JP2006275766A - Navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately set a start point on any road to search a route, even when expressways and general roads exist in the vicinity of the current position. <P>SOLUTION: In this navigation system, the start point for the route search is set on the road of the kind similar to that of the road it has traveled the last, and is nearest to the current position, when route search is conducted. The start point for the route search may be set on the road which is identical to the road traveled last. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a navigation device, and more particularly to a route search technique for an in-vehicle navigation device.

  A vehicle-mounted navigation device that sets a link closest to the current position as a start link and searches for a route from the start link to a destination is known.

JP-A-8-178682

  However, when the link closest to the current position is set as the start link, inconvenience may occur. For example, as shown in FIG. 8, the parking lot 510 is near the highway 505. It is assumed that the vehicle enters the adjacent parking lot 510 through the general road 501 and stops as shown in the travel locus 521. When a route search is performed at this point, the link of the expressway 505 closest to the parking lot 510 is set as the start link, and a route starting from the expressway is searched. This makes it impossible to search for an appropriate route.

  Accordingly, an object of the present invention is to perform a route search by setting a start link more accurately.

  In order to solve the above problems, the navigation device of the present invention performs a route search by setting a starting point on the same type of road as the last traveled road.

  For example, the navigation device of the present invention includes means for storing link data of links constituting roads on a map, means for calculating a current position, route search means for searching for a route from the current position to a destination, have. Then, the route search means searches for a route from a link belonging to a road of the same road type as the road to which the current position lastly belongs.

  The navigation device also stores means for storing link data of links constituting roads on the map, map matching means for obtaining the current position on the map by map matching, and from the current position to the destination using the link data. Route search means for searching for the route. The map matching means obtains the current position at a position on the link or not on the link, and the route search means has the same road type as the link where the current position finally matched on the link exists. A road type link may be set as a start link, and a route from the start link to the destination may be searched.

  Further, the route search means may search for a route from a link belonging to the same road as the road to which the current position lastly belongs.

  An embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an in-vehicle navigation device 100. As shown in the figure, the in-vehicle navigation device 100 includes an arithmetic processing unit 1, a display 2, a storage device 3, a voice input / output device 4, an input device 5, a wheel speed sensor 6, a geomagnetic sensor 7, It has a gyro sensor 8, a GPS (Global Positioning System) receiver 9, an in-vehicle LAN device 11, an FM multiplex broadcast receiver 12, a beacon receiver 13, and a network communication device 15.

  The arithmetic processing unit 1 is a central unit that performs various processes. For example, the present location is detected based on information output from the various sensors 6 to 8 and the GPS receiver 9. Further, map data necessary for display is read out from the storage device 3 based on the obtained current location information. Further, the read map data is developed in graphics, and a mark indicating the current location is superimposed on the map data and displayed on the display 2. Further, using the map data stored in the storage device 3 and the time-series traffic information received from the traffic information distribution server 200, an optimum route (recommended) connecting the destination instructed by the user and the current location (departure location) Route). Further, the user is guided using the voice input / output device 4 and the display 2.

  The display 2 is a unit that displays graphics information generated by the arithmetic processing unit 1. The display 2 is composed of a CRT, a liquid crystal display, or the like. The signal S1 between the arithmetic processing unit 1 and the display 2 is generally connected by an RGB signal or an NTSC (National Television System Committee) signal.

  The storage device 3 is composed of a storage medium such as a CD-ROM, DVD-ROM, HDD, or IC card. In this storage medium, map data 300 is stored.

  FIG. 2 is a diagram illustrating the configuration of the map data 300. The map data 300 includes, for each mesh identification code (mesh ID) 310, which is a partitioned area on the map, link data 311 of each link constituting a road included in the mesh area.

  For each link ID 321, the link data 311 includes coordinate information 322 of two nodes (start node and end node) constituting the link, road type information 323 including the link, link length information 324 indicating the link length, link The travel time 325 includes a link ID (connection link ID) 326 of a link connected to each of the two nodes. Here, by distinguishing the start node and the end node for the two nodes constituting the link, the upward direction and the downward direction of the same road are managed as different links. Further, the link travel time 325 may be a link travel time associated with each condition such as date and weather.

  The map data 300 also includes information (name, type, coordinate information, etc.) of map components (for example, parking lots) other than roads included in the corresponding mesh area.

  Returning to FIG. The voice input / output device 4 converts the message to the user generated by the arithmetic processing unit 1 into a voice signal and outputs it. Also, a process of recognizing the voice uttered by the user and transferring the contents to the arithmetic processing unit 1 is performed.

  The input device 5 is a unit that receives instructions from the user. The input device 5 includes a hard switch such as a scroll key and a scale change key, a joystick, a touch panel pasted on a display, and the like.

