JPH0755494A - Method of guidance and method of supplying route information - Google Patents

Abstract

PURPOSE:To contrive uniformity of a traffic flow in the case where a travel time from crossroads of a plurality of routes is calculated to instruct a vehicle by distributing the recommended routes according to the travel time of each path without narrowing recommendation routes down to one route. CONSTITUTION:A center device 2 supplies hourly changing dynamic information such as traffic jam information, construction information, recommended route information to an on-road station 1. The on-road station consists of a transmitter fixed on a pole on the side of a road 1b and an antenna 1a, time-varying information such as position information and road shape information and the dynamic information are converted into a quasi microwave and are transmitted directing to roads. The path guide method from the center device 2 does not narrow the recommended routes down to one route and is distributed according to a travel time of each route. Thereafter, in the case where the route of a long travel time and the other route of a short travel time exist, the route of the short travel time is not always recommended, according to the travel time of each route, for instance, since the routes are distributed in the time which is in inverse proportion to the travel time and they are recommended, vehicles are not converged on one route.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roadside beacon for providing traffic information to a vehicle, a route guidance method for guiding a destination of a vehicle using a roadside radio, and route information for teaching a vehicle a travel time to the destination. It relates to the providing method.

[0002]

2. Description of the Related Art Roadside beacons are installed on the side of a road,
In addition to the position coordinates of the installation location, traffic jam information, regulation information, travel time information, parking lot information, etc. are provided to the vehicle. The driver of the vehicle knows the road condition to the destination based on the information provided, and if there are two or more routes going to the same direction (for example, the route from Osaka to Nara is via the Hanna road or national road). There is a route via Route 163), and it is possible to judge which route to select, and to judge whether or not to take another loop route. Further, when the old road and the new bypass are installed in parallel, the same applies when deciding which one to select.

By the way, since it is burdensome for the driver to make the above-mentioned judgment, the center device for controlling the roadside beacons calculates travel times of a plurality of routes going in the same direction, and calculates the travel times of intersections and interchanges. A method of instructing a route that arrives at the vehicle earlier in the front or the like has been considered. According to this method, the driver of the vehicle can select the faster road without hesitation.

Since the travel time changes from moment to moment depending on the road conditions, the center device should regularly update the information.

[0005]

However, even if the center device updates the information, the same information is transmitted to many vehicles within the update time. Therefore, most vehicles having the beacon receiving function take the same action until the information is updated. Especially, if the travel time is about the same as the update time, the vacant road is crowded,
It means that the more busy road will be free
Instead, it makes the traffic flow uneven.

Therefore, an object of the present invention is to calculate the travel time from a branch point when there are a plurality of routes that lead to the same direction, and teach a recommended route to a vehicle trying to pass through the branch point. In this case, it is an object of the present invention to provide a guidance method capable of realizing uniform traffic flow. Another object of the present invention is to provide a method for realizing uniform traffic flow when there are a plurality of routes that lead to the same direction and the travel times from branch points are calculated and taught to vehicles. And to provide travel time.

[0007]

[Means and Actions for Solving the Problems]

(1) The route guidance method according to claim 1 for achieving the above object is a method of distributing recommended routes according to travel time of each route without limiting to one route. According to this method, even if there is a route with a longer travel time and a route with a shorter travel time, instead of always recommending the shorter route, it is inversely proportional to the travel time according to the travel time of each route, for example. It is recommended to distribute the time in the form. Therefore, it may happen that the route with the longer travel time is guided, so that each vehicle travels while being distributed to both routes, and is not concentrated on one route. (2) In the route guidance method according to claim 2, the recommended route is
It is a method of distributing according to the travel time of each route and the number of vehicles passing through.

According to this method, even if there is a route with a longer travel time and a route with a shorter travel time, the shorter route is not always recommended, but the travel time of each route and the number of passing vehicles are taken into consideration. Recommend the route in. For example, using a sensor (camera or ultrasonic sensor) that detects passage of a vehicle, the recommended route is distributed such that up to how many vehicles are on one route and the next several are on the other route. (3) The route information providing method according to claim 3,
It is a method of distributing and providing within the error of travel time on the route.

