JP2009092594A - Position estimation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position estimation system capable of accurately estimating the position of a radiocommunication terminal (a radio device) in a location where the own positional information in a building or the like is difficult to detect. <P>SOLUTION: Each of a plurality of radio devices communicating with one another by ad hoc type radiocommunication includes a GPS 20 generating positional information on the position of the own radio device and generating position unknown information when the position of the own radio device is unknown; a CPU 18 generating transmitting/receiving information based on information on a transmitting electric power value when transmitting information to the other radio device, information on the other radio device that transmitted information to the own radio device, and information on a receiving electric power value when receiving information from the other radio device; and a transmitting/receiving part 16 transmitting/receiving the positional information, position unknown information and transmitting/receiving information by radiocommunication. At least one of the plurality of radio devices includes a position estimating part for estimating the position of the radio device that transmitted the position unknown information, based on the positional information and transmitting/receiving information received by the transmitting/receiving part 16. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is composed of a plurality of wireless communication terminals capable of detecting their own position information based on GPS or the like, and is capable of estimating the position of a wireless communication terminal in a place where it is difficult to detect its own position information such as in a building. About the system.

  Conventionally, a positioning system such as GPS (Global Positioning System) has been used to identify the current position of the user. When using GPS, a user receives radio waves of three or more GPS satellites with a GPS receiver and calculates a relative distance difference between each satellite, thereby enabling two-dimensional or three-dimensional positioning. It becomes possible.

  However, indoors where it is impossible to receive GPS satellite radio waves, it is difficult for a user to obtain his / her position information even if he / she carries a GPS receiver. Also, a user who is outdoors cannot specify or estimate the position of a wireless communication terminal having a GPS receiver that is indoors.

  Patent Document 1 describes an indoor position detection apparatus and an indoor position detection method that can detect the movement direction and movement distance of a worker with high accuracy even in a large indoor space and can accurately grasp the current position of the worker. This indoor position detection method receives a reference position signal at an indoor reference position, obtains a relative position from the reference position by detecting the travel distance and travel direction from the reference position, and calculates the absolute position from the relative position with respect to the reference position. Is detected by correcting the relative azimuth detected by the relative azimuth detecting means using the absolute azimuth detected by the absolute azimuth detecting means.

  Therefore, according to the indoor position detection device described in Patent Document 1, even when GPS satellite radio waves cannot be received indoors, an indoor absolute position can be detected based on the relative position from the detected reference position. .

  Further, Patent Document 2 describes a portable terminal and a location information exchange system that can estimate a self-location without using a communication fee even when the GPS function is not provided or in an environment where the GPS function cannot be used. Has been.

  The self-position estimation means possessed by this mobile terminal receives position accuracy information indicating the accuracy of the position information along with the position information from nearby mobile terminals by the short-range wireless communication means, The accuracy is also estimated.

In other words, this mobile terminal obtains position information and position accuracy information from a plurality of nearby mobile terminals by wireless communication, and by setting that the sizes of the short-range communication range of all mobile terminals are equal, The position of self can be estimated.
JP 2004-138513 A JP 2005-223436 A

  However, in the indoor position detection device and the indoor position detection method described in Patent Document 1, when the relative position from the reference position is obtained, the travel distance is obtained by calculating the number of steps and the step length using a biaxial acceleration sensor. Since there are individual differences with respect to the stride, it is difficult to say that precise measurement is possible under any conditions.

  In addition, since the position information exchange system described in Patent Document 2 estimates the self-position with the short-range wireless communication range of all portable terminals being the same, the range in which the communicable ranges of communicable portable terminals overlap is wide. In some cases, the estimated self-location is also inaccurate. In addition, each mobile terminal cannot use information on a mobile terminal that cannot directly communicate with its own mobile terminal when estimating its own position for estimating its own position.

  The present invention solves the above-mentioned problems of the prior art, and is composed of a plurality of wireless communication terminals capable of detecting own position information based on GPS or the like, and is difficult to detect its own position information such as in a building. It is an object of the present invention to provide a position estimation system capable of accurately estimating the position of a wireless communication terminal.

