JP2009081524A - On-board communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-board communication device capable of speedily acquiring information from another vehicle. <P>SOLUTION: A frame FR transmitted from another vehicle includes information etc., representing "vehicle ID", "position", "message", "signature", "open key", and "open key certificate", and security association (hereinafter SA) includes information representing "vehicle ID", "cipher-signature system", "open key", "frame reception time", and "position". A security association database (hereinafter a SAD) stores SA received from the other vehicle. Then "frame reception time" is extracted from an SA having a row number (i) in the SAD (S230), and the difference Δt_now between the "current time" and "frame reception time" is calculated (S240). Then it is determined whether the Δt_now exceeds a decision time Δt (S270), the SA having the row number (i) is deleted from the SAD (S280) on the condition that the Δt_now exceeds the Δt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an in-vehicle communication device that is mounted on a vehicle and performs communication with a communication device mounted on another vehicle.

  In the broadcast-type two-way communication system, since anyone can send and receive information, there is a possibility that information is falsified by a malicious person. For this reason, a method of excluding the tampered information from the received information by authenticating the communication partner is widely used.

  As a communication partner authentication method in 1: 1 communication, a method of handshaking (established by the IEEE802.11i standard) is known. However, there is a problem that the handshake procedure processing takes time and is not suitable for broadcast-type communication between multiple people.

For this reason, as a communication partner authentication method in 1: N communication, a method of ensuring the authenticity of information contents by performing partner authentication using a public key and using it as signature giving information (for example, is used). , See Patent Document 1). In this method, in order to authenticate a communication partner, each sender has a security association consisting of a combination of a communication protocol, an encryption method, a signature method, a key, and a serial number, and authentication is performed by exchanging this. For this reason, the information receiving side requires a security association database (Security Association DataBase) for storing the security association of each sender.
JP 2005-117254 A

  By the way, as an apparatus mounted on a vehicle, an in-vehicle communication apparatus that performs 1: N wireless communication (hereinafter also referred to as inter-vehicle communication) with another vehicle is known. By receiving information from other vehicles using this in-vehicle communication device, it is possible to know the situation of the vehicle or road in a position that is not visible to the driver, and to detect the danger in advance.

  However, since there are many vehicles on the road, the number of security associations stored in the security association database becomes enormous if communication partner authentication using a public key is adopted for inter-vehicle communication.

  And since the situation of a road or a vehicle changes every moment, it is necessary for an in-vehicle communication device to acquire necessary information quickly from other vehicles. However, in order to determine whether the source of the newly received security association is the same as the source of the security association already stored in the security association database, a huge number of security associations in the security association database It takes a long time to search. For this reason, there is a problem that it takes a long time to verify information acquired from other vehicles by communication, and it becomes impossible to quickly acquire necessary information.

  This invention is made | formed in view of such a problem, and it aims at providing the vehicle-mounted communication apparatus which can acquire information rapidly from another vehicle.

  The vehicle-mounted communication device according to claim 1, wherein the first specifying means continues for a predetermined determination time set in advance, and the security association of another vehicle communication device that has not received the security association. The first deletion unit deletes the security association specified by the first specification unit from the storage unit among the security associations stored in the storage unit.

  In the in-vehicle communication device configured as described above, the security association of the other vehicle communication device that has not received the predetermined determination time is deleted from the storage unit. Note that the non-reception time is used as the determination condition based on the idea that the other vehicle that has not been received for a long time is located far from the own vehicle and is less important for the own vehicle.

  Therefore, according to the vehicle-mounted communication device configured as described above, the number of security associations stored in the storage unit can be reduced. Thereby, it is possible to shorten the time for searching for a desired security association from among the security associations stored in the storage means, and it is possible to quickly acquire information from the other vehicle communication device.

  In addition, said predetermined determination time is set in order to exclude the other vehicle located far from the own vehicle. However, the time required to reach another vehicle located far away varies depending on the traveling speed of the vehicle. For this reason, it is desirable to change the predetermined determination time according to the traveling speed of the vehicle.

