Communication device and communication method

Abstract

To appropriately estimate the location information of a communication device. [Solution] A communication device includes a position information acquisition unit that periodically acquires position information from a position information signal, an acceleration information acquisition unit that acquires acceleration information indicating acceleration applied to the communication device itself, a memory unit that associates the position information acquired by the position information acquisition unit with the acceleration information acquired by the acceleration information acquisition unit and stores them as acceleration position information, and a calculation unit that calculates an estimated position of the communication device itself based on the acceleration position information stored in the memory unit. When a change in acceleration equal to or greater than a first threshold occurs in the communication device itself, the calculation unit calculates the estimated position of the communication device itself based on position information acquired after the change in acceleration equal to or greater than the first threshold occurs from the acceleration position information.

Description

[Technical Field]

[0001] The present disclosure relates to a communication device and a communication method. [Background technology]

[0002] A technology has been disclosed that detects a person's fall and notifies a third party of the fact of the fall and the position of the fall (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-252618 Summary of the Invention [Problem to be solved by the invention]

[0004] When calculating location information based on GNSS signals (location information signals) received from GNSS (Global Navigation Satellite System) satellites, the accuracy of location calculation deteriorates if the carrier-to-noise ratio (C / N), which is the ratio of carrier power to noise power density, is low. It is desirable to be able to estimate location information appropriately even when the C / N of the GNSS signal is poor.

[0005] An object of the present disclosure is to provide a communication device and a communication method that can appropriately estimate location information of the communication device itself. [Means for solving the problem]

[0006] The communication device of the present disclosure comprises a position information acquisition unit that periodically acquires position information from a position information signal; an acceleration information acquisition unit that acquires acceleration information indicating the acceleration applied to the communication device; a memory unit that associates the position information acquired by the position information acquisition unit with the acceleration information acquired by the acceleration information acquisition unit and stores them as acceleration position information; and a calculation unit that calculates an estimated position of the communication device based on the acceleration position information stored in the memory unit, wherein when a change in acceleration of greater than or equal to a first threshold occurs in the communication device, the calculation unit calculates the estimated position of the communication device based on the position information acquired from the acceleration position information after the change in acceleration of greater than or equal to the first threshold occurs.

[0007] The communication method disclosed herein includes the steps of periodically acquiring position information from a position information signal, acquiring acceleration information indicating the acceleration applied to the communication device, associating the acquired position information with the acquired acceleration information and storing them in a memory unit as acceleration position information, calculating an estimated position of the communication device based on the acceleration position information stored in the memory unit, and, when a change in acceleration of greater than or equal to a first threshold occurs in the communication device, calculating an estimated position of the communication device based on the position information acquired from the acceleration position information after the change in acceleration of greater than or equal to the first threshold occurs. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to appropriately estimate the location information of the communication device itself. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram for explaining an outline of processing performed by a communication device according to the first embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of the configuration of a communication device according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of acceleration position information according to the embodiment. [Figure 4]FIG. 4 is a diagram for explaining a method for calculating an estimated position of a communication device according to the embodiment. [Figure 5] FIG. 5 is a flowchart showing the flow of the process of calculating an estimated position according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing the flow of the process of calculating an estimated position according to the second embodiment. [Figure 7] FIG. 7 is a flowchart showing the flow of the estimated position calculation process according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to these embodiments, and in the following embodiments, the same components are designated by the same reference numerals, and redundant description will be omitted.

[0011] [First embodiment] (overview) An overview of the processing of the communication device according to the first embodiment will be described using Fig. 1. Fig. 1 is a diagram for explaining an overview of the processing of the communication device according to the first embodiment.

[0012] 1 shows an example in which communication device 10-1 and communication device 10-2 communicate with each other. When there is no need to distinguish between communication device 10-1 and communication device 10-2, they are collectively referred to as communication device 10. Communication device 10 is a portable communication device such as a commercial radio or a smartphone. Communication device 10-2 does not have to be portable.

