JP2008286676A - Navigation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation device using map information downloaded through a network, capable of further efficiently acquiring information. <P>SOLUTION: In the navigation device 100, a specification means (specification program 64b, etc.) specifies a traveling direction, a map information acquisition means (map information acquisition program 64c, etc.) acquires map information divided in predetermined area units through the network, and a storage control means (storage control program 64d, etc.) stores the map information acquired by the map information acquisition means (map information acquisition program 64c, etc.) in a map information storage part 632b. The map information acquisition means (map information acquisition program 64c, etc.) acquires map information of a near area which is an area adjacent to an area where a vehicle is traveling, and present in the traveling direction specified by the specification means (specification program 64b, etc.). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a navigation device.

2. Description of the Related Art In recent years, navigation devices that measure the current position using GPS (Global Positioning System) or the like and display the measured current position on a display screen together with map information have been put into practical use.

In such a navigation apparatus, in addition to a form for displaying a map based on map information held in advance by the navigation apparatus itself, a form for displaying a map based on map information downloaded via a network is known. ing.
For example, Patent Document 1 discloses a technique for accessing a data providing center and downloading a desired parcel (map information) in a car navigation device having a communication function. Similarly, in Patent Document 2, by using the map data downloaded in advance and stored in the storage unit, a map of the current position is immediately displayed without providing a storage means for a large amount of map data. A map display system is disclosed that can be performed.
Furthermore, in Patent Document 3, in a map display system that sequentially downloads and displays a plurality of maps having different scales as the vehicle travels, a map of different scales is displayed when the map can be downloaded. In addition, a map display system that determines whether to execute or not to download based on user selection information has been proposed, thereby preventing unnecessary billing caused by downloading a map not desired by the user. it can.
Japanese Patent Laid-Open No. 2003-247843 JP 2005-98707 A JP 2004-354819 A

  However, in the techniques of Patent Document 1 and Patent Document 2 described above, since map information around the vehicle position is downloaded, there is a high possibility that map information that is not in the traveling direction of the vehicle is not used. There has been a problem of waste in terms of time and capacity for storing map information. Moreover, in the map display system of patent document 3, execution / non-execution of download had to be selected, and there existed a problem that operation for that was troublesome.

  The subject of this invention is providing the navigation apparatus which can acquire map information more efficiently in the navigation apparatus using the map information downloaded via the network.

In order to solve the above-mentioned problem, the invention according to claim 1 is a navigation device comprising a current position detecting means for detecting a current position.
A specifying means for specifying the traveling direction of the navigation device;
Map information acquisition means for acquiring map information partitioned into predetermined area units via a network;
Storage control means for storing the map information acquired by the map information acquisition means in a storage unit;
With
The map information acquisition means acquires the map information of an approach area that is an area adjacent to a traveling area and existing in the traveling direction specified by the specifying means.

  According to a second aspect of the present invention, in the navigation device according to the first aspect, the map information acquisition means is configured to detect the approach area when the distance from the current position to the approach area becomes a predetermined value or less. The map information is acquired.

According to a third aspect of the present invention, in the navigation device according to the first or second aspect, is an area where the map information is not stored in the storage unit within a predetermined first range from the current position. A determination means for determining whether or not,
The map information acquisition unit acquires the map information of the area when the determination unit determines that there is an area in which the map information is not stored within a predetermined first range from the current position. It is characterized by doing.

  Invention of Claim 4 is the navigation apparatus as described in any one of Claims 1-3. The present position detected by the said present position detection means among the said map information memorize | stored in the said memory | storage part. And deleting means for deleting map information at a position away from the second range by a predetermined second range or more.

The invention according to claim 5 is a navigation device comprising a current position detecting means for detecting a current position.
A specifying means for specifying the traveling direction of the navigation device;
Map information acquisition means for acquiring map information partitioned into predetermined area units via a network;
Storage control means for storing the map information acquired by the map information acquisition means in a storage unit;
Determining means for determining whether there is an area in which the map information is not stored in the storage unit within a predetermined first range from the current position;
A deletion unit that deletes map information at a position away from the current position detected by the current position detection unit by a predetermined second range or more among the map information stored in the storage unit;
With
The map information acquisition unit is configured to display the map information of an approach area that is adjacent to a traveling area and that exists in the traveling direction specified by the specifying unit, and the distance between the current position and the approach area is When it is acquired when the value is equal to or less than a predetermined value, and the determination means determines that an area in which the map information is not stored in the storage unit exists within a predetermined first range from the current position. The map information of the area is acquired.

