JP7397108B2 - Receiving device and location identification method - Google Patents

Description

The present invention relates to a receiving device, a position specifying method, and a position specifying program.

2. Description of the Related Art Conventionally, communication using wireless LAN communication has been performed between an access point (AP) device and a terminal device, or between one terminal device and another. In such wireless LAN communications, location information is often exchanged between wireless LAN communication devices.

When exchanging such location information, a technique is known in which information reflecting the positioning result of the wireless LAN communication device's own location is included and transmitted in a service set identifier (SSID) whose information content can be freely defined. This SSID can include information for up to 32 characters. Here, one of 94 types of codes including codes corresponding to "0" to "9" can be selected for each character.

By the way, when positioning a wireless LAN communication device using GPS (Global Positioning System) satellites, latitude and longitude information can be obtained in decimal format up to 8 decimal places. Common. In order to represent such positioning results in decimal notation, if a code corresponding to "0" to "9" is adopted, at least 23 of the 32 characters in the SSID, including the distinction between north latitude/south latitude and east longitude/west longitude, will be used. letters will be used. In this case, of the 23 characters, 11 characters are used for latitude information and 12 characters are used for longitude information.

Now, since the information content of the SSID can be freely defined, it is preferable that the number of characters used for one purpose be small. Therefore, a technique has been proposed that can reduce the number of characters used to transmit location information using an SSID (see Patent Document 1: hereinafter referred to as "prior art").

In this conventional technique, when transmitting position information simultaneously, each of the latitude information and longitude information is converted into sexagesimal representation and entered into the SSID. A wireless LAN communication device that receives location information stored in such an SSID is configured to decipher the latitude and longitude information displayed in hexadecimal.

Japanese Patent Application Publication No. 2009-089395

In the conventional technology described above, the latitude information and longitude information are expressed in sexagesimal notation, so the number of characters used for position information can be reduced compared to the case where they are expressed in decimal notation. As a result, according to the conventional technique, the amount of communication used for transmitting and receiving position information can be made more efficient than when the position information is expressed in decimal notation.

However, in the conventional technology, although improvements have been made in displaying location information, the contents of the location information exchanged are general-purpose. Therefore, there is a need for a technology that can improve the efficiency of transmitting and receiving location information by optimizing the location information to be transmitted and received in consideration of the special characteristics of short-range wireless communication. Meeting such demands is one of the problems to be solved by the present invention.

The invention according to claim 1 provides latitude information and longitude information indicating the current location of another device, the information being latitude information and longitude information indicating the current location of another device, and according to the longest possible reachable distance corresponding to a wireless communication method adopted in wireless communication with the other device. from the first digit when expressed in decimal notation, to the second digit lower than the first digit, which is determined according to the specific accuracy to be achieved for the latitude information and longitude information where the other device is located. a receiving unit that receives transmitter position information, which is information for a predetermined number of digits; latitude information and longitude information of the own device, which can specify the position of the own device on the earth; a receiving side position detection unit that detects receiving side position information including information from the most significant digit to the second digit when expressed as; provisional transmission based on the transmitting side position information and the receiving side position information; After calculating the position information, calculate the latitude distance and longitude distance between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information, and calculate the calculated distance and the longest reachable distance. and a specifying unit that specifies the latitude and longitude of the other device based on; the first digit has a value of a digit one digit above the first digit that differs by "1", and When the values of the other digits are the same, the distance between latitudes at the same longitude is determined to be longer than the longest reachable distance, and the value of the second digit is "1". and the values of other digits are the same, the distance between latitudes at the same longitude and the distance between longitudes at the same latitude are both determined to be less than or equal to the distance of the specific accuracy level, and the specifying section is , the distance between latitude and longitude between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information are compared with the longest possible reachable distance, and the provisional position information is determined to be appropriate. If the provisional location information is appropriate, the latitude and longitude of the provisional transmission location information are specified as the latitude and longitude of the other device, and the provisional transmission location information includes A first provisional information obtained by combining the latitude upper digit part, which is a part of higher digits than the first digit in the decimal representation of the latitude information of the side location information, and the latitude information in the decimal representation of the sending side location information. The transmitting side latitude is included, and the specifying unit determines that the first inter-latitude distance at the same longitude between the receiving side latitude determined from the latitude information of the receiving side position information and the first provisional sending side latitude is the longest reachable distance. If it is shorter, the first provisional sending side latitude is specified as the latitude of the other device, and the receiving side latitude determined from the latitude information of the receiving side position information is the same as the first provisional sending side latitude. When the distance between latitudes in longitude is longer than the longest reachable distance, the latitude correction value is set to "1" for the lowest digit of the upper latitude digit part and "0" for the other digits. A second provisional sending side latitude is calculated by adding it to the provisional sending side latitude, and the second inter-latitude distance between the receiving side latitude and the second provisional sending side latitude in the case of the same longitude is the maximum reachable distance. , the second provisional sending side latitude is specified as the latitude of the other device, and if the distance between the second latitudes is longer than the maximum reachable distance, the latitude correction value is specified as the first provisional latitude. A third provisional sender latitude is calculated by subtracting it from the sender's latitude, and a third inter-latitude distance between the receiver's latitude and the third provisional sender's latitude in the case of the same longitude is less than the longest reachable distance. The receiving device is characterized in that when the latitude of the other device is short, the third provisional sending side latitude is specified as the latitude of the other device .
The invention according to claim 2 provides latitude information and longitude information indicating the current location of another device, the information being latitude information and longitude information indicating the current location of another device, and according to a maximum reachable distance corresponding to a wireless communication method adopted in wireless communication with the other device. from the first digit when expressed in decimal notation, to the second digit lower than the first digit, which is determined according to the specific accuracy to be achieved for the latitude information and longitude information where the other device is located. a receiving unit that receives transmitter position information, which is information for a predetermined number of digits; latitude information and longitude information of the own device, which can specify the position of the own device on the earth; a receiving side position detection unit that detects receiving side position information including information from the most significant digit to the second digit when expressed as; provisional transmission based on the transmitting side position information and the receiving side position information; After calculating the position information, calculate the latitude distance and longitude distance between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information, and calculate the calculated distance and the longest reachable distance. and a specifying unit that specifies the latitude and longitude of the other device based on; the first digit has a value of a digit one digit above the first digit that differs by "1", and When the values of the other digits are the same, the distance between latitudes at the same longitude is determined to be longer than the longest reachable distance, and the value of the second digit is "1". and the values of other digits are the same, the distance between latitudes at the same longitude and the distance between longitudes at the same latitude are both determined to be less than or equal to the distance of the specific accuracy level, and the specifying section is , the distance between latitude and longitude between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information are compared with the longest possible reachable distance, and the provisional position information is determined to be appropriate. If the provisional location information is appropriate, the latitude and longitude of the provisional transmission location information are specified as the latitude and longitude of the other device, and the provisional transmission location information includes First provisional longitude information obtained by combining the longitude upper digit part, which is the part of the digits higher than the first digit in the decimal representation of the longitude information of the side position information, and the longitude information in the decimal representation of the transmitter side position information. A transmitting side longitude is included, and the specifying unit is configured to determine the receiving side latitude determined from the receiving side longitude determined from the receiving side longitude information of the receiving side position information and the first provisional transmitting side longitude, and the receiving side latitude determined from the latitude information of the receiving side position information. If the first longitude distance is shorter than the longest reachable distance, the first provisional transmitting side longitude is specified as the longitude of the other device, and the receiving side longitude is determined from the longitude information of the receiving side position information. , if the longitude distance between the first provisional sender's longitude and the receiver's latitude is longer than the longest reachable distance, set the least significant digit of the upper digits of the longitude to "1" and set the other digits to "1". A second provisional sending side longitude is calculated by adding the longitude correction value set to "0" to the first provisional sending side longitude, and the receiving side longitude and the second provisional sending side longitude at the receiving side latitude are When the distance between the second longitudes is shorter than the longest reachable distance, the second provisional sender longitude is specified as the longitude of the other device, and the second longitude distance is longer than the longest reachable distance. , the longitude correction value is subtracted from the first provisional sending side longitude to calculate a third provisional sending side longitude, and the distance between the receiving side longitude and the third provisional sending side longitude at the receiving side latitude is calculated. The receiving device is characterized in that when the third longitude distance is shorter than the longest reachable distance, the third provisional transmitting side longitude is specified as the latitude of the other device.

