JP4239327B2 - Navigation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention provides data necessary for route guidance from the center side.In-vehicle deviceNavigation method suitable for providing divided into two sidesTo the lawIt is related.
[0002]
[Prior art]
  Conventionally, as a system for providing route data and guidance data from the center side to the moving side, there is a “navigation system” disclosed in, for example, Japanese Patent Application Laid-Open No. 10-19588. This navigation system is configured to transmit map images and route data necessary for guiding a vehicle (user) to a destination from the navigation information transmission system (center side) to the vehicle side (moving side). Yes.
[0003]
  According to this navigation system, in the navigation information transmission system, necessary data is read out from various databases based on each request issued from the vehicle-side navigation device, and transmitted to the navigation device, or issued from the vehicle-side navigation device. The route search result performed based on the route search request is transmitted to the navigation device. On the other hand, in the navigation device, a map image created from the received predetermined data and the searched optimum route are displayed on a display unit such as a CRT to guide the user to the destination.
[0004]
  Japanese Patent Laid-Open No. 8-334374 discloses an “on-vehicle route guidance device” that transmits the latest recommended route from the center side to the vehicle side when the vehicle deviates from the recommended route due to a driving operation error. ing. According to this system, the vehicle transmits a starting point and a destination to the control center as necessary, and receives a recommended route. It is determined whether or not the vehicle is traveling on the recommended route. If the vehicle deviates from the recommended route, the departure point is set again and transmitted to the control center together with the destination. The information center searches for the route from the reset starting point to the destination received from the vehicle, and transmits the data of the searched recommended route to the vehicle.
[0005]
[Problems to be solved by the invention]
  By the way, when the vehicle is traveling in a tunnel or mountainous area where radio waves or other communication means do not reach, or in areas where the radio waves are weak, such as shadows of buildings (hereinafter referred to as “radiation insensitive areas”). May not be able to communicate well with the center side and may not be able to acquire necessary route / guide data. The technology disclosed in each of the above-mentioned publications does not consider such a radio wave situation and has a disadvantage that it cannot receive route guidance with peace of mind.
[0006]
  The present invention focuses on the above points, and a highly reliable navigation method that can confirm the current position of the vehicle regardless of the communication status.The lawThe purpose is to provide.
[0007]
[Means for Solving the Problems]
  To achieve the above objective,Claim1In this navigation method, drawing data and guidance data for guiding the route from the starting position of the vehicle to the destination are divided and sent from the center side to the in-vehicle device side, and route guidance is performed on the in-vehicle device side based on the data. The drawing method and the guidance data for guiding the divided route are transmitted from the center side to the in-vehicle apparatus side at different geographical positions or at different times, and The side determines the communication status of the specific position where the data is expected to be transmitted, and when it is determined that the communication status of the specific position is poor communication or communication is impossible, all route drawing data for drawing the entire route Is a technical feature.
[0008]
  Claim1In the described invention, the drawing data and the guidance data transmitted from the center side to the in-vehicle device side are transmitted corresponding to different geographical positions or different times on the in-vehicle device side, and by the communication status determination on the center side If it is determined that the communication status at a specific position where these data are expected to be transmitted is communication failure or the like, all route drawing data is transmitted to the in-vehicle device side. Thereby, the in-vehicle device side can receive all route drawing data when the center side determines that the communication status at the specific position is communication failure or the like by the communication status determination.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the navigation method of the present inventionLegalEmbodimentAnd reference examplesWill be described with reference to FIGS. A navigation system according to an embodiment of the present invention includes an information center (center side) that divides and transmits route / guidance data for route search from a starting position of a vehicle to a destination, and receives the transmitted divided data. And an in-vehicle device (on-vehicle device side) that provides route guidance to the user based on the divided data.
[0010]
  As shown in FIG. 1, the information center 10 mainly includes a transmission / reception unit 12, a calculation processing unit 14, a database 30, and an external information collection unit 40.
  The transmission / reception unit 12 is a wireless communication device including a transmission device and a reception device, and is used to transmit and receive data to and from the in-vehicle device 100 via a wireless line. For example, a wireless communication system such as a car phone, a mobile phone, or a PHS is used, and the communication form thereof is, for example, a packet communication method.
[0011]
  The arithmetic processing unit 14 includes a CPU 16 that performs arithmetic processing and a memory 18 that stores various programs and data.
  The memory 18 includes a route search program 20 for searching for a route from the current position (departure position) of the vehicle to the destination, a segment processing program 22 for setting a segment length of the searched route and a road length to be transmitted to the vehicle side, A guidance data extraction program 24 that searches, extracts and edits guidance data corresponding to the set road length, a communication determination program 25 that determines the suitability of data transmission, a system control program 26 that controls and manages the overall operation, etc. Various programs executed in the information center 10 are stored. The memory 18 also has a predetermined work area used for executing these programs.
