JP2000155896A - Navigation center device, navigation device, navigation system and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce data amounts to be transmitted from a center side to a mobile side while satisfactorily executing path guidance by transmitting only necessary data which are not overlapped. SOLUTION: The starting place, destination, and segment s SGA-SGG are transmitted from a center side to a mobile side as path and guidance data. The segment SGA are only path data. Then, guidance data DA at the previous time of path retrieval are synthesized with the path data as shown by an arrow FA. The path data and the guidance data are transmitted from the center side to the segment SGB, and guidance executed by using this. The segment SGF is only path data. Then, guidance data DF are synthesized with the path data as shown by an arrow FF. In the same way, the segment SGG is only path data, and guidance data DG are synthesized with the path data as shown by an arrow FG.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation center device, a navigation device, a navigation system, and a method suitable for a system for providing data necessary for route guidance from a center side to a moving side.

[0002]

2. Description of the Related Art In a widely used navigation system, a navigation device is mounted for each moving object, for example, each vehicle, and route guidance is provided for each vehicle using map data stored in a CD-ROM or the like. And so on. However, in such a system, it is necessary to continually purchase a new CD-ROM corresponding to new construction or abolition of a road. Also, if the type of medium is different, such as a DVD-ROM, or if the format is different even if the type is the same, the navigation device itself must be replaced.

On the other hand, Japanese Patent Application Laid-Open No. Hei 10-19588 discloses that a map image and optimum route data necessary for guiding a vehicle to a destination are transmitted from a center (base) side to a vehicle side. A navigation system is disclosed. According to this system, communication is performed between the data transmission system on the center side and the navigation device of the vehicle on the mobile side. The data transmission system has a database that stores data necessary for guiding a vehicle to a destination. The data transmission system reads necessary data from a database based on a request from a navigation device of the vehicle and creates a map image. Further, a route search is performed to create optimal route data. The created map image and data of the optimum route are transmitted to the vehicle. In the navigation device of the vehicle, the corresponding display is performed based on the map image and the data of the optimum route transmitted from the system side.

[0004]

In the background art described above, the entire route data and map data from the departure point to the destination obtained on the center side are transmitted to the mobile side in response to a request for route guidance. Is done. Thus, on the moving side,
From the departure to the arrival at the destination, a map image corresponding to the traveling position is sequentially displayed on the display of the navigation device.

However, for example, when the vehicle travels in the reverse direction and returns from the destination to the departure point, the vehicle travels in the reverse direction unless there are special circumstances such as one-way traffic and road construction. In this case, the route searched on the center side is the same for the outward route and the return route, and the guide data is considered to be substantially the same. Alternatively, the current search route may partially overlap the previous search route.

However, in the background art described above, every time a route is searched, route data and guidance data are transmitted from the center side to the moving side. However, if there is a common part between the existing data transmitted from the center side to the mobile side and the data at the time of this route guidance, there is much waste and communication time and communication cost are increased more than necessary.

The present invention focuses on the above points, and aims to reduce the amount of data transmitted from the center to the mobile side by transmitting only necessary data that does not overlap, shorten the communication time, The goal is to reduce communication costs. Another object is to provide good route guidance even if the amount of data transmitted to the mobile side is reduced.

[0008]

In order to achieve the above object, a navigation center apparatus according to the present invention comprises a data storage means for storing data for route searching and route guidance; utilizing the data in the data storage means. Route searching means for performing a route search; data comparing means for comparing the searched route with the already transmitted route to determine whether or not the guidance data needs to be transmitted; and performing transmission based on the comparison result. Guidance data acquisition means for obtaining necessary guidance data from the data storage means; transmission means for transmitting the route data obtained by the route search means and the guidance data obtained by the guidance data acquisition means to a mobile side; It is characterized by the following. According to one of the main modes, the guidance data acquiring means acquires guidance data included in a peripheral area set at a course change point in the searched route.

The navigation device according to the present invention comprises: data receiving means for receiving data transmitted from the navigation center device; data storage means for storing each data received thereby; received data stored therein;
Data combining means for combining data held by the moving side in advance; and route guidance means for performing route guidance based on the data combined thereby. One of the main modes is characterized in that the data held in advance by the mobile side is already transmitted data transmitted from the navigation center device.

