JP4026250B2 - Navigation system and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is suitable for a system that provides data necessary for route guidance from the center side to the moving side. Na The present invention relates to a navigation system and method.
[0002]
[Background]
In a navigation system that is generally widespread, a navigation device is mounted for each moving body, for example, a vehicle, and route guidance is performed using map data stored in a CD-ROM or the like for each vehicle. ing. However, in such a system, it is necessary to constantly purchase new CD-ROMs corresponding to new construction or abolition of roads. Further, if the type of media is different as in a DVD-ROM or the format is different even if the type is the same, the navigation device itself must be replaced.
[0003]
On the other hand, Japanese Patent Laid-Open No. 10-19588 discloses a navigation system that transmits map images and optimum route data necessary for guiding a vehicle to a destination from the center (base) side to the vehicle side. It is disclosed. According to this system, communication is performed between the data transmission system on the center side and the vehicle navigation apparatus on the moving side. The data transmission system has a database that stores data necessary for guiding a vehicle to a destination. The data transmission system reads out necessary data from a database based on a request from a vehicle navigation device and creates a map image. In addition, route search is performed to create optimum route data. The created map image and optimum route data are transmitted to the vehicle side. In the vehicle navigation apparatus, corresponding display is performed based on the map image and the data of the optimum route transmitted from the system side.
[0004]
[Problems to be solved by the invention]
By the way, 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 moving side in response to a request for route guidance. Thereby, on the moving side, the map image corresponding to the traveling position is sequentially displayed on the display of the navigation device from the departure to the arrival at the destination.
[0005]
However, for example, when the vehicle travels in the reverse direction and returns from the destination to the departure point, the travel is made in the reverse direction unless there are special circumstances such as one-way traffic or road construction. In this case, the route searched on the center side is the same on the forward route and the return route, and the guidance data is considered to be substantially the same. Alternatively, a case where the current search route partially overlaps with the previous search route may be considered.
[0006]
However, in the background art described above, route data and guidance data are transmitted from the center side to the moving side each time a route search is performed. 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 a lot of waste, and communication time and communication cost are increased more than necessary.
[0007]
The present invention focuses on the above points, and its purpose is to transmit only necessary data that does not overlap, thereby reducing the amount of data transmitted from the center side to the mobile side, shortening the communication time, and reducing the communication cost. It is to reduce. Another object is to provide good route guidance even if the amount of data transmitted to the mobile side is reduced.
[0008]
[Means for Solving the Problems]
To achieve the object, the navigation of the present invention. system Is A navigation system comprising a center device and a navigation device on the moving side, the center device comprising: Data storage means for storing data for route search and route guidance, and route search is performed using data in this data storage means. Route data Route search means; Said Route data And already sent routes data And For each segment that can be guided Data comparison means for comparing and determining whether or not to transmit guide data; The data comparison means Based on the result of the comparison, the guidance data acquisition means for obtaining the guidance data that needs to be transmitted from the data storage means; the route data obtained by the route search means and the guidance data obtained by the guidance data acquisition means Transmitting means for transmitting to; The navigation device includes: data receiving means for receiving route data and guidance data transmitted from the center device; data storage means for storing data received thereby; and the received data is route data. A judging means for judging whether or not only for each segment; a synthesis means for synthesizing the received route data and guide data held in advance on the moving side when the judging means judges only the route data; Segments determined as only route data by the determining means perform route guidance based on the data combined by the combining means, and segments determined not only as route data by the determining means are received route data and guidance data. Route guidance means for performing route guidance based on It is provided with.
[0009]
According to one of the main forms, the guidance data acquisition means acquires the guidance data included in the peripheral area set as the course change point in the searched route. It is characterized by that.
[0010]
According to another aspect, the guide data held in advance by the moving side is already transmitted data transmitted from the center device. Still other forms Is the data Said It is characterized by transmitting and receiving in units of segments.
[0011]
The navigation method of the present invention is Using data storage means storing route search and route guidance data, Searching for a route; a route searched by this data And already sent routes data The For each segment that can be guided Compared to, Guidance data A step of determining whether transmission is necessary; based on the comparison result, guidance data that needs to be transmitted From the data storage means Obtaining the searched route data and the guidance data to the mobile side; A step of determining for each segment whether or not the received data is only route data on the mobile side; Data and previously stored on the moving side guide Combining with data; Segments that are determined to be only route data by the above determination are Route guidance based on the combined data A segment that is determined not only to be route data by the above determination performs route guidance based on the received route data and guidance data. A step including: 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]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail. In the following embodiments, a case where a vehicle is assumed as the moving side and the present invention is applied to an in-vehicle navigation device will be described as an example.
