Information transmission method and information processing method

Abstract

To provide an information transmission method or the like capable of transmitting information which can identify the location of a reflection object for reflecting a radio wave of a transmission station such as a broadcasting station.SOLUTION: An information transmission method of a mobile reception terminal which can receive a direct wave of a radio wave and a reflection wave of the radio wave transmitted from a transmission station whose location is fixed and which always or periodically transmits radio waves of the same modulation system and can be connected to a server through a network, includes: a creation step (S10) of creating a delay profile showing a time difference between the direct wave and the reflection wave as of when the direct wave and the reflection wave are received, and an upload step (S11) of transmitting the created delay profile to the server through the network.SELECTED DRAWING: Figure 16

Description

[Technical field]

[0001] The present disclosure relates to an information transmitting method, an information processing method, and a mobile receiving terminal. [Background technology]

[0002] A technique has been proposed for estimating the amount of water vapor on the propagation path of radio waves using terrestrial digital broadcasting waves (for example, Non-Patent Document 1).

[0003] According to non-patent document 1, by having a receiving terminal receive radio waves that arrive directly from a broadcasting station (direct waves) and waves that are reflected from, for example, a building, the amount of water vapor along the path taken by the reflected waves can be estimated from the reception information of the direct waves and reflected waves at the receiving terminal. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] S. Kawamura, H. Ohta, H. Hanado, MK Yamamoto, N. Shiga, K. Kido, S. Yasuda, T. Goto,R. Ichikawa, J. Amagai, K. Imamura , M. Fujieda, H. Iwai, S. Sugitani, and T. Iguchi “Water vapor estimation using digital terrestrial broadcasting waves,”Radio Science,Volume52, Issue3 March 2017 Pages 367-377 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology disclosed in Non-Patent Document 1, the positions of the broadcasting station that transmits the terrestrial digital broadcasting wave, the receiving terminal, and the building that reflects the wave (reflecting object) must be fixed. Therefore, the propagation path that can estimate the amount of water vapor is also limited, and as a result, there is a problem that the area where the amount of water vapor can be measured is limited.

[0006] On the other hand, if the receiving terminal is mounted on a vehicle and moved, the position of the reflecting object that reflects the radio wave is no longer fixed, and the positional relationship between the reflecting object, the receiving terminal, and the broadcast station is no longer fixed. In addition, the technology disclosed in Non-Patent Document 1 cannot estimate the amount of water vapor because it cannot identify the position of the reflecting object.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide an information transmission method and a mobile receiving terminal capable of transmitting information capable of identifying the position of a reflecting object that reflects radio waves from a transmitting station such as a broadcasting station, etc. Furthermore, an object of the present disclosure is to provide an information processing method capable of identifying the position of a reflecting object that reflects radio waves from a transmitting station such as a broadcasting station even when a mobile receiving terminal is used, and capable of estimating the amount of water vapor. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, an information transmission method according to one embodiment of the present disclosure is an information transmission method for a mobile receiving terminal that has a fixed location, is capable of receiving direct waves and reflected waves of radio waves transmitted by a transmitting station that constantly or periodically transmits radio waves using the same modulation method, and is capable of connecting to a server via a network, and includes a creation step of creating a delay profile that indicates the time difference between the direct wave and the reflected wave when the direct wave and the reflected wave are received, and an upload step of transmitting the delay profile to the server via the network.

[0009] In order to achieve the above-mentioned objective, a mobile receiving terminal according to one embodiment of the present disclosure is a mobile receiving terminal that has a fixed location, is capable of receiving direct waves and reflected waves of radio waves transmitted by a transmitting station that constantly or periodically transmits radio waves using the same modulation method, and is capable of connecting to a server via a network, and is equipped with a processor and a memory, and the processor uses the memory to create a delay profile indicating the time difference between the direct wave and the reflected wave when they are received, and transmits the delay profile to the server via the network.

