JP4199290B2 - Navigation device and position calculation method - Google Patents

Description

  The present invention relates to a navigation device having a mobile phone or the like as a terminal, and a position information transmission unit that transmits information on the current position to a navigation device located within the range using a weak radio wave having a narrow radio wave reach. The present invention relates to a navigation device that acquires position information and a position calculation method, and in particular, when the navigation device enters and leaves a communication area that is a radio wave reach of the position information transmission unit, the accurate position and orientation of the navigation device are determined. The present invention relates to a navigation device and a position calculation method that can be calculated.

  2. Description of the Related Art In recent years, there has been a remarkable development in mobile terminals such as mobile phones. A comprehensive mobile terminal apparatus that performs data communication by connecting to various servers via a network such as the Internet from a terminal apparatus for simple calls. As a result, the penetration rate of mobile terminals has become extremely high. In particular, positioning units that are currently installed only on some mobile phones, such as GPS receivers that receive and measure signals from GPS (Global Positioning System) satellites, are called the third generation. Mobile phones tend to be installed in all models.

  Various technologies have been proposed for using mobile terminals having such a positioning function. For example, a navigation device (car navigation) for automobiles has been developed, and map / route information is obtained using a mobile phone as a terminal. A communication navigation system for pedestrians distributed from an information distribution server (route search server) has been proposed. In addition, a payment system using a mobile phone as a terminal and various Internet transaction systems have been proposed. Recently, mobile phones are increasingly used for reporting in the event of an incident or accident, and the need for technology for identifying the reporting location is increasing. Attempts have also been made to identify the location of the elderly using a mobile phone positioning system, and its use is expected to continue to expand.

  For example, the Ministry of Land, Infrastructure, Transport and Tourism provides route guidance to pedestrians including persons with disabilities in Non-Patent Document 1 (report titled “Pedestrian ITS (Intelligent Transport System) and High-precision Positioning Technology”, March 2002). A skeleton of a guidance system is disclosed. Non-Patent Document 1 discloses various techniques for a pedestrian to transmit position information to a portable terminal (an instrument such as a cane). For example, in addition to a technique for installing a GPS receiver, a technique for installing a wireless ID tag in a walking space and a technique for installing a tag using Bluetooth (registered trademark) are shown. In the tag, unique identification information is recorded, and based on this information, the location of the mobile terminal existing in the range centered on the tag installation position is determined (position is determined). On the other hand, the Ministry of Internal Affairs and Communications is studying the function of notifying the sender location information in emergency calls from mobile phones, and the need to establish a positioning system for this is also increasing.

  A technology for positioning the current position of a mobile terminal equipped with a GPS receiver has been put into practical use in car navigation systems and communication-type navigation systems, and positioning accuracy has been improved, but it can receive signals from GPS satellites. Because it is a premise, it is currently not suitable for positioning in underground malls and buildings. On the other hand, the technology that installs tags using Bluetooth (registered trademark) in the walking space is to place the location information on the mobile terminal by installing the tags at appropriate intervals along the route in the underground city or building. It can be provided and can be used as a technology to complement the GPS positioning system.

  Bluetooth (registered trademark) is a wireless communication method using relatively weak radio waves, and the current radio wave reachable range (communication area: called piconet) is about 10 m in radius. The transmission unit using this communication system is provided with an ID tag (unique ID information recorded in a memory such as a ROM), and transmits the information recorded in the ID tag to the portable terminal wirelessly. The portable terminal can be equipped with a receiver that supports this wireless communication method, and a system can be configured in which the received ID information is sent to the position information center and the position of the portable terminal is specified. In this case, in order to prevent radio wave interference, the transmitter units need only be installed at a radius of 10 m (diameter 20 m), and the positioning accuracy of the position is higher than the accuracy of the current GPS positioning, and a small position range can be specified. can do.

  On the other hand, as a technique for specifying the position of a mobile terminal such as a mobile phone, for example, there is a position information providing service disclosed in the following Patent Document 1 (Japanese Patent Laid-Open No. 2002-109679). In this location information providing service system, a traveler's passage in a specific area is configured as a passage network by physical means installed on the road, and information communication enabling wireless communication access to nodes and terminal points of the passage network This is an information providing system provided with means for providing information to travelers. Further, in this system, each information communication means of each node of the aisle network, the terminal point and the traveler has an individual number, and an individual signal corresponding to the individual number is transmitted to the central processing unit, In addition, a traveler's location information database is generated appropriately, and a traveler's location information providing service utilizing the location information database can be provided to travelers or third parties via the Internet. is there.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2003-344093) below discloses a route guidance system that guides a route to a mobile terminal in a place where a GPS signal cannot be received such as an underground shopping street. In other words, this route guidance system allows the operator as a pedestrian to properly recognize the current location even in places where it is difficult to recognize the current location, such as an underground shopping center, and easily grasps the route to the destination. The purpose is to be able to. The route guidance system includes a route search unit that searches for an underground route based on map data, and route guidance data that creates guide data for guiding the searched underground route based on map data and guidance signboard data. It is comprised from the preparation part and the transmission data preparation part which produces the transmission data which display the character string of a guidance signboard on a display screen based on the produced guidance data.

  Similarly, the following Patent Document 3 (Japanese Patent Laid-Open No. 2003-240591) is disclosed as an indoor route search apparatus having a hierarchy. The route search device disclosed in Patent Document 3 stores electronic map data that holds a route data storage unit that stores node data and link data, and a cost data storage unit that stores cost data (required time). This is used to search for a route. The link data is provided with a rank parameter to enable searching for a route between different hierarchies. This enables, for example, a route search from a starting point such as an entrance to a destination on an upper floor in a department store or a supermarket having a plurality of floors, or a self-propelled multilevel parking garage or the like. .

  As one application for using the position information obtained by the position information providing system or the GPS positioning system as described above, the information on the departure point and the destination is sent from the portable terminal to the information distribution server, and the information distribution server uses the road network and traffic. 2. Description of the Related Art Navigation devices that search for and guide the shortest route from network data have been put into practical use. As a route search method in such a navigation system, the Dijkstra method (label determination method) is used. The following Patent Document 4 (Japanese Patent Laid-Open No. 2001-165681) discloses an outline of a route search method using the Dijkstra method. A technique for detecting the traveling direction of a mobile terminal such as a mobile phone is disclosed in the following Patent Document 5 (Japanese Patent Application Laid-Open No. 8-278137).