[0013]
First, the outline of the following embodiment will be described. On the vehicle side, search basic data indicating the starting point and destination of 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 side. As a result, for the previous route that has already been transmitted, the guidance data exists on the vehicle side, so that the guidance data is extracted for the other route. Then, route data and guidance data not 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 side and the corresponding portion of the route / guidance data obtained from the previous center side are combined. Based on the combined route / guidance data, map display and voice guidance are performed.
[0014]
Embodiment 1
(1) Overall Configuration First, the overall configuration of the first embodiment will be described with reference to FIG. FIG. 1 shows a configuration of a navigation system according to the present embodiment. The navigation system of this embodiment is configured by a center device 150 on the center side and an in-vehicle navigation device 100 on the moving side.
[0015]
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 is used for transmitting / receiving data to / from the navigation device 100. A communication system such as a car phone, a mobile phone, or a PHS may be used. The system control unit 152 includes an arithmetic processing unit that includes a CPU and a memory. The memory contains
(1) A route search program for searching for a route from the designated departure point to the destination,
(2) A program for extracting guidance data on the searched route,
(3) A program that compares the searched route with the previous time and this time,
For example, various programs executed by the center device 150 are stored. The memory also has a working area used for executing these programs.
[0016]
The database 153 is a large-capacity storage medium such as a hard disk. The route search includes route data (road number and intersection number) representing a route, search data used for route search, and guidance data for guiding the searched route. And data necessary for route guidance are stored. Specific contents are as follows, for example.
(1) Map data: Data for displaying a map on the display of the navigation device.
(2) Road data: As shown in FIG. 2 (A), road number string, node point number and position (longitude / latitude) set on each road, road name, road type, road length, drawing data Etc. The road drawing data may be vector data composed of a plurality of drawing coordinates, or may be bitmap image data.
(3) Intersection data: As shown in FIG. 2 (B), intersection number string, intersection name, position (longitude / latitude), guidance voice for instructing the course change direction of the intersection, so-called land that serves as a guide mark Data such as marks and landscapes of major buildings. The intersection includes a branch point.
(4) Search data: Data for specifying the position (longitude and latitude) of the destination from the telephone number, address, name and the like.
(5) Previous route data: As shown in FIG. 2 (C), this is route data obtained at the previous route search of each vehicle. This route data is held together with the vehicle ID.
[0017]
Next, the in-vehicle navigation device 100 will be described. The arithmetic processing unit 101 is configured mainly with a CPU. The program storage unit 102
(1) A program for combining the route / guide data transmitted from the center apparatus 100 (there may be only route data) and the corresponding portion of the previous route / guide data,
(2) A program for displaying a route on the display unit 106 based on the route / guidance data,
(3) A program for outputting guidance voice from the voice output unit 107,
For example, a memory for storing a program executed by the arithmetic processing unit 101.
[0018]
The data storage unit 103 functions as a working area that is appropriately used when executing the program, and stores, for example, the following data.
(1) Route / guide data transmitted from the center device 150,
(2) ID data unique to the vehicle,
(3) Vehicle position data (longitude / latitude) measured by the position measurement unit 104,
[0019]
Among these, the vehicle position data (3) includes a plurality of past position data in addition to the current position data measured by the position measurement unit 104 at predetermined time intervals. For example, position data of measurement points included in a certain distance or position data of a certain number of measurement points is stored. When the position measurement unit 104 newly performs measurement, the latest position data is stored, and the oldest stored position data is deleted. By connecting the plurality of position data, a travel locus of the vehicle can be obtained. This travel locus is used for so-called map matching for specifying the road on which the vehicle is traveling.
[0020]
Next, the position measuring unit 104 is for measuring the position of the vehicle using so-called GPS, D-GPS, etc., and receives signals from a plurality of GPS satellites to measure the absolute position of the vehicle. It has a receiver, a speed sensor and a direction sensor for measuring the relative position of the vehicle. Speed sensors and azimuth sensors are used for autonomous navigation. The relative position measured by these sensors is used to obtain the position in a tunnel where the GPS receiver cannot receive radio waves from the satellite, or to correct the positioning error of the absolute position measured by the GPS receiver. .