[0010] A navigation system according to the present invention includes any one of the navigation center devices and any one of the navigation devices. One of the main modes is characterized in that the data is transmitted and received in units of segments that can be guided.

According to the navigation method of the present invention, a step of searching for a route on the center side; a step of comparing the searched route with a route already transmitted to determine whether transmission is necessary; Obtaining the guidance data that needs to be transmitted based on the data; transmitting the searched route data and the guidance data to the mobile side; combining the transmitted data with the data held in the mobile side in advance. Performing a route guidance based on the combined data. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. In the following embodiment, a vehicle is assumed as a moving side, and a case where the present invention is applied to an in-vehicle navigation device will be described as an example.

First, the outline of the following embodiment will be described. On the vehicle side, search basic data indicating the starting point and the destination of the route search is transmitted to the center side. On the center side, a route search is performed with reference to the database. Then, the searched route is compared with the previous route already transmitted to the vehicle. As a result, since the guidance data exists on the vehicle side for the previously transmitted route, the guidance data is extracted for other routes.
Then, the route data and the guidance data not present on the vehicle side are transmitted to the moving side. On the moving side, the route / guidance data (route data and guidance data) transmitted from the center and the corresponding part of the route / guidance data previously obtained from the center are combined. Then, map display and voice guidance are performed based on the route / guidance data after the synthesis.

[0014]

Embodiment 1 (1) Overall Configuration First, an overall configuration of Embodiment 1 will be described with reference to FIG. FIG. 1 shows a configuration of a navigation system according to the present embodiment. The navigation system according to the present embodiment includes a center device 150 on the center side and an in-vehicle navigation device 100 on the moving side.

First, the center device 150 will be described.
The communication control unit 151 is a communication device including a modem, a terminal adapter, and the like, and transmits and receives data to and from the navigation device 100. A communication system such as a car phone, a mobile phone, and a PHS may be used. The system control unit 152 includes an arithmetic processing device including a CPU and a memory. In the memory, a route search program that searches for a route from the designated departure point to the destination, a program that extracts guidance data on the searched route, a program that compares the searched route with the previous and current times, etc. In addition, various programs executed by the center device 150 are stored. Also, a working area used for executing those programs is secured in the memory.

The database 153 is a large-capacity storage medium such as a hard disk, and includes route data (road number and intersection number) representing a route, search data used for route search, guide data for guiding the searched route, and the like. , Data necessary for route search and route guidance are stored. The specific contents are as follows, for example. Map data: Data for displaying a map on the display of the navigation device. Road data ... As shown in FIG.
The information includes node point numbers and positions (longitude / latitude), road names, road types, road lengths, drawing data, and the like set on each road. The road drawing data may be vector data composed of a plurality of drawing coordinates or bitmap image data. Intersection data: As shown in FIG. 2 (B), an intersection number sequence, an intersection name, a position (longitude / latitude), a guidance voice for instructing a direction change direction of the intersection, a so-called landmark serving as a guide mark, Data such as the landscape of the building.
Note that the intersection includes a branch point. Search data: Data for specifying the position (longitude and latitude) of the destination from a telephone number, address, name, and the like. Previous route data... As shown in FIG. 2C, the route data is obtained at the time of the previous route search for each vehicle. This route data is held together with the vehicle ID.

Next, the on-vehicle navigation device 100 will be described. The arithmetic processing unit 101 is mainly composed of a CPU. The program storage unit 102 stores the route / guidance data transmitted from the center apparatus 100 (in some cases, only the route data) and a program for synthesizing a corresponding part of the previous route / guidance data, the route / guidance data. It is a memory for storing programs to be executed by the arithmetic processing unit 101, such as a program for displaying a route on the display unit 106 based on the information and a program for outputting guidance voice from the audio output unit 107.