[0013] In the following, an example of a method for acquiring the current position of communication device 10 will be described as acquiring the current position information from position information (GNSS information) included in a position information signal (GNSS signal) transmitted by a communication satellite (GNSS satellite), but the present disclosure is not limited to this. For example, when the user of communication device 10-1 falls, communication device 10-1 calculates current position information based on the GNSS signal received from GNSS satellite 12 and transmits the calculated position information to communication device 10-2.

[0014] However, if the C / N ratio when the GNSS signal is received is lower than a predetermined ratio, the communication device 10-1 will be unable to accurately calculate current location information. In this case, the communication device 10-1 will be unable to transmit correct location information to the communication device 10-2. Therefore, in the present disclosure, if the C / N ratio when the GNSS signal is received is lower than a predetermined ratio, the communication device 10-1 performs a process of accurately calculating a current estimated location based on the received GNSS signal.

[0015] (Communication equipment) An example of the configuration of a communication device according to an embodiment will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of the configuration of a communication device according to an embodiment.

[0016] As shown in FIG. 2, the communication device 10 includes an input unit 20, an output unit 22, an acceleration sensor 24, a GNSS receiver 26 (position information receiver), a communication unit 28, a storage unit 30, and a control unit 32.

[0017] The input unit 20 accepts various input operations for the communication device 10. The input unit 20 is configured with various input devices such as a touch panel, a button, a switch, and a microphone.

[0018] The output unit 22 is configured with an output device that outputs various types of information. The output unit 22 includes, for example, a display device such as a liquid crystal display, an organic EL (Electro-Luminescence) display, etc. The output unit 22 includes, for example, a speaker that outputs sound.

[0019] The acceleration sensor 24 detects acceleration occurring in the communication device 10. The acceleration sensor 24 outputs acceleration information indicating the detected acceleration to the acceleration information acquisition unit .

[0020] The GNSS receiving unit 26 is configured with a GNSS receiver that receives GNSS signals transmitted from GNSS satellites, etc. The GNSS receiving unit 26 outputs the received GNSS signals to the GNSS information acquiring unit 40.

[0021] The communication unit 28 is a communication interface that executes communication between the communication device 10 and an external device. The communication unit 28 executes communication between the communication device 10 and another communication device 10, for example.

[0022] The storage unit 30 stores various types of information. The storage unit 30 stores information such as the calculation contents of the control unit 32 and communication programs. The storage unit 30 includes at least one of a main storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory), and an external storage device such as an HDD (Hard Disk Drive).

[0023] The storage unit 30 stores acceleration GNSS information in which GNSS information is associated with acceleration information indicating acceleration occurring in the communication device 10. The acceleration GNSS information will be described later.

[0024] The control unit 32 controls each unit of the communication device 10. The control unit 32 includes, 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 32 executes a communication program that controls the operation of the communication device 10 according to the present disclosure. The control unit 32 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 32 may be realized by a combination of hardware and software.

[0025] The control unit 32 includes a GNSS information acquisition unit (position information acquisition unit) 40, an acceleration information acquisition unit 42, a signal determination unit 44, a memory control unit 46, a calculation unit 48, and an output unit 50.

[0026] The GNSS information acquisition unit 40 periodically acquires GNSS information from the GNSS signals acquired by the GNSS reception unit 26 .

[0027] The acceleration information acquisition unit 42 acquires acceleration information indicating the magnitude of acceleration occurring in the communication device 10. The acceleration information acquisition unit 42 acquires the acceleration information based on the detection result of the acceleration sensor 24.

[0028] The signal determination unit 44 determines the reception sensitivity of the GNSS signal received by the GNSS receiver 26. For example, the signal determination unit 44 determines whether the carrier-to-noise density ratio of the GNSS signal received by the GNSS receiver 26 is equal to or less than a predetermined value.

[0029] The storage control unit 46 stores various types of information in the storage unit 30. The storage control unit 46 associates the GNSS information acquired by the GNSS information acquisition unit 40 with the acceleration information acquired by the acceleration information acquisition unit 42, and stores the associated information in the storage unit 30 as acceleration GNSS information (acceleration position information).

