JP2001108454A - Navigation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a navigation device always based on latest map information, attribute information, etc. SOLUTION: Map information to which the period of validity information obtained from a communication data reception part 9 is added, is stored in a rewritable optical disc-in-card memory 6. Based on the data read from an internal clock, the period of validity information added on the road map read out of the optical disc-in-card memory 6 is judged and road information out of the period of validity is deleted from the optical disc-in-card memory 6. Therefore, frequent change in map information and attribute information can be responded at once and a user can obtain always latest information without much labor and time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle navigation device for detecting a traveling position of a vehicle, and more particularly to a navigation device having a rewritable memory.

[0002]

2. Description of the Related Art A car navigation system requires a large-capacity map memory.
In the navigation device described in Japanese Patent Publication No. 15 (1999), a semiconductor memory, a cassette tape, a compact disk ROM
A storage device such as a (CD-ROM) is applied. Further, in a navigation device that is actually commercialized and sold, CD-ROs are required to store hundreds of megabytes of road map data nationwide and access them at high speed.
The M device is used as a map memory.

[0003]

However, CD-ROMs
The apparatus can read out a large amount of data stored in advance on an optical disk at a relatively high speed, but cannot rewrite the data or add data. Therefore, when a new road is added or when the attribute information of the map (such as the name of a place, the name of a road or a building) is changed, a new optical disk must be newly created. However, there is a limit to upgrading the optical disc in response to the frequently changing map data, and a burden is increased for a user who purchases the optical disc. Eventually, the optical disk containing old data is often used, and as a result, the accuracy of detecting the position of the vehicle is reduced, and the possibility of giving incorrect attribute information to the user is increased.

[0004] It is therefore an object of the present invention to provide a navigation device which always corrects to the latest map information and attribute information.

[0005]

In order to solve the above-mentioned problems, a navigation device according to the present invention comprises means for detecting a vehicle position and map information to which expiration date information sent from a station provided on a road is added. And means for storing map information not included in the already stored map information together with expiration date information. Then, a means is provided for determining whether or not the map information stored in the storage means is valid based on the expiration date information added to the stored map information.

[0006] The navigation apparatus further includes a communication unit for receiving map information.

The map information may be road data, road regulation data, road congestion data, attribute data such as buildings and place names, and a link cost table for calculating an optimum route.

In the above navigation apparatus, the map information to which the expiration date information is added is received, and the map information is stored or corrected. For example, when the map information received by the communication means is not recorded in the map memory, the received map information is stored in the map memory, and the validity of the previously received map information recorded in the map memory is stored. The expiration date may be checked, and if the expiration date has expired, the map information previously recorded in the map memory may be deleted. Thus, for example, it is possible to promptly respond to a case where map information is changed or new map data is added, and more accurate navigation based on the latest map information or attribute information is always possible.

[0009] Further, by adding a communication means for receiving map information to the navigation device, a large amount of information on various maps sent from the communication means is stored, and correction of the map information is performed. Additions can be made automatically upon receipt. Also, when calculating the optimal route to the destination using information on the length of the road link and information on the congestion of the road sent from the communication means, it was created to represent the degree of connection of the road link, etc. Since the link cost table can also be stored in the map memory sequentially, the route calculation can be remarkably speeded up.
Frequently changing congestion information only needs to correct the link cost of that part, so that the latest information can always be prepared with less effort.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a navigation device according to an embodiment of the present invention.
1 shows a configuration of a system in which a rewritable optical disk device is applied to a navigation device. In the figure, reference numeral 1 denotes a main operation unit constituted by a processor, 2 denotes a memory constituted by a ROM and a RAM, 3 denotes a display unit, 4 denotes an audio output unit,
Reference numeral 5 denotes a man-machine interface unit having an input / output device, 6 denotes an information storage unit composed of an optical disk in-card memory, 7 denotes a traveling distance detection unit that measures a traveling distance, 8
Denotes a traveling direction detector that measures the traveling direction.

In such a configuration, the main processing unit 1 collects data by controlling various sensors and input devices, calculates a running position using the ROM and RAM of the memory 2 based on the collected data, and as a result, , And controls an output device such as a display and outputs a result (that is, displays necessary position information and the like on the display).

The display section 3 visually displays map information, a running position of a car, and the like on a plane. For example, it is desirable to use a flat display such as a liquid crystal or EL (electroluminescence). This is because the navigation device can be downsized as a whole by using these components, so that the navigation device can be easily mounted in the vehicle interior.