  In order to solve the above problems, a position estimation system according to the present invention is a position estimation system including a plurality of communication terminals that communicate with each other by ad hoc wireless communication, and each of the plurality of communication terminals includes: Generates position information related to the position of its own communication terminal, and transmits information to other communication terminals, and a position information generation unit that generates position unknown information when the position of its own communication terminal is unknown Transmission / reception information is generated based on information on the transmission power value at the time, information on other communication terminals that transmitted information to the own communication terminal, and information on the received power value when information is received from other communication terminals A transmission / reception information generation unit, position information generated by the position information generation unit, position unknown information, and transmission / reception information generated by the transmission / reception information generation unit are wirelessly transmitted. And at least one of the plurality of communication terminals transmits the position unknown information based on the position information and the transmission / reception information of the other communication terminals received by the transmission / reception unit. A position estimation unit for estimating the position of the communication terminal is provided.

  According to the present invention, it is possible to effectively use information held by a plurality of wireless communication terminals constituting the position estimation system, and to perform accurate position estimation of a wireless communication terminal in a place where it is difficult to detect its own position information such as in a building. It can be carried out.

  Hereinafter, embodiments of the position estimation system of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of a wireless device 3 that is a communication terminal constituting the position estimation system according to the first embodiment of the present invention. The position estimation system includes a plurality of communication terminals that communicate with each other by ad hoc wireless communication. That is, the position estimation system constitutes an ad hoc network by a plurality of communication terminals (wireless devices 3) shown in FIG. FIG. 2 is a diagram illustrating an example of position estimation using a plurality of communication terminals illustrated in FIG. 1 in the position estimation system according to the first embodiment of the present invention. Each wireless device corresponds to the communication terminal of the present invention.

  Here, the ad hoc network is a network composed of mobile terminals having an exchange function that does not depend on an exchange or a base station. In an ad hoc network, terminal devices communicate with each other on an equal basis. A route in an ad hoc network is generally determined by a routing protocol. The ad hoc routing protocol is a communication protocol that forms a network between a plurality of terminals in a wireless environment, and realizes construction of a route by transmitting and receiving search packets.

  Routing protocols are roughly classified into two types, a proactive type and a reactive type, in route discovery processing. The proactive type is a method of confirming and grasping the surrounding network state in advance prior to communication, and one example is OLSR (Optimized Link State Routing). According to the OLSR protocol, a node having a large number of peripheral nodes to which radio waves reach directly becomes a relay node on behalf of the neighboring nodes, so that unnecessary relay flooding is suppressed, so that flooding is efficiently performed. There is a feature that can be. The reactive type is a method in which a route discovery process is performed only when a request for a certain node to communicate with another node is triggered.

  The position estimation system according to the first embodiment of the present invention can be realized by any method. First, the configuration of the present embodiment will be described. As shown in FIG. 1, the wireless device 3 used in the position estimation system of this embodiment includes a GPS receiving antenna 12, a wireless communication antenna 14, a transmission / reception unit 16, a CPU 18, and a GPS 20. Note that the wireless device 2, the wireless device 4, the wireless device 5, and the wireless device 6 that constitute the position estimation system of the present embodiment illustrated in FIG. 2 all have the same configuration as the wireless device 3.

  The GPS receiving antenna 12 is an antenna that receives radio waves from the GPS satellite 10 shown in FIG. 2 and is connected to the transmission / reception unit 16. The wireless communication antenna 14 is an antenna such as a monopole antenna normally used in a portable information terminal device, for example, and is connected to the transmission / reception unit 16. Whereas the radio communication antenna 14 is used for both transmitting and receiving information, the GPS receiving antenna 12 only receives radio waves from the GPS satellite 10.

