireless communication unit 150 is operated in response to a key input operation in the key input unit 154, communicates with a predetermined mail server device, and exchanges data such as electronic mail. Do.
As processing related to the imaging function, processing for causing the imaging unit 157 to execute imaging processing of a still image or a moving image in response to a key input operation in the key input unit 154, or image processing such as compression encoding on captured image data Processing is performed to store the data in the storage unit 152. When taking a still image, the flash lamp is turned on at an appropriate timing.

  In addition, the control unit 160 calculates the geographical orientation based on the detection value of the geomagnetic sensor 158 as the processing related to the navigation function, and the GPS server device 401 receives the GPS signal information received by the GPS signal receiving unit 151. , A process for acquiring the current position information, a process for transmitting the position information to the navigation server device 402 and acquiring map information around the current position, a positioning signal from the base station 300, and a calculation result of the direction; A process for determining the current location based on the above, a process for controlling the orientation of the map on the display screen of the display unit 155 (heading-up display process), and the like according to the calculation result of the direction.

  Further, the control unit 160 rotates the display image of the display unit 155 according to the determination result of the open / close determination unit 153 in order to deal with the fact that the orientation of the display panel 21 with respect to the user differs 180 degrees between the open state and the closed state. The processing to apply is performed.

  Here, the operation of the mobile phone 100 having the above-described configuration will be described focusing on the navigation function related to the present invention.

  First, GPS signal reception processing will be described.

  FIG. 7 is a flowchart illustrating an example of GPS signal reception processing in the mobile phone 100.

  The control unit 160 controls the GPS signal receiving unit 151 at a fixed timing such as an interval of 2 seconds, for example, and scans the GPS signal from the satellite (steps ST102 and ST104). If the GPS signal can be received as a result of the scan, the information is stored in the storage unit 152 (ST106). Such GPS signal scanning and information storage are repeated for all receivable satellites (steps ST108, ST104, ST106). After all the satellites have been scanned, the processing of steps ST104 to ST108 is performed again after waiting for the next GPS signal reception timing. The control unit 160 always executes such GPS signal reception processing, for example, during a power-on period.

  Next, the navigation process will be described.

  FIG. 8 is a flowchart illustrating an example of navigation processing in the mobile phone 100.

When the start of the navigation process is selected, for example, by a key input operation or the like in the key input unit 154 (step ST122), the control unit 100 first obtains the information obtained by the GPS reception process from the radio communication unit 150 from the base station. 300, processing to transmit to the GPS server device 401 via the communication network is performed (step ST124).
When the GPS server device 401 receives GPS information from the mobile phone 100, the GPS server device 401 calculates the position (for example, latitude and longitude information) of the current location of the mobile phone 100 based on the received GPS information, and the calculation result is transmitted to the communication network. To the mobile phone 100 via the base station 300.
The cellular phone 100 receives the position information transmitted from the GPS server device 401 and stores it in the storage unit 152 (step ST126).

Next, the control unit 100 accesses the navigation server device 402 from the wireless communication unit 150 via the base station 300 and the communication network (step ST128), and transmits the acquired position information to the navigation server device 402 (step ST130). .
When the navigation server device 402 receives the location information from the mobile phone 100, the navigation server device 402 searches the database for information on the map around the current location of the mobile phone 100 specified by the location information, and retrieves the searched map information from the communication network to the base station. The data is transmitted to the mobile phone 100 via 300.
The cellular phone 100 receives the map information transmitted from the navigation server device 402 and stores it in the storage unit 152 (step ST132).

FIG. 9 is a diagram illustrating an example of map information transmitted from the navigation server device 402.
In this embodiment, as an example, it is assumed that a unique identification number is assigned to each map information. The navigation server device 402 manages map data for each predetermined size (for example, 1 km square) based on this identification number. When transmitting map information to the mobile phone 100, the navigation server apparatus 402 uses this identification number as the map number. Send it attached to the data. In the example of FIG. 9, the map around the current location is the identification number MP0, and the four maps are the identification numbers MP1 to MP4.

  When such map information is acquired, the control unit 160 generates map image data around the current location based on the acquired map information, and displays the map on the display panel 21 of the display unit 155 (step ST134).

  The area of the map displayed on the display panel 21 is an area (for example, 200 m × 300 m) narrower than the 1 km square map acquired from the navigation server device 402 as shown in FIG.

The map display method can be selected, for example, from either north-up display (display where the north on the map is on the screen) or heading-up display (display where the traveling direction on the map is on the screen). It is.
When the north-up display is selected by the key operation of the key input unit 154, the control unit 160 fixes the north direction of the map to the upper direction of the display screen and displays it on the display unit 155.

  On the other hand, when the heading-up display is selected by the key operation of the key input unit 154, the control unit 160 performs a process of controlling the orientation of the map on the display screen according to the direction obtained by the direction calculation process described later. . For example, when the traveling direction is a direction A (see FIG. 2) from one end where the microphone 312 of the second housing 3 is disposed to the other end having the connecting portion, the direction of the traveling direction is displayed. The direction of the map on the display screen is controlled so as to go upward.

Note that “above the display screen” described here is a view from the viewpoint of a user who holds the second housing 3 and uses the mobile phone 100, and indicates whether the housing is open or closed. When it is changed, “above the display screen” changes accordingly. That is, when the housing is open, the speaker 22 side of the first housing 2 is above the display screen, and when the housing is open, the connecting portion side of the first housing 2 is above the display screen. .
As will be described later, the control unit 160 performs a process of rotating the image on the display screen in accordance with the open / closed state of the casing, and displays the image in an appropriate direction for the user.

  When the display of the map is started as described above, the control unit 160 repeats the processes after step ST138 described below until the end of the navigation process is selected by the key operation of the key input unit 154 (step ST136). ).

  First, the control unit 160 causes the wireless communication unit 150 to receive positioning reference signals transmitted from a plurality of (for example, three or more) base stations 300 around the mobile phone 100, and based on the received signals, the position of the current location Is calculated (step ST138). Then, the presence / absence of movement of the mobile phone 100 is determined from the calculation result of the current location (step ST140). If it is determined that the mobile phone 100 is not moving, the calculation of the current location based on the reference signal from the base station 300 is continued. Perform (ST138).

If it is determined in step ST140 that the mobile phone 100 has moved, the control unit 160 determines whether or not the destination location is in the area of the edge of the currently acquired map (step ST142). For example, when a part of the map to be displayed on the display unit 155 is not included in the currently acquired map and is included in a map adjacent thereto, the current location is in the area at the end of the map. judge.
If it is determined that the current location is in the end region, the control unit 160 requests the navigation server device 146 for a map adjacent to the end region (step ST146). For example, the navigation server device 146 is transmitted to the navigation server device 146 with the identification number of the currently acquired map and the information indicating which of the east, west, north, and north directions is adjacent to the map.
The navigation server device 146 detects a map corresponding to these pieces of information sent from the mobile phone 100 from the database, and transmits the map to the mobile phone 100.
The cellular phone 100 receives the map information transmitted from the navigation server device 402, stores it in the storage unit 152 (step ST132), and causes the display unit 155 to display a map corresponding to the map information (step ST134). Thereafter, the processes after step ST138 are repeated.
Also, when it is determined that the current location is not in the end region, the control unit 160 performs a process of moving the map display region so that the current location of the mobile phone 100 becomes the center of the map, for example, according to the calculation result of the current location. Thereafter, the processing after step ST138 is repeated.

  Next, display image rotation processing according to the open / closed state of the housing will be described.

  FIG. 10 is a flowchart illustrating an example of display image rotation processing in the mobile phone 100.

Control unit 160 constantly monitors the open / closed state determined by open / close determining unit 153 while the power is on (step ST162). When the open / close determination unit 153 determines that it is not in the closed state (that is, in the open state), an image is displayed on the display panel 21 in a direction in which the speaker 22 side of the first housing 2 is above the image (step ST166). ).
If the display in the open state is a normal display, when the open / close determining unit 153 determines the closed state, the control unit 160 rotates the image in the normal display by 180 degrees and displays the image on the display panel 21 (step ST164). That is, an image is displayed on the display panel 21 in a direction in which the connecting portion side in the first housing 2 is above the image.
By such display image rotation processing, an image can be displayed on the display unit 155 in a direction that is always easy for the user to see regardless of whether the housing is open or closed.

Next, the azimuth calculation processing will be described.
Here, first, an outline of the direction calculation method will be described with reference to FIG. 11, and then several examples of the direction calculation processing in the control unit 160 will be described with reference to FIGS. 12 to 19.