According to the present invention, the specifying unit specifies the traveling direction of the navigation device, the map information acquiring unit acquires map information divided into predetermined area units via the network, and the storage control unit acquires map information. The map information acquired by the acquisition unit is stored in the storage unit, and the map information acquisition unit stores the map information of the approaching area that is adjacent to the traveling area and that exists in the travel direction specified by the specifying unit. To be acquired.
Therefore, in the navigation device using the map information downloaded via the network, only the map information of the adjacent area existing in the traveling direction is acquired, so that the map information can be acquired more efficiently.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, the overall configuration of the navigation device 100 of the present embodiment will be described with reference to FIG.
A navigation device 100 according to the present embodiment is a portable navigation device mounted on a vehicle as shown in FIG. 1, for example, and is connected to an information providing device 200 via a network N.

The information providing device 200 is a device that provides various information such as map information and route guidance to a terminal device such as the navigation device 100 connected to the network N, and includes a communication unit 200a, a map information DB 200b, and a user information DB 200c. Yes.
The communication unit 200a receives various requests such as a map information request signal from the navigation device 100 connected via the network N, and distributes various information such as map information to the navigation device 100 in response to the request.

  The map information DB 200b stores, for example, map information of different types and scales in a hierarchical structure. For example, when classifying according to the type of road to be recorded, a high-level map containing a high-speed automobile national road and a general national road is stored in the upper hierarchy, and a road displayed as a wide-area map in the middle hierarchy In addition to the map, prefectural roads and municipal roads are stored. In addition to the roads displayed in the middle map, a detailed map containing narrow streets is stored in the lower hierarchy. To do.

Furthermore, the map information stored in each hierarchy is a set of data in predetermined area units. Here, for example, area division is performed in units of prefectures (predetermined areas).
For example, the map information will be described with reference to the map information illustrated in FIG. The map information is divided into prefectures, and an area code is assigned to each divided area. As the area code, for example, a code having a hierarchical structure including a code for each region as an upper layer (for example, “6” for the Kinki region) and a code for each prefecture in the lower layer is used. For example, in the example of FIG. 3, the area code “6-3” is assigned to Osaka Prefecture, “6-4” is assigned to Nara Prefecture, and “6-5” is assigned to Wakayama Prefecture.
The area division is not limited to that performed in units of prefectures, and can be divided in arbitrary units. For example, it may be divided into smaller areas such as municipalities and administrative divisions. Moreover, you may perform the mesh division | segmentation which divides | segments the ground surface into mesh shape.

The map information for each area includes node information of nodes included in the area and link information of links. The node information defines the intersection of the link (intersection), the end point of the link (dead end), and the point at which the link attribute changes. For example, the node ID, the node coordinates, the node name, and the link connected to the node Link ID and the like. The link information defines the line segment connecting each node. For example, link ID, link distance, link start / end coordinates, road name, road type, width, number of lanes , Traffic regulation, etc.
Further, the map information includes facility information, store information, building information, address information, park information, railroad information, topographic information, etc. in addition to the node information / link information described above. Based on these data, the map information Information display, route search, and route guidance information are provided.

  The user information DB 200c stores, for example, information on terminals such as the navigation device 100 connected to the information providing device 200 via a network. Specifically, for example, the terminal ID of each terminal, the display size of the display unit 4, the resolution, and the like are associated and stored.

Next, the principal part structure of the navigation apparatus 100 of this embodiment is demonstrated, referring FIG.
For example, as shown in FIG. 2, the navigation device 100 includes a current position detection unit 1 as a current position detection unit, a direction detection unit 2 as a specification unit, a communication unit 3 as a map information acquisition unit, a display unit 4, and an input. It comprises the part 5, the control part 6, etc.

The current position detection unit 1 includes, for example, a GPS positioning unit that detects absolute coordinates of the navigation device 100, detects current position information of the navigation device 100 itself, and generates a current position detection signal based on the detected current position information. Output to the control unit 6.
Specifically, the GPS positioning unit receives, for example, radio waves from a plurality of (for example, at least three) artificial satellites whose positions are known by a GPS antenna (not shown), and receives the radio waves received from each artificial satellite. From the arrival time, the distance from each artificial satellite to the navigation device 100 is calculated, and the latitude / longitude data of the intersection of the distance from each artificial satellite is specified.

