JP3953062B2 - Interpolation method of traffic information in navigation system - Google Patents

Description

The present invention relates to a traffic information interpolation method in a navigation system.

Conventionally, for example, as in the navigation method disclosed in Patent Document 1 below, the received traffic information is accumulated as accumulated data together with the date and day of the week, and the shortest route and required time are obtained using this accumulated data. There is something.
JP 2002-148067 A

  However, in the above navigation method, the received traffic information is not normally provided for all links, and data may not exist normally, such as missing data. Accordingly, when such stored data with low reliability is used, there is a problem that the reliability of route search is also lowered.

In order to cope with the above problem, the present invention provides a traffic in which incomplete data in the traffic information is interpolated into valid data when there is incomplete data in the traffic information data received by the navigation system. and an object thereof is to provide Hisage an interpolation method of information data.

In order to achieve the above object, the present invention accumulates traffic information for each link as a file together with time information, and interpolates the accumulated traffic information, wherein the traffic information for each link in the file is If the traffic information does not exist as a result of the check, it is determined whether the time when the traffic information does not exist is the first time in the file, and the traffic information If the time at which the traffic information does not exist is the first time in the file, the traffic information is set to the same value as the traffic information at the nearest time after the time, and the time at which the traffic information does not exist is the first time. If it is not a time, and the time when the traffic information does not exist is the last time in the file, the traffic information Is the same value as the value of the traffic information at the closest time before the time, and the time when the traffic information does not exist is not the last time, the traffic information one hour before or after the time is It is determined whether or not it exists, and when the traffic information before or after the time is present, the traffic information is interpolated by a value obtained by statistically processing the traffic information before and after the time. The present invention provides a traffic information interpolation method in a navigation system.

According to the interpolation method of the traffic information according to the present invention described above, by regarding the stored link travel time between the astringency Todokodo as files, as between the astringency Todokodo when link travel each time information is present Interpolate links for which no data exists. Therefore, it is always between the time link travel and astringency Todokodo at all times of the respective links exist, it is possible to more accurate statistical processing.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, symbol N indicates a navigation system mounted on an automobile, symbol C indicates a dedicated information communication system provided in the dedicated information center, and symbol T indicates road traffic information communication provided in the road traffic information center. A system (hereinafter also referred to as VICS) is shown. “VICS” is a registered trademark.

  The navigation system N includes a current position detection device 10, which is a GPS reception device that receives radio waves transmitted from an artificial satellite of a satellite navigation system (also referred to as GPS). Thus, the current position of the car is detected together with the current time.

  Further, the navigation system N includes an input device 20, and this input device 20 is a portable remote controller, and by operation thereof, necessary information is received by a receiving unit (illustrated) of a microcomputer 30 (described later). Do not send). Instead of the remote controller, a touch panel attached to a liquid crystal panel (described later) of the output device 60 from the display surface side may be used as the input device 20.

  The navigation system N includes a microcomputer 30, a storage device 40, a wireless communication device 50, and an output device 60. The microcomputer 30 is configured by connecting a CPU, a RAM, a ROM, and the like in addition to the above-described receiving unit via a bus line.

  The microcomputer 30 displays the map of the vehicle based on the detection output of the current position detection device 10, the operation output of the input device 20, the output of the storage device 40, the output of the wireless communication device 50 and the output of the dedicated information communication system C. Various processes such as guidance route search and route guidance are performed.

  The storage device 40 is a hard disk, and a series of map data and traffic information data is stored in the storage device 40 as a database so that it can be read out by the microcomputer 30. The wireless communication device 50 receives road traffic information from the dedicated information communication system C and outputs it to the microcomputer 30.

  The dedicated information communication system C includes a server 70, a wireless communication device 80, and a storage device 90. The wireless communication device 80 performs wireless communication between the wireless communication device 50 and VICST. The server 70 executes the server program according to the flowcharts shown in FIGS. The server 70 performs transmission / reception processing between the wireless communication device 50 and VICST via the wireless communication device 80 during execution of the server program. The server program is written in advance in the ROM of the server 70 so as to be readable by the server 70.