[0021]
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. On the touch panel, when a user touches an icon or the like displayed on the display unit 106 with a finger, corresponding data and commands are input. In a data input device using voice recognition, corresponding data and commands are input when a user utters a voice.
[0022]
The display unit 106 is a display using liquid crystal, CRT, or the like, and includes a touch panel as described above. The transmission / reception unit 108 is a communication device for transmitting / receiving data to / from the center device 150 side, and includes a modem. A system such as a car phone, a mobile phone, or a PHS may be used.
[0023]
(2) Data segment: Next, the mode of data handled in this embodiment will be described. Route data and guidance data are transmitted and received between the center side and the vehicle side. In this embodiment, data is exchanged 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.
[0024]
For example, as shown in FIG. 3, the segment is represented by a combination of a road number R200 and an end point intersection number C2. And this segment data includes
(1) Road data: road name, road length, road type, road drawing, and other data relating to the road of road number R200 (see FIG. 2 (A)),
(2) Intersection data: Name of the intersection with the intersection number C2, the attribute of the intersection, the position of the intersection, so-called landmarks M201 and M202 near the intersection, roads R201 and R202 to be connected, voice guidance, and other data (FIG. 2 (B )reference),
Is included.
[0025]
For example, it is assumed that the searched route is a route as shown in FIG. In the figure, a bold line is a searched route, and roads and intersections of numbers R00, C00, R10, C10, R20, C20, R30, C30, R40, C40, R50 are on the route from the departure point S to the destination G. Exist in order. For example, roads R01 and R02 are connected to the intersection C00, and a road R11 is connected to the intersection C10. The same applies to other intersections. The route / guidance data file in such a case is as shown in FIG. Of these, the segment SG1 is a combination of route data and guidance data relating to roads and intersections with numbers R00 and C00. A segment SG2 is a combination of route data and guidance data regarding roads and intersections of numbers R10 and C10. The same applies hereinafter. The last segment SG6 is only data relating to the road number R50.
[0026]
(3) Route Search and Guidance Data Extraction Next, route search and guidance data extraction operations will be described with reference to the flowchart of FIG. In the in-vehicle navigation device 100, first, 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 user of the in-vehicle navigation device 100 uses the input unit 105 to input the facility name, telephone number, or address of the destination. Then, the vehicle current position is transmitted to the center apparatus 150 together with the vehicle ID as the departure point data and the destination telephone number and address as the destination data.
[0027]
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 152 determines a starting point and a destination based on the received data. First, as the starting point of the route search, based on the current position data of the vehicle transmitted from the in-vehicle navigation device 100, the current position of the vehicle or an intersection near it is set. On the other hand, for the destination, the database 153 is referred to, and the location of the facility corresponding to the telephone number or address transmitted from the in-vehicle navigation device 100 is read from the database 153. Then, the read facility location or an intersection near the facility location is set as a route search destination (step S2).
[0028]
In the center device 150, a route search is performed based on the starting point and the destination determined as described above (step S3). That is, the system control unit 152 executes a route search program based on the departure point and destination data, and searches for a recommended route from the set departure point to the destination. As a route search method, for example, the distance from the departure point to the destination is the shortest, the travel time is the shortest, the transit point is taken into account, the traffic congestion data obtained from VICS, etc. and the road construction data are taken into account. Various methods are known, such as. The searched route is, for example, as shown in FIG. The searched route data is stored in the database 153.
[0029]
Next, the center device 150 compares the route searched as described above with the route searched during the previous route search. That is, the route data already transmitted corresponding to the ID of the corresponding vehicle is referred to, and it is determined whether or not the guidance data on the current searched route has already been transmitted to the vehicle (step S5, S5). S6). This determination is made for all segments by setting a counter representing the number of segments (steps S4, S10, S11).
[0030]
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 road data and intersection route data included in the segment is set to “ON” ( Step S7). Conversely, when the guidance data of the i-th segment is new that has not been transmitted (N in step S6), the segment transmission flag for transmitting the route and guidance data included in the segment is “ON”. (Step S8). Then, guidance data corresponding to the segment is extracted from the database 153 (step S9). The parentheses in step S9 will be described later.
