JP2016111583A - Communication device and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the communication efficiency of position information due to inter-vehicle multi-hop communication by increasing the number of pieces of position information of a mobile object which can be transmitted in one communication frame.SOLUTION: An information processing part 150 acquires position information of an own device transmitted from a position detection part 120, and other device transmission position information including position information (transmission device position information) of other communication device transmitted from the other communication device through a radio transmission/reception part 110 among communication devices (100, 200, ...) for performing short-range radio communication of a prescribed standard. Subsequently, the information processing part 150 generates compound position information including the position information of the own device and relative position information of the other communication device to the own device on the basis of the acquired own device position information and other device transmission position information. Then, the information processing part 150 transmits the generated compound position information to the outside by using the radio transmission/reception part 110.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a communication device, a communication method, a communication program, and a recording medium on which the communication program is recorded.

  Conventionally, communication using wireless LAN communication is performed between an access point (AP) device and a terminal device, or between a terminal device and a terminal device. In such wireless LAN communication, in many cases, location information is exchanged between wireless LAN communication devices.

  When exchanging such location information, a technique is known in which a service set identifier (SSID) whose information content can be freely defined includes information reflecting the positioning result of the location of the wireless LAN communication device. This SSID can contain information of up to 32 characters. Here, as each character, one of 94 types of codes including codes corresponding to “0” to “9” can be selected. Of the 94 types of codes, about 2 types are preferably used for delimiters and the like, so about 92 types are generally used freely.

  By the way, the position of the wireless LAN communication device can be obtained in the form of the decimal information and the decimal information up to the eighth decimal place when positioning using a GPS (Global Positioning System) satellite is performed. It is common. In order to express the positioning result corresponding to the decimal display, when codes corresponding to “0” to “9” are adopted, at least 23 of 32 characters in the SSID including the distinction between north latitude / south latitude and east longitude / west longitude. Will use characters. In this case, among the 23 characters, 11 characters are used for latitude information, and 12 characters are used for longitude information.

  Now, since SSID can freely define the information content, it is preferable that the number of characters used for one purpose is small. Thus, a technique has been proposed that can reduce the number of characters used for transmitting position information using SSID (see Patent Document 1: hereinafter referred to as “conventional example”).

  In the technique of this conventional example, at the time of broadcast transmission of position information, each of latitude information and longitude information is converted into a hexadecimal display and inserted into the SSID. The wireless LAN communication device that has received the position information inserted in the SSID decodes the latitude information and the longitude information that are displayed in hexadecimal.

JP 2009-089395 A

  In the technique of the conventional example described above, since the latitude information and the longitude information are displayed in hexadecimal notation, the number of characters used for position information can be reduced as compared with the case where decimal information is displayed. As a result, according to the technique of the conventional example, the amount of communication used for transmission / reception of position information is made more efficient than in the case of decimal display.

  Further, as described above, since about 92 types of codes can be used in the SSID, N (≦ 92) decimal display using more than 60 N types of codes for displaying latitude information and longitude information is used. Then, the number of characters used for position information can be further reduced. For example, if the display is in 92 notation using 92 types of codes, latitude information and longitude information can be expressed with an accuracy of about 1 m by using 12 digits.

  By the way, the technology of the above-described conventional example is a technology that assumes that an access point (AP) device transmits only its own location information. On the other hand, if wireless LAN communication (so-called inter-vehicle communication) is performed between terminal devices mounted on a mobile body such as a vehicle, and the mobile body position that each grasps is notified by a multi-hop method, Each terminal device can grasp the position of the terminal device existing in the vicinity, that is, the position of the mobile object existing in the vicinity. Thus, if the position of the moving body existing in the vicinity is grasped and the grasped information is presented to the user, the user can recognize the position of the moving body existing in the vicinity.

  However, if the position information of a plurality of mobile units is accommodated in the SSID using the technology of the conventional example and communication by the multi-hop method (hereinafter also referred to as “multi-hop communication”) is performed, one communication The number of pieces of position information with an accuracy of about 1 m of a mobile that can be transmitted in a frame is limited to “2” or less. This is because the SSID is information of 32 characters, and 12 characters are used for the positional information with an accuracy of about 1 m of one moving body even if it is displayed in 92 notation.

  For this reason, a technique for increasing the number of mobile location information that can be transmitted in one communication frame and improving the communication efficiency of location information by multi-hop communication between vehicles is desired. Meeting this requirement is one of the problems to be solved by the present invention.

  The invention according to claim 1 is a transmission / reception unit that transmits / receives information by short-range wireless communication; and another device transmission position that includes position information of the other communication device transmitted from the other communication device using the transmission / reception unit. An acquisition unit that acquires information and position information of the own device; based on the position information of the own device and other device transmission position information acquired by the acquisition unit, the position information of the own device and the other for the own device An information generation unit that generates composite position information including relative position information of the communication device, and transmits the generated composite position information to the outside using the transmission / reception unit. is there.