The audio output unit 4 is used as a means for transmitting route guidance and various kinds of guidance to a driver, and outputs an audio synthesis signal and digital audio recorded in a ROM or an optical disk in-card memory.

The information storage unit 6 composed of an optical disk in card memory is a large-capacity, high-speed information recording device for recording information necessary for navigation such as map information and road information. In particular, the card memory 6 is characterized in that the size of the memory medium is reduced to the size of a credit card so that both reading and writing of information are possible, and the size of the memory medium is convenient for carrying around. However, the information recording unit 6 may use, for example, a magneto-optical disk or a fixed disk instead of the above-described optical disk in-card memory. Also, a CD-ROM device that can only be read and an optical disk in-card memory may be used in combination. The traveling distance detection unit 7 that detects the traveling distance of the vehicle can use, for example, a wheel speed sensor that determines the vehicle speed from the rotation speed of the axle of the vehicle, a spatial filter, or the like. Further, as the traveling direction detector 8 for detecting the traveling direction of the vehicle, a steering angle sensor for determining the direction from the difference between the rotational speeds of the left and right wheels of the vehicle, an optical fiber gyro, a vibration gyro, or the like can be used.

FIG. 2 shows an example of the screen 15 displayed on the display unit 3. As shown in FIG. Reference numerals 16 and 17 in the figure indicate the displayed road map and the traveling locus of the vehicle, respectively, and show an example in the case where the vehicle travels on the displayed map as indicated by a broken line 17. ing. With this example, the operation of the navigation device of the present invention having the above-described configuration will be described below.

FIG. 3 shows a flowchart of the operation of the navigation device. In this flowchart, first, sensor data is read from the traveling distance detector 7 and the traveling direction detector 8 (step 101), and a traveling vector at that moment is calculated. Further, the initial position may be set by the user or measured using an absolute position sensor such as a global positioning system (GPS). By using this travel vector and comparing it with the road map data read from the optical disc in-card memory unit 6 (step 102) (step 103), it is possible to correct an error generated from each sensor. That is, in FIG. 2, road map data close to the travel vector (broken line 17) exists for routes A to D and EG, and the travel locus can be compared with the road data (step 1).
04). However, for the routes D to E, there is no road data close to the traveling locus, and in this case, dead reckoning which simply connects the traveling vectors is performed (step 10).
5) At the same time, if it can be considered that the road data of this part is missing, the driving vector (driving locus) obtained from the sensor data is converted into road map data,
The data is additionally stored in the optical disk in-card memory unit 6 (step 106). The running positions thus obtained are sequentially displayed on the display unit 3, and then the sensor data at the next timing is read. Thereafter, the same steps as above are repeated.

As described above, according to the navigation device of the present invention, by using a rewritable optical disk as a road map memory, it is possible to easily add data such as newly created roads to the database. Become. Further, correction or addition of road data or the like may be manually performed by the user using the input device while viewing the display screen.

FIG. 4 is a plan view of an optical disk in card used in the optical disk in card memory section of the apparatus shown in FIG. In this figure, reference numeral 41 is an optical disk,
Reference numeral 42 denotes a case in which an optical disc is built, and 43 denotes a window for irradiating the optical disc with light.

The optical disk in card used in the navigation device according to the present invention has an optical disk 4
1 is rotatably housed, and irradiates light through a window 43 formed in a case to record information on the optical disk 41. The window 43 is preferably formed of a transparent member, and light is preferably applied to the optical disc 41 through the transparent member. With such a structure, the thickness of the optical disk can be reduced to 1.2 mm or less, so that the entire optical disk including the case 42 becomes very compact, and the portability can be significantly improved.

Further, the optical disk in card used in the present invention is a thin card which is easy to carry and has a large capacity with the case 42 formed in a credit card size. Reference is made to the specification and drawings attached to Japanese Patent Application No. 1-249154, already filed by the same applicant as the present application, and to which reference is made. In addition, since the optical disk in card can be put into and taken out of the storage device with the case, it is possible to prevent the attachment of dust and the like, and the handling is very simple.

This optical disc in card has a large capacity of 30 MB or more in terms of performance and can transfer information at a high speed. Can also be easily applied. Also, information in which images and characters are mixed, such as newspapers and catalogs, can be stored. Further, when information is recorded by a short wavelength laser, 1
This is an extremely excellent information recording medium that allows a storage capacity of 00 MB or more.