The invention according to claim 5 provides latitude information and longitude information indicating the current position of another device, the information being stored according to the longest possible reachable distance corresponding to a wireless communication method adopted in wireless communication with the other device. A predetermined number of digits from the first digit expressed in decimal system to the second digit lower than the first digit to be realized for the latitude information and longitude information where the other device is located. a receiving unit that receives transmitter position information, which is information; latitude information and longitude information of the own device, which can specify the position of the own device on the earth, and when expressed in decimal notation, the highest A receiving side position detection unit that detects receiving side position information including information from a digit to the second digit; an acquisition step of acquiring position information and receiving side position information detected by the receiving side position detecting section; the specifying section detecting provisional transmission position information based on the transmitting side position information and the receiving side position information; After calculating, calculate the distance between latitude and longitude between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information, and based on the calculated distance and the longest possible reachable distance. and specifying the latitude and longitude of the other device; and the first digit is different from the other device in that the value of the digit one digit above the first digit differs by “1”, and When the values of the digits are the same, the distance between latitudes at the same longitude is determined to be longer than the longest reachable distance, and the value of the second digit differs by "1". , and when the values of the other digits are the same, both the distance between latitudes at the same longitude and the distance between longitudes at the same latitude are determined to be less than or equal to the distance of the specific accuracy level, and the specifying step includes the The specifying unit compares the distance between latitudes and longitudes between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information with the longest possible reachable distance, and determines whether the provisional position information is correct. a determination step of determining whether the provisional location information is appropriate; a latitude and longitude identification step of identifying the latitude and longitude of the provisional transmission location information as the latitude and longitude of the other device when the provisional location information is appropriate; ; the provisional transmission position information includes a latitude upper digit part which is a digit higher than the first digit in the decimal representation of the latitude information of the reception side position information, and a decimal part of the latitude information of the transmission side position information. A first provisional sending side latitude obtained by combining latitude information expressed in decimal notation is included, and the latitude and longitude specifying step includes a first provisional sending side latitude determined from latitude information of the receiving side position information and the first provisional sending side latitude. If the distance between the first latitudes at the same longitude is shorter than the longest reachable distance, the specifying unit specifies the first provisional sending side latitude as the latitude of the other device. and; if the distance between the latitudes at the same longitude between the latitude of the receiving side determined from the latitude information of the receiving side position information and the latitude of the first provisional sending side is longer than the maximum reachable distance, the upper digit part of the latitude A latitude correction value with the least significant digit set to "1" and the other digits set to "0" is added to the first provisional sender latitude to calculate the second provisional sender latitude, and in the case of the same longitude, When the second inter-latitude distance between the receiving side latitude and the second provisional sending side latitude is shorter than the maximum reachable distance, specifying the second provisional sending side latitude to the latitude of the other device. a second latitude specifying step; and if the distance between the second latitudes is longer than the longest reachable distance, subtracting the latitude correction value from the first provisional sender latitude to calculate a third provisional sender latitude; However, when the third inter-latitude distance between the receiving side latitude and the third provisional sending side latitude in the case of the same longitude is shorter than the maximum reachable distance, the third provisional sending side latitude is set to the third provisional sending side latitude. A position specifying method is characterized by comprising: a third latitude specifying step of specifying the latitude of the device;