[0031]
The route / guidance data of the segment whose segment transmission flag is “ON” and the route data of the segment whose number transmission flag is “ON” obtained in the above manner correspond to the route order (the order used on the vehicle side). Is transmitted to the vehicle-mounted navigation device 100 of the vehicle having the ID (step S12). The transmitted data is stored in the data storage unit 103. On the other hand, the route data is stored in the system control unit 152 of the center device 150 together with the ID of the corresponding vehicle. Such route search, extraction of guidance data, and transmission thereof are performed by the center device 150 in response to the request of each vehicle.
[0032]
For example, it is assumed that the route as shown in FIG. 4 is searched at the previous route guidance and the route / guidance data of the corresponding segment is transmitted to the vehicle side. Then, it is assumed that the route at the time of this route search is a route as indicated by a thick line in FIG. Due to circumstances such as road construction, lane restrictions, differences in waypoints, search conditions such as time priority and distance priority, the route in the middle may be different while the starting point and destination are the same as illustrated. Comparing the two, the previous time progressed in the order of C10 → R20 → C20 → R30 → C30, but this time, the process progressed in the order of C10 → R11 → C70 → R80 → C80 → R31 → C30. Therefore, the guidance data has already been transmitted to the vehicle side from the departure point S to the intersection C00 and from the road R40 to the destination G.
[0033]
So, in this form,
(1) For the segment including the route from the starting point S to the intersection C00 and the segment including the route R40 to the destination G, which are the routes common to the previous time and the current time, the route data, that is, the road number indicating the route and the intersection number Only data is sent.
(2) Route data and guidance data are transmitted for segments including C10 to C30 which are different routes from the previous time and this time.
[0034]
As a result, the current route / guide data file is as shown in FIG. First, the coordinates of the starting point and destination are at the top of the file. Next, the segment SGA is only the route data of the numbers R00 and C00. The route is the same as the previous route, and the previous guide data is used. The segment SGB includes guidance data in addition to the route data of the numbers R10 and C10. This is because the traveling direction at the intersection C10 is different from the previous time. Similarly, the segment SGC is route / guide data. This part is completely different from the previous route, and both route data and guidance data are required. The same applies to the segments SGD to SGE. The segment SGF is the same route as the previous time, and is only the route data of the numbers R40 and C40. The same applies to the segment SGG.
[0035]
(4) Combining Data and Route Guidance Next, with reference to FIG. 9, the composition of route / guide data and route guidance on the vehicle side will be described. The data storage unit 103 stores route / guidance data obtained from the center at the time of the previous route search shown in FIG. Each vehicle receives route / guide data corresponding to its own ID from the center device 150 (step S20). The received route / guide 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 read from the data storage unit 103. Images and characters are displayed on the display unit 106, and audio is reproduced by the audio output unit 107. The user proceeds on the searched route while receiving these displays and voice guidance (step S21).
[0036]
In this case, the arithmetic processing unit 101 executes a data synthesis program stored in the program storage unit 102, and performs synthesis processing according to the procedure shown in FIG. That is, for each segment, it is determined whether or not the route data includes only road numbers and intersection numbers (step S23). Then, if applicable (Y in step S23), the guidance data of the segment corresponding to the road number and the intersection number is read from the already transmitted data in the data storage unit 103 and synthesized to provide guidance (step S24). . However, if not applicable (N in step S23), the guidance data obtained from the current center side is read from the data storage unit 103 and guidance is provided (step S25). The above operation is sequentially repeated for each segment by setting the counter (steps S22, S26, S27).
[0037]
In the example of FIG. 8 described above, the segment SGA is only a road number and an intersection number, that is, only route data. For this reason, as indicated by the arrow FA, the guidance data DA for the previous route search is synthesized. The guidance data DA includes display data and voice guidance data indicating “go straight on the intersection C00”. As is clear from the comparison between FIGS. 4 and 7, the intersection C00 is straight ahead in both cases. Therefore, the previous guidance data held on the vehicle side is used as it is for the current guidance.
[0038]
Next, as shown in FIG. 8, in the segment SGB, route data and guidance data are transmitted from the center side, and guidance is performed using the route data and guidance data. As for the intersection C10, the vehicle travels straight ahead last time, but turns left this time. For this reason, the previous guidance data is not used for the segment SGB, but the guidance data newly extracted this time and transmitted from the center side is used. The same applies to the segments SGC to SGE.
[0039]
Next, the segment SGF is only route data. For this reason, the guidance data DF is synthesized as indicated by the arrow FF. The guidance data DF includes display data and voice guidance data indicating “go straight on the intersection C40”. The intersection C40 goes straight in both cases. Therefore, the previous guidance data held on the vehicle side is used as it is for the current guidance. The same applies to the segment SGG, and the guidance data DG is synthesized as indicated by the arrow FG.