  The direction detection unit 2 includes, for example, an orientation sensor such as a gyro sensor that detects the angular velocity of the navigation device 100, a geomagnetic sensor that detects the absolute orientation of the navigation device 100 by measuring magnetism, and the like. The traveling direction is detected, and a traveling direction detection signal based on the detected traveling direction is output to the control unit 6.

  Further, a travel distance detection sensor that detects a travel distance by measuring a pulse corresponding to the travel may be provided, and the current position detection means may be configured by the travel distance detection sensor and the direction detection unit 2 described above.

  For example, the communication unit 3 is connected to the information providing apparatus 200 via a network, and transmits various requests such as a map information request signal to the information providing apparatus 200 via the network N. In response to this request, Various information such as map information transmitted from the information providing apparatus 200 is received.

  The display unit 4 includes a display such as an LCD (Liquid Crystal Display), for example, and displays map information and other various information on the display according to control from the control unit 6.

  The input unit 5 includes, for example, a character / number key, various function keys, a touch panel configured integrally with the display unit 4 and the like, and outputs a key press signal based on a key press by the user to the control unit 6. When a touch operation is performed by the user on the touch panel, the coordinates of the touch operation are calculated, and a press signal based on the calculated coordinates is output to the control unit 6.

  The control unit 6 includes a CPU (Central Processing Unit) 61, an RTC (Real Time Clock) 62, a memory unit 63, a ROM (Read Only Memory) 64, and the like.

  The CPU 61 executes various programs stored in the ROM 64 in accordance with input signals and the like input from each unit of the navigation device 100, and outputs an output signal to each unit based on the execution program. The overall control of 100 operations is controlled.

  The RTC 62 measures time data such as the current time and outputs the time data thus measured to the CPU 61.

  The memory unit 63 includes a work area 631 formed of a volatile memory such as a RAM (Random Access Memory), for example, and the processing results generated when various programs are executed by the CPU 61, input data, and the like The work area 631 is stored.

  The memory unit 63 includes a data area 632 made of a nonvolatile memory such as an EPROM (Erasable Programmable ROM). The data area 632 includes, for example, an area code storage unit 632a and a map information storage unit (storage unit) 632b.

The area code storage unit 632a stores an area code assigned to each piece of area map information constituting the map information.
FIG. 4 is a diagram illustrating the area code storage unit 632a. As shown in FIG. 4, the area code storage unit 632a allocates and stores an area code for each area divided into prefectures, and the local name, prefecture name, and location information in which the area exists. (Latitude range / longitude range) and area codes of adjacent areas are stored in association with each other.

  The map information storage unit 632b stores the map information acquired from the information providing apparatus 200 via the network N by executing a map information acquisition program 64c described later.

  The ROM 64 has, for example, a program storage area composed of a nonvolatile memory, and stores a current position detection program 64a, a specific program 64b, a map information acquisition program 64c, a storage control program 64d, a deletion program 64e, and the like.

The current position detection program 64a is a program for causing the CPU 61 to realize a function of detecting the current position P, for example.
Specifically, the CPU 61 causes the current position detection unit 1 configured by a GPS positioning unit or the like to acquire current position information of the navigation device 100 itself, and generates a current position detection signal output from the current position detection unit 1. Based on this, the coordinates (latitude / longitude) as the current position P of the navigation device 100 are specified. Further, map matching processing is performed based on the specified current position P, and the road where the vehicle on which the navigation device 100 is mounted is matched with matching data stored in a predetermined area such as the data area 632 ( (Not shown). In the map matching process, for example, a road that is a candidate for matching is determined according to the travel locus of the vehicle, a road having the highest correlation is identified from the candidates for matching, and pattern matching that matches the current position P on the road is performed. Use.
The CPU 61 functions as a current position detection unit together with the current position detection unit 1 by executing the current position detection program 64a.

The specifying program 64b is a program for causing the CPU 61 to realize a function of specifying the traveling direction of the navigation device 100, for example.
Specifically, the CPU 61 causes the direction detection unit 2 configured by a geomagnetic sensor, a direction sensor, and the like to detect the travel direction of the navigation device 100 and based on the travel direction detection signal output from the direction detection unit 2. The traveling direction of the navigation device 100 is specified.
The CPU 61 functions as a specifying unit together with the direction detection unit 2 by executing the specifying program 64b.