The invention according to claim 6 is a position specifying program that causes a computer included in a receiving device to execute the position specifying method according to claim 5 .
The invention according to claim 7 provides latitude information and longitude information indicating the current location of another device, the information being latitude information and longitude information indicating the current location of another device, and according to the longest reachable distance corresponding to a wireless communication method adopted in wireless communication with the other device. A predetermined number of digits from the first digit expressed in decimal system to the second digit lower than the first digit to be realized for the latitude information and longitude information where the other device is located. a receiving unit that receives transmitter position information, which is information; latitude information and longitude information of the own device, which can specify the position of the own device on the earth, and when expressed in decimal notation, the highest A receiving side position detection unit that detects receiving side position information including information from a digit to the second digit; an acquisition step of acquiring position information and receiving side position information detected by the receiving side position detecting section; the specifying section detecting provisional transmission position information based on the transmitting side position information and the receiving side position information; After calculating, calculate the distance between latitude and longitude between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information, and based on the calculated distance and the longest possible reachable distance. and specifying the latitude and longitude of the other device; and the first digit is different from the other device in that the value of the digit one digit above the first digit differs by “1”, and When the values of the digits are the same, the distance between latitudes at the same longitude is determined to be longer than the longest reachable distance, and the value of the second digit differs by "1". , and when the values of the other digits are the same, both the distance between latitudes at the same longitude and the distance between longitudes at the same latitude are determined to be less than or equal to the distance of the specific accuracy level, and the specifying step includes the The specifying unit compares the distance between latitudes and longitudes between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information with the longest possible reachable distance, and determines whether the provisional position information is correct. a determination step of determining whether the provisional location information is appropriate; a latitude and longitude identification step of identifying the latitude and longitude of the provisional transmission location information as the latitude and longitude of the other device when the provisional location information is appropriate; ; the provisional transmission position information includes a latitude upper digit part which is a digit higher than the first digit in the decimal representation of the latitude information of the reception side position information, and a decimal part of the latitude information of the transmission side position information. The latitude and longitude specifying step includes a first provisional sending side latitude obtained by combining latitude information expressed in decimal notation, and the latitude and longitude specifying step includes the receiving side longitude determined from the longitude information of the receiving side position information and the first provisional sending side longitude. If the first longitude distance at the receiving side latitude determined from the latitude information of the receiving side position information is shorter than the longest reachable distance, the identifying unit sets the first provisional sending side longitude to the other. a first longitude specifying step of specifying the longitude of the device; the longitude distance at the receiving side latitude between the receiving side longitude determined from the longitude information of the receiving side position information and the first provisional transmitting side longitude is the longest reachable distance; If it is longer than the distance, a longitude correction value in which the least significant digit of the upper digit part of the longitude is set to "1" and the other digits are set to "0" is added to the first provisional transmitting side longitude, and the second longitude is calculated. Calculate a provisional transmitting side longitude, and when the second longitude distance between the receiving side longitude and the second provisional sending side longitude at the receiving side latitude is shorter than the longest reachable distance, the second provisional transmission. a second longitude specifying step of specifying the side longitude to the longitude of the other device; if the distance between the second longitudes is longer than the longest reachable distance, the specifying unit sets the longitude correction value to the first longitude; A third provisional sending side longitude is calculated by subtracting it from the provisional sending side longitude, and the third longitude distance between the receiving side longitude and the third provisional sending side longitude at the receiving side latitude is the longest reachable distance. , a third longitude specifying step of specifying the third provisional transmitting side longitude to the latitude of the other device.
The invention according to claim 8 is a position specifying program that causes a computer included in a receiving device to execute the position specifying method according to claim 7.

1 is a diagram for explaining the configuration of a wireless LAN communication device according to an embodiment of the present invention. FIG. 3 is a diagram for explaining position information exchanged between devices. 2 is a flowchart for explaining a process for specifying the location of another device, which is executed by the information processing unit in FIG. 1. FIG. FIG. 4 is a flowchart for explaining the process of specifying the latitude of another device in FIG. 3. FIG. FIG. 3 is a diagram for explaining a first provisional latitude, a second provisional latitude, and a third provisional latitude. FIG. 4 is a flowchart for explaining the process of identifying the longitude of another device in FIG. 3. FIG. FIG. 3 is a diagram for explaining a first provisional longitude, a second provisional longitude, and a third provisional longitude.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.
[composition]
FIG. 1 shows the configuration of a wireless LAN communication device 100 according to an embodiment. As shown in FIG. 1, the wireless LAN communication device 100 is placed inside a vehicle CR ₀ .

This wireless LAN communication device 100 communicates with a wireless LAN communication device 200 _j and an access point device 300 disposed in other vehicles CR _j (j=1,...,N), and a wireless communication device according to the WiFi (Wireless Fidelity) standard. Communication is possible. Here, in Japan, the longest wireless communication distance in wireless communication according to the WiFi standard is about 200 [m]. Therefore, it can be said that wireless communication cannot be performed between devices over a distance of more than 400 [m], which is twice the longest wireless communication distance. Furthermore, when the wireless LAN communication device 100 specifies the positions of other vehicles _{CR 1} , .

In the following explanation, 400 [m] will be referred to as "maximum reachable distance D _MAX ", and this maximum reachable distance D _MAX is determined as described above based on the short-range wireless standards adopted by each country. shall be determined.

By the way, if the latitudes differ by 0.1 degree in decimal notation, the same longitude will result in a distance of 10 [km] or more, regardless of the longitude. Also, if the longitude differs by 0.1 degrees in decimal notation, if the latitude is 0 degrees, they will be separated by a distance of 10 [km] or more as in the case of latitude, but the northernmost If the latitude is 78 degrees north like the city of Sverpard Islands, then the distance will be about 2.3 [km]. Note that there are no cities in the southern hemisphere at latitudes higher than 78 degrees south. Therefore, the maximum reachable distance D _MAX is 1/2 of the distance between latitudes corresponding to 0.1 degrees at the same longitude, and the distance between longitudes corresponding to 0.1 degrees at the latitude where the city is located on the earth. The distance is shorter than 1/2 of either.

Also, if the latitudes differ by 1 x 10 ^-6 degrees in decimal notation, the same longitude will be separated by a distance of about 10 [cm] (approximately 11 [cm]) , no matter what the longitude is. It turns out. Also, if the longitudes differ by 1 x 10 ^-6 degrees in decimal notation, the distance will be about 10 [cm] (approximately 11 [cm]) even if the latitude is 0 degrees at the longest. Become

For this reason, if it is possible to determine a value with the first decimal place or higher in decimal notation between devices that perform wireless communication using the WiFi standard within a city, in order to specify the location of another device, information on the location of the other device can be used. (That is, other device latitude information and other device longitude information), it is sufficient if the latitude information and longitude information can be received in decimal notation for five digits from the second to the sixth decimal place. Therefore, in this embodiment, the latitude and longitude of other devices are determined as described later, and the latitude and longitude information is expressed in decimal notation for five digits from the second decimal place to the sixth decimal place. , to be exchanged between devices.

Note that in this embodiment, each of the wireless LAN communication device 100, the wireless LAN communication device _200j , and the access point device 300 includes a position detection unit. Based on the positioning results (positioning latitude and positioning longitude) obtained by the position detecting unit of each device, each device uses location information (transmission latitude information and transmission longitude information (transmission side latitude information and sending side longitude information)). Here, the position detection section of each device is configured to output the detection result up to the eighth decimal place in decimal notation.

FIG. 2 shows a procedure for generating location information (transmission latitude information and transmission longitude information) included in the SSID broadcasted by each device in this embodiment. Here, FIG. 2A shows a procedure for generating a transmission latitude, and FIG. 2B shows a procedure for generating a transmission longitude.

As shown in FIG. 2A, when generating transmission latitude information, first, five digits from the second decimal place to the sixth decimal place are extracted from the measured latitude. Then, the extracted result is converted into a 94-decimal representation (hereinafter referred to as "94-decimal conversion") to generate transmission latitude information consisting of three characters. The reason why the 94-decimal conversion is performed here is that, as described above, one character from 94 types of codes can be arbitrarily selected as one character in the SSID.