[0010] In addition, in order to achieve the above-mentioned object, an information transmission method according to one embodiment of the present disclosure is an information processing method of a server that can be connected via a network to a plurality of mobile receiving terminals whose location is fixed and that can receive direct waves of radio waves and reflected waves of the radio waves transmitted by a transmitting station that constantly or periodically transmits radio waves using the same modulation method, and includes an information acquisition step of acquiring from each of the plurality of mobile receiving terminals information regarding the current location of the mobile receiving terminal when the mobile receiving terminal receives the direct waves and the reflected waves, and a delay profile indicating the arrival time difference between the direct waves and the reflected waves, and a position identification step of deriving an elliptic curve on which a reflecting object that reflects the reflected waves may exist from each of the acquired delay profiles and information regarding the current location of the mobile receiving terminal, calculating an intersection between the plurality of elliptic curves obtained in relation to the plurality of delay profiles, and identifying the intersection as the position of the reflecting object if two or more of the elliptic curves intersect only at that intersection.

[0011] It should be noted that these general or specific aspects may be realized as an apparatus, a system, or an integrated circuit, or may be realized as any combination of a system, a method, an integrated circuit, and a computer program. Effect of the Invention

[0012] According to the information transmission method and the like of the present disclosure, it is possible to transmit information that can identify the position of a reflecting object that reflects radio waves from a transmitting station such as a broadcasting station. Furthermore, according to the information processing method of the present disclosure, even when a mobile receiving terminal is used, it is possible to identify the position of a reflecting object that reflects radio waves from a transmitting station such as a broadcasting station, and to estimate the amount of water vapor. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating an example of an entire system according to an embodiment. [Figure 2A] FIG. 2A is a block diagram showing an example of the configuration of the moving object shown in FIG. [Figure 2B] FIG. 2B is another example of the moving object shown in FIG. [Diagram 3] FIG. 3 is a block diagram illustrating an example of a configuration of a receiving terminal according to an embodiment. [Figure 4] FIG. 4 is a block diagram illustrating an example of a functional configuration of the arithmetic processing unit illustrated in FIG. [Diagram 5] FIG. 5 is a diagram for explaining the concept of a delay profile according to the embodiment. [Figure 6] FIG. 6 is a diagram for explaining an image of multipath. [Figure 7] FIG. 7 is a diagram conceptually illustrating an example of a delay profile caused by the multipath illustrated in FIG. [Figure 8A] FIG. 8A is a diagram conceptually showing OFDM subcarriers adopted in terrestrial digital broadcasting. [Figure 8B] FIG. 8B is a diagram conceptually showing an SP signal inserted into the radio waves of a digital terrestrial broadcast. [Figure 9] FIG. 9 is a block diagram illustrating an example of a configuration of a server according to the embodiment. [Figure 10] FIG. 10 is a block diagram illustrating an example of a functional configuration of the arithmetic processing unit illustrated in FIG. [Figure 11A] FIG. 11A is a diagram for explaining a method for identifying the position of a reflecting object from a plurality of delay profiles according to the embodiment. [Figure 11B] FIG. 11B is a diagram for explaining a method for identifying the position of a reflecting object from a plurality of delay profiles according to the embodiment. [Figure 12] FIG. 12 is a diagram showing an example of a map in which the positions of a plurality of reflecting objects in a predetermined area are mapped according to the embodiment. [Figure 13] FIG. 13 is a diagram for conceptually explaining the process for estimating the water vapor amount according to the embodiment. [Figure 14] FIG. 14 is a diagram for conceptually explaining a delay profile acquisition process for performing water vapor amount estimation according to the embodiment. [Figure 15A] FIG. 15A is a diagram showing the change in propagation delay of radio waves versus relative humidity at 1 atmospheric pressure and 20° C. [Figure 15B] FIG. 15B is a diagram showing a configuration for measuring the propagation delay of radio waves according to a comparative example. [Figure 16] FIG. 16 is a flowchart illustrating an example of the operation of the receiving terminal according to the embodiment. [Figure 17] FIG. 17 is a flowchart illustrating an example of the operation of the server according to the embodiment. [Figure 18] FIG. 18 is a flowchart showing detailed processing of step S22 in FIG. [Figure 19] FIG. 19 is a flowchart illustrating an example of an operation of estimating a water vapor amount by the server according to the embodiment. [Figure 20] FIG. 20 is a flowchart illustrating an example of the operation of the receiving terminal when water vapor amount estimation is performed according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An information transmission method according to one embodiment of the present disclosure is an information transmission method for a mobile receiving terminal that has a fixed location, is capable of receiving direct waves and reflected waves of radio waves transmitted by a transmitting station that constantly or periodically transmits radio waves using the same modulation method, and is capable of connecting to a server via a network, and includes a creation step of creating a delay profile that indicates the time difference between the direct waves and the reflected waves when the direct waves and the reflected waves are received, and an upload step of transmitting the delay profile to the server via the network.