FIG. 11 is a diagram for explaining a method of calculating the azimuth angle.
In FIG. 11, a rectangular coordinate system having coordinate axes Hx, Hy, Hz is a reference coordinate system set on the ground plane. That is, the coordinate axes Hx and Hy are coordinate axes parallel to the ground plane, and each face a predetermined direction. The coordinate axis Hz is a coordinate axis that faces in a direction perpendicular to the ground plane.
The azimuth angle θ is an angle formed by an image Zxy obtained by orthogonally projecting a vector in the reference direction (for example, direction A in FIG. 2) of the geomagnetism detection set on the main substrate 37 of the second housing 3 and the coordinate axis Hx. It is. The inclination angle φ is an angle formed by the image Zxy and a vector in the reference direction A. Further, the twist angle η is an angle obtained by rotating the mobile phone 100 around the rotation axis about the vector in the reference direction A.
When the azimuth angle θ, the inclination angle φ, and the twist angle η are all zero, the geomagnetic detection coordinate system set on the main board 37 of the second housing 3 has coordinate axes Hx, Hy, and Hz shown in FIG. Match the coordinate system.

  Here, if the detected value of geomagnetism corresponding to the coordinate axis Hx is α, the detected value of geomagnetism corresponding to the coordinate axis Hy is β, and the detected value of geomagnetism corresponding to the coordinate axis Hz is γ, the tangent of the azimuth angle θ shown in FIG. tan θ is expressed by the following equation.

(Equation 1)
tan θ = β / (γ · sin φ−α · cos φ) (1)

However, in the formula (1), the twist angle η is zero.
The control unit 160 calculates an azimuth angle according to the detected values of the three directions of geomagnetism obtained from the geomagnetic sensor 158 using a relationship as shown in, for example, the equation (1).

The control unit 160 also takes into account the inclination angle of the display panel 21 with respect to the ground plane when calculating the above-described azimuth.
A general user can view an image on the display panel 21 with an easy posture when the display panel 21 is tilted at an angle of about 45 degrees, for example. Therefore, the control unit 160 calculates the azimuth by Expression (1) using the inclination angle φ when the inclination angle of the display panel 21 with respect to the ground plane is 45 degrees, for example.

In addition, when the inclination angle of the geomagnetic sensor 158 with respect to the ground plane is different between the open state and the closed state, the control unit 160 may calculate the azimuth angle of each state in consideration of the difference in the inclination angle.
For example, the first housing 2 and the second housing 3 overlap each other substantially in parallel in the closed state, whereas the first housing 2 and the second housing 3 are relatively inclined in the open state (for example, “ It is assumed that the two housings are connected so as to incline in the shape of "". In this case, if the user tries to keep the direction of the line of sight with respect to the display panel 21 constant in both operation styles, the inclination of the second housing 3 with respect to the ground plane differs between the open state and the closed state. That the inclination of the second housing 3 is different means that the inclination of the reference direction A with respect to the ground plane is different in the open and closed states. Therefore, the control unit 160 calculates the azimuth using the predetermined inclination angle φ according to the determination result of the open / close determination unit 153. This tilt angle φ is an angle set in advance so that the tilt angle of the display panel 21 with respect to the ground plane is constant at, for example, 45 degrees in both the open state and the closed state.

  The information on the tilt angle is stored in advance in the storage unit 152 as a data table, for example. When the azimuth is detected, the control unit 160 reads the tilt angle information associated with the determination result of the open / close determination unit 153 from the data table, and calculates the azimuth using the tilt angle information.

  FIG. 12 is a flowchart illustrating a first example of orientation calculation processing in the mobile phone 100.

  When the start of navigation processing is selected by a key input operation or the like at key input unit 154 (step ST202), control unit 160 checks whether a predetermined event has occurred (step ST204).

Here, the predetermined event refers to a geomagnetic sensor 158 in a circuit or processing system in the mobile phone 100 when information on the direction (a heading-up display map or a compass indicating the direction) is displayed on the display unit 155. This is an event that generates a magnetic field that causes a change in the detected value.
This predetermined event includes, for example, an event that causes the wireless communication unit 150 to operate when a map is acquired from the navigation server device 402 in step ST146 of FIG. 8 or when an incoming call process or mail reception process is performed.
In addition, an event for changing the display brightness in the display unit 155 according to a key input operation, a change in azimuth information, a map display update, an event for operating the audio processing unit 156 and outputting sound from a speaker, etc. May be included.
In the case where the display unit 155 includes an LCD panel, for example, an event for turning on / off a light source as an LCD backlight or changing the light emission intensity of the light source may be included.

  When the occurrence of such a predetermined event is detected, the control unit 160 reads correction data for the geomagnetic detection value prepared in advance corresponding to the detected event from the storage unit 152, and the correction data currently being used. To change.

FIG. 13 is a diagram illustrating an example of correction data.
In the example of FIG. 13, the correction data is constituted by three correction values corresponding to the detected values of the geomagnetic sensor 158 in the three directions (X axis, Y axis, Z axis). For example, when a communication process for operating the wireless communication unit 150 is executed, the control unit 160 sets “−1”, “0”, “−1” corresponding to the geomagnetic detection values of the X axis, the Y axis, and the Z axis. Are read from the storage unit 152.
The storage unit 152 stores such correction data in association with a plurality of events, for example. Each correction value of the correction data is determined by, for example, measuring in advance the amount of change in the geomagnetic detection value when each event has occurred and when it has not occurred.

Control unit 160 corrects the detection value of geomagnetic sensor 158 based on the correction data read from storage unit 152 (step ST208). That is, the correction values corresponding to the correction data are added to the detected values in the three directions of the geomagnetic sensor. Then, using the corrected geomagnetic detection value, the azimuth is calculated by the above-described calculation method (step ST210).
Control unit 160 repeats the processes of steps ST204 to ST210 described above while the navigation process is being executed (step ST212).

Note that when the occurrence of a plurality of events is detected in step ST204, the control unit 160 adds the correction values of the correction data corresponding to the detected events to the geomagnetic detection values in the three directions, respectively.
For example, in the example of FIG. 13, when both the communication process and the audio output process occur, the X-axis correction value is “−1” + “− 1” = “− 2”, and the Y-axis correction value is “0” + “0” = “0”, and the Z-axis correction value is “−1” + “0” = “− 1”.

In addition, when the end of a certain event is detected in step ST204, the control unit 160 subtracts the correction value of the correction data corresponding to the ended event from the current value.
For example, when the communication processing shown in FIG. 13 is completed when the current X-axis, Y-axis, and Z-axis correction values are “−2”, “−1”, and “1”, the X-axis correction value is “ -2 '-'- 1' = '-1', Y-axis correction value is '-1'-'0' = '-1', Z-axis correction value is '1'-'- 1 '=' Changed to 2 '.

As described above, according to the first example of the azimuth calculation process shown in FIG. 12, the occurrence of a predetermined event that fluctuates the magnetic field inside the mobile phone 100 when the azimuth information is displayed on the display unit 155. (Including the end of the event) is monitored by the control unit 160, and the direction information is corrected when the occurrence of the predetermined event is detected.
Therefore, even if the detection value of the geomagnetic sensor 158 fluctuates due to the occurrence of an event and the accuracy of the orientation information displayed on the display unit 155 decreases, by detecting the occurrence of the event and correcting the orientation information, The accuracy of the direction information can be recovered.
Further, since the direction information is corrected using the correction data determined in advance for each event and stored in the storage unit 152, the direction information can be accurately corrected for each event that occurs.

Next, a second example of the azimuth calculation process will be described.
FIG. 14 is a flowchart illustrating a second example of the direction calculation processing in the mobile phone 100.

  The difference between the first example (FIG. 12) and the second example (FIG. 14) is that the display unit 155 performs an operation for correcting the direction information after detecting the occurrence of a predetermined event. The display unit 155 displays that the accuracy of the direction information displayed on the display unit 155 is low until the calculation result direction information is displayed on the display unit 155.

That is, when detecting the occurrence of a predetermined event in step ST204, control unit 160 causes display unit 155 to display that the accuracy of the orientation information displayed on display unit 155 is low (step ST214).
For example, when an image of a compass representing an azimuth is displayed, it may be indicated that the accuracy of the azimuth information is low by displaying a movement that causes the compass to swing left and right. Further, the shape, color and size of the compass image may be changed, or another image indicating that the orientation accuracy is low may be displayed.

The control unit 160 displays information indicating such a decrease in azimuth accuracy while changing the correction value (step ST206), correcting the geomagnetic detection value (step ST208), and calculating the azimuth (step ST210). Displayed on the unit 155. Then, when the corrected direction information is displayed on the display unit 155, the display unit 155 displays that the accuracy of the direction has been recovered (step ST216).
For example, in the case where a decrease in azimuth accuracy is displayed by a movement of shaking the compass image to the left and right, it may be indicated that the azimuth accuracy has been recovered by stopping the left and right shake. In the case where the deterioration of the azimuth accuracy is displayed by changing the shape, color, and size of the compass image, the accuracy recovery may be expressed by returning this to the original state. Alternatively, another image indicating that the accuracy of the direction information has been recovered may be displayed.