As shown in FIG. 2(B), when generating transmission longitude information, as in the case of generating transmission latitude information, first 5 digits from the second decimal place to the sixth decimal place are extracted from the measured longitude. . Then, the extracted result is converted into a 94-decimal representation (hereinafter referred to as "94-decimal conversion") to generate transmission longitude information consisting of three characters.

Note that a 3-digit 94-decimal display can represent 94 ³ = 830584 (>100000) types of numerical values, so it is guaranteed that a 3-digit 94-decimal display can represent 5 digits in a decimal display. There is. For example, "0-93" in decimal notation is "0-9 a-z A-Z ! "# $ % &' ( ) * + , - . / : ; <> = ? @ ^ _ ` { | } ~ [ ] \” by determining the corresponding 94-decimal number, the decimal representation “23456” can be expressed as the 94-decimal representation “2YN”.

<Configuration of wireless LAN communication device 100>
Next, the configuration of the above wireless LAN communication device 100 will be explained.

Returning to FIG. 1, the wireless LAN communication device 100 includes a wireless transmitting/receiving section 110 and a position detecting section 120. The wireless LAN communication device 100 also includes an information processing section 130.

The wireless transmitter/receiver 110 described above performs wireless communication according to the WiFi standard between the wireless LAN communication device 200 _j (j=1, . . . , N) and external devices such as the access point device 300. When receiving data from an external device, the wireless transmitter/receiver 110 sends the received data to the information processor 130 . Such received data includes an SSID that includes location information (other device location information (sending side location information)) broadcasted by the external device.

Additionally, the wireless transmitter/receiver 110 transmits data sent from the information processor 130 to an external device. Such transmission data includes SSID data that includes location information of the wireless LAN communication device 100.

The position detection unit 120 described above has a GPS positioning function. The self-device position (self-device latitude and self-device longitude), which is the positioning result by the position detection section 120, is sent to the information processing section 130. Note that the latitude of the own device is composed of identification information of northern latitude/southern latitude (N/S) and a numerical value to the eighth decimal place in decimal notation. Further, the longitude of the own device is composed of east longitude/west longitude identification information and a numerical value up to the eighth decimal place in decimal notation.

The information processing unit 130 described above realizes the functions of the wireless LAN communication device 100 by performing various processes. The processing performed by the information processing unit 130 includes processing for generating an SSID that includes location information of the own device, and processing for controlling broadcast transmission of the generated SSID. Further, the processing performed by the information processing unit 130 includes processing for specifying the location of the other device based on the location of the own device and the other device location information included in the SSID received by the wireless transceiver 110.

[motion]
Next, the operation of the wireless LAN communication device 100 configured as described above will be explained, focusing mainly on the process of controlling transmission of own device position information and the process of specifying the position of other devices, executed by the information processing unit 130. do.

It is assumed that the wireless transmitting/receiving unit 110 has started operating, and when receiving a new SSID from another device, it sequentially sends the data of the received SSID to the information processing unit 130. Further, it is assumed that the position detection unit 120 has started operating, and when a new positioning result is obtained, it sequentially sends the new positioning result to the information processing unit 130.

<Transmission control process of own device location information>
The transmission control process of the own device position information is executed every time it is time to broadcast the SSID.

When it comes to the SSID broadcast transmission timing, the information processing unit 130 uses the latest positioning results (positioning latitude and positioning longitude) by the position detection unit 120, that is, the latest position of the own device (the latitude and longitude of the own device). Then, transmit latitude information and transmit longitude information are generated. When generating such transmission latitude information, the information processing unit 130 first extracts five digits from the second decimal place to the sixth decimal place from the latest positioning latitude. Then, the extracted result is converted into 94 base to generate transmission latitude information consisting of three characters (see FIG. 2(A)).

Furthermore, when generating transmission longitude information, the information processing unit 130 first extracts five digits from the second to sixth decimal places from the latest positioning longitude. Then, the extracted result is converted into 94 base to generate transmission longitude information consisting of three characters (see FIG. 2(B)).

When the transmission latitude information and transmission longitude information are generated in this way, the information processing unit 130 generates an SSID including the generated transmission latitude information and transmission longitude information. Then, the generated SSID is sent to the wireless transmitter/receiver 110 along with the fact that it is an SSID. As a result, the SSID including the own device location information for the wireless LAN communication device 100 is broadcast-transmitted from the wireless transmitting/receiving section 110.

<Processing to identify the location of other devices>
In the process of specifying the location of another device, as shown in FIG. By determining whether or not position information (other device latitude information and other device longitude information) sent from another device has been newly received. If the result of the determination in step S11 is negative (step S11: N), the process of step S11 is repeated.

If position information of another device is newly received and the result of the determination in step S11 is affirmative (step S11: Y), the process proceeds to step S12. In this step S12, the information processing unit 130 acquires the current position of the own device, which is the positioning result by the position detection unit 120, that is, the own device position. Here, the own device position is composed of the own device latitude and the own device longitude.

In the following explanation, the value above the first decimal place of the latitude of the own device is written as “LTU _S (≧0.1)”, and the value below the first decimal place of the latitude of the own device is written as “1×10 ^-6 ≦ _LTLS <0.1”. Therefore, the latitude of the own device is expressed as ( _LTUS + _LTLS (= _LTS )).

Further, the value of the longitude of the own device with the first decimal place or higher is written as “LNU _S ”, and the value of the longitude of the own device with the first decimal place or more is written as “LNL _S ”. Therefore, the latitude of the own device is expressed as (LNU _S +LNL _S (=LN _S )).

Next, in step S13, the information processing unit 130 performs processing for specifying the latitude of another device. Note that details of the process for specifying the latitude of another device executed in step S13 will be described later.

Next, in step S14, the information processing unit 130 performs a process of identifying the longitude of another device. Note that details of the process for specifying the longitude of another device executed in step S14 will be described later.

In this way, when the location of the other device that has transmitted the new location information, that is, the other device's latitude and longitude, is specified, the process returns to step S11. Thereafter, the processes of steps S11 to S14 are executed, and each time new location information is received from another device, the location of the other device that has transmitted the new location information is specified.

(Identification process of other device latitude)
Next, the process for specifying the latitude of another device, which is executed in step S13 described above, will be described.