The map information acquisition program 64c is a program for causing the CPU 61 to realize a function of acquiring map information partitioned into predetermined area units via the network N, for example.
Specifically, in the execution of the map information acquisition program 64c, the CPU 61 is map information of an approaching area that is an area that is adjacent to the traveling area and that exists in the traveling direction specified by the execution of the specifying program 64b. Is acquired when the distance from the current position P to the approaching area is equal to or smaller than a predetermined value D. Further, the CPU 61 determines whether or not there is an area where no map information is stored in the map information storage unit 632b within a predetermined first range R1 from the current position P, and the predetermined first range R1 from the current position P. When it is determined that there is an area in which no map information is stored in the map information storage unit 632b within the range R1, the map information of the area is acquired.
The CPU 61 functions as a determination unit and a map information acquisition unit by executing the map information acquisition program 64c.

Here, first, the map information acquisition process of the approach area by the execution of the map information acquisition program 64c will be described with reference to FIGS.
The CPU 61 executes the above-described current position detection program 64a while specifying the coordinates (latitude / longitude) of the current position P of the navigation device 100 while the vehicle on which the navigation device 100 is mounted is running. 64b is executed, and the traveling direction of the navigation device 100 is specified. 5 to 11, the mark P indicates the current position P of the navigation device 100, and the arrow indicates the traveling direction of the navigation device 100.
When the CPU 61 specifies the coordinates as the current position P, the CPU 61 refers to the area code storage unit 632a based on the coordinates, determines the area where the current position is located, and determines the adjacent area adjacent to the current area. . In the example of FIG. 5, Osaka prefecture with area code “6-3” is determined as the current area, and Kyoto prefecture with area code “6-2”, Nara prefecture with “6-4”, and “6-5”. "Wakayama Prefecture" and "6-6" Hyogo Prefecture are determined to be adjacent areas.
And CPU61 specifies the adjacent area which exists in the direction specified as the running direction among adjacent areas, and makes this an approach area. In the example of FIG. 5, the Wakayama prefecture with the area code “6-6” is specified as the approaching area.

Next, the CPU 61 determines the distance from the current position P to the approaching area based on the position information in the area code storage unit 632a. Further, when the distance from the current position P to the approaching area (for example, Wakayama Prefecture) is determined, it is determined whether or not the distance is equal to or less than a predetermined value D (for example, 30 km). For example, in the example of FIG. 6, it is determined that the distance to the approaching area is not less than the predetermined value D.
Thereafter, when the vehicle continues to travel further and is positioned at P in FIG. 7, for example, it is determined that the distance to the approaching area is equal to or less than the predetermined value D. Then, the CPU 61 determines whether or not the map information of the approach area is stored in the map information storage unit 632b. If the map information of the approach area is not stored, the CPU 61 requests the map information of the approach area. The map information request signal to be transmitted is transmitted to the information providing apparatus 200 via the network N by the communication unit 3. The map information request signal includes an area code of an approaching area for which map information is desired to be acquired. Upon receiving the map information request signal, the information providing apparatus 200 receives a map based on the area code included in the map information request signal. The map information of the area to which the area code is assigned is read from the information DB 200b, and the read map information is transmitted to the navigation device 100 via the network N. At this time, the user information DB 200c is referred to, and the display size / resolution map information in the navigation device 100 is transmitted. In the navigation device 100, when map information is transmitted from the information providing device 200, the CPU 61 receives the map information by the communication unit 3.

Next, with reference to FIGS. 8 and 9, a map information acquisition process for an area existing within a predetermined first range R1 of the current position P by executing the map information acquisition program 64c will be described.
As described above, the CPU 61 executes the current position detection program 64a described above while the vehicle on which the navigation device 100 is mounted, and specifies the coordinates (latitude / longitude) of the current position P of the navigation device 100. At the same time, when the above-described specifying program 64b is executed to specify the traveling direction of the navigation device 100, it is determined whether or not there is an area other than the approaching area within the predetermined first range R1 from the current position P. Here, the predetermined first range R1 from the current position P is a half-circle region having a radius of 25 km centered on the current position P and extending in the traveling direction, and is a shaded portion in FIG. Note that the position P in FIG. 8 is assumed to be the same as the position P in FIG.
For example, in the example of FIG. 8, it is determined that there is no area other than the approaching area within the first range R1 from the current position P. After that, when the vehicle continues to travel and is positioned at P in FIG. 9, for example, an area other than the approach area (for example, area code “ 6-4 "(Nara Prefecture) is determined, and the area is specified as an area existing within the first range R1 from the current position P.

