JP5910514B2 - Route distribution system - Google Patents

Description

  The present invention relates to a route distribution system.

  As a conventional traffic volume, a system that collects traffic information such as traffic jams via a traffic infrastructure such as an infrared sensor or an optical beacon provided on the roadside is known. The traffic information here is travel time or average speed passing through the road.

  Furthermore, in recent years, a probe traffic information service that collects a lot of traffic information acquired by the vehicle itself as a sensor and provides the result to the in-vehicle device has attracted attention. In this probe traffic information service system, a vehicle collects history data (probe information) such as position information and time information on which the vehicle has traveled, and passes it to a traffic information center via a communication device such as a mobile phone or a radio. Uplink. A vehicle that collects such history data is called a probe car. In the traffic information center, probe information uplinked from each vehicle is converted into road link traffic information and provided to each in-vehicle device via a communication device.

  As a background art in the technical field of the present invention, there is JP-A-2004-29871 (Patent Document 1). This Patent Document 1 describes that reliability (accuracy) is taken into account in addition to information based on the newness of information as an index for properly using two estimated travel times.

JP 2004-29871 A

  In the technology described in Patent Document 1, after collecting traffic information from a plurality of information sources, considering the accuracy of each information source, a plurality of traffic information is merged into one traffic information. Since the characteristics differ for each information source of traffic information, when the traffic information is simply focused on only the accuracy and the route search is performed using the result, there arises a problem that the route of the search result is not stable.

  For example, the traffic information from the traffic infrastructure can be always collected by a roadside sensor, so that the travel time can always be output. However, it is known that there are regional differences in the accuracy of this travel time.

  On the other hand, the probe traffic information has a characteristic that the travel time can be output only when the probe car travels. Furthermore, since the probe car is affected by the road environment around the vehicle such as a road signal, it is known that the travel time to be output varies.

  Considering the characteristics of each traffic information source as described above, the accuracy of the probe traffic information is relatively improved in an area where the accuracy of the traffic information from the traffic infrastructure is poor. When the traffic information is merged only with accuracy, the travel time of the probe traffic information is easily reflected. At this time, if the travel time of the probe traffic information is shortened, the road on which the probe traffic information is distributed is easily selected during the route search. However, since probe traffic information varies widely, the searched route becomes sensitive to changes in travel time of traffic information. In other words, since the accuracy and variation of the characteristics of traffic information are different, when a route search is performed using traffic information fused only with accuracy, the searched route is easily changed from time to time, and the route search result becomes unstable.

  Therefore, the present invention aims to provide a stable route search result using the fused traffic information by merging a plurality of traffic information in consideration of the characteristics of the information source of each traffic information. And

In order to solve the above-described problem, in the present invention, in a route distribution device that searches for a route based on an instruction of a departure point and a destination from a terminal device, information on a departure point and a destination from the terminal device, A receiving device that receives a plurality of traffic information from a plurality of information sources, and obtains an error and variation of the traffic information for each information source, and creates a fusion coefficient that is a weight when fusing the traffic information from the error and variation. A fusion coefficient creation device, a created fusion factor, a recording device that stores map information, and the received traffic information; a fusion device that fuses current traffic information using the created fusion factor; and a route calculation unit for calculating a route using the fused traffic information fusion device, a transmitter for transmitting the calculated route to the requesting terminal device, errors or loose the current traffic information received by the receiving device Using come, and a fusion coefficient correcting means for correcting the fusion factor, the fusion device for fusing traffic information using a fusion coefficients corrected by the fusion factor correcting means.

  According to the present invention, errors and variations are evaluated for each traffic information source, and a plurality of traffic information is merged by obtaining a fusion coefficient from these errors and variations, so that traffic information with large variations is preferentially used. It is possible to provide a stable route by suppressing the use and calculating the route using the fused traffic information.