FIG. 5 illustrates the structure of an optical disk used for the optical disk in card shown in FIG. In the figure, reference numeral 51 indicates a directory part, and 52 indicates a main data part. Information such as map data is stored on the optical disc 4
In a directory section 51 set in a part of the optical disk 41, coarse data obtained by sampling the information contents, keywords, indexes, titles, and the like are recorded so that the rough contents of the stored information can be understood. Then, it is recorded separately from all the stored data. The stored information is managed by using this directory, and the search for the target information can be speeded up. The search using this directory is managed by the main processing unit 1 shown in FIG.

Further, information recorded in the main data section 52 of the optical disc is distinguished into necessary information and unnecessary information,
It is preferable that new information is overwritten on unnecessary information, so that the recording capacity can be effectively used. Such management is also performed by the main processing unit 1. When recording moving image information, it is preferable to use a moving image recording method in which image information and audio information are recorded on the same track, and audio information is inserted into the image information so that they are synchronized.

FIG. 6 is a conceptual diagram of the optical disk in-card memory unit 6 described above. In the figure, reference numeral 61 denotes an information recording / reproducing apparatus for recording / erasing information on / from the optical disc in-card 62 and reproducing the recorded information.

Table 1 shows the specifications of the memory unit.

[0027]

[Table 1]

As shown in Table 1, when the case 42 is of a credit card size, the optical disk size is about 1.9 inches and the recording capacity is 30 MB. Further, when the wavelength of 830 nm currently used is shortened to half the wavelength, a large capacity of 120 MB or more, which is four times larger, can be realized. Further, the data transfer speed is 5 Mb / sec at a disk rotation of 3600 rpm. The access time is as short as 100 msec, the information can be transferred at high speed, and it is particularly suitable for storing road map data of a navigation device.

FIG. 7 shows the configuration of the information recording / reproducing apparatus used in the embodiment of the present invention. That is, the information recording / reproducing apparatus records information on an optical disc,
An optical head 1210 for performing at least one of reproducing information recorded on an optical disc and erasing information recorded on the optical disc;
For example, a motor 1240 which is a rotating means for rotating the motor 40
And the like, the optical head 1210 and the rotating means 1240
And a drive circuit 1260 for controlling the operation of. Also, preferably, a processor 1400 for giving an instruction to the drive circuit 1260 and the processor 1460
The processor 1400 has input means 1500 for inputting information, and output means 1600 for outputting information from the processor 1400. FIG. 8 is a cross-sectional view of the optical system when an optical disc in card is inserted into the information recording / reproducing apparatus shown in FIG. Reference numeral 41 in the figure denotes an optical disk, reference numeral 42 denotes a case,
Reference numeral 71 denotes a drive case,
Reference numeral 72 denotes a substrate forming the prism 73 and the objective lens 74, respectively. Here, when information is recorded on the optical disk 41, the light is condensed by the objective lens 74, and is passed through the transparent portion of the case 42.
Is irradiated with light. The optical disc in-card used in the present embodiment has a thin overall thickness of the optical disc in-card including the case 42 of 2 mm or less, and is extremely compact, portable and operable. And the like can be significantly improved.

In this case, the information recording / reproducing apparatus 61 is reduced to 15 mm or less by reducing the effective diameter of the objective lens 74, the beam diameter of the light entering the prism 73, and the like, and reducing the surface deflection caused by the rotation of the optical disk 41. Can be installed in any small space inside the vehicle,
It becomes possible to arrange them appropriately.

FIG. 9 is a plan view showing an optical system of an information recording / reproducing apparatus constituting an optical disc in-card memory section. FIG. 10 is a plan view showing an information recording / reproducing apparatus constituting the above-mentioned optical disc in-card memory section. FIG. 3 is a cross-sectional view showing the optical system of FIG. 8 and 9, reference numeral 81 denotes a semiconductor laser, 82 denotes a collimating lens, 83 denotes a polarizing prism, 84 denotes a shaping prism, 85 denotes a rising mirror, 86 denotes an objective lens, and 87 denotes an objective lens. Reference numeral 86 denotes an effective diameter, 88 denotes a photodetector, and 89 denotes a substrate on which these are arranged. By configuring the optical system as shown in these figures, it is possible to reduce the size of the optical head and, consequently, to reduce the size of the entire information recording / reproducing apparatus.