[0012]
  The database 30 includes route search data 32 for searching for a recommended route, guidance data 34 for storing route guidance data, communication area data 36 for storing data related to a communication area, and a telephone number and address for setting a destination. Data necessary for route search and route guidance such as destination setting data 38 is stored. The route search data 32 includes data regarding intersections, data regarding roads, data regarding node points, and the like. The guidance data 34 includes various guidance data such as map data of each intersection and road, landmark data indicating major facilities, and voice guidance data. The communication area data 36 includes data related to the communication status that is previously grasped on the information center 10 side, such as an insensitive zone of radio waves, a zone inadequate for communication even when radio waves arrive, and the like.
[0013]
  Furthermore, an external information collection unit 40 is connected to the database 30. This external information collection unit 40 collects the latest road / traffic information and communication information such as road works, traffic regulations, new roads and facilities, changes in communication areas, etc. using a telephone line and stores them in the database 30. The data is updated at any time.
[0014]
  Next, the in-vehicle device 100 will be described. In the in-vehicle device 100, the arithmetic processing unit 101 is mainly composed of a CPU, mainly a memory 102, a position measurement unit 104, an input unit 105, a display unit 106, an audio output unit 107, and a transmission / reception unit 108. Reference numeral 102 denotes a program storage area 102A (for example, ROM) and a data storage area 102B (for example, RAM).
[0015]
  The program storage area 102 </ b> A of the memory 102 displays a route and a landmark on the display unit 106 based on route data and guidance data transmitted from the information center 10, and outputs a route guidance sound from the voice output unit 107. An arithmetic processing unit 101 such as a route guidance program 150, a data request program 152 for requesting route / guidance data for the next route by comparing the current vehicle position with the received route / guidance data, a control program 154 for controlling the overall operation, etc. Stores the program to be executed in.
[0016]
  On the other hand, the data storage area 102B of the memory 102 is used as a work area when the program is executed, for example, route / guide data (route data and guide data) 160 transmitted from the information center 10, and vehicle-specific ID data. 162, the vehicle position data (longitude / latitude) 164 measured by the position measurement unit 104, or a simplified map database 166 such as a raster map acquired by downloading to be described later is stored.
[0017]
  The vehicle position data 164 includes a plurality of past position data in addition to the current position data measured at predetermined time intervals by the position measurement unit 104. 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.
[0018]
  The position measurement unit 104 measures the position of the vehicle using so-called GPS and outputs current vehicle position data based on longitude and latitude. The position measurement unit 104 receives signals from a plurality of GPS satellites and A GPS receiver that measures the absolute position, a speed sensor, a direction sensor, and the like for measuring the relative position of the vehicle are provided. 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. .
[0019]
  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.
[0020]
  The display unit 106 is a display using liquid crystal, CRT, or the like, and includes the touch panel described above. The transmission / reception unit 108 is a communication device for transmitting / receiving data to / from the information center 10 side, and is configured by communication equipment including a transmission device and a reception device. Similarly to the information center 10 side, a wireless communication system such as a car phone, a mobile phone, and a PHS is used.
[0021]
  Next, the operation of the information center 10 will be described with reference to FIGS.
  FIG. 2 shows a flow of route search processing by the information center 10. Since this process starts from a process (S10) for determining whether or not a route acquisition request from the in-vehicle device 100 is received, transmission of a route acquisition request by the in-vehicle device 100 will be described first. The transmission of this route acquisition request corresponds to step 52 shown in FIG.
[0022]
  As shown in FIG. 1, on the in-vehicle device 100 side, a control program 154 stored in the memory 102 is executed by the arithmetic processing unit 101. In this state, when the data request program 152 stored in the memory 102 is executed based on the user's input operation, each information such as the current vehicle position and the destination measured by the position measurement unit 104 is displayed on the information center 10 side. Is transmitted by the transmitting / receiving unit 108. At this time, an ID for identifying the vehicle and the other vehicle is also transmitted at the same time. Thereby, in the information center 10, the transmission / reception unit 12 receives the route acquisition request and each information transmitted from the vehicle.
[0023]
  In the information center 10, when the transmission / reception unit 12 receives a route acquisition request transmitted from the vehicle, the information center 10 sends the information to the arithmetic processing unit 14. In the arithmetic processing unit 14 that has acquired the information, the route search process is performed by the route search program 20 stored in the memory 18 as described above. .