  The invention according to claim 7 is a transmission / reception unit that transmits / receives information by short-range wireless communication; and another device transmission position that includes position information of the other communication device transmitted from the other communication device using the transmission / reception unit A communication method used in a communication device comprising: information and an acquisition unit that acquires position information of the own device, based on the position information of the own device and the other device transmission position information acquired by the acquisition unit A generating step of generating composite position information including position information of the own device and relative position information of the other communication device with respect to the own device; and outputting the generated composite position information to the outside using the transmission / reception unit A transmission method comprising: a transmission step for transmitting.

  The invention described in claim 8 is a communication program that causes a computer included in the communication apparatus to execute the communication method described in claim 7.

  The invention according to claim 9 is a recording medium in which the communication program according to claim 8 is recorded so as to be readable by a computer included in the communication apparatus.

It is a figure for demonstrating the structure of the communication apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the information memorize | stored in the memory | storage part of FIG. It is a figure for demonstrating the content of vehicle position SSID. It is a figure for demonstrating the conversion to relative position information, and the conversion from relative position information. It is a flowchart for demonstrating the transmission process of vehicle position SSID. It is a flowchart for demonstrating the receiving process of vehicle position SSID. It is a flowchart for demonstrating the registration process to the memory | storage part of FIG. It is a figure for demonstrating the example of a display of vehicle position information.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[Constitution]
FIG. 1 shows a configuration of a communication apparatus 100 according to an embodiment. As shown in FIG. 1, the communication device 100 is disposed in the vehicle CR ₀ .

The communication device 100 can wirelessly communicate with a communication device 200 _j disposed in another vehicle CR _j (j = 1,..., N) in accordance with a WiFi (Wireless Fidelity) standard. Here, in Japan, wireless communication according to the WiFi standard cannot generally perform wireless communication between devices over a distance exceeding 350 [m]. Further, according to the communication apparatus 100, other vehicle CR _1, ... position of CR _N (hereinafter, referred to as "vehicle position") when particular, the identification accuracy can be said sufficient degree 1 [m].

In the following description, each communication device 200 _j is configured in the same manner as the communication device 100. The 350 [m] described above is also referred to as “longest reachable distance D _MAX ”.

Note that 350 [m] described above is an example in the case of short-range wireless communication according to the WiFi standard in Japan, and the maximum reachable distance _DMAX is determined based on the short-range wireless standard adopted by each country. .

By the way, if the latitude is different by 1 × 10 ⁻⁶ degrees in decimal display, a distance of 0.5 [m] or less will be separated if the longitude is the same, no matter how many times the longitude is. In addition, when the longitude is different by 1 × 10 ⁻⁶ degrees in decimal display, a distance of 0.5 [m] or less is separated even when the latitude is 0 degrees and the longest.

  For this reason, if latitude information and longitude information can be detected with decimal display with an accuracy of the sixth decimal place, position detection can be performed with a detection accuracy within 1 [m]. The number of GPS satellites for realizing such detection accuracy of 1 [m] or less by GPS (Global Positioning System) positioning is N.

<Configuration of Communication Device 100>
Next, the configuration of the communication device 100 will be described.

  As illustrated in FIG. 1, the communication device 100 includes a wireless transmission / reception unit 110, a position detection unit 120, and a storage unit 130. In addition, the communication device 100 includes a display unit 140 and an information processing unit 150.

The wireless transmission / reception unit 110 performs wireless communication according to the WiFi standard with an external device such as the communication device 200 _j (j = 1,..., N). When receiving data from an external device, the wireless transmission / reception unit 110 sends the received data to the information processing unit 150. Such received data includes a vehicle position SSID including the position information of the external apparatus broadcast by the external apparatus as transmission apparatus position information.

  In addition, the wireless transmission / reception unit 110 transmits data transmitted from the information processing unit 150 to an external device. Such transmission data includes a vehicle position SSID including the position information of the communication apparatus 100 as the transmission apparatus position information.

  The position detection unit 120 has a GPS positioning function. The own device position (latitude, longitude) and accuracy, which are positioning results by the position detection unit 120, are sent to the information processing unit 150. Here, “latitude” in the positioning result is composed of identification information of north latitude / south latitude (N / S) and numerical values up to the sixth decimal place in decimal display. Further, “longitude” in the positioning result is composed of identification information of east longitude / west longitude and numerical values up to the sixth decimal place in decimal display. In the present embodiment, the “accuracy” in the positioning result is “high” when the number of GPS satellites that can be used for positioning is N or more, and “low” when the number is less than N. Become.

  The storage unit 130 stores various information used in the communication device 100. The information processing unit 150 can access the storage unit 130.