[0030] The acceleration GNSS information according to the embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of the acceleration GNSS information according to the embodiment.

[0031] As shown in FIG. 3, the acceleration GNSS information D1 includes items such as "reception time," "acceleration," "data number," "latitude," and "longitude."

[0032] The "reception time" indicates the time when the GNSS receiver 26 receives the GNSS signal from the GNSS satellite. In the example shown in Fig. 3, the GNSS receiver 26 receives the GNSS signal from the GNSS satellite, and the GNSS information acquirer 40 acquires the GNSS information every second.

[0033] "Acceleration" is a type of acceleration information. "Acceleration" refers to the magnitude (m / s) of acceleration occurring in the communication device 10 when the GNSS information acquisition unit 40 acquires GNSS information. 2 )

[0034] "Data number," "latitude," and "longitude" are types of GNSS information.

[0035] "Data number" represents the number of the GNSS signal. "Latitude" represents the latitude of the communication device 10 when the GNSS receiver 26 receives the GNSS signal. "Longitude" represents the longitude of the communication device 10 when the GNSS receiver 26 receives the GNSS signal.

[0036] Although "latitude" and "longitude" are conceptually shown as "Lat1" and "Lon1", respectively, in reality, specific coordinates are shown.

[0037] The calculation unit 48 calculates position information indicating the current position of the communication device 10. The calculation unit 48 calculates the position information of the current position of the communication device 10 based on the GNSS signal received by the GNSS receiving unit 26 using a known method.

[0038] Specifically, when the GNSS receiver 26 receives a GNSS signal, if the carrier-to-noise density ratio of the GNSS signal exceeds a predetermined value, the calculation unit 48 calculates the location information of the current location of the communication device 10 based on the GNSS signal using a known method.

[0039] If the carrier-to-noise density ratio of the GNSS signal received by the GNSS receiver 26 is equal to or less than a predetermined value, the calculator 48 calculates the estimated position of the communication device 10. For example, the calculator 48 calculates the estimated position of the communication device 10 based on the acceleration GNSS information D1 stored in the storage unit 30. Specifically, if a change in acceleration equal to or greater than a predetermined first threshold occurs in the communication device 10, the calculator 48 calculates the estimated position of the communication device 10 based on GNSS information acquired from the acceleration GNSS information D1 after the change in acceleration equal to or greater than the first threshold occurs. In this case, the calculator 48 calculates the moving average of the GNSS information as the moving average of the communication device 10.

[0040] An acceleration equal to or greater than the first threshold value refers to an acceleration of a magnitude at which it is determined that the user of the communication device 10 has fallen. That is, the calculation unit 48 calculates the estimated position of the communication device 10 if the carrier-to-noise density ratio of the GNSS signal when the user of the communication device 10 has fallen is equal to or less than a predetermined value. Possible causes of the carrier-to-noise density ratio becoming equal to or less than the predetermined value after the user of the communication device 10 has fallen include entering an area with an obstacle in the zenith direction, falling so that an obstacle is on top of the communication device 10, or a malfunction of the GNSS receiving unit 26.

[0041] A method for calculating an estimated position of a communication device according to an embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining a method for calculating an estimated position of a communication device according to an embodiment.

[0042] 4, the horizontal axis represents the data number, and the vertical axis represents the magnitude of the acceleration occurring in the communication device 10. Fig. 4 is a graph showing the change over time in acceleration included in the acceleration GNSS information D1 shown in Fig. 3.

[0043] Line 101 represents a first threshold value for acceleration, for example, 5 m / s 2 However, the first threshold may be, for example, an acceleration of a magnitude that determines that the user of the communication device 10 has fallen. A line 102 represents a second threshold of acceleration that is smaller than the first threshold. The second threshold is, for example, 2 m / s 2 The second threshold may be, but is not limited to, an acceleration of a magnitude that determines that the user of the communication device 10 has started moving after falling. Examples of the user's movement after falling include, but are not limited to, slipping, falling, walking, crawling, etc. Line 103 represents the change in acceleration that has occurred in the communication device 10.