The data storage unit 103 functions as a working area appropriately used when executing a program, and stores, for example, the following data. Route / guidance data transmitted from the center device 150, vehicle-specific ID data, vehicle position data (longitude / latitude) measured by the position measurement unit 104,

Among these, the vehicle position data includes a plurality of past position data in addition to the current position data measured at predetermined time intervals by the position measuring unit 104. For example, position data of measurement points included in a certain distance or position data of a certain number of measurement points are stored. When the position is newly measured by the position measurement unit 104, the latest position data is stored and the oldest stored position data is deleted. By connecting these plurality of position data, the traveling locus of the vehicle can be obtained.
This traveling locus is used for so-called map matching for specifying the road on which the vehicle is traveling.

Next, the position measuring unit 104 is a so-called GP
A GPS receiver that measures the position of a vehicle using S, D-GPS, etc., receives signals from a plurality of GPS satellites, measures the absolute position of the vehicle, and measures the relative position of the vehicle. Speed sensor, direction sensor, etc. Speed sensors and direction sensors are used for autonomous navigation. The relative position measured by those sensors is GP
It is used for obtaining a position in a tunnel where the S receiver cannot receive a radio wave from a satellite, or for correcting a positioning error of an absolute position measured by a GPS receiver.

The input unit 105 includes various switches, a touch panel attached to the display surface of the display unit 106, a remote controller, a data input device using voice recognition, and the like. In the touch panel, when a user touches an icon or the like displayed on the display unit 106 with a finger, corresponding data or an instruction is input. In a data input device using voice recognition, when a user utters a voice, data or a command corresponding to the voice is input.

The display unit 106 is a display such as a liquid crystal display or a CRT, and has a touch panel as described above. The transmission / reception unit 108 is a communication device for transmitting and receiving data to and from the center device 150, and includes a modem and the like. A system such as a car phone, a mobile phone, and a PHS may be used.

(2) Data segment ... Next, the form of data handled in this embodiment will be described. Route data and guidance data are transmitted and received between the center and the vehicle. In this embodiment, data is transmitted and received in units of segments. That is, the minimum data unit necessary for route guidance on the vehicle side is a data segment, and data is transmitted from the center side to the vehicle side for each segment.

The segments are, for example, as shown in FIG.
It is represented by a combination of a road number R200 and its end intersection number C2. The data of this segment includes road data: road name, road length, road type, road drawing, etc. (see FIG. 2 (A)) relating to the road with road number R200; intersection data: intersection number C2. Names of intersections, attributes of intersections, positions of intersections, so-called landmarks M201 and M202 near intersections, connecting roads R
Each data such as 201 and R202, voice guidance (FIG. 2
(See (B)).

For example, it is assumed that the searched route is a route as shown in FIG. In the figure, a bold line indicates a search route, and numbers R00, C are provided on a route from the departure place S to the destination G.
00, R10, C10, R20, C20, R30, C3
Roads and intersections of 0, R40, C40, R50 exist in order. Further, for example, at the intersection C00, roads R01,
R02 is connected, and road R11 is connected to intersection C10. The same applies to other intersections. The file of the route / guidance data in such a case is as shown in FIG. Among them, the segment SG1 is a combination of the route data and the guidance data on the roads and intersections of numbers R00 and C00. Also, the number R1
The segment SG2 is a combination of the route data and the guidance data for the roads 0 and C10 and the intersection. Hereinafter, the same applies. The last segment SG6
Is only data relating to the road with the number R50.

(3) Route Search and Guidance Data Extraction Next, the operation of route search and guidance data extraction will be described with reference to the flowchart of FIG. In the in-vehicle navigation device 100, first, the GPS data is acquired by the position measurement unit 104, and the current position (longitude / latitude) of the vehicle is measured. On the other hand, the in-vehicle navigation device 100
Uses the input unit 105 to input a destination facility name, a telephone number, an address, or the like. Then
The current vehicle position is transmitted as departure point data, and the telephone number and address of the destination are transmitted to the center device 150 together with the vehicle ID as destination data.

These data are received by the communication control unit 151 of the center device 150 (Y in step S1) and sent to the system control unit 152. Then the system control unit 1
At 52, a departure place and a destination are determined based on the received data. First, as the starting point of the route search, an intersection at or near the current position of the vehicle is set based on the current position data of the vehicle transmitted from the vehicle-mounted navigation device 100. On the other hand, as for the destination, the database 153 is referred to, and the location of the facility corresponding to the telephone number and the address transmitted from the in-vehicle navigation device 100 is read from the database 153. And
The read facility location or an intersection near the facility location is set as a route search destination (step S).
2).

