Terminal device and communication control method

Abstract

To suppress the occurrence of unnecessary communication.SOLUTION: A terminal device includes: a communication section for communicating with a target terminal device and a management device; a position detection section for detecting its own position information; a positioning request receiving section for receiving a positioning information request signal including a threshold of received radio wave intensity and the required number of responses from the target terminal device; a condition determination section for determining whether or not the received radio wave intensity in receiving the positioning information request signal is equal to or greater than the threshold; a time setting section for setting and measuring response waiting time according to the received radio wave intensity and priority information in receiving the positioning information request signal when the received radio wave intensity is equal to or greater than the threshold; a counting section for counting the number of responses to the positioning information request signal; a response number determination section for determining whether or not the number of responses reaches the required number of responses after the response waiting time has elapsed; and a positioning information transmission section for transmitting target positioning information including position information and the received radio wave intensity in receiving the positioning information request signal to the management device when the number of responses does not reach the required number of responses.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a terminal device and a communication control method. [Background technology]

[0002] There is known a technology that can determine one's own position using information from nearby terminals even if there is no positioning device or device fixedly installed at a known position in the vicinity (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-201921 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of the technology described in Patent Document 1, it is not possible to limit the number of terminals with which communication is possible when locating a target terminal device, which may increase communication traffic and result in unnecessary communication.

[0005] An object of the present invention is to provide a terminal device and a communication control method capable of suppressing the occurrence of unnecessary communication. [Means for solving the problem]

[0006] The terminal device of the present invention includes a communication unit that communicates with a target terminal device and a management device, a position detection unit that detects its own position information, a positioning request receiving unit that receives a positioning information request signal including a threshold of received radio wave strength and a required number of responses from the target terminal device via the communication unit, a condition determination unit that determines whether the received radio wave strength when the positioning information request signal is received from the target terminal device is equal to or greater than the threshold, and information relating to superiority information and a response waiting time is stored in advance, and when the condition determination unit determines that the received radio wave strength is equal to or greater than the threshold, a counting unit that counts the number of responses of positioning information signals which are responses to the positioning information request signal intercepted by a communication unit; a response number determination unit that determines whether the number of responses counted by the counting unit reaches the required number of responses after the response waiting time set by the time setting unit has elapsed; and a positioning information transmitting unit that transmits to a management device target positioning information including the location information and the received radio wave intensity at the time the positioning information request signal was received when the response number determination unit determines that the number of responses has not reached the required number of responses.

[0007] The communication control method of the present invention includes the steps of: detecting its own location information; receiving a positioning information request signal including a threshold value of received radio wave strength and a required number of responses from a target terminal device; a condition determination unit that determines whether the received radio wave strength when the positioning information request signal is received from the target terminal device is equal to or greater than the threshold; a condition determination unit that has information regarding superiority information and a response waiting time in advance, and when it is determined that the received radio wave strength is equal to or greater than the threshold, setting and measuring a response waiting time according to the received radio wave strength when the positioning information request signal is received and the superiority information; counting the number of responses of positioning information signals that are responses to the positioning information request signal; determining whether the counted number of responses has reached the required number of responses after the response waiting time has elapsed; and when it is determined that the number of responses has not reached the required number of responses, transmitting target positioning information to a management device, the target positioning information including the location information and the received radio wave strength when the positioning information request signal is received. Effect of the Invention

[0008] According to the present invention, it is possible to suppress the occurrence of unnecessary communications. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a communication system according to the present invention. [Diagram 2] FIG. 2 is a diagram for explaining an outline of the processing of the communication system according to the present invention. [Diagram 3] FIG. 3 is a diagram for explaining an outline of the processing of the communication system according to the present invention. [Figure 4] FIG. 4 is a diagram for explaining an outline of the processing of the communication system according to the present invention. [Diagram 5] FIG. 5 is a block diagram showing an example of the configuration of a management device according to the present invention. [Figure 6] FIG. 6 is a block diagram showing an example of the configuration of a terminal device according to the present invention. [Figure 7]FIG. 7 is a sequence diagram showing the flow of position information calculation processing in the communication system according to the first embodiment. [Figure 8] FIG. 8 is a flowchart showing the position calculation process of the management device according to the first embodiment. [Figure 9] FIG. 9 is a diagram for explaining a method for calculating the position of a target terminal device according to the first embodiment. [Figure 10] FIG. 10 is a diagram for explaining an overview of the processing of the communication system according to the second embodiment. [Figure 11] FIG. 11 is a sequence diagram showing the flow of position information calculation processing in the communication system according to the second embodiment. [Figure 12] FIG. 12 is a flowchart showing the position calculation process of the management device according to the second embodiment. [Figure 13] FIG. 13 is a sequence diagram showing the flow of position information calculation processing in the communication system according to the third embodiment. [Figure 14] FIG. 14 is a flowchart showing the position calculation process of the management device according to the third embodiment. [Figure 15] FIG. 15 is a block diagram illustrating an example of the configuration of a management device according to the fourth embodiment. [Figure 16] FIG. 16 is a sequence diagram showing the flow of position information calculation processing in the communication system according to the fourth embodiment. [Figure 17] FIG. 17 is a flowchart showing the position calculation process of the management device according to the fourth embodiment. [Figure 18] FIG. 18 is a sequence diagram showing the flow of position information calculation processing in the communication system according to the fifth embodiment. [Figure 19] FIG. 19 is a flowchart showing the position calculation process of the management device according to the fifth embodiment. [Figure 20] FIG. 20 is a diagram for explaining the positional relationship between the terminal device 12 and the target terminal device 14 according to a first modified example of the fifth embodiment. [Figure 21] FIG. 21 is a diagram for explaining a third modified example of superiority information according to the fifth embodiment. [Figure 22] FIG. 22 is a flowchart showing the process contents of the target terminal device and the terminal device according to the fifth embodiment. [Diagram 23] FIG. 23 is a flowchart showing the location information request process according to the fifth embodiment. [Figure 24] FIG. 24 is a flowchart showing the positioning process according to the fifth embodiment. [Diagram 25] FIG. 25 is a sequence diagram showing the flow of position information calculation processing in the communication system according to the sixth embodiment. [Figure 26] FIG. 26 is a flowchart showing the positioning process according to the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to this embodiment, and in the following embodiments, the same components are designated by the same reference numerals, and duplicated explanations will be omitted.

[0011] [First embodiment] (Communications Systems) An example of the configuration of a communication system according to the present invention will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of a communication system according to the present invention.

[0012] 1, the communication system 1 includes a management device 10, a plurality of terminal devices 12, and a target terminal device 14. The management device 10 calculates the position of the target terminal device 14 based on the position information of the plurality of terminal devices 12 and the received radio wave intensity of the signal received by the plurality of terminal devices 12 from the target terminal device 14.

[0013] (Processing Overview) An overview of the processing of the communication system according to the present invention will be described with reference to Fig. 2, Fig. 3, and Fig. 4. Fig. 2 to Fig. 4 are diagrams for explaining the overview of the processing of the communication system according to the present invention.

[0014] 2, the management device 10 transmits a location information request signal indicating a request for location information to the target terminal device 14 for which location information is to be calculated. The location information is information including the location of the target terminal device 14 and a response condition. The target terminal device 14 may be in various situations, such as a case where it has a function for measuring its own location, a case where it does not have a function for measuring its own location, or a case where it has a function for measuring its own location but is unable to measure its own location for reasons such as being inside a building.

[0015] As shown in FIG. 3, when the target terminal device 14 receives a position information request signal from the management device 10, it determines whether its own position information can be detected, and if it determines that the position information can be detected, it transmits the detected position information to the management device. If it determines that the position information cannot be detected, it transmits a positioning information request signal including a response condition to multiple terminal devices 12 in the vicinity. The positioning information request signal is a signal that requests only devices that satisfy the response condition to respond to the management device 10. In the example shown in FIG. 3, the target terminal device 14 transmits a positioning information request signal, and eight terminal devices 12, from the terminal device 12-1 to the terminal device 12-8, receive the positioning information request signal. The terminal devices 12-2, 12-4, 12-5, and 12-7 are located within a receiving range R11 within a first distance from the target terminal device 14. The terminal device 12-1, the terminal device 12-3, the terminal device 12-6, and the terminal device 12-8 are located within a receiving range R12 that is farther than the receiving range R11 and is within a second distance from the target terminal device 14. Here, a case will be described in which the response condition is that the received radio wave strength of the signal received from the target terminal device 14 is equal to or greater than a threshold. The receiving range R11 is a range in which the received radio wave strength of the signal received from the target terminal device 14 is equal to or greater than the threshold of the received radio wave strength, which is the response condition. The terminal device 12-1, the terminal device 12-2, the terminal device 12-5, and the terminal device 12-6 are terminal devices that have a function of locating their own positions. The terminal device 12-3, the terminal device 12-4, the terminal device 12-7, and the terminal device 12-8 are terminal devices that do not have a function of locating their own positions.