  Information stored in the storage unit 130 will be described later.

  The display unit 140 includes a display device such as a liquid crystal panel. The display unit 140 displays an image corresponding to the display data sent from the information processing unit 150.

  The information processing unit 150 performs the functions of the communication device 100 by performing various processes. The process performed by the information processing unit 150 includes a process for generating a vehicle position SSID including its own apparatus position information, and a process for controlling broadcast transmission of a communication frame including the generated vehicle position SSID. The processing performed by the information processing unit 150 includes vehicle position information presentation processing based on the own device position and other device position information included in the vehicle position SSID received by the wireless transmission / reception unit 110.

  Details of the vehicle position SSID generation process, the vehicle position SSID broadcast control process, and the vehicle position information presentation process executed by the information processing unit 150 will be described later.

<Information stored in the storage unit 130>
Next, information stored in the storage unit 130 will be described.

  As shown in FIG. 2, the storage unit 130 stores map information MPI and vehicle position information CPI. In the present embodiment, the map information MPI includes road shape data that represents the shape of the road with links and nodes (intersections, etc.), road peripheral data that represents buildings around the road, road gradient, road width, and the like. ing.

  In the present embodiment, the vehicle position information CPI includes own apparatus position information (latitude, longitude) and accuracy, single-hop position (SHP) information, and multi-hop position (MHP) information. Here, the positioning result by the position detection unit 120 is stored as the own apparatus position information. Further, the SHP information and the MHP information are other apparatus position information.

  The single hop position (SHP) information includes SHP # p (latitude, longitude) (p = 1, 2,...). FIG. 2 shows an example in which the number of SHPs in the SHP information is P. The “latitude” in SHP is composed of north / south latitude (N / S) identification information and a numerical value up to the sixth decimal place in decimal notation. In addition, “longitude” in SHP is composed of identification information of east longitude / west longitude and numerical values up to the sixth decimal place in decimal notation.

  The multi-hop position (MHP) information includes MHP # q (latitude, longitude) (q = 1, 2,...). FIG. 2 shows an example in which the number of MHPs in the MHP information is Q. The “latitude” in the MHP is composed of north / south latitude (N / S) identification information and a numerical value up to the sixth decimal place in decimal notation. In addition, “longitude” in MHP is composed of identification information of east longitude / west longitude and numerical values up to the sixth decimal place in decimal notation.

<Configuration of broadcast transmission frame including vehicle position information>
FIG. 3 shows a configuration example of the vehicle position SSID in the broadcast transmission frame including the vehicle position information. As shown in FIG. 3, the vehicle position SSID includes a two-character header. In the present embodiment, “p @” is adopted as the header.

  The vehicle position SSID includes transmission device position information (latitude, longitude) of 12 characters following the header. Here, the transmission device position information at the vehicle position SSID is obtained by converting the own device position information (latitude, longitude) in the storage unit of the device that transmits the vehicle position SSID into a 92-ary display using 92 types of codes. ing. For this reason, the transmission device position information is position information with accuracy within 1 [m]. The position corresponding to the transmission apparatus position information in the vehicle position SSID is handled as SHP in the apparatus that has received the vehicle position SSID.

  The vehicle position SSID can include relative position information with respect to the own apparatus position (transmission apparatus position) of one or more and six or less other apparatuses following the transmission apparatus position information. Each of the relative position information of the other devices is displayed in 92-ary notation and is expressed by three characters. In the present embodiment, the relative position information of the other apparatus represents the distance in the east-west direction and the distance in the north-south direction from the own apparatus position (transmitting apparatus position) in units of 1 [m].

  The position corresponding to the other apparatus position information in the vehicle position SSID is handled as MHP in the apparatus that has received the vehicle position SSID.

<Relative position of other device at vehicle position SSID>
Next, the relative position of the other device at the vehicle position SSID will be described.

  First, a latitude difference ΔΘ and a longitude difference ΔΦ are calculated based on the own device position (latitude (Θ), longitude (Φ)) in the storage unit of the communication device that generates the vehicle position SSID and SHP (latitude, longitude). To do. Here, the latitude difference ΔΘ is positive when the latitude of the device position is north of the latitude of SHP, and the latitude difference ΔΘ is negative when the latitude of the device position is south of the latitude of SHP. To be. In addition, when the longitude of the device position is east of the longitude of SHP, the longitude difference Δθ is positive, and when the latitude of the device position is west of the latitude of SHP, the latitude difference Δθ is negative. Like that.