In the center device 150, a route search is performed based on the departure place and the destination determined as described above (step S3). That is, the system control unit 15
In step 2, a route search program is executed based on the data of the departure place and the destination, and a recommended route from the set departure place to the destination is searched. As a method of this route search, for example, the distance from the departure point to the destination is the shortest, the running time is the shortest, the waypoint is taken into account, VI
Various methods are known, such as adding traffic congestion data and road construction data obtained from CS and the like. The searched route is, for example, as shown in FIG. The data of the searched route is stored in the database 153.

Next, in the center device 150, the route searched as described above is compared with the route searched in the previous route search. That is, the already transmitted route data corresponding to the ID of the corresponding vehicle is referred to, and it is determined whether or not the guidance data on the current search route has already been transmitted to the vehicle (step S5). S6). This determination is performed for all segments by setting a counter indicating the number of segments (steps S4 and S4).
10, S11).

For example, when the guide data of the i-th segment has already been transmitted (Y in step S6), the number transmission flag for transmitting only the route data of the road and the intersection included in the segment is set to "ON". (Step S7). Conversely, when the guidance data of the i-th segment is new data that has not been transmitted (N in step S6), the segment transmission flag for transmitting each data of the route and the guidance included in the segment is set to “ON”. (Step S8). Then, guidance data corresponding to the segment is extracted from the database 153 (step S9). Note that the parentheses in step S9 will be described later.

The route / guidance data of the segment with the segment transmission flag “ON” and the route data of the segment with the number transmission flag “ON” obtained as described above are arranged in the order of the route (the order used on the vehicle side). Is transmitted to the in-vehicle navigation device 100 of the vehicle having the corresponding ID (step S12). The transmitted data is stored in the data storage unit 103
Is stored. On the other hand, the route data is stored in the center device 150.
In the system control unit 152, the ID of the corresponding vehicle
Stored with Such route search, extraction of guidance data, and transmission thereof are performed by the center device 150 in response to a request from each vehicle.

For example, at the time of the previous route guidance, a route as shown in FIG.
It is assumed that the guidance data has been transmitted to the vehicle. Then, it is assumed that the route at the time of the current route search is a route indicated by a bold line in FIG. Due to circumstances such as road construction, lane regulation, differences in waypoints, and search conditions such as time priority or distance priority, the route on the way may be different even though the departure place and destination are the same as shown in the figure. Comparing both,
Last time …… C10 → R20 → C20 → R30 → C30 ...
... but this time ... C10 → R11 → C70 → R
80 → C80 → R31 → C30 ... Therefore, from the departure point S to the intersection C00 and from the road R40 to the destination G, the guidance data has already been transmitted to the vehicle.

Therefore, in the present embodiment, the segment data including the route from the departure point S to the intersection C00 and the segment including the road R40 to the destination G, which are the routes common to the previous time and this time, indicate the route data, that is, the route. Only the data of the road number and the intersection number are transmitted. For segments including C10 to C30, which are different routes between the previous and current times, route data and guidance data are transmitted.

As a result, the current route / guidance data file is as shown in FIG. First, there are coordinate data of the starting point and the destination at the head of the file. Next, segment S
GA is only the route data of numbers R00 and C00. The route is the same as the previous route, and the previous guide data is used. Segment SGB is numbered R10 and C1
In addition to the route data of 0, guidance data is also included. this is,
This is because the traveling direction at the intersection C10 is different from the previous direction. The segment SGC is similarly route / guidance data. This portion is a route completely different from the previous route, and both route data and guidance data are required. The same applies to the segments SGD to SGE. Segment S
GF is the same route as the previous time, and the numbers R40 and C40
Only the route data. The same applies to the segment SGG.