[0024]
  As shown in FIG. 2, in the route search process, if it is determined that a route acquisition request is received in step 10 (Yes in S10), the process proceeds to step 12 to determine whether there is an input of a destination. That is, the presence / absence of destination input is determined by extracting destination information from each information obtained together with the route acquisition request. Accordingly, if it is determined that there is a destination input (Yes in S12), the destination is determined from the destination information, and the route to the destination is searched in the next step 14. For example, when information such as a telephone number or an address is received as the destination information, the destination is determined using the destination setting data 38 in the database 30. On the other hand, if it cannot be determined that there is a destination input (No in S12), the route search cannot be performed without the destination, so the route search process is terminated and the process proceeds to the control program 26.
[0025]
  In the route search in step 14, a route from the current vehicle position to the destination is searched. This route search is performed by referring to the route search data 32 in the database 30, that is, intersection data, road data, and node data, by the route search program 20 stored in the memory 18. This route search algorithm is known, and is performed by the method disclosed in, for example, JP-A-1-173297 and JP-A-1-173298, and the route having the shortest distance is set as the optimum route. Set a recommended route according to conditions. In this route search, every time a route acquisition request is received from the vehicle side, that is, the in-vehicle device 100, a route from the current vehicle position to the destination is searched. In the information center 10, road information, traffic information, and the like are acquired from the outside by the external information collection unit 40 and updated, for example, every predetermined time so that the latest information can be extracted from the database 30. As a result, a route search is performed for each route acquisition request from the vehicle side, so it is possible to provide the vehicle with a recommended route and guidance data based on the latest data at all times, such as avoiding traffic congestion due to construction or accidents..
[0026]
  The recommended route searched in step 14 is then divided into divided routes in step 16. That is, it is executed by the segment processing program 22 stored in the memory 18, and the searched route is divided into segments of a predetermined length (for example, 2000 meters) which are units of navigation. When the route searched in the route example shown in FIG. 4 is divided, it is divided into, for example, seven segments, that is, divided routes from the first ward to the seventh ward. These divided routes include a data head, intersection information, road information, node information, landmark information, and the like. Further, the segment division unit may be set in time units (for example, one hour unit) or data amount units (for example, 512 byte units), and further, segment division in consideration of geographical or temporal conditions. Units may be set. Thus, since it can be transmitted to the vehicle side at a different geographical position or at a different time in step 30 described later, route guidance based on the road traffic situation changing according to the different geographical position or different time is performed. be able to.
[0027]
  When the route is divided in step 16, it is determined in step 18 whether or not the searched route includes a single road. Here, “mostly includes a single road” means, for example, a case where a single road is included in 80% or more of the entire route, and the ratio can be changed as appropriate according to arbitrary conditions set by the user or the like. Is. Further, the “single road” here is a road that can uniquely determine the course, such as a highway without a branch. When the road to be route guidance is a single route, the user can approach the destination by driving the vehicle along the road even if the route is not route-guided. Therefore, in such a case (Yes in S18), the process proceeds to step 26 without creating the simplified map data including the entire route (S22) and transmitting (S24). On the other hand, if the route does not include a single road (No in S18), the process proceeds to the next step 20.
[0028]
  In step 20, it is determined whether the vehicle side, that is, the in-vehicle device 100 side has a map including the entire searched route. This determination may be made based on the map information already acquired by the vehicle side by extracting the acquired map information from each information obtained together with the route acquisition request described above, or the center side may transmit to the vehicle side before. It may be determined from the transmission map information held as the map information. As a specific example of the map information, for example, the map information is represented by the mesh numbers of the southwest corner and the northeast corner of the map (map information [A1D4] in the map shown in FIG. 7 described later).
[0029]
  If it is determined by the determination process in step 20 that the vehicle side has a map including the entire route (Yes in S20), the simplified map data including the entire route is created (S22) and transmitted (S24). Instead, the process proceeds to step 26. On the other hand, if it can be determined that the map has such a map (No in S20), the process proceeds to creation of simplified map data including the entire next route (S22). Therefore, when the first route acquisition request is received, since the map including the entire route is not in principle, the divided route information created in step 26 except the exception in step 18 (No in S18) is used. When sending to the side for the first time, simplified map data for drawing the entire route is transmitted.
[0030]
  Step 22 is a process performed when the vehicle side does not have the simplified map data (entire route drawing data) including the entire searched route, and the simplified map data is created. This simplified map is drawn as a simplified diagram of road information such as major national roads (such as those with a national road number of up to two digits) and expressways, and topographical information such as rivers. Data taken as data (bitmap data), i.e. raster maps, and road information and terrain information as a simplified map of terrain information such as rivers taken as vector data, i.e. vector maps That is. This map data includes the map drawing data including the starting point and the destination, that is, the entire searched route. However, for example, the map data does not include the whole of Japan and is limited to the minimum data necessary to include the route. Is. Thereby, since the map data of an unnecessary area part can be excluded, the amount of data transmitted to the vehicle side can be reduced, and the communication cost can be reduced. Further, if the map data is compressed with a predetermined algorithm and transmitted as required, further reduction in communication cost can be expected.