  As described above, according to the second example of the azimuth calculation process shown in FIG. 14, when the correction value of the geomagnetic detection value is changed due to the occurrence of a predetermined event (including the end of the event), a new correction is performed. Until the azimuth is recalculated based on the value and the result is displayed on the display unit 155, the user can be notified that the accuracy of the azimuth information being displayed is low. As a result, the user can correctly grasp whether or not the accuracy of the displayed orientation information is low.

Next, a third example of the azimuth calculation process will be described.
FIG. 15 is a flowchart illustrating a third example of the direction calculation processing in the mobile phone 100.

  In the azimuth calculation processes of the first and second examples described above, the change in the geomagnetic detection value caused by the occurrence of the event is corrected. In the third example described below, the geomagnetism corresponding to the open / closed state of the casing is used. Correct the change in the detected value.

Unlike the dynamic magnetic field generated for each event as described above, the mobile phone 100 includes components that generate a static magnetic field such as a magnet used for the speaker 22. Such a static magnetic field causes a steady error (offset error) of the detected geomagnetic value, and is corrected by an offset error correction process described later. However, when the open / closed state of the housing is changed, the positional relationship of these static magnetic field generation sources with respect to the geomagnetic sensor 158 changes, and the offset error also changes accordingly.
Therefore, in the azimuth calculation process of the third example, in order to reduce the decrease in accuracy of the azimuth calculation value due to such a change in offset error, the offset error correction value obtained by the offset error correction process is set to the open state and the closed state. Keep separate for each. When a change occurs in the open / closed state of the housing, the correction value used for correcting the offset error is changed accordingly.

  When the start of navigation processing is selected by a key input operation or the like in key input unit 154 (step ST302), control unit 160 examines the determination result of open / close determination unit 153 (step ST304). When the open / close determination unit 153 determines that the housing is in the open state, the control unit 160 reads, for example, the open state offset error correction data held in a register (not shown) in the control unit 160 (step). (ST306) Based on this, the detection value of the geomagnetic sensor 158 is corrected (step ST310). When the open / close determination unit 153 determines that the housing is in the closed state, the control unit 160 reads out the offset error correction data in the closed state held in a register (not shown) in the control unit 160 ( Based on this, the detection value of the geomagnetic sensor 158 is corrected (step ST310).

  For example, as shown in FIG. 13, the offset error correction data is composed of three correction values corresponding to the geomagnetic detection values in three directions. This correction value is frequently obtained by an offset error correction process, which will be described later, at the start or during the execution of the navigation process, and written in a predetermined register of the control unit 160 provided for each of the open and closed states. It is. The offset error correction data stored in the register is rewritten whenever an offset error correction process is executed and a new correction value is acquired.

  When the detection value of the geomagnetic sensor 158 is corrected, the control unit 160 calculates the azimuth using the corrected geomagnetic detection value (step ST312).

Next, control unit 160 obtains the determination result of open / close determination unit 153 again, and checks whether there is a change in the open / close state (step ST314).
When the change from the closed state to the open state is detected, the control unit 160 returns to step ST306, reads the offset error correction data in the open state, and uses this to repeat the correction of the geomagnetic detection value and the calculation of the azimuth ( Steps ST310 and ST312).
When the change from the open state to the closed state is detected, the control unit 160 returns to step ST308, reads the offset error correction data in the closed state, and uses this to repeat the correction of the geomagnetic detection value and the calculation of the azimuth ( Steps ST310 and ST312).
If there is no change in the open / close state, the control unit 160 confirms whether or not the end of the navigation process is selected (step ST316), and if the navigation process is continued, the offset error correction data currently in use is used. The correction of the geomagnetic detection value and the calculation of the azimuth are repeated (steps ST310 and ST312).

  When the end of the navigation process is selected, control unit 160 stores the open state and closed state offset error correction data held in the register in storage unit 152 (step ST318). As a result, the next time navigation processing is performed, it is possible to quickly calculate the azimuth using the offset error correction data stored in the storage unit 152.

As described above, according to the third example of the azimuth calculation process shown in FIG. 15, the change in the determination result in the open / close determination unit 153 is monitored when the azimuth information is displayed on the display unit 155. Is detected, the direction information displayed on the display unit 155 is corrected according to the changed state (open state or closed state). That is, when the change is detected, a predetermined correction corresponding to the state after the change is performed on the detection value of the geomagnetic sensor 158, and the azimuth is calculated based on the corrected geomagnetic detection value.
Therefore, in the mobile phone 100 having a structure that allows the display unit 155 to display the orientation information in both the open state and the closed state, the detection value of the geomagnetic sensor 158 varies with the change in the open / close state, Even when the accuracy of the azimuth information decreases, the accuracy of the azimuth information can be recovered by detecting the change in the determination result in the open / close determination unit 153 and correcting the azimuth information.
Further, offset error correction data in each of the open state and the closed state is separately held in a predetermined register of the control unit 160, and correction of azimuth information using appropriate offset error correction data according to the open / close state Therefore, it is possible to correct the direction information with high accuracy in each state.

  In the detection of the change in the open / closed state in step ST314, after detecting the change in the open / closed state based on the determination result of the open / close determining unit 153, the open state or the closed state after this change lasts for a predetermined period of time. It may be finally determined that the change from the closed state to the closed state or from the closed state to the open state has occurred. Thereby, it is possible to prevent the offset error correction data from being erroneously changed when the movable mechanism unit 4 moves unintentionally and a change in the open / close state is detected instantaneously.

Next, a fourth example of the azimuth calculation process will be described.
FIG. 16 is a flowchart illustrating a fourth example of the direction calculation processing in the mobile phone 100.

  The difference between the third example (FIG. 15) and the fourth example (FIG. 16) is that the opening / closing determination unit 153 detects a change in the opening / closing state, recalculates the direction, and calculates the recalculated direction. Until the information is displayed on the display unit 155, the display unit 155 displays that the accuracy of the orientation information displayed on the display unit 155 is low.

That is, the control unit 160 detects a change in the open / closed state in step ST314, and in response to this, reads the offset error correction data corresponding to the changed state in step ST306 or ST308, and then displays the data on the display unit 155. The display unit 155 displays that the accuracy of the orientation information is low (step ST320).
For example, as in step ST214 of FIG. 14 described above, the control unit 160 shakes the compass image indicating the azimuth to the left and right, changes the shape, color, size, and the like of the compass, and indicates a decrease in azimuth accuracy. Information on a decrease in azimuth accuracy is displayed on the display unit 155 by a method such as displaying another image.

The control unit 160 causes the display unit 155 to display information indicating such a decrease in azimuth accuracy while performing correction of the geomagnetic detection value (step ST310) and calculation of the azimuth (step ST312). Then, when the corrected direction information is displayed on the display unit 155, the display unit 155 displays that the accuracy of the direction has been recovered (step ST322).
For example, in the case where a decrease in azimuth accuracy is displayed by moving the compass image to the left and right, the left and right shake may be stopped. In the case where the deterioration of the orientation accuracy is displayed by changing the shape, color, and size of the compass image, it may be returned to the original state. Alternatively, another image indicating that the accuracy of the direction information has been recovered may be displayed.

  As described above, according to the fourth example of the azimuth calculation process shown in FIG. 16, when the correction value of the geomagnetism detection value is changed due to the change in the open / close state of the casing, the azimuth is restored by the new correction value. It is possible to notify the user that the accuracy of the azimuth information being displayed is low until the calculation and the result are displayed on the display unit 155. As a result, the user can correctly grasp whether or not the accuracy of the displayed orientation information is low.

Next, a fifth example of the azimuth calculation process will be described.
FIG. 17 is a flowchart illustrating a fifth example of the azimuth calculation processing in mobile phone 100.

  In the azimuth calculation processes of the third and fourth examples described above, the change in the geomagnetic detection value caused by the change in the open / close state of the casing is corrected. In the fifth example described below, the memory card in the memory card unit 159 is corrected. The change of the geomagnetic detection value according to the presence or absence of wearing is corrected.

If a memory card uses a component that is easily magnetized, such as a lead frame of a semiconductor integrated device, an offset error of the geomagnetic sensor 158 between when the memory card is mounted and when it is not mounted is affected by this magnetism. May change.
FIG. 18 is a diagram illustrating an example of a temporal change in the geomagnetic sensor detection values (X axis, Y axis, Z axis) depending on whether or not a memory card is attached. In the example of FIG. 18, the detected values of the geomagnetic sensors on the X axis, the Y axis, and the Z axis change by “−7”, “−8”, and “−1”, respectively.
In the azimuth calculation process of the fifth example, in order to reduce the azimuth error due to the fluctuation of the detected value of the geomagnetic sensor, the offset error correction value obtained by the offset error correction process is set when the memory card is mounted and when the memory card is not mounted. Keep separate for each. When a change occurs in the mounting state of the memory card in the housing, the correction value used for correcting the offset error is changed accordingly.