It is a block diagram which shows the whole structure of the route delivery system which concerns on embodiment of this invention. It is an example of the data format of traffic information. It is an example of the data format of departure place and destination information. It is an example of the data format of fusion coefficient information. It is an example of the data format of infrastructure information source error information. It is an example of the data format of map information. It is a processing flow of fusion coefficient information creation in the fusion coefficient creation device 130. It is an example of the data format of statistical traffic information. It is a processing flow of infrastructure information source error information creation in the fusion coefficient creation device 130. It is a processing flow of the fusion coefficient correction apparatus 140. This is the format of route data. It is an example of a display screen in the display device 240. It is a processing flow in the display apparatus 240. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an overall configuration of a route distribution system including a route distribution device 100 and a terminal device 200 according to an embodiment of the present invention. 1 includes a receiving device 110, a recording device 120, a fusion coefficient creation device 130, a fusion coefficient correction device 140, a fusion device 150, a route calculation device 160, and a transmission device 170. The terminal device 200 includes a transmission device 210, a reception device 220, an input device 230, and a display device 240.

  The route distribution device 100 and the terminal device 200 are connected by a receiving device 110, a transmitting device 170, a transmitting device 210, and a receiving device 220. These devices may be a mobile phone, a wireless LAN module, a PDA (Personal Digital Assistance), or a modem integrated with the route distribution device 100 and the terminal device 200.

  The receiving device 110, the fusion coefficient creation device 130, the fusion coefficient correction device 140, the fusion device 150, the route calculation device 160, and the transmission device 170 are stored in a RAM, by a microprocessor (not shown) mounted in the route distribution device 100. This is realized by executing software stored in a ROM or the like. Similarly, the transmission device 210, the reception device 220, the input device 230, and the display device 240 are executed by software stored in RAM, ROM, etc. by a microprocessor (not shown) mounted on the terminal device 200. Is realized.

  First, the configuration of the route distribution device 100 will be described. The receiving device 110 of the route distribution device 100 receives traffic information from a plurality of information sources such as servers provided outside the route distribution system. The received traffic information is stored in the recording device 120 and provided to the fusion coefficient correction device 140 and the fusion device 150.

  The plurality of information sources can be divided into infrastructure information sources installed in the infrastructure such as road sensors, roadside sensors, and loop sensors, and probe information sources using probe cars as information sources. The received traffic information includes, for example, road travel time information using a roadside sensor as an information source and vehicle travel time information using a probe car as an information source.

  In addition, the reception device 110 receives departure / destination information from the transmission device 210 of the terminal device 200. The received departure / destination information is provided to the route calculation device 160. The data format of information received by the receiving device 110 will be described later.

  The recording device 120 is a recording device such as a hard disk or a flash memory, and fusion coefficient information for fusing traffic information from a plurality of information sources received by the receiving device 110 with traffic information from the plurality of information sources, Infrastructure information source error information and map information are recorded as characteristic information related to traffic information from infrastructure information sources.

  The fusion coefficient information is information relating to the fusion coefficient, such as errors and standard deviations of information sources. Since the present invention generates reliable traffic information by fusing various types of traffic information, this fusion coefficient may be considered as the reliability of the traffic information source, and the greater the value of this fusion coefficient, the higher the reliability. Is expensive. The fusion of a plurality of traffic information is calculated by placing importance on traffic information with high reliability. In the present invention, the reliability of the traffic information is defined by an error and a standard deviation. The error is an index indicating how much deviation is present compared to the true traffic information. The standard deviation is an index representing the degree of variation in traffic information. For this reason, the smaller the error and the standard deviation, the lower the reliability of the traffic information. Therefore, it is necessary to calculate the fusion coefficient from the error and the standard deviation so that the fusion coefficient becomes smaller as the traffic information error is larger and the standard deviation is larger. The infrastructure information source error information is information relating to an error in traffic information for each speed band of the infrastructure information source. Details of the recording device 120 will be described later.

  The fusion coefficient creation device 130 creates fusion coefficient information and infrastructure information source error information using the traffic information from each information source recorded in the recording device 120, and writes it into the recording device 120. These processes are executed at regular intervals such as one month or one year. Details of the fusion coefficient creation device 130 will be described later.