According to this method, there is always an error in the prediction of the travel time, so if the travel time is distributed and provided within the range of the error, the traveling route of the vehicle will be distributed. No more focusing on the route. (4) In the route information providing method according to claim 4, when the travel time is updated by regularly calculating the travel time, the travel time obtained once remains constant until the next update. It is a method of correcting and providing according to the trend tendency of travel time collected statistically, instead of treating it.

The travel time is calculated at fixed intervals in consideration of the calculation cost. However, if the travel time until the next update is provided as a fixed value, when the travel time fluctuates greatly in the short term, It will lead to incorrect guidance. Therefore, according to the present invention, it is not treated as a constant until the next update, and is corrected in accordance with the statistically collected fluctuation tendency of the travel time. Here, the "travel time fluctuation tendency" is an average fluctuation of travel time in consideration of days, days of the week, presence / absence of events, and the like.

[0011]

Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments. FIG. 2 is a schematic diagram of an information providing system using a roadside beacon, and the system is roughly divided into a roadside station 1, a vehicle-mounted device 3, and a center device 2 installed on the roadside.

The center device 2 provides the roadside station 1 with time-varying information such as traffic jam information, construction information, recommended route information (hereinafter referred to as "dynamic information"). The roadside station 1 includes a transmitter 1b fixed to a roadside pole and an antenna 1
a. The transmitter 1b uses position information, road shape information, and other information that does not change over time (hereinafter referred to as "static information").
And the dynamic information is converted into a quasi-microwave, and the antenna 1a emits the quasi-microwave radio wave toward the road.

The vehicle-mounted device 3 is mounted on a vehicle running on this road and receives radio waves radiated from the antenna 1a. The reception level of the radio wave has an electric field strength distribution that spreads around the antenna 1a. A reference level is set as the reception level, and when radio waves above this reference level can be received, the vehicle can use the signal from the roadside station 1 without being affected by noise or the like, that is, the roadside beacon. This means that the vehicle is traveling within the service area (within ± D from the installation location of the antenna 1a).

More specifically, the center device 2 is connected to the roadside station 1 through a dedicated line and provides the roadside station 1 with dynamic information. Of the dynamic information, the travel time / congestion information is edited in the center device 2 based on the external information obtained from the road administrator and the information from the database 21 as shown in FIG. To be sent to.

Among the travel time / congestion information, the time when the travel time / congestion information was created, the destination ahead on the road, the map number, and one or a plurality of destinations in the map. The link numbers that make up the recommended routes in the book, the presence or absence of congestion for each link, the degree of congestion, distance information that identifies the range of congestion in the link, the travel time of each route to the destination, the congestion It includes change forecasts, scheduled cancellation times, and so on.

[0016] The above-mentioned map means, for example, a map of a Japanese road which is equally divided into vertical and horizontal directions and has a vertical and horizontal distance of about 10km x 10km. A link is a vector that connects intersections along a road, and is specified by the coordinates of the start and end points of the link, the distance of the link, the direction in which the link passes, and the like. The method of giving the recommended route and the method of giving the travel time in the dynamic information are the subject of the present invention, which will be described later.

Since the travel time originally changes from moment to moment, it is necessary to update it regularly. The shorter the update cycle is, the better, but it cannot be shortened too much in consideration of the travel time calculation cost. Usually, the cycle is about several minutes. If the update cycle becomes long, it is preferable to interpolate the calculation time in consideration of the statistical value of the travel time fluctuation.

FIG. 4 is a graph showing the interpolation method,
The horizontal axis represents time and the vertical axis represents travel time. The travel time is updated at each update time, but after the update, the same value is not used until the next update, but the travel time is corrected according to the tendency of the fluctuation of the travel time. In FIG. 4, if it is known that the travel time tends to increase in this time zone, the updated travel time is increased according to the increase rate. If it is known that the travel time tends to decrease in this time zone, the updated travel time is reduced according to the decrease rate.