  When the start of navigation processing is selected by a key input operation or the like in key input unit 154 (step ST402), control unit 160 checks the memory card mounting state in memory card unit 159 (step ST404). When it is determined that a memory card is inserted based on a signal from the memory card unit 159, the control unit 160 uses, for example, the offset error correction data when the memory card is held held in a register (not shown) in the control unit 160. Reading (step ST406), and based on this, the detection value of the geomagnetic sensor 158 is corrected (step ST410). In addition, when it is determined that a memory card is inserted based on a signal from the memory card unit 159, the control unit 160 stores offset error correction data when the memory card is not installed, which is held in a register (not shown) in the control unit 160. (Step ST408), and based on this, the detection value of the geomagnetic sensor 158 is corrected (step ST410).

  For example, as shown in FIG. 13, the offset error correction data when the memory card is attached and not attached is composed of three correction values corresponding to the geomagnetic detection values in three directions. This correction value is obtained frequently by an offset error correction process, which will be described later, at the start or during the execution of the navigation process, and is a predetermined value in the control unit 160 provided for each of when the memory card is mounted and when it is not mounted. Written to the register. The offset error correction data stored in the register is rewritten whenever an offset error correction process is executed and a new correction value is acquired.

  When the detection value of the geomagnetic sensor 158 is corrected, the control unit 160 calculates the azimuth using the corrected geomagnetic detection value (step ST412).

Next, control unit 160 confirms the memory card mounting state in memory card unit 159 again, and checks whether there is a change in the mounting state (step ST414).
When detecting a change from a state in which no memory card is installed in the memory card unit 159 to a state in which a memory card is installed in the memory card unit 159, the control unit 160 returns to step ST406 and performs an offset when the memory card is installed. The error correction data is read out, and using this, the correction of the geomagnetic detection value and the calculation of the direction are repeated (steps ST410 and ST412).
When detecting a change from the state in which the memory card is installed in the memory card unit 159 to the state in which the memory card unit 159 is not installed in the memory card unit 159, the control unit 160 returns to step ST408 and returns to the state when the memory card is not installed. The offset error correction data is read, and the correction of the geomagnetic detection value and the calculation of the direction are repeated using this data (steps ST410 and ST412).
If there is no change in the memory card mounting state, the control unit 160 checks whether the end of the navigation process is selected (step ST416), and if the navigation process continues, the offset error correction data currently in use. Is used to repeat the correction of the geomagnetic detection value and the calculation of the direction (steps ST410 and ST412).

  When the end of the navigation process is selected, the control unit 160 stores the offset error correction data stored in the register when the memory card is installed and when the memory card is not installed in the storage unit 152 (step ST418). As a result, the next time navigation processing is performed, it is possible to quickly calculate the azimuth using the offset error correction data stored in the storage unit 152.

As described above, according to the fifth example of the azimuth calculation process shown in FIG. 17, the change in the memory card mounting state in the memory card unit 159 is monitored when the azimuth information is displayed on the display unit 155. When the change is detected, the orientation information displayed on the display unit 155 is corrected according to the state after the change (mounted or not mounted). That is, when a change is detected in the mounting state of the memory card, a predetermined correction corresponding to the state after the change is performed on the detection value of the geomagnetic sensor 158, and the direction is determined based on the detection value of the geomagnetism after the correction. Calculated.
Therefore, even if the detection value of the geomagnetic sensor 158 fluctuates due to a change in the mounting state of the memory card and the accuracy of the orientation information displayed on the display unit 155 decreases, the change in the mounting state of the memory card in the memory card unit 159 The accuracy of the azimuth information can be recovered by detecting the azimuth and correcting the azimuth information.
Further, offset error correction data in each of the attached state and the unattached state is separately held in a predetermined register of the control unit 160, and the direction is determined using appropriate offset error correction data corresponding to the attached state of the memory card. Therefore, the direction information can be accurately corrected in each state.

Next, a sixth example of the azimuth calculation process will be described.
FIG. 19 is a flowchart illustrating a sixth example of orientation calculation processing in the mobile phone 100.

  The difference between the sixth example (FIG. 19) and the fifth example (FIG. 17) described above is that the orientation is recalculated after detecting a change in the memory card mounting state, and the recalculated orientation information is obtained. Until the display unit 155 displays the information, the display unit 155 displays that the accuracy of the orientation information displayed on the display unit 155 is low.

That is, the control unit 160 detects a change in the memory card mounting state in step ST414, and in response to this, reads the offset error correction data corresponding to the changed state in step ST406 or ST408, and then displays it on the display unit 155. The fact that the accuracy of the displayed orientation information is low is displayed on display unit 155 (step ST420).
For example, as in step ST214 of FIG. 14 described above, the control unit 160 shakes the compass image indicating the azimuth to the left and right, changes the shape, color, size, and the like of the compass, and indicates a decrease in azimuth accuracy. Information on a decrease in azimuth accuracy is displayed on the display unit 155 by a method such as displaying another image.

The control unit 160 causes the display unit 155 to display information indicating such a decrease in azimuth accuracy while performing correction of the geomagnetic detection value (step ST410) and calculation of the azimuth (step ST412). Then, when the corrected azimuth information is displayed on the display unit 155, the display unit 155 displays that the accuracy of the azimuth has been recovered (step ST422).
For example, in the case where a decrease in azimuth accuracy is displayed by moving the compass image to the left and right, the left and right shake may be stopped. In the case where the deterioration of the orientation accuracy is displayed by changing the shape, color, and size of the compass image, it may be returned to the original state. Alternatively, another image indicating that the accuracy of the direction information has been recovered may be displayed.

  As described above, according to the sixth example of the azimuth calculation process shown in FIG. 19, when the correction value of the geomagnetism detection value is changed due to the change in the mounting state of the memory card, the azimuth is restored by the new correction value. It is possible to notify the user that the accuracy of the azimuth information being displayed is low until the calculation and the result are displayed on the display unit 155. As a result, the user can correctly grasp whether or not the accuracy of the displayed orientation information is low.

  Next, offset error correction processing will be described.

The offset error correction process is a process for correcting an error in a steady geomagnetic detection value generated by a magnetic field generation source inside the mobile phone 100.
The static magnetic field generated inside the mobile phone 100 brings a steady error to the detection value of the geomagnetic sensor 158 regardless of the direction in which the mobile phone 100 is directed. On the other hand, the detected value of the geomagnetism itself changes according to the direction in which the mobile phone 100 is directed. Therefore, for example, by detecting the geomagnetism while rotating the mobile phone 100 and obtaining the locus of the geomagnetic vector according to the rotation of the mobile phone 100, the offset error included in the detection value of the geomagnetic sensor 158 is easily calculated. I can.

For example, when starting the navigation process, the control unit 160 causes the display unit 155 to display an instruction that prompts the user to rotate the mobile phone 100. When the user rotates the mobile phone 100 according to this instruction, the control unit 160 acquires a plurality of detection values of the geomagnetic sensor 158 during the rotation. Then, an offset error is calculated from the vector locus of the acquired geomagnetic detection value, and is subtracted from the detection value of the geomagnetic sensor 158. Thereby, the geomagnetic detection value in which the offset error is corrected is obtained.
The control unit 160 stores the offset error calculated by the offset error correction process as described above in a predetermined register of the control unit 160 as offset error correction data.

  In addition, the control unit 160 performs the above-described offset error correction process, for example, at regular intervals while the navigation process is being performed.

  Further, as will be described below, the control unit 160 performs an offset error correction process to correct the geomagnetic detection value even when the detection value of the geomagnetic sensor 158 enters a predetermined abnormal state such as an overflow.

  FIG. 20 is a flowchart illustrating a first example of offset error correction processing when an abnormal state occurs in the geomagnetic detection value.

When the start of the navigation process is selected by a key input operation or the like at the key input unit 154 (step ST502), the control unit 160 checks whether the detection value of the geomagnetic sensor 158 is in a predetermined abnormal state (step ST504).
Here, the predetermined abnormal state is, for example, any one of 8-bit detection values expressed by integer values from “0” to “255” (that is, geomagnetic detection values on the X axis, Y axis, and Z axis). In any one of the cases, an overflow occurs and the value is the maximum value “255” or the minimum value “0”.
In addition, when a normal range having an upper limit value and a lower limit value is defined, any one of the geomagnetic detection values may be out of the normal range, and an abnormal state may be set.

  When detecting such an abnormal state of the geomagnetic detection value, control unit 160 measures the time during which the abnormal state continues from the time of the detection (step ST506). If the abnormal state continues for a predetermined time (for example, 5 seconds), control unit 160 determines that an offset error has occurred due to magnetization of mobile phone 100 or the like, and executes the above-described offset error correction process (step ST510). ).

After the offset error correction process, the control unit 160 checks whether or not the end of the navigation process is selected. If it is confirmed that the process will continue, the process of steps ST504 to ST510 described above is repeated (step ST512).
In addition, when an abnormal state of the geomagnetic detection value is not detected in step ST504, or when it is determined in step ST508 that the abnormal state of all detection values has been resolved within a predetermined time, the continuation of the navigation process is confirmed in the same manner. Thus, the processes of steps ST504 to ST510 are repeated (step ST512).