[0044] In the example shown in FIG. 4, in data number #2, the communication device 10 receives a 10.0 m / s 2 and an acceleration exceeding the first threshold occurs. In this case, the calculation unit 48 determines that the user of the communication device 10 fell at the time the GNSS information of data number #2 was acquired. The calculation unit 48 calculates a moving average of the "latitude" and "longitude" of the communication device 10 as an estimated position based on the "latitude" and "longitude" of data numbers #2 to #40.

[0045] Furthermore, if the communication device 10 experiences acceleration equal to or greater than the first threshold and then continues to experience a change in acceleration equal to or greater than the second threshold, the calculation unit 48 may calculate the estimated location of the communication device 10 based on the GNSS information for the section of the acceleration GNSS information D1 where the change in acceleration equal to or greater than the second threshold continues. In the example shown in FIG. 4 , the calculation unit 48 determines, for example, that the user of the communication device 10 stood up when the GNSS information of data number #14 was acquired and began to move after the GNSS information of data number #17 was acquired. The calculation unit 48 calculates the moving average of the "latitude" and "longitude" of the communication device 10 as the estimated location based on the "latitude" and "longitude" of data numbers #17 to #40. That is, the calculation unit 48 calculates the estimated location of the communication device 10 by excluding the "latitude" and "longitude" of data numbers #3 to #16, which were acquired while the user of the communication device 10 was stationary. By calculating the moving average while excluding the "latitude" and "longitude" while the user of the communication device 10 is stationary, the estimation accuracy can be improved.

[0046] (Estimated position calculation process) The process of calculating an estimated position according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing the flow of the process of calculating an estimated position according to the first embodiment.

[0047] The GNSS information acquisition unit 40 periodically acquires GNSS information from the GNSS signal received by the GNSS reception unit 26 (step S10).

[0048] The acceleration information acquisition unit 42 periodically acquires acceleration information occurring in the communication device 10 from the detection result detected by the acceleration sensor 24 (step S12).

[0049] The storage control unit 46 stores acceleration GNSS information in which the GNSS information acquired by the GNSS information acquisition unit 40 and the acceleration information acquired by the acceleration information acquisition unit 42 are associated with each other in the storage unit 30 (step S14). The processes from step S10 to step S14 are periodically repeated.

[0050] The calculation unit 48 determines whether a change in acceleration equal to or greater than the first threshold has occurred in the communication device 10 (step S16). Specifically, the calculation unit 48 determines whether a change in acceleration equal to or greater than the first threshold has occurred in the communication device 10, based on the acceleration information acquired by the acceleration information acquisition unit 42. If it is determined that a change in acceleration equal to or greater than the first threshold has occurred in the communication device 10 (step S16; Yes), the process proceeds to step S18. If it is determined that a change in acceleration equal to or greater than the first threshold has not occurred in the communication device 10 (step S16; No), the process proceeds to step S28.

[0051] If the determination in step S16 is Yes, the signal determination unit 44 determines whether the carrier-to-noise density ratio when the GNSS receiver 26 receives the GNSS signal is equal to or less than a predetermined value (step S18). Specifically, when a change in acceleration equal to or greater than a first threshold occurs in the communication device 10, the signal determination unit 44 determines whether the carrier-to-noise density ratio when the GNSS receiver 26 receives the GNSS signal is equal to or less than a predetermined value. If it is determined that the carrier-to-noise density ratio is equal to or less than the predetermined value (step S18; Yes), the process proceeds to step S22. If it is determined that the carrier-to-noise density ratio exceeds the predetermined value (step S18; No), the process proceeds to step S20.

[0052] If the determination in step S18 is No, the calculation unit 48 calculates the current position of the communication device 10 by a known method based on the GNSS signal received by the GNSS receiving unit 26 (step S20), and then proceeds to step S28.