  The fusion coefficient correction device 140 corrects the fusion coefficient written in the recording device 120 using the current traffic information received by the reception device 110 and provides the correction to the fusion device 150. This process is a process for reflecting the current traffic information on the fusion coefficient generated from the past traffic information from each information source recorded in the recording device 120. By reflecting the current traffic information in the fusion coefficient, it is possible to fuse the traffic information considering the error and variance in the current traffic information. The fusion coefficient correction device 140 will be described later.

  The fusion device 150 uses the current traffic information received by the reception device 110 and the fusion coefficient corrected by the fusion coefficient correction device 140 to merge the traffic information collected from a plurality of information sources into one traffic information, This is provided to the route calculation device 160. Details of the fusion device 150 will be described later.

  The route calculation device 160 receives the map information recorded in the recording device 120, the traffic information from the fusion device 150, and the departure / destination information from the reception device 110 as input, and searches for an existing route such as the Dijkstra method. The route from the departure point to the destination is calculated using an algorithm, and information about the route is provided to the transmission device 170.

  The transmission device 170 transmits information regarding the route calculated by the route calculation device 160 to the reception device 220 of the terminal device 200. The data format of the information to be transmitted will be described later.

  Next, the configuration of the terminal device 200 will be described. The transmission device 210 of the terminal device 200 transmits the information regarding the departure point and destination input from the input device 230 to the reception device 110 of the route distribution device 100.

  The receiving device 220 receives information about the route transmitted from the transmitting device 170 of the route distribution device 100 and provides the information to the display device 240. The data format received by the receiving device 220 is the same as the data format transmitted from the transmitting device 170.

  The input device 230 receives departure / destination information that the user inputs to the terminal device 200 through a user interface such as a remote controller, and provides the information to the transmission device 170. When entering departure / destination information, the user searches for a POI (Point Of Interest) that is the departure or destination, using information such as departure and destination addresses, categories, and telephone numbers as keys. To set. The POI is information regarding points such as store information and facility information. The departure place may be acquired from a sensor such as a GPS (not shown) mounted on the terminal device 200 using an existing method.

  The display device 240 is a liquid crystal display or the like, and displays the route information received by the receiving device 220. Details of display examples on the display device 240 will be described later.

  Details of the data format of the information received by the receiving apparatus 110 will be described. As described above, the receiving device 110 receives traffic information from a plurality of information sources such as a server and departure / destination information from the transmission device 210 of the terminal device 200. FIG. 2 is an example of a data format of traffic information. In the data format shown in FIG. 2, in addition to the speed information as traffic information, the time when this traffic information was measured, the mesh ID and link ID as information for identifying the road where the traffic information was measured, and the traffic being transmitted It consists of a traffic information ID for identifying and identifying information and an in-vehicle ID. Since the traffic information of the probe information source receives the traffic information for each vehicle, the information for identifying the vehicle providing the traffic information is the in-vehicle ID. This in-vehicle ID is an ID of a device that identifies a terminal device or a mobile phone mounted on the probe car. In the case of traffic information from an infrastructure information source, the vehicle ID information is not used.

  The map information is divided into meshes based on latitude and longitude, and the road is divided into mesh units and managed. The mesh ID is information for identifying the mesh in which the corresponding road is managed, and the link ID is an ID for identifying the road on which the traffic information is collected for each mesh.

  The traffic information ID is an ID for identifying an information source of traffic information received by the receiving device 110. For example, traffic information measured from a roadside sensor is ID “0”, traffic information measured by a general vehicle driven by a general driver is ID “1”, and traffic information measured by a logistics vehicle such as a taxi or a truck is ID “0”. 2 ”. The speed data is an average speed measured when passing the road. Moreover, it can be determined by this traffic information ID whether the traffic information is an infrastructure information source or a probe information source.

  FIG. 3 shows a data format of departure / destination information. The data format shown in FIG. 3 includes an in-vehicle ID for identifying the terminal device 200 that has transmitted the departure place / destination information, and information on the departure place and the destination. The information of the departure point and the destination is information that can specify a position such as a node ID of a node constituting a link (road segment) in map information and a mesh ID of a mesh including the node. The information on the departure point and the destination may be information on latitude and longitude corresponding to the point.