  The transmission / reception unit 16 receives radio waves of the GPS satellite 10 via the GPS reception antenna 12 and transmits / receives information such as search packets and communication data via the wireless communication antenna 14 by wireless communication. Further, in this embodiment, the transmission / reception unit 16 transmits / receives the position information and the position unknown information generated by the GPS 20 via the wireless communication antenna 14 by wireless communication, and transmits / receives the transmission / reception information generated by the CPU 18 by wireless communication. Transmission / reception is performed via the wireless communication antenna 14. The position information, position unknown information, and transmission / reception information will be described later.

  The GPS 20 corresponds to the position information generation unit of the present invention, generates position information regarding the position of its own communication terminal (here, the wireless device 3), and the position of its own communication terminal (wireless device 3) is unknown. In this case, position unknown information is generated. In this embodiment, the GPS 20 receives the radio wave of the GPS satellite 10 received by the transmitting / receiving unit 16 via the GPS receiving antenna 12 via the CPU 18, calculates the relative distance difference from the GPS satellite 10, and calculates its own distance. Obtain location information (eg latitude and longitude). That is, the GPS 20 detects the position of its own communication terminal using GPS (Global Positioning System) and generates position information. As a matter of course, there are actually a plurality of GPS satellites, but a description thereof is omitted here.

  If the wireless device 3 is in an environment where it cannot receive radio waves from the GPS satellites 10 such as in a building, the GPS 20 cannot acquire its own location information, and thus the location unknown information indicating that its own location is unknown. Is generated.

  The CPU 18 corresponds to the transmission / reception information generation unit of the present invention, and information on the transmission power value when transmitting information to other communication terminals (radio devices), other information transmitted to the own communication terminal Transmission / reception information is generated based on information on a communication terminal (wireless device) and information on a received power value when information is received from another communication terminal (wireless device).

  In addition, the CPU 18 collects various information necessary for constructing an ad hoc network and performing path control, and controls transmission of search packets and communication data for collecting information on other wireless devices. Further, in order to construct an ad hoc network, the CPU 18 may have an algorithm for collecting information on other communication terminals to grasp the topology (connection form) of the entire network and controlling the communication path of the ad hoc network.

  Next, the structure of the position estimation system in a present Example is demonstrated using FIG. First, as described above, the wireless device 2, the wireless device 3, the wireless device 4, the wireless device 5, and the wireless device 6 have the same internal configuration. However, since the radio device 6 possessed by the worker 7 is in the building, it cannot receive radio waves from the GPS satellite 10. Other wireless device 2, wireless device 3, wireless device 4, and wireless device 5 are installed outdoors and can receive radio waves from GPS satellite 10.

  A circle with a broken line drawn around the wireless device 3, the wireless device 4, and the wireless device 5 indicates the wireless communicable range of each wireless device. Therefore, the wireless device 3, the wireless device 4, and the wireless device 6 can directly communicate with each other, but the wireless device 5 and the wireless device 6 cannot directly communicate with each other.

  In view of the wireless communication range shown in FIG. 2, the wireless device 4 and the wireless device 5 cannot directly communicate with each other, and the wireless device 2 and the wireless device 3 cannot directly communicate with each other. Therefore, although it seems that the wireless device 2 and the wireless device 5 are independent, the wireless device 2 can actually communicate by relaying a wireless device not shown. Accordingly, the wireless device 2, the wireless device 3, the wireless device 4, the wireless device 5, and the wireless device 6 form an ad hoc network and can share information by transmitting and receiving information to and from each other.

  The wireless device 2 is connected to the terminal 1 by, for example, a wired LAN. The terminal 1 corresponds to the position estimation unit of the present invention, and the position of the wireless device that transmitted the position-unknown information based on the position information and the transmission / reception information of another wireless device received by the transmitting / receiving unit 16 in the wireless device 2 Is estimated.

  In FIG. 2, the terminal 1 is externally connected to the wireless device 2, but a configuration in which a position estimation unit is built in the wireless device 2 may be employed. Further, in the present embodiment, the communication terminal having the terminal 1 that is the position estimation unit is only the wireless device 2, but when implementing the present invention, the number of wireless devices including the position estimation unit is not limited to one. But you can. At least one of the plurality of wireless devices constituting the position estimation system includes a position estimation unit.