Next, the latitude difference Δθ and longitude difference Δφ obtained by displaying the latitude difference ΔΘ and longitude difference ΔΦ in the arc method are calculated by the following equations (1) and (2).
Δθ = ΔΘ · (π / 180) (1)
Δφ = ΔΦ · (π / 180) (2)

Subsequently, the distance ΔN ⁽¹⁾ corresponding to the latitude difference Δθ and the distance ΔE ⁽¹⁾ corresponding to the longitude difference Δφ are calculated by the following equations (3) and (4). For less than 1 [m], the first decimal place is rounded off and an integer value with 1 [m] as the unit is calculated.
ΔN ⁽¹⁾ = R _E · Δθ · 1000 (3)
ΔE ⁽¹⁾ = R _E · cos Θ · Δφ · 1000 (4)
Here, the constant R _E is the earth radius expressed in “km” as a unit.

Now, as indicated by a solid line in FIG. 4A, the own apparatus position is the origin O ⁽¹⁾ , the E ⁽¹⁾ axis is positive in the east direction from the origin O ⁽¹⁾ , and the origin O ^{(1 )} and N ⁽¹⁾ coordinates the coordinates adopted the shafting system L ⁽¹⁾ to the north direction as the positive direction from. When such a coordinate system L ⁽¹⁾ is adopted, the coordinate values of the coordinate position P of the SHP are (ΔE ⁽¹⁾ , ΔN ⁽¹⁾ ).

Here, the distance ΔE ⁽¹⁾ may be “positive” or may be “negative”. In addition, the distance ΔN ⁽¹⁾ may be “positive” or may be “negative”.

Now, the region where SHP exists for the device itself is the inner region of a circle centered on the origin O ⁽¹⁾ and having a radius of 350 [m]. Therefore, values ΔE ⁽²⁾ and ΔN ⁽²⁾ that are guaranteed to be positive values are calculated by the following equations (5) and (6).
ΔE ⁽²⁾ = ΔE ⁽¹⁾ +350 (5)
ΔN ⁽²⁾ = ΔN ⁽¹⁾ +350 (6)

The values (ΔE ⁽²⁾ , ΔN ⁽²⁾ ) are the coordinate values of the coordinate position P of the SHP in the coordinate system L ⁽²⁾ indicated by the broken line in FIG.

The values ΔE ⁽²⁾ and ΔN ⁽²⁾ calculated in this way are integers in the range represented by the following equations (7) and (8).
0 ≦ ΔE ⁽²⁾ ≦ 700 (7)
0 ≦ ΔN ⁽²⁾ ≦ 700 (8)

Subsequently, the value NE is calculated by the following equation (9).
NE = ΔN ⁽²⁾ × 1000 + ΔE ⁽²⁾ (9)

In the value NE calculated in this way, ΔN ⁽²⁾ is represented by the upper three digits of decimal display, and ΔE ⁽²⁾ is represented by the lower three digits. The value NE is a numerical value in the range represented by the following equation (10).
0 ≦ NE ≦ 700 700 <92 ³ (10)

For this reason, the value NE uniquely related to the values (ΔE ⁽²⁾ , ΔN ⁽²⁾ ), and thus the distances (ΔE ⁽¹⁾ , ΔN ⁽¹⁾ )) is expressed by three characters when expressed in 92-ary notation be able to. Therefore, in the present embodiment, the value NE calculated using the above-described (1), (2), (3), (4), (5), (6), and (9) is displayed in a 92-adic display. By converting, the relative position information of the other device at the vehicle position SSID is calculated.

  Based on the relative position information of the other device at the vehicle position SSID calculated in this way, the position (latitude, longitude) of the other device can be restored by the restoration process that executes the reverse process of the above-described calculation process. . In the restoration process, first, the relative position information of the other device in the 92-position display at the vehicle position SSID is converted into the value NE in the decimal display.

Subsequently, the value ΔN ⁽²⁾ is specified from the upper three digits of the value NE, and the value ΔE ⁽²⁾ is specified from the lower three digits. The values (ΔE ⁽²⁾ , ΔN ⁽²⁾ ) thus specified are the coordinate values of the other apparatus position P in the coordinate system L ⁽²⁾ indicated by the solid line in FIG.

Next, based on the values ΔE ⁽²⁾ and ΔN ⁽²⁾ , the distances ΔE ⁽¹⁾ and ΔN ⁽¹⁾ are calculated by the following equations (11) and (12).
ΔE ⁽¹⁾ = ΔE ⁽²⁾ −350 (11)
ΔN ⁽¹⁾ = ΔN ⁽²⁾ −350 (12)
The values (ΔE ⁽¹⁾ , ΔN ⁽¹⁾ ) calculated in this way are the coordinate system L ⁽¹⁾ (the origin O ⁽¹⁾ indicated by a broken line in FIG. Is the coordinate value of the other apparatus position P at the position corresponding to.