  In the storage device 90, traffic information data such as link travel time TT, vehicle speed, congestion degree D, traffic stoppage or traffic restriction transmitted from VICST is stored in the database of the storage device 90 as VICS data. Here, the degree of traffic congestion D refers to the degree of traffic congestion. The traffic congestion degree D includes, for example, “congested”, “congested”, “no traffic jam” data and “unknown” from the higher level of traffic jam. There are four levels of data. Note that the degree of congestion D is not limited to four stages, and may generally be a plurality of stages.

  Further, the storage device 90 stores a VICS link length L as map data. Note that the VICS link length L is the actual length of the target link.

  The output device 60 is a display device, and displays data necessary for the vehicle as information under the control of the microcomputer 30. The output device 60 is disposed on an instrument panel provided on the front wall of the vehicle interior of the vehicle, such as a liquid crystal panel.

  In the present embodiment configured as described above, the dedicated information communication system C interpolates the VICS data received from VICST as follows.

  In step 100, the target data is read from the storage device 90. Accordingly, the link travel time TT, the traffic congestion degree D, the time corresponding to them, and the VICS link length L are read from the database of the storage device 90.

Next, in step 200, the VICS data format is interpolated. By this process, it is determined whether the link travel time TT and the traffic congestion degree D exist for each link at each time, and if it is determined that the link travel time TT or the traffic congestion degree D does not exist, Data indicating that the link travel time TT or the congestion degree D does not exist (hereinafter referred to as empty data) is created.

  Thereafter, in step 300, data interpolation assist processing for VICS data is performed. Accordingly, “no data” is input to the empty data of the link travel time TT created in step 200, and “unknown” is input to the empty data of the congestion degree D.

As described above, by inputting “no data” or “unknown” data in the link for which it is determined that the link travel time TT or the congestion degree D does not exist, data is always obtained at all times and links of the VICS data. Will exist. Further, as will be described below, all VICS data can be interpolated based on “no data” or “unknown” data .

  Next, the processing of the link travel time interpolation processing routine 400 (see FIG. 3) is performed at each time in each link as follows. First, in step 410 of FIG. 3, it is determined whether or not the link travel time TT at the time is “unknown” or “no data”. For example, if the link travel time TT at the time is not “unknown” or “no data”, NO is determined in step 410 and the process proceeds to step 450.

  If the link travel time TT at the time is “unknown” or “no data” at step 410 described above, it is determined YES, and at step 420, the data at the head time of the link travel time TT at the time is determined. It is determined whether or not. If the link travel time TT at the time is data at the head time, YES is determined in step 420. Next, in step 421, an interpolation process is performed. Accordingly, the link travel time TT at the head time is interpolated to be the same value as the link travel time TT at the time closest to the time instead of “unknown” or “no data” after the time. Then, the process proceeds to step 450.

  In step 420 described above, if the link travel time TT at the time is not data at the first time, NO is determined, and in step 430, is the link travel time TT at the time being data at the last time? It is determined whether or not. If the link travel time TT at the time is the data at the last time, YES is determined in step 430. Next, in step 431, an interpolation process is performed. Accordingly, the link travel time TT at the last time is interpolated to be the same value as the link travel time TT at the time closest to the time, not “unknown” or “no data” before the time. Then, the process proceeds to step 450.

  In step 430 described above, if the link travel time TT at the time is not the data at the last time, NO is determined, and in step 440, the link travel time TT one hour before and one time after the time is determined. It is determined whether it is “unknown” or “no data”.

  If the link travel time TT one hour before and after the time is not “unknown” or “no data”, it is determined as NO in step 440. Next, in step 441, linear interpolation processing of the link travel time TT is performed. Accordingly, the link travel time TT at that time is interpolated so as to have the same value as the linear interpolation between the link travel time TT one hour before that time and the link travel time TT after one time. move on.

  In step 440 described above, if the link travel time TT one hour before or after the time is “unknown” or “no data”, it is determined YES, and in step 442, the link travel time TT is set. Interpolation processing is performed. Accordingly, if the link travel time TT one hour before the time is “unknown” or “no data”, the link travel time TT is not “unknown” or “no data” before the time, Interpolation is performed so as to have the same value as the linear interpolation between the link travel time TT at the time closest to the time and the link travel time TT one hour after the time.