  The terminal 1 that is a position estimation unit estimates the distance between the wireless devices from the received power value and the transmission power value in each wireless device based on the transmission / reception information, thereby determining the position of the wireless device that transmitted the position unknown information. presume.

  In addition, the terminal 1 estimates the communicable range of each wireless device based on the transmission power value of each wireless device included in the transmission / reception information, and can directly communicate the position of the wireless device that transmitted the position unknown information. The position of the wireless device that has transmitted the position unknown information is estimated using the fact that it is outside the communicable range of the wireless device that cannot.

  In the present embodiment, the terminal 1 has a position display device. This position display device corresponds to the display unit of the present invention, and displays the positional relationship of each wireless device based on the position information of each wireless device and the position estimated by the position estimating unit. Therefore, it can be said that the wireless device 2 includes a position display device.

  Next, the operation of the present embodiment configured as described above will be described. The wireless device 2 and the terminal 1 are used by an administrator (not shown). In the present embodiment, it is assumed that the worker 7 wearing the wireless device 6 performs work indoors such as a building.

  When limited to the wireless device 3, the GPS 20 in the wireless device 3 generates position information (latitude and longitude) related to the position of the wireless device 3 based on the radio wave of the GPS satellite 10 and transmits / receives it via the CPU 18. To the unit 16.

  In addition, the CPU 18 in the wireless device 3 includes information on a transmission power value when transmitting information to other communication terminals, information on other wireless devices that have transmitted information to the wireless device 3, and other information. Transmission / reception information is generated based on the information about the received power value when the information is received from the wireless device, and is output to the transmission / reception unit 16.

  Here, the wireless devices that can transmit information to the wireless device 3 are the wireless device 4, the wireless device 6, and other wireless devices not shown. Here, it is assumed that only the wireless device 4 and the wireless device 6 transmit information to the wireless device 3. In that case, the CPU 18 in the wireless device 3 transmits information on the transmission power value when transmitting information to other wireless devices, and the wireless device 4 and the wireless device 6 transmit information to the wireless device 3 of itself. The transmission / reception information is generated based on the information on the received power and the information on the received power value for each wireless device when the information is received from the wireless device 4 and the wireless device 6.

  The transmission / reception unit 16 transmits the position information and the transmission / reception information at a predetermined timing based on the protocol by wireless communication to another wireless device capable of transmitting the position information and the transmission / reception information. In addition, the transmission / reception unit 16 receives the position information and the transmission / reception information transmitted by other wireless devices by wireless communication.

  Similarly, when limited to the radio device 6, the GPS 20 in the radio device 6 cannot receive the radio wave of the GPS satellite 10 and the position of the own radio device 6 is unknown. The data is output to the transmission / reception unit 16 via the CPU 18.

  Further, the wireless devices that can transmit information to the wireless device 6 are the wireless device 3, the wireless device 4, and other wireless devices not shown. Here, it is assumed that only the wireless device 3 and the wireless device 4 transmit information to the wireless device 6. In that case, the CPU 18 in the wireless device 6 transmits information on the transmission power value when transmitting information to other wireless devices, and the wireless device 3 and the wireless device 4 transmit information to the wireless device 6 of itself. Transmission / reception information is generated based on the information indicating that the transmission has been performed, and information regarding the received power value for each wireless device when the information is received from the wireless device 3 and the wireless device 4, and is output to the transmitting / receiving unit 16.

  The operation of the transmission / reception unit 16 in the wireless device 6 is the same as the operation of the transmission / reception unit 16 in the wireless device 3.

  Similarly, the wireless device 2, the wireless device 4, the wireless device 5, and other wireless devices (not shown) forming an ad hoc network also transmit / receive position information or position unknown information and transmission / reception information to / from each other and share information.

  The terminal 1 connected to the wireless device 2 estimates the position of the wireless device 6 that transmitted the position unknown information based on the position information and the transmission / reception information of the other wireless device received by the transmitting / receiving unit 16 in the wireless device 2. To do.