As described above, since the optical disk device (optical disk-in-card memory unit) employed in the navigation device of this embodiment is very small, a plurality of optical disk devices can be used if necessary. For example, this makes it possible to have map data for each region, and also to divide discs for each type of information. Furthermore, the optical disk device (optical disk in-card memory unit) of the present embodiment is more excellent in earthquake resistance than a storage device such as a magneto-optical disk device, and at least a CD.
-It has a vibration characteristic equivalent to that of a ROM device, so that it is particularly suitable as a rewritable large-capacity memory to be mounted on an automobile where problems due to vibration are inevitable.

[Embodiment 2] FIG. 11 is a block diagram of a device in which a communication device is further applied to a navigation device in addition to a rewritable disk. In FIG.
Reference numeral 9 designates a so-called communication data receiving unit which receives information transmitted from an external communication device, particularly added in this embodiment. The communication data receiving unit 9 receives radio waves transmitted from a road station provided on a road and obtains various information necessary for a mobile body, such as road map information, travel position correction information, traffic congestion, and regulation information. belongs to.

FIG. 12 shows a mobile unit 23 equipped with a navigation device according to a second embodiment of the present invention and a road station 22.
2 shows an outline of communication between the server and the server. Here, the base station 21
Collects traffic congestion status and traffic regulation information on roads in charge in real time. For example, road map information, travel position correction information used in navigation, and the like are added to the collected information, and the road stations 22 located at a plurality of locations facing the road move within the line-of-sight range. Body 23
To transmit information wirelessly. Moving objects 23 such as automobiles
Collects this information, selects the necessary information
The data is recorded in the memory 2 or the optical disk in-card memory 6 (see FIG. 11). Here, the optical disk in-card memory 6 is a non-volatile memory and has a large capacity and rewritable, as is clear from the characteristics described in detail above.
In particular, it is suitable for the above applications.

FIG. 13 is a flowchart showing one method of recording information obtained from the communication device. Here, the main processing unit 1 always monitors whether the communication data receiving unit 9 can receive data (step 201). If it is determined that the data cannot be received (NO), the travel position calculation is continued. On the other hand, if it is determined that the data can be received (YES), the data from the communication data
It is temporarily stored in the M memory 2 or the like (step 202). The data is further analyzed and map information is first selected. It is checked whether or not this map information is included in the map information recorded in the optical disk in-card memory 6 (step 203).
If it is determined that the map information is not included (YES), the map information is recorded in the optical disk in-card memory 6 (step 204).

Next, road information such as traffic regulation information is selected and it is checked whether or not this information is recorded in the optical disk in card memory (step 205). The road information is recorded in the card memory 6 (step 206).

After the above processing is completed, the sensor data from the traveling distance detecting section 7 and the traveling direction detecting section 8 are read (step 207), and based on these, the main arithmetic section 1 performs an arithmetic operation, for example, by dead reckoning or the like. The running position of the car is obtained (step 208). As described above, the determination of the traveling position may be performed using data from radio navigation such as the Global Positioning System (GPS), or a hybrid system combining dead reckoning navigation and radio navigation. You may go.

Thereafter, based on the traveling position information obtained above, the map information including the current position is read from the optical disk in-card memory 6 and the current traveling point of the vehicle is displayed on the map displayed on the display unit 3. Is marked and displayed on the display (step 209).

FIG. 14 shows one method of recording information obtained from the communication device. In the figure, first, the main processing unit 1 always monitors whether or not the communication data receiving unit 9 can receive data (step 211). As a result, when it is determined that the data cannot be received (NO), the traveling position calculation described later is continued. On the other hand, if it is determined that the data can be received (YES), the data from the communication data receiving unit 9 is temporarily stored in the RAM memory 2 or the like (step 2).
12).

Next, map information is read from the optical disk in-card memory 6 (step 213), and is compared with map information included in the collected received data to determine whether or not they match (step 214). As a result of this comparison, if the maps do not match in the same area (NO), it is determined that the newly collected data is correct, and the map is corrected (step 215).

Similarly, road information such as traffic regulation information is read from the optical disc in-card memory 6 (step 216), and it is compared whether or not the road information is included in the collected received data (step 217).
That is, if the road information does not match in the same area (NO), the newly collected data is determined to be correct information and is corrected (step 218).

After the above processing is completed, the sensor data from the traveling distance detecting section 7 and the traveling direction detecting section 8 are read (step 219), and based on these sensor data, the main computing section 1 computes and performs dead reckoning navigation. Thus, the traveling position of the automobile is obtained (step 220). In addition, the determination of the traveling position
Similar to the above, it may be performed by data from radio navigation such as the Global Positioning System (GPS), or by a hybrid system combining dead reckoning and radio navigation. Thereafter, the map information including the current position is read from the optical disk in-card memory 6 based on the vehicle travel position information obtained as described above, and the current travel point is marked and displayed on the map on the display 3.