Next, the latitude difference ΔΘ between the own device position (latitude (Θ), longitude (Φ)) obtained by converting the own device position information in the vehicle position SSID into decimal display, and the other device position (latitude, longitude), The longitude difference ΔΦ is calculated by the following equations (13) and (14).
ΔΘ = ΔN ⁽¹⁾ · 180 / (1000 · R _E · π) (13)
ΔΦ = ΔE ⁽¹⁾ · 180 / (1000 · R _E · π · cos Θ) (14)
From the thus calculated (ΔΘ, ΔΦ) and the own device position (latitude (Θ), longitude (Φ)), the other device position (latitude, longitude) is restored.

[Operation]
Next, with respect to the operation of the communication apparatus 100 configured as described above, the vehicle position SSID generation process executed by the information processing unit 150, the broadcast transmission control process of the generated vehicle position SSID, and the vehicle position The description will be given mainly focusing on the information presentation process.

  Note that the wireless transmission / reception unit 110 has started operation, and when a new SSID is received from another device, the information processing unit 150 converts the received SSID data regardless of whether or not the SSID is a vehicle position SSID. Shall be sent to Further, it is assumed that the position detection unit 120 has started operation and is ready to send the latest positioning result to the information processing unit 150 in response to a current position acquisition request from the information processing unit 150.

<Vehicle position SSID generation process and vehicle position SSID broadcast transmission control process>
First, a vehicle position SSID generation process and a vehicle position SSID broadcast transmission control process will be described.

  In this process, as shown in FIG. 5, the information processing unit 150 first determines whether or not it is the transmission timing of new vehicle position information in step S11. This determination is performed by determining whether or not the display processing of the vehicle position information in step S36, which will be described later, in the current processing cycle period is completed. If the result of the determination in step S11 is negative (step S11: N), the process of step S11 is repeated.

  When the transmission timing of new vehicle position information is reached and the result of determination in step S11 is affirmative (step S11: Y), the process proceeds to step S12. In step S <b> 12, the information processing unit 150 acquires the position information (latitude, longitude) and accuracy of the own apparatus, which is the latest positioning result, from the position detection unit 120. Then, the information processing unit 150 updates the own device position information and accuracy in the storage unit 130 to the acquired own device position information and accuracy.

  Next, in step S <b> 13, the information processing unit 150 determines whether or not the accuracy of the acquired apparatus position information is “high”. If the result of the determination in step S13 is negative (step S13: N), the process returns to step S11 without executing the processes of steps S14 to S22 described later.

  If the result of the determination in step S13 is affirmative (step S13: Y), the process proceeds to step S14. In step S <b> 14, the information processing unit 150 reads SHP information from the storage unit 130. In the following description, it is assumed that P SHPs (SHP # 1 to SHP # P) are registered in the SHP information.

Next, in step S15, the information processing section 150 calculates the transmission device position information by converting the own device position (latitude, longitude) into a 92-ary display. Subsequently, for each of the read SHPs # 1 to #P, the information processing unit 150, as described above, the own device position (latitude and longitude) and each of the SHPs # 1 to #P (latitude and longitude). based on, by converting the value NE ₁ ~NE _P for each of the SHP # 1~ # P to 92 binary representation, and calculates the relative location information for each of the apparatus of SHP # 1~ # P.

  Next, in step S <b> 16, the information processing unit 150 determines whether or not the value P is “6” or less. If the result of the determination in step S16 is negative (step S16: N), the process proceeds to step S17.

  In step S <b> 17, the information processing unit 150 generates a vehicle position SSID in which six of the header (“p @”), the transmission device position information, and the relative position information of the untransmitted SHP are sequentially arranged. Subsequently, in step S <b> 18, the information processing unit 150 transmits a broadcast frame including the generated vehicle position SSID to the outside via the wireless transmission / reception unit 110.

  Next, in step S19, the information processing section 150 decreases the value P by “6”. Then, the process returns to step S16. Thereafter, the processes in steps S16 to S19 are repeated until the result of the determination in step S16 becomes affirmative.

  If the result of the determination in step S16 is affirmative (step S16: Y), the process proceeds to step S20. In step S20, the information processing unit 150 generates a vehicle position SSID in which all of the header (“p @”), the transmission device position information, and the relative position information of the untransmitted SHP are sequentially arranged. Subsequently, in step S <b> 21, the information processing unit 150 transmits a broadcast frame including the generated vehicle position SSID to the outside via the wireless transmission / reception unit 110.

  Next, in step S22, the information processing unit 150 clears the SHP information and MHP information in the storage unit 130. Then, the process returns to step S11. Thereafter, the processes of steps S11 to S22 are repeated.

  In the processing of steps S11 to S22 described above, when the value P determined in the first step S16 is “0” (that is, when SHP is not registered in the storage unit 130), In step S20, a vehicle position SSID in which only the header (“p @”) and the transmission device position information are sequentially arranged is generated.