[0031]
  In the following step 24, processing for transmitting the simplified map data created in step 24 to the vehicle side is performed. This transmission process is performed via the transmission / reception unit 12, and the simplified map data is wirelessly transmitted to the in-vehicle device 100 side via a predetermined wireless line.
[0032]
  In the creation of the divided route information in step 26, the divided route divided by the route division in step 16 described above and the accompanying drawing data and guide data are obtained from the guidance data 34 by the guide data extraction program 24 stored in the memory 18. Segment information (division data) extracted and added with drawing data and guide data is created and edited. As a result, the creation of the divided route information to be transmitted to the vehicle side, that is, the in-vehicle device 100 is completed. Subsequently, in step 30, the divided route information is transmitted to the in-vehicle device 100 side. These transmission processes are also performed via the transmission / reception unit 12 in the same manner as the transmission of the simplified map data in step 24 described above..
[0033]
  Next, the operation of the in-vehicle device 100 will be described with reference to FIGS.
  FIG. 3 shows a flow of the divided route reception process by the in-vehicle device 100.
  Since this process is for acquiring the divided route information of the section next to the divided section where the moving vehicle is currently located, the control program 154 by the arithmetic processing unit 101 causes the vehicle in the position measuring unit 104 to In the route example shown in FIG. 4 according to the current position, the vehicle is located at a predetermined distance point (for example, 200 meters) from the front of each of the divided route switching points P12, P23, P34, P45, P56, and P67 that are the boundaries of the section. Fired when it is determined that it has been reached.
[0034]
  First, in step 50, the current vehicle position in the position measurement unit 104 is confirmed, and it is determined whether or not the current vehicle position is located around the destination. If it is determined that the current position of the vehicle is located around the destination (Yes in S50), it is not necessary to request more divided route information, so the divided route reception process is terminated and the control program 26 is finished. Move processing to. The route example shown in FIG. 4 is when the vehicle is located in the seventh ward closest to the destination. On the other hand, if it is not determined that it is located around the destination (No in S50), the process proceeds to step 52, and a route acquisition request is transmitted to the information center 10.
[0035]
  In step 52, a route acquisition request is transmitted to the information center 10 by executing the data request program 152 stored in the memory 102 (R1 to R7 shown in FIG. 4). The description of the processing in step 52 is omitted since it has already been described as the premise when the processing in step 10 of the information center 10 described above is described. When the transmission of the route acquisition request in step 52 is completed, the process proceeds to step 54.
[0036]
  In step 54, the simplified map data transmitted from the information center 10 side in response to the first route acquisition request R1 from the in-vehicle device 100 side, that is, the simplified map data is downloaded. This simplified map data is transmitted in step 24 of the route search process by the center side described above, and is transmitted when a simplified map including the entire route is created in step 22. Therefore, even if the first route acquisition request R1 includes a single road in most of the entire route (Yes in S18) or when the in-vehicle device 100 already has a map including the entire route (Yes in S20). Since the simplified map data is not transmitted, the processing in step 54 is not performed. When the simplified map data is received in this way, it is stored in the simplified map database 166 by the memory 102 described above and is referred to by a display process in step 66 described later.
[0037]
  Next, in step 56, the in-vehicle device 100 side receives the instruction to receive the divided route information from the information center 10, that is, the divided route information reception instruction (S28) performed by the route search process of the information center 10 described above. Determine whether or not. If a reception instruction has been received (Yes in S56), the divided path information is transmitted from the information center 10 side, so that the process proceeds to the next step 58 to receive it, and the divided path information is received. Move. On the other hand, if the reception instruction has not been received (No in S56), the vehicle side, that is, the in-vehicle device 100 side, has not been able to receive it due to a communication failure or the like even though the information center 10 has transmitted the division path information reception instruction Since this is the case, the process moves to step 66, and the simplified map data downloaded in step 54 is read from the simplified map database 166 and displayed (M5 in the fifth section shown in FIG. 4).
[0038]
  In step 58, the division path information transmitted from the information center 10 side is received, and it is determined in steps 60 and 62 whether or not the reception is completed before reaching the division path switching point. This judgment may occur when some or all of the segmented route information does not reach the vehicle due to sudden communication failures such as an increase in communication traffic over time or artificial or natural radio wave propagation failures. It is assumed that it will. That is, while waiting for the reception of the next divided route information until the next divided route switching point is reached in step 60 (No in S60), when the next divided route switching point is reached by the movement of the vehicle. (Yes in S60), the vehicle is likely to enter the next section immediately after that, and if the next divided route information has not been received by that time (No in S62), the divided route information is acquired. In step 66, the simplified map data downloaded in step 54 is read from the simplified map database 166 and displayed.