[0016] 4, terminal device 12-2 and terminal device 12-5, which are located within reception range R11 and have a function for measuring their own positions, transmit target positioning information including their own position information and the received radio wave intensity of a signal received from target terminal device 14 to management device 10. Management device 10 calculates the position of target terminal device 14 based on the target positioning information received from terminal device 12-2 and terminal device 12-5.

[0017] (Management device) An example of the configuration of a management device according to the present invention will be described with reference to Fig. 5. Fig. 5 is a block diagram showing an example of the configuration of a management device according to the present invention.

[0018] 5, the management device 10 includes a communication unit 20, a storage unit 22, and a control unit 24. The management device 10 is realized by, for example, an information processing device such as a personal computer.

[0019] The communication unit 20 performs communication between the management device 10 and an external device. For example, the communication unit 20 executes communication between the management device 10 and the terminal device 12 and the target terminal device 14. The communication unit 20 is realized by, for example, a wireless LAN (Local Area Network), a wired LAN, Wi-Fi (registered trademark), or the like.

[0020] The storage unit 22 stores various types of information. The storage unit 22 stores information such as the contents of calculations performed by the control unit 24 and programs. The storage unit 22 includes at least one of a RAM (Random Access Memory), a main storage device such as a ROM (Read Only Memory), and an external storage device such as an HDD (Hard Disk Drive).

[0021] The control unit 24 controls each unit of the management device 10. The control unit 24 has, for example, an information processing device such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and a storage device such as a RAM or a ROM. The control unit 24 executes a program that controls the operation of the management device 10 according to the present invention. The control unit 24 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control unit 24 may be realized by a combination of hardware and software.

[0022] The control unit 24 includes a location information request unit 30, a condition determination unit 32, a positioning information receiving unit , and a location calculation unit .

[0023] The location information request unit 30 transmits a location information request signal via the communication unit 20 to the target terminal device 14, the location of which is to be calculated.

[0024] If the target terminal device 14 cannot acquire location information when it receives the location information request signal, the condition determination unit 32 sets a response condition to be included in the positioning information request signal transmitted from the target terminal device 14. For example, the condition determination unit 32 determines the value of the response condition, which is that the received radio wave strength is equal to or greater than a predetermined threshold. The received radio wave strength is, for example, a Received Signal Strength Indicator (RSSI) value. Furthermore, the response condition may be a required number of responses, which is the number of responses from the target terminal device, in addition to the threshold of the received radio wave strength being equal to or greater than a predetermined threshold.

[0025] The positioning information receiving unit 34 receives target positioning information from a terminal device 12 whose received radio wave strength when receiving a positioning information request signal from the target terminal device 14 is equal to or greater than a threshold, including location information of the terminal device itself and the received radio wave strength when receiving the positioning information from the target terminal device 14. Specifically, the positioning information receiving unit 34 receives target positioning information from each of the multiple terminal devices 12.

[0026] The position calculation unit 36 ​​calculates the position of the target terminal device 14 based on the target positioning information received by the positioning information receiving unit 34. Specifically, the position calculation unit 36 ​​calculates the position of the target terminal device 14 based on the multiple pieces of target positioning information received by the positioning information receiving unit 34. The number of pieces of target positioning information is preferably three or more, but is not limited to this.

[0027] (Terminal Device) An example of the configuration of a terminal device according to the present invention will be described with reference to Fig. 6. Fig. 6 is a block diagram showing an example of the configuration of a terminal device according to the present invention.

[0028] 6, the terminal device 12 includes an input unit 60, an audio input unit 62, a display unit 64, an audio output unit 66, a communication unit 68, a storage unit 70, a GNSS (Global Navigation Satellite System) receiving unit 72, a battery remaining amount detection unit 73, and a control unit 74. The terminal device 12 is, for example, a business wireless communication device, a mobile phone, a smartphone, a tablet terminal, or the like, but is not limited to these.

[0029] The input unit 60 accepts various operations for the terminal device 12. The input unit 60 is realized by various input devices such as a switch, a button, or a touch panel.

[0030] The voice input unit 62 detects the voice of the user who is using the terminal device 12. The voice input unit 62 converts the detected voice into a voice signal. The voice input unit 62 is realized by a microphone.

[0031] The display unit 64 displays various types of information. The display unit 64 is realized by a display including, for example, a liquid crystal display or an organic EL (Electro-Luminescence) display.

[0032] The audio output unit 66 is a speaker that outputs various types of audio, for example, the audio of the communication partner.

[0033] The communication unit 68 is a communication interface that performs communication between the terminal device 12 and an external device. For example, the communication unit 68 executes communication between the terminal device 12 and the management device 10 and the target terminal device 14. The communication unit 68 is realized by, for example, a wireless LAN, Wi-Fi (registered trademark), or the like.

[0034] The storage unit 70 stores various types of information. The storage unit 70 stores information such as the contents of calculations performed by the control unit 74 and programs. The storage unit 70 includes at least one of a RAM, a main storage device such as a ROM, and an external storage device such as a HDD.

[0035] The GNSS receiving unit 72 is composed of a GNSS receiver that receives GNSS signals from GNSS satellites, etc. The GNSS receiving unit 72 periodically outputs the received GNSS signals to a position detection unit 80 of the control unit 74.

[0036] The battery remaining capacity detection unit 73 detects the remaining battery capacity of the terminal device itself.

[0037] The control unit 74 controls each unit of the terminal device 12. The control unit 74 has, for example, an information processing device such as a CPU or an MPU, and a storage device such as a RAM or a ROM. The control unit 74 executes a program that controls the operation of the terminal device 12 according to the present invention. The control unit 74 may be realized by an integrated circuit such as an ASIC or an FPGA. The control unit 74 may be realized by a combination of hardware and software.

[0038] The control unit 74 includes a position detection unit 80 , a position measurement information receiving unit 82 , a condition determination unit 84 , a time setting unit 86 , a counting unit 88 , a response number determination unit 90 , and a position measurement information transmitting unit 92 .

[0039] The position detection unit 80 detects current position information of the terminal device 12. Specifically, the position detection unit 80 detects the current position information and the position information degradation degree of the terminal device itself, based on the GNSS signal received by the GNSS receiving unit 72.

[0040] The position measurement information receiving unit 82 receives a position information request signal including a threshold of received radio wave strength and a required number of responses from the management device 10, or a position measurement information request signal including a threshold of received radio wave strength and a required number of responses from the target terminal device 14, via the communication unit 68. The required number of responses is the number of target positioning information pieces necessary for the management device 10 to calculate the position of the target terminal device 14.

[0041] The condition determination unit 84 determines whether or not location information can be acquired when a location information request signal is received from the management device 10. The condition determination unit 84 also determines the received radio wave strength of the signal received by the terminal device 12, and determines whether or not the received radio wave strength of the signal received by the terminal device 12 is equal to or greater than a threshold. For example, the condition determination unit 84 determines whether or not the received radio wave strength is equal to or greater than a threshold when the location positioning information receiving unit 82 receives a positioning information request signal from the target terminal device 14.

[0042] The time setting unit 86 sets the response waiting time based on the priority information. The priority information is information acquired by the target terminal device 14. The response waiting time is a time indicating the timing at which the position measurement information receiving unit 82 transmits the target position measurement information to the management device 10 after receiving the position information request signal.

[0043] A case will be described in which the superior information is the received radio wave strength when the positioning information receiving unit 82 receives a positioning information request signal from the target terminal device 14. For example, when the received radio wave strength is 0 [dBm (decibels milliwatts)] to -50 [dBm], the time setting unit 86 sets the waiting time to "small". The waiting time "small" is, for example, 0 seconds, but is not limited to this. For example, when the received radio wave strength is -51 [dBm] to -70 [dBm], the time setting unit 86 sets the waiting time to "medium". The waiting time "medium" is, for example, 30 seconds, but is not limited to this. For example, when the received radio wave strength is -71 [dBm] to -90 [dBm], the time setting unit 86 sets the waiting time to "large". The waiting time "large" is, for example, 60 seconds, but is not limited to this. That is, the stronger the received radio wave strength is, the shorter the waiting time is set, and the weaker the received radio wave strength is, the longer the waiting time is set. Although the waiting time is set in three stages according to the received radio wave strength, the present invention is not limited to this. For example, the time setting unit 86 may set the waiting time in three or more stages by narrowing the range of the received radio wave strength for setting the waiting time, or may set the waiting time continuously according to the received radio wave strength. This makes it possible to prevent the timing of transmitting the target positioning information from overlapping between multiple terminal devices 12.