  As described above, even if a GPS receiver is mounted on a portable terminal and positioning is possible, the position of the portable terminal is not used in places where GPS satellite signals cannot be received, such as inside buildings or underground shopping streets. It cannot be specified. For this reason, in the route guidance system disclosed in Patent Document 2, route guidance is performed using guide signs installed in passages, exits, and the like in underground malls. However, this guidance system has a problem in that it cannot always provide the shortest route guidance because it can only guide the route connecting the installation locations of the guidance signboards.

  Further, in the route search device disclosed in Patent Document 3, the route data storage unit storing node data related to the nodes set to the routes connecting the floors and the routes connecting the floors, link data including the floor parameters, and cost data The route search is performed using the electronic map data that holds the cost data storage unit that stores the (required time). This makes it possible to search for routes that cross floors, but in order to provide appropriate guidance (guidance) to the user at the corners and stairs of the guide route, it is necessary to be able to determine the location where the mobile terminal is located indoors A portable terminal positioning means is required.

  Even if GPS satellite signals can be received inside the building, the position information obtained by the GPS positioning system is only the latitude and longitude, and the floor (floor) where the mobile terminal is located is different inside the building and in the underground shopping center. However, there is a problem that the positioning result is the same latitude and longitude, and the floor cannot be specified.

  In addition, when installing a facility that generates a signal equivalent to a GPS satellite signal inside a building, or a tag using the above-described wireless ID tag or Bluetooth (Bluetooth), along a route, There is a problem that the infrastructure construction cost for installing ID tags and the like becomes enormous.

The inventor of the present application has already filed a patent application for the invention of Japanese Patent Application No. 2004-161873 for the purpose of solving the above problems.
In the invention shown in Japanese Patent Application No. 2004-161873 (hereinafter simply referred to as “prior application”), a position information transmission unit body composed of a power supply unit, a communication unit, and a microcomputer including position information storage means is used as a lighting fixture. The position information is transmitted to the navigation device by installing it at a predetermined interval using a mounting outlet, an outlet for installing the lighting fixture, and the like at the node positions constituting the route. That is, the location information storage means stores the latitude, longitude, and floor information of the location where the location information transmission unit is installed as location information, and the communication unit stores the location information as a radio wave arrival range (communication). Information on the current position is transmitted to a navigation device located in the communication area using a weak radio wave having a narrow area.

  The position information transmission unit of the prior application and the use form of the position information will be described in detail with reference to the drawings.

  That is, the position information transmission unit 100 includes a position information transmission unit main body 102 and a lighting fixture main body 202 composed of a fluorescent lamp or a lamp made of a light bulb as shown in FIGS. 11 (a) and 11 (b). The position information transmission unit main body 102 is attached to the lamp support 206 of the luminaire main body 202. As shown in FIG. 11C, the position information transmission unit main body 102 includes a power supply unit 104, a communication unit (communication module) 106, and a microcomputer (microcomputer) 108. The power supply unit 104 includes a lighting fixture main body. A power line is connected from a base 204 of 202. This position information transmission unit 100 is inserted into an illumination socket provided on the ceiling or wall. When the lamp 208 is formed of a fluorescent tube as shown in FIG. 11A, there is an inverter circuit that uses an AC voltage supplied from the base 204 as a power source, and a DC power source is also prepared for the control circuit. Therefore, the power supply unit 104 may be connected thereto. Further, as shown in FIG. 11B, when the lamp 208 is constituted by a light bulb, an AC voltage-DC voltage conversion circuit corresponding to an inverter circuit may be relayed and connected to the power supply unit 104.

  The position information transmission unit main body 102 is configured around a microcomputer (microcomputer) 108. As is well known, the microcomputer 108 is composed of a processor, ROM, EEPROM, and the like. The communication unit 106 is controlled by a control program recorded in the ROM, and information received from the communication unit 106 is recorded in the EEPROM. In addition, the position information recorded in the EEPROM is transmitted via the communication unit 106. In the EEPROM, information on the latitude, longitude, and floor of the location where the position information transmission unit 100 is installed is recorded as position information. The communication unit 106 is, for example, a communication module that is compatible with a communication method using Bluetooth (registered trademark). Bluetooth (registered trademark) is a wireless communication method using relatively weak radio waves, and the current radio wave reachable range (communication area) has a radius of about 10 m. Accordingly, when the navigation device is located within a radius of 10 m from the installation location of the location information transmission unit 100, the latitude, longitude, and floor information of the installation location recorded in the EEPROM can be transmitted to the navigation device as location information. .

  In addition to latitude, longitude, and floor information, or in place of floor information, the location information recorded in the EEPROM can be added with a room number in the case of a building such as a hotel, apartment house, or office. . In this case, the location information acquired by the mobile terminal includes a room number, which is an effective means for specifying a transmission place when an emergency call is received from a mobile phone as a mobile terminal, for example.

  When the position information transmission unit main body 102 is attached to the luminaire main body 202 in this way, the existing power supply unit such as a socket, a ceiling, and an outlet for installing the luminaire is used, so that the wiring facility of the power supply system can be provided. A location information transmission unit can be easily installed without preparation. In addition, it is necessary to install a large number of location information transmission units 100 at regular intervals inside the building or in the underground shopping street, but the power supply unit 104, communication unit 106, microcomputer 108, etc. that constitute the location information transmission unit main body 102 also reduce costs. As a result, it can be obtained at a low cost, and further cost reduction by mass production becomes possible.

  In addition, a socket for a lighting fixture in an underground shopping center or a building is normally supplied with power, and can be operated stand-alone simply by installing the position information transmission unit main body 102. Therefore, when installing a large number of location information transmission units 100, it is not necessary to store the location information of the installation location in each location information transmission unit at the manufacturing site, and the installation location and each location information in an underground mall or building to be installed separately. It is also possible to create a database on a PC (personal computer) and store it, and write it to each position information transmission unit from the PC at the installation site.

  FIG. 12 is a conceptual diagram showing a state in which a large number of such position information transmission units 100 are installed at predetermined intervals using an illumination power source in an underground shopping center or a building. That is, the position information transmission units 100a to 100c are installed in the communication areas 100A to 100C at predetermined intervals in the structure. When the position information transmission units 100a to 100c are adapted to the above-described communication method using Bluetooth (registered trademark), the radio wave reachable range is about 10 m in radius. Accordingly, each of the communication areas 100A to 100C has a diameter of about 20 m, and the position information transmission units 100a to 100c are installed at the center thereof. Since the installation interval of sockets for lighting fixtures in underground shopping malls and buildings is in units of several meters, the communication areas 100A to 100C should be separated and installed at intervals that do not cause radio wave interference of the position information transmission units 100a to 100c. Is easy.

