JP2000146615A - On-vehicle dynamic route calculator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make calculable a reasonable route where actual traffic situations are taken into account by evaluating the traveling time of a new traffic information link when it is received based on the measurements of traveling of a vehicle and the evaluation results of traveling time for every classification of road, thereby removing or correcting the traveling time having a large error. SOLUTION: As a preprocessing for dynamic route calculation, a traveling time contained in traffic information received by a receiver is evaluated in a traveling time acquisition processing with reference to a traveling time accuracy previously calculated through traveling time accuracy calculation processing. If the traveling time accuracy is acceptable, the received traveling time is employed, as it is, as a traveling time acquisition value otherwise a traveling time calculated based on the length or extent of traffic jam is employed as the traveling time acquisition value. More specifically, the traveling time from current position to a goal is calculated by taking account of the traveling time acquired through traveling time acquisition processing for the link cost of road network.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads out road network data in a range including a current position of a vehicle, a destination, and a transit point from a storage device in accordance with setting of a destination and a transit point by a driver, The present invention relates to a route calculation device that can calculate a route to a destination based on data and indicate the route to a driver. In particular, the present invention relates to an in-vehicle dynamic route calculation device that calculates a route in consideration of traffic information received by a receiver.

[0002]

2. Description of the Related Art Conventionally, there has been known a navigation device developed for displaying the position and direction of a vehicle on a screen to facilitate traveling on an unknown land or at night.
This navigation device is equipped with a display, a direction sensor, a distance sensor, a GPS receiver, a road map memory, and a microcomputer in a vehicle. The direction data input from the direction sensor, the traveling distance data input from the distance sensor, and The vehicle position is detected based on the road pattern stored in the road map memory, and this vehicle position is displayed on a display together with the road map.

In this case, in order to select a traveling route from the departure point to the destination, the microcomputer automatically determines the current route from the departure point to the destination according to the input of the destination setting by the driver. (See Japanese Patent Application Laid-Open No. 8-178682). According to this method, a point obtained by dividing a road to be subjected to route calculation for each branch point is set as a node, a road connecting the nodes is set as a link (hereinafter, referred to as a “navi link”), and a departure place (or a destination) is set. The node or link closest to the destination is the starting point, the node or link closest to the destination (or departure point) is the end point, the entire tree of links from the starting point to the end point is searched, and the link of the root constituting the tree is traversed. This is a method of sequentially adding time or distance (hereinafter, referred to as “navi link cost”) to select a route with the lowest link cost to reach a destination or a departure point.

On the other hand, traffic information such as traffic congestion corresponding to a link managed by an external traffic information center (hereinafter referred to as "traffic information link") and link cost corresponding to a traffic information link measured by the traffic information center (hereinafter referred to as "link cost"). , "Travel time"
) Can be obtained through a beacon receiver or an FM multiplex receiver. At this time, since the traffic information link and the navigation link do not correspond one-to-one, the travel time is converted into the navigation link cost using a correspondence table of the traffic information link and the navigation link (hereinafter, referred to as a “link correspondence table”). A so-called dynamic route calculation method is also known in which a route is calculated taking traffic information into account when sequentially adding link costs during route calculation (see Japanese Patent Application Laid-Open No. 8-87697).

However, in this dynamic route calculation method, since each traffic information link may include a measurement error, it corresponds to the road on which the vehicle has traveled based on the actually measured travel time of the vehicle. The coefficient for correcting the travel time associated with the traffic information link has been updated (Japanese Unexamined Patent Application Publication No.
No. 293094).

[0006]

However, in the above dynamic route calculation method, the coefficient for correcting the travel time has not been updated for each road classification. The actual travel time of the traffic information link has a measurement error depending on the classification of the road. If the route calculation is performed ignoring the measurement error for each road classification, an appropriate route may not be calculated. The present invention has been made in view of the above problems.

[0007]

The features of the on-vehicle dynamic route calculation device of the present invention are as follows. As a pre-process for performing the dynamic route calculation, in the travel time acquisition process, the travel time accuracy PT already calculated by the travel time accuracy calculation means is referred to, and the travel time included in the traffic information received by the receiver is evaluated. . If the travel time accuracy PT is good, the received travel time is used as it is as the travel time acquisition value AT. If the travel time accuracy PT is bad, the travel time calculated based on the traffic congestion length or the degree of traffic congestion is used. Adopt as AT. Thus, the route from the current location to the destination is calculated by taking into account the travel time acquired in the travel time acquisition process with respect to the link cost of the road network (claim 1).