In the process of specifying the latitude of another device, as shown in FIG. 4, first, in step S21, the information processing unit 130, based on the latitude of the own device _LTS (= _LTUS + _LTLS ) and the latitude information of the other device, A first provisional latitude (first provisional sender latitude) FLT is calculated. When calculating the first provisional latitude, the information processing unit 130 first converts the other device's latitude information expressed in 94 decimal notation to decimal notation (hereinafter referred to as "decimal conversion"), A numerical value LTL _T (1×10 ^-6 ≦ _LTLT <0.1) for five digits from the second decimal place to the sixth decimal place of latitude is calculated. Then, the information processing unit 130 calculates the first provisional latitude FLT using the following equation (1).
FLT=LTU _S + _LTLT ...(1)

Subsequently, in step S22, the information processing unit 130 performs a first latitude determination based on the own device latitude _LTS and the first provisional latitude FLT to determine whether the first provisional latitude FLT is appropriate as the other device latitude. When determining the first latitude, the information processing unit 130 calculates a first inter-latitude distance between the own device latitude _LTS and the first provisional latitude FLT in the case of the same longitude. Then, the information processing unit 130 determines whether the first provisional latitude FLT is appropriate as the latitude of another device by determining whether the calculated first latitude-to-latitude distance is less than or equal to the maximum reachable distance _DMAX . Perform a first latitude determination.

Here, the information processing unit 130 calculates the first inter-latitudinal distance according to the Lambert-Andoyer formula. Note that the information processing unit 130 also calculates a second distance between latitudes and a distance between first and second longitudes, which will be described later, according to the Lambert-Andoyer formula.

If the result of the determination in step S22 is positive (step S22: Y), the process proceeds to step S23. In this step S23, the information processing unit 130 specifies the first provisional latitude FLT as the other device latitude.

When the latitude of the other device is specified in this way, the process of step S13 ends. The process then proceeds to step S14 in FIG.

If the result of the determination in step S22 described above is negative (step S22: N), the process proceeds to step S24. In this step S24, the information processing unit 130 calculates the second provisional latitude (second provisional sending side latitude) SLT using the following equation (2).
SLT=(LTU _S +0.1)+ _LTLT ...(2)

Subsequently, in step S25, the information processing unit 130 performs a second latitude determination based on the own device latitude _LTS and the second provisional latitude SLT to determine whether the second provisional latitude SLT is appropriate as the other device latitude. In this second latitude determination, the information processing unit 130 calculates a second inter-latitude distance between the own device latitude _LTS and the second provisional latitude SLT in the case of the same longitude. Then, the information processing unit 130 determines whether the second provisional latitude SLT is appropriate as the other device's latitude by determining whether the calculated second latitude-to-latitude distance is less than or equal to the maximum reachable distance _DMAX . Perform a second latitude determination.

If the result of the determination in step S25 is positive (step S25: Y), the process proceeds to step S26. In this step S26, the information processing unit 130 specifies the second provisional latitude SLT as the latitude of the other device.

When the latitude of the other device is specified in this way, the process of step S13 ends. The process then proceeds to step S14 in FIG.

If the result of the determination in step S25 described above is negative (step S25: N), the process proceeds to step S27. In this step S27, the information processing unit 130 calculates the third provisional latitude (third provisional transmitting side latitude) TLT using the following equation (3).
TLT=(LTU _S -0.1)+ _LTLT ...(3)

In addition, if the third provisional latitude TLT becomes a negative value, if the own device's latitude LT _S is a northern latitude, it will be changed to the southern latitude, and if the own device's latitude LT _S is a southern latitude, it will be changed to the northern latitude. At the same time, the numerical part is set to (0.1- _LTLT ), and the third provisional latitude TLT is set.

Next, in step S28, the information processing unit 130 specifies the third provisional latitude TLT as the other device latitude. When the latitude of the other device is specified in this way, the process of step S13 ends. The process then proceeds to step S14 in FIG.

Note that FIG. 5 schematically shows the calculation procedure of the first to third provisional latitudes described above.

(Specifying longitude of other devices)
Next, the process of specifying the longitude of another device, which is executed in step S14 described above, will be described.

In _{the process} of specifying _the longitude of another device, as shown in FIG. A first provisional longitude (first provisional transmitting side longitude) FLN is calculated. When calculating the first provisional longitude, the information processing unit 130 first converts the longitude information of the other device expressed in 94 decimal to decimal, and converts the longitude information of the other device from the second decimal place to the sixth decimal place. A five-digit numerical value LNL _T (1×10 ^-6 ≦LNL _T <0.1) is calculated. Then, the information processing unit 130 calculates the first provisional longitude FLN using the following equation (4).
FLN=LNU _S +LNL _T …(4)

Subsequently, in step S32, the information processing unit 130 performs a first longitude determination as to whether the first provisional longitude FLN is appropriate as the longitude of the other device, based on the own device longitude LN _S and the first provisional longitude FLN. When determining the first longitude, the information processing unit 130 calculates the first longitude distance between the longitude _LNS of the own device and the first provisional longitude FLN at the latitude LT _S of the own device. Then, the information processing unit 130 determines whether the first provisional longitude FLN is appropriate as the longitude of another device by determining whether the calculated first longitude distance is less than or equal to the maximum reachable distance _DMAX . Perform a first longitude determination.

If the result of the determination in step S32 is positive (step S32: Y), the process proceeds to step S33. In this step S33, the information processing unit 130 specifies the first provisional longitude FLN as the longitude of the other device.

Once the longitude of the other device is specified in this way, the process of step S14 ends. The process then proceeds to step S11 in FIG.

If the result of the determination in step S32 described above is negative (step S32: N), the process proceeds to step S34. In this step S34, the information processing unit 130 calculates the second provisional longitude (second provisional transmitting side longitude) SLN using the following equation (5).
SLN=(LNU _S +0.1)+LNL _T ...(5)

In addition, if the second provisional longitude SLN exceeds 180 degrees, if the own device's longitude LN _S is the east longitude, it will be changed to the west longitude, and if the own device's longitude LN _S is the west longitude, it will be changed to the east longitude. At the same time, the numerical part is set to (180-LNL _T ), and the second provisional longitude SLN is set.

Subsequently, in step S35, the information processing unit 130 performs a second longitude determination as to whether or not the second provisional longitude SLN is appropriate as the longitude of the other device, based on the own device longitude LN _S and the second provisional longitude SLN. When determining the second longitude, the information processing unit 130 calculates a second longitude distance between the longitude _LNS of the own device and the second provisional longitude SLN at the latitude LT _S of the own device. Then, the information processing unit 130 determines whether the second provisional longitude SLN is appropriate as the longitude of another device by determining whether the calculated distance between the second longitudes is less than or equal to the maximum reachable distance _DMAX . Perform a second longitude determination.