  When the navigation device 30 enters the range of the communication area 100A, the location information from the location information transmission unit 100a, that is, the latitude, longitude, and floor information of the place where the location information transmission unit 100a is installed is transmitted to the navigation device 30. The navigation device 30 can notify the route search server and other servers of the current position. In this case, the navigation device 30 and the route search device need to be in a state in which communication is possible via a network such as the Internet. At present, relay facilities and base stations are often installed in subway facilities, underground malls and buildings so that mobile phones can be used. Data communication is possible between the navigation device and the route search server.

  FIG. 13 is a diagram illustrating a floor layout in an underground shopping center where a position information transmission unit 100 is installed, and 1F to B2 are floors of the building, 1F is the first floor above ground, B1 is the first floor below, and B2 is It shows the second basement. In such a building, there are routes (passages) in the floor and routes (stairs, elevators, escalators, etc.) that connect the floors. Similar to the map data used for normal navigation, route search and route guidance are possible by creating a route for each floor as map data.

  The only difference from the route search in normal navigation is that a floor and a route moving in the vertical direction exist in a part of the route. Therefore, node IDs are determined by setting the nodes (including intersections on roads) where the starting and ending points of all routes, including the route moving in the vertical direction, and the direction in which the traveling direction in the horizontal and vertical directions changes (corresponding to intersections on roads) as nodes. If the travel time (cost) for each link to be linked is stored in a database, the shortest route from the starting location to the target location can be searched using the Dijkstra method disclosed in Patent Document 4. In the case of a route search in an underground shopping center or the building, information on the floor (floor) is required in addition to the latitude and longitude as the position information of the departure place and the target place that are the basis of the route search.

  This position information may basically be manually input from the navigation device 30 by the user, but the navigation device obtains the position information of the departure place from the position information transmission unit 100 and transmits it to the route search server. Also good. Then, the route search server embeds the guide route data in map data (route data for each floor from the floor of the departure location to the floor of the destination location) and transmits it to the navigation device 30, and the navigation device 30 sends this to the display unit. You can walk while displaying the route. In this case, the display needs to take a display form in which the route data of each floor can be seen through.

  On the other hand, in the display mode in which the route data of a plurality of floors is seen through, it is difficult for the user to visually recognize the guide route. Therefore, it is preferable to display only the route data and the guide route data of the floor on which the navigation device is moving. . This display form is the same as the display form of a normal navigation device, and it is easy for the user to visually recognize the guide route. For this purpose, if it is detected that the navigation device has reached the route moving vertically in the floor and then the next floor can be detected, only the route data and guidance route data of the floor on which the navigation device has moved can be detected. Can be displayed. Therefore, the position information transmission unit 100 is installed at the start and end points of routes such as stairs, elevators, and escalators that move vertically in the floor, and the navigation device searches for the position information received from the position information transmission unit 100. If it is sent to the server, it can be seen that the navigation device 30 has moved the route connecting the floors, and the route search server can send the required floor route data and route guidance data to the navigation device 30.

  FIG. 14 shows an example in which the position information transmission unit 100 according to the present invention is installed at each node (route origin / endpoint, intersection) n100 to n312 of each floor 1F to B2 shown in FIG. It is. The interval between the nodes n100 to n312 needs to be within a range (communication area) in which the transmission radio waves of the position information transmission unit 100 do not interfere with each other as described above. When the navigation device enters the communication area of the position information transmission unit 100 installed in a specific node, for example, n100, the position information (latitude, longitude, floor) is transmitted from the position information transmission unit 100 to the navigation device, and navigation is performed. The apparatus can determine (position) the current position from the position information.

  FIG. 15 is a diagram illustrating a configuration of links (routes) L1 to L29 that connect nodes n100 to n312 (see FIG. 14) where the position information transmission units 100 arranged on the floors 1F to B2 are installed. In FIG. 15, a link L6 from the node n110 to the node n211 is a route that moves from the floor 1F to the floor B1, for example, a staircase. Therefore, when the navigation device 30 is in the communication area of the location information transmission unit 100 installed at the node n110, the navigation device 30 receives the location information from the location information transmission unit 100 and obtains the latitude, longitude, and floor information. Obtainable. When the navigation device 30 reaches the link (route) L6, that is, the area of the position information transmission unit 100 installed at the node n211 by going down the stairs, position information is obtained from the position information transmission unit 100, and the latitude, longitude, and floor information are obtained. Can be obtained. As a result, the navigation device 30 can receive the route data and guidance route data of the floor reached from the route search server and display the route guidance map of the floor.

JP 2002-109679 A (FIGS. 4, 6, and 7) JP 2003-344093 A (FIGS. 16 to 23) Japanese Patent Laying-Open No. 2003-240591 (FIG. 2) JP 2001-165681 A (FIG. 1, paragraphs [0003] to [0010]) JP-A-8-278137 Report entitled “Pedestrian ITS (Intelligent Transport System) and high-precision positioning technology”, March 2002, Ministry of Land, Infrastructure, Transport and Tourism

  However, in the above-mentioned prior application, at the moment when the navigation device 30 enters a radio wave arrival range (communication area) of the position information transmission unit 100, the navigation device 30 seems to have reached the center position of the communication area. The position information is recognized within. This is because the position information stored in the position information transmission unit 100 is the latitude and longitude of the position where the position information transmission unit 100 is installed (position at the center of the radio wave reachable range), This is because it is not a position. That is, there is a difference between the position information acquired at the moment when the navigation device 30 enters the communication area and the position where the navigation device 30 actually exists by the communication distance of the position information transmission unit 100.

  FIG. 10 is a diagram illustrating the relationship between the position information transmission unit 100, the communication areas 100A to 100C, and the navigation device 30. As shown in FIG. 10, when the navigation apparatus enters the communication area 100A and receives position information from the position information transmission unit 100, the navigation apparatus 30 is at a position on the dotted line indicating the boundary of the communication area 100A. Nevertheless, it is recognized as being in the center position of the communication area 100A. Therefore, when the current position is displayed on the display screen of the display unit 38 of the navigation device 30, the current position recognized by the navigation device 30 is intermittently changed every time the communication area of the position information transmission unit 100 is switched. Thus, there is a problem in that the current position (own position) displayed on the screen of the navigation device 30 is intermittently changed and is observed as an unnatural movement by the user.