The travel time accuracy calculation process calculates the travel time accuracy from the travel time acquired by the travel time acquisition means and the actual measurement value of the travel time obtained based on the vehicle position detecting means. The travel time accuracy PT that has been updated is updated (claim 2). Further, the travel time accuracy calculation processing includes the travel time accuracy P for each predetermined road classification.
T is calculated (claim 3).

According to the vehicle-mounted dynamic route calculation device,
Even if a traffic information link that has not traveled becomes a target of route calculation because the travel time accuracy PT already obtained is referred to, the validity of the travel time of the traffic information link can be evaluated. As a result, for the driver,
It is possible to provide a practically convenient route.

In addition, the travel time accuracy PT is calculated from the travel time acquired by the travel time acquisition means and the actually measured travel time obtained based on the vehicle position detection means each time traffic information is received by the receiver. Is done. Further, since the travel time accuracy PT is calculated for each predetermined road classification, the accuracy of the travel time included in the traffic information received by the receiver can be evaluated for each road classification. As a result, the travel time from the outside, which has a large error, can be eliminated and corrected, so that the route can be calculated in consideration of the travel time with higher accuracy.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. <Configuration of In-Vehicle Dynamic Route Calculation Apparatus> As shown in FIG. 3, an in-vehicle dynamic route calculation apparatus 1 (hereinafter simply referred to as an apparatus 1) includes a direction sensor 6 using a gyro or the like, Speed sensor 5 or distance sensor 8, GPS receiver 7, display device 3 for displaying a route on a road network, input means 4 for inputting a destination or the like, storage storing road network data Device 2, beacon receiver 9 for receiving external traffic information
And an FM multiplex receiver 10, and a speaker 18 for providing route guidance by voice. The storage device 2 includes an IC card, an FD, an HD, a CD, and a DV.
D corresponds to this.

The device 1 controls the DRAM 173 in the portion where the road network obtained from the storage device 2 is stored and controls the DRAM 173 in the portion where the road network is stored by the display device 3 for displaying the road network. Integrated data obtained by integrating the display control unit 12, the input processing unit 13, which is an interface unit of the input means 4, the travel distance obtained from the vehicle speed sensor 5 or the distance sensor 8, and the travel direction change amount obtained from the direction sensor 6, GP
A vehicle position detection processing unit 14 that detects a vehicle position based on the vehicle position positioning data obtained from the S receiver 7 and the road network data obtained from the storage device 2, and a departure place and a destination obtained from the storage device 2 A dynamic route calculation processing unit 16 for calculating a route from the departure point to the destination based on the road network data of the area including the area, and a vehicle which should proceed to the driver before the branch point when the vehicle travels on the calculated route And a voice control unit 15 for teaching a road. Note that the memory control unit 11, the display control unit 12, the input processing unit 1
3. The vehicle position detection unit 14, the dynamic route calculation processing unit 16 and the voice control unit 15 are operated by the CPU 171.
When each is operated, the SRAM 172 and the DRAM 173 are used.

<Outline of Static Route Calculation> An outline of a static route calculation based on a road network without taking traffic information into consideration will be described. The storage device 2 divides road network data into meshes, and stores data obtained by combining nodes and navigation links for each mesh. The data obtained by combining the node and the navigation link is used for route calculation, road display, and vehicle position detection.
The storage device 2 also includes character data such as background data and place names, in addition to data obtained by combining nodes and navigation links. The information of the navigation link required at the time of route calculation is a link number, a navigation link cost, a road type, a navigation link number of one or more connection destinations, and a work for route calculation. The road types include expressway national roads, urban expressways, rampways, general national roads, major local roads, general prefectural roads, general city roads in designated cities, and other narrow streets.

In this manner, the storage control unit 1
The CPU 171 determines the route from the departure point to the destination by the CPU 171 based on the network information such as the link number included in the link data included in the road network data of the area including the departure point and the destination read out on the DRAM 173 through the CPU 1. calculate.