  Details of the recording apparatus 120 will be described. The recording device 120 includes fusion coefficient information, infrastructure information source error information, and map information.

  FIG. 4 is an example of the data format of the fusion coefficient information recorded in the recording device 120. The fusion coefficient information stores, for each traffic information ID, an error, a standard deviation, and a fusion coefficient calculated by the fusion coefficient creation device 130 based on the traffic information recorded in the recording device 120 for each information source. Such fusion coefficient information is created for each road link or for each mesh. Using the traffic information ID as a key, the error, standard deviation, and fusion coefficient of the information source of the traffic information in the corresponding road link or mesh are extracted.

  FIG. 5 is an example of the data format of the infrastructure information source error information of the recording device 120. The infrastructure information source error information stores an error for each speed range of the infrastructure traffic information. These are calculated by the fusion coefficient creation device 130. Similar to the fusion coefficient information, these fusion coefficient information is also created for each road link or each mesh.

  FIG. 6 is an example of the data format of the map information of the recording device 120. As described above, the map information is divided into mesh units divided into meshes based on latitude and longitude, and roads are managed. Each road link (segment) constituting the road is mesh-road. Stored in link order. The information indicating the road link includes a link ID for identifying each, a start point and an end point information of each road link, a road type, a link length, and a regulated speed.

  Each road link has a direction, and basically corresponds to the traveling direction of the vehicle based on regulations. The direction and position on the map can be specified by the information of the start point and end point of the road link. Each of the start point and end point of the road link includes a node representing a point, and the information of the start point and the end point includes a node ID for identifying the node, and latitude and longitude information representing the position of the node, respectively.

  The road type is information indicating the type of road represented by each road link. For example, “0” if the road represented by the road link is an intercity highway, “1” if it is an intracity highway, “2” if it is a national road, “3” if it is any other road, etc. Defined. The other road is, for example, a narrow street. In addition, when national roads are divided by grade, information may be assigned according to the grade.

  The link length is information representing the distance along the road link from the start point to the end point. The regulated speed is information representing a speed limit set on the road of the corresponding road link.

  Details of the fusion coefficient creation device 130 will be described. First, a processing flow for creating fusion coefficient information to be recorded in the recording device 120 will be described with reference to FIG. Here, the average error and standard deviation of the infrastructure information source and the probe information source are calculated, and then the fusion coefficient is calculated.

  First, in step S100, it is determined whether or not processing has been completed for all road links of traffic information stored in the recording device 120. When the process for all road links is completed (Yes in S100), the fusion coefficient information creation process is terminated. If the processing has not been completed for all road links yet (No in S100), one road link that has not been processed is selected, and the process proceeds to step S110.

  In step S110, statistical traffic information is created using the traffic information from each information source for the unprocessed road link selected in step S100. An example of the data format of this statistical traffic information is shown in FIG. The statistical traffic information shown in FIG. 8 represents the statistical traffic information of a certain road link, and for each time zone obtained by dividing one day at a predetermined time interval, the average value of the travel time measured by the corresponding road link and Consists of standard deviation. The time zone is a predetermined time width, and is defined as, for example, 1 hour in the example shown in FIG. Specifically, the traffic information for each road link is classified for each predetermined time zone, and the average value and standard deviation of the travel time are calculated. After calculating the statistical traffic information, the process proceeds to step S120.

  In step S120, the traffic information error of the infrastructure information source is evaluated using the statistical traffic information obtained in step S110. Here, the information of the probe car that actually traveled on the road is correct as the traffic information at the time when the probe car data was collected, and the traffic information of the probe information source varies due to statistical processing by collecting multiple samples. The statistical traffic information of the probe information source is treated as a true value, and the error of the traffic information of the infrastructure information source is evaluated for each time zone.