As described above, according to the first example of the offset error correction process shown in FIG. 20, when the orientation information is displayed on the display unit 155, the detection value of the geomagnetic sensor 158 becomes a predetermined abnormal state. When the abnormal state continues for a predetermined time, the direction information is corrected. That is, when any one (or a plurality) of detected values of the geomagnetism in the three directions is in a predetermined abnormal state, and this abnormal state continues for a predetermined time, the offset error of the geomagnetic sensor 158 is detected and corrected. (Offset error correction processing) is performed, and the direction is recalculated based on the corrected geomagnetic detection value.
Therefore, by monitoring an abnormality in the detection value of the geomagnetic sensor 158, occurrence of an offset error due to magnetization of the mobile phone 100 or the like is detected and appropriate correction is performed. Can be suppressed.

Further, according to the processing of FIG. 20, when the detected geomagnetism value continues for a predetermined time or more and becomes a predetermined abnormal state, the offset error correction processing is performed.
For this reason, for example, an abnormal state of a temporary geomagnetic detection value caused by the influence of an external magnetic field generated from a building or a train is erroneously determined as an offset error caused by the magnetization of the mobile phone 100, and an inappropriate offset. The case where the error correction process is executed can be reduced.

FIG. 21 is a diagram illustrating an example of an abnormal state of a geomagnetic detection value generated due to the influence of an external magnetic field. In the example of the figure, the geomagnetic detection value in the Z-axis direction is stuck to “0” over a period of 3 to 4 seconds.
If the offset error correction process is executed when an abnormality due to such a temporary external magnetic field is occurring, the offset error cannot be calculated correctly, and the geomagnetic detection value is corrected with an incorrect correction value. As a result, the calculation result of the orientation becomes inaccurate. The inaccurate state of the azimuth continues at least until the next offset error correction process.

As shown in FIG. 21, the abnormal state of the geomagnetic detection value due to the influence of the external magnetic field is usually a transient state within a few seconds, and in many cases returns to a normal state within 5 seconds, for example.
Therefore, as in the process of FIG. 20, the abnormal state and the offset error caused by the influence of the external magnetic field are discriminated according to whether or not the abnormal state continues for a predetermined time or more, and the offset error correction process is performed according to the discrimination result. By controlling the execution of this, inappropriate execution of the correction process can be effectively prevented.

Next, a second example of offset error correction processing will be described.
FIG. 22 is a flowchart illustrating a second example of offset error correction processing in mobile phone 100.

  The difference between the first example (FIG. 20) and the second example (FIG. 22) is that the display unit 155 displays that the accuracy of the direction information is low while the direction information is being corrected. It is in.

That is, after determining that the abnormality of the geomagnetic detection value has continued for a predetermined time or longer in step ST508, the control unit 160 displays on the display unit 155 that the accuracy of the orientation information displayed on the display unit 155 is low (step 155). ST514).
Similarly to the control unit 160, for example, the step ST214 in FIG. 14 described above, the compass image representing the azimuth is moved to the left and right, the shape, color, size, etc. of the compass is changed, or the azimuth accuracy is reduced. The display unit 155 is caused to display information on the deterioration of the orientation accuracy by a method such as displaying an image of

The control unit 160 causes the display unit 155 to display information indicating such a decrease in azimuth accuracy during the offset error correction process (step ST510). Then, when displaying the direction information recalculated based on the corrected geomagnetic detection value on the display unit 155, the display unit 155 displays that the accuracy of the direction has been recovered (step ST516).
For example, in the case where a decrease in azimuth accuracy is displayed by moving the compass image to the left and right, the left and right shake may be stopped. In the case where the deterioration of the orientation accuracy is displayed by changing the shape, color, and size of the compass image, it may be returned to the original state. Alternatively, another image indicating that the accuracy of the direction information has been recovered may be displayed.

  As described above, according to the second example of the offset error correction process shown in FIG. 22, the direction of the azimuth displayed on the display unit 155 is corrected while the direction information accompanying the abnormality of the geomagnetic detection value is being corrected. The user can be notified that the accuracy of the information is low. As a result, the user can correctly grasp whether or not the accuracy of the displayed orientation information is low.

Next, a third example of offset error correction processing will be described.
FIG. 23 is a flowchart illustrating a third example of offset error correction processing in mobile phone 100.

  The difference between the third example (FIG. 23) and the second example (FIG. 22) described above is that the map display is fixed from the heading-up display to the north-up display while the orientation information is being corrected. When the correction of the information is completed, the heading-up display is resumed.

  That is, after determining that the abnormality of the geomagnetic detection value has continued for a predetermined time or longer in step ST508, the control unit 160 fixes the map display from the heading-up display to the north-up display (step ST518), and offset error correction processing ( While performing step ST510), the north-up display is continued. When the direction is recalculated based on the corrected geomagnetic detection value, the north-up display is canceled and the heading-up display is resumed (step ST520).

  As described above, also in the third example of the offset error correction process shown in FIG. 23, the display unit is fixed to the north-up display while correcting the direction information accompanying the abnormality of the geomagnetic detection value. The user can be notified that the accuracy of the orientation information displayed in 155 is low. As a result, the user can correctly grasp whether or not the accuracy of the displayed orientation information is low.

  Next, processing in the case where an error occurs in the detection value of the geomagnetic sensor 158 due to the influence of an external magnetic field and the accuracy of azimuth information decreases will be described.

In general, buildings, trains, and the like include many magnetic field generation sources, and therefore, a large error occurs in the detection value of the geomagnetic sensor 158 due to the influence of external magnetic fields generated by these magnetic field generation sources. If the offset error correction process is executed in such an area, an incorrect offset error is calculated. Therefore, even after leaving the area, it is inaccurate until the offset error correction process is performed again. The direction information remains displayed on the display unit 155.
Therefore, in the processing described below, when it is detected that an area that causes an error in the detection value of the geomagnetic sensor 158 due to the influence of an external magnetic field or the like is detected, the offset error correction processing is prohibited. In addition, the display unit 155 displays that the accuracy of the direction information is lowered, so that the user can determine whether or not to refer to the direction information.

  FIG. 24 is a flowchart illustrating a first example of processing when an error occurs in the geomagnetic detection value due to the influence of an external magnetic field.

  When the start of navigation processing is selected by a key input operation or the like at key input unit 154 (step ST602), control unit 160 determines whether or not the level of the GPS signal received at GPS signal reception unit 151 is lower than a predetermined value. (STEP ST604).

  Normally, the level of the GPS signal becomes very small to a level at which reception is impossible when the mobile phone 100 enters the building. In this example, using this property, it is determined whether or not the mobile phone 100 is inside the building.

When it is detected that the GPS signal has become lower than the predetermined value, control unit 160 determines that mobile phone 100 has entered the interior of the building, and prohibits execution of the above-described offset error correction processing (step ST606). For example, when the correction process is repeated every fixed time, the correction process is not performed even after the fixed time has elapsed.
In this case, control unit 160 causes display unit 155 to display that the accuracy of the direction information has been reduced (step ST608). For example, as in step ST214 of FIG. 14 described above, the compass image representing the azimuth is shaken to the left and right, the shape, color, size, etc. of the compass is changed, or another image representing the deterioration of the azimuth accuracy is displayed. The display unit 155 is caused to display information on the deterioration of the azimuth accuracy by a method such as display.

On the other hand, when it is detected that the GPS signal has become higher than the predetermined value, the control unit 160 determines that the mobile phone 100 is not inside the building, and the execution of the offset error correction process described above is prohibited. If so, this prohibition is canceled (step ST610).
In this case, control unit 160 causes display unit 155 to display that the accuracy of the direction information has been recovered (step ST612). For example, in the case where a decrease in azimuth accuracy is displayed by moving the compass image to the left and right, the left and right shake may be stopped. In the case where the deterioration of the orientation accuracy is displayed by changing the shape, color, and size of the compass image, it may be returned to the original state. Alternatively, another image indicating that the accuracy of the direction information has been recovered may be displayed.

  After step ST608 or ST612, control unit 160 checks whether or not the end of the navigation process is selected, and if it is confirmed that the process will continue, it repeats the processes after step ST604 described above (step ST614).

As described above, according to the first example (FIG. 24) of the processing in the case where an error occurs in the geomagnetic detection value due to the influence of the external magnetic field, when the direction information is displayed on the display unit 155, GPS signal reception is performed. When the level of the GPS signal received by the unit 151 is monitored and it is detected that the level is lower than a predetermined value, it is determined that the mobile phone 100 is inside the building, and the display unit 155 Information indicating that the accuracy of the orientation information is low is displayed on the display unit 155.
As a result, the user can correctly grasp whether or not the accuracy of the displayed orientation information is low. For example, if the accuracy of orientation information is low, the orientation can be determined by another method, such as comparing the information displayed on the map with the surrounding landscape without referring to the orientation displayed on the screen. Since it is clear for the user that a register should be obtained, the ease of use of the navigation function can be improved.