[0039]
  On the other hand, when all the next divided route information can be received before reaching the divided route switching point in step 62, the arithmetic processing unit 101 stores the received divided route information in the memory 102 as the route guidance data 160 and the reception is completed. (Yes in S62). As a result, when the process proceeds to step 64 and the route guidance program 150 stored in the memory 102 is executed, guidance display using the received route guidance data 160 is performed by the display unit 106 and the voice output unit 107. That is, a map or landmark of the divided route is displayed on the display unit 106, and a corresponding voice guidance is output from the voice output unit 107 when turning left or right at an intersection.
[0040]
  Each process of the information center 10 and the in-vehicle device 100 described above is shown as a communication procedure based on the route example shown in FIG. 4 as shown in FIG. Here, FIG. 4 and FIG. 5 will be described. In addition, S ** (** is a number) in parentheses represents each processing step shown in FIG. 2 and FIG.
[0041]
  First, the route acquisition request R1 is transmitted to the information center 10 by starting the divided route information reception process on the in-vehicle device 100 side located at the departure position (S52). Then, the information center 10 receives the route acquisition request R1 (Yes in S10), searches for the route from the current location to the destination (S14), and divides the route (S16). Then, it is determined whether most of the searched routes include a single road (S18) and whether the in-vehicle device 100 has a map including the entire route (S20). Here, the searched route from the first ward to the seventh ward does not include a single road such as a highway, and since it is the first route acquisition request R1, it does not have the map. At 20, both branches in the direction of No. Then, after the divided path information D1 is created (S22), reception of the divided path information is instructed (S28), and further, the divided path information D1 is transmitted (S30). On the other hand, the in-vehicle device 100 side that has transmitted the route acquisition request R1 to the information center 10 side proceeds to reception of simplified map data (S54), and waits for an instruction to receive divided route information (S56). When the divided route information D1 is received (S58, S60, S62), the route guidance S1 based on the divided route information D1 is displayed on the display unit 106 (S64). The simplified map data received here is stored in the simplified map database 166.
[0042]
  If the vehicle continues to travel according to the route guidance S1, the current position of the traveling vehicle (on-vehicle device 100) will eventually be the boundary between the first ward that is traveling and the second ward that is scheduled to travel next, that is, the divided route switching point P12. It reaches 200 meters before. Then, the route acquisition request R2 is transmitted to the information center 10 by starting again the divided route information reception process on the in-vehicle device 100 side (S52). Then, after searching for the route from the current location to the destination (S14) and dividing the route (S16) on the information center 10 side, the vehicle-mounted device 100 already has the simplified map data (No in S20). Then, the division path information D2 is created (S26), and the division path information D2 is transmitted after the division path information reception instruction (S28) (S30). On the in-vehicle device 100 side that has received this division route information reception instruction, the next division route information D2 is received before reaching the division route switching point P12 of the first and second wards (S58, S60, S62). The route guidance S2 based on the divided route information D2 is displayed on the display unit 106 (S64).
[0043]
  Similarly, the in-vehicle device 100 receives the next divided route information D3 until the vehicle traveling according to the route guidance S2 reaches the divided route switching point P23 between the second and third wards (S58, S60, S62). The route guidance S3 based on the divided route information D3 is displayed on the display unit 106 (S64). If the vehicle continues to travel further in accordance with the route guidance S3 and S4 sequentially displayed in this way, it will eventually be 200 meters before the divided route switching point P45 between the fourth ward and the fifth ward scheduled to travel. To reach.
  Here, the divided route information reception process on the vehicle-mounted device 100 side is activated again, and a route acquisition request R5 is transmitted to the information center 10 in order to acquire the next divided route information D5 (S52). Then, by receiving the route acquisition request R5 (Yes in S10), the information center 10 side searches for the route (S14), divides the route (S16), and creates the divided route information D5 (S26) as described above. Are sequentially performed, and the divided path information D5 is transmitted after the instruction to receive the divided path information (S28) (S30).
[0044]
  However, here, as shown in FIG. 4, the position where the divided route information D5 is transmitted corresponds to a communication failure or incapable zone, so the divided route information D5 transmitted by the information center 10 reaches the in-vehicle device 100 side. Absent. Therefore, the in-vehicle device 100 cannot receive the divided route information D5 (No in S62), and reads the simplified map data from the simplified map database 166 stored in the memory 102 to obtain the simplified map M including the entire route. The information is displayed on the display unit 106 (S66). As a result, even if the divided route information D5 to be sent from the information center 10 side cannot be acquired, the current position of the vehicle is located on or near the route from the starting position shown in the simplified map M to the destination. Therefore, the current position of the host vehicle can be confirmed regardless of the communication status with the information center 10.