  The error Et of the infrastructure information source in the time zone t in the road link to be evaluated is calculated from the travel time Tpt of the statistical traffic information of the probe information source and the travel time Tvt of the statistical traffic information of the infrastructure information source in the time zone t of the road link. , (Equation 1).

Et = (Tvt−Tpt) / Tpt (Equation 1)
After calculating the infrastructure information source error Et for all time zones t, the process proceeds to step S130.

  In step S130, an error in the traffic information of the probe information source is set. The error of the traffic information of the probe information source is set to a constant value and is written as the error of the probe information source in the fusion coefficient information of the recording device 120. As the constant value set as the error, since the true value is used as the statistical traffic information of the probe information source in step S120, the error of the traffic information of the probe information source may be zero. When the traffic information of the probe information source is separately evaluated, an error value based on the evaluation result is input.

  In step S140, the standard deviation of the probe information source, the error of the infrastructure information source, and the standard deviation in the fusion coefficient information for each information source shown in FIG. 4 are stored. The standard deviation of the probe information source and the standard deviation of the infrastructure information source are the average values of the standard deviations of all time zones in the statistical traffic information for each road link created in step S110. Further, the error of the infrastructure information source is the average value of the error in each time zone calculated in step S120. The calculated standard deviation of the probe information source and the error and standard deviation of the infrastructure information source are stored in the fusion coefficient information of the recording device 120.

  In step S150, the fusion coefficient is calculated using the error and standard deviation for each traffic information source stored in the recording device 120 as fusion coefficient information. The fusion coefficient represents the reliability of the traffic information source, and the greater the value, the higher the reliability. Therefore, it is necessary to calculate the fusion coefficient from the error and the standard deviation such that the larger the error and the larger the standard deviation, the smaller the fusion coefficient. For example, the fusion coefficient is calculated by (Formula 2), where Z is the fusion coefficient of the information source, E is the error E, and S is the standard deviation.

Z = 1 / (α × E + β × S) (Formula 2)
Here, the coefficients α and β are coefficients that determine the weight of the error and the standard deviation. For example, when α is larger than β, this means that the error is weighted more than the standard deviation. When β is 0, the fusion coefficient is calculated considering only the accuracy, and when α is 0, the fusion coefficient is calculated considering only the standard deviation. Predetermined values may be adopted as the coefficients α and β, or values input by the server administrator may be used.

  For example, if you want to place more emphasis on shorter travel times than variations in travel times, the smaller the error in the combined travel time, the greater the probability of finding the shortest route, and the expected travel time. The coefficient α is set to be larger than the coefficient β because it is considered to be shorter. On the contrary, when the variation in travel time is suppressed and the emphasis is on obtaining a stable route, the coefficient β is set larger than the coefficient α. This is set in consideration of the quality of the route obtained as the final route search result by the administrator of the route distribution device 100. After calculating the fusion coefficient, the value is set to the fusion coefficient of the fusion coefficient information of the recording device 120, and the process returns to step S100.

  Next, a processing flow for creating infrastructure information source error information of the recording apparatus 120 will be described with reference to FIG. It is known that the traffic information from the infrastructure information source has different accuracy of the collected traffic information depending on the area where the road link exists and the speed range of the traveling vehicle. For example, in some areas, the accuracy of information when there is a traffic jam is low, but the accuracy of information when traffic is flowing smoothly may be high.

  Therefore, the fusion coefficient correction device 140 evaluates the traffic information error of the current infrastructure information source, and associates the error with the speed range of the traveling speed for the road link where the roadside sensor is installed as shown in FIG. The table is prepared in advance and recorded in the recording device 120 as infrastructure information source error information.

  In the process for creating the infrastructure information source error information, in step S200, it is determined whether or not the process has been completed for all road links of the traffic information recorded in the recording device 120. When the processing of all road links is completed (No in S200), the infrastructure information source error information creation processing is terminated. If all the road links have not been processed yet (Yes in S200), one unprocessed road link is selected, and the process proceeds to step S210.