[0044] A case where the superior information is the remaining battery level detected by the battery remaining level detection unit 73 of the terminal device 12 will be described. For example, when the remaining battery level is between 100[%] and 80[%], the time setting unit 86 sets the waiting time to "small". For example, when the remaining battery level is between 79[%] and 50[%], the time setting unit 86 sets the waiting time to "medium". For example, when the remaining battery level is between 49[%] and 0[%], the time setting unit 86 sets the waiting time to "large". That is, the time setting unit 86 sets the waiting time to be shorter as the remaining battery level is higher, and sets the waiting time to be longer as the remaining battery level is lower. Note that the waiting time is set in three stages according to the remaining battery level, but the present invention is not limited to this. For example, the time setting unit 86 may set the waiting time to be in three or more stages by setting the range of the remaining battery level for setting the waiting time to be shorter, or may set the waiting time continuously according to the remaining battery level. This makes it possible to prevent the timing of transmitting the target positioning information from overlapping between the multiple terminal devices 12.

[0045] A case where the superior information is the degree of degradation of positional accuracy included in the GNSS signal of the terminal device 12 will be described. For example, when the degree of degradation of positional accuracy is 1.0 to 3.0, the time setting unit 86 sets the waiting time to "small". For example, when the degree of degradation of positional accuracy is 3.1 to 6.0, the time setting unit 86 sets the waiting time to "medium". For example, when the degree of degradation of positional accuracy is 6.1 or more, the time setting unit 86 sets the waiting time to "large". That is, the higher the position accuracy, the shorter the waiting time is set by the time setting unit 86, and the lower the position accuracy, the longer the waiting time is set. Note that, although the waiting time is set in three stages according to the degree of degradation of positional accuracy, the present invention is not limited to this. For example, the time setting unit 86 may set the waiting time to three or more stages by setting the width of the degree of degradation of positional accuracy for setting the waiting time to be short, or may set the waiting time continuously according to the degree of degradation of positional accuracy. This makes it possible to suppress overlapping of the timing of transmitting the target positioning information between a plurality of terminal devices 12.

[0046] In the present invention, the superior information is not limited to the received radio wave intensity when the position measurement information receiving unit 82 receives a position measurement information request signal from the target terminal device 14, the remaining battery level of the terminal device 12, and the degree of deterioration of the position accuracy of the terminal device 12.

[0047] The counting unit 88 counts the number of responses to the positioning information request signal. Specifically, the counting unit 88 counts the number of pieces of target positioning information transmitted to the management device 10 in response to the positioning information request signal. In other words, the counting unit 88 counts the number of other terminal devices 12 that have transmitted target positioning information to the management device 10 in response to the positioning information request signal.

[0048] A response number determination unit 90 determines whether or not the number of responses counted by the counting unit 88 has reached the required number of responses when the response waiting time set by the time setting unit 86 has elapsed.

[0049] The positioning information transmitting unit 92 transmits, via the communication unit 68, to the management device 10, target position information including the position information of the terminal device 12 and the received radio wave intensity when a positioning information request signal is received from the target terminal device 14. Specifically, when the response number determining unit 90 determines that the number of responses has not reached the required number of responses, the positioning information transmitting unit 92 transmits the target positioning information to the management device 10 via the communication unit 68. When a response waiting time is set by the time setting unit 86, the positioning information transmitting unit 92 transmits the target positioning information to the management device 10 after the response waiting time has elapsed.

[0050] (Target terminal device) The target terminal device 14 is, for example, but not limited to, a business wireless communication device, a mobile phone, a smartphone, a tablet terminal, etc. When the communication unit 68 of the target terminal device 14 receives a position information request signal from the management device 10, the communication unit 68 determines whether or not the position information can be detected by the position detection unit 80 of the control unit 74. If it is determined that the position detection unit 80 cannot detect its own position information, the target terminal device 14 transmits a positioning information request signal indicating a request for positioning information to multiple terminal devices 12 in the vicinity.

[0051] [First embodiment] The location information calculation process of the communication system according to the first embodiment will be described with reference to Fig. 7. Fig. 7 is a sequence diagram showing the flow of the location information calculation process of the communication system according to the first embodiment. In the first embodiment, the response condition is a case where the received radio wave intensity is equal to or greater than a threshold value.

[0052] 7 shows a process in which the management device 10 calculates the position of the target terminal device 14 using information received from three terminal devices 12, the terminal device 12a, the terminal device 12b, and the terminal device 12c. The terminal devices 12a, 12b, and 12c have the same configuration as the terminal device 12 shown in FIG.

[0053] The condition determination unit 32 of the management device 10 sets an initial response condition (step S10). Specifically, the condition determination unit 32 of the management device 10 sets an initial value of a threshold of received radio wave strength indicating a response condition for a positioning information request signal that the target terminal device 14 transmits to the terminal device 12 when the location information request signal is received. Then, the condition determination unit 32 of the management device 10 sets a condition that the received radio wave strength is equal to or greater than the set threshold as the initial response condition.

[0054] The location information requesting unit 30 of the management device 10 transmits a location information request signal including an initial response condition to the target terminal device 14 via the communication unit 20 (step S12).

[0055] The target terminal device 14 transmits a positioning information request signal including an initial response condition to the terminal device 12a, the terminal device 12b, and the terminal device 12c (step S14).

[0056] The condition determination unit 84 of the terminal device 12a measures the received radio wave strength when the positioning information receiving unit 82 receives a positioning information request signal from the target terminal device 14 (step S16a). The condition determination unit 84 of the terminal device 12a determines whether the measured received radio wave strength is equal to or greater than the threshold of the received radio wave strength set by the management device 10 (step S18a). Here, the condition determination unit 84 of the terminal device 12a determines that the measured received radio wave strength is equal to or greater than the threshold of the received radio wave strength set by the management device 10.

[0057] The position detection unit 80 of the terminal device 12a detects the current position of the terminal device 12a (step S20a). Specifically, the position detection unit 80 of the terminal device 12a detects the current position of the terminal device 12a based on the GNSS signal received by the GNSS receiver 72.

[0058] The positioning information transmission unit 92 of the terminal device 12a transmits the target positioning information, which includes location information indicating the current location of the terminal device 12a and the received radio wave intensity measured by the condition determination unit 84, to the management device 10 via the communication unit 68 (step S22a).

[0059] Steps S16b, S18b, S20b, and S22b are the same as steps S16a, S18a, S20a, and S22a, except that the terminal device 12b is the main terminal device, and therefore a description thereof will be omitted.

[0060] Steps S16c, S18c, S20c, and S22c are the same as steps S16a, S18a, S20a, and S22a, except that the terminal device 12c is the main terminal device, and therefore the description thereof will be omitted.

[0061] The position calculation unit 36 ​​of the management device 10 calculates the position of the target terminal device 14 based on the target positioning information received from the terminal device 12a, the terminal device 12b, and the terminal device 12c (step S24).

[0062] (Management device processing) The position calculation process of the management device according to the first embodiment will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the position calculation process of the management device according to the first embodiment.

[0063] The condition determination unit 32 sets, as a response condition, an initial value of a threshold value of received radio wave intensity indicating a response condition for a positioning information request signal that the target terminal device 14 transmits to the terminal device 12 when the position information request signal is received (step S30). Then, the process proceeds to step S32.

[0064] The location information request unit 30 transmits a location information request signal to the target terminal device 14 (step S32), and then the process proceeds to step S34.

[0065] The positioning information receiving unit 34 receives the target positioning information from the multiple terminal devices 12 (step S34). Then, the process proceeds to step S36.