<Provision of Traffic Information> The provision of traffic information will be described with reference to FIGS. FIG. 1 is a schematic diagram of a ground-side system that provides traffic information to the device 1. This system includes a road beacon A installed on the road and a communication line (public line or dedicated line) B connected to the road beacon A.
And an information center C connected via the The information center C manages traffic information corresponding to traffic information links connecting major intersections. This traffic information link has mesh information, a traffic information link number, a degree of congestion, a congestion length, and a travel time, as shown in FIG. The information possessed by the traffic information link is transmitted from the information center C to the road beacon A at regular intervals through the communication line B, and further transmitted to a beacon receiver of a vehicle passing near the road beacon A. In the present application, the provision of traffic information from beacons will be described, but there is essentially no difference even in traffic information from FM multiplex broadcasting.

<Overview of Dynamic Route Calculation Processing> The processing of the dynamic route calculation processing section 16 will be described with reference to the flowchart of FIG. For simplicity, it is assumed that traffic information can be normally received from road beacons before dynamic route calculation, and that traffic information links are running after dynamic route calculation. First, based on the traffic information from the beacon, the travel time possessed by the traffic information link is referred to the travel time accuracy PT already updated in the processing 5 and the travel time acquisition value AT
(Process 1). The travel time acquisition value AT is converted to a navigation time travel time adoption value GT so as to be a navigation link cost per navigation link (process 2). Thus, the route from the current position to the destination is calculated based on the travel time adoption value GT of the navigation link (process 3). As a pre-process for updating the travel time accuracy PT at the time of traveling on the route after completion of the route calculation, the actual value MT of the travel time of the traffic information link is calculated using the function of the vehicle position detection unit 14 (Process 4). . The travel time accuracy PT is updated from the travel time acquisition value AT of the traffic information link and the actually measured value MT of the travel time (process 5). If a beacon is received after the end of the process 5, the process returns to the process 1.

<Details of Dynamic Route Calculation Process> Details of the dynamic route calculation process will be described with reference to FIGS. (1) Processing until reception of traffic information from a beacon In S1 of FIG. 4, conditions such as setting of a stopover are set by a driver, and a route is initially calculated based on a navigation link. The driver starts a trip according to this route. During traveling, the device 1 always determines whether or not traffic information has been received from the road beacon A. When the traffic information is received, the process proceeds to FIG. 5, and when the traffic information is not received, the process proceeds to S3 (S2). In S3, when the vehicle traveling on the route approaches the fork, the device 1 determines that it is the timing of the guidance instruction to teach the road to be advanced, and the voice control unit 15 and the display control unit 12 A guidance instruction is issued (S4), and the process proceeds to S2. If it is determined that it is not the timing of the guidance instruction, the process proceeds to S5.

(2) Process of Acquiring Travel Time Acquisition Value AT in Traffic Information Link In step S2, after receiving the traffic information, the process proceeds to FIG.
In S10 and S11 of FIG. 5, the traffic information links obtained from the road beacon A and once stored in the DRAM 173 are sequentially taken out. If not, the process proceeds to S12.

In S12, if the traffic information link extracted from the DRAM 173 has a travel time, the process proceeds to S13. If the traffic information link does not have a travel time,
Move to S16. In S13,
Travel time accuracy PT of the class responding to the traffic information link
From the travel time accuracy table (FIG. 12). Immediately after the apparatus 1 is turned on, an initial value (maximum value) is stored in the travel time accuracy table. The travel time accuracy PT represents the accuracy of travel time possessed by a predetermined type of traffic information link in the same area. The update of the travel time accuracy PT will be described later.

The travel time accuracy P referred to in S13 of FIG.
It is determined whether or not T is within a predetermined range, that is, whether or not the travel time of the traffic information link has high accuracy (S14). For example, if the travel time accuracy PT is in the range of 0 to 0.3, the travel time accuracy is determined to be high, the travel time of the traffic information link is adopted as the travel time acquisition value AT (S15), and the process returns to S10. .

On the other hand, if the travel time accuracy PT is not in the range of 0 to 0.3, the travel time accuracy is determined to be poor, and the travel time acquisition value AT is determined based on the traffic jam length or the traffic jam level of the traffic information link. Then, the process proceeds to S16.

In S16 of FIG. 5, it is confirmed whether or not the traffic information link has a traffic jam length. If there is a traffic jam length, the process proceeds to S17, and the travel time acquisition value AT is calculated from the traffic jam length.
Ask for. For example, as shown in FIG.
In K, the link length is L0 and the average vehicle speed during non-congestion is V
When the traffic congestion length is L1 and the average vehicle speed during the traffic congestion is V1, the travel time acquisition value AT is calculated by equation (1) (S1).
7) Return to S10.