  When the CPU 61 determines that there is an area other than the approaching area within the first range R1 from the current position P, the CPU 61 determines whether or not the map information of the area is stored in the map information storage unit 632b. And when the map information of the said area is not memorize | stored, the map information request signal which requests | requires the map information of the said area is transmitted to the information provision apparatus 200 via the network N by the communication part 3. FIG. Then, the information providing apparatus 200 performs the above-described processing, reads map information from the map information DB 200b, and transmits the map information to the navigation apparatus 100 via the network N. In the navigation device 100, when map information is transmitted from the information providing device 200, the CPU 61 receives the map information in the communication unit 3.

The first range R1 from the current position P is not limited to the semicircular area illustrated in FIGS. 8 and 9, and may be a circular area such as 270 degrees and 360 degrees, or a rectangular area or other May be a polygonal region or the like.
In the above description, the distance of the first range R1 is configured to be shorter than the predetermined value D for acquiring the map information of the approach area. That is, at the time when the vehicle is located at P in FIGS. 7 and 8, only the map information of the approaching area existing in the traveling direction is acquired, and when the vehicle further travels and is located at P in FIG. The map information of the area that exists in the first range R1 that does not exist in the traveling direction is acquired. Accordingly, the map information of the approaching area that exists in the traveling direction and is more likely to travel is preferentially acquired, and the efficiency of acquiring the map information is further improved.

The storage control program 64d is, for example, a program for causing the CPU 61 to realize a function of storing the map information acquired by executing the map information acquisition program 64c in the map information storage unit 632b.
Specifically, when the map information is transmitted from the navigation device 100 in response to a request for map information by the execution of the above-described map information acquisition program 64c, the CPU 61 receives the map information in the communication unit 3 and receives the map information. The map information is stored in the map information storage unit 632b.
The CPU 61 functions as a storage control unit by executing the storage control program 64d.

The deletion program 64e is, for example, located at a position away from the current position P detected by the execution of the current position detection program 64a by a predetermined second range R2 or more in the map information stored in the map information storage unit 632b in the CPU 61. This is a program for realizing the function of deleting map information.
The CPU 61 functions as a deletion unit by executing the deletion program 64e.

Here, the map information deletion process by the execution of the deletion program 64e will be described with reference to FIGS.
As described above, the CPU 61 executes the above-described current position detection program 64a while specifying the coordinates (latitude / longitude) of the current position P of the navigation device 100 while the vehicle on which the navigation device 100 is mounted is running. Then, the above-described specifying program 64b is executed to specify the traveling direction of the navigation device 100.

When the current position P and the traveling direction of the navigation device 100 are specified, the CPU 61 determines an area existing within a predetermined second range R2 from the current position P. Here, it is assumed that the second range R2 from the current position P is a semicircular area having a radius of 50 km centered on the current position P and directed in the opposite direction to the traveling direction, and is shaded in FIGS. Part.
In the example of FIG. 10, it is determined that the areas existing within the predetermined second range R2 from the current position P are Osaka Prefecture with the area code “6-3” and Nara Prefecture with “6-4”. Then, the CPU 61 has an area other than the area existing within the predetermined second range R2 (eg, “6-1” Shiga Prefecture, “6-2” Kyoto Prefecture, “6-6” Hyogo Prefecture, etc.). It is determined whether or not the map information is stored in the map information storage unit 632b. If the map information is stored, the map information is deleted from the map information storage unit 632b. In addition, at the time of FIG. 10, the map information of areas other than the area existing within the predetermined second range R2 has already been deleted.
Then, after that, when the vehicle continues to travel further, for example, when the vehicle is located at P in FIG. 11, the Osaka prefecture of “6-3” is within the predetermined second range R2 from the current position P. If it is determined that the area that is out of the existing area and within the predetermined second range R2 from the current position P is only “6-4” in Nara Prefecture, the CPU 61 determines that the map of “6-3”. It is determined whether the information is stored in the map information storage unit 632b. If the information is stored, the map information is deleted from the map information storage unit 632b.