  Further, if the link travel time TT one hour after the time is “unknown” or “no data”, the link travel time TT is not “unknown” or “no data” after the time, but the time Is interpolated so as to have the same value as the linear interpolation between the link travel time TT at the closest time to the link travel time TT one hour before that time.

  Next, in step 450, it is determined whether or not the examination of the interpolation processing of the link travel time TT for each time in each link is completed. If the study of the interpolation processing for the link travel time TT at each time for each link has not been completed, NO is determined in step 450 and the processing of the link travel time interpolation processing routine 400 is performed again. Thereafter, the processing of the link travel time interpolation processing routine 400 is repeated until the determination in step 450 becomes YES.

  As described above, when there is data of “unknown” or “no data” in the data of the link travel time TT, the link travel time TT before the time and the link travel time TT after the time are as described above. By performing a simple interpolation process, it is possible to interpolate an effective link travel time at the time and improve the data quality of the VICS data after the above process.

  In step 450 described above, the examination of the interpolation processing of the link travel time TT for each time in each link is completed, and if it is determined as YES, the processing of the congestion degree interpolation processing routine 500 (see FIG. 4) is performed in each link. It is made as follows at each time. First, in step 510 of FIG. 4, it is determined whether or not the degree of congestion D at that time is “unknown”. For example, if the traffic congestion degree D is not “unknown”, NO is determined in step 510 and the process proceeds to step 560.

  If the congestion degree D is “unknown” in step 510 described above, it is determined YES, and in step 520, whether the link travel time TT and the VICS link length L corresponding to the time of the target link exist. It is determined whether or not. If the link travel time TT and the VICS link length L corresponding to the time of the target link exist, YES is determined in step 520. Next, in step 521, a vehicle speed calculation process for the vehicle speed V is performed. Along with this, the vehicle speed V is calculated by the equation (1).

V = L / TT (Equation 1)
Next, in step 522, a congestion level setting process is performed. Accordingly, the degree of traffic congestion D is based on the map-like data shown in Table 1 below, using road types (hereinafter referred to as road types) and vehicle speeds V of general roads, urban highways, and intercity highways as follows Is set.

この表１のマップ状データでは、車速Ｖが道路種別及び渋滞度Ｄとの間の関係において特定されている。なお、表１のデータは、マイクロコンピュータ３０のＲＯＭに予め記憶されている。

In the map-like data in Table 1, the vehicle speed V is specified in the relationship between the road type and the congestion degree D. The data in Table 1 is stored in advance in the ROM of the microcomputer 30.

  Thus, for example, when the target road type is a general road and the vehicle speed V = 15 km / h, the congestion degree D is set to “congested” based on the data in Table 1.

  Further, if the link travel time TT or the VICS link length L corresponding to the relevant time of the target link does not exist in step 520 described above, it is determined as NO, and in step 530, the congestion degree D of the relevant time is the first It is determined whether or not the data is in the data. If the congestion degree D at the time is the data at the head time, it is determined as YES at step 530. Next, in step 531, an interpolation process is performed. Accordingly, the congestion degree D at the head time is interpolated to be the same as the congestion degree D at the time closest to the time, not “unknown” after the time, and the process proceeds to step 560.

  Further, in step 530 described above, if the congestion degree D at the time is not the data at the head time, it is determined NO, and in step 540, whether or not the congestion degree D at the time is the data at the last time. Is determined. If the traffic congestion degree D at the time is the data at the last time, it is determined as YES at step 540. Next, in step 541, an interpolation process is performed. Accordingly, the congestion degree D at the last time is interpolated to be the same as the congestion degree D at the time closest to the time, not “unknown” before the time, and the process proceeds to step 560.

  Further, in step 540 described above, if the congestion degree D at the time is not the data at the last time, it is determined NO, and in step 550, the congestion degree D one hour before and one hour after the time is “unknown” Is determined.

  If the traffic congestion degree D one hour before and after one hour is not “unknown”, NO is determined in step 550. Next, in step 551, a linear interpolation process for the degree of congestion D is performed. Accordingly, the congestion degree D at that time takes an average of the congestion degree one hour before that time and the congestion degree one hour after that time.