(4) Data synthesis and route guidance ... Next,
With reference to FIG. 9, the operation of combining route / guidance data and route guidance on the vehicle side will be described. The data storage unit 1
03 stores route / guidance data obtained from the center side during the previous route search shown in FIG. Each vehicle receives the route / guidance data corresponding to its own ID from the center device 150 (step S20). The received route / guidance data is stored in the data storage unit 103. In the arithmetic processing unit 101, guidance data corresponding to the vehicle position measured by the position measuring unit 104 is stored in the data storage unit 103.
Is read from. Images and characters are displayed on the display unit 106.
And the sound is reproduced by the sound output unit 107. The user proceeds on the searched route while receiving the display and the voice guidance (step S21).

In this case, the arithmetic processing section 101 executes a data synthesizing program stored in the program storage section 102, and performs synthesizing processing according to the procedure shown in FIG. That is, it is determined for each segment whether or not the route data includes only the road number and the intersection number (step S23). If it is applicable (Y in step S23), the guidance data of the segment corresponding to the road number and the intersection number is read out from the already transmitted data in the data storage unit 103 and combined to provide guidance (step S24). . However, if it does not correspond (N in step S23), the guidance data obtained this time from the center side is read from the data storage unit 103 to provide guidance (step S25). The above operation is sequentially repeated for each segment by setting the counter (steps S22, S26, S27).

Referring to the example of FIG. 8 described above, the segment SGA is only the road number and the intersection number, that is, only the route data. Therefore, as indicated by the arrow FA, the guidance data DA from the previous route search is combined.
The guidance data DA includes display data indicating that the vehicle is going straight ahead at the intersection C00 and voice guidance data. As is clear from a comparison between FIG. 4 and FIG. 7, the intersection C00 is
In each case, it goes straight. For this reason, the previous guidance data held on the vehicle side is used for the current guidance as it is.

Next, in the segment SGB, as shown in FIG. 8, since route data and guidance data are transmitted from the center side, guidance is performed using the data. About the intersection C10, it went straight the previous time but turned left this time. For this reason, for the segment SGB, the previous guidance data is not used, and the guidance data newly extracted this time and transmitted from the center side is used. The same applies to the segments SGC to SGE.

Next, the segment SGF is only path data. For this reason, the guidance data DF is synthesized as indicated by the arrow FF. The guidance data DF includes "Intersection C
Display data and voice guidance data indicating "go straight on 40" are included. The intersection C40 goes straight in any case. For this reason, the previous guidance data held on the vehicle side is used for the current guidance as it is. The same applies to the segment SGG, and the guidance data DG is synthesized as indicated by the arrow FG.

As described above, according to this embodiment, on the vehicle side, the transmitted route guidance data transmitted and stored from the center side during the previous route search and the current route search data are used. The guidance is performed by combining the route guidance data transmitted from the center side. For this reason, by transmitting only necessary data that does not overlap, it is possible to reduce the amount of data transmitted from the center side to the mobile side, shorten the communication time, and reduce the communication cost. Further, since the data that has not been transmitted is synthesized on the vehicle side, the route guidance can be performed well even if the amount of data to be transmitted is reduced.

Further, since data is transmitted in segment units, which are the minimum units that can be guided, even if communication is interrupted halfway, for example, it is sufficient to transmit from the interrupted segment, and all data is transmitted. No need to resend. On the vehicle side, even if communication is interrupted on the way, guidance can be started based on the segment received on the vehicle side until the interruption. Data synthesis may be performed in segment units, which is convenient for synthesis processing.

[0042]

Second Embodiment Next, another embodiment will be described with reference to FIGS. In the above-described embodiment, regardless of whether transmitted data or already transmitted data is used, guidance using a map image, voice, or the like is provided for the entire route from the departure point to the destination of the searched route. However, when driving a car,
In most cases, the user does not always look at the display of the navigation device while driving, but refers to a key point on the route, such as an intersection that turns right or left. If the vehicle goes straight ahead even at an intersection, there is no need to refer to the navigation device. From such a viewpoint, if there is only data of important points such as intersections and junctions where the vehicle turns right and left, a navigation function can be performed. Further, by transmitting only necessary data from the center side to the mobile side, it is possible to further reduce the amount of data transmitted to the mobile side.