[0045]
  As described above, according to this embodiment, when the information center 10 side first sends the divided route information for guiding the route from the starting position of the vehicle to the destination to the in-vehicle device 100 side, the entire route is sent. Send simple map data to draw. Thereby, the in-vehicle device 100 side can also receive the simplified map data including the entire route when receiving the divided route information from the information center 10 for the first time. Therefore, for example, even when the vehicle is traveling in a tunnel, a mountainous area, an area where the radio wave is weak, such as a shadow of a building, etc. where radio waves of radio communication means do not reach, the in-vehicle device 100 side first receives it. Since route guidance can be performed based on the simplified map data, the current position of the vehicle can be confirmed regardless of the communication status.
[0046]
  Note that the information center 10 described above creates a simplified map including the entire route when it cannot be determined in step 20 that the vehicle-mounted device 100 side has a map including the entire route (S22). In the present invention, the communication status at a specific position where the divided path information created in step 26 is expected to be transmitted is referred to the communication area data 36 by the communication determination program 25 stored in the memory 18. A simplified map that includes the entire route when it is determined that the communication status at this specific position is poor or incapable of communication(All route drawing data)(S22), and the simplified map data may be transmitted to the in-vehicle device 100 side. Thus, a simplified map is created only when the simplified map data is required on the vehicle side, and the simplified map data is transmitted to the in-vehicle device 100 side. Therefore, unnecessary data transmission from the information center 10 side is performed. Can be avoided as much as possible. Therefore, further reduction in communication cost can be expected.
[0047]
  Next, a reference example will be described based on FIGS. 1 and 6 to 8.
  In the navigation of this reference example, the information center 110 (center side) that divides and transmits the route search / guide data for the route search from the departure position of the vehicle to the destination, as in the embodiment described above, and this transmission The in-vehicle device 200 (on-vehicle device side) that receives the divided data and provides route guidance to the user based on the divided data. Note that the configurations of the information center 110 and the in-vehicle device 200 are substantially the same as those of the information center 10 and the in-vehicle device 100 (FIG. 1) according to the above-described embodiment, and thus description thereof is omitted here.
[0048]
  First, the operation of the information center 110 will be described with reference to FIGS. 1 and 6 to 8.
  FIG. 6 shows a flow of route search processing by the information center 110. This process starts from a process (S110) for determining whether or not a route acquisition request from the in-vehicle device 200 has been received.
This is the same as the transmission of the route acquisition request (S52) by the in-vehicle device 100 described above.
[0049]
  That is, as shown in FIG. 1, on the in-vehicle device 200 side, the control program 154 stored in the memory 102 is executed by the arithmetic processing unit 101. In this state, when the data request program 152 stored in the memory 102 is executed based on the user's input operation, each information such as the current vehicle position and the destination measured by the position measurement unit 104 is displayed on the information center 10 side. Is transmitted by the transmitting / receiving unit 108. At this time, an ID for identifying the vehicle and the other vehicle is also transmitted at the same time. Thereby, in the information center 10, the transmission / reception unit 12 receives the route acquisition request and each information transmitted from the vehicle. On the other hand, in the information center 110, when the transmission / reception unit 12 receives a route acquisition request or the like transmitted from the vehicle, the information center 110 sends the information to the arithmetic processing unit 14. In the arithmetic processing unit 14 that has acquired the information, a route search process is performed by the route search program 20 stored in the memory 18 as described above.
[0050]
  If it is determined that the route acquisition request has been received in step 110 by the route search process (Yes in S110), the process proceeds to step 112, and it is determined whether there is an input of the destination. That is, the presence / absence of destination input is determined by extracting destination information from each information obtained together with the route acquisition request. Thus, if it is determined that there is a destination input (Yes in S112), the destination is determined from the destination information, and a route to the destination is searched in the next step 114. For example, when information such as a telephone number or an address is received as the destination information, the destination is determined using the destination setting data 38 in the database 30. On the other hand, if it cannot be determined that there is a destination input (No in S112), the route search cannot be performed without the destination, so this route search process is terminated and the process proceeds to the control program 26.
[0051]
  In the route search in step 114, a route from the current vehicle position to the destination is searched. This route search is performed by referring to the route search data 32 in the database 30, that is, intersection data, road data, and node data, by the route search program 20 stored in the memory 18. This route search algorithm is known, and is performed by the method disclosed in, for example, JP-A-1-173297 and JP-A-1-173298, and the route having the shortest distance is set as the optimum route. Set a recommended route according to conditions. In this route search, every time a route acquisition request is received from the vehicle side, that is, the in-vehicle device 200, a route from the current vehicle position to the destination is searched. In the information center 110, road information, traffic information, and the like are acquired from the outside by the external information collection unit 40, and updated, for example, every predetermined time so that the latest information can be extracted from the database 30. As a result, a route search is performed for each route acquisition request from the vehicle side, so it is possible to provide the vehicle with a recommended route and guidance data based on the latest data at all times, such as avoiding traffic congestion due to construction or accidents..