If the result of the determination in step S35 is affirmative (step S35: Y), the process proceeds to step S36. In step S36, the information processing unit 130 specifies the second provisional longitude SLN as the longitude of the other device.

Once the longitude of the other device is specified in this way, the process of step S14 ends. The process then proceeds to step S11 in FIG.

If the result of the determination in step S35 described above is negative (step S35: N), the process proceeds to step S37. In this step S37, the information processing unit 130 calculates the third provisional longitude (third provisional transmitting side longitude) TLN using the following equation (6).
TLN=(LNU _S -0.1)+LNL _T ...(6)

In addition, if the third provisional longitude TLN becomes a negative value, if the own device's longitude LN _S is the east longitude, it will be changed to the west longitude, and if the own device's longitude LN _S is the west longitude, it will be changed to the east longitude. At the same time, the numerical part is set to (0.1-LNL _T ), and the third provisional longitude TLN is set.

Next, in step S38, the information processing unit 130 specifies the third provisional longitude TLN as the longitude of another device. Once the longitude of the other device is specified in this way, the process of step S14 ends. The process then proceeds to step S11 in FIG.

Note that FIG. 7 schematically shows the procedure for calculating the first to third provisional longitudes described above.

As explained above, in this embodiment, between devices that perform wireless LAN communication according to the WiFi standard, the second decimal place to the sixth decimal place of the position detection result (latitude and longitude) in decimal notation of each device is calculated. Exchange as location information (latitude information and longitude information). Here, the reason why the most significant digit of the location information to be exchanged is set to the second decimal place is determined in consideration of the longest reachable distance of a wireless signal in the WiFi standard. Furthermore, the reason why the lowest digit of the position information to be exchanged is set to the 6th decimal place is determined in response to the fact that the position identification accuracy at about 10 [cm] is the desired identification accuracy.

When the location information of another device is received through the operation of exchanging location information, the information processing unit 130 in the wireless LAN communication device 100 of this embodiment processes the received latitude information and longitude information and the information provided in the wireless LAN communication device 100. Based on the position detection result by the position detection unit 120, the position of the other device that transmitted the received position information is specified.

Therefore, the location of the other device (the latitude and longitude of the other device) can be specified with sufficient accuracy through efficient communication that reduces the amount of communication used to exchange location information.

Furthermore, in the wireless LAN communication device 100 of the present embodiment, when specifying the latitude of another device, the information processing unit 130 obtains the information by combining the part of the latitude of the own device above the first decimal place with the latitude information in the received position information. A first provisional latitude is calculated. If the first inter-latitude distance between the own device's latitude and the first provisional latitude at the same longitude is less than or equal to the maximum reachable distance, the information processing unit 130 uses the first provisional latitude as the other device's latitude. Identify. On the other hand, if the distance between the first latitudes is longer than the maximum reachable distance, the second provisional latitude is calculated by adding 0.1 degree to the first provisional latitude, and the second provisional latitude is calculated by adding 0.1 degree to the first provisional latitude. Of the subtracted third provisional latitudes, the information processing unit 130 selects the ones that are less than or equal to the longest reachable distance among the second and third latitude distances, which are the distances between the latitudes of the device itself at the same longitude. Specify as other device latitude.

Furthermore, in the wireless LAN communication device 100 of the present embodiment, when specifying the longitude of another device, the information processing unit 130 obtains the longitude by combining the part of the longitude of the own device above the first decimal place with the longitude information in the received position information. A first provisional longitude is calculated. If the first longitude distance between the longitude of the own device and the first provisional longitude at the latitude of the own device is less than or equal to the maximum reachable distance, the first provisional longitude is specified as the longitude of the other device. On the other hand, if the distance between longitudes is longer than the longest reachable distance, the second provisional longitude is obtained by adding 0.1 degree to the first provisional longitude, and the second provisional longitude is obtained by subtracting 0.1 degree from the first provisional longitude. Among the third provisional longitudes, a longitude that is less than or equal to the longest reachable distance among the second and third longitude distances, which are distances between the longitude of the own device and the latitude of the own device, is specified as the longitude of the other device.

Therefore, the location of another device can be specified easily and rationally.

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

For example, in the above embodiment, the WiFi standard is adopted as the standard for wireless communication between devices, but the present invention can also be applied when other short-range wireless communication standards are adopted.

Further, in the above embodiment, the position detection results in each device are displayed in decimal format, but the display may be in other formats.

Further, in the above embodiment, the wireless LAN communication device is placed in a vehicle, but it may be placed in a moving object other than a vehicle.

Furthermore, in the above embodiment, GPS positioning is also performed in the access point device. On the other hand, the fixed installation position of the access point device may be measured in advance, and the measurement results may be stored in a storage device included in the access point device.

Further, in the above embodiment, the distance between latitudes and the distance between longitudes is calculated according to the Lambert-Andoyer formula, but the distance between latitudes and the distance between longitudes is calculated according to a formula other than the Lambert-Andoyer formula such as Ono's formula. The distance may also be calculated.

Furthermore, in the above embodiment, the maximum reachable distance is twice the maximum wireless communication distance in the short-range wireless standards adopted by each country. On the other hand, the maximum reachable distance may be determined through experiments or the like.

Further, in the above embodiment, if the first provisional latitude and the second provisional latitude are inappropriate, the third provisional latitude is unconditionally specified as the latitude of another device, and the first provisional longitude and second provisional longitude are If it is not appropriate, the third provisional longitude is unconditionally specified as the longitude of another device. On the other hand, the appropriateness of the third provisional latitude and third provisional longitude may also be determined, and if they are not appropriate, error processing may be performed and the occurrence of an error may be presented to the user.

Note that the information processing unit in the above embodiment is configured as a computer as a calculation unit equipped with a central processing unit (CPU), etc., and information is processed by executing a program prepared in advance on the computer. 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. Further, this program may be obtained in the form recorded on a portable recording medium such as a CD-ROM or DVD, or may be obtained in the form of distribution via a network such as the Internet. Good too.