  Therefore, in the in-vehicle communication device according to claim 1, as described in claim 2, the own vehicle traveling speed acquisition means indicates the traveling speed of the own vehicle that is a vehicle in which the in-vehicle communication device is mounted. The traveling speed information may be acquired, and the first determination time setting unit may set the predetermined determination time based on the host vehicle traveling speed information acquired by the host vehicle traveling speed acquisition unit.

  According to the vehicle-mounted communication device configured as described above, it is possible to suppress the security association that does not need to be stored depending on the traveling speed of the vehicle from being stored unnecessarily, and appropriately delete the security association.

  In addition, the vehicle usually travels on a highway at a higher speed than a general road. Therefore, in the in-vehicle communication device according to claim 1, as described in claim 3, the road type acquisition unit includes the road type of the road on which the host vehicle that is the vehicle on which the in-vehicle communication device is mounted. The second determination time setting unit may set the predetermined determination time based on the road type information acquired by the road type acquisition unit.

  According to the in-vehicle communication device configured as described above, it is only necessary to determine whether the road type of the road being traveled is a general road or a highway, and therefore the predetermined determination time can be set easily.

  In the in-vehicle communication device according to claim 4, the security association received by communication with the other vehicle communication device includes other vehicle position information indicating the position of the other vehicle, and the own vehicle position acquisition means The own vehicle position information indicating the position of the own vehicle, which is a vehicle on which the in-vehicle communication device is mounted, is acquired, and the distance calculation means includes at least other vehicle position information included in the received security association and the own vehicle position acquisition means. Based on the acquired own vehicle position information, an inter-vehicle distance that is a distance between the own vehicle and another vehicle is calculated. Further, the second specifying means specifies the security association of the other vehicle communication device in which the inter-vehicle distance calculated by the distance calculating means is greater than or equal to a predetermined determination distance set in advance, and the second deleting means is stored in the storage means Of the determined security associations, the security association specified by the second specifying means is deleted from the storage means.

  In the in-vehicle communication device configured as described above, the security association of the other vehicle communication device that is separated from the host vehicle by a predetermined determination distance is deleted from the storage unit. Note that the predetermined determination distance is used as the determination condition based on the idea that the distant other vehicle is less important for the host vehicle.

Therefore, according to the vehicle-mounted communication apparatus comprised in this way, there exists an effect similar to the vehicle-mounted communication apparatus of Claim 1.
In the in-vehicle communication device according to the fourth aspect, as described in the fifth aspect, the inter-vehicle distance may be a linear distance between the host vehicle and the other vehicle.

According to the vehicle-mounted communication device configured as described above, the inter-vehicle distance can be easily calculated based on the position of the host vehicle and the position of the other vehicle.
The information indicating the positions of the host vehicle and the other vehicle may be position information expressed in two dimensions, such as latitude and longitude, but in three dimensions by adding height information to position information such as latitude and longitude. You may use the positional information to represent. By using the three-dimensional position information, for example, the inter-vehicle distance at a three-dimensional intersection can be calculated appropriately.

In the in-vehicle communication device according to the fourth aspect, as described in the sixth aspect, the inter-vehicle distance may be a road length between the own vehicle and another vehicle.
According to the vehicle-mounted communication device configured as described above, it is possible to determine whether or not to delete the security association based on the distance that the vehicle actually moves.

  The predetermined determination distance is set to exclude other vehicles located far from the host vehicle. Therefore, in the in-vehicle communication device according to any one of claims 4 to 6, as described in claim 7, the own vehicle traveling speed acquisition unit obtains own vehicle traveling speed information indicating the traveling speed of the own vehicle. The first determination distance setting unit may acquire the predetermined determination distance based on the host vehicle travel speed information acquired by the host vehicle travel speed acquisition unit.

According to the vehicle-mounted communication device configured as described above, the same effect as the vehicle-mounted communication device according to claim 2 is obtained.
Further, in the in-vehicle communication device according to any one of claims 4 to 7, as described in claim 8, the road type acquisition means indicates the road type indicating the road type of the road on which the host vehicle is traveling. The information may be acquired, and the second determination distance setting unit may set the predetermined determination distance based on the road type information acquired by the road type acquisition unit.