  The inventor of the present application has conducted various studies to solve the above-described problems, and as a result, the navigation device 30 enters the communication area of a specific position information transmission unit and starts receiving position information from the position information transmission unit. Note that the position of the actual navigation device can be calculated if the current position is calculated from the position information obtained from the position information transmission unit by a distance corresponding to the radius of the communication area. The invention has been completed. This relationship is the same when the navigation device leaves the communication area of a specific position information transmission unit. In this case, when position information cannot be received from the position information transmission unit, a position that has passed a distance corresponding to the radius of the communication area may be calculated as the current position from the position information obtained from the position information transmission unit.

  That is, the present invention has an object to solve the above-described problems, and a navigation apparatus that can obtain more accurate position information in a navigation apparatus that acquires a current position based on position information from a position information transmission unit. It is another object of the present invention to provide a position calculation method.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
A position information acquisition unit that acquires the position information from a position information transmission unit that transmits position information including the latitude and longitude of the installation position based on the short-range wireless communication standard, a position calculation unit, a display unit, and an orientation detection unit And a navigation device comprising:
The azimuth detecting unit detects the azimuth facing the navigation device,
The position calculation unit
When the location information acquisition unit receives new location information transmitted by the location information transmission unit from a new location information transmission unit,
Based on the new position information acquired by the position information acquisition unit, a circle that is a communication distance away from the installation position of the position information transmission unit and that has a radius of the communication distance of the new position information transmission unit Of the intersections between the link and the link, the intersection that matches the direction detected by the direction detection unit is calculated as the current position of the navigation device,
When the position information acquisition unit can no longer receive the position information from the position information transmission unit received so far,
Based on the position information from the position information transmission unit that has been received so far, it is a position that is a communication distance away from the installation position of the position information transmission unit, and the communication of the position information transmission unit that has been received so far Of the intersections between the circle having the radius of the distance and the link, the intersection that matches the direction detected by the direction detection unit is calculated as the current position of the navigation device.

  The invention according to claim 2 of the present application is the invention according to claim 1, wherein a plurality of the position information transmission units are continuously installed along the passage inside the structure, and the latitude of each installation position, The position information transmission unit transmits position information including longitude, and the navigation device is a pedestrian navigation device.

Further, in the invention according to claim 3 of the present application, in the invention according to claim 1 or claim 2, the position information acquisition unit obtains new position information transmitted from the new position information transmission unit by the position information transmission unit. When received, the navigation device stores the azimuth based on the direction of the ongoing link and the azimuth deviation detected by the azimuth detector,
When the position information acquisition unit cannot receive the position information from the position information transmission unit that has been received so far, the direction detected by the direction detection unit is corrected by the deviation and the navigation device is in progress The azimuth | direction of is calculated.

  The invention according to claim 4 of the present application is the invention according to claim 1 or 2, wherein the communication distance is a predetermined distance based on a communication standard in the position information transmission unit. .

  The invention according to claim 5 of the present application is the invention according to claim 1 or 2, wherein the communication distance is included in the position information transmitted by the position information transmission unit, and the navigation device includes the position information. It is characterized by receiving together.

The invention according to claim 6 of the present application is
A position information acquisition unit that acquires the position information from a position information transmission unit that transmits position information including the latitude and longitude of the installation position based on the short-range wireless communication standard, a position calculation unit, a display unit, and an orientation detection unit A position calculation method in a navigation device comprising:
The azimuth detecting unit detects the azimuth facing the navigation device,
The position calculation unit
When the location information acquisition unit receives new location information transmitted by the location information transmission unit from a new location information transmission unit,
Based on the new position information acquired by the position information acquisition unit, a circle that is a communication distance away from the installation position of the position information transmission unit and that has a radius of the communication distance of the new position information transmission unit Calculating the intersection that matches the orientation detected by the orientation detection unit as the current position of the navigation device,
When the position information acquisition unit can no longer receive the position information from the position information transmission unit received so far,
Based on the position information from the position information transmission unit that has been received so far, it is a position that is a communication distance away from the installation position of the position information transmission unit, and the communication of the position information transmission unit that has been received so far A step of calculating, as a current position of the navigation device, an intersection point that coincides with an orientation detected by the orientation detection unit among the intersection points of a circle having a radius of a distance and the link. .

The invention according to claim 7 of the present application is the invention according to claim 6, wherein the position information acquisition unit receives new position information transmitted by the position information transmission unit from a new position information transmission unit. In addition, the step of storing the azimuth based on the direction of the link the navigation device is in progress and the deviation of the azimuth detected by the azimuth detector
When the position information acquisition unit cannot receive the position information from the position information transmission unit that has been received so far, the direction detected by the direction detection unit is corrected by the deviation and the navigation device is in progress And a step of calculating the azimuth.

  In the first and second aspects of the invention, when the location information acquisition unit receives new location information from the new location information transmission unit, the location information transmission unit transmits based on the near field communication standard. The position calculation unit calculates, as the current position of the navigation device, a position that is a communication distance before the installation position of the position information transmission unit based on the new position information acquired by the position information acquisition unit, When the acquisition unit cannot receive the position information from the position information transmission unit that has been received so far, the position calculation unit, based on the position information from the position information transmission unit that has been received so far, A position ahead of the communication distance from the installation position of the position information transmission unit is calculated as the current position of the navigation device. Therefore, the position of the navigation device when the navigation device enters the communication area of the position information transmission unit can be accurately calculated, and the navigation device when the navigation device leaves the communication area of the position information transmission unit can be calculated. Since the position can be calculated accurately, the current position can be accurately displayed on the display unit of the navigation device.

In the invention according to claim 3, in the invention according to claim 1 or claim 2, when the position information acquisition unit receives new position information from the new position information transmission unit, the navigation device is in progress. The azimuth based on the direction of the link and the deviation of the azimuth detected by the azimuth detection unit are stored, and when the position information acquisition unit cannot receive the position information from the position information transmission unit received so far, The azimuth detected by the azimuth detecting unit is corrected by the deviation to calculate the azimuth in progress of the navigation device.
Since the position at the moment when the navigation device 30 enters the communication area is extremely pinpoint, an accurate deviation is obtained at that moment, and an accurate bearing can be corrected.

  In the invention according to claim 4, in the invention according to claim 1 or 2, the communication distance is a predetermined distance based on a communication standard in the position information transmission unit. Therefore, the navigation apparatus can easily calculate the position before or after the communication distance from the installation position of the position information transmission unit.