[0052]
  The recommended route searched in step 114 is then divided into divided routes in step 116. That is, it is executed by the segment processing program 22 stored in the memory 18, and the searched route is divided into segments of a predetermined length (for example, 2000 meters) which are units of navigation. When the route searched in the route example shown in FIG. 7 is divided, for example, 5 segments, that is, in FIG.Maru 1~Maru 5It is divided into division routes from the first ward to the fifth ward indicated by. These divided routes include a data head, intersection information, road information, node information, landmark information, and the like. Further, the segment division unit may be set in time units (for example, one hour unit) or data amount units (for example, 512 byte units), and further, segment division in consideration of geographical or temporal conditions. Units may be set. Thus, since it can be transmitted to the vehicle side at a different geographical position or at a different time in step 30 described later, route guidance based on the road traffic situation changing according to the different geographical position or different time is performed. be able to.
[0053]
  When the route is divided in step 116, in step 118, the divided route and the accompanying guide data are extracted from the guide data 34 by the guide data extracting program 24 stored in the memory 18, and the guide data is added. Create and edit divided route information (divided data).
[0054]
  In the following step 120, the drawing map data including the route of the created divided route information and its periphery is searched. This search is performed by the guidance data extraction program 24 and is performed by selecting a corresponding map from a drawing map data group stored in the guidance data 34 by a predetermined algorithm. The “periphery” means, for example, a belt-like area having a predetermined width (5 km or the like) centered on the route, and all drawing map data included in this range are to be searched.
[0055]
  Next, in step 122, it is determined whether or not the drawing map data searched in step 120 includes the route and all the surroundings. That is, for example, in the case of a search route (thick line from circle S to circle G) included on the map shown in FIG. 7, the route of the first ward is only obtained by the drawing map data [A-1] searched in step 120.Maru 1In step 124, the drawing map data including other routes and their surroundings is also searched. Accordingly, in the route example shown in FIG. 7, the drawing map data [B-1] is also retrieved, and the drawing map data [A-1] and the drawing map data [B-1] shown in FIG. Therefore, in step 126, an instruction to receive the divided route information is transmitted to the in-vehicle device 200 side.
[0056]
  Then, in step 128, it is determined whether or not there is the same drawing map data searched for in the in-vehicle device 200. This determination is made by recording the drawing map data that the information center 110 has already transmitted to the in-vehicle device 200 side, and collating the record with the searched drawing map information. Moreover, you may take the procedure which confirms whether the map data for drawing exist in the vehicle equipment 200 side each time. If the same is found on the in-vehicle device 200 side by this determination processing (Yes in S128), other drawing map data is removed from the drawing map data searched in steps 120 and 124, excluding the existing drawing map data. It transmits to the device 200 side. Subsequently, in step 134, the divided route information is transmitted to the in-vehicle device 200 side.
[0057]
  On the other hand, if the same is not on the in-vehicle device 200 side (No in S128), the process proceeds to step 130, and all the drawing map data searched in steps 120 and 124 are transmitted to the in-vehicle device 200 side. Subsequently, in step 134, the divided route information is transmitted to the in-vehicle device 200 side. These transmission processes are performed via the transmission / reception unit 12, and the drawing map data and the divided route information are wirelessly transmitted to the in-vehicle device 200 via a predetermined wireless line.
[0058]
  Here, the search for the drawing map data (S120, 122, 124) by the route search processing described above (S120, 122, 124) and the selection of the drawing map data to be transmitted (S128, 132) are used by using a specific route example (FIG. 7). However, a description will be given with reference to FIG.
  FIG. 7 shows a route (thick line) from circle S to circle G.Maru 1~Maru 5It is divided into five sections. The drawing map transmitted from the information center 10 to the in-vehicle device 200 is also divided into five ((A) to (E) shown in FIG. 8).
[0059]
  The drawing map data (FIG. 8A) transmitted to the in-vehicle device 200 first (first) is the drawing map data [A-1] searched in step 120 shown in FIG. Drawing map data [B-1] searched by In this way, the divided path is searchedMaru 1This is because it straddles both drawing maps.
[0060]
  Secondly, the drawing map data (FIG. 8B) transmitted to the in-vehicle device 200 is only the drawing map data [B-2] searched in step 120. The drawing map data [B-1] is also searched in step 124. Since this drawing map data [B-1] already exists on the in-vehicle device 200 side, the processing is performed in accordance with the determination No in step 128. And only the drawing map data [B-2] is transmitted to the in-vehicle device 200 side.