The fluctuation tendency of the travel time is
Since it varies depending on the event and the like, it goes without saying that the center device 2 must keep track of the changing tendency for each day, day of the week, event and the like. Also, when an accident or disaster occurs,
Since it does not follow such a tendency, the calculated value of the travel time is used as it is until the next update as usual without performing the above correction.

The roadside station 1 can accurately perform the original function of calibrating the antenna 1a so as to accurately perform the original function of calibrating the current position of the vehicle to the installation position of the antenna 1a when the vehicle comes directly below the installation position of the antenna 1a. It is composed of two different elements. Then, the carrier wave modulated by the first modulation method such as PSK, FSK, or ASK is divided into two parts by using the data components such as road traffic information, and the two divided signals are subjected to amplitude modulation in opposite phases to each other, thereby performing the position detection. Data is loaded and power is supplied to each antenna element so that the first modulation component has the same phase. Therefore, on the vehicle side, it is possible to extract the level variation or phase change of the amplitude modulation component to detect the vehicle position and determine the traveling direction, and to extract the first modulation component to restore the information. (Such a method is disclosed in, for example, Japanese Patent Laid-Open Nos. 2-71400 and 2-183182.
Disclosed in the publication). With this method, it is possible to provide road traffic information to vehicles in the widest possible range while maintaining the accuracy of vehicle position detection.

As shown in FIG. 5, the vehicle-mounted device 3 includes a vehicle information receiving device 12, a road map memory 17 for storing road map data, and a memory drive 16 for reading the stored data from the road map memory 17. And reading a road map within a predetermined range, processing road traffic information obtained from the vehicle information receiving device 12, creating guide display data for guiding the vehicle, controlling the voice guiding device 14, road map and recommending. The navigation controller 13 performs various controls such as control of the display device 15 that displays the route to be performed.

The vehicle information receiving device 12 receives, demodulates and processes radio waves from the roadside station 1 installed on the ground. As shown in FIG.
A mixer 22 that mixes the signals from the local oscillator 23, an intermediate frequency amplifier 24, a data demodulator 25 that demodulates the data included in the intermediate frequency signal, and a data processor 26 that processes the demodulated data. Have.

The data demodulation section 25 is for demodulating the FSK-modulated or PSK-modulated data signal included in the intermediate frequency signal. The data processing unit 26 detects the road traffic information from the on-road station 1 obtained from the data demodulation unit 25 and performs processing for transmitting the road traffic information to the navigation controller 13. The navigation controller 13 creates image data based on the content of the road traffic information obtained from the data processing unit 26 and causes the display device 15 to display the image data.

In particular, when the travel time / congestion information is obtained, the following processing is performed. First, the road map data centering on the vehicle position obtained through the roadside station 1 and the like is acquired through the memory drive 16, the vehicle position data and the road map data are given to the display device 15, and the road map and the road map are displayed. The vehicle current position mark and is generated and displayed.

Further, the navigation controller 13
Edits the recommended route display data based on the route to the destination included in the obtained travel time / congestion information.
Table 1 shows an example of the format of the recommended route display data.

[0026]

[Table 1]

In this table, the provided time is the time when the travel time / congestion information was created, the destination is the name of the place ahead of the road, the number of maps is the number of maps including the recommended report, The number of links in the map is the number of links to which recommended information is given in each map. The navigation controller 13 draws the display coordinate sequence based on the recommended route display data edited in this way. The drawn coordinate sequence is superimposed on the road map and displayed as a recommended route on the display device 15.

In the above, the recommended route is displayed together with the road map, but it is also possible to simply display the road branching direction on the screen. In this case, Table 2 shows an example of the format of the branch direction display data.

[0029]

[Table 2]

In this table, the number of branch information is the number of branches at the previous intersection given from the roadside station 1, and the branch number is approximated by dividing the branch angle of the previous intersection into 12 equal to 360 ° as shown in FIG. The recommended flag is a number from 0 to 3 indicating the degree to which each branch can be recommended, 0 means unknown, 1 means recommended, 2 means semi-recommended, and 3 means not recommended. actually,
It is displayed in different colors according to the distinction of 1-3. For example,
"Recommended" is displayed in blue, "Semi-recommended" is displayed in yellow, and "Deprecated" is displayed in red.