  Specifically, the terminal 1 estimates the position of the wireless device 6 by estimating the distance between the wireless devices from the reception power value and the transmission power value in each wireless device based on the transmission / reception information. In the present embodiment, the “transmission power value of the wireless device 3” included in the transmission / reception information transmitted by the wireless device 3 and the “when information is received from the wireless device 3” included in the transmission / reception information transmitted by the wireless device 6. From the “reception power value with respect to the wireless device 3”, the terminal 1 calculates the attenuation amount of the radio wave intensity and estimates the distance between the wireless device 3 and the wireless device 6. Further, the terminal 1 estimates the distance between the wireless device 4 and the wireless device 6 by a similar method.

  Here, “the transmission power value of the wireless device 6” included in the transmission / reception information transmitted by the wireless device 6 and “the wireless device 6 when information is received from the wireless device 6” included in the transmission / reception information transmitted by the wireless device 3. The terminal 1 can also calculate the attenuation amount of the radio field intensity from the “received power value with respect to” and estimate the distance between the wireless device 3 and the wireless device 6. The same applies to the distance between the wireless device 4 and the wireless device 6.

  Further, since the transmission / reception information transmitted by the wireless device 6 does not include “information that the wireless device 5 has transmitted information to its own wireless device 6”, the terminal 1 transmits / receives the transmission / reception transmitted by the wireless device 5. The communication range of the wireless device 5 is estimated based on the “transmission power value of the wireless device 5” included in the information, and the position of the wireless device 6 is a communication terminal that cannot communicate directly. The position of the wireless device 6 is estimated using the fact that it is outside the possible range. Therefore, since the terminal 1 is a distance between the wireless device 3 and the wireless device 6, a distance between the wireless device 4 and the wireless device 6, and the wireless device 6 is outside the communicable range of the wireless device 5, The position of the wireless device 6 can be estimated.

  Further, since the transmission / reception information transmitted by the wireless device 6 does not include “information that the wireless device 2 has transmitted information to its own wireless device 6”, the terminal 1 transmits / receives the transmission / reception transmitted by the wireless device 2. The communication range of the wireless device 2 is estimated based on the “transmission power value of the wireless device 2” included in the information, and the position of the wireless device 6 is a communication terminal that cannot communicate directly. The position of the wireless device 6 can also be estimated using the fact that it is outside the possible range.

  Note that the terminal 1 estimates the position of the wireless device 6 based on the propagation loss distance characteristic in the indoor when performing wireless communication, assuming that the wireless device 6 that is the communication terminal that transmitted the position-unknown information exists indoors. You can also. This is because indoors, because of the presence of walls and the like, the intensity loss of radio waves used for wireless communication is large, and it is necessary to estimate the distance between the wireless devices shorter than usual. As an example, the indoor propagation loss distance characteristic (L) can be estimated by the following equation.

[Equation 1]
L = 20 · log ₁₀ f + N · log ₁₀ d + L _f (n) −28 (1)
Here, d is a distance [m] between transmission and reception points. N is an attenuation coefficient with respect to the distance between transmission and reception points. F is a frequency [MHz]. L _f is an additional loss due to passing through the floor, ceiling, and wall. n is the number of passing floors. N and L _f are parameters that depend on the propagation environment and the material of the building material.

  The wireless device 2 can also display the positional relationship of each wireless device on the position display device of the terminal 1. At that time, the position display device displays the positions of the wireless device 2, the wireless device 3, the wireless device 4, and the wireless device 5 on the map based on the position information transmitted by each wireless device, and is further estimated by the terminal 1. The position of the wireless device 6 can be displayed on the map.

  Here, the method for estimating the position of the communication terminal that has transmitted the position-unknown information will be described in detail with reference to FIG. First, it is assumed that there are a plurality of wireless devices (wireless device 22, wireless device 24, wireless device 26, and wireless device 28) having a positional relationship as shown in FIG. Since the wireless device 22, the wireless device 24, and the wireless device 26 have their own position information, each transmits its own position information. However, since the wireless device 18 does not have its own location information, it is assumed that the location unknown information is transmitted. Also, each wireless device forms an ad hoc network and shares information with each other. Here, since the circle 34 with a broken line indicates the communicable range of the radio device 26, the radio device 26 cannot directly communicate with the radio device 22 and the radio device 24, but is ad hoc via a radio device not shown. Assume that a network is formed.