Therefore, in the present embodiment, the processing as shown in FIG. 10 is performed from step S3 in FIG. 6 described above. First, in the system control unit 152, an intersection on the searched route is an intersection (or a branch point) at which the course should be changed, such as a right or left turn, that is, a course change point (route guidance point, guidance point, guidance required point). , A route guidance intersection, a guidance intersection, or a guidance required intersection) (step S30). The course change point does not change the guide route itself. The determination of the course change point is made based on whether the vehicle enters or exits the intersection existing on the searched route along the road with a straight line or a gentle curve. For example, when the angle between the approach road and the exit road is equal to or smaller than a predetermined value, the intersection is determined to be a course change point.

FIG. 11 shows an example, and the solid line is the searched route. In FIG. 11, R1 to R9 represent road numbers, and C1 to C8 represent intersection numbers.
In this example, the intersections C3 and C6 correspond to the course change points. Since the intersections C1, C2, C4, C5, C7, and C8 are straight ahead, none of them corresponds to the course change point.

Next, the system control section 152 sets, for each course change point, a certain range including the change point as a peripheral area. For example, in the example of FIG. 11, a peripheral area A2 around an intersection C3 which is a course change point is set. A surrounding area A3 is set around the course change point C6. In the case where the vehicle goes straight on the road, no inconvenience occurs even if there is no map. However, at the turning point,
Since it is necessary to change the course such as turning left or right, it is necessary to display a map or landscape, or to provide voice guidance.
Therefore, for a certain range including a course change point, it is convenient to have detailed route guidance data. Therefore, such a peripheral area is set.

Next, a description will be given of a method of setting a peripheral area around a course change point. The peripheral area is set so as to be developed in an appropriate shape such as a circle or a rectangle in front of the approach road, for example, around the route change point. It does not have to be centered on the course change point, but it is sufficient to include it. When the peripheral area is set in a circular shape, the simplest method is to set the diameter d [Km] of the circle centering on the course change point. However, since the display section of the in-vehicle navigation device is usually rectangular, it is convenient to make the surrounding area rectangular.

When setting the peripheral area in this rectangular shape,
It is necessary to set the size n [km] × m [km] of each side of the rectangle and also set the direction. For example, FIG.
The surrounding area A2 for the course change point C3 shown in FIG.
m] × n [km] square. The value of n that determines the size of the peripheral area A2 is determined by the system controller 152.
May be set in advance in the program, or an arbitrary value may be set on the in-vehicle navigation device 100 and transmitted to the center device 150. In any case, the value of n is set in consideration of map matching as described later. In the case of n × m, m
Must be determined, for example, by setting n by a predetermined coefficient.

Next, an n × n rectangular range centered on the intersection C3, which is a course change point, is set from the value of n.
Then, the rectangular area is rotated around the intersection C3, and a peripheral area is set at an appropriate position. This setting, for example,
This is performed so that a straight line connecting the intersection C3 between the approach path to the intersection C3 and one side of the rectangular range and the intersection C3 is orthogonal to one side of the rectangular range. In other words, intersection C3
And the one side of the rectangular range is made orthogonal to the approach path to. Such a range setting takes into account that a map on the side of the on-vehicle navigation device, which will be described later, is displayed with a heading-up display on a rectangular screen.

In any one of the methods, the system control unit 152 selects the n × n diagonal positions (Xca3, YCa3),
(Xcb3, Ycb3) is determined, and is set as the peripheral area A2. Note that the diagonal positions (Xca3, YCa3), (X
Specific values of cb3, Ycb3) are represented by latitude and longitude.
The same applies to the peripheral area A3 of the intersection C6.

The surrounding area is set in advance for each combination of the approach road and the exit road at each intersection, and the corresponding guide data is stored in a database 1 in the form of a table.
53, and the corresponding guidance data may be read from this peripheral area table. In this case, there is an advantage that it is not necessary to perform an arithmetic process for setting the peripheral area.