FIG. 15 is a flowchart showing an example of a method for updating old road information. First, every time the navigation device is started up, the main processing unit 1 reads a date from a clock built in the navigation device (step 231). Next, the optical disk in-card memory 6
Is read (step 232). These pieces of information include information that is only valid for a certain period, such as road construction information. The main processing unit 1 determines whether there is any information whose validity period has passed (step 233). Only the data determined to have passed the time limit is selected and deleted from the optical disk in-card memory 6 (step 23).
4). After the above processing is completed, a normal navigation operation is started (step 235).

Next, FIG. 16 shows a position embodiment of a method of calculating an optimum route using the above-mentioned map information, road information and the like. In this method, first, for example, by using the man-machine interface unit 5 in the configuration diagram shown in FIG. 11, the start point and the end point of the route to be obtained, and further,
Optimal conditions (shortest time, shortest distance, etc.) are input (step 301). Further, the main processing unit 1 always monitors whether or not the communication data receiving unit 9 can receive data (step 302). As a result, when it is determined that the data can be received (YES), the data from the communication data receiving unit 9 is stored in the RAM.
It is temporarily stored in the memory 2 or the like (step 303). On the other hand,
If it is determined that data cannot be received (NO), the process skips step 303 of collecting communication data, and continues the route calculation without collecting data. That is, thereafter, the road map data near the start point and the end point and between them is read (step 304).

When the shortest route of distance or time is calculated, a method called the Dijkstra method is usually used. At this time, if a table called a link cost table indicating the connection status of the road network is prepared in advance, the speed of the route calculation can be increased. When communication data cannot be received, the link cost is represented by the length of each road (link). When communication data can be received, the link congestion information and the like included in the communication data is expressed as the cost of each link ( Weight).

The link cost table requires a large-capacity memory as the target road network increases, and the link cost must be changed frequently due to changes in congestion information and the like. Thus, as shown in FIG. 16, the created link cost table is stored in the rewritable optical disk in-memory section 6 (step 305). As a result, it is not necessary to create a table once created, and it is possible to cope with congestion information that changes every moment by simply correcting the link cost of that part, thereby significantly speeding up route calculation. it can.

Thereafter, the optimum route is searched for by the Dijkstra method using the link cost table stored in the optical disk in-card memory section 6 (step 30).
6) Display the obtained optimal route (step 30)
7). In addition, it is determined whether or not the next candidate or the like is necessary (step 308). As a result, if necessary (YES), the process returns to step 306 again to calculate again using the link cost table.

FIGS. 17 and 18 are diagrams for explaining an example of the link cost table 31 described above. FIG. 17 shows the displayed road map 16. In the figure, N1 to N13 represent node (node) numbers, and... Represent link costs. In this case, the table 31 corresponds to FIG.
8, a two-dimensional array corresponding to the number of nodes (N1 to N13). Also, the degree of connection between nodes is shown in this table. For example, when N1 and N4 are connected by link cost, the link cost is stored in row N1 and column N4. Each time such a table is created, it is stored in the optical disk in-card memory unit 6 described above,
In addition, each time there is a change in the link cost, only that portion is corrected, whereby the speed of the route calculation can be increased.

[Embodiment 3] FIG. 19 shows a navigation system in which a CD-ROM device is added to the above-described second embodiment together with an optical disk in-card memory unit 6 as a rewritable disk, and a communication device is applied to a navigation device. It is a block diagram of an apparatus. In the figure, reference numeral 10 denotes a CD for reading data from a CD-ROM in which a map and attribute information are recorded.
-The configuration of the ROM device is otherwise the same as that of FIG.

The operation will be described below. The main processing unit 1 always monitors whether the communication data receiving unit 9 can receive data. If it is determined that data has not been received, the travel position calculation is continued. If it is determined that data has been received, the data from the communication data
It is temporarily stored in the M memory 2 or the like.

Next, the map information is read from the CD-ROM device 10 and compared with the map information included in the collected received data. If the road information does not match in the same area, the unmatched road is registered in the optical disc in-card memory as a newly prepared and deleted road.

After the above processing is completed, the main arithmetic section calculates the running position based on the sensor data from the running distance detecting section 7 and the running direction detecting section 8 and obtains the running position by dead reckoning navigation. The determination of the traveling position may be performed based on data from radio navigation such as the Global Positioning System (GPS). Further, a hybrid system combining dead reckoning and radio navigation may be used.