100...Wireless LAN communication device (receiving device, own device)
110... Wireless transmitter/receiver (receiver)
120...Position detection unit (receiving side position detection unit)
130... Information processing section (specific section)
200 ₁ to 200 _N … Wireless LAN communication device (other device)
300...Access point device (other device)

Claims (8)

Latitude and longitude information indicating the current location of another device, expressed in decimal notation and determined according to the maximum reachable distance corresponding to the wireless communication method adopted for wireless communication with the other device. Information for a predetermined number of digits from the first digit to the second digit lower than the first digit, which is determined according to the specific accuracy to be achieved for the latitude information and longitude information where the other device is located. a receiving unit that receives certain transmitter position information;
A receiving side that includes latitude and longitude information of its own device, which is capable of specifying the location of said device on the earth, and includes information from the most significant digit to the second digit when expressed in decimal notation. a receiving side position detection unit that detects position information;
After calculating provisional transmission position information based on the transmission side position information and the reception side position information, the distance between latitude and longitude between the position indicated by the reception side position information and the position indicated by the provisional transmission position information. an identification unit that calculates the distance of and identifies the latitude and longitude of the other device based on the calculated distance and the longest reachable distance;
The first digit is the longest distance between latitudes at the same longitude when the value of the digit one digit above the first digit differs by "1" and the values of the other digits are the same. It is set to be longer than the possible distance,
In the second digit, if the value of the second digit differs by "1" and the values of the other digits are the same, then both the distance between latitudes at the same longitude and the distance between longitudes at the same latitude are The distance is set to be less than or equal to the specific accuracy level,
The specific part is
Compare the latitude and longitude distances between the location indicated by the receiving side location information and the location indicated by the provisional transmission location information with the longest reachable distance, and determine whether the provisional location information is appropriate. Determine whether or not
When the provisional location information is appropriate, specifying the latitude and longitude of the provisional transmission location information as the latitude and longitude of the other device;
The provisional transmission position information includes a latitude upper digit part that is a higher digit than the first digit in the decimal representation of the latitude information of the receiving side position information, and a latitude in the decimal representation of the sending side position information. a first provisional sender latitude obtained by combining the information;
The specific part is
If the distance between the first latitudes at the same longitude between the receiving side latitude determined from the latitude information of the receiving side position information and the first provisional sending side latitude is shorter than the maximum reachable distance, the first provisional transmission specifying the side latitude to the latitude of the other device ;
If the distance between latitudes at the same longitude between the receiving side latitude determined from the latitude information of the receiving side position information and the first provisional transmitting side latitude is longer than the maximum reachable distance, the lowest digit of the upper digit part of the latitude A latitude correction value in which one digit is set to "1" and the other digits are set to "0" is added to the first provisional sender latitude to calculate a second provisional sender latitude, and the receiver calculates the second provisional sender latitude in the case of the same longitude. when the second inter-latitude distance between the side latitude and the second provisional sending side latitude is shorter than the maximum reachable distance, specifying the second provisional sending side latitude as the latitude of the other device;
If the distance between the second latitudes is longer than the maximum reachable distance, subtract the latitude correction value from the first provisional sender latitude to calculate the third provisional sender latitude, and calculate the third provisional sender latitude in the case of the same longitude. When a third inter-latitude distance between the receiving side latitude and the third provisional sending side latitude is shorter than the maximum reachable distance, specifying the third provisional sending side latitude as the latitude of the other device;
A receiving device characterized by: Latitude and longitude information indicating the current location of another device, expressed in decimal notation and determined according to the maximum reachable distance corresponding to the wireless communication method adopted for wireless communication with the other device. Information for a predetermined number of digits from the first digit to the second digit lower than the first digit, which is determined according to the specific accuracy to be achieved for the latitude information and longitude information where the other device is located. a receiving unit that receives certain transmitter position information;
A receiving side that includes latitude and longitude information of its own device, which is capable of specifying the location of said device on the earth, and includes information from the most significant digit to the second digit when expressed in decimal notation. a receiving side position detection unit that detects position information;
After calculating provisional transmission position information based on the transmission side position information and the reception side position information, the distance between latitude and longitude between the position indicated by the reception side position information and the position indicated by the provisional transmission position information. an identification unit that calculates the distance of and identifies the latitude and longitude of the other device based on the calculated distance and the longest reachable distance;
The first digit is the longest distance between latitudes at the same longitude when the value of the digit one digit above the first digit differs by "1" and the values of the other digits are the same. It is set to be longer than the possible distance,
In the second digit, if the value of the second digit differs by "1" and the values of the other digits are the same, then both the distance between latitudes at the same longitude and the distance between longitudes at the same latitude are The distance is set to be less than or equal to the specific accuracy level,
The specific part is
Compare the latitude and longitude distances between the location indicated by the receiving side location information and the location indicated by the provisional transmission location information with the longest reachable distance, and determine whether the provisional location information is appropriate. Determine whether or not
When the provisional location information is appropriate, specifying the latitude and longitude of the provisional transmission location information as the latitude and longitude of the other device;
The provisional transmission position information includes a longitude upper digit part that is a digit higher than the first digit in the decimal representation of the longitude information of the receiving side position information, and a longitude in the decimal representation of the transmitting side position information. a first provisional sender longitude obtained by combining the information;
The specific part is
The first longitude distance between the receiving side longitude determined from the longitude information of the receiving side position information and the first provisional transmitting side longitude at the receiving side latitude determined from the latitude information of the receiving side position information is longer than the reachable longest distance. If it is shorter, specifying the first provisional transmitting side longitude as the longitude of the other device,
If the distance between the receiving side longitude determined from the longitude information of the receiving side position information and the first provisional transmitting side longitude at the receiving side latitude is longer than the maximum reachable distance, the upper digit part of the longitude A longitude correction value in which the least significant digit is set to "1" and the other digits are set to "0" is added to the first provisional sending side longitude to calculate the second provisional sending side longitude, and the second provisional sending side longitude is calculated. When the second longitude distance between the receiving side longitude and the second provisional sending side longitude is shorter than the longest reachable distance, specifying the second provisional sending side longitude as the longitude of the other device;
If the distance between the second longitudes is longer than the maximum reachable distance, the longitude correction value is subtracted from the first provisional sender longitude to calculate a third provisional sender longitude, and the longitude at the receiver latitude is calculated. When the third longitude distance between the receiving side longitude and the third provisional sending side longitude is shorter than the maximum reachable distance, specifying the third provisional sending side longitude to the latitude of the other device;
A receiving device characterized by: the first digit is the second decimal place;
the second digit is the sixth decimal place;
The receiving device according to claim 1 or 2, characterized in that: The receiving unit receives the transmitting side position information converted into 94-decimal notation,
The specifying unit specifies the latitude and longitude of the other device after converting the transmitting side position information converted into the 94-decimal notation into a decimal notation.