If necessary, the starting point S and the destination G
, Peripheral areas A1 and A4 are respectively set. For example, when the departure place and the destination are both well known, guidance only around the course change point on the route on the way is sufficient. However, when it is not clear which direction the departure point S will proceed, it is convenient to have guidance data, and for the destination G, guidance data such as the presence or absence of a parking lot or various facilities around the destination G is also available. It is convenient if there is.

After the course change point and the surrounding area are set as described above, the processing from step S4 shown in FIG. 6 is performed. In this case, in step S9, as shown in parentheses, guidance data is extracted only for the surrounding area. In the above embodiment, guidance data for all routes is extracted, except for data that has already been transmitted. However, in the present embodiment, guidance data around the route change point excluding already transmitted data is extracted. On the vehicle side, the already transmitted guidance data is combined with the guidance data around the route change point, and detailed route guidance is performed around the route change point. That is, detailed display including a landmark or the like, or guidance by voice or the like is performed.

For routes other than the peripheral area, a simple display including an arrow mark MD indicating a traveling direction, a vehicle position mark ME, a background image MF, and a distance display MG is performed as shown in FIG. 12, for example. The arrow mark MD indicates the course change direction at the next course change point as viewed from the vehicle position. In the example of FIG. 11, since the vehicle turns right at the course change point C3, the arrow mark MD is directed rightward. The image data necessary for this display may be included in the route / guidance data and transmitted from the center device 150 to the in-vehicle navigation device 100, or may be transmitted to the in-vehicle navigation device 100.
May be stored in the data storage unit 103 in advance. Even with such a simple display, there is no particular inconvenience because the vehicle only needs to proceed along the road.

As described above, according to the present embodiment, the route change point and its surrounding area are extracted during the route search on the center side. The guidance data such as a map and a voice is sent to the vehicle only in the surrounding area except for the already transmitted guidance data. On the vehicle side, already transmitted guidance data is combined with the route / guidance data transmitted from the center side. Then, guidance is provided in detail for the peripheral area. For this reason, the amount of data transmitted from the center side to the vehicle side is further reduced, and the navigation device on the vehicle side is simplified, for example, by reducing the memory capacity. Further, even if the data amount is reduced, the route guidance is favorably performed.

The present invention has many embodiments, and can be variously modified based on the above disclosure. For example, the following is also included. (1) In the above-described embodiment, the transmitted data is stored on the center side, and whether or not transmission is necessary is determined by comparing the transmitted data with the current data. The data may be transmitted to the center, and the center may determine whether transmission is necessary based on the received data. In this case, the center does not need to hold the transmitted data of each vehicle.

(2) In the above embodiment, the data combining process is performed at the time of route guidance, but may be performed each time data of each segment is received, or may be performed after data of all segments is completely received. Is also good. (3) When transmitting data from the center to the vehicle, the number of segments of data included in the searched route may be transmitted to the vehicle in advance. By doing this,
Even if communication is interrupted in the middle, it is possible to determine from which segment retransmission is necessary.

(4) In the above-described embodiment, the data at the time of the previous route search is combined with the data of the current route search, but the guidance data before or twice before may be combined. Which one to use depends on the data storage capacity of the vehicle-side device. For some types of guidance data, data for all routes may be stored on the vehicle side. For example, landmark data,
CD-ROM for large data such as landscape data
If the data is stored in the vehicle using a DVD-ROM, the amount of data transmitted from the center to the vehicle can be further reduced.

(5) Guidance data for a certain area may be held on the vehicle side. For example, guidance data in the Kanto region is held on the vehicle side, and route / guidance data is obtained from the center side for other areas. (6) The road data, the intersection data, and the guidance data described in the above embodiment are merely examples, and may be appropriately changed as needed. In addition, the format of the data may be appropriately changed in the same manner. (7) In the above embodiment, the segment is a combination of a road and an intersection. However, any combination may be used as long as the unit can be guided. A segment may be composed only of road data or only intersection data. (8) The above-described embodiment is one in which the present invention is applied to a vehicle, but is applicable to various moving objects such as a portable mobile terminal.

[0059]

As described above, according to the present invention,
The following effects are obtained. (1) Since the data transmitted from the center side is combined with the data that has been transmitted in the past to provide guidance, only the necessary data that does not overlap is transmitted, so that the center side transmits the data to the mobile side. It is possible to reduce a data amount, a communication time, and a communication cost. Further, since route guidance is performed based on the combined data, route guidance can be performed well even if the amount of data to be transmitted is reduced.