According to the in-vehicle communication device configured as described above, the same effect as the in-vehicle communication device according to claim 3 is obtained.
Further, in the in-vehicle communication device according to claim 9, the third deletion unit sets all the security stored in the storage unit when the accessory power supply of the vehicle on which the in-vehicle communication device is mounted is turned on or off. Delete the association from the storage means.

  According to the in-vehicle communication device configured as described above, since the process for selecting the security association to be deleted is unnecessary, the number of the security associations stored in the storage unit can be easily reduced. In addition, by reducing the number of security associations stored in the storage means, it is possible to shorten the time for searching for a desired security association from among the security associations stored in the storage means, and from other vehicle communication devices. Information can be acquired quickly.

(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a navigation device 1 according to an embodiment to which the present invention is applied.

  The navigation device 1 is mounted on a vehicle and, as shown in FIG. 1, a position detector 21 that detects the current position of the vehicle, a vehicle speed sensor 22 that detects the traveling speed of the vehicle, and an external communication device that communicates with the outside. 23, a data storage device 24 capable of storing map data and various information, an operation switch group 25 for inputting various instructions from the user, and a display for performing various displays such as a map display screen and a TV screen A device 26, a voice output unit 27 for outputting various guidance voices, a microphone 28 for outputting an electrical signal based on voice spoken by the driver, the above-described position detector 21, vehicle speed sensor 22, and external communication Machine 23, data storage device 24, operation switch group 25, and various processes according to inputs from microphone 28, external communication device 23, data storage device 24, display device It has 6 and a control unit 20 which controls the audio output unit 27.

  Among these, the position detector 21 receives a radio wave transmitted from an artificial satellite for GPS (Global Positioning System) via a GPS antenna and detects a position, a direction, and the like of the vehicle, and in addition to the vehicle. Provided with a gyroscope 21b for detecting the magnitude of the rotational motion, a distance sensor 21c for detecting a distance from acceleration in the longitudinal direction of the vehicle, and a geomagnetic sensor 21d for detecting a traveling direction from geomagnetism. . Each of the sensors 21a to 21d has an error having a different property, and is configured to be used while complementing each other. Depending on the accuracy, a part of the sensors described above may be used, or a steering rotation sensor, a wheel sensor of each rolling wheel, or the like may be used.

  The external communication device 23 has a function of performing broadcast-type wireless communication with a communication device (not shown; hereinafter referred to as another vehicle communication device) mounted on another vehicle. Specifically, as shown in FIG. 2 (a), a plurality of vehicles (only three of vehicles 1 to 3 are shown in the figure) are regularly the same for each of the other vehicles. Are simultaneously transmitted (see arrows SF1, SF2, and SF3). Each vehicle receives a frame transmitted from another vehicle.

  Note that a frame FR transmitted from the vehicle (hereinafter referred to as a transmission frame FR or a frame FR) is “vehicle ID”, “position”, “movement direction”, “serial number” as shown in FIG. , “Message”, “signature”, “public key”, and “public key certificate”.

  Among these, “vehicle ID” is information for identifying a vehicle. “Position” is information indicating the latitude and longitude where the vehicle is located. The “movement direction” is information indicating the traveling direction of the vehicle. The “serial number” is a serial number assigned to identify a transmission frame. The “message” is information about the vehicle other than “position” and “movement direction”.

  The data storage device 24 includes various data including so-called map matching data, map data, and mark data for improving the accuracy of position identification, a navigation program executed by the control unit 20 to operate the navigation device 1, and an external This is a device for storing information acquired by the communication device 23 through communication. As a recording medium for these data, a magnetic storage device such as a hard disk is used because of the amount of data. As shown in FIG. 1, the data storage device 24 is provided with a security association database 24a (hereinafter also referred to as SAD 24a) for storing security associations (hereinafter also referred to as SA) received from other vehicles. .

  As shown in FIG. 2C, the SA includes information indicating “vehicle ID”, “encryption / signature method”, “public key”, “frame reception time”, and “position”. The received SAs are stored in the security association database 24a in a preset order (for example, the order in which frames are received).