[0066] The position calculation unit 36 ​​calculates the position of the target terminal device 14 based on the multiple pieces of target positioning information received by the positioning information receiving unit 34 (step S36). FIG. 9 is a diagram for explaining a method for calculating the position of the target terminal device according to the first embodiment. In FIG. 9, the management device 10 receives target positioning information from the terminal device 12a, the terminal device 12b, and the terminal device 12c. The position calculation unit 36 ​​calculates that the target terminal device 14 is located within an area R1 of a circle with a radius of r1 based on the target positioning information received from the terminal device 12a. The position calculation unit 36 ​​calculates that the target terminal device 14 is located within an area R2 of a circle with a radius of r2 based on the target positioning information received from the terminal device 12b. The position calculation unit 36 ​​calculates that the target terminal device 14 is located within an area R3 of a circle with a radius of r3 based on the target positioning information received from the terminal device 12c. The larger the received radio wave intensity, the smaller the size of the circle, and the smaller the received radio wave intensity, the larger the size of the circle. In the example shown in Fig. 9, the position calculation unit 36 ​​calculates that the target terminal device 14 is located within a predetermined area R4 centered on the intersection of areas R1, R2, and R3. Then, the process in Fig. 8 ends.

[0067] As described above, the first embodiment calculates the position of the target terminal device 14 based on the position information of the terminal device 12 in which the received radio wave strength of the signal received from the target terminal device 14 is equal to or greater than the threshold value, and the received radio wave strength. This makes it possible for the first embodiment to accurately calculate the position of the target terminal device 14 while suppressing the occurrence of unnecessary communication.

[0068] [Second embodiment] A second embodiment will be described. FIG. 10 is a diagram for explaining an overview of the processing of the communication system according to the second embodiment. In the second embodiment, the response condition is a case where the received radio wave intensity is equal to or greater than a threshold value. In the example shown in FIG. 4, the management device 10 may not be able to receive target positioning information from a terminal device located within the reception range R11, and may not be able to calculate the position of the target terminal device 14. In such a case, as shown in FIG. 10, the management device 10 changes the initial response condition, receives target positioning information from the terminal device 12-1 and the terminal device 12-6 located within the reception range R12, and calculates the position of the target terminal device 14.

[0069] (Location information calculation process) A location information calculation process in the communication system according to the second embodiment will be described with reference to Fig. 11. Fig. 11 is a sequence diagram showing the flow of location information calculation process in the communication system according to the second embodiment.

[0070] The processes from step S40 to step S44 are the same as the processes from step S10 to step S14 shown in FIG. 7, respectively, and therefore will not be described.

[0071] The processes from step S46a to step S52a are the same as the processes from step S16a to step S22a shown in FIG. 7, respectively, and therefore will not be described.

[0072] The processes from step S46b to step S52b are the same as the processes from step S16b to step S22b shown in FIG. 7, respectively, and therefore will not be described.

[0073] The process of step S46c is the same as the process of step S16c shown in Fig. 7, so the description will be omitted. The condition determination unit 84 of the terminal device 12c measures the received radio wave strength when the position measurement information receiving unit 82 receives a position measurement information request signal from the target terminal device 14 (step S48c). Here, the condition determination unit 84 of the terminal device 12c determines that the measured received radio wave strength is less than the threshold of the received radio wave strength set by the management device 10. In this case, the terminal device 12c does not transmit the target position measurement information to the management device 10.

[0074] The position calculation unit 36 ​​of the management device 10 determines that it is not possible to calculate the position of the target terminal device 14 because the number of pieces of target positioning information is small (step S54). Here, for example, it is assumed that three or more pieces of target positioning information are required to calculate the position of the target terminal device 14. The number of pieces of target positioning information required to calculate the position of the target terminal device 14 may be set arbitrarily. Then, the process proceeds to step S56.

[0075] The condition determination unit 32 of the management device 10 changes the initial response condition (step S56). Specifically, the condition determination unit 32 of the management device 10 sets a condition that the received radio wave strength is less than a set threshold as the changed condition. For example, the condition determination unit 32 of the management device 10 may change the threshold of the received radio wave strength set as the initial response condition to a smaller value.

[0076] The location information requesting unit 30 of the management device 10 transmits a location information request signal including the changed response condition to the target terminal device 14 via the communication unit 20 (step S58).

[0077] The target terminal device 14 transmits a positioning information request signal including the changed response condition to the terminal device 12a, the terminal device 12b, and the terminal device 12c (step S60).

[0078] The condition determination unit 84 of the terminal device 12a measures the received radio wave strength when the position measurement information receiving unit 82 receives a position measurement information request signal from the target terminal device 14 (step S62a). The condition determination unit 84 of the terminal device 12a determines whether the measured received radio wave strength is less than the threshold of the received radio wave strength set by the management device 10 (step S64a). Here, the condition determination unit 84 of the terminal device 12a determines that the measured received radio wave strength is equal to or greater than the threshold of the received radio wave strength set by the management device 10. In this case, the terminal device 12a does not transmit the target position measurement information to the management device 10.

[0079] The processes in steps S62b and S64b are the same as those in steps S62a and S64a, respectively, except that the subject is the terminal device 12b, and therefore a description thereof will be omitted.

[0080] The processes of steps S62c and S64c are the same as those of steps S62a and S64a, respectively, except that the subject is terminal device 12c, and therefore will not be described. In step S64c, condition determination unit 84 of terminal device 12c determines that the measured received radio wave strength is less than the threshold of received radio wave strength set by management device 10.

[0081] The position detection unit 80 of the terminal device 12c detects the current position of the terminal device 12c (step S66c). Specifically, the position detection unit 80 of the terminal device 12c detects the current position of the terminal device 12c based on the GNSS signal received by the GNSS receiver 72.

[0082] The positioning information transmission unit 92 of the terminal device 12c transmits the target positioning information, which includes location information indicating the current location of the terminal device 12c and the received radio wave intensity measured by the condition determination unit 84, to the management device 10 via the communication unit 68 (step S68).

[0083] The position calculation unit 36 ​​of the management device 10 calculates the position of the target terminal device 14 based on the target positioning information received from the terminal device 12a and the terminal device 12b under the initial response conditions and the target positioning information received from the terminal device 12c under the changed conditions (step S70).

[0084] (Management device processing) The position calculation process of the management device according to the second embodiment will be described with reference to Fig. 12. Fig. 12 is a flowchart showing the position calculation process of the management device according to the second embodiment.

[0085] The processes from step S80 to step S84 are the same as the processes from step S30 to step S34 shown in FIG. 8, respectively, and therefore will not be described.

[0086] The position calculation unit 36 ​​judges whether or not the position of the target terminal device 14 can be calculated (step S86). Specifically, the position calculation unit 36 ​​judges that the position of the target terminal device 14 can be calculated when the positioning information receiving unit 34 receives the number of target positioning information required to calculate the position of the target terminal device 14. If it is judged that the position of the target terminal device 14 can be calculated (step S86; Yes), the process proceeds to step S88. If it is not judged that the position of the target terminal device 14 can be calculated (step S86; No), the process proceeds to step S90.

[0087] If it is determined as Yes in step S86, the position calculation unit 36 ​​calculates the position of the target terminal device 14 based on the target positioning information (step S88), and then ends the processing in FIG.

[0088] If the result of the determination in step S86 is No, the condition determination unit 32 updates the response condition (step S90). Specifically, the condition determination unit 32 changes the condition of the threshold of the received radio wave strength set in step S30. For example, the condition determination unit 32 changes the condition that the threshold of the received radio wave strength is equal to or greater than the threshold to the condition that the received radio wave strength is less than the threshold. Then, the process proceeds to step S82.

[0089] As described above, in the second embodiment, when the number of pieces of target positioning information required to calculate the position of the target terminal device cannot be received, the response condition is changed to make it easier to receive the target positioning information. This allows the second embodiment to properly calculate the position of the target terminal device.

[0090] [Third embodiment] A third embodiment will be described. In the third embodiment, the response condition is a case where the received radio wave strength is equal to or greater than a threshold. The management device 10 uses the location information of the terminal device 12 when calculating the location of the target terminal device 14, but the calculation result of the location of the target terminal device 14 may differ depending on the accuracy of the location information of the terminal device 12. Therefore, in the third embodiment, the location of the target terminal device 14 is calculated taking into account the detection accuracy of the terminal device 12's own location.

[0091] (Location information calculation process) A location information calculation process in the communication system according to the third embodiment will be described with reference to Fig. 13. Fig. 13 is a sequence diagram showing the flow of location information calculation process in the communication system according to the third embodiment.