(2) Since data is transmitted in the minimum unit that can be guided, even if communication is interrupted halfway, it is sufficient to transmit from the interrupted unit, and all data is transmitted again. No need. Further, the guidance can be started based on the unit received until the interruption of the communication.

(3) Since guidance is provided only for the area around the course change point on the search route, the amount of data transmitted from the center to the mobile side can be further reduced. In addition, since there is guidance data near the route change point, which is a main part on the search route, route guidance can be performed satisfactorily even if the amount of data transmitted to the mobile side is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of data stored in a database of FIG. 1;

FIG. 3 is a diagram showing an example of data contents constituting a segment.

FIG. 4 is a diagram illustrating an example of a searched route;

FIG. 5 is a diagram showing a route / guidance data file of the route shown in FIG. 4;

FIG. 6 is a flowchart showing an operation of route search and guidance data extraction on the center side.

FIG. 7 is a diagram showing an example of a route searched this time.

8 is a diagram showing a route / search data file when the previous route is set to FIG. 4 and the current route is set to FIG. 7;

FIG. 9 is a flowchart showing an operation of combining route / search data on the moving side.

FIG. 10 is a flowchart showing a main operation of the second embodiment.

FIG. 11 is a diagram showing an example of a course change point and a surrounding area in the second embodiment.

FIG. 12 is a diagram showing an example of guidance display of a route other than a peripheral area.

[Explanation of symbols]

 Reference Signs List 100 center device 100 navigation device 100 in-vehicle navigation device 101 arithmetic processing unit 102 program storage unit 103 data storage unit 104 position measurement unit 105 input unit 106 display unit 107 voice output unit 108 transmission / reception unit 150 center device 151 communication control unit 152 system control unit 153 database A1 to A4 peripheral area C1 to C8, C00 to C40 intersections DA, DF, DG ... guidance data G ... destination M ... intersection position MA ... ME ... mark MF ... background image MG ... distance display M201, M202 ... landmark R00-R50, R200, R201 ... road number S ... departure place SG1-SG6, SGA-SGG ... segment

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoki Ushiki 2--19-12 Sotokanda, Chiyoda-ku, Tokyo Inside Equos Research Co., Ltd. (72) Inventor Satoshi Kitano 2-19 Sotokanda, Chiyoda-ku, Tokyo No. 12 F-term in Equos Research Co., Ltd. (reference)

Claims (7)

[Claims] 1. A data storage means for storing data for route search and route guidance; a route search means for performing a route search using data in the data storage means; Data comparing means for comparing the route with the route to determine whether or not transmission of guidance data is required; guidance data obtaining means for obtaining guidance data requiring transmission from the data storage means based on the comparison result; and the route searching means A transmission unit for transmitting the route data obtained by the above and the guidance data obtained by the guidance data obtaining unit to a mobile side. 2. The navigation center device according to claim 1, wherein the guidance data acquisition unit acquires guidance data included in a peripheral area set at a course change point in the searched route. 3. A data receiving means for receiving data transmitted from the navigation center device according to claim 1 or 2; a data storage means for storing each data received thereby; A navigation device comprising: data synthesizing means for synthesizing data held by a side in advance; and route guidance means for performing route guidance based on the data thus synthesized. 4. The navigation device according to claim 3, wherein the data held by the mobile side in advance is already transmitted data transmitted from the navigation center device according to claim 1 or 2. 5. A navigation system comprising the navigation center device according to claim 1 or 2 and the navigation device according to claim 3 or 4. 6. The navigation system according to claim 5, wherein the data is transmitted and received in units of a guideable segment. 7. A step of searching for a route on the center side; a step of comparing the searched route with a route that has already been transmitted to determine whether transmission is necessary; and performing transmission based on the comparison result. Obtaining the required guidance data; transmitting the searched route data and the guidance data to the mobile side;
A navigation method, comprising: combining data previously stored on the moving side; and performing route guidance based on the combined data.