<Reception processing of vehicle position SSID>
Next, the reception process of the vehicle position SSID will be described.

  In the vehicle position SSID reception process, as shown in FIG. 6, first, in step S31, the information processing unit 150 determines whether or not the current collection period of vehicle position information has ended. It is determined by whether or not a predetermined time has elapsed since the start of. If the result of the determination at step S31 is negative (step S31: N), the process proceeds to step S32.

Note that the “predetermined time” indicates that the change in the position of the vehicles CR ₀ , CR ₁ ,. 1 [m] or so, and from the viewpoint that the vehicle position SSID transmitted from other peripheral communication devices can be collected based on experiments, simulations, experiences, etc. Determined.

  In step S32, the information processing unit 150 determines whether or not the vehicle position SSID has been received based on whether or not the first two characters of the received SSID are “p @ (header of vehicle position SSID)”. If the result of the determination in step S32 is negative (step S32: N), the process returns to step S31.

When the vehicle position SSID is received and the result of determination in step S32 is affirmative (step S32: Y), the process proceeds to step S33. In step S33, the information processing unit 150 can reach the distance D _MAX from the position corresponding to the transmission apparatus position information in the vehicle position SSID to the own apparatus position corresponding to the own apparatus position information in the storage unit 130. It is determined whether or not (= 350 [m]) or less.

  In the determination in step S33, the information processing unit 150 first converts the transmission device position information (latitude, longitude) displayed in 92 notation in the vehicle position SSID into the transmission device position (latitude, longitude) displayed in decimal. Subsequently, the information processing unit 150 calculates a latitude difference and a longitude difference between the own apparatus position (latitude, longitude) and the transmission apparatus position (latitude, longitude).

Next, the information processing section 150 sets the distances (ΔE ⁽¹⁾ , ΔN ⁽¹ ) according to the above-described equations (1) to (4), with (ΔΘ, ΔΦ) being the (latency difference, longitude difference) thus calculated. ⁾ ) Is calculated. Subsequently, the information processing section 150 has a two-dimensional distance ((ΔE ⁽¹⁾ ) ² + (ΔN ⁽¹⁾ ) ² ) ^1/2 represented by the calculated distance (ΔE ⁽¹⁾ , ΔN ⁽¹⁾ ). There determines is by determining whether or not the condition of the following equation (15), the distance from the transmitter position to the own device location is less available maximum distance D _MAX reached.
((ΔE ⁽¹⁾ ) ² + (ΔN ⁽¹⁾ ) ² ) ^1/2 ≦ D _MAX (15)

  If the determination result of step S33 is negative (step S33: N), the process returns to step S31. On the other hand, when the result of the determination in step S33 is affirmative (step S33: Y), the process proceeds to step S34.

  In step S34, the information processing unit 150 restores positions (latitude and longitude) corresponding to each of the relative position information in the vehicle position SSID. At the time of the restoration, the information processing unit 150 executes the restoration process described above based on the decimal display transmission device position (latitude, longitude) obtained by the conversion described above and the relative position information in the vehicle position SSID. .

  Next, in step S35, the information processing unit 150 performs registration processing in the storage unit 130 of positions (latitude and longitude) corresponding to the transmission device position (latitude and longitude) and the relative position information in the vehicle position SSID. . This registration process will be described later.

  When the process of step S35 ends, the process returns to step S31. And the process of step S31-S35 is repeated until the result of determination in step S31 becomes affirmative.

  When the current collection period ends and the result of the determination in step S31 is affirmative (step S31: Y), the process proceeds to step S36. In this step S36, the information processing unit 150 automatically performs registration based on the registration information in the vehicle position information CPI in the storage unit 130 (that is, the vehicle position information acquired during the current collection period) and the map information MPI. Display data for displaying a vehicle position and other nearby vehicle positions on a map is generated. Then, the information processing unit 150 sends the generated display data to the display unit 140. As a result, the display unit 140 displays an image in which the vehicle position and other nearby vehicle positions are displayed on the map.

  Next, in step S37, the information processing section 150 waits for the end of the process in step S36 to be executed after waiting for the end of the process in step S36, and then waits for the end of the process in step S22. Start the collection period. Then, the process returns to step S31. Thereafter, the processes of steps S31 to S37 are repeated.

<Registration process in step S35>
Next, the registration process in step S35 will be described.

  In the registration process, as shown in FIG. 7, first, in step S41, the transmission device position ((latitude, longitude): current SHP for the information processing unit 150) is stored in the SHP information in the storage unit 130. The information processing unit 150 determines whether it can be said that the position of the same vehicle as any SHP. At the time of the determination in step S41, the information processing unit 150 calculates a two-dimensional distance between the transmission device position and each of the SHPs in the SHP information in the same manner as in step S33 described above. Then, by determining whether or not the calculated two-dimensional distance is equal to or less than the predetermined distance, the information processing unit 150 determines whether or not the transmission device position can be said to be the same vehicle position as any SHP in the SHP information. judge.