(Equation 1)

In S16, if the traffic information link does not have the traffic jam length, the travel time acquisition value AT is calculated based on the traffic jam degree.
The process proceeds to S18 in order to calculate. In S18, it is confirmed whether or not the traffic information link has a degree of traffic congestion. If there is a degree of congestion, the process proceeds to S19, and a travel time acquisition value AT is obtained from the degree of congestion. For example, it is assumed that the traffic information link LK corresponds to the navigation links LN1 and LN2 as shown in FIG. LN1 and LN2 can be obtained by searching the link correspondence table of the storage device 2. Next, for the road network stored in the storage device 2, navigation link costs CT1 and CT2 corresponding to the navigation links LN1 and LN2 are obtained. For the degree of congestion, an appropriate coefficient KL is obtained based on a coefficient table (not shown) corresponding to each degree of congestion. Thus, the travel time acquisition value AT is calculated by the equation (2) (S19), and returns to S10.

(Equation 2) Note that the travel time acquisition value AT obtained as described above is
It is stored in the RAM 173.

(3) Processing for Calculation of Travel Time Adopted Value GT for Navi Link In step S11 of FIG. 5, the processing shifts to the case where the processing of all traffic information links is completed. 6, in S20 and S21 in FIG. 6, the navigation links stored in the storage device 2 are sequentially extracted, and if the processing of calculating the travel time adoption value has been completed for all the navigation links, the process proceeds to S. If not, the process proceeds to S22.

In S22, a traffic information link including the navigation link is searched with reference to the link correspondence table. If there is a traffic information link (S23), the DRAM 17
From 3, the travel time acquisition value AT corresponding to the traffic information link is read (S24), and the travel time adoption value GT corresponding to the navigation link is calculated from the distance ratio (S25). For example, in FIG. 9, the traffic information link LK corresponds to the navigation links LN1 and LN2, and LK, LN
It is assumed that the lengths of 1 and LN2 are L0, L1 and L2, respectively. In this case, the travel time adoption values GT1 and GT2 of the navigation links LN1 and LN2 are calculated by equation (3). Although the link correspondence table is not shown,
The brief description is as follows. A traffic information link corresponding to a navigation link can be searched using a navigation link number as a search key, and a navigation information table corresponding to a traffic information link can be searched using a traffic information link number as a search key using a traffic information link number as a key. is there.

(Equation 3)

On the other hand, if there is no traffic information link (S23 in FIG. 6), the navigation link cost CT of the navigation link is referred to from the storage device 2 (S26), and the navigation link cost CT is directly used as the travel time adoption value GT ( S27). In this way, the travel time adoption value GT for each navigation link can be obtained, and if all the navigation links are processed, the process proceeds to
A dynamic route is calculated based on the travel time adoption value GT.

7, the travel time adoption value GT of the navigation link is obtained from the current location information (S28) obtained from the vehicle location detector 14 and the destination location information (S29) specified by the driver. Is used to calculate a route (S3
0). Further, the calculated route is superimposed and displayed on the map by the display device 3 (S31), and guidance instruction information for route guidance is created (S32), and the process returns to wait for the timing of route guidance.

(4) Processing for Updating Travel Time Accuracy PT The travel time accuracy PT is set for each fixed road classification, and is updated when the vehicle travels on a traffic information link. As for this certain classification, as shown in FIG. 11, the same classification number is assigned to roads having the same road type and the same road width in the same mesh. For example, for traffic information link numbers 3 and 4, the mesh is 100
Since the road type is a national highway and the road width is 13 m or more, the classification number 2 is assigned.

The timing of updating the travel time accuracy PT will be described with reference to FIG. The vehicle is traveling on the traffic information link (link number 3 → 5 → 6 → 4). At this time,
Attention is paid to the link numbers 3 and 4 of the classification number 2. Immediately after the vehicle travels with link number 4, (n-1) th link number 3
, The travel time accuracy PT of the category 2 is updated using the information of the n-th link number 4 based on the past travel time accuracy PT ′.

The flow of the updating process is shown by S5 to S9 in FIG. That is, in S5, it is determined whether or not the vehicle has traveled on the traffic information link. This determination is made by searching for a navigation link from the traffic information link using the link correspondence table and determining whether or not the vehicle is located on the navigation link based on the position information obtained from the vehicle position detection unit 14.