  Note that the second range R2 from the current position P is not limited to the semicircular area illustrated in FIGS. 10 and 11, and may be a circular area such as 270 degrees and 360 degrees. May be a polygonal region or the like.

Next, map information acquisition / deletion processing executed by the CPU 61 will be described with reference to the flowchart of FIG.
First, in step S <b> 1, the CPU 61 specifies the current position P of the navigation device 100 based on the current position detection signal output from the current position detection unit 1. Next, in step S2, when map information of an area other than the area existing within the predetermined second range R2 from the current position P is stored in the map information storage unit 632b, the map information is displayed as map information. It deletes from the memory | storage part 632b.

In step S3, the CPU 61 identifies the traveling direction of the navigation device 100 based on the traveling direction detection signal output from the direction detecting unit 2, and in step S4, refers to the area code storage unit 632a to identify the current Based on the position P and the traveling direction, the adjacent area and the approach area are specified. In step S5, the CPU 61 determines whether or not the distance from the current position P to the approaching area is equal to or less than a predetermined value D. If the CPU 61 determines in step S5 that the distance from the current position P to the approach area is not less than or equal to the predetermined value D (step S5; No), the CPU 61 proceeds to step S8, while the distance from the current position P to the approach area. If it is determined that the distance is equal to or less than the predetermined value D (step S5; Yes), the process proceeds to step S6.
In step S6, the CPU 61 determines whether or not the map information of the approach area is stored in the map information storage unit 632b. If the CPU 61 determines in step S6 that the map information of the approaching area is stored in the map information storage unit 632b (step S6; Yes), it returns to step S1 and repeats the above processing, while the map information storage unit If it is determined that it is not stored in 632b (step S6; No), a map information request signal for requesting map information of the approaching area is transmitted to the information providing apparatus 200 via the network N in step S7. And the map information of the approach area transmitted from the information provision apparatus 200 based on the said map information request signal is acquired in the communication part 3, It returns to step S1 and repeats the above process.

In step S8, the CPU 61 determines whether or not there is an area other than the approaching area within the predetermined first range R1 from the current position P. If it is determined that there is no area other than the approaching area within the predetermined first range R1 from the current position P (step S8; No), the process returns to step S1 and the above processing is repeated. If it is determined that there is an area other than the approaching area in the first range R1 (step S8; Yes), the process proceeds to step S9.
In step S9, the CPU 61 determines whether or not map information of an area other than the approaching area existing within the first range R1 from the current position P is stored in the map information storage unit 632b. If the CPU 61 determines in step S9 that map information of an area other than the approaching area existing in the predetermined first range R1 is stored in the map information storage unit 632b (step S9; Yes), the process proceeds to step S1. Returning and repeating the above process, on the other hand, if it is determined that the map information of the area other than the approaching area existing in the predetermined first range R1 is not stored in the map information storage unit 632b (step S9; No), In step S <b> 10, a map information request signal for requesting map information of an area other than the approaching area existing in the predetermined first range R <b> 1 is transmitted to the information providing apparatus 200 via the network N. And the map information transmitted from the information provision apparatus 200 based on the said map information request signal is acquired in the communication part 3, It returns to step S1 and repeats the above process.

According to the navigation apparatus 100 of the present embodiment described above, the current position P is detected by the execution of the current position detection program 64a by the CPU 61, the travel direction of the navigation apparatus 100 is specified by the execution of the specifying program 64b, and the map By executing the information acquisition program 64c, map information divided into predetermined area units is acquired via the network N, and by executing the storage control program 64d, the map information acquired by executing the map information acquisition program 64c is converted into a map. Map information of an approaching area that is stored in the information storage unit 632b and that is adjacent to the traveling area and exists in the travel direction specified by the execution of the specific program 64b is acquired by executing the map information acquisition program 64c. Is done.
Therefore, in the navigation device 100 using the map information downloaded via the network N, the map information of the adjacent area existing in the traveling direction is acquired, so the map information can be acquired more efficiently. .

Further, the map information of the approaching area is acquired when the distance between the current position P and the approaching area is equal to or less than the predetermined value D by the execution of the map information acquisition program 64c by the CPU 61.
Therefore, when an appropriate distance is set as the predetermined value D, the map information of the approaching area can be acquired more reliably and the map information can be acquired more efficiently.