[0040]
As described above, according to the present embodiment, on the vehicle side, the route guidance data already transmitted and stored from the center side during the previous route search and stored from the center side in the current route search are stored. The route guidance is synthesized by combining the transmitted route guidance data. For this reason, by transmitting only the 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. In addition, since the data that has not been transmitted is synthesized on the vehicle side, route guidance can be performed well even if the amount of data to be transmitted is reduced.
[0041]
In addition, since the data is transmitted in segment units, which is the smallest unit that can be guided, even if communication is interrupted in the middle, for example, it is only necessary to transmit from the interrupted segment and retransmit all data. There is no need. On the vehicle side, even if communication is interrupted in the middle, guidance can be started based on the segments received on the vehicle side before the interruption. Data synthesis may be performed in segment units, which is convenient for synthesis processing.
[0042]
Embodiment 2
Next, another embodiment will be described with reference to FIGS. 10 and 11. In the above-described embodiment, regardless of whether transmitted data or already transmitted data is used, guidance from the starting point to the destination of the searched route is provided by a map image, voice, or the like. However, a driver who is driving a car does not always look at the display of the navigation device while driving, but often refers to a point on a route such as an intersection that turns right or left. If the vehicle goes straight even at an intersection, it is not necessary to refer to the navigation device. From this point of view, if there is only data on important points that require guidance, such as intersections and turning points that turn right and left, the navigation function can be achieved. In addition, if only necessary data is sent from the center side to the moving side in this way, the amount of data transmitted to the moving side can be further reduced.
[0043]
Therefore, in this embodiment, the processing as shown in FIG. 10 is performed after step S3 in FIG. 6 described above. First, in the system control unit 152, the intersection on the searched route is an intersection (or a branch point) whose route should be changed, such as a left or right turn, that is, a route change point (route guidance point, guidance point, guidance necessary point). Or a route guidance intersection, a guidance intersection, or a guidance-necessary 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 or not the intersection existing on the searched route enters or exits along the road in a straight line or a gentle curve. For example, when the angle between the approach path and the exit path is equal to or less than a predetermined value, the intersection is determined to be a course change point.
[0044]
An example is shown in FIG. 11, and a solid line is a searched route. In FIG. 11, R1 to R9 represent road numbers, and C1 to C8 represent intersection numbers. In this example, intersections C3 and C6 correspond to course changing points. Since the intersections C1, C2, C4, C5, C7, and C8 are straight ahead, none of them corresponds to a course change point.
[0045]
Next, the system control unit 152 sets a certain range including each course change point as a peripheral area. For example, in the example of FIG. 11, a peripheral area A2 centering on an intersection C3 that is a course change point is set. A peripheral area A3 is set around the route change point C6. If the vehicle goes straight on the road, there will be no inconvenience even if there is no map. However, at the course change point, the course must be changed, such as turning left or right, so it is necessary to display a map or a landscape or to provide guidance by voice. Therefore, it is convenient to have detailed route guidance data for a certain range including the route change point. Therefore, such a peripheral region is set.
[0046]
Next, a method for setting a peripheral area centered on a course change point will be described. The peripheral area is set so as to develop into an appropriate shape such as a circle or a rectangle in front of the approach path, for example, with the course changing point as the center. Even if it is not centered on the course change point, it is sufficient to include it. When the peripheral area is set in a circular shape, the diameter d [Km] of the circle centering on the course change point may be set most simply. However, since the display unit of the in-vehicle navigation device is usually rectangular, it is convenient if the peripheral area is also rectangular.
[0047]
When the peripheral area is set 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 thereof. For example, the peripheral area A2 with respect to the course change point C3 shown in FIG. 11 is a square of [n] [km] × n [km]. The value of n that determines the width of the peripheral area A2 may be set in advance in the program of the system control unit 152, or an arbitrary value is set on the in-vehicle navigation device 100 side and the center device 150 side You may make it transmit to. In any case, the value of n is set in consideration of the map matching viewpoint as will be described later. In the case of n × m, it is necessary to determine the value of m, but for example, it is set by multiplying n by a predetermined coefficient.
[0048]
Next, an n × n rectangular range centering 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 is performed so that, for example, a straight line connecting the intersection position M 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, the approach path with respect to the intersection C3 and one side of the rectangular range are orthogonalized. Such a range setting takes into account that a map on the side of the in-vehicle navigation device to be described later is displayed in a heading-up manner on a rectangular screen.