  At this time, for example, when the average is between “congestion” and “congestion”, the congestion degree D is set to the lower congestion degree, that is, “congestion”. When the average is between “congested” and “no traffic jam”, the traffic congestion degree D is set to “no traffic jam”.

  In step 550 described above, if the congestion degree D one hour before or after that time is “unknown”, it is determined YES, and in step 552, the congestion degree D is interpolated. Accordingly, if the congestion level one hour before the time is “unknown”, the congestion level D is not “unknown” before the time but the congestion level D at the time closest to the time and the traffic level D. The average is taken with the degree of congestion D one hour after the time. Further, if the degree of traffic congestion one hour after the time is “unknown”, the traffic congestion level D is not “unknown” after the time, but the traffic congestion level D closest to the time and the time of the time Take the average of the congestion level one hour ago. At that time, when the average is between “congestion” and “congestion” or “congestion” and “no congestion”, the congestion degree D is set to the lower congestion degree.

  Next, in step 560, it is determined whether or not the examination of the interpolation processing of the congestion degree D at each time in each link is finished. If the examination of the interpolation process of the congestion degree D at each time in each link has not been completed, NO is determined in step 560, and the process of the congestion degree interpolation process routine 500 is performed again. Thereafter, the processing of the congestion degree interpolation processing routine 500 is repeated until the determination in step 560 becomes YES.

  As described above, in the case where there is “unknown” data in the data of the traffic congestion degree D, by performing the above-described interpolation processing from the traffic congestion degree D before and after the time concerned, The effective congestion degree D at the time can be interpolated, and the data quality of the processed VICS data can be improved. Even if the congestion degree D set based on the vehicle speed V calculated from the link travel time TT and the VICS link length L is interpolated, the data quality of the VICS data can be improved as described above.

  In step 560 described above, the examination of the interpolation processing of the congestion degree D at each time in each link is completed, and if it is determined to be YES, the processing of the unchanged VICS data deletion processing routine 600 (see FIG. 5) is performed. The process is performed as follows for each predetermined period. First, in step 610 of FIG. 5, data extraction processing is performed for each predetermined period in each link. Accordingly, the link travel time TT, the congestion degree D, and the VICS link length L within a predetermined period in each link are extracted from the storage device 90. The predetermined period may be, for example, one day or one month.

  Next, in step 620, it is determined whether or not the link travel time TT within a predetermined period in the target link is unchanged. For example, if all the link travel times TT within a predetermined period in the target link are the same value, it is determined that there is no change and YES is determined in step 620.

  Next, in step 630, it is determined whether or not the degree of congestion D within a predetermined period in the target link is unchanged. For example, if all the congestion levels D within a predetermined period in the target link are the same, it is determined that there is no change and YES is determined in step 630.

  Next, in step 630a, it is determined whether or not the degree of congestion D within the predetermined period in the target link is “no congestion”. For example, if all the congestion degrees D within a predetermined period in the target link are “congestion”, it is determined as NO in Step 630a.

  Thereafter, in step 631, the link travel time and the congestion degree are deleted. Along with this, all the data of the link travel time TT and the congestion degree D within the predetermined period in the target link are deleted, and the process proceeds to Step 660. Further, in step 630 a described above, if all the congestion degrees D within a predetermined period in the target link are “no congestion”, the determination is YES, and the process proceeds to step 632. If it is determined as NO in step 630 described above, the process proceeds to step 632.

  In step 632, all link travel times TT within a predetermined period of the target link are set to “no data”. Thereafter, the process proceeds to step 640. In step 620 described above, if all the link travel times TT within the predetermined period in the target link are not the same value, it is determined as NO and the process proceeds to step 640.

  In step 640, it is determined whether or not the degree of congestion D in the target link within a predetermined period is in an abnormal state. Here, the abnormal state of the congestion degree D indicates a state in which all the congestion degrees D within a predetermined period in the target link are “congested”, “congested”, or “unknown”. For example, if all the congestion degrees D within a predetermined period in the target link are “congestion”, it is regarded as an abnormal state, YES is determined in step 640, and the process proceeds to step 650. Further, when the congestion degree D within the predetermined period in the target link is not any of “congestion”, “congestion”, and “unknown”, the congestion degree D is regarded as not in an abnormal state, and it is determined as NO in step 640. Go to step 660.