[0092] The condition determination unit 32 of the management device 10 sets an initial response condition (step S100). Specifically, the condition determination unit 32 of the management device 10 sets an initial value of the threshold of received radio wave strength and an initial value of the threshold of position accuracy, which indicate response conditions to a positioning information request signal that the target terminal device 14 transmits to the terminal device 12 when the target terminal device 14 receives a position information request signal. In this embodiment, for example, the position accuracy is expressed by a position accuracy degradation degree (PDOP: Position Dilution of Precision). The condition determination unit 32 of the management device 10 sets a condition that the received radio wave strength is equal to or greater than the set threshold as the initial response condition. The condition determination unit 32 of the management device 10 sets a condition that the position accuracy degradation degree is less than the threshold.

[0093] The processes in steps S102 and S104 are the same as those in steps S12 and S14 shown in FIG. 7, respectively, and therefore will not be described.

[0094] The process of step S106a is the same as the process of step S16a shown in FIG. 7, and therefore a description thereof will be omitted.

[0095] The position detection unit 80 of the terminal device 12a judges the degree of degradation of the position accuracy (step S108a). Specifically, the position detection unit 80 of the terminal device 12a measures the degree of degradation of the position accuracy based on, for example, the GNSS signal received by the GNSS receiving unit 72. The condition determination unit 84 of the terminal device 12a judges whether the measured received radio wave strength is equal to or greater than the threshold value of the received radio wave strength set by the management device 10 and the degree of degradation of the position accuracy is equal to or less than a predetermined value (step S110a). Here, the condition determination unit 84 of the terminal device 12a judges that the measured received radio wave strength is equal to or greater than the threshold value of the received radio wave strength set by the management device 10 and the degree of degradation of the position accuracy is not equal to or less than a predetermined value. In this case, the terminal device 12a does not transmit the target positioning information to the management device 10.

[0096] The processing from step S106b to step S110b is the same as the processing from step S106a to step S110a, except that the subject is terminal device 12b, and therefore a description thereof will be omitted. In step S110b, condition determination unit 84 of terminal device 12b determines that the measured received radio wave strength is equal to or greater than the threshold value of the received radio wave strength set by management device 10, and that the degree of degradation of location accuracy is equal to or less than a predetermined level.

[0097] The positioning information transmission unit 92 of the terminal device 12b transmits, via the communication unit 68, the target positioning information including location information indicating the current location of the terminal device 12b, the received radio wave strength measured by the condition determination unit 84, and the degree of degradation in location accuracy measured by the location detection unit 80 to the management device 10 (step S114b).

[0098] The processes of steps S106c, S108c, S110c, S112c, and S114c are the same as the processes of steps S106b, S108b, S110b, S112b, and S114b, respectively, except that the subject is the terminal device 12c, and therefore description thereof will be omitted.

[0099] The processes of steps S106d, S108d, S110d, S112d, and S114d are the same as the processes of steps S106b, S108b, S110b, S112b, and S114b, respectively, except that the subject is the terminal device 12d, and therefore description thereof will be omitted.

[0100] The position calculation unit 36 ​​of the management device 10 calculates the position of the target terminal device 14 based on the target positioning information received from the terminal device 12b, the terminal device 12c, and the terminal device 12d (step S116).

[0101] (Management device processing) The position calculation process of the management device according to the third embodiment will be described with reference to Fig. 14. Fig. 14 is a flowchart showing the position calculation process of the management device according to the third embodiment.

[0102] The condition determination unit 32 sets, as response conditions, an initial value of the threshold of received radio wave intensity and a threshold of the degree of degradation of position accuracy, which indicate response conditions for a positioning information request signal that the target terminal device 14 transmits to the terminal device 12 when the target terminal device 14 receives the position information request signal (step S120).Then, the process proceeds to step S122.

[0103] The processing from step S122 to step S126 is the same as the processing from step S32 to step S36 shown in FIG. 8, and therefore the description thereof will be omitted.

[0104] As described above, in the third embodiment, the position of the target terminal device 14 is calculated taking into account the degree of degradation in position accuracy in addition to the received radio wave strength. This makes it possible for the third embodiment to accurately calculate the position of the target terminal device 14.

[0105] [Fourth embodiment] A fourth embodiment will be described. In the fourth embodiment, the response condition is a case where the received radio wave intensity is equal to or greater than a threshold. In the fourth embodiment, the position of the target terminal device 14 is calculated using the target positioning information measured by the management device 10 in addition to the target positioning information measured by the terminal device 12.

[0106] An example of the configuration of a management device according to the fourth embodiment will be described with reference to Fig. 15. Fig. 15 is a block diagram showing an example of the configuration of a management device according to the fourth embodiment.

[0107] As shown in FIG. 15, the management device 10A differs from the management device 10 shown in FIG. 5 in that it includes a GNSS receiver 26 and that the control unit 24A includes a position measurement information receiver 38, a position detector 40, and a radio wave intensity determination unit 42.

[0108] The GNSS receiving unit 26 is configured with a GNSS receiver that receives GNSS signals from GNSS satellites, etc. The GNSS receiving unit 26 outputs the received GNSS signals to a position detection unit 40 of the control unit 24A.

[0109] The position measurement information receiving unit 38 receives a position measurement information request signal from the target terminal device 14 via the communication unit 20 .

[0110] The position detection unit 40 detects the current position information of the management device 10. Specifically, the position detection unit 40 detects the current position information of the management device 10 based on the GNSS signal received by the GNSS receiving unit 26.

[0111] When the position of the management device 10 is fixed, the position detection unit 40 may detect the position information of the management device 10 based on the position information of the management device 10 stored in the storage unit 22. In this case, the management device 10 does not need to include the GNSS receiving unit 26.

[0112] The radio wave strength determination unit 42 determines the received radio wave strength of the signal received by the management device 10. The radio wave strength determination unit 42 determines whether or not the received radio wave strength of the signal received by the management device 10 is equal to or greater than a threshold. For example, the radio wave strength determination unit 42 determines whether or not the received radio wave strength when a positioning information request signal is received is equal to or greater than a threshold.

[0113] If the received radio wave strength at the time when the management device 10A receives the location information request signal is equal to or greater than a threshold value, the management device 10A calculates the location of the target terminal device 14 using the target side information measured by the management device 10A.

[0114] (Location information calculation process) A location information calculation process in the communication system according to the fourth embodiment will be described with reference to Fig. 16. Fig. 16 is a sequence diagram showing the flow of location information calculation process in the communication system according to the fourth embodiment.

[0115] The processes in steps S130 and S132 are the same as those in steps S10 and S12 shown in FIG. 7, respectively, and therefore will not be described.

[0116] The target terminal device 14 transmits a positioning information request signal including an initial response condition to the management device 10, the terminal device 12a, the terminal device 12b, and the terminal device 12c (step S134).

[0117] The radio wave strength determination unit 42 of the management device 10 measures the received radio wave strength when it receives a positioning information request signal from the target terminal device 14 (step S136). The radio wave strength determination unit 42 of the management device 10 determines whether the measured received radio wave strength is valid for calculating the position of the management device 10 (step S138). Specifically, the radio wave strength determination unit 42 of the management device 10 determines whether the measured received radio wave strength is equal to or greater than a threshold value of the received radio wave strength set by the management device 10. Here, the management device 10 determines that the measured received radio wave strength is valid for calculating the position of the management device 10.

[0118] The position detection unit 40 of the management device 10 detects the current position of the management device 10 (step S139).

[0119] The processes of steps S140a, S142a, S144a, and S146a are the same as the processes of steps S16a, S18a, S20a, and S22a shown in FIG. 7, respectively, and therefore will not be described.

[0120] The processes of steps S140b, S142b, S144b, and S146b are the same as the processes of steps S16b, S18b, S20b, and S22b shown in FIG. 7, respectively, and therefore will not be described.

[0121] The processes of steps S140c and S142c are the same as the processes of steps S16c and S18c shown in Fig. 7, respectively, and therefore will not be described. Here, the condition determination unit 84 of the terminal device 12c determines that the measured received radio wave strength is less than the threshold value of the received radio wave strength set by the management device 10. In this case, the terminal device 12c does not transmit the target positioning information to the management device 10.

[0122] The position calculation unit 36 ​​of the management device 10A calculates the position of the target terminal device 14 based on the target positioning information measured by the management device 10A and the target positioning information received from the terminal device 12a and the terminal device 12b (step S148).

[0123] (Management device processing) The position calculation process of the management device according to the fourth embodiment will be described with reference to Fig. 17. Fig. 17 is a flowchart showing the position calculation process of the management device according to the fourth embodiment.

[0124] The processes in steps S160 and S162 are the same as those in steps S30 and S32 shown in FIG. 8, respectively, and therefore will not be described.

[0125] The position measurement information receiving unit 38 receives the position measurement information request signal from the target terminal device 14 (step S164). Then, the process proceeds to step S166.