Based on the obtained traveling position information, map information including the current position is read from the CD-ROM device 10 and the optical disk in-card memory 6, and the current traveling point is marked on the map and displayed on the display.

As described above, in particular, by employing the above-described optical disk in-card memory 6 as an information recording device of a navigation device, the optical disk memory itself can be stored in a credit card size with a protective case. It is easy to handle because it has excellent properties and can prevent the attachment of dust. In addition, since the memory medium is small, the entire disk device is also reduced in size and weight, and has a unique effect that a limited space such as a vehicle interior can be effectively used.

[0055]

According to the navigation device of the present invention,
Even when a new road is added or the attribute information of the map (such as a place name, the name of a road or a building) is changed, another new optical disk is created as in the case of a conventional map memory such as a CD-ROM. There is no need to perform the operation again, and the map information can be stored or corrected based on the received map information. This frees the user from the burden of every CD-ROM version upgrade, is economical and efficient, and can also respond to frequently changing map data one after another. Information will be available to the user.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a navigation device of the present invention.

FIG. 2 is an example of a display screen for explaining the operation of the embodiment in FIG. 1;

FIG. 3 is a flowchart showing the operation of the embodiment of FIG. 1;

FIG. 4 is a plan view of the optical disc in card.

FIG. 5 is a plan view of an optical disc built in the card shown in FIG. 4;

FIG. 6 is a conceptual diagram of an optical disk in-card memory unit.

FIG. 7 is a conceptual diagram showing a configuration of an optical disc in-card memory unit.

8 is a cross-sectional view of a light irradiation unit when an optical disc in-card is stored in the information recording / reproducing apparatus shown in FIG.

9 is a plan view of an optical system of the information recording / reproducing apparatus shown in FIG.

FIG. 10 is a sectional view of the optical system shown in FIG. 9;

FIG. 11 is a block diagram showing an embodiment in which a communication data receiving unit is added to FIG. 1;

FIG. 12 is a schematic diagram of communication between a moving object equipped with a navigation device and a road station.

13 is a flowchart showing an example of an operation of recording information in the embodiment of FIG.

14 is a flowchart illustrating an example of an operation of recording information in the embodiment of FIG.

FIG. 15 is a flowchart illustrating a method for updating old road information in the embodiment of FIG. 11;

FIG. 16 is a flowchart showing a method of calculating an optimum route in the embodiment of FIG.

FIG. 17 is an example of road data for explaining a link cost table.

FIG. 18 is an example of a link cost table.

FIG. 19 is a block diagram showing an embodiment in which a CD-ROM device is added to FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main calculation part, 2 ... Memory comprised of ROM and RAM, 3 ... Display part, 4 ... Audio output part, 5 ... Man-machine interface part, 6 ... Optical disk in-card memory part, 7 ... Driving distance detection part, 8 ... running direction detecting section, 9
... Communication data receiving unit, 10 ... CD-ROM device, 15 ...
Display screen, 16: displayed road map, 17: travel locus, 31: link cost table, 41: optical disk,
Reference numeral 42 denotes a case in which an optical disk is built in. 43 denotes a window for irradiating the optical disk with light. 61 denotes an information recording / reproducing device.
2. Optical disk in card.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09B 29/10 G09B 29/10 A // G01S 5/14 G01S 5/14 (72) Inventor Junichi Makino Ibaraki 4026 Kuji-cho, Hitachi City, Hitachi, Ltd.Hitachi Laboratory, Hitachi, Ltd. (72) Inventor Yoshio Sato 4026 Kuji-machi, Hitachi City, Ibaraki Prefecture, Hitachi Laboratory, Hitachi, Ltd.

Claims (2)

[Claims] 1. A means for detecting the position of a vehicle, a receiving means for receiving road map information attached with expiration date information sent from a station provided on a road, and a means for transmitting the received road map information to expiration date information. A navigation device that outputs navigation information to an output device, wherein the road map information received by the receiving device is not included in the road map information stored in the storage device. In the case, the means for storing the road map information received by the receiving means in the storage means, and the received road information stored in the storage means based on the expiration date information corresponding to each received road map information. Means for determining whether or not map information is valid. 2. The navigation device according to claim 1, wherein the means for determining an expiration date of the road map information includes:
A navigation device comprising means for deleting road map information determined to have expired.