FIG. 8 shows an example of a simple display of the branching direction of the road. It shows that the destination "Kyoto" can be reached in 30 minutes by turning left diagonally, 40 minutes by going straight, 60 minutes by turning right, and the route turning left diagonally. Is displayed in blue indicating “recommended”, the straight route is displayed in yellow indicating “semi-recommended”, and the route turning right is displayed in red indicating “not recommended”.

Next, several methods for giving a recommended route and giving a travel time from the center device 2 will be described. (A) Method to fix recommended route to 1 This is a conventional method, and the route with the least travel time is 1
This route is selected, and this route is given from the center device 2 to the on-road station 1 as a recommended route. Therefore, each vehicle that receives the radio wave of the roadside station 1 acts based on the same information. This method has no problem when the distance to the destination is very long or when the update period of the dynamic information is very short. (B) Method of distributing recommended routes according to the travel time of each route When there is a route with a longer travel time and a route with a shorter travel time, it is recommended not to recommend only the shorter route, but the recommended time Is a method of time distribution in a form inversely proportional to the travel time of each route.

For example, the route R with the longer travel time₁Travel
Time is T₁, Shorter route R₂Travel time is T₂Is
Then, the route R₁T is the recommended time ratio₂/ (T₁
+ T ₂), Route R₂T is the recommended time ratio₁/ (T₁
+ T₂). Route R₁Travel time
20 minutes, route R₂Let's assume that the travel time is 10 minutes
And the route R₁Is recommended for 1 minute, then route R₂Is recommended for 2 minutes
Continue the cycle of (C) Travel time and vehicle passage of each recommended route
Distributing according to the number of vehicles The number of vehicles passing through the road is set by installing a camera etc. on the road
Thailand that counts one and switches the recommended route
This is a method of judging the minging by the count number.

For example, the route R with the longer travel time₁Journey
Line time T₁, Shorter route R₂Travel time is T₂And
Then, T₂When counting the number of units proportional to
Route R₂Switch the recommended route to₁Is proportional to
Route R when counting ₁Switch the recommended route to
Get Route R₁Travel time of 10 minutes,
Route R₂If the travel time is 5 minutes, the first 5
For route R₁Is recommended, and after passing 5 units to the next 10 units
Is route R₂Is recommended. (D) Travel time is the range of travel time error on the route.
There is an error in the travel time originally due to the method of providing it in a dispersed manner. Route R₁When traveling
Interval T₁, Route R₂Travel time T₂(T₁> T₂) Error
(Standard deviation) is σ₁, Σ₂Then, consider the error
If you think about it, the route that should take a long time Route R₁Traveling
Route R which should have shorter travel time₂I will drive
It may arrive sooner.

Therefore, for example, as shown in FIG.
₁Draw the probability distribution of travel time of (for example, Gaussian distribution),
Time T₁, T₁± σ₁/ 2, T₁± σ₁Probability of
Degree P (T₁−σ₁), P (T₁−σ₁/ 2), P
(T₁), P (T₁+ Σ₁/ 2), P (T₁+ Σ₁)
I'll think about it. Furthermore, the route R₂The travel time probability distribution of
Drawing time T₂, T₂± σ₂/ 2, T₂± σ₂Sure in
Rate density P (T₂−σ₂), P (T₂−σ₂/ 2), P
(T₂), P (T₂+ Σ₂/ 2), P (T₂+ Σ₂)
I'll think about it. Route R₁About travel time of T
₁Probability density P (T₁−σ₁) Proportional to
Travel time T₁−σ₁And the probability density P
(T₁−σ₁/ 2) Travel time T times proportional to₁−
σ₁// 2, and the probability density P (T₁) Proportional to
Only travel time T₁And the probability density P (T₁+ Σ₁/
Travel time T times proportional to 2)₁+ Σ₁Offer / 2
And the probability density P (T₁+ Σ₁) Traveled a number of times proportional to
Time T₁+ Σ₁I will provide a. Route R ₂About travel time
But evenly T₂But the probability density is
Degree probability density P (T₂−σ₂), P (T₂−σ₂/ 2),
P (T₂), P (T₂+ Σ₂/ 2), P (T₂+ Σ₂)
Providing travel time according to.