[0126] The radio wave intensity determination unit 42 determines whether or not the received radio wave intensity when the position measurement information receiving unit 38 receives the position measurement information request signal is equal to or greater than a threshold (step S166), and then the process proceeds to step S168.

[0127] The radio wave strength determination unit 42 determines whether the measured received radio wave strength satisfies the condition (step S168). Specifically, the radio wave strength determination unit 42 determines whether the measured received radio wave strength is equal to or greater than the received radio wave strength set in step S160. If it is determined that the measured received radio wave strength satisfies the condition (step S168; Yes), the process proceeds to step S170. If it is determined that the measured received radio wave strength does not satisfy the condition (step S168; No), the process proceeds to step S172.

[0128] If the result of the determination in step S168 is Yes, the position detection unit 40 detects the position of the management device 10 (step S170), and the process then proceeds to step S172.

[0129] The positioning information receiving unit 34 receives the target positioning information from the multiple terminal devices 12 (step S172). Then, the process proceeds to step S174.

[0130] The position calculation unit 36 ​​calculates the position of the target terminal device 14 based on the position information detected by the position detection unit 40, the received radio wave intensity measured by the radio wave intensity determination unit 42, and the multiple pieces of target positioning information received by the positioning information receiving unit 34 (step S174). Then, the process of FIG. 17 ends.

[0131] As described above, in the fourth embodiment, the position of the target terminal device 14 is calculated using the self-positioning information of the management device 10 in addition to the target positioning information of the terminal device 12. As a result, in the fourth embodiment, the amount of communication between the management device 10 and the terminal device 12 can be reduced.

[0132] [Fifth embodiment] A fifth embodiment will be described. In the fifth embodiment, the response conditions are that the received radio wave intensity is equal to or greater than a threshold and that the number of responses required is a predetermined number. In the fifth embodiment, a priority order is set between a plurality of terminal devices 12 when transmitting target positioning information to the management device 10.

[0133] (Location information calculation process) The position information calculation process of the communication system according to the fifth embodiment will be described with reference to Fig. 18. Fig. 18 is a sequence diagram showing the flow of the position information calculation process of the communication system according to the fifth embodiment.

[0134] The condition determination unit 32 of the management device 10 sets an initial response condition (step S180). Specifically, the condition determination unit 32 of the management device 10 sets an initial value of a threshold of received radio wave intensity and a required number of responses, which indicate a response condition for a positioning information request signal that the target terminal device 14 transmits to the terminal device 12 when the location information request signal is received. Here, the required number of responses is assumed to be three, but is not limited to this.

[0135] The processes in steps S182 and S184 are the same as those in steps S12 and S14 shown in FIG. 7, respectively, and therefore will not be described.

[0136] The processes in steps S186a and S188a are the same as those in steps S16a and S18a shown in FIG. 7, respectively, and therefore will not be described.

[0137] The counting unit 88 of the terminal device 12a starts counting the number of responses to the positioning information request signal (step S190a). Specifically, the counting unit 88 of the terminal device 12a starts counting the number of other terminal devices 12 that have transmitted target positioning information in response to the positioning information request signal.

[0138] The time setting unit 86 of the terminal device 12a sets the response waiting time based on the predetermined priority information (step S192a). Here, it is assumed that the time setting unit 86 of the terminal device 12a sets the response waiting time to 60 seconds.

[0139] The processes of steps S186b, S188b, S190b, and S192b are the same as those of steps S186a, S188a, S190a, and S192a, respectively, except that the subject is the terminal device 12b, and therefore the explanation will be omitted. In step S192b, the time setting unit 86 of the terminal device 12b sets the response waiting time to 30 seconds.

[0140] The processes of steps S186c, S188c, S190c, and S192c are the same as the processes of steps S186a, S188a, S190a, and S192a, respectively, except that the subject is the terminal device 12c, and therefore the explanation will be omitted. In step S192c, the time setting unit 86 of the terminal device 12b sets the response waiting time to 0 seconds.

[0141] The response number determination unit 90 of the terminal device 12c determines the number of responses to the positioning information request signal after the response waiting time set by the time setting unit 86 has elapsed (step S194c). Since the response number is "0" here, the response number determination unit 90 of the terminal device 12c determines that a response is possible.

[0142] The process of step S196c is the same as the process of step S20c shown in FIG. 7, and therefore a description thereof will be omitted.

[0143] The positioning information transmitting unit 92 of the terminal device 12c transmits the target positioning information to the management device 10, the terminal device 12a, the terminal device 12b, and the terminal device 12d via the communication unit 68 (step S198c). Each terminal device 12 receives the target positioning information from the other terminal devices 12, and thereby can count the number of responses to the positioning information request signal.

[0144] The processes of steps S186d, S188d, S190d, S192d, S194d, S196d, and S198d are the same as the processes of steps S186c, S188c, S190c, S192c, S194c, S196c, and S198c, respectively, except that the subject is the terminal device 12d, so the description will be omitted. In step S194d, since the number of responses is "1", the response number determination unit 90 of the terminal device 12d determines that a response is possible. In step S198d, the positioning information transmission unit 92 of the terminal device 12d transmits the target positioning information to the management device 10, the terminal device 12a, the terminal device 12b, and the terminal device 12c via the communication unit 68.

[0145] The processes of steps S194b, S196b, and S198b are the same as those of steps S194c, S196c, and S198c, respectively, except that the subject is the terminal device 12b, and therefore the description will be omitted. In step S194d, since the number of responses is "2", the response number determination unit 90 of the terminal device 12b determines that a response is possible. In step S198b, the positioning information transmission unit 92 of the terminal device 12b transmits the target positioning information to the management device 10, the terminal device 12a, the terminal device 12c, and the terminal device 12d via the communication unit 68.

[0146] The position calculation unit 36 ​​of the management device 10 calculates the position of the target terminal device 14 based on the target positioning information received from the terminal device 12b, the terminal device 12c, and the terminal device 12d (step S200).

[0147] The process of step S194a is the same as the process of step S194c except that the subject is the terminal device 12a, so the explanation is omitted. In step S194a, since the number of responses is "3", the response number determination unit 90 of the terminal device 12a determines that a response is not possible. Therefore, the terminal device 12a does not transmit the target positioning information to the management device 10.

[0148] (Management device processing) The position calculation process of the management device according to the fifth embodiment will be described with reference to Fig. 19. Fig. 19 is a flowchart showing the position calculation process of the management device according to the fifth embodiment.

[0149] The condition determination unit 32 sets, as response conditions, an initial value of the threshold of received radio wave intensity indicating a response condition for a positioning information request signal that the target terminal device 14 transmits to the terminal device 12 when the position information request signal is received, and a required number of responses for the target positioning information (step S210).Then, the process proceeds to step S212.

[0150] The processes in steps S212 and S214 are the same as those in steps S212 and S214 shown in FIG. Since this is the same as the processing in steps S32 and S34, the explanation will be omitted.

[0151] The position calculation unit 36 ​​judges whether the number of pieces of target positioning information received by the positioning information receiving unit 34 reaches the required number of responses (step S216). If it is judged that the number of pieces of target positioning information reaches the required number of responses (step S216; Yes), the process proceeds to step S218. If it is not judged that the number of pieces of target positioning information reaches the required number of responses (step S216; No), the process proceeds to step S210.

[0152] The process of step S218 is the same as the process of step S36 shown in FIG. 8, and therefore a description thereof will be omitted.

[0153] [Variations of superior information] (First Modification) The superiority information according to the first modified example of the fifth embodiment will be described with reference to Fig. 20. Fig. 20 is a diagram for explaining the superiority information according to the first modified example of the fifth embodiment. In Fig. 20, the horizontal axis indicates the distance on a plane, and the vertical axis indicates the altitude.

[0154] In the first modified example of the fifth embodiment, information on the altitude of the terminal device 12 may be used as the superior information. In the example shown in FIG. 20, the terminal device 12-1, the terminal device 12-2, and the target terminal device 14 are shown. The terminal device 12-1 is located at the same altitude as the target terminal device 14. The terminal device 12-2 is located at a higher position than the target terminal device 14. The arc 201 indicates a position where the received radio wave strength of the signal received from the target terminal device 14 is the same. The received radio wave strength of the signal received by the terminal device 12-1 and the terminal device 12-2 from the target terminal device 14 is the same. However, even if the received radio wave strength of the signal received from the target terminal device 14 is the same, the distance on the plane to the target terminal device 14 may differ. In the example shown in FIG. 20, the distance L2 between the target terminal device 14 and the terminal device 12-2 is shorter than the distance L1 between the target terminal device 14 and the terminal device 12-1.