[0049]
In the system control unit 152, n × n diagonal positions (Xca3, YCa3), (Xcb3, Ycb3) of the rectangular range are determined by any method and set as the peripheral area A2. The specific values of the diagonal positions (Xca3, YCa3), (Xcb3, Ycb3) are represented by longitude and latitude. The same applies to the peripheral area A3 of the intersection C6.
[0050]
In addition, a peripheral area is set in advance for each combination of an approach path and an exit path at each intersection, and corresponding guide data is prepared in the database 153 in the form of a table, and the corresponding guide data is obtained from this peripheral area table. May be read out. In this way, there is an advantage that it is not necessary to perform arithmetic processing for setting the peripheral area.
[0051]
Further, if necessary, peripheral areas A1 and A4 are also set around the departure point S and the destination G, respectively. For example, when both the starting point and the destination are well known, it is sufficient to provide guidance only in the vicinity of the route change point on the route. However, for the departure point S, it is convenient to have guidance data when it is unknown in which direction it will travel, and for destination G, there is guidance data such as the presence of parking lots and various facilities around it. It is convenient if there is.
[0052]
After the course change point and its surrounding area are set as described above, the processes after step S4 shown in FIG. 6 are performed. In this case, in step S9, as shown in parentheses, guidance data is extracted only for the peripheral area. In the above form, the guide data for all routes is extracted, although the already transmitted data is excluded. However, in this embodiment, data obtained by removing already transmitted data from the guidance data around the route change point is extracted. On the vehicle side, already transmitted guidance data is synthesized 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 landmarks and guidance by voice are performed.
[0053]
For a route other than the peripheral region, for example, as shown in FIG. 12, 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. The arrow mark MD indicates the course change direction at the next course change point as seen from the vehicle position. In the example of FIG. 11, since the right turn is made at the course change point C3, the arrow mark MD is directed to the right. 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 stored in the data storage unit 103 in advance by the in-vehicle navigation device 100. It may be. Even with such a simple display, there is no particular inconvenience because the vehicle only needs to travel along the road.
[0054]
Thus, according to the present embodiment, the route change point and its surrounding area are extracted during the route search on the center side. And about guidance data, such as a map and an audio | voice, only the surrounding area is sent to the vehicle side except the already transmitted guidance data. On the vehicle side, already transmitted guidance data is combined with the route / guidance data sent 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 such as a reduction in memory capacity. Even if the amount of data is reduced, route guidance is performed well.
[0055]
The present invention has many embodiments, and various modifications can be made based on the above disclosure. For example, the following are included.
(1) In the above-described embodiment, the transmitted data is stored on the center side, and this data is compared with the current data to determine whether transmission is necessary or not. Data may be transmitted to the center side, and the center side may determine whether transmission is necessary based on the received data. In this case, the center side does not need to have already transmitted data of each vehicle.
[0056]
(2) In the above embodiment, the data combining process is performed at the time of route guidance. However, it may be performed every time data of each segment is received, or may be performed after reception of data of all segments is completed.
(3) When data is transmitted from the center side to the vehicle side, the number of data segments included in the searched route may be transmitted to the vehicle side in advance. In this way, it is possible to determine from which segment retransmission is necessary even if communication is interrupted in the middle.
[0057]
(4) In the above embodiment, the previous route search data is combined with the current route search data. However, the previous guidance data may be combined with the previous route search data. Which of these is related to the data storage capacity of the vehicle side device. For some types of guidance data, data on all routes may be held on the vehicle side. For example, if a large amount of data such as landmark data or landscape data is held on the vehicle side by a CD-ROM or DVD-ROM, the amount of data transmitted from the center side to the vehicle side can be further reduced. It becomes possible.
[0058]
(5) You may make it hold | maintain the guidance data of a fixed area on the vehicle side. For example, the Kanto region guidance data is held on the vehicle side, and the route / guidance data is obtained from the center side for other regions.
(6) The road data, the intersection data, and the guidance data shown in the above embodiment are examples, and may be appropriately changed as necessary. Further, the format of the data may be changed as appropriate.
(7) In the said form, although the segment was set as the combination of a road and an intersection, as long as it is a unit which can be guided, it is good as an appropriate combination. A segment may be composed of only road data or intersection data.