  The operation switch group 25 is a touch panel installed on the display screen of the display device 26 and mechanical key switches provided around the display device 26. Note that the touch panel and the display device 26 are laminated and integrated, and there are various types of touch panels, such as a pressure-sensitive method, an electromagnetic induction method, a capacitance method, or a combination of these methods. May be.

  The display device 26 is a color display device such as a liquid crystal display, a plasma display, a CRT, or an organic EL, and any of them may be used. On the display screen of the display device 26, a mark indicating the current location identified from the current position of the vehicle detected by the position detector 21 and the map data input from the data storage device 24, a guide route to the destination, a name, Additional data such as landmarks and marks of various facilities can be displayed in an overlapping manner.

  The microphone 28 outputs an electrical signal (voice signal) based on the inputted voice to the control unit 20 when the driver inputs (speaks) voice. The navigation apparatus 1 can be operated by voice commands input via the microphone 28.

  The control unit 20 is composed mainly of a well-known microcomputer comprising a CPU, ROM, RAM, I / O and a bus line connecting these components, and is based on a program stored in the data storage device 24. A map display that calculates the current position of the vehicle as a set of coordinates and traveling directions based on each detection signal from the position detector 21 and displays a map near the current position read from the data storage device 24 on the display device 26. Based on the function and the point data stored in the data storage device 24, the destination facility is selected according to the operation of the operation switch group 25 or the voice input via the microphone 28, and the optimum from the current position to the destination is selected. A route guidance function that performs route calculation (for example, the Dijkstra method) for automatically obtaining a route, and a voice output unit 27 and my Interactive function of controlling the navigation device 1 by entering a voice command from the driver while interaction with the driver through a Rofon 28 comprises (agent function).

  In the navigation apparatus 1 configured as described above, the control unit 20 performs a frame verification process for verifying the received frame FR, an unnecessary SA deletion process for deleting an unnecessary SA, and an all SA deletion for deleting all SAs. Execute the process.

  First, the procedure of the frame verification process executed by the control unit 20 will be described with reference to FIG. FIG. 3 is a flowchart showing the frame verification process. This frame verification process is a process that is repeatedly executed while the control unit 20 is activated (powered on).

  When this frame verification process is executed, the controller 20 first performs wireless communication with a communication device mounted on another vehicle via the external communication device 23 and receives the frame FR in S10. . Thereafter, in S20, the “vehicle ID” is extracted from the received frame FR, and in S30, an SA having the same “vehicle ID” as the extracted “vehicle ID” (hereinafter also referred to as the same ID SA) is designated as SAD 24a. Search from.

  In S40, based on the search result in S30, it is determined whether or not the SA with the same ID exists in the SAD 24a. If there is SA with the same ID (S40: YES), the process proceeds to S90. On the other hand, if there is no SA with the same ID (S40: NO), the "public key" is extracted from the received frame FR at S50, and the "public key certificate" is extracted from the received frame FR at S60. Extract.

  Thereafter, in S70, the “public key” is verified from the “public key certificate”. In S80, based on the verification result in S70, it is determined whether or not the “public key” extracted from the frame FR is a correct public key. If the public key is not correct (S80: NO), the process proceeds to S140. On the other hand, if the public key is correct (S80: YES), the process proceeds to S90.

  In S90, the “signature” is extracted from the received frame FR, and in S100, the contents of the frame FR (“vehicle ID”, “ It is verified whether the “position”, “movement direction”, “serial number”, and “message” are correct (that is, not tampered).

  Thereafter, in S110, it is determined whether or not the content of the frame FR is correct based on the verification result in S100. If the contents of the frame FR are not correct (S110: NO), the process proceeds to S140. On the other hand, if the content of the frame FR is correct (S110: YES), the security association (SA) of the received frame FR is added to the SAD 24a in S120, and the content of the frame FR received in S10 is added in S130. “Message” is extracted from the data, stored in the data storage device 24, and the frame verification process is temporarily terminated.

When the process proceeds to S140, the received frame FR is discarded, and the frame verification process is temporarily ended.
Next, the procedure of unnecessary SA deletion processing executed by the control unit 20 will be described with reference to FIG. FIG. 4 is a flowchart showing unnecessary SA deletion processing. This unnecessary SA deletion process is a process that is executed each time a preset time elapses while the control unit 20 is activated (powered on).