[0155] It is assumed that it may be preferable for the management device 10 to calculate the position of the target terminal device 14 based on the target positioning information from the terminal device 12 located in the same altitude band as the target terminal device 14. Here, the position of the target terminal device 14 is set to an altitude of 0 m. For example, when the altitude is 0 m to 30 m, the time setting unit 86 sets the waiting time to "small". For example, when the altitude is 31 m to 60 m, the time setting unit 86 sets the waiting time to "medium". For example, when the altitude is 61 m or more, the time setting unit 86 sets the waiting time to "large". That is, the time setting unit 86 sets the waiting time to be shorter as the altitude is closer to the target terminal device 14, and sets the waiting time to be longer as the altitude is farther from the target terminal device 14. This allows the management device 10 to accurately calculate the position of the target terminal device 14 based on the target positioning information from the terminal device 12 located at the same altitude as the target terminal device 14. Note that, although the waiting time is set to three stages according to the altitude, the present invention is not limited to this. For example, the time setting unit 86 may set the waiting time in three or more stages by narrowing the range of altitudes for setting the waiting time, or may set the waiting time continuously according to the altitude. This makes it possible to prevent the timings of transmitting target positioning information from overlapping among a plurality of terminal devices 12.

[0156] (Second Modification) The superiority information according to the second modified example of the fifth embodiment will be described. In the present invention, the terminal device 12 calculates the position of the terminal device 12 based on the GNSS signal received by the GNSS receiver 72. The GNSS receiver 72 may determine the radio wave intensity of the received GNSS signal. If the radio wave intensity of the GNSS signal is weak, it may be that the terminal device 12 is located indoors, in an area where tall buildings such as high-rise buildings are densely packed, or in an area where trees are densely packed. If the received radio wave intensity of the GNSS signal is weak, the terminal device 12 may not be able to properly calculate the position. Therefore, in the modified example of the fifth embodiment, the superiority information is set based on the received radio wave intensity of the GNSS signal.

[0157] For example, when the received radio wave strength of the GNSS signal is -70 [dBm] or more (strong radio wave strength), the time setting unit 86 sets the waiting time to "small". For example, when the received radio wave strength of the GNSS signal is -90 [dBm] to -70 [dBm] (medium radio wave strength), the time setting unit 86 sets the waiting time to "medium". For example, when the received radio wave strength of the GNSS signal is -130 [dBm] to -90 [dBm] (weak radio wave strength), the time setting unit 86 sets the waiting time to "large". For example, when the received radio wave strength of the GNSS signal is -130 [dBm] or less (very weak radio wave strength), the time setting unit 86 sets the waiting time not to respond. That is, the stronger the received radio wave strength of the GNSS signal is, the shorter the waiting time is set, and the weaker the received radio wave strength of the GNSS signal is, the longer the waiting time is set. As a result, the management device 10 can accurately calculate the position of the target terminal device 14 based on the target positioning information from the terminal device 12 with strong received radio wave strength of the GNSS signal. Although the waiting time is set to three stages and no response according to the strength of the GNSS signal, the present invention is not limited to this. For example, the time setting unit 86 may set the waiting time to three or more stages by narrowing the width of the received radio wave strength of the GNSS signal for setting the waiting time, or may set the waiting time continuously according to the received radio wave strength of the GNSS signal. This makes it possible to prevent the timing of transmitting the target positioning information from overlapping between multiple terminal devices 12.

[0158] (Third Modification) A third modified example of the superiority information according to the fifth embodiment will be described with reference to Fig. 21. Fig. 21 is a diagram for explaining a third modified example of the superiority information according to the fifth embodiment. In Fig. 21, the horizontal axis indicates time, and the vertical axis indicates the received radio wave intensity of the GNSS signal.

[0159] In a third modified example of the fifth embodiment, the superiority information may be set based on the transition of the received radio wave strength of the GNSS signal. FIG. 21 shows the transition of the received radio wave strength of the GNSS signal from 60 minutes ago to the present. The area between the line 202 and the line 203 shows a range of about 20 [dBm]. Each point shown in FIG. 21 shows the measured received radio wave strength of the GNSS signal. For example, even if the radio wave strength is from -90 [dBm] to -70 [dBm] (medium radio wave strength), the received radio wave strength of the signal from the target terminal device 14 may be attenuated in the terminal device 12 located indoors. In this case, the management device 10 may not be able to accurately calculate the position of the target terminal device 14. Therefore, in the third modified example of the fifth embodiment, the superiority information is set according to the transition of the received radio wave strength of the GNSS signal.

[0160] For example, if the received radio wave strength of the GNSS signal does not change within a predetermined time, the time setting unit 86 sets the waiting time to "small". The predetermined time is, for example, 60 minutes, but is not limited to this. For example, if the received radio wave strength of the GNSS signal becomes weaker than a predetermined value within a predetermined time, the time setting unit 86 sets the waiting time to "medium". The change in the received radio wave strength of the GNSS signal that is determined to be weaker than the predetermined value is, for example, 20 [dBm], but is not limited to this. That is, the time setting unit 86 sets the waiting time to be short when the received radio wave strength of the GNSS signal does not change, and sets the waiting time to be long when the received radio wave strength of the GNSS signal becomes weaker than the predetermined value. As a result, the management device 10 can accurately calculate the position of the target terminal device 14 based on the target positioning information from the terminal device 12 in which the received radio wave strength of the GNSS signal does not change.

[0161] (Terminal device processing) The processing contents between the target terminal device and the terminal device according to the fifth embodiment will be described with reference to Fig. 22. Fig. 22 is a flowchart showing the processing contents between the target terminal device and the terminal device according to the fifth embodiment.

[0162] The target terminal device 14 determines whether or not a location information request signal has been received from the management device 10 (step S230). If it is determined that a location information request signal has been received (step S230; Yes), the process proceeds to step S232. If it is determined that a location information request signal has not been received (step S230; No), the process proceeds to step S234.

[0163] If it is determined as Yes in step S230, the target terminal device 14 executes a location information request process (step S232). The location information request process according to the fifth embodiment will be described with reference to Fig. 23. Fig. 23 is a flowchart showing the location information request process according to the fifth embodiment.

[0164] The target terminal device 14 determines whether or not the location information can be measured (step S240). If it is determined that the location information can be measured (step S240; Yes), the process proceeds to step S242. If it is not determined that the location information can be measured (step S240; No), the process proceeds to step S244.

[0165] If the result of the determination in step S240 is Yes, the target terminal device 14 measures the location information and transmits the measured location information to the management device 10 (step S242). Then, the process in FIG. 23 ends.

[0166] If the result of the determination in step 240 is No, the target terminal device 14 transmits a positioning information request signal to the multiple terminal devices 12 (step S244), and then ends the processing in FIG.

[0167] Please refer to Fig. 22. If it is determined that the result of step S230 is No, the position measurement information receiving unit 82 of the terminal device 12 determines whether or not a position measurement information request signal has been received from the target terminal device 14. If it is determined that the position measurement information request signal has been received (step S234; Yes), the process proceeds to step S236. If it is determined that the position measurement information request signal has not been received (step S234; No), the process of Fig. 22 ends.

[0168] If it is determined as Yes in step S234, the terminal device 12 executes the positioning process (step S236). The positioning process according to the fifth embodiment will be described with reference to Fig. 24. Fig. 24 is a flowchart showing the positioning process according to the fifth embodiment.

[0169] The condition decision unit 84 measures the received radio wave intensity when it receives the positioning information request signal from the target terminal device 14 (step S250), and then proceeds to step S252.

[0170] The condition determination unit 84 determines whether the measured received radio wave strength satisfies the response condition set by the management device 10 (step S252). If it is determined that the received radio wave strength satisfies the response condition set by the management device 10 (step S252; Yes), the process proceeds to step S254. If it is determined that the received radio wave strength does not satisfy the response condition set by the management device 10 (step S252; No), the process of FIG. 24 ends.

[0171] If the answer to step S252 is Yes, the time setting unit 86 determines the response waiting time based on the priority information that is set in advance (step S254), and then the process proceeds to step S256.

[0172] The counting unit 88 starts counting the number of responses of target positioning information to the positioning information request signal (step S256), and then the process proceeds to step S258.

[0173] The control unit 74 waits until the response waiting time elapses (step S258), and then proceeds to step S260.