  Next, in step 650, it is determined whether or not the link travel time TT within a predetermined period in the target link is unchanged. For example, if all the link travel times TT within a predetermined period in the target link are the same value, the link travel time TT is determined not to change and YES is determined in step 650.

  Thereafter, in step 651, the link travel time and the congestion degree are deleted. Along with this, all the data of the link travel time TT and the congestion degree D within the predetermined period in the target link are deleted, and the process proceeds to Step 660.

  If it is determined NO in step 650 described above, a vehicle speed calculation process for the vehicle speed V is performed in step 652. Accordingly, the vehicle speed V is calculated from the link travel time TT and the VICS link length L based on the above equation (1).

  Thereafter, in step 653, a congestion level setting process is performed. Accordingly, the congestion degree D is set using the road type and the vehicle speed V based on the map data shown in Table 1 above.

  Next, in step 660, it is determined whether or not the review of the VICS data deletion process for each predetermined period in each link has been completed. If the examination of the VICS data deletion process for each predetermined period in each link has not been completed, NO is determined in Step 660 and the process of the unchanged VICS data deletion process routine 600 is performed again. Thereafter, the process of the unchanged VICS data deletion process routine 600 is repeated until the determination in step 660 becomes YES.

  As described above, there is no change in the VICS data in the target period in the target link, and there is always only reliable and valid VICS data by deleting or correcting the VICS data that is clearly regarded as abnormal data. It becomes. Therefore, the data quality of the VICS data after the above processing can be improved.

  In step 660 described above, when the VICS data no-change VICS data deletion process for each predetermined period in each link is completed and it is determined YES, the process of the noise VICS data deletion process routine 700 (see FIG. 6) is performed. The process is performed as follows for each predetermined period. First, in step 710 of FIG. 6, data extraction processing for each predetermined period in each link is performed. Accordingly, the link travel time TT and the congestion degree D within a predetermined period for each link are extracted from the storage device 90. The predetermined period may be, for example, one day or several hours.

  Next, in step 720, FFT calculation processing is performed for the link travel time TT within a predetermined period in the target link. Accordingly, the frequency analysis of the link travel time TT within a predetermined period in the target link is performed, and the frequency regions of the signal part and the noise part are calculated.

  Thereafter, in step 730, it is determined whether or not there is a significant difference between the calculated frequency region of the signal portion and the frequency region of the noise portion. For example, if the S / N ratio between the signal part and the noise part in the frequency region 300 μHz is not 20 dB or less, it is determined that there is a significant difference, YES is determined in step 730, and the process proceeds to step 750.

  In step 730 described above, if there is no significant difference between the frequency region of the signal portion and the frequency region of the noise portion, NO is determined in step 730, and the target VICS data deletion process is performed in step 740. Along with this, all the data of the link travel time TT within the predetermined period in the target link is deleted.

  Next, in step 750, it is determined whether or not the review of the noise VICS data deletion process at the link travel time TT within a predetermined period of each link is completed. If the review of the noise link deletion process at the link travel time TT within the predetermined period of each link has not been completed, it is determined as NO in Step 750, and the process of the noise VICS data deletion process routine 700 is performed again. Thereafter, the processing of the noise VICS data deletion processing routine 700 is repeated until the determination in step 750 becomes YES.

  As described above, the S / N ratio of the link travel time TT within a predetermined period in the target link is obtained, and when this S / N ratio is considered to be low and the significant difference is considered low, the predetermined SNR in the target link is determined. By deleting the link travel time TT within the period, the reliability of the data can be improved. Therefore, the data quality of the VICS data after the above processing can be improved.

  When the VICS data correction process is completed in the dedicated information communication system C as described above, a VICS data transmission process is performed in Step 800. Accordingly, the server 70 transmits the corrected VICS data to the microcomputer 30 via the wireless communication device 80 and the wireless communication device 50. The received VICS data is accumulated in the database of the storage device 40.

  The microcomputer 30 searches for route guidance based on the display request from the input device 20. At the time of the route search process, the microcomputer 30 can perform a route search taking into account highly accurate traffic jam prediction based on the highly reliable VICS data stored in the database of the storage device 40.

  As described above, since accurate VICS data can be used for prediction in the navigation processing, the navigation system N can provide accurate route guidance.