  Note that the “predetermined distance” is based on experiments, simulations, experiences, etc., from the viewpoint that it can be determined that the vehicle is at the same position even when traveling at a normal traveling speed over the predetermined time described above. Predetermined.

  If the result of the determination in step S41 is affirmative (step S41: Y), the process proceeds to step S46 described later. On the other hand, when the result of the determination in step S41 is negative (step S41: N), the process proceeds to step S43. In step S43, the information processing unit 150 additionally registers the transmission device position as a new SHP.

  Next, in step S <b> 44, the information processing unit 150 determines whether or not the transmission device position is the same vehicle position as any MHP in the MHP information in the storage unit 130. In the determination of step S44, the information processing unit 150 determines whether or not the transmission device position can be said to be the position of the same vehicle as any MHP in the MHP information, as in the case of step S41 described above.

  If the result of the determination in step S44 is negative (step S44: N), the process proceeds to step S46. On the other hand, when the result of the determination in step S44 is affirmative (step S44: Y), the process proceeds to step S45.

  In step S45, the information processing unit 150 deletes the MHP determined to be the same vehicle position as the transmission device position. Then, the process proceeds to step S46.

  In step S46, the information processing unit 150 determines each of the positions corresponding to the relative position information at the vehicle position SSID ((latitude, longitude: current MHP for the information processing unit 150)) and the vehicle position information CPI in the storage unit 130. A position that cannot be said to be the position of the same vehicle is extracted from each of the positions registered in the system (the own apparatus position, SHP, and DHP). Subsequently, in step S47, the information processing unit 150 additionally registers the extracted position as new MHP in the MHP information.

  When the process of step S47 ends, the process of step S35 ends. And a process returns to step S31 of FIG. 6 mentioned above.

  In addition, the example of a display in the display part 140 of the image by which the own vehicle position and the surrounding other vehicle position were displayed on the map is shown by FIG. Here, the own vehicle position is indicated by “●”, and the other vehicle position is indicated by “◯”.

  As described above, in the communication device 100 according to the present embodiment, the information processing unit 150 transmits the vehicle position information transmitted from the position detection unit 120 when exchanging the vehicle position information using the wireless communication between vehicles according to the WiFi standard. The apparatus position information and other apparatus transmission position information including the position information of the other communication apparatus (transmitting apparatus position information) transmitted from the other communication apparatus via the wireless transmission / reception unit 110 are acquired. Subsequently, based on the acquired own device position information and other device transmission position information, the information processing unit 150 includes composite position information (vehicle position SSID) including the own device position information and the relative position information of the other communication device with respect to the own device. ) Is generated. Then, the information processing unit 150 transmits the generated composite position information to the outside using the wireless transmission / reception unit 110.

  Therefore, the number of vehicle position information that can be transmitted in one communication frame can be increased, and the communication efficiency of position information by multi-hop communication between vehicles can be improved.

  Further, in the communication device 100 of the present embodiment, the own device position information to be transmitted is latitude information and longitude information, has a number of digits determined by a predetermined position accuracy, and is relative position information of other communication devices. Has the number of digits determined by the predetermined position accuracy and the longest reachable distance of the wireless signal of the short-range wireless communication according to the WiFi standard. For this reason, the communication efficiency of the positional information by the multihop communication between vehicles can be improved reasonably.

  Further, in the present embodiment, even when the relative position information of at least one other communication apparatus different from the other communication apparatus with respect to the other communication apparatus is included in the other apparatus transmission position information, the composite position information includes the corresponding information for the own apparatus. The relative position information of the communication device is not included. For this reason, the number of pieces of information on the vehicle position to be transmitted can be rationally suppressed.

  In the present embodiment, when it is determined that the position reflected in the one relative position information in the other apparatus transmission position information is the position of the own apparatus, the information processing unit 150 determines from the other apparatus transmission position information. Compound position information is generated based on the information excluding the one relative position information and the position information of the device itself. For this reason, since the composite position information includes only one type of own apparatus position information, transmission of overlapping position information can be prevented.

  Further, in the present embodiment, the information processing unit 150 further acquires the accuracy of the own device position detected by the position detection unit 120. If it is determined that the own apparatus position does not have a predetermined allowable accuracy, the information processing unit 150 does not generate composite position information and transmit composite position information. Yes. For this reason, transmission of vehicle position information that does not have acceptable accuracy can be prevented.

  Further, in the present embodiment, when there are a plurality of pieces of position information of the same apparatus in the position information of the apparatuses included in the plurality of other apparatus transmission position information transmitted from a plurality of other communication apparatuses, the information processing unit 150 One of the plurality of pieces of position information of the same device is adopted to generate composite position information. For this reason, transmission of overlapping position information can be prevented.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment, and various modifications are possible.