  The sensors 6 to 8 and the GPS receiver 9 are used for detecting the current location (vehicle position) by the vehicle-mounted navigation device 100. The wheel speed sensor 6 measures the distance from the product of the wheel circumference and the measured number of rotations of the wheel, and further measures the angle at which the moving body is bent from the difference in the number of rotations of the paired wheels. The geomagnetic sensor 7 detects the magnetic field held by the earth and detects the direction in which the moving body is facing. The gyro 8 is configured by an optical fiber gyro, a vibration gyro, or the like, and detects an angle at which the moving body rotates. The GPS receiver 9 receives a signal from a GPS satellite and measures the distance between the mobile body and the GPS satellite and the rate of change of the distance with respect to three or more satellites to thereby determine the current position, travel speed, and travel of the mobile body. Measure orientation.

  The in-vehicle LAN device 11 receives various information of the vehicle on which the in-vehicle navigation device 100 is mounted, such as door opening / closing information, light lighting state information, engine status, failure diagnosis result, and the like.

  The FM multiplex broadcast receiving apparatus 12 receives rough current traffic information, regulation information, SA / PA (service station / parking) information, parking lot information, weather information, etc. sent from the FM multiplex broadcast station as FM multiplex broadcast signals. To do.

  The beacon receiving device 13 receives current traffic information, regulation information, SA / PA information, parking lot information, and the like sent from the beacon.

  The network communication device 15 mediates exchange of information between the in-vehicle navigation device 100 and a server that distributes traffic information.

  FIG. 3 is a functional block diagram of the arithmetic processing unit 1.

  As illustrated, the arithmetic processing unit 1 includes a user operation analysis unit 41, a route search unit 42, a route guidance unit 43, a current position calculation unit 44, an information storage unit 45, and a display processing unit 46.

  The user operation analysis unit 41 receives a request from the user input to the input device 5, analyzes the request content, and controls each unit of the arithmetic processing unit 1 so that processing corresponding to the request content is executed. To do. For example, when the user requests a search for a recommended route, the display processing unit 45 is requested to display a map on the display 2 in order to set a destination. Further, it requests the route search unit 42 to calculate a route from the current location (departure location) to the destination.

  The current position calculation unit 44 uses distance data and angle data obtained as a result of integrating the distance pulse data S5 measured by the wheel speed sensor 6 and the angular acceleration data S7 measured by the gyro 8, respectively. , The virtual current position (X ′, Y ′), which is the position after the vehicle travels, is periodically calculated from the initial position (X, Y). Further, a candidate point of the current position is obtained on a road (link) having the highest shape correlation by performing map matching processing using the calculation result.

  The route search unit 42 uses a Dijkstra method or the like to search for a route that minimizes the cost (for example, travel time) of a route connecting two designated points (current location, destination).

  The route guidance unit 43 performs route guidance using the route searched by the route search unit 42. For example, the information on the route is compared with the information on the current location, and the voice input / output device 4 is used to inform the user by voice whether the vehicle should go straight before passing an intersection or the like. Further, the route guiding unit 43 displays the direction to travel on the map displayed on the display 2 and notifies the user of the recommended route.

  The display processing unit 46 receives map data in an area required to be displayed on the display 2 from the storage device 3, and at a specified scale and drawing method, roads, other map components, current location, destination, A map drawing command is generated so as to draw a mark such as an arrow for the recommended route. Then, the generated command is transmitted to the display 2.

  FIG. 4 is a diagram illustrating a hardware configuration example of the arithmetic processing unit 1.

  As illustrated, the arithmetic processing unit 1 has a configuration in which devices are connected by a bus 32. The arithmetic processing unit 1 includes a CPU (Central Processing Unit) 21 that executes various processes such as numerical calculation and control of each device, and a RAM (Random Access Memory) that stores map data, arithmetic data, and the like read from the storage device 3. ) 22, a ROM (Read Only Memory) 23 for storing programs and data, a DMA (Direct Memory Access) 24 for transferring data between the memories and between the memory and each device, and graphics drawing. In addition, a drawing controller 25 that performs display control, a video random access memory (VRAM) 26 that stores graphics image data, a color palette 27 that converts image data into RGB signals, and an A / D that converts analog signals into digital signals. Converter 28 and an SCI (Serial Communication Interface) that converts the serial signal into a parallel signal synchronized with the bus. ace) 29, a PIO (Parallel Input / Output) 30 that puts a parallel signal on the bus in synchronization with the bus, and a counter 31 that integrates the pulse signal.

  [Description of Operation] Next, the operation of the in-vehicle navigation device 100 having the above-described configuration will be described.

  The vehicle-mounted navigation device 100 performs a process for obtaining a candidate point for the current position every time the vehicle travels a predetermined distance.