When the unnecessary SA deletion process is executed, the control unit 20 first sets a line number instruction value i indicating the line number of the SAD 24a to “1” in S210.
In S220, it is determined whether or not the line number indicated by the line number instruction value i is the number of the last line of the SAD 24a. Here, if it is the number of the last line (S220: YES), the unnecessary SA deletion process is terminated.

  On the other hand, if it is not the last line number (S220: NO), in S230, the "frame reception time" is extracted from the security association (SA) of the line number indicated by the line number instruction value i, and in S240. A difference Δt_now (hereinafter referred to as a non-reception time Δt_now) between “current time” and “frame reception time” is calculated.

  Thereafter, in S250, the travel speed information indicating the travel speed of the vehicle is acquired from the vehicle speed sensor 22, and in S260, whether or not the security association (SA) is deleted based on the travel speed information acquired in S250. A determination time Δt for determination is set. Specifically, the determination time Δt is set longer as the traveling speed increases. This is based on the idea that the determination time Δt is set to exclude other vehicles located far away from the host vehicle, and that the host vehicle can reach far away as the traveling speed increases.

  As a method for changing the determination time Δt according to the traveling speed, for example, the determination time Δt is changed stepwise according to the traveling speed, or the determination time Δt is changed in proportion to the traveling speed. Is mentioned.

  Thereafter, in S270, it is determined whether or not the non-reception time Δt_now exceeds the determination time Δt. Here, when the non-reception time Δt_now does not exceed the determination time Δt (S270: NO), the process proceeds to S290. On the other hand, if the non-reception time Δt_now exceeds the determination time Δt (S270: YES), the security association (SA) of the line number indicated by the line number instruction value i is deleted from the SAD 24a in S280, and S290. Migrate to

In S290, a value obtained by adding “1” to the line number instruction value i is set as the line number instruction value i. Thereafter, the process proceeds to S220, and the above-described processing is repeated.
Next, the procedure of all SA deletion processing executed by the control unit 20 will be described with reference to FIG. FIG. 5 is a flowchart showing the SA all deletion process. This SA all deletion process is a process executed when an accessory power source (not shown) changes from off to on.

  When this SA all deletion process is executed, the controller 20 deletes all the security associations (SA) stored in the SAD 24a from the SAD 24a in S410, and ends the SA all deletion process.

  In the navigation device 1 configured as described above, the security association (SA) of the other vehicle communication device that has not been received for the determination time Δt is identified (S210, S230, S240, S270, S290) and stored in the SAD 24a. Among the security associations (SA), the identified security association (SA) is deleted from the SAD 24a (S280).

Accordingly, the security association (SA) of the other vehicle communication device that has not received the determination time Δt is deleted from the SAD 24a.
For this reason, the number of security associations (SA) stored in the SAD 24a can be reduced. Thereby, it is possible to shorten the time for searching for a desired security association (SA) from the security associations (SA) stored in the SAD 24a, and it is possible to quickly acquire information from other vehicle communication devices.

Further, travel speed information indicating the travel speed of the vehicle is acquired from the vehicle speed sensor 22 (S250), and a determination time Δt is set based on the acquired travel speed information (S260).
For this reason, it is possible to prevent the security association (SA) that does not need to be stored depending on the traveling speed of the vehicle from being stored in vain and appropriately delete the security association (SA).

Further, when the accessory power supply of the host vehicle is turned on, all the security associations (SA) stored in the SAD 24a are deleted from the SAD 24a (S410).
Therefore, since the process for selecting the security association (SA) to be deleted is not necessary, the number of security associations (SA) stored in the SAD 24a can be easily reduced.

  In the embodiment described above, the navigation device 1 is the in-vehicle communication device in the present invention, the SAD 24a is the storage means in the present invention, the processing in S210, S230, S240, S270, and S290 is the first specifying means in the present invention, and the processing in S280 is The first deletion means in the present invention, the determination time Δt is the predetermined determination time in the present invention, the process of S250 is the own vehicle traveling speed acquisition means in the present invention, the process of S260 is the first determination time setting means in the present invention, the process of S410 Is the third deletion means in the present invention.