  In addition, since the execution of offset error correction processing is prohibited in inappropriate areas where the offset error cannot be accurately calculated due to the influence of an external magnetic field, such as inside a building, the display of inaccurate orientation is displayed for a long time. Cases that are displayed on the portion 155 can be reduced.

  Next, a second example of processing when an error occurs in the geomagnetic detection value due to the influence of an external magnetic field will be described with reference to the flowchart shown in FIG.

  The difference between the first example (FIG. 24) and the second example (FIG. 25) is that the map display is changed from the heading-up display to the north-up display when it is detected that the GPS signal is lower than a predetermined value. The heading-up display is resumed when it is detected that the GPS signal has become higher than a predetermined value.

  That is, when detecting that the GPS signal has become lower than the predetermined value in step ST604, control unit 160 prohibits the offset error correction process (step ST606) and changes the map display from heading-up display to north-up display. It is fixed (step ST616). If it is detected in step ST604 that the GPS signal is higher than the predetermined value, the prohibition of the offset error correction process is canceled (step ST610), the north-up display is canceled, and the heading-up display is restarted (step ST610). Step ST618).

  As described above, according to the processing of the second example shown in FIG. 25, the map display is fixed to the north-up display in an area where the accuracy of the direction information is lowered due to the influence of the external magnetic field, such as the inside of a building. Thus, it is possible to notify the user that the accuracy of the orientation information displayed on the display unit 155 is low. As a result, the user can correctly grasp whether or not the accuracy of the displayed orientation information is low.

  Next, a third example of processing when an error occurs in the geomagnetic detection value due to the influence of the external magnetic field will be described with reference to the flowchart shown in FIG.

  The difference between the third example (FIG. 26) and the second example (FIG. 25) described above is that the direction calculation processing and the operation of the geomagnetic sensor 158 are performed when it is detected that the GPS signal is lower than a predetermined value. These operations are to be resumed when it is detected that the GPS signal has become higher than a predetermined value.

  That is, when it is detected in step ST604 that the GPS signal has become lower than the predetermined value, control unit 160 fixes the map display from the heading-up display to the north-up display (step ST616), and calculates the direction and The operation of the geomagnetic sensor 158 is stopped (step ST620). If it is detected in step ST604 that the GPS signal is higher than the predetermined value, the north-up display is canceled and the heading-up display is resumed (step ST618), and the azimuth calculation process and the operation of the geomagnetic sensor 158 are performed. It is restarted (step ST622).

  The interior of a building that is difficult to receive GPS signals is an environment that is easily affected by an external magnetic field. However, according to the above-described third example processing shown in FIG. Therefore, the operation of the geomagnetic sensor 158 is stopped according to the level of the GPS signal, so that the wasteful power supply to unused circuits can be suppressed and the power consumption can be reduced.

  Next, a fourth example of processing in the case where an error occurs in the geomagnetic detection value due to the influence of an external magnetic field will be described with reference to the flowchart shown in FIG.

  The difference between the fourth example (FIG. 27) and the third example (FIG. 26) described above is that, when it is detected that the GPS signal has become higher than a predetermined value, the heading is increased after the calculated direction value is stabilized. It is to resume the display.

  That is, after detecting that the GPS signal has become higher than the predetermined value in step ST604 and resuming the direction calculation processing and the operation of the geomagnetic sensor 158 (step ST622), the control unit 160 stabilizes the direction calculation value. It is determined whether or not (step ST624). For example, the control unit 160 determines that the calculated value of the azimuth is stable when the fluctuation range in the predetermined time of the calculation result of the azimuth is within a predetermined range. Then, after determining that the calculated value of the azimuth is stable, the north-up display is canceled and the heading-up display is resumed (step ST618).

  As described above, according to the process of the fourth example shown in FIG. 27, when it is determined that the signal level of the GPS signal is higher than a predetermined value and the mobile phone 100 is out of the building or the like, the direction is calculated. The heading up display is resumed after the value is confirmed to be stable. Therefore, for example, it is possible to prevent information with a low accuracy from being displayed on the display unit 155 in a state in which the fluctuation of the geomagnetic detection value due to the magnetic field from the building is large immediately after going out of the building.

  Next, a fifth example of processing in the case where an error occurs in the geomagnetic detection value due to the influence of an external magnetic field will be described with reference to the flowchart shown in FIG.

In the processes of the first to fourth examples (FIGS. 24 to 27) described above, based on the reception level of the GPS signal, whether or not the mobile phone 100 is inside the building, that is, the geomagnetism due to the influence of the external magnetic field. It is determined whether or not the vehicle is in an area where errors are likely to occur.
In the process of the fifth example (FIG. 28) to be described next, the current location of the mobile phone 100 is included in the accuracy-decreased region where the accuracy of the detection value of the magnetic sensor 158 is reduced based on information registered in the storage unit 152 in advance. If it is determined that it is included, the offset error correction process is prohibited. In addition, the display unit 155 displays that the accuracy of the direction information is lowered, so that the user can determine whether or not to refer to the direction information.

  First, when the start of the navigation process is selected by a key input operation or the like in the key input unit 154 (step ST702), the control unit 160 determines whether the current location of the terminal is included in the reduced accuracy area registered in the storage unit 152. It is determined whether or not (step ST704).

For example, the information on the reduced accuracy area registered in the storage unit 152 includes an identification number of the map sent from the navigation server device 402, and information on the coordinates of the reduced accuracy area on the map (for example, the map according to the coordinate range). Etc.), and the information indicating the accuracy-decreased area above.
First, the control unit 160 searches the information on the same identification number as that of the currently displayed map from the information on the reduced accuracy area registered in the storage unit 152. If information of the same identification number exists as a result of the search, it is further determined whether or not the current location of the mobile phone 100 is included in the coordinate range of the reduced accuracy area on the map indicated by the coordinate information. When the current location is included in the coordinate range, the control unit 160 determines that the current location of the mobile phone 100 is included in the reduced accuracy area.

If it is determined that the current location is included in the reduced accuracy region, control unit 160 prohibits execution of the above-described offset error correction processing (step ST706). For example, when the correction process is repeated every fixed time, the correction process is not performed even after the fixed time has elapsed.
In this case, control unit 160 also causes display unit 155 to display that the accuracy of the direction information has decreased (step ST708). For example, as in step ST214 of FIG. 14 described above, the compass image representing the azimuth is shaken to the left and right, the shape, color, size, etc. of the compass is changed, or another image representing the deterioration of the azimuth accuracy is displayed. The display unit 155 is caused to display information on the deterioration of the azimuth accuracy by a method such as display.

On the other hand, if it is determined that the current location is outside the area of reduced accuracy, control unit 160 cancels the prohibition if execution of the above-described offset error correction process is prohibited (step ST710).
In this case, control unit 160 also causes display unit 155 to display that the accuracy of the direction information has been recovered (step ST712). For example, in the case where a decrease in azimuth accuracy is displayed by moving the compass image to the left and right, the left and right shake may be stopped. In the case where the deterioration of the orientation accuracy is displayed by changing the shape, color, and size of the compass image, it may be returned to the original state. Alternatively, another image indicating that the accuracy of the direction information has been recovered may be displayed.

  After step ST708 or ST712, the control unit 160 checks whether or not the end of the navigation process is selected. If it is confirmed that the process will continue, the control unit 160 repeats the processes after step ST704 (step ST714).

As described above, according to the fifth example (FIG. 28) of the processing in the case where an error occurs in the geomagnetic detection value due to the influence of the external magnetic field, when the orientation information is displayed on the display unit 155, the mobile phone 100 It is determined whether or not the current location is included in the reduced accuracy area registered in the storage unit 152. As a result of this determination, when it is determined that the current location is included in the reduced accuracy area, information indicating that the accuracy of the orientation information on the display unit 155 is low is displayed on the display unit 155.
Thereby, since the user can correctly grasp whether or not the accuracy of the displayed orientation information is low, the ease of use of the navigation function can be improved.

  In addition, since the execution of the offset error correction process is prohibited in an area where the offset error cannot be accurately calculated due to the influence of the external magnetic field, an incorrect azimuth display is displayed on the display unit 155 for a long time. Can be reduced.

  Next, a sixth example of processing when an error occurs in the geomagnetic detection value due to the influence of an external magnetic field will be described with reference to the flowchart shown in FIG.

  The difference between the above-described fifth example (FIG. 28) and the sixth example (FIG. 29) is that the map display is fixed from the heading-up display to the north-up display when it is determined that the current location is included in the reduced accuracy area. Then, when it is determined that the current location is out of the reduced accuracy region, the heading-up display is resumed.