  FIG. 5 is a flowchart of the current position calculation process.

  Each time the current position calculation unit 44 travels a predetermined distance (for example, 20 m), the relative displacement (movement distance, movement direction) from the previous candidate point of the current position is calculated by the GPS receiver 9 and the various sensors 6 to 8. Find from output. Then, the virtual current position is obtained by adding the relative displacement to the previous candidate point (S102).

  Next, the current position calculation unit 55 tries to select a link that matches the virtual current position by map matching (S104). Specifically, the current position calculation unit 44 refers to the link data 321 and extracts a link that exists within a predetermined range from the virtual current position. Furthermore, the link from which the difference of the direction and the advancing direction of a vehicle is less than predetermined value among the searched links is selected.

  When any link is selected in this way (Yes in S104), the current position calculation unit 44 calculates a new candidate point on the selected link (S106). In this way, candidate points that match on any of the links are referred to as “matching candidate points”.

  On the other hand, when the link is not selected (No in S104), the current position calculation unit 44 directly uses the virtual current position obtained in S102 as a new candidate point (S108). Note that candidate points that do not match any link are called “free candidate points”.

  The current position calculation unit 44 repeats the above processing (S102 to S108) to update the current position candidate points.

  Next, route search processing will be described.

  FIG. 6 is a flowchart of route search processing. This flow is started when a route search request is received from the user via the input device 5.

  First, the route search unit 42 sets a departure place and a destination (S210). Here, a case where the current position is set as the departure point will be described.

  The route search unit 42 sets a start link and an end link (S220), and searches for a route from the start link to the end link (S230). For example, the route search unit 42 searches for a route with the minimum total cost by using the Dijkstra method or the like using the link travel time as a cost.

  Here, the route search unit 42 refers to the link data 321, selects the link closest to the destination, and sets it as the end link.

  On the other hand, the start link is set as follows.

  FIG. 7 is a flowchart of the start link setting process. FIG. 8 is a diagram for specifically explaining a method of selecting a start link.

  In FIG. 8, the parking lot 510 is in the vicinity of the highway 505. It is assumed that the vehicle passes through the general road 501 and enters the adjacent parking lot 510 and stops as shown in the travel locus 521. Thereafter, it is assumed that the vehicle starts toward a general road 502 different from the road 521 as indicated by a travel locus 522. Then, it is assumed that the user requests a route search from the in-vehicle navigation device 100 at the point of the parking lot 510.

  While the vehicle is traveling on the general road 501, the current position calculation unit 44 can match the virtual current position on the link of the general road 501. Therefore, a matching candidate point is calculated on the link of the general road 501.

  On the other hand, when the vehicle enters the parking lot 510, the current position calculation unit 44 cannot match the virtual current position to the link. Therefore, free candidate points that do not match on any link are calculated.

  The current position calculation unit 44 sequentially updates the candidate points, but accumulates past candidate points in the information storage unit 45 together with information on matching candidate points or free candidate points.

  The start link setting process will be described with reference to FIG.

  First, the route search unit 42 extracts information on the last stored matching candidate point (in other words, the latest matching candidate point) from the past matching candidate points stored in the information storage unit 44. Then, referring to the link data 321, the road type 323 of the link where the matching candidate point exists is specified (S222).

  As shown in FIG. 8, when a route search request is made in the parking lot 510 after traveling on the trajectory 521, the last matching candidate point is on the link of the general road 501. Therefore, “general road” is specified as the road type of the link of the last matching candidate point.

  Next, the route search unit 42 receives the current position candidate point from the current position calculation unit 44. Furthermore, the route search unit 42 refers to the link data 321 and extracts one link in order from the candidate point (S224).

  In the example of FIG. 8, the route search unit 42 receives free candidate points for the position of the parking lot 510 from the current position calculation unit 44. Then, the link of the nearest expressway 505 is extracted.

  Next, it is determined whether or not the road type of the link extracted in S224 is the same as the road type of the link of the last matching candidate point specified in S222 (S226).

  When the road types are different (No in S226), the route search unit 42 returns to S224, selects a link next to the link extracted last time from the candidate point of the current position, and performs the subsequent processing (S226).

  In the example of FIG. 8, the nearest link is an “highway”, whereas the last matching candidate point link is a “general road”. Accordingly, since the road types are different, the route search unit 42 returns to S224 and extracts the link of the general road 502 as the link next to the link extracted last time.

  When the road types are the same link (Yes in S226), the route search unit 42 sets the link extracted in S222 as the start link (S228), and ends the start link setting process.

  In the example of FIG. 8, the link of the road 502 is the same type (general road) as the road of the last matching candidate point link. Therefore, the route search unit 42 sets the link of the road 502 as the start link.