[0061]
  The third drawing map data (FIG. 8C) transmitted to the in-vehicle device 200 is the drawing map data [B-3] searched in step 120 and the drawing map searched in step 124. Data [C-3]. The drawing map data [B-2] is also searched in step 124. Since this drawing map data [B-2] already exists on the in-vehicle device 200 side, the processing is performed according to the determination No in step 128. The drawing map data [B-3] and the drawing map data [C-3] are transmitted to the in-vehicle device 200 side.
[0062]
  The fourth drawing map data (FIG. 8D) transmitted to the in-vehicle device 200 fourth is only the drawing map data [D-3] searched in step 124. The drawing map data [C-3] is also searched in step 120. Since this drawing map data [C-3] already exists on the vehicle-mounted device 200 side, the processing is performed according to the determination No in step 128. Only the map data for drawing [D-3] is transmitted to the in-vehicle device 200 side.
[0063]
  Lastly (fifth) the drawing map data (FIG. 8E) transmitted to the in-vehicle device 200 is only the drawing map data [D-4] searched in step 124. The drawing map data [D-3] is also searched in step 120. Since this drawing map data [D-3] already exists on the in-vehicle device 200 side, the processing is performed according to the determination No in step 128. Only the map data for drawing [D-4] is transmitted to the in-vehicle device 200 side.
[0064]
  In addition, in any of the above-described drawing map data, if the latest one already exists on the in-vehicle device 200 side, the old data is replaced by the transmission, so that the old one is transmitted. Not.
[0065]
  According to the reference example described above, when the drawing map data which is one divided drawing data among the divided drawing map data for guiding the route already exists on the in-vehicle device 200 side, the drawing map data is do not send. As a result, even if the in-vehicle device 200 cannot receive the drawing map data, route guidance can be performed using the existing drawing map data, and transmission of unnecessary data can be omitted. Can do. Therefore, the communication cost can be reduced.
[0066]
  In step 128, it is determined whether or not there is the same drawing map data searched for on the in-vehicle device 200. In this step, all of the guide routes included in the searched drawing map data are single. It may also be determined whether or not the map is made of a route, and the drawing map data corresponding to the route is excluded from step 132, and other drawing map data may be transmitted. As a result, even if the in-vehicle device 200 cannot receive the drawing map data, there is no route guidance when all of the guide routes included in the drawing map data consist of a single route. However, if you go straight along the road, you can approach the destination, so you can save unnecessary data. Therefore, the communication cost can be further reduced.
[0067]
【The invention's effect】
  Claim1In the described invention, the drawing data and the guidance data transmitted from the center side to the in-vehicle device side are transmitted corresponding to different geographical positions or different times on the in-vehicle device side, and by the communication status determination on the center side If it is determined that the communication status at a specific position where these data are expected to be transmitted is communication failure or the like, all route drawing data is transmitted to the in-vehicle device side. Thereby, the in-vehicle device side can receive all route drawing data when the center side determines that the communication status at the specific position is communication failure or the like by the communication status determination. Therefore, for example, even when the vehicle is traveling in a tunnel or mountainous area where radio waves of radio communication means do not reach, areas where the radio waves are weak, such as shadows of buildings, etc. Where the current position of the vehicle can be confirmed based on the received all route drawing data, a highly reliable navigation method can be provided regardless of the communication status.
[0068]
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a navigation system according to an embodiment of the present invention.
FIG. 2 is a flowchart of route search processing in the information center according to the present embodiment.
FIG. 3 is a flowchart of division path information reception processing in the in-vehicle device according to the present embodiment.
FIG. 4 is an explanatory diagram showing a complementary relationship between division route information sequentially received by the in-vehicle device according to the present embodiment and a simplified map referred to in a communication failure zone.
FIG. 5 is an explanatory diagram showing a flow of communication procedures between the information center and the in-vehicle device in the navigation system according to the present embodiment.
[Fig. 6]Reference exampleIt is a flowchart of the route search process in an information center.
[Fig. 7]Reference exampleIt is explanatory drawing which showed an example of the map data for drawing searched by a route search process.
[Fig. 8]Reference exampleIt is explanatory drawing which showed an example of the map data for drawing transmitted sequentially by a route search process, (A)-(E) shows the order.
[Explanation of symbols]
  10 Information Center (Center side)
  100 On-vehicle device (on-vehicle device side)
  104 Position measurementPart
  D1 to D7 Dividing path information (divided data)

Claims (1)

This is a navigation method in which drawing data and guidance data for guiding a route from a starting position of a vehicle to a destination are divided and sent from the center side to the in-vehicle device side, and route guidance is performed on the in-vehicle device side based on the data. And
Drawing data and guidance data for guiding the divided route are transmitted from the center side to the in-vehicle device side at different geographical positions or at different times,
The center side determines the communication status of a specific position where the data is expected to be transmitted, and if it is determined that the communication status of the specific position is poor communication or incapable of communication, all routes for drawing the entire route A navigation method characterized by transmitting drawing data.

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