  In the invention according to claim 5, in the invention according to claim 1 or 2, the communication distance is included in the position information transmitted by the position information transmission unit, and the navigation device receives the position information together with the position information. Therefore, the navigation device can easily calculate the position before or after the communication distance from the installation position of the position information transmission unit.

  In the invention according to claim 6, when the position information acquisition unit receives new position information transmitted from the new position information transmission unit based on the short-range wireless communication standard, the position calculation unit Based on the new position information acquired by the position information acquisition unit, the position that is a communication distance from the installation position of the position information transmission unit is calculated as the current position of the navigation device, and the position information acquisition unit When the position information from the position information transmission unit that has been received cannot be received, the position calculation unit, based on the position information from the position information transmission unit that has been received so far, A position ahead of the communication distance from the installation position is calculated as the current position of the navigation device. Therefore, the position of the navigation device when the navigation device enters the communication area of the position information transmission unit can be accurately calculated, and the navigation device when the navigation device leaves the communication area of the position information transmission unit can be calculated. Since the position can be calculated accurately, the current position can be accurately displayed on the display unit of the navigation device.

In the invention according to claim 7, in the invention according to claim 6, when the position information acquisition unit receives new position information from the new position information transmission unit, the navigation device moves in the direction of the ongoing link. When the position information acquisition unit can no longer receive the position information from the position information transmission unit received so far, the direction detection unit The detected azimuth is corrected by the deviation, and the azimuth in progress of the navigation device is calculated.
According to such a correction method, since the position at the moment when the navigation device 30 enters the communication area is extremely pinpoint, an accurate deviation is obtained at that moment, and an accurate bearing can be corrected. .

  Hereinafter, specific examples of the present invention will be described in detail with reference to examples and drawings. FIG. 1 is a block diagram showing a configuration of a navigation apparatus according to the present invention. FIG. 2 is a schematic diagram for explaining a communication area of the position information transmission unit. FIG. 3 is a plan view showing a state in which the navigation device moves in a plurality of communication areas in contact with each other. FIG. 4 is a plan view showing a state in which the navigation device moves in a plurality of communication areas that do not contact each other. FIG. 5 is a plan view showing a state in which communication areas that overlap each other and communication areas that do not contact each other are combined. FIG. 6 is a flowchart showing a procedure for calculating position information in the navigation device 30. FIG. 7 is a diagram showing a state in which the navigation device moves in each communication area. FIG. 7A shows the movement state based on the current position calculation of the prior application with the center of the communication area as the current position and the present invention. FIG. 7B is a diagram showing a moving state based on the current position calculation, and FIG. 7B is a diagram showing an example in which the current position calculation method according to the present invention is applied to route matching processing. FIG. 8 is a diagram for explaining a communication area and a point for calculating the current position of the navigation device when the traveling direction of the navigation device is detected, and FIG. 8A shows a case where the navigation device enters the crossroads. FIG. 8B is a diagram showing a case where the navigation device escapes from the cross road, and FIG. 8C is a diagram showing a case of five differences. FIG. 9 is a schematic diagram for explaining a case where the present invention is applied to an intersection or the like where the GPS processing unit can perform positioning.

  As shown in FIG. 1 according to the present invention, a navigation device 30 is connected to a route search server 20 via a network 12 to constitute a navigation system 10. The route search server 20 includes a main control unit 21, a transmission / reception unit 23, a route search unit 25, a map database (DB) 27, and a guidance data creation unit 29. The main control unit 31 is configured around a microprocessor, and includes storage means such as a RAM and a ROM, as in a general computer device, and controls each part by a program stored in these storage means.

  The transmission / reception unit 23 receives data and a service request from the navigation device 30 and transmits (distributes) data required for the navigation device 30 and data necessary for the service. The map data DB (map data database) 27 is a database in which map information for distribution and display to the navigation device 30 and map data (node data, link data, cost data) for route search are accumulated. The search unit 25 searches the shortest guide route from the departure point to the destination with reference to the map data DB 27 in accordance with the route search requirement sent from the navigation device 30. As a search method, the Dijkstra method disclosed in Patent Document 4 described above can be used. The guide data creation unit 29 sets guide points such as branch nodes (intersections, etc.) guide points and voice guidance (guide) patterns at the guide points based on the optimum guide route data searched by the route search unit 25. Create

  On the other hand, the navigation device 30 includes a main control unit 31, a GPS processing unit 32, a transmission / reception unit 33, a position information acquisition unit 34, a position calculation unit 35, an orientation calculation unit 36, a route search request unit 37, a display unit 38, and an operation unit 39. It consists of and. The navigation device 30 performs a desired input and operation instruction from the operation unit 39, and displays a map and a guidance route distributed from the route search server 20 on the display unit 38. The main control unit 31 is configured around a microprocessor, and includes storage means such as a RAM and a ROM, as in a general computer device, and controls each part by a program stored in these storage means.

  The route search request unit 37 sends route search requirements such as a departure point, a destination, and a moving means to the route search server 20 and requests a route search. In general, the starting point and destination are indicated by latitude and longitude, but an address or telephone number is input and converted into latitude and longitude information in the database of the route search server 20 or the navigation device 30 For example, a point is specified on the displayed map and converted into latitude and longitude information. When searching for routes in an underground shopping center or a building, information on a departure place and a destination requires “floor” information in addition to latitude and longitude. The moving means is, for example, walking, a car, or a combination of walking and transportation. The information on the “floor” does not need to be input from the operation unit 39. For example, the number of the entrance, the name of the target store, a method of pointing and specifying on the map displayed on the navigation device 30, etc. Available. Of course, as the departure point information, the position information received by the position information acquisition 34 from the position information transmission unit 100 described later and calculated by the position information calculation unit 35 based on the position information can be used.

  The position information acquisition unit 34 receives position information from the position information transmission unit 100. The position information transmission unit 100 according to the present invention is the “latitude” of the position where the position information transmission unit 100 is installed as position information. ”,“ Longitude ”, and“ floor ”information as well as“ communication distance ”(radiation range) information of the position information transmission unit 100 are stored, and these information are stored in the navigation device 30 that has entered the communication area. Send. In FIG. 9, when the navigation apparatus 30 enters the communication area 100A of the position transmission unit 100 and the position information acquisition unit 34 starts to receive this information, the navigation apparatus 30 is positioned at the periphery (dotted line) of the communication area A. is there. Here, the position information transmission unit 100 is installed at the center of the communication area 100A, and the position information received by the position information acquisition unit 34 from the position information transmission unit 100 is information such as the latitude and longitude of the center position of the communication area 100A. is there.