  Thus, when the start link is set, the route search unit 42 searches for a route from the start link to the destination (S230).

  The embodiment of the present invention has been described above.

  According to the above embodiment, the starting point of the route search can be obtained on the same type of road as the last traveled road. Therefore, as shown in FIG. 8, it is possible to prevent a route starting from the highway from being searched because the highway is closest to the vehicle even though it is not actually on the highway.

  The present invention is not limited to the above embodiment. The above embodiment can be variously modified within the scope of the gist of the present invention.

  For example, the last matching link may be used as the start link for route search. If the parking lot is small, it usually returns to the original road, so this does not cause a big problem. As shown in FIG. 8, when the parking lot is wide and the road on the entrance side is different from the road on the exit side, it is possible to prevent a road of a completely different road type from being set as the starting point, although some errors occur.

  Further, in S226 of FIG. 7, it is determined whether or not the roads are of the same type, but the determination of whether or not the roads are of a specific type may be determined based on whether or not they match. For example, the route search unit 42 first determines whether or not the road type identified in S222 is a highway. Furthermore, it is determined whether or not the road type of the link extracted in S224 is a highway. If the determination results match (Yes in S226), the link extracted in S224 is set as the start link. In such a case, the determination result of whether it is a toll road or a general road may be used.

  Further, in the above embodiment, the case where there is one candidate point at the current position has been described for ease of understanding, but there may be a plurality of candidate points. That is, the current position calculation unit 44 may perform the above processing (S102 to S108) for a plurality of candidate points. In such a case, the reliability is calculated for each candidate point, and the candidate point with the maximum reliability is set as a candidate point (display candidate point) used for displaying the current position. Then, in the process for obtaining the start link in FIG. 7, links are extracted in order from the candidate point with the candidate point having the maximum reliability as a reference (S224).

  In the above embodiment, an example in which the present invention is applied to a vehicle-mounted navigation device has been described. However, the present invention can also be applied to a navigation device other than a vehicle-mounted navigation device.

FIG. 1 is a schematic configuration diagram of an in-vehicle navigation device. FIG. 2 is a diagram illustrating a configuration example of map data stored in the storage device 3. FIG. 3 is a diagram illustrating a hardware configuration of the arithmetic processing unit 1. FIG. 4 is a diagram illustrating a functional configuration of the arithmetic processing unit 1. FIG. 5 is a flowchart of the current position calculation process. FIG. 6 is a flowchart of route search processing. FIG. 7 is a flowchart of start link identification processing. FIG. 8 is a map for specifically explaining the embodiment.

Explanation of symbols

100: In-vehicle navigation device,
DESCRIPTION OF SYMBOLS 1 ... Arithmetic processing part, 2 ... Display, 3 ... Memory | storage device, 4 ... Voice input / output device, 5 ... Input device, 6 ... Wheel speed sensor, 7 ... Geomagnetism Sensor: 8 ... Gyro, 9 ... GPS receiver, 21 ... CPU, 22 ... RAM, 23 ... ROM, 24 ... DMA, 25 ... Drawing controller, 26 ... VRAM, 27 ... color palette, 28 ... A / D converter, 29 ... SCI, 30 ... PIO, 31 ... counter, 41 ... user operation analysis unit, 42 ... Route search unit, 43 ... Route guidance unit, 44 ... Current position calculation unit, 45 ... Information storage unit, 46 ... Display processing unit

Claims (5)

A navigation device,
Means for storing link data of links constituting roads on a map;
Means for calculating the current position;
Route search means for searching for a route from the current position to the destination,
The route search means includes
A navigation device characterized by searching for a route starting from a link belonging to a road of the same road type as a road to which a link where the current position last exists belongs. A navigation device,
Means for storing link data of links constituting roads on a map;
Map matching means for obtaining the current position on the map by map matching;
Route search means for searching for a route from the current position to the destination using the link data;
The map matching means obtains the current position at a position on the link or not on the link,
The route search means includes
A navigation device characterized by setting a link of the same road type as the road type of the link where the current position exists at the last matching on the link as a start link, and searching for a route from the start link to the destination . In claim 2,
The route search means includes
Finally, a link of the same road type as the road type of the link where the current position exists on the link is the closest to the current position is set as the start link, and the link from the start link to the destination A navigation device characterized by searching for a route. In claim 1,
The navigation device according to claim 1, wherein the road type includes at least one of an expressway, a toll road, and a general road. A navigation device,
Means for storing link data of links constituting roads on a map;
Means for calculating the current position;
Route search means for searching for a route from the current position to the destination,
The route search means includes
A navigation device characterized by searching for a route from a link belonging to the same road as a road to which the current position lastly belongs.

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