(Second Embodiment)
A second embodiment of the present invention will be described below with reference to the drawings. In the second embodiment, only parts different from the first embodiment will be described.

The navigation device 1 in the second embodiment is the same as that in the first embodiment except that the unnecessary SA deletion process is changed.
Here, the unnecessary SA deletion processing procedure of the second embodiment will be described with reference to FIG. FIG. 6 is a flowchart showing unnecessary SA deletion processing of the second embodiment.

  As shown in FIG. 6, the unnecessary SA deletion process of the second embodiment is different from the first embodiment in that the processes of S250 and S260 are omitted and the processes of S255 and S265 are added.

  That is, when the processing of S240 is completed, road type information indicating the type of the road that is currently running is acquired from the map data stored in the data storage device 24 in S255. In S265, based on the road type information acquired in S255, a determination time Δt for determining whether to delete the security association (SA) is set, and the process proceeds to S270. Specifically, the determination time Δt when the road type is a highway is set to be longer than the determination time Δt when the road type is a general road.

  This is because, as in the first embodiment, the determination time Δt is set to exclude other vehicles located far from the host vehicle, and the higher the traveling speed, the shorter the host vehicle can reach far away. Together with the idea, vehicles are usually based on the idea that highways travel faster than regular roads.

  The navigation device 1 configured as described above acquires road type information from map data (S255), and sets a determination time Δt based on the acquired road type information (S265).

For this reason, it is only necessary to determine whether the road type of the running road is a general road or a highway, and therefore the determination time Δt can be set easily.
In the embodiment described above, the process of S255 is the road type acquisition means in the present invention, and the process of S265 is the second determination time setting means in the present invention.

(Third embodiment)
A third embodiment of the present invention will be described below with reference to the drawings. In the third embodiment, only parts different from the first embodiment will be described.

The navigation device 1 according to the third embodiment is the same as that according to the first embodiment except that the unnecessary SA deletion process is changed.
Here, the unnecessary SA deletion processing procedure of the third embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing unnecessary SA deletion processing of the third embodiment.

When the unnecessary SA deletion process is executed, the control unit 20 first sets a line number instruction value i indicating the line number of the SAD 24a to “1” in S510.
In S520, it is determined whether or not the line number indicated by the line number instruction value i is the number of the last line of the SAD 24a. Here, if it is the number of the last line (S520: YES), the unnecessary SA deletion process is terminated.

  On the other hand, if it is not the number of the last line (S520: NO), “position” is extracted from the security association (SA) of the line number indicated by the line number instruction value i in S530, and the position is detected in S540. The current position of the vehicle is calculated based on each detection signal from the device 21.

  In S550, a linear distance Δd_now (hereinafter referred to as an inter-vehicle distance Δd_now) between the “position” extracted in S530 and the “current position” calculated in S540 is calculated.

  Thereafter, in S560, travel speed information indicating the travel speed of the vehicle is acquired from the vehicle speed sensor 22, and in S570, whether or not to delete the security association (SA) based on the travel speed information acquired in S560. Is set to a determination distance Δd. Specifically, the determination distance Δd is set to be longer as the traveling speed is higher.

  As a method for changing the determination distance Δd according to the traveling speed, for example, the determination distance Δd is changed stepwise according to the traveling speed, or the determination distance Δd is changed in proportion to the traveling speed. Is mentioned.

  Further, in S580, it is determined whether or not the inter-vehicle distance Δd_now exceeds the determination distance Δd. If the inter-vehicle distance Δd_now does not exceed the determination distance Δd (S580: NO), the process proceeds to S600. On the other hand, when the inter-vehicle distance Δd_now exceeds the determination distance Δd (S580: YES), in S590, the security association (SA) of the line number indicated by the line number instruction value i is deleted from the SAD 24a, and S600. Migrate to

In S600, a value obtained by adding “1” to the line number instruction value i is set as the line number instruction value i. Thereafter, the process proceeds to S520, and the above-described processing is repeated.
The navigation device 1 configured as described above extracts the “position” from the security association (SA) (S530), calculates the current position of the vehicle based on each detection signal from the position detector 21 (S540), A linear distance Δd_now (inter-vehicle distance Δd_now) between the extracted “position” and the calculated “current position” is calculated (S550). Further, the security association (SA) in which the inter-vehicle distance Δd_now exceeds the determination distance Δd is specified (S510, S580, S600), and the specified security association (SA) is stored in the security association (SA) stored in the SAD 24a. It deletes from SAD24a (S590).