  Therefore, for example, when the navigation device 30 enters a certain communication area (the moment the position information is received from the position information transmission unit that enters the communication area and is installed in the communication area), the position calculation unit 35 uses the position information transmission unit. By calculating the latitude and longitude of the position just before the communication distance of the position information transmission unit 100 from the position information (latitude and longitude) received from 100, the correct position of the navigation device 30 can be determined. Similarly, when the navigation device 30 leaves a certain communication area (the moment when the position information is no longer received from the position information transmitting unit installed in the communication area after leaving the communication area), the position calculation unit 35 transmits the position information. By calculating the latitude and longitude of the position that has passed through the communication distance of the position information transmission unit 100 from the position information (latitude and longitude) received from the unit 100, the correct position of the navigation device 30 can be determined.

  Here, the communication distance when the position information transmission unit 100 is installed on the ceiling of a building such as an underground shopping mall will be described with reference to FIG. When the position information transmission unit 100 is configured by a communication module that is compatible with a communication method using Bluetooth (registered trademark), a dashed circle 212 is a piconet (communication area) in Bluetooth (registered trademark). In plan view, it is usually a circle with a radius of about 10 m. At the moment when the navigation device 30 enters the communication area, the navigation device 30 receives position information via Bluetooth (registered trademark). The position information is the installation position 211 of the position information transmission unit 100, which is the center of a broken-line circle.

  When the position information transmission unit 100 is installed on the ceiling, the communication area is a hemispherical area as shown in FIG. Considering these, it may be handled as a communication distance of about 8 to 5 m. That is, the position information transmission unit 100 transmits information on the communication distance (for example, 8 m) together with the latitude and longitude information to the navigation device 30, and the navigation device 30 uses the position calculation unit 35 as described above. By calculating the latitude and longitude of the position just before the communication distance from the latitude and longitude that are the installation positions of the information transmission unit, the position of the navigation device 30 at the time of entering the communication area can be correctly calculated.

  When the navigation device 30 leaves the communication area, the calculation reverse to that in the above approach is performed. That is, when the navigation device 30 leaves the communication area 100A of FIG. 10 and the position information that has been received cannot be received, the communication distance (latitude, longitude) from the position (latitude, longitude) of the position information transmission unit 100 is reached. Similar to the above, it is only necessary to calculate the latitude and longitude of the previous position (position where the navigation device 30 has passed before it can no longer receive position information) by a distance of 8 m, for example. Since the position information (latitude, longitude, etc.) to the position information transmission unit 100 can be written by a writing device such as a personal computer at the installation location as described above, the communication distance information described above is actually obtained from the position information transmission unit 100. It is also possible to measure the reach of the radio wave at a place installed in and to write the actual measurement value.

  FIG. 3 is a diagram illustrating a state in which the position calculation unit 35 has calculated the current position of the navigation device 30 and moved as described above. According to the guidance route distributed by the route search server 20, first, at the moment when the navigation device 30 enters the communication area 100A, the position calculation unit 35 determines the position of the peripheral edge (on the circumference of the dotted line) of the communication area 100A. The position is calculated as the position of the navigation device 30, and the position is displayed like the display screen of the display unit 38. Next, the navigation device 30 turns right in the direction B in the figure according to the guidance route, exits the communication area 100A, and then enters the adjacent communication area 100C. The position (on the circumference of the dotted line) is calculated as the position of the navigation device 30, and the position is displayed like the display screen of the display unit 38. At this time, the map displayed on the display unit 38 of the navigation device 30 is routed up (scrolled up), and an adjacent map is displayed.

  FIG. 4 is a diagram illustrating a case where the current position is calculated even when the navigation device 30 leaves (exits) from the communication area. In FIG. 3, the communication areas 100A to 100D are in contact with each other, but in FIG. 4, the communication areas 100A to 100D are not in contact with each other, and there are areas where the radio waves of the position information transmission unit 100 do not reach between the communication areas. The difference is that the information transmission unit 100 is installed.

  In FIG. 4, according to the guidance route distributed by the route search server 20, first, at the moment when the navigation device 30 enters the communication area 100A, the position calculation unit 35 causes the peripheral portion of the communication area 100A (on the circumference of the dotted line). Is calculated as the position of the navigation device 30, and the position of the navigation device 30 is displayed like the display screen of the display unit 38. Next, the position information that the navigation device 30 has received in the communication area 100A at the moment when the navigation device 30 turns right in the direction B in the figure and exits the communication area 100A according to the guidance route (position B in FIG. 4). Cannot be received. Therefore, the position calculation unit 35 uses the position information (latitude, longitude, etc.) of the position information transmission unit 100 that has been received so far to determine the position (the distance that has already been moved) ahead of the communication distance by the current position of the navigation device 30. Calculate as position.

  Thereby, the position of the point where the navigation device 30 leaves the communication area 100A is calculated, and displayed on the display unit 38 so that the navigation device 30 is positioned at the point. Next, at the moment when the navigation device 30 enters the new communication area 100C, the same position calculation as described above is performed, and the current position of the navigation device 30 is calculated at the periphery of the communication area 100C. Then, the current position of the navigation device 30 is displayed on the display unit 38. Then, at the moment when the navigation device 30 leaves the communication area 100C, the position calculation unit 35 is ahead of the communication distance based on the position information (latitude, longitude, etc.) of the position information transmission unit 100 received so far. The position (the distance that has already been moved) is calculated as the current position.

  As described above, if the communication areas of the position information transmission units are installed so as not to overlap, the position information can be calculated at two places when the navigation device 30 enters and exits one communication area. In the above-mentioned prior application, only position information of one central position was obtained in one communication area. However, it is possible to obtain and obtain position information of two places for one communication area as shown in FIG. By doing so, the moving state of the navigation device 30 can be displayed in a natural manner, and the moment when the map display on the display unit 38 scrolls indicates the correct current position of the navigation device 30, which is very much for the user. An easy-to-understand display can be provided. Therefore, each position information transmission unit 100 has a communication area that overlaps each other as shown in FIG. 5, and there is no portion where the communication areas touch each other at intervals or overlap. It can be installed freely.