  In step S210, statistical traffic information of each information source of the infrastructure information source and the probe information source is created for each speed band for the target road link. This classifies the travel time in the statistical traffic information for each time zone for each speed band, calculates the average value, and creates the statistical traffic information for each speed band for each time zone. The classification for each speed band means that the travel time is divided into predetermined values, for example, in increments of 10 km / h such as 10 km / h to 20 km / h.

  Next, in step S220, the infrastructure information source error is calculated for each speed band using the statistical traffic information for each speed band obtained in step S210. Here, as in step S120, the statistical traffic information of the probe information source is set to a true value, and error evaluation is performed for each speed band in each time zone. The error Ew of the infrastructure information source in the velocity band w to be evaluated is expressed by using the average travel time Tpw in the statistical traffic information of the probe information source and the average travel time Tvw in the statistical traffic information of the infrastructure information source (formula Calculate according to 3).

Ew = (Tvw−Tpw) / Tpw (Equation 3)
As Tpw and Tvw, the values obtained for each speed band in step S210 are used. After calculating the error for each speed band for all time zones, the process returns to step S200.

  Details of the fusion coefficient correction device 140 will be described. This corrects the fusion coefficient in consideration of errors and variations in the current traffic information received by the receiving device 110. The fusion coefficient information of the recording device 120 is information created from the traffic information accumulated in the recording device 120 as described above. By adding information based on the current traffic information to this, a fusion coefficient that matches the current traffic status can be created. To correct the fusion coefficient, the infrastructure information source error obtained from the current traffic information and the standard deviation of the probe information source are used.

  The error of the infrastructure information source in the current traffic information is calculated using the traffic information of the infrastructure information source of the receiving device 110 and the infrastructure information source error information of the recording device 120. The standard deviation of the probe information source in the current traffic information is calculated using the traffic information of the probe information source of the recording device 120. As the standard deviation of the infrastructure information source and the error of the probe information source, values stored in the fusion coefficient information of the recording device 120 are used.

  The processing flow of the fusion coefficient correction device 140 will be described with reference to FIG. In step S300, it is determined whether all the road links targeted by the traffic information received by the receiving device 110 have been processed. If all have been processed (Yes in S300), the process ends. If a road link that has not yet been processed remains (No in S300), one of them is selected and the process proceeds to step S310.

  In step S310, the traffic information error from the infrastructure information source received by the receiving apparatus 110 is acquired. Specifically, the infrastructure information source error information of the recording device 120 is searched using the speed range corresponding to the travel time of the traffic information of the current infrastructure information source of the road link selected in step S300 as a key, and the corresponding error is determined. get.

  In step S320, the standard deviation of the current traffic information from the probe information source received by the receiving apparatus 110 for the road link selected in step S300 is calculated.

  Step S330 uses the error based on the current traffic information from the infrastructure information source acquired in Step S310 and the standard deviation of the current traffic information from each probe information source calculated in Step S320, and uses the recording device 120. The fusion coefficient in the fusion coefficient information is corrected, and the result is provided to the fusion device 150. The fusion coefficient to be corrected is acquired from the fusion coefficient information of the recording device 120 every time correction is performed. Thereafter, the process proceeds to step S300.

  The fusion coefficient is corrected by, for example, replacing the error and standard deviation in (Equation 2) with the values calculated in steps S310 and S320 and calculating the fusion coefficient again. Or, for the infrastructure information source, if the error Ev2 of the infrastructure information source based on the current traffic information is used, the corrected fusion coefficient Zv2 from the error Ev1 and the fusion coefficient Zv1 acquired from the fusion coefficient information of the recording device 120 is ( Equation 4) is obtained.

Zv2 = Zv1 * (1- (Ev2-Ev1)) (Formula 4)
This is because the term (Ev2−Ev1) in (Equation 4) is smaller than 0 when the traffic information error in the current infrastructure information source is smaller than the error recorded in the recording device 120. Therefore, the corrected fusion coefficient Zv2 is corrected to a value larger than the fusion coefficient Zv1 before correction. Conversely, when the traffic information error in the current infrastructure information source is large, the corrected fusion coefficient Zv2 is corrected to a value smaller than the uncorrected fusion coefficient Zv1. The correction of the fusion factor using the current standard deviation of the probe information source is calculated in the same way.