[0174] After waiting for the response waiting time, the response number determination unit 90 determines whether the number of responses of the target positioning information to the positioning information request signal satisfies the condition (step S260). Specifically, the response number determination unit 90 determines that the condition is satisfied when the number of responses of the target positioning information to the positioning information request signal does not reach a preset required number of responses. If it is determined that the number of responses of the target positioning information to the positioning information request signal satisfies the condition (step S260; Yes), the process proceeds to step S262. If it is not determined that the number of responses of the target positioning information to the positioning information request signal satisfies the condition (step S260; No), the process of FIG. 24 ends.

[0175] If the result of the determination in step S260 is Yes, the position detection unit 80 locates the position of the terminal device 12 (step S262). Specifically, the position detection unit 80 detects the current position of the terminal device 12 based on the GNSS signal received by the GNSS receiving unit 72. Then, the process proceeds to step S264.

[0176] The positioning information transmission unit 92 transmits the target positioning information, including the position information indicating the current position of the terminal device 12a and the received radio wave intensity measured by the condition determination unit 84, to the management device 10 via the communication unit 68. Then, the process of FIG. 24 ends.

[0177] As described above, the fifth embodiment calculates the position of the target terminal device 14 based on the target positioning information transmitted by the terminal device 12 according to the predetermined response required number and superiority information. As a result, the fifth embodiment can reduce the amount of communication between the management device 10 and the terminal device 12 and properly calculate the position of the target terminal device 14.

[0178] [Sixth embodiment] A sixth embodiment will be described. In the sixth embodiment, the response conditions are that the received radio wave intensity is equal to or greater than a threshold and that the number of responses required is a predetermined number. In the sixth embodiment, the process related to the superiority information in the fifth embodiment may be omitted.

[0179] (Location information calculation process) A location information calculation process in the communication system according to the sixth embodiment will be described with reference to Fig. 25. Fig. 25 is a sequence diagram showing the flow of location information calculation process in the communication system according to the sixth embodiment.

[0180] The processes from step S270 to step S274 are the same as the processes from step S180 to step S184 shown in FIG. 18, respectively, and therefore will not be described.

[0181] The processes in steps S276a and S278a are the same as those in steps S186a and S190a shown in FIG. 18, respectively, and therefore will not be described.

[0182] The processes in steps S276b and S278b are the same as those in steps S186b and S190b shown in FIG. 18, respectively, and therefore will not be described.

[0183] The processes in steps S276c and S278c are the same as those in steps S186 and S190c shown in FIG. 18, respectively, and therefore will not be described.

[0184] The response number determination unit 90 of the terminal device 12c determines the number of responses to the positioning information request signal (step S280c). Here, since the number of responses is "0", the response number determination unit 90 of the terminal device 12c determines that a response is possible.

[0185] The processes in steps S282c and S284c are the same as those in steps S196c and S198c shown in FIG. 18, respectively, and therefore will not be described.

[0186] The processes of steps S276d, S278d, S280d, S282d, and S284d are the same as the processes of steps S276c, S278c, S280c, S282c, and S284c, respectively, except that the subject is terminal device 12d, and therefore description thereof will be omitted. In step S280d, since the number of responses is "1", response number determination unit 90 of terminal device 12d determines that a response is possible.

[0187] The processes of steps S280b, S282b, and S284b are the same as the processes of steps S280c, S282c, and S284c, respectively, except that the subject is terminal device 12b, and therefore description thereof will be omitted. In step S280b, since the number of responses is "2", response number determination unit 90 of terminal device 12b determines that a response is possible.

[0188] The process in step S286 is the same as step S200 shown in FIG. 18, and therefore a description thereof will be omitted.

[0189] The process of step S280a is the same as the process of step S280c except that the subject is the terminal device 12a, so the explanation is omitted. In step S280a, since the number of responses is "3", the response number determination unit 90 of the terminal device 12a determines that a response is not possible. Therefore, the terminal device 12a does not transmit the target positioning information to the management device 10.

[0190] The positioning process according to the sixth embodiment will be described with reference to Fig. 26. Fig. 26 is a flowchart showing the positioning process according to the sixth embodiment. The processing contents of the target terminal device 14 and the terminal device 12 according to the sixth embodiment and the location information request process are the same as those in the fifth embodiment, and therefore the description thereof will be omitted.

[0191] The processes in steps S290 and S292 are the same as those in steps S250 and S256 shown in FIG. 24, respectively, and therefore will not be described.

[0192] The response number determination unit 90 determines whether the response number of the target positioning information to the positioning information request signal satisfies the condition (step S294). If it is determined that the response number of the target positioning information to the positioning information request signal satisfies the condition (step S294; Yes), the process proceeds to step S296. If it is not determined that the response number of the target positioning information to the positioning information request signal satisfies the condition (step S294; No), the process of FIG. 26 ends.

[0193] The processes in steps S296 and S298 are the same as those in steps S262 and S264 shown in FIG. 24, respectively, and therefore will not be described.

[0194] As described above, the sixth embodiment calculates the position of the target terminal device 14 based on the target positioning information transmitted by the terminal device 12 according to a predetermined required response number. This makes it possible to reduce the amount of communication between the management device 10 and the terminal device 12 in the sixth embodiment.

[0195] Each component of each device shown in the figure is a functional concept, and does not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit according to various loads, usage conditions, etc. This distribution and integration configuration may be performed dynamically.

[0196] Although the embodiments of the present invention have been described above, the present invention is not limited to the contents of these embodiments. The above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments. [Explanation of symbols]

[0197] 1. Communication Systems 10 Management device 12 Terminal Equipment 14 Target terminal device 20,68 Communications Department 22,70 Storage part 24,74 Control section 26,72 GNSS receiver 30 Location information request section 32 Condition determination section 34 Positioning information receiving unit 36 Position calculation section 38,82 Positioning information receiving unit 40,80 Position detection unit 42 Radio field strength determination section 84 Condition judgment section 86 Time setting section 88 Counting Section 90 Response number determination unit 92 Positioning information transmission unit

Claims

1. A communication unit that communicates with a target terminal device and a management device; A position detection unit that detects its own position information; a positioning request receiving unit that receives a positioning information request signal including a threshold value of received radio wave intensity and a required number of responses from the target terminal device via the communication unit; a condition determination unit that determines whether or not the received radio wave intensity when the positioning information request signal is received from the target terminal device is equal to or greater than the threshold; a time setting unit that has information related to superiority information and a response waiting time in advance, and when the condition determination unit determines that the received radio wave strength is equal to or greater than the threshold, sets and measures a response waiting time according to the received radio wave strength when the positioning information request signal is received and the superiority information; a counting unit that counts the number of responses of positioning information signals that are responses to the positioning information request signal intercepted by a communication unit; a response number determination unit that determines whether or not the number of responses counted by the count unit has reached the required response number after the response waiting time set by the time setting unit has elapsed; a positioning information transmitting unit configured to transmit, to a management device, target positioning information including the location information and the received radio wave intensity when the response number determining unit determines that the response number does not reach the required response number; and A terminal device comprising:

2. The superiority information is the received radio wave intensity, The superiority information held by the time setting unit is such that the stronger the received radio wave intensity is, the shorter the response waiting time is. The terminal device according to claim 1 .

3. the superior information is detection accuracy of the position information, The priority information held by the time setting unit is such that the higher the detection accuracy of the location information of the location detection unit, the shorter the response waiting time. The terminal device according to claim 1 .

4. Further, a battery remaining capacity detection unit is provided, The superior information is a remaining battery capacity, The superiority information held by the time setting unit is such that the greater the remaining battery charge, the shorter the response waiting time. The terminal device according to claim 1 .

5. Detecting its own location information; receiving a positioning information request signal including a threshold value of received radio wave intensity and a required number of responses from a target terminal device; a condition determination unit that determines whether or not the received radio wave intensity when the positioning information request signal is received from the target terminal device is equal to or greater than the threshold; a step of having information relating to superiority information and a response waiting time in advance, and when it is determined that the received radio wave strength is equal to or greater than the threshold, setting and measuring a response waiting time according to the received radio wave strength at the time of receiving the positioning information request signal and the superiority information; counting the number of responses of positioning information signals which are responses to the positioning information request signal; a step of determining whether or not the counted number of responses has reached the required number of responses after the response waiting time has elapsed; transmitting, to a management device, target positioning information including the location information and the received radio wave intensity when the positioning information request signal is received, when it is determined that the number of responses has not reached the required number of responses; A communication control method comprising:

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