  Next, the position calculation procedure of the navigation device 30 will be described. FIG. 6 is a flowchart showing a procedure of position information calculation in the navigation device 30 described in FIG. 3 or FIG. In this flowchart, the reception flag is a flag that is set when the navigation apparatus 30 can normally receive the position information of the position information transmission unit 100, and is reset when the position information cannot be received. The process from the start to the end is a procedure for position confirmation (position information acquisition, position calculation) that is repeatedly called from the navigation device 30, and the basic process of communication and navigation is processed in the lower layer. And

  In the navigation device 30, first, the position information acquisition unit 34 communicates with the position information transmission unit 100 in step S101, and receives position information in step S102. If the position information has been received, the position information acquisition unit 34 checks the state of the reception flag in step S103. If the state of the reception flag is reset, it means that new position information has been received, and thus the process proceeds to step S104 and the position calculation unit 35 calculates the current position of the navigation device 30 when entering the communication area described above. To do. That is, the fact that the reception flag is in the reset state indicates the moment when the navigation device 30 enters the communication area of the new position information transmission unit 100, and therefore the position information received from the new position information transmission unit 100. The current position is obtained by calculating the latitude and longitude of the position just before the communication distance from (latitude, longitude, communication distance, etc.) (step S104). In step S105, the reception flag is set and the process is terminated.

  If the reception flag is set in step S103, the process proceeds to step S106, and the position information acquisition unit 34 confirms whether the received position information is new position information. This is because the navigation device 30 may be in the communication area of the new position information transmission unit 100 even if the position information acquisition unit 34 continuously receives the position information. For example, as shown in FIG. 5, the communication areas of the position information transmission unit 100 may be installed so as to overlap. If it is determined in step S106 that the received position information is a new communication area, the process proceeds to step S104, where the position calculation unit 35 calculates the position of the navigation device 30 as described above, and resets the reception flag in step S105. End the process. If it is not a new communication area, the process ends.

  On the other hand, if position information has not been received in step S102, the process proceeds to step S107 to check the state of the reception flag. If the state of the reception flag is set, it indicates that the navigation device 30 has just left the communication area where it has been located so far, so that the process proceeds to step S108 and the communication area described above by the position calculation unit 35. The current position of the navigation device 30 when leaving is calculated. That is, the fact that the reception flag is in the set state indicates that the navigation device 30 has just exited the communication area of the position information transmission unit 100 that has previously received the position information. From the position information (latitude, longitude, communication distance, etc.) received from the unit 100, the current position is obtained by calculating the latitude and longitude of the position (position on the guide route) ahead by the communication distance (step S108). It is. In step S109, the reception flag is set and the process is terminated.

  If the reception flag is reset in step S107, the position information from the position information transmission unit 100 has not been received (step S102) and has not been continuously received. 30 ends the processing without doing anything.

  As in this procedure, the navigation device 30 does not measure the installation position of the position information transmission unit 100 as the current position, but the navigation device 30 is currently located in two locations: the position where the navigation device 30 enters the communication area and the position where it exits the communication area. If the position is displayed as the position, as shown in FIG. 7A, the moving path of the navigation device 30 does not become a meandering path connecting the installation of the position information transmitting unit 100, but the entry position and the leaving position to each communication area. Can be displayed as a straight line connecting positions. In addition, as shown in FIG. 7B, even when route matching is performed on the guide route, the position information that can be acquired only at one location of the position information transmission unit 100 in the previous application is the entry position of the communication area, the departure from the communication area. Position information can be calculated at two positions. Therefore, the moving route displayed on the navigation device 30 can be displayed in a state in accordance with the actual moving route. In particular, in a place only for passing through, such as a communication passage, even if the position information providing device is intentionally wide, guidance can be provided with double the resolution according to the present invention, so the number of installed equipment can be reduced.

  The above description relates to a mode in which data on the guidance route for the navigation device 30 is provided from the route search server 20, and the navigation device 30 performs route matching processing for matching the current position on the guidance route. Even if there is no guide route data, the current position can be specified. For that purpose, it is used for so-called heading-up processing, which is displayed with the north of the map displayed on the display unit on the mobile phone up or displayed according to the direction that the user is observing. Use an orientation detection means such as an electronic compass. For this reason, the navigation device 30 is provided with an orientation detection unit 36 (see FIG. 1). In FIG. 1, the azimuth detecting unit 36 includes azimuth detecting means such as the electronic compass described above.

  When the navigation device 30 is a mobile phone or the like, the navigation device 30 detects the moving direction by using a method in which the upper direction of the display screen is the moving direction, an acceleration sensor, and the attitude and moving speed of the navigation device 30. There is a method of calculating the traveling direction of the apparatus 30 in any posture. For example, it is possible to detect the azimuth of the navigation device 30 using the technique disclosed in Patent Document 5 and further integrate the detection value of the acceleration sensor to obtain the traveling direction.

  When the traveling direction of the navigation device 30 is known in this way, as shown in FIG. 8A, from which direction the navigation device 30 enters the communication area 100A, and as shown in FIG. 8B. The navigation device 30 can instantaneously determine in which direction the navigation device 30 has exited the communication area 100A, so that it can be determined from which link the navigation device 30 has entered the communication area and from which link has exited the communication area. Become. Therefore, a point on the link that is separated from the communication area by the communication distance (the communication distance of the position information transmission unit in the communication area) is the current position of the navigation device 30. Further, even if the link is not a crossroad as shown in FIGS. 8A and 8B, it can be seen in which direction the navigation device 30 has entered or left the communication area. As shown in c), the current position can be correctly calculated from the traveling direction of the navigation device 30 even if there are five differences.

  In fact, it is known that geomagnetism has regional deviations and local magnetic anomalies. In particular, in the vicinity of subway stations, the direction is measured with errors due to the effects of underground steel structure, rail iron, train current, and the like. The difference between the direction of the link when entering the communication area and the direction observed by the sensor is the overall deviation of the point. Therefore, if the deviation is temporarily stored and used as a correction value for the next azimuth measurement, a path with a small azimuth difference of the exit link as shown in FIG.

  Thus, at the moment when the navigation device 30 enters the communication area, the difference between the direction based on the link (traveling direction) on the map data and the output of the magnetic sensor or the like direction detection unit 36 is observed as a deviation. The rotation amount of the map display displayed on the display unit 38 can be corrected using this. According to the above correction method, since the position at the moment when the navigation device 30 enters the communication area is extremely pinpoint, an accurate deviation is obtained at that moment, and an accurate azimuth correction can be performed.