[0053] If the answer is Yes in step S18, the calculation unit 48 selects the acceleration GNSS information stored in the memory unit 30 after an acceleration greater than or equal to the first threshold has occurred in order to calculate the estimated position of the communication device 10 (step S22).

[0054] The calculation unit 48 calculates an estimated position of the communication device 10 based on the GNSS information obtained after the communication device 10 has experienced acceleration equal to or greater than the first threshold (step S24).

[0055] The output unit 50 transmits the calculated estimated position to the other communication device 10 via the communication unit 28 (step S26).

[0056] The control unit 32 determines whether or not to end the process (step S28). For example, the control unit 32 determines to end the process when an operation to turn off the power of the communication device 10 is received. If it is determined to end the process (step S28; Yes), the process of FIG. 5 ends. If it is determined not to end the process (step S28; No), the process proceeds to step S10.

[0057] As described above, in the first embodiment, if the carrier-to-noise density ratio of the GNSS signal when the user of the communication device falls is equal to or less than a predetermined value, the current position of the user is calculated based on GNSS information acquired after the fall. As a result, the first embodiment can accurately estimate the current position even when the carrier-to-noise density ratio of the GNSS signal is equal to or less than a predetermined value.

[0058] [Second embodiment] (Estimated position calculation process) The process of calculating an estimated position according to the second embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the flow of the process of calculating an estimated position according to the second embodiment.

[0059] The processing from step S40 to step S48 is the same as the processing from step S10 to step S18 shown in FIG. 5, and therefore a description thereof will be omitted.

[0060] If the determination in step S48 is Yes, the calculation unit 48 determines whether or not the communication device 10 is continuously experiencing acceleration equal to or greater than the second threshold (step S52). If it is determined that the communication device 10 is continuously experiencing acceleration equal to or greater than the second threshold (step S52; Yes), the calculation unit 48 proceeds to step S56. If it is determined that the communication device 10 is not continuously experiencing acceleration equal to or greater than the second threshold (step S52; No), the calculation unit 48 proceeds to step S54.

[0061] The process in step S54 is the same as the process in step S22 shown in FIG. 5, and therefore a description thereof will be omitted.

[0062] If the answer to step S52 is Yes, the calculation unit 48 selects, from the acceleration GNSS information stored in the memory unit 30, GNSS information acquired in a section where acceleration equal to or greater than the first threshold occurs and then continues to occur equal to or greater than the second threshold, in order to calculate the estimated position of the communication device 10 (step S56).

[0063] The calculation unit 48 calculates an estimated position of the communication device 10 based on the GNSS information acquired during a period in which acceleration equal to or greater than the second threshold continues after acceleration equal to or greater than the first threshold occurs in the communication device 10 (step S58).

[0064] The processes in steps S60 and S62 are the same as those in steps S26 and S28 shown in FIG. 5, respectively, and therefore will not be described further.

[0065] As described above, in the second embodiment, if the carrier-to-noise density ratio of the GNSS signal when the user of the communication device falls is equal to or less than a predetermined value, the current position of the user is calculated based on the GNSS information for the section in which acceleration equal to or greater than a predetermined value continues to occur after the fall. As a result, in the second embodiment, when the carrier-to-noise density ratio of the GNSS signal is equal to or less than a predetermined value, the estimation accuracy can be improved by estimating position information by excluding the GNSS information for the section in which the user is stopped.

[0066] [Third embodiment] (Estimated position calculation process) The process of calculating an estimated position according to the third embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing the flow of the process of calculating an estimated position according to the third embodiment.

[0067] The processing from step S70 to step S78 is the same as the processing from step S10 to step S18 shown in FIG. 5, and therefore a description thereof will be omitted.