In carrying out the present invention, the following various modifications are possible without being limited to the above embodiment.
(1) In the VICS data format interpolation process in step 200 described above, not only the VICS data in all periods is processed, but also the process is limited to a specified period in units of several hours for one month, one day, for example. May be done.
(2) In the above-described linear interpolation processing of the congestion degree D in step 551, not only interpolation from both congestion levels before and after the time but also transmitted from VICST and stored in the storage device 90 together with the congestion degree D and the like. The degree of traffic jam may be interpolated based on a traffic jam section such as a traffic jam length. For example, when the traffic congestion section at the time is the same traffic congestion section one hour before or after the time, the traffic congestion degree at the time may be the same value as the traffic congestion degree at the time of the same traffic congestion section. Good.
(3) The dedicated communication information system C described above receives the VICS data from the road traffic information center, performs the processing in steps 100 to 700 described above, and transmits it to the navigation system N. The navigation system N directly Alternatively, the VICS data from the road traffic information center may be received and the processing in steps 100 to 700 described above may be performed.
(4) In step 200 described above, after empty data is created for a link that does not have link travel time TT or congestion degree D data so that link travel time TT and congestion degree D data exist at each time. In step 300, “no data” is input to the empty data of the link travel time TT, and “unknown” is not input to the empty data of the congestion degree D. For example, the empty data is input. In addition, “no data” may be directly input to a link having no link travel time TT, and “unknown” may be directly input to a link having no congestion degree D data.
(5) In this embodiment, linear interpolation has been described as the interpolation processing. However, interpolation processing may be performed using an average, a median value, or the like.

It is a block diagram which shows the traffic information data interpolation apparatus which concerns on this invention. It is a flowchart showing the server program performed with the server of the private information communication system of FIG. It is a detailed flowchart of the link travel time interpolation process routine of FIG. 3 is a detailed flowchart of a congestion degree interpolation processing routine of FIG. FIG. 3 is a detailed flowchart of an unchanged VICS data deletion processing routine of FIG. 2. FIG. 3 is a detailed flowchart of a noise VICS data deletion processing routine of FIG. 2.

Explanation of symbols

C ... Dedicated information communication system, N ... Navigation system, T ... VICS, TT ... Link travel time, D ... Congestion degree, 30 ... Microcomputer, 70 ... Server, 90 ... Storage device.

Claims (4)

In a method for accumulating traffic information for each link as a file together with time information, and interpolating the accumulated traffic information,
It is checked whether or not the traffic information for each link exists at each time in the file. If the traffic information does not exist as a result of the check, the time when the traffic information does not exist is the first in the file. Determine if it ’s time,
If the time when the traffic information does not exist is the first time in the file, the traffic information is the same value as the value of the traffic information at the nearest time after the time,
If the time when the traffic information does not exist is not the first time, and the time when the traffic information does not exist is the last time in the file, the traffic information at the nearest time before the time is the traffic. The same value as the information value,
If the time when the traffic information does not exist is not the last time,
It is determined whether or not the traffic information before or after one time exists, and when the traffic information before or after the one time exists, the traffic information before and after the time A method for interpolating traffic information in a navigation system, wherein the traffic information is interpolated from a value obtained by statistically processing the traffic information. When the traffic information of the one hour before the traffic information does not normally exist, the traffic information is interpolated as the traffic information of the one hour before using the previous traffic information closest to the traffic information. The method for interpolating traffic information in the navigation system according to claim 1. When the traffic information after the one hour of the traffic information does not normally exist, the traffic information is interpolated as the traffic information after the one hour using the traffic information that is closest to the traffic information. A method for interpolating traffic information in the navigation system according to claim 1 or 2. In a method of accumulating the degree of congestion for each link by file with time information and interpolating the accumulated degree of congestion,
  In the file, it is checked whether or not the congestion degree for each link exists at each time, and if the congestion degree does not exist as a result of the check, the congestion degree before and after the time when the congestion degree does not exist A traffic information interpolation method in a navigation system, characterized in that, when the traffic congestion level is averaged and the average is between two traffic congestion levels, the lower one of the two traffic congestion levels is set as the traffic congestion level which is lower.

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