At this time, the required travel time from the beginning to the end of the traffic information link is measured by the timer function of the CPU 171. This measured time is called a travel time actual measurement value MT (S6). An extreme value, etc., of the actual measured travel time MT that is not normally possible is checked, and an abnormal value having a large error is excluded (S7). Next, the latest travel time acquisition value AT corresponding to the traffic information link is read from the DRAM 173 (S8), and the travel time accuracy PT as the classification of the traffic information link is calculated by the equation (4). The calculated travel time accuracy PT updates the travel time accuracy PT of the category corresponding to the traffic information link on the travel time accuracy table in FIG. 12 (S9).

(Equation 4)

[0032]

According to the present invention, when the travel time of a new traffic information link is received, it can be evaluated based on the actual measurement value of the vehicle travel and the result of the evaluation of the travel time for each road classification. You can judge the time. As a result, the travel time with a large error is eliminated and corrected, so that an appropriate route can be calculated based on the actual traffic condition.

[Brief description of the drawings]

FIG. 1 is a simple diagram showing how a receiver mounted on a vehicle receives traffic information from a road beacon.

FIG. 2 is a table showing the contents of traffic information of a road beacon.

FIG. 3 is a block diagram of an in-vehicle dynamic route calculation device.

FIG. 4 is a diagram showing a flowchart inside an on-vehicle dynamic route calculation device.

FIG. 5 is a diagram showing a flowchart inside a vehicle-mounted dynamic route calculation device.

FIG. 6 is a diagram showing a flowchart inside a vehicle-mounted dynamic route calculation device.

FIG. 7 is a diagram showing a flowchart inside a vehicle-mounted dynamic route calculation device.

FIG. 8 is a diagram showing that a link cost of a navigation link is obtained from a traffic jam length of a traffic information link.

FIG. 9 is a diagram showing that a link cost of a navigation link is obtained from a degree of congestion of a traffic information link.

FIG. 10 is a diagram showing the update timing of the travel time accuracy PT.

FIG. 11 is a table showing meshes of traffic information links, road types, and classification numbers according to road widths.

FIG. 12 is a table showing the number of traffic information links and the travel time accuracy PT according to the classification number.

FIG. 13 is a diagram showing a schematic flowchart inside a vehicle-mounted dynamic route calculation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... In-vehicle dynamic route calculation device 2 ... Storage device 3 ... Display device 4 ... Input means 5 ... Vehicle speed sensor 6 ... Direction sensor 7 ... GPS receiver 8 ... Distance sensor 9 ... Beacon receiver 10 ... FM multiplex receiver 11 ... memory control unit 12 ... display control unit 13 ... input processing unit 14 ... vehicle position detection unit 15 ... voice control unit 16 ... dynamic route calculation processing unit 17 ... controller 171 ... CPU 172 ... SRAM 173 ... DRAM 18 ... speaker

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2C032 HB06 HB23 HB24 HC27 HC31 HD07 HD24 2F029 AA02 AB01 AB07 AB09 AC01 AC02 AC04 AC17 AC18 5H180 AA01 BB04 BB11 CC12 EE02 EE18 FF01 FF04 FF05 FF12 FF22 FF38 JJ25 FF25 FF25 FF25 FF25

Claims (3)

[Claims] 1. While taking into account a travel time included in traffic information received by a receiver, based on a road network,
A vehicle-mounted dynamic route calculation device that calculates a route from a current position to a destination obtained from a vehicle position detection unit that detects a current position of a vehicle, and displays the calculated route on a display, wherein the travel time accuracy is calculated. Travel time accuracy calculating means, based on the accuracy calculated by the travel time accuracy calculating means, travel time obtaining means for obtaining the travel time from the traffic information received by the receiver, and the travel time obtaining means An in-vehicle dynamic route calculation device that calculates a route in consideration of an acquired travel time. 2. The travel time accuracy calculation means calculates the travel time obtained by the travel time acquisition means and the travel time obtained based on the vehicle position detection means each time traffic information is received by a receiver. The in-vehicle dynamic route calculation device according to claim 1, wherein the accuracy of travel time is calculated. 3. The in-vehicle dynamic route calculation device according to claim 2, wherein said travel time accuracy calculation means calculates the travel time accuracy for each predetermined road classification.