(8) Although the said form applies this invention to a vehicle, it is applicable to various mobile bodies, such as a portable mobile terminal.
[0059]
【The invention's effect】
As described above, the present invention has the following effects.
(1) Since the past transmitted data is combined with the data transmitted from the center side for guidance, only necessary data that does not overlap is transmitted from the center side to the mobile side. It is possible to reduce the data amount, the communication time, and the communication cost. Further, since route guidance is performed based on the combined data, route guidance can be performed satisfactorily even if the amount of data to be transmitted is reduced.
[0060]
(2) Since data is transmitted in the smallest unit that can be guided, even if communication is interrupted, it is only necessary to transmit from the interrupted unit, and there is no need to retransmit all data. . Moreover, guidance can be started based on the unit received until communication is interrupted.
[0061]
(3) Since guidance is provided only for the area around the route change point on the searched route, the amount of data transmitted from the center side to the moving side can be further reduced. In addition, since guidance data exists in the vicinity of a route change point that is a main part on the searched route, route guidance can be performed satisfactorily even if the amount of data transmitted to the moving side is reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration in Embodiment 1 of the present invention.
FIG. 2 is a diagram illustrating an example of data stored in the 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.
5 is a view showing a route / guide data file of the route shown in FIG. 4; FIG.
FIG. 6 is a flowchart showing operations 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 shown in FIG. 4 and the current route is shown in FIG. 7. FIG.
FIG. 9 is a flowchart showing an operation of combining route / search data on the moving side.
FIG. 10 is a flowchart showing main operations of the second embodiment.
FIG. 11 is a diagram illustrating an example of a course change point and a peripheral area in the second embodiment.
FIG. 12 is a diagram illustrating an example of guidance display for routes other than the surrounding area.
[Explanation of symbols]
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 measuring unit
105 ... Input unit
106 ... Display section
107: Audio output unit
108: Transmitter / receiver
150 ... Center device
151. Communication control unit
152 ... System control unit
153 ... Database
A1 to A4 ... Peripheral area
C1 to C8, C00 to C40 ... intersection
DA, DF, DG …… Guidance data
G ... Destination
M ... Intersection
MA-ME ... mark
MF ... Background image
MG ... Distance display
M201, M202 ... Landmark
R00 to R50, R200, R201 ... road number
S ... Departure location
SG1 to SG6, SGA to SGG ... segment

Claims (5)

A navigation system composed of a center device and a navigation device on the moving side,
The center device is
Data storage means for storing data for route search and route guidance;
Route search means for obtaining a row have route data a route search by using the data of the data storage means;
Compared to each possible guide segment and the path data and the already-transmitted route data, data comparing means for determining the necessity of the transmission of presentation data;
Guidance data acquisition means for obtaining, from the data storage means, guidance data that requires transmission based on the comparison result by the data comparison means;
A 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 the moving side;
With
The navigation device
Data receiving means for receiving route data and guidance data transmitted from the center device;
Data storage means for storing the data received thereby;
Determining means for determining for each segment whether or not the received data is only path data;
A combining unit configured to combine the received route data with the guidance data held in advance by the moving side when the determination unit determines that only the route data exists;
Segments determined as only route data by the determining means perform route guidance based on the data combined by the combining means, and segments determined not only as route data by the determining means are received route data and guidance. Route guidance means for performing route guidance based on data;
A navigation system characterized by comprising: The navigation system according to claim 1, wherein the guidance data acquisition unit acquires guidance data included in a peripheral area set as a course change point in the searched route. The navigation system according to claim 1 or 2, wherein the guide data held in advance by the moving side is already transmitted data transmitted from the center device. The navigation system according to any one of claims 1 to 3, characterized in that transmitting and receiving the data, the segment as a unit. Searching for a route on the center side using a data storage means storing route search and route guidance data ;
Comparing the searched route data with the already transmitted route data for each guideable segment to determine whether or not the guide data needs to be transmitted;
Obtaining guide data that needs to be transmitted from the data storage means on the basis of the comparison result thereby;
Transmitting the searched route data and the guidance data to the moving side;
Determining, on a mobile side, for each segment whether the received data is only route data;
A step of synthesizing the received route data with the guidance data held in advance on the moving side when it is determined that only the route data is present;
The segment is determined only route data by determination have line route guidance based on the data after combined by the step, the route data and guidance data the segment determined to not only the route data by judgment of the received cormorants line the route guidance based on the step;
A navigation method comprising:

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