[0036] Consequently, in the case of FIG. 1 provides a T ₁ - [sigma] ₁ as the travel time of the route R _{1, and, T 2, T 2 + σ} 2/2 as the travel time of the route R _2, or T ₂ There is a probability of providing + σ ₂ . T as travel time for route R _1
1− σ ₁ is provided, and the travel time of the route R ₂ is T ₂ , T
₂ + _{σ 2/2,} or when providing T ₂ + σ _2, since the magnitude relationship of the travel time is reversed, the path R ₁ you believe long travel time is recommended, otherwise, the route R ₂ Will be recommended. Therefore, the route R ₂
However, since the route R ₁ is guided to some vehicles, the concentration of traffic can be avoided.

[0037]

As described above, according to the inventions of claims 1 and 2, when there are a plurality of roads leading to the same direction, the travel time from each branch point is calculated and the recommended route is set to the branch point. When teaching and guiding to a vehicle that is about to pass through, the recommended routes are not limited to one and are distributed and the teaching is guided. Therefore, each vehicle does not always take the same action. Therefore, when the distance to the destination is short or when the travel time update period is long, the adverse effect of concentrating on one of the routes is eliminated, and the traffic can be made uniform.

According to the third aspect of the present invention, the travel time is distributed and provided within the error range of the travel time of the route. Therefore, when there are a plurality of routes, the route having the longer average travel time is provided. It is possible that the travel time provided is shorter than the travel time provided for the route with the shorter average travel time. As a result, the traveling route of the vehicle is also distributed, and the vehicle does not concentrate on one route.

According to the invention described in claim 4, the travel time obtained once is not treated as a constant until the next update, and is corrected according to the statistically collected fluctuation tendency of the travel time. Therefore, the effect that the route can be guided based on the travel time that is more practical is obtained.

[Brief description of drawings]

FIG. 1 is a graph illustrating a method of distributing travel times based on a probability distribution of travel times of respective routes.

FIG. 2 is a schematic diagram of an information providing system using a roadside beacon.

FIG. 3 is a block diagram showing functions of a center device.

FIG. 4 is a graph showing a method of interpolating travel time when the travel time update cycle is long.

FIG. 5 is a schematic block diagram showing the contents of an in-vehicle device.

FIG. 6 is a schematic block diagram showing the contents of a vehicle information receiving device.

FIG. 7 is a diagram showing branch angles at intersections and the like.

FIG. 8 is a screen display diagram showing an example in which a branching direction of a road for reaching a destination is simply displayed.

[Explanation of symbols]

 1 Road station 2 Center device 3 In-vehicle device

Claims (4)

[Claims] 1. A route guidance method for calculating a travel time from a branch point and teaching and guiding a recommended route to a vehicle trying to pass through the branch point when there are a plurality of routes leading to the same direction, A route guidance method characterized by distributing recommended routes according to the travel time of each route. 2. A route guidance method for calculating a travel time from a branch point and teaching and guiding a recommended route to a vehicle trying to pass through the branch point when there are a plurality of routes leading to the same direction, A route guidance method characterized in that recommended routes are distributed according to the travel time of each route and the number of vehicles passing through. 3. When there are a plurality of routes that lead to the same direction, the travel time from the branch point is calculated, and the travel time is calculated in the route information providing method for teaching the vehicle trying to pass through the branch point. A method for providing route information, which is provided by dispersing the travel time within an error range of the route. 4. When there are a plurality of routes that lead to the same direction, the travel time from each branch point is calculated, and the travel time is calculated in a route information providing method for teaching a vehicle trying to pass through the branch point. A route information providing method characterized in that the travel time is obtained periodically, and the travel time obtained once is corrected and provided according to the statistically collected fluctuation tendency of the travel time until the next update.