  That is, if controller 160 determines in step ST704 that the current location of mobile phone 100 is included in the reduced accuracy area, control unit 160 prohibits the offset error correction process (step ST706) and changes the map display from heading-up display to north-up. The display is fixed (step ST716). If it is determined in step ST704 that the current location is out of the reduced accuracy region, the prohibition of the offset error correction process is canceled (step ST710), the north-up display is canceled, and the heading-up display is resumed (step ST718). .

  As described above, according to the process of the sixth example shown in FIG. 29, the map display is fixed to the north-up display in an area where the accuracy of the direction information is reduced due to the influence of the external magnetic field, such as the inside of a building. Thus, it is possible to notify the user that the accuracy of the orientation information displayed on the display unit 155 is low. As a result, the user can correctly grasp whether or not the accuracy of the displayed orientation information is low.

  Next, a seventh example of processing in the case where an error occurs in the geomagnetic detection value due to the influence of an external magnetic field will be described with reference to the flowchart shown in FIG.

  The difference between the above-described sixth example (FIG. 29) and the seventh example (FIG. 30) is that, when it is determined that the mobile phone 100 has entered an area of reduced accuracy based on the information in the storage unit 152, the direction calculation processing In addition, the operation of the geomagnetic sensor 158 is stopped, and when it is determined that the mobile phone 100 is out of the area of reduced accuracy, these operations are resumed.

  That is, if controller 160 determines in step ST704 that the current location of mobile phone 100 is included in the area of reduced accuracy, control unit 160 fixes the display of the map from heading-up display to north-up display (step ST716), and calculates the direction. Processing and the operation of the geomagnetic sensor 158 are stopped (step ST720). If it is determined in step ST704 that the current location is out of the reduced accuracy region, the north-up display is canceled and the heading-up display is resumed (step ST718), and the direction calculation processing and the operation of the geomagnetic sensor 158 are resumed (step ST718). Step ST722).

  As described above, according to the process of the eighth example shown in FIG. 30, the operation of the geomagnetic sensor 158 is stopped in an area where the accuracy of the orientation information is lowered due to the influence of the external magnetic field, so that it is wasteful to an unused circuit. Therefore, it is possible to reduce power consumption by suppressing the supply of unnecessary power.

  Next, an eighth example of processing in the case where an error occurs in the geomagnetic detection value due to the influence of an external magnetic field will be described with reference to the flowchart shown in FIG.

  The difference between the above-described seventh example (FIG. 30) and the eighth example (FIG. 31) is that when it is determined that the mobile phone 100 is out of the area with reduced accuracy, the heading is increased after the calculated value of the azimuth is stabilized. It is to resume the display.

  That is, control unit 160 determines in step ST704 that the current location of mobile phone 100 is out of the reduced accuracy region, restarts the direction calculation processing and the operation of geomagnetic sensor 158 (step ST722), and then calculates the direction. It is determined whether or not the value is stable (step ST724). For example, the control unit 160 determines that the calculated value of the azimuth is stable when the fluctuation range in the predetermined time of the calculation result of the azimuth is within a predetermined range. Then, after determining that the calculated value of the azimuth is stable, the north-up display is canceled and the heading-up display is resumed (step ST718).

  As described above, according to the processing of the eighth example shown in FIG. 31, when it is determined that the current location of the mobile phone 100 is out of the accuracy-decreasing region, the heading is confirmed after confirming that the calculated value of the bearing is stable. Up display is resumed. Therefore, for example, immediately after leaving the area with reduced accuracy, it is possible to prevent information with a low accuracy from being displayed on the display unit 155 when a change in the geomagnetic detection value due to a magnetic field from a building or the like remains. .

  Next, in the processing of the fifth to eighth examples (FIGS. 28 to 31) described above, processing for registering the reduced accuracy area in the storage unit 152 will be described with reference to the flowchart of FIG.

When the start of the navigation process is selected by a key input operation or the like at the key input unit 154 (step ST732), the control unit 160 checks whether the detection value of the geomagnetic sensor 158 is in a predetermined abnormal state (step ST734).
Here, the predetermined abnormal state is the same as that described in the offset error correction process of FIG. 20, for example. That is, an overflow has occurred in any one of the 8-bit detection values represented by integer values from “0” to “255”, and any one of the geomagnetic detection values is out of the predetermined normal range. Is detected as an abnormal condition.

  When detecting such an abnormal state of the geomagnetic detection value, control unit 160 measures the time during which the abnormal state continues from the time of the detection (step ST736). When the abnormal state ends within a predetermined time (for example, 5 seconds), the control unit 160 determines that an error has occurred in the geomagnetism detection location due to the external magnetic field (step ST738), and the storage unit 152 uses the current location as the accuracy reduction region. (Step ST740).

  The registration of the reduced accuracy area in the storage unit 152 includes the identification number of the map displayed when the abnormality of the geomagnetic detection value is detected, and information on the coordinates on the map where the abnormality has occurred (for example, the abnormality occurrence point) The coordinate range of an area of several meters square is associated with each other and stored in a predetermined accuracy-reduced area registration data table assigned to the storage unit 152.

Note that an upper limit may be set for the number of areas with reduced accuracy registered in the storage unit 152. In this case, when the number of accuracy-decreasing areas registered in the storage unit 152 reaches this upper limit, the control unit 160, when registering a new accuracy-decreasing area, from among the information on the registered accuracy-decreasing areas. The oldest information may be deleted.
Thereby, it is possible to prevent the storage area of the storage unit 152 from being consumed indefinitely by the registration information of the reduced accuracy area, and it is possible to improve the reliability of the information of the reduced accuracy area by leaving the latest information.

After registering the reduced accuracy area in the storage unit 152, the control unit 160 checks whether or not the end of the navigation process is selected (step ST742), and if it is confirmed that the process will continue, the above-described steps ST734 to ST740 are performed. Repeat the process.
In addition, when an abnormal state of the geomagnetism detection value is not detected in step ST734, or when it is determined in step ST738 that the abnormal state of the geomagnetism detection value has continued for a predetermined time or more, after confirming the continuation of the navigation process, The processes in steps ST734 to ST740 are repeated.

  The preferred embodiments of the present invention have been described so far, but the present invention is not limited to the above-described embodiments, and includes various variations.

  In the above-described embodiment, the first to sixth examples as the azimuth calculation processing, the first to third examples as the offset error correction processing, and the first to third processings when an error occurs in the geomagnetic detection value due to the influence of the external magnetic field. Although the eighth example has been shown, the embodiment of the present invention includes a form in which at least some of these processing examples are arbitrarily combined.

  In the above-described embodiment, an example in which geomagnetism in three directions is detected by the geomagnetic sensor 158 has been described.

  In the above-described embodiment, for example, in step ST208 of FIG. 14 and the like, an example in which the accuracy of the orientation information is reduced is displayed on the display unit 155. However, the present invention is not limited to this. When the direction information is corrected while performing the correction, it may be displayed on the display unit 155 that the correction is being performed. Or you may display on the display part 155 the information which shows both during the precision fall and correction | amendment.

  Further, instead of displaying information such as when accuracy is being reduced or during correction, the display of orientation information may be simply stopped. In this case, when the correction of the azimuth is completed (or out of the area where the accuracy is lowered), the display of the azimuth information may be resumed to indicate to the user that the accuracy of the azimuth information has been restored. .

  In steps ST616 and ST618 of FIGS. 26 and 27, the north-up display is fixed and released. However, the present invention is not limited to this. For example, as in steps ST608 and ST612 of FIG. May be displayed.

  In steps ST716 and ST718 of FIGS. 30 and 31, the north-up display is fixed and released. However, the present invention is not limited to this. For example, as in steps ST708 and ST712 of FIG. May be displayed.

In the fifth to eighth examples (FIGS. 28 to 31), which are processes in the case where an error occurs in the geomagnetic detection value due to the influence of the external magnetic field, information on the accuracy-decreasing area is acquired from the data table of the storage unit 152. However, the present invention is not limited thereto, and may be acquired from a server device connected via the wireless communication unit 150, for example.
That is, the control unit 160 acquires information indicating whether or not the current location of the mobile phone 100 is included in the accuracy-decreased region from the predetermined server device via the wireless communication unit 150, and the current location is the accuracy in the acquired information. In the case where it is indicated that it is included in the lowered area, the offset error correction process may be prohibited.

In the above-described embodiment, map rotation processing (for example, heading-up display) is performed on the mobile phone 100. However, the present invention is not limited to this, and for example, the mobile phone 100 indicates the map display direction with respect to the navigation server device 402. The map information may be requested and the navigation server device 402 may generate map information in a direction corresponding to the request from the mobile phone 100 and provide the map information to the mobile phone 100.
That is, the control unit 160 may perform processing for acquiring map image information corresponding to the orientation calculated based on the detected geomagnetism value from the navigation server device 402 and displaying it on the display unit 155.
During this process, if a decrease in the detection accuracy of the geomagnetic detection value is detected, for example, because the level of the GPS signal becomes lower than a predetermined value, the control unit 160 is set in advance regardless of the calculated orientation. The navigation server device 402 may be requested to obtain image information of a map in a different direction, and may be displayed on the display unit 155.