  Assuming that the wireless device 22 has a position estimating unit, the position estimating unit of the wireless device 22 includes the “transmission power value of the wireless device 22” included in the transmission / reception information transmitted by the wireless device 22 itself, and the wireless device 18. It is estimated that the distance between the wireless device 18 and the wireless device 22 is d from the “reception power value for the wireless device 22 when information is received from the wireless device 22” included in the transmission / reception information transmitted by . Further, the position estimation unit of the wireless device 22 estimates that the distance between the wireless device 18 and the wireless device 24 is c by the same method.

  Therefore, the position estimation unit of the wireless device 22 estimates that the position of the wireless device 18 is on the circumference of the radius d centered on the wireless device 22, and the position of the wireless device 18 is centered on the wireless device 24. To be on the circumference of the radius c. That is, the position estimation unit of the wireless device 22 estimates that the position of the wireless device 18 is either the point a or the point b.

  When the wireless device 18 is present in the building, the position estimation unit of the wireless device 22 assumes that the wireless device 18 is present indoors and is based on the propagation loss distance characteristics in the indoor when performing wireless communication. The position of the wireless device 18 may be estimated. In that case, the position estimation unit of the radio device 22 estimates that the radii of the circle 30 and the circle 32 are even smaller.

  In addition, since the transmission / reception information transmitted by the wireless device 18 does not include “information that the wireless device 26 has transmitted information to its own wireless device 18”, the position estimation unit of the wireless device 22 26 estimates the communicable range (circle 34) of the wireless device 26 based on the “transmission power value of the wireless device 26” included in the transmission / reception information transmitted by the wireless device 26, and the position of the wireless device 18 cannot perform direct communication. The position of the wireless device 18 is estimated using the fact that it is outside the communicable range of the wireless device 26 that is the communication terminal (outside the circle 34). Therefore, since the point b is inside the circle 34, the position estimation unit of the wireless device 22 can estimate that the position of the wireless device 18 is the point a.

  Note that the position estimation method described above is an example, and more accurate position estimation is possible when there are more radios in the vicinity of the radio that transmitted the position-unknown information.

  In the present embodiment, each wireless device has the GPS 20 corresponding to the position information generation unit, but the GPS 20 is not necessarily required. If there is no GPS 20 in each wireless device, the CPU 18 in each wireless device corresponds to the position information generation unit of the present invention and also corresponds to the transmission / reception information generation unit. Since the position information cannot be acquired by GPS, the CPU of each wireless device has the position information of its own wireless device in advance or can acquire the position information of its own wireless device by external input or the like.

  For example, in FIG. 2, the wireless device 2, the wireless device 3, the wireless device 4, and the wireless device 5 have their own wireless device position information in advance and are installed at predetermined positions. Here, even when the wireless device 6 does not have the position information of its own wireless device, the terminal 1 obtains the position information generated by the CPU 18 in each wireless device or the position unknown information and the transmission / reception information, The position of the wireless device 6 can be estimated.

  In addition, as described above, when a radio having position information is arranged around a specific building in advance, the structure of the building is known, so the propagation loss distance characteristic in the indoor is calculated more accurately. There is an advantage that the position of the radio can be estimated accurately.

  As described above, according to the position estimation system according to the first embodiment of the present invention, by configuring an ad hoc network with a plurality of wireless devices capable of detecting own position information based on GPS or the like, Therefore, it is possible to accurately estimate the position of the radio in a place where it is difficult to detect the position information.

  In addition, the position estimation unit estimates the position of the wireless device that transmitted the position-unknown information by estimating the distance between the wireless devices from the reception power value and the transmission power value of each wireless device based on the transmission / reception information. Therefore, it is possible to accurately estimate the position as compared with the method in which the position is simply estimated from the place where the communicable ranges overlap.