  The embodiment of the present invention described above is a case where the GPS processing unit 32 cannot perform positioning as in an underground shopping center or a building. However, if the position information transmission unit is installed in the present invention, the GPS processing unit is provided. The present invention can also be applied in an environment where positioning by 32 is possible. That is, as shown in FIG. 9, the position information transmission unit 100 is arranged at the four corners of the intersection X so that the communication areas are 100A to 100D, and the navigation device 30 enters the communication area as described above. If the position that has left the communication area is accurately calculated, it can be easily determined how the navigation device 30 is moving at the intersection, and the route display is also easy for the user to understand. It can be displayed as a natural moving state.

  In the embodiment of the present invention described above, the communication type navigation system in which the navigation device 30 communicates with the route search server 20 via the network has been described as an example. However, the navigation device 30 is not limited to this. Even a portable navigation device having the function of the route search server 20 can be applied.

It is a block diagram which shows the structure of the navigation system with which the navigation apparatus concerning this invention is applied. It is a schematic diagram for demonstrating the communication area of a positional infomation transmission unit. It is a top view which shows the state which a navigation apparatus moves in the some communication area which mutually touches. It is a top view which shows the state which a navigation apparatus moves in the some communication area which does not contact | connect mutually. It is a top view which shows the state with which the communication area which mutually overlaps and the communication area which does not mutually contact are combined. 4 is a flowchart showing a procedure for calculating position information in the navigation device 30. FIG. 7A is a diagram showing a state in which the navigation device moves in each communication area. FIG. 7A shows a movement state based on the current position calculation of the prior application with the center of the communication area as the current position and the current position calculation according to the present invention. FIG. 7B is a diagram showing an example in which the current position calculation method according to the present invention is applied to route matching processing. FIG. 8 is a diagram for explaining a communication area and a point for calculating a current position of the navigation device when detecting a traveling direction of the navigation device, and FIG. 8A is a diagram illustrating a case where the navigation device enters the crossroads. (B) is a figure which shows the case where a navigation apparatus escapes from a crossroad, FIG.8 (c) is a figure which shows the case of 5 difference roads. It is a schematic diagram for demonstrating the case where this invention is applied to the intersection etc. which a GPS process part can measure. It is a schematic diagram for demonstrating the problem in a prior application. It is a figure which shows the structure of the positional information transmission unit of a prior application. It is a top view which shows the state which has arrange | positioned the positional information transmission unit of a prior application continuously. It is a figure which shows floor layouts, such as an underground shopping mall, where the positional information transmission unit of a prior application is installed. It is a figure which shows the state which installed the positional infomation transmission unit in the node in FIG. It is a figure which shows the structure of the link in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Navigation system 12 ... Network 20 ... Route search server 21 ... Main control unit 23 ... Transmission / reception unit 25 ... Route search unit 27 ... Map Data DB (map data database)
29... Guidance data creation unit 30... Navigation device 31... Main control unit 32... GPS processing unit 33. ... Position calculation part 36 ... Direction detection part 37 ... Route search request part 38 ... Display part 39 ... Operation part

Claims (7)

A position information acquisition unit that acquires the position information from a position information transmission unit that transmits position information including the latitude and longitude of the installation position based on the short-range wireless communication standard, a position calculation unit, a display unit, and an orientation detection unit And a navigation device comprising:
The azimuth detecting unit detects the azimuth facing the navigation device,
The position calculation unit
When the location information acquisition unit receives new location information transmitted by the location information transmission unit from a new location information transmission unit,
Based on the new position information acquired by the position information acquisition unit, a circle that is a communication distance away from the installation position of the position information transmission unit and that has a radius of the communication distance of the new position information transmission unit Of the intersections between the link and the link, the intersection that matches the direction detected by the direction detection unit is calculated as the current position of the navigation device,
When the position information acquisition unit can no longer receive the position information from the position information transmission unit received so far,
Based on the position information from the position information transmission unit that has been received so far, it is a position that is a communication distance away from the installation position of the position information transmission unit, and the communication of the position information transmission unit that has been received so far A navigation device characterized in that, among intersection points between a circle having a radius as a distance and a link, an intersection point that matches the direction detected by the direction detection unit is calculated as the current position of the navigation device.   The position information transmission unit is a position information transmission unit that is continuously installed along the path inside the structure and transmits position information including the latitude and longitude of each installation position, and the navigation device is a walking The navigation device according to claim 1, wherein the navigation device is a navigation device for a person. When the position information acquisition unit receives new position information transmitted from the new position information transmission unit by the position information transmission unit, the direction detection unit detects the azimuth based on the direction of the link that the navigation device is in progress. Memorize the deviation of
When the position information acquisition unit cannot receive the position information from the position information transmission unit that has been received so far, the direction detected by the direction detection unit is corrected by the deviation and the navigation device is in progress The navigation device according to claim 1, wherein the azimuth is calculated.   The navigation apparatus according to claim 1, wherein the communication distance is a predetermined distance based on a communication standard in the position information transmission unit.   The navigation apparatus according to claim 1 or 2, wherein the communication distance is included in position information transmitted by the position information transmission unit, and the navigation apparatus receives the position information together with the position information. A position information acquisition unit that acquires the position information from a position information transmission unit that transmits position information including the latitude and longitude of the installation position based on the short-range wireless communication standard, a position calculation unit, a display unit, and an orientation detection unit A position calculation method in a navigation device comprising:
The azimuth detecting unit detects the azimuth facing the navigation device,
The position calculation unit
When the location information acquisition unit receives new location information transmitted by the location information transmission unit from a new location information transmission unit,
Based on the new position information acquired by the position information acquisition unit, a circle that is a communication distance away from the installation position of the position information transmission unit and that has a radius of the communication distance of the new position information transmission unit Calculating the intersection that matches the orientation detected by the orientation detection unit as the current position of the navigation device,
When the position information acquisition unit can no longer receive the position information from the position information transmission unit received so far,
Based on the position information from the position information transmission unit that has been received so far, it is a position that is a communication distance away from the installation position of the position information transmission unit, and the communication of the position information transmission unit that has been received so far A step of calculating, as a current position of the navigation device, an intersection point that coincides with an orientation detected by the orientation detection unit among the intersection points of a circle having a radius of a distance and the link. . When the position information acquisition unit receives new position information transmitted from the new position information transmission unit from the new position information transmission unit, the direction based on the direction of the link that the navigation device is in progress, and the direction detection unit Storing the detected deviation of the bearing;
When the position information acquisition unit cannot receive the position information from the position information transmission unit that has been received so far, the direction detected by the direction detection unit is corrected by the deviation and the navigation device is in progress The position calculating method according to claim 6, further comprising a step of calculating the azimuth.

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