  Thus, by correcting the fusion coefficient using the current traffic information, the error and standard deviation of the current traffic information can be added to the fusion coefficient calculated by a statistical method. For example, consider a case where the standard deviation of the probe information source in the fusion coefficient information of the recording device 120 is small as a result of calculation by a statistical method. At this time, in the current traffic information, it is assumed that travel time varies due to a sudden event such as an accident occurring on an actual road. In this case, the fusion coefficient is corrected in consideration of the standard deviation of the current traffic information, so that the specific gravity of the traffic information from the probe information source in the traffic information of this road where the accident has occurred becomes small, and the travel time However, the specific gravity of infrastructure information sources will increase. Thus, by using the fusion coefficient corrected in accordance with the current traffic information, the fused traffic information becomes more reliable.

  Details of the fusion device 150 will be described. The fusion device 150 uses the current traffic information received by the reception device 110 and the fusion coefficient corrected by the fusion coefficient correction device 140 to merge the traffic information from a plurality of information sources into one traffic information. The merged traffic information is provided to the route calculation device 160. There are two types of fusion of traffic information: fusion of travel time and fusion of standard deviation.

  If the fusion coefficient of the probe information source is Zp, the travel time is Tp, the fusion coefficient of the infrastructure information source is Zv, and the travel time is Tv, the travel time Tm of the fused traffic information can be calculated by (Equation 5). It is assumed that the fusion coefficients Zv and Zp are the fusion coefficients Zv2 and Zp2 corrected by the fusion coefficient correction device 140.

Tm = (Zp × Tp + Zv × Tv) / (Zp + Zv) (Formula 5)
If the fusion coefficient of the probe information source is Zp, the standard deviation is Sp, the fusion coefficient of the infrastructure information source is Zv, and the standard deviation is Sv, the standard deviation Sm of the fused traffic information can be calculated by (Equation 6).

Sm = (Zp × Sp + Zv × Sv) / (Zp + Zv) (Formula 6)
Here, as the standard deviation of the probe information source, the value calculated in step S320 described above is used. As the standard deviation of the infrastructure information source, a value included in the fusion coefficient information of the recording device 120 is used.

  The travel time Tm and the standard deviation Sm for each road link are output to the route calculation device 160 as the combined traffic information as described above, and reflected in the route search in the route calculation device 160.

  Details of the route calculation device 160 will be described. The route calculation device 160 receives the map information of the recording device 120, the traffic information from the fusion device 150, and the departure / destination information set from the terminal device 200 received by the reception device 110, and inputs an existing route search. A route from the departure point to the destination is calculated using a technique (such as the Dijkstra method) and provided to the transmission device 170. At this time, the travel time of the road link provided from the fusion device 150 is used as a cost, and the route from the departure point to the destination is calculated so that the sum of the cost of the road link constituting the route becomes the minimum cost. A plurality of routes may be calculated under conditions such as general road priority and distance priority.

  The calculated route information is provided to the transmission device 170. An example of the format of the route data provided at this time is shown in FIG. The route data is required for the road links corresponding to the position information of the starting point and the destination, that is, the link links constituting the road links at both ends of the route and the road links as the start and end points of the route, and the travel of the route. It consists of travel time and its standard deviation. The travel time information is the total travel time of each link train in the route data. The standard deviation information S is calculated by (Expression 7), where Si is the standard deviation of the link string i. Here, the standard deviation information S is the square root of the sum of squares of the standard deviation Si of each link in the link sequence of the route.

S = √ (ΣSi ² ) (Expression 7)
The transmission device 170 distributes the route information to the reception device 220 of the target terminal device 200 using the data format of the route information in FIG.