The receiving device according to any one of claims 1 to 3, characterized in that: Latitude and longitude information indicating the current location of another device, expressed in decimal notation and determined according to the maximum reachable distance corresponding to the wireless communication method adopted for wireless communication with the other device. Receive transmitter position information, which is information for a predetermined number of digits from the first digit to the second digit lower than the first digit, which should be realized regarding the latitude information and longitude information where the other device is located. a receiving unit that receives latitude information and longitude information of its own device, which is capable of specifying the position of said device on the earth, and which is expressed in decimal notation from the most significant digit to the second digit; A receiving side position detection unit that detects receiving side position information including information; a position specifying method used in a receiving device, comprising:
an acquisition step of acquiring the transmitting side position information received by the receiving section and the receiving side position information detected by the receiving side position detecting section;
After the specifying unit calculates provisional transmission position information based on the transmission side position information and the reception side position information, the latitude difference between the position indicated by the reception side position information and the position indicated by the provisional transmission position information is determined. and determining the latitude and longitude of the other device based on the calculated distance and the longest reachable distance;
The first digit is the longest distance between latitudes at the same longitude when the value of the digit one digit above the first digit differs by "1" and the values of the other digits are the same. It is set to be longer than the possible distance,
In the second digit, if the value of the second digit differs by "1" and the values of the other digits are the same, then both the distance between latitudes at the same longitude and the distance between longitudes at the same latitude are The distance is set to be less than or equal to the specific accuracy level,
The specific step is
The specifying unit compares the distance between latitudes and longitudes between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information with the longest possible reachable distance, and determines the provisional position information. A determination step for determining whether or not is appropriate:
a latitude and longitude identifying step of identifying the latitude and longitude of the provisional transmission location information as the latitude and longitude of the other device when the provisional location information is appropriate;
The provisional transmission position information includes a latitude upper digit part that is a higher digit than the first digit in the decimal representation of the latitude information of the receiving side position information, and a latitude in the decimal representation of the sending side position information. a first provisional sender latitude obtained by combining the information;
The latitude and longitude specifying step includes:
If the distance between the first latitudes at the same longitude between the receiving side latitude determined from the latitude information of the receiving side position information and the first provisional transmitting side latitude is shorter than the longest reachable distance, the identifying unit: a first latitude specifying step of specifying the first provisional sending side latitude to the latitude of the other device;
If the distance between latitudes at the same longitude between the receiving side latitude determined from the latitude information of the receiving side position information and the first provisional transmitting side latitude is longer than the maximum reachable distance, the lowest digit of the upper digit part of the latitude A latitude correction value in which one digit is set to "1" and the other digits are set to "0" is added to the first provisional sender latitude to calculate a second provisional sender latitude, and the receiver calculates the second provisional sender latitude in the case of the same longitude. a second latitude that specifies the second provisional sender latitude as the latitude of the other device when a second inter-latitude distance between the side latitude and the second provisional sender latitude is shorter than the longest reachable distance; Specific process;
If the distance between the second latitudes is longer than the maximum reachable distance, subtract the latitude correction value from the first provisional sender latitude to calculate the third provisional sender latitude, and calculate the third provisional sender latitude in the case of the same longitude. when the third inter-latitude distance between the receiving side latitude and the third provisional sending side latitude is shorter than the maximum reachable distance, specifying the third provisional sending side latitude to the latitude of the other device; 3 latitude identification step;
A location identification method characterized by: A location specifying program that causes a computer included in a receiving device to execute the location specifying method according to claim 5 . Latitude and longitude information indicating the current location of another device, expressed in decimal notation and determined according to the maximum reachable distance corresponding to the wireless communication method adopted for wireless communication with the other device. Receive transmitter position information, which is information for a predetermined number of digits from the first digit to the second digit lower than the first digit, which should be realized regarding the latitude information and longitude information where the other device is located. a receiving unit that receives latitude information and longitude information of its own device, which is capable of specifying the position of said device on the earth, and which is expressed in decimal notation from the most significant digit to the second digit; A receiving side position detection unit that detects receiving side position information including information; a position specifying method used in a receiving device, comprising:
an acquisition step of acquiring the transmitting side position information received by the receiving section and the receiving side position information detected by the receiving side position detecting section;
After the specifying unit calculates provisional transmission position information based on the transmission side position information and the reception side position information, the latitude difference between the position indicated by the reception side position information and the position indicated by the provisional transmission position information is determined. and determining the latitude and longitude of the other device based on the calculated distance and the longest reachable distance;
The first digit is the longest distance between latitudes at the same longitude when the value of the digit one digit above the first digit differs by "1" and the values of the other digits are the same. It is set to be longer than the possible distance,
In the second digit, if the value of the second digit differs by "1" and the values of the other digits are the same, then both the distance between latitudes at the same longitude and the distance between longitudes at the same latitude are The distance is set to be less than or equal to the specific accuracy level,
In the identifying step, the identifying unit compares the distance between latitudes and longitudes between the position indicated by the receiving side position information and the position indicated by the provisional transmission position information, and the longest reachable distance. , a determination step of determining whether the provisional location information is appropriate: when the provisional location information is appropriate, identifying the latitude and longitude of the provisional transmission location information as the latitude and longitude of the other device; a latitude and longitude identification step;
The provisional transmission position information includes a latitude upper digit part that is a higher digit than the first digit in the decimal representation of the latitude information of the receiving side position information, and a latitude in the decimal representation of the sending side position information. a first provisional sender latitude obtained by combining the information;
The latitude and longitude specifying step includes:
The first longitude distance between the receiving side longitude determined from the longitude information of the receiving side position information and the first provisional transmitting side longitude at the receiving side latitude determined from the latitude information of the receiving side position information is longer than the reachable longest distance. a first longitude specifying step in which, if the longitude is short, the specifying unit specifies the first provisional transmitting side longitude to the longitude of the other device;
If the distance between the receiving side longitude determined from the longitude information of the receiving side position information and the first provisional transmitting side longitude at the receiving side latitude is longer than the maximum reachable distance, the upper digit part of the longitude A longitude correction value in which the least significant digit is set to "1" and the other digits are set to "0" is added to the first provisional sending side longitude to calculate the second provisional sending side longitude, and the second provisional sending side longitude is calculated. When the second longitude distance between the receiving side longitude and the second provisional sending side longitude is shorter than the maximum reachable distance, specifying the second provisional sending side longitude to the longitude of the other device. 2 longitude identification process;
If the distance between the second longitudes is longer than the maximum reachable distance, the specifying unit subtracts the longitude correction value from the first provisional sender longitude to calculate a third provisional sender longitude, and When the third longitude distance between the receiving side longitude and the third provisional sending side longitude at the receiving side latitude is shorter than the maximum reachable distance, the third provisional sending side longitude is set to the latitude of the other device. A position specifying method comprising: a third longitude specifying step; A location specifying program that causes a computer included in a receiving device to execute the location specifying method according to claim 7.