Therefore, the security association (SA) of the other vehicle communication device that is separated from the own vehicle beyond the determination distance Δd is deleted from the SAD 24a.
For this reason, the number of security associations (SA) stored in the SAD 24a can be reduced. Thereby, it is possible to shorten the time for searching for a desired security association (SA) from the security associations stored in the SAD 24a, and to quickly acquire information from other vehicle communication devices.

Further, travel speed information indicating the travel speed of the vehicle is acquired from the vehicle speed sensor 22 (S560), and a determination time Δt is set based on the acquired travel speed information (S570).
For this reason, it is possible to prevent the security association (SA) that does not need to be stored depending on the traveling speed of the vehicle from being stored in vain and appropriately delete the security association (SA).

  In the embodiment described above, the process of S540 is the own vehicle position acquisition means in the present invention, the process of S550 is the distance calculation means in the present invention, the processes of S510, S580, and S600 are the second specifying means in the present invention, the process of S590. Is the second deletion means in the present invention, “position” constituting the security association (SA) is the other vehicle position information in the present invention, the determination distance Δd is the predetermined determination distance in the present invention, and the process of S560 is the vehicle traveling in the present invention The speed acquisition means, S570, is the first determination distance setting means in the present invention.

(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. In the fourth embodiment, only parts different from the third embodiment will be described.

The navigation device 1 according to the fourth embodiment is the same as that according to the third embodiment except that the unnecessary SA deletion process is changed.
Here, the unnecessary SA deletion processing procedure of the fourth embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing unnecessary SA deletion processing of the fourth embodiment.

  As shown in FIG. 8, the unnecessary SA deletion process of the fourth embodiment is different from the third embodiment in that the processes of S560 and S570 are omitted and the processes of S565 and S575 are added.

  That is, when the processing of S550 is completed, road type information indicating the type of road currently running is acquired from the map data stored in the data storage device 24 in S565. In S575, a determination distance Δd for determining whether or not to delete the security association (SA) is set based on the road type information acquired in S565, and the process proceeds to S580. Specifically, the determination distance Δd when the road type is an expressway is set to be longer than the determination distance Δd when the road type is a general road.

  The navigation device 1 configured as described above acquires road type information from the map data (S565), and sets a determination distance Δd based on the acquired road type information (S575).

For this reason, it is only necessary to determine whether the road type of the running road is a general road or a highway, and therefore the determination distance Δd can be set easily.
In the embodiment described above, the process of S565 is the road type acquisition unit in the present invention, and the process of S575 is the second determination distance setting unit in the present invention.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.
For example, in the above embodiment, the linear distance is calculated as the distance between the “position” extracted in S530 and the “current position” calculated in S540, but is stored in the data storage device 24. The road length between “position” and “current position” may be calculated using the map data. By adopting the road length, it is possible to determine whether or not to delete the security association (SA) based on the distance that the host vehicle actually moves.

  In the above embodiment, the distance is calculated using the two-dimensional position information indicating the latitude and longitude. However, the three-dimensional position information may be used by adding the height information. By using the three-dimensional position information, for example, the inter-vehicle distance at a three-dimensional intersection can be calculated appropriately.

  In the above embodiment, the unnecessary SA deletion process is executed every time a preset time elapses. However, when a manual operation is performed, a preset number of frames FR are received. It may be executed every time.

  In the above embodiment, all the security associations (SA) are deleted from the SAD 24a when the accessory power source is changed from off to on. However, the accessory power source is deleted when the accessory power source is changed from on to off. It may be.