[0068] If the determination in step S78 is Yes, the calculation unit 48 determines whether the acceleration occurring in the communication device 10 is zero for a predetermined period or longer (step S82). In other words, the calculation unit 48 determines whether the user of the communication device 10 has remained stationary for a predetermined period or longer after falling. If it is determined that the acceleration occurring in the communication device 10 is zero for a predetermined period or longer (step S82; Yes), the process proceeds to step S86. If it is determined that the acceleration occurring in the communication device 10 is not zero for a predetermined period or longer (step S82; No), the process proceeds to step S84.

[0069] The process in step S84 is the same as the process in step S22 shown in FIG. 5, and therefore a description thereof will be omitted.

[0070] If the answer to step S82 is Yes, the calculation unit 48 selects, from the acceleration GNSS information stored in the memory unit 30, GNSS information acquired in a section where acceleration is zero after acceleration equal to or greater than the first threshold occurs, in order to calculate the estimated position of the communication device 10 (step S86).

[0071] After the communication device 10 experiences acceleration equal to or greater than the first threshold, the calculation unit 48 calculates an estimated position of the communication device 10 based on the GNSS information acquired during a period in which the acceleration is zero (step S88).

[0072] The processes in steps S90 and S92 are the same as those in steps S26 and S28 shown in FIG. 5, respectively, and therefore will not be described further.

[0073] As described above, in the third embodiment, if the carrier-to-noise density ratio of the GNSS signal when the user of the communication device falls is equal to or less than a predetermined value and the acceleration remains at zero after the fall, the current position of the user is calculated based on the GNSS information for the period in which the acceleration is zero. As a result, the third embodiment can accurately estimate the position information of the location where the user is stopped when the carrier-to-noise density ratio of the GNSS signal is equal to or less than a predetermined value.

[0074] The components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown. 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 depending on various loads and usage conditions. This distribution and integration configuration may also be performed dynamically.

[0075] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the contents of these embodiments. Furthermore, 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 combined as appropriate. 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]

[0076] 10, 10-1, 10-2 Communication equipment 20 Input section 22,50 Output section 24 Acceleration sensor 26 GNSS receiver 28 Communications Department 30 Storage section 32 Control Unit 40 GNSS information acquisition section 42 Acceleration information acquisition section 44 Signal determination unit 46 Memory control unit 48 Calculation Unit

Claims

1. a location information acquisition unit that periodically acquires location information from a location information signal; an acceleration information acquisition unit that acquires acceleration information indicating acceleration applied to the communication device; a storage unit that associates the position information acquired by the position information acquisition unit with the acceleration information acquired by the acceleration information acquisition unit and stores the information as acceleration position information; a calculation unit that calculates an estimated position of the communication device based on the acceleration position information stored in the storage unit; Equipped with When a change in acceleration equal to or greater than a first threshold occurs in the communication device, the calculation unit calculates an estimated position of the communication device based on the position information acquired after the change in acceleration equal to or greater than the first threshold occurs from the acceleration position information. Communication equipment.

2. When a change in acceleration equal to or greater than a second threshold value that is smaller than the first threshold value continues in the communication device, the calculation unit calculates an estimated position of the communication device based on the position information of a section in which a change in acceleration equal to or greater than the second threshold value occurs from the acceleration position information. The communication device according to claim 1 .

3. the calculation unit calculates an estimated position of the communication device based on a moving average of the position information.

3. The communication device according to claim 1 or 2.

4. the calculation unit calculates an estimated position of the communication device when a carrier-to-noise density ratio of the position information signal is equal to or less than a predetermined value when a change in acceleration equal to or greater than the first threshold occurs in the communication device; 3. The communication device according to claim 1 or 2.

5. periodically acquiring location information from a location information signal; acquiring acceleration information indicating an acceleration applied to the communication device; a step of storing the acquired position information and the acquired acceleration information in a storage unit in association with each other as acceleration position information; calculating an estimated position of the communication device based on the acceleration position information stored in the storage unit; When a change in acceleration equal to or greater than a first threshold occurs in the communication device, calculating an estimated position of the communication device based on the position information acquired after the change in acceleration equal to or greater than the first threshold occurs from the acceleration position information; A communication method, including:

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