In addition, by the execution of the map information acquisition program 64c by the CPU 61, it is determined whether or not there is an area in which no map information is stored in the map information storage unit 632b within the predetermined first range R1 from the current position P. When it is determined that there is an area in which no map information is stored in the map information storage unit 632b within the predetermined first range R1 from the current position P, the map information of the area is acquired.
Therefore, even when the traveling direction changes in the direction of an area different from the area set as the approaching area, the map information of the area can be efficiently acquired in advance.

Further, the position of the map information stored in the map information storage unit 632b away from the current position P detected by the execution of the current position detection program 64a by a predetermined second range R2 or more by executing the deletion program 64e by the CPU 61. The map information for is deleted.
Accordingly, only the map information that is likely to be used can be stored in the map information storage unit 632, the storage capacity of the map information storage unit 632 can be configured smaller, and the map of the entire region is held. The search speed of map information can be improved more than the case, and it can be configured at low cost.

The present invention is not limited to the above embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the map information acquisition / deletion process in a part of the region has been described, but a configuration corresponding to movement in a wider range or a narrow range may be used.

It is a block diagram which illustrates the whole structure of the navigation apparatus in this embodiment. It is a block diagram which illustrates the whole structure of the navigation apparatus of this embodiment. It is a figure which illustrates map information. It is a figure which illustrates an area code storage part. It is a figure for demonstrating the map information acquisition process of an approach area. It is a figure for demonstrating the map information acquisition process of an approach area. It is a figure for demonstrating the map information acquisition process of an approach area. It is a figure for demonstrating the map information acquisition process of the area which exists in the predetermined 1st range of a present position. It is a figure for demonstrating the map information acquisition process of the area which exists in the predetermined 1st range of a present position. It is a figure for demonstrating a map information deletion process. It is a figure for explaining map information deletion processing. It is a flowchart which shows map information acquisition / deletion processing.

Explanation of symbols

100 Navigation device 1 Current position detection unit (current position detection means)
2 Direction detection part (specifying means)
3 Communication Department (Map information acquisition means)
61 CPU (current position detection means, identification means, map information acquisition means, storage control means, determination means, deletion means)
632b storage unit (map information acquisition means)
64a Current position detection program (current position detection means)
64b Specific program (specific means)
64c Map information acquisition program (map information acquisition means, determination means)
64d storage control program (storage control means)
64e Deletion program (deletion means)
N network

Claims (5)

In a navigation device comprising current position detecting means for detecting the current position,
A specifying means for specifying the traveling direction of the navigation device;
Map information acquisition means for acquiring map information partitioned into predetermined area units via a network;
Storage control means for storing the map information acquired by the map information acquisition means in a storage unit;
With
The navigation apparatus characterized in that the map information acquisition means acquires the map information of an approaching area that is adjacent to a traveling area and is present in the traveling direction specified by the specifying means.   The navigation apparatus according to claim 1, wherein the map information acquisition unit acquires the map information of the approach area when a distance between the current position and the approach area becomes a predetermined value or less. . A determination means for determining whether or not there is an area in which the map information is not stored in the storage unit within a predetermined first range from the current position;
The map information acquisition unit acquires the map information of the area when the determination unit determines that there is an area in which the map information is not stored within a predetermined first range from the current position. The navigation device according to claim 1, wherein the navigation device is a navigation device.   And a deletion unit that deletes map information at a position away from a current position detected by the current position detection unit by a predetermined second range or more from the map information stored in the storage unit. Item 4. The navigation device according to any one of Items 1 to 3. In a navigation device comprising current position detecting means for detecting the current position,
A specifying means for specifying the traveling direction of the navigation device;
Map information acquisition means for acquiring map information partitioned into predetermined area units via a network;
Storage control means for storing the map information acquired by the map information acquisition means in a storage unit;
Determining means for determining whether there is an area in which the map information is not stored in the storage unit within a predetermined first range from the current position;
A deletion unit that deletes map information at a position away from the current position detected by the current position detection unit by a predetermined second range or more among the map information stored in the storage unit;
With
The map information acquisition unit is configured to display the map information of an approach area that is adjacent to a traveling area and that exists in the traveling direction specified by the specifying unit, and the distance between the current position and the approach area is When it is acquired when the value is equal to or less than a predetermined value, and the determination means determines that an area in which the map information is not stored in the storage unit exists within a predetermined first range from the current position. A navigation device that acquires the map information of the area.

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