1 is a block diagram showing a configuration of a navigation device 1. FIG. It is a figure explaining broadcast type communication, transmission frame FR, and SAD24a. It is a flowchart which shows a frame verification process. It is a flowchart which shows the unnecessary SA deletion process of 1st Embodiment. It is a flowchart which shows a SA all deletion process. It is a flowchart which shows the unnecessary SA deletion process of 2nd Embodiment. It is a flowchart which shows the unnecessary SA deletion process of 3rd Embodiment. It is a flowchart which shows the unnecessary SA deletion process of 4th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Navigation apparatus, 20 ... Control part, 21 ... Position detector, 21a ... GPS receiver, 21b ... Gyroscope, 21c ... Distance sensor, 21d ... Geomagnetic sensor, 22 ... Vehicle speed sensor, 23 ... External communication device, 24 ... Data storage device, 24a ... SAD, 25 ... operation switch group, 26 ... display device, 27 ... voice output unit, 28 ... microphone

Claims (9)

An in-vehicle communication device that transmits and receives a security association by performing broadcast communication with another vehicle communication device that is mounted on a vehicle and is a communication device mounted on another vehicle,
Storage means for storing the security association received by communication with the other vehicle communication device;
First identifying means for identifying a security association of the other vehicle communication device that has not received a security association continuously for a predetermined determination time set in advance;
An in-vehicle communication device comprising: a first deletion unit that deletes, from the storage unit, the security association specified by the first specifying unit among the security associations stored in the storage unit. Own vehicle traveling speed acquisition means for acquiring own vehicle traveling speed information indicating the traveling speed of the own vehicle which is a vehicle equipped with the in-vehicle communication device;
The in-vehicle communication device according to claim 1, further comprising: a first determination time setting unit that sets the predetermined determination time based on own vehicle travel speed information acquired by the own vehicle travel speed acquisition unit. . Road type acquisition means for acquiring road type information indicating the road type of the road on which the host vehicle that is the vehicle on which the in-vehicle communication device is mounted;
The in-vehicle communication device according to claim 1, further comprising: a second determination time setting unit that sets the predetermined determination time based on road type information acquired by the road type acquisition unit. An in-vehicle communication device that transmits and receives a security association by performing broadcast communication with another vehicle communication device that is mounted on a vehicle and is a communication device mounted on another vehicle,
The security association received by communication with the other vehicle communication device includes other vehicle position information indicating the position of the other vehicle,
Storage means for storing the security association received by communication with the other vehicle communication device;
Own vehicle position acquisition means for acquiring own vehicle position information indicating the position of the own vehicle which is a vehicle on which the in-vehicle communication device is mounted;
An inter-vehicle distance that is a distance between the own vehicle and the other vehicle based on at least the other vehicle position information included in the received security association and the own vehicle position information acquired by the own vehicle position acquisition means Distance calculating means for calculating
Second specifying means for specifying a security association of the other vehicle communication device in which the inter-vehicle distance calculated by the distance calculating means is greater than or equal to a predetermined determination distance set in advance;
An in-vehicle communication device comprising: a second deletion unit that deletes, from the storage unit, the security association specified by the second specification unit among the security associations stored in the storage unit. The in-vehicle communication device according to claim 4, wherein the inter-vehicle distance is a linear distance between the host vehicle and the other vehicle. The in-vehicle communication device according to claim 4, wherein the inter-vehicle distance is a road length between the host vehicle and the other vehicle. Own vehicle running speed acquisition means for acquiring own vehicle running speed information indicating the running speed of the own vehicle;
The first determination distance setting means for setting the predetermined determination distance based on the own vehicle travel speed information acquired by the own vehicle travel speed acquisition means. The in-vehicle communication device according to claim 1. Road type acquisition means for acquiring road type information indicating the road type of the road on which the host vehicle is traveling;
7. A second determination distance setting unit configured to set the predetermined determination distance based on road type information acquired by the road type acquisition unit. 8. In-vehicle communication device. An in-vehicle communication device that transmits and receives a security association by performing broadcast communication with another vehicle communication device that is mounted on a vehicle and is a communication device mounted on another vehicle,
Storage means for storing the security association received by communication with the other vehicle communication device;
And a third deleting means for deleting all security associations stored in the storage means from the storage means when the accessory power supply of the vehicle equipped with the in-vehicle communication device is turned on or off. In-vehicle communication device.

Images