  For example, in the above-described embodiment, the WiFi standard is adopted as a standard for wireless communication between apparatuses. However, the present invention can also be applied when another short-range wireless communication standard is adopted.

  In the above embodiment, the position detection result in each device is displayed in decimal. However, other types of display may be used.

  In the above embodiment, the communication device is arranged in the vehicle. However, the communication device may be arranged in a moving body other than the vehicle.

  In the above embodiment, the longest reachable distance is 350 [m]. However, the longest reachable distance may be determined by experiments or the like.

  In the above-described embodiment, the relative position of the other device with respect to the own device is expressed using orthogonal coordinates, but may be expressed using polar coordinates.

  In the above embodiment, the relative position information related to the MHP in the storage unit 130 is not included in the vehicle position SSID. However, the relative position information related to the MHP is also included in the vehicle position SSID and transmitted to the outside. Information may be transmitted.

  In the embodiment described above, when there are a number of pieces of vehicle position information to be transmitted that cannot be included in one vehicle position SSID, the information is divided into a plurality of vehicle positions SSID and transmitted. On the other hand, the number of pieces of vehicle position information to be transmitted may be limited to the number that can be included in one vehicle position SSID. In this case, for example, the vehicle position information to be transmitted can be selected by increasing the priority as it is closer to the own device position.

  Note that the information processing unit in the above embodiment is configured as a computer as a calculation unit including a central processing unit (CPU) and the like, and information prepared by executing a program prepared in advance on the computer is obtained. Part or all of the processing in the processing unit may be executed. This program is recorded on a computer-readable recording medium such as a hard disk, CD-ROM, or DVD, and is loaded from the recording medium and executed by the computer. The program may be acquired in a form recorded on a portable recording medium such as a CD-ROM or DVD, or may be acquired in a form distributed via a network such as the Internet. Also good.

DESCRIPTION OF SYMBOLS 100 ... Communication apparatus 110 ... Wireless transmission / reception part (transmission / reception part)
150 ... Information processing unit (acquisition unit, information generation unit)

Claims (9)

A transmission / reception unit that transmits and receives information by short-range wireless communication;
An acquisition unit for acquiring the other device transmission position information including the position information of the other communication device transmitted from the other communication device using the transmission / reception unit, and the position information of the own device;
Based on the position information of the own apparatus acquired by the acquisition unit and the other apparatus transmission position information, generate composite position information including the position information of the own apparatus and the relative position information of the other communication apparatus with respect to the own apparatus, An information generation unit that transmits the generated composite position information to the outside using the transmission / reception unit;
A communication apparatus comprising: The position information of the own device is latitude information and longitude information, and has a number of digits determined by a predetermined position accuracy,
The relative position information of the other communication device has the number of digits determined by the predetermined position accuracy and the longest reachable distance of the radio signal of the short-range wireless communication.
The communication apparatus according to claim 1.   Even when the relative position information of at least one other communication apparatus with respect to the other communication apparatus is included in the other apparatus transmission position information, the composite position information does not include the relative position information of the other communication apparatus with respect to the own apparatus. The communication apparatus according to claim 1 or 2, wherein   When it is determined that the position reflected in the one relative position information in the other apparatus transmission position information is the position of the own apparatus, the information generator generates the one relative position from the other apparatus transmission position information. The communication apparatus according to claim 1, wherein the composite position information is generated based on information excluding position information and position information of the own apparatus acquired by the acquisition unit. The acquisition unit further acquires the accuracy of the position information of the device,
When it is determined that the position information of the device does not have a predetermined allowable accuracy, the information generation unit does not generate the composite position information and does not transmit the composite position information. The communication apparatus according to any one of claims 1 to 4, wherein   When the number of the other communication devices is plural, and there are plural pieces of position information of the same device in the position information of the devices included in the plurality of other device transmission position information, the information generation unit The communication apparatus according to claim 1, wherein the composite position information is generated by employing one of the position information. A transmission / reception unit for transmitting / receiving information by short-range wireless communication; other device transmission position information including position information of the other communication device transmitted from the other communication device using the transmission / reception unit, and position information of the own device A communication method used in a communication device comprising:
Generation for generating composite position information including the position information of the own apparatus and the relative position information of the other communication apparatus with respect to the own apparatus based on the position information of the own apparatus and the other apparatus transmission position information acquired by the acquisition unit Process and;
A transmission step of transmitting the generated composite position information to the outside using the transmission / reception unit;
A communication method comprising:   A communication program causing a computer included in the communication apparatus to execute the communication method according to claim 7.   9. A recording medium on which the communication program according to claim 8 is recorded so as to be readable by a computer included in the communication device.

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