  In addition, the position estimation unit uses an ad hoc network to transmit position information and transmission / reception information transmitted by a wireless device that cannot directly communicate with a wireless device that can directly communicate with a wireless device that is a target of position estimation. Since the position estimation is performed based on this, it is possible to estimate that the wireless apparatus is located outside the communicable range of the radio that cannot perform direct communication, which contributes to more accurate position estimation.

  Furthermore, the position estimation unit can perform position estimation based on the propagation loss distance characteristic in the indoor when performing wireless communication, assuming that the wireless device that transmitted the position unknown information is indoors. By assuming a propagation loss larger than usual, the position can be estimated accurately.

  Further, the position display device can display the positional relationship of each wireless device on a map based on the position information transmitted by each wireless device, and can further display the position of the wireless device estimated by the position estimating unit on the map. Therefore, it is possible to easily and clearly know the estimated position of the wireless device.

  The position estimation system according to the present invention confirms the position of the worker using GPS or wireless communication, and the position of the worker when the worker or the like works in a building where radio waves from the GPS satellite cannot be received. It can be used for a position estimation system for estimating.

It is a block diagram which shows the structure of the radio | wireless machine which comprises the position estimation system of the form of Example 1 of this invention. It is a figure which shows one example of the position estimation using a some radio | wireless machine in the position estimation system of the form of Example 1 of this invention. It is a figure explaining the estimation method of the position of the radio | wireless machine which transmitted the position unknown information in the position estimation system of the form of Example 1 of this invention.

Explanation of symbols

1 Terminal (position display device)
2, 3, 4, 5, 6 Radio device 7 Worker 10 GPS satellite 12 GPS receiving antenna 14 Wireless communication antenna 16 Transmission / reception unit 18 CPU
20 GPS
22, 24, 26, 28 Radio 30, 32, 34 yen

Claims (6)

A position estimation system composed of a plurality of communication terminals that communicate with each other by ad hoc wireless communication,
Each of the plurality of communication terminals is
A position information generating unit that generates position information related to the position of its own communication terminal and generates position unknown information when the position of its own communication terminal is unknown,
Information regarding the transmission power value when transmitting information to other communication terminals, information regarding other communication terminals that transmitted information to the own communication terminal, and reception when receiving information from other communication terminals A transmission / reception information generation unit that generates transmission / reception information based on information on the power value;
A transmission / reception unit that transmits / receives position information generated by the position information generation unit, position unknown information, and transmission / reception information generated by the transmission / reception information generation unit by wireless communication;
At least one of the plurality of communication terminals is
A position estimation system comprising: a position estimation unit that estimates a position of a communication terminal that has transmitted position unknown information based on the position information and the transmission / reception information of another communication terminal received by the transmission / reception unit.   The position estimation unit estimates the position of the communication terminal that transmitted the position-unknown information by estimating the distance between the communication terminals from the received power value and the transmission power value at each communication terminal based on the transmission / reception information. The position estimation system according to claim 1.   The position estimation unit estimates a communicable range of each communication terminal based on a transmission power value of each communication terminal included in the transmission / reception information, and directly communicates the position of the communication terminal that transmitted the position unknown information The position estimation system according to claim 1, wherein the position of the communication terminal that has transmitted the position-unknown information is estimated by using the fact that the communication terminal is out of a communicable range of the communication terminal that cannot perform communication.   The position estimation unit estimates the position of the communication terminal that transmitted the position unknown information based on the propagation loss distance characteristic in the indoor when performing wireless communication, assuming that the communication terminal that transmitted the position unknown information exists indoors. The position estimation system according to any one of claims 1 to 3, wherein:   The position information generation unit detects the position of its own communication terminal by using GPS (Global Positioning System), and generates position information. Position estimation system.   The communication terminal having the position estimation unit includes a display unit that displays a positional relationship of each communication terminal based on position information of each communication terminal and a position estimated by the position estimation unit. The position estimation system according to claim 5.

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