  In the above-described embodiment, the position calculation process according to the GPS signal is performed by the GPS server device 401. However, the present invention is not limited to this, and the mobile phone 100 may calculate the position from the GPS signal.

  In the above-described embodiment, the map information is acquired from the navigation server device 402. However, the present invention is not limited to this, and the map information may be stored in a storage device inside the mobile phone 100.

In the above-described embodiment, an example in which the processing of the control unit 160 is executed based on a program by a computer has been described. However, at least a part of these processing can be executed by hardware without using a computer. .
Conversely, at least a part of processing in units other than the control unit 160 may be executed by the computer of the control unit 160.

  Further, the mobile communication terminal of the present invention is not limited to a mobile phone. For example, the present invention can be widely applied to portable terminal devices having a communication function such as PDA (personal digital assistants).

It is a block diagram which shows the structural example of the system for acquiring the information of geographical location and map in the mobile telephone which concerns on embodiment of this invention. It is a perspective view of the mobile phone in an open state. It is a perspective view from one side of a cellular phone in a closed state. It is a perspective view from the other side of a cellular phone in a closed state. It is a perspective view which shows the board | substrate mounting state in the inside of a board | substrate mounting housing | casing. It is a block diagram which shows the structural example of the mobile telephone which concerns on embodiment of this invention. It is the flowchart which illustrated an example of the GPS signal reception process in a mobile telephone. 5 is a flowchart illustrating an example of navigation processing in a mobile phone. It is a figure which shows an example of the map information transmitted from a navigation server apparatus. 5 is a flowchart illustrating an example of display image rotation processing in a mobile phone. It is a figure for demonstrating the calculation method of an azimuth. It is the flowchart which illustrated the 1st example of the azimuth | direction calculation process in a mobile telephone. It is a figure which shows an example of the data for correction | amendment. It is the flowchart which illustrated the 2nd example of the azimuth | direction calculation process in a mobile telephone. 12 is a flowchart illustrating a third example of orientation calculation processing in a mobile phone. 10 is a flowchart illustrating a fourth example of direction calculation processing in a mobile phone. 10 is a flowchart illustrating a fifth example of orientation calculation processing in a mobile phone. It is a figure which shows an example of the time change of the geomagnetic sensor detection value according to the presence or absence of mounting | wearing of a memory card. 12 is a flowchart illustrating a sixth example of orientation calculation processing in a mobile phone. 6 is a flowchart illustrating a first example of offset error correction processing when an abnormal state occurs in a geomagnetic detection value. It is a figure which shows an example of the abnormal state of the geomagnetic detection value produced by the influence of an external magnetic field. It is the flowchart which illustrated the 2nd example of the offset error correction process in a mobile telephone. 10 is a flowchart illustrating a third example of offset error correction processing in a mobile phone. It is the flowchart which illustrated the 1st example of the process in case an error arises in a geomagnetic detection value by the influence of an external magnetic field. It is the flowchart which illustrated the 2nd example of the process in case an error arises in a geomagnetic detection value by the influence of an external magnetic field. It is the flowchart which illustrated the 3rd example of the process in case an error arises in a geomagnetic detection value by the influence of an external magnetic field. It is the flowchart which illustrated the 4th example of the process in case an error arises in a geomagnetic detection value by the influence of an external magnetic field. It is the flowchart which illustrated the 5th example of the process in case an error arises in a geomagnetic detection value by the influence of an external magnetic field. It is the flowchart which illustrated the 6th example of the process in case an error arises in a geomagnetic detection value by the influence of an external magnetic field. It is the flowchart which illustrated the 7th example of the process in case an error arises in a geomagnetic detection value by the influence of an external magnetic field. It is the flowchart which illustrated the 8th example of the process in case an error arises in a geomagnetic detection value by the influence of an external magnetic field. FIG. 32 is a flowchart illustrating an example of processing for registering a reduced accuracy area in a storage unit in the processing illustrated in FIGS. 28 to 31.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... 1st housing | casing, 3 ... 2nd housing | casing, 4 ... Movable mechanism part, 21 ... Display panel, 100 ... Mobile phone, 200 ... GPS satellite, 300 ... Base station, 401 ... GPS server apparatus, 402 ... Navigation Server device 150... Wireless communication unit 151... GPS signal receiving unit 152. Storage unit 153 Open / close determination unit 154 Key input unit 155 Display unit 156 Audio processing unit 157 Imaging unit 158 ... Geomagnetic sensor, 159 ... Memory card part, 160 ... Control part.

Claims (7)

A geomagnetic sensor for detecting geomagnetism;
Position information acquisition means for acquiring information related to the geographical position of the current location;
Display means;
The geographical direction is calculated based on the detection value of the geomagnetic sensor, the calculated direction information, and the geographical position information of the current location specified based on the position information acquired by the position information acquisition means. Control means for performing processing to be displayed on the display means, and offset error correction processing for detecting and correcting an offset error of the geomagnetic sensor;
A mobile communication terminal having
Storage means for registering information related to the accuracy-decreasing area where the accuracy of the detection value of the geomagnetic sensor is reduced;
The control means determines whether or not the current location specified based on the position information is included in the reduced accuracy area registered in the storage means, and determines that the current location is included in the reduced accuracy area, A portable communication terminal characterized by prohibiting the offset error correction process. When the detection value of the geomagnetic sensor becomes a predetermined abnormal state within a predetermined time, the control means includes a point specified based on the position information acquired when the abnormality of the detection value occurs. 2. The mobile communication terminal according to claim 1, wherein the predetermined range is registered in the storage unit as the accuracy-reduced area. Having wireless communication means;
The control means is image information of a map around the current location specified based on the position information acquired by the position information acquisition means, and the image information of the map to which a predetermined identification number is assigned When processing for obtaining from the information provider via the wireless communication means and displaying on the display means is performed, and the area with reduced accuracy is registered in the storage means, the abnormality is detected when the detected value is abnormal. The mobile communication according to claim 2, wherein an identification number of the map displayed on the display means and information on coordinates on the map relating to a point where the abnormality of the detected value has occurred are registered in the storage means. Terminal. When the number of accuracy-decreasing areas registered in the storage unit reaches a predetermined upper limit, the control unit registers the newest accuracy-decreasing area, and is the oldest among the registered accuracy-decreasing area information. The mobile communication terminal according to claim 2 or 3, wherein the information is deleted. A geomagnetic sensor for detecting geomagnetism;
Position information acquisition means for acquiring information related to the geographical position of the current location;
Display means;
The geographical direction is calculated based on the detection value of the geomagnetic sensor, the calculated direction information, and the geographical position information of the current location specified based on the position information acquired by the position information acquisition means. Control means for performing processing to be displayed on the display means, and offset error correction processing for detecting and correcting an offset error of the geomagnetic sensor;
A mobile communication terminal having
Having wireless communication means;
The control means obtains information indicating whether or not the current location specified based on the position information is included in a reduced accuracy region where the accuracy of the detection value of the geomagnetic sensor is reduced from a predetermined information provider. The mobile communication terminal, wherein the offset error correction processing is prohibited when information indicating that the current location is included in the reduced accuracy area is acquired through a means. Geomagnetic sensor for detecting geomagnetism, position information acquisition means for acquiring information related to the geographical position of the current location, information on geographical orientation calculated based on the detection value of the geomagnetic sensor, and position information acquisition means An error correction method for a geomagnetic sensor for correcting an error of the geomagnetic sensor in a portable communication terminal having display means for displaying information on a geographical position of a current location specified based on position information acquired in ,
A first step of registering in the storage means of the mobile communication terminal, information relating to the accuracy-decreasing area where the accuracy of the detection value of the geomagnetic sensor decreases;
A second step of determining whether or not the current location specified based on the position information is included in the reduced accuracy area registered in the storage means in the first step;
And a third step of prohibiting a process of detecting and correcting an offset error of the geomagnetic sensor when it is determined in the second step that the current location is included in the accuracy-decreasing region. Sensor error correction method. Geomagnetic sensor for detecting geomagnetism, position information acquisition means for acquiring information related to the geographical position of the current location, information on geographical orientation calculated based on the detection value of the geomagnetic sensor, and position information acquisition means An error correction method for a geomagnetic sensor for correcting an error of the geomagnetic sensor in a portable communication terminal having display means for displaying information on a geographical position of a current location specified based on position information acquired in ,
Information indicating whether or not the current location specified based on the position information is included in an accuracy-decreasing area where the accuracy of the detection value of the geomagnetic sensor is reduced is obtained from a predetermined information provider by the wireless communication means of the mobile communication terminal. A first step obtained through
A second step of prohibiting a process of detecting and correcting an offset error of the geomagnetic sensor when information indicating that the current location is included in the reduced accuracy area is acquired in the first step. An error correction method for a geomagnetic sensor.

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