  The display device 240 expands the route information received by the receiving device 220 and displays the route information on a device such as a liquid crystal display that constitutes the display device 240. FIG. 12 is an example of a screen displayed when a plurality of routes (route A, route B, route C) are transmitted from the transmission device 170. The text 121 is a name for distinguishing each route, and is given for convenience in the terminal device 200. Icon 122 represents the departure place, and icon 123 represents the destination. The length of the straight line 124 connecting these icons 122 and 123 is proportional to the travel time of the route. The travel time for each route is acquired from the travel time of the respective route information. An arrow 125 displayed superimposed on the destination icon 123 represents the travel time fluctuation range, which is obtained from the standard deviation of the route information. The text 126 represents information on each route in characters. The window 127 is a window for selecting a route for the user. The driver selects a route via the input device 230.

  A processing flow of the display device 240 is shown in FIG. In step S400, it is determined whether all the route information received by the receiving device 220 has been processed. If all have been processed (Yes in S400), the process proceeds to step S440. If not all have been processed, one route to be processed is selected and the process proceeds to step S410.

  In step S410, a text 121 that is the name of the selected route is generated, and a departure point icon 122, a destination icon 123, and a straight line 124 are displayed. The length of the straight line 124 is calculated from the travel time value of the route information. For example, the travel time is displayed as 1 cm per 10 minutes. However, the length of the straight line 124 in each route is adjusted so that the display does not protrude from the screen when the arrow 125 indicating the fluctuation range is displayed over the destination icon 123.

  In step S420, an arrow 125 indicating the fluctuation range is displayed. The length of the arrow 125 is calculated from the standard deviation value of the route information. For example, it is displayed on the screen at 0.5 cm per minute.

  In step S430, text 126 describing the route information is displayed on the screen. The travel time of the route information is displayed as “hour XX minutes”, and the standard deviation as the fluctuation range is displayed as “variation ± XX minutes”.

  In step S440, after all route information is displayed, a window 127 is displayed to prompt the user to select a route.

  According to the embodiment described above, the route distribution device 100 combines a plurality of pieces of traffic information and provides them to the terminal device in consideration of errors and variations in the traffic information. As a result, the traffic information variation information is also reflected, so that it is possible to prevent the traffic information having a large variation from being used preferentially. In addition, by calculating the route using the integrated traffic information, it is possible to prevent the route from changing due to a small change in traffic conditions and to provide a more stable route.

DESCRIPTION OF SYMBOLS 100 Path | route delivery apparatus 110 Reception apparatus 120 Recording apparatus 130 Fusion coefficient production apparatus 140 Fusion coefficient correction apparatus 150 Fusion apparatus 160 Path calculation apparatus 170 Transmission apparatus 200 Terminal apparatus 210 Transmission apparatus 220 Reception apparatus 230 Input apparatus 240 Display apparatus

Claims (3)

In a route distribution device that searches for a route based on an instruction of a departure place and a destination from a terminal device,
A receiving device for receiving information on a departure place and a destination from the terminal device, and a plurality of traffic information from a plurality of information sources;
A fusion coefficient creating device for obtaining an error and variation of the traffic information for each information source, and creating a fusion coefficient that is a weight when fusing the traffic information from the error and variation;
A recording device for storing the created fusion coefficient, map information, and the received traffic information;
A fusion device that fuses current traffic information using the fusion factor;
A route calculation device for calculating a route using the traffic information fused by the fusion device;
A transmission device for transmitting the route to the terminal device ;
Fusion coefficient correction means for correcting the fusion coefficient using an error or variation in the current traffic information received by the receiving device,
The route distribution device characterized in that the fusion device fuses traffic information using the fusion coefficient corrected by the fusion coefficient correction means . The route distribution device according to claim 1 ,
The fusion device stores, in the recording device, error information for each speed band of traffic information relating to an on-road sensor or a roadside sensor as an information source,
The route distribution system, wherein the fusion coefficient correction means corrects the fusion coefficient using error information for each speed band obtained from a road sensor value or a road side sensor value received by the receiving device. The route distribution device according to claim 1 ,
The route distribution system, wherein the recording device records a value preset by a user as a weight of error and variation of traffic information received by the receiving device.

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