[0015] This makes it possible to transmit information that can identify the position of a reflecting object that reflects radio waves from a transmitting station such as a broadcasting station.

[0016] Here, the delay profile is used by the server to calculate the distance between the mobile receiving terminal and the reflecting object that reflected the reflected wave from the time difference.

[0017] Moreover, in the information transmission method, the uploading step may be performed at predetermined time intervals.

[0018] Here, for example, the information transmission method further includes a location determination step of determining the location of the mobile receiving terminal when the direct wave and the reflected wave are received, and in the upload step, information regarding the determined location and information regarding the time when the direct wave and the reflected wave were received are transmitted to the server together with the delay profile.

[0019] Also, for example, the information transmission method may further include an acquisition step of acquiring instruction information including a receiving area of ​​the direct wave and the reflected wave from the server, a determination step of determining whether the position identified in the position identification step is included in the receiving area included in the instruction information, and a radio wave receiving step of receiving the direct wave and the reflected wave if it is determined in the determination step that the position is included in the receiving area, and in the creation step, the delay profile when the direct wave and the reflected wave received in the radio wave receiving step are received may be created.

[0020] Also, for example, the information transmission method may further include an acquisition step of acquiring instruction information including a receiving area of ​​the direct wave and the reflected wave from the server, and a position estimation step of estimating a future position which is a position within a predetermined time from the current position of the mobile receiving terminal, a future position determination step of determining whether the future position estimated in the position estimation step is located in the receiving area included in the instruction information, and a radio wave receiving step of receiving the direct wave and the reflected wave when the current position of the mobile receiving terminal is included in the receiving area if it is determined in the future position determination step that the future position is located in the receiving area, and in the creation step, the delay profile when the direct wave and the reflected wave received in the radio wave receiving step are received may be created.

[0021] Here, for example, the transmitting station transmits the same radio wave using an OFDM (Orthogonal Frequency Division Multiplexing) method.

[0022] An information processing method according to one embodiment of the present disclosure is an information processing method of a server that has a fixed location and can be connected via a network to a plurality of mobile receiving terminals that can receive direct waves of radio waves transmitted by a transmitting station that constantly or periodically transmits radio waves using the same modulation method, the information processing method including: an information acquisition step of acquiring, from each of the plurality of mobile receiving terminals, information regarding the current location of the mobile receiving terminal when the mobile receiving terminal received the direct waves and the reflected waves, and a delay profile indicating the arrival time difference between the direct waves and the reflected waves; and a position identification step of deriving an elliptic curve on which a reflecting object that reflected the reflected waves may exist from each of the acquired delay profiles and information regarding the current location of the mobile receiving terminal, calculating an intersection between the plurality of elliptic curves obtained in relation to the plurality of delay profiles, and identifying the intersection as the position of the reflecting object if two or more of the elliptic curves intersect only at that intersection.

[0023] This makes it possible to identify the position of a reflecting object that reflects radio waves from a transmitting station such as a broadcasting station.

[0024] Here, for example, in the information acquisition step, information relating to the time at the current location when the mobile receiving terminal received the direct wave and the reflected wave is acquired together with the delay profile.

[0025] Also, for example, the position identification step may further identify the positions of a plurality of the reflecting objects that are different from one another, and the information processing method may further include a map creation step of creating a map in which the positions of the plurality of the reflecting objects are mapped for each specified area.

[0026] Also, for example, the information processing method may further include a target area determination step of determining a target area, a reflecting object selection step of selecting a reflecting object in a specified area including the target area using the map created in the map creation step, a determination step of determining an area obtained by extending a straight line connecting the position of the one reflecting object and the target area as a receiving area, an area information acquisition step of acquiring, from one or more mobile receiving terminals at positions included in the receiving area, a delay profile when the mobile receiving terminal receives the direct wave and the reflected wave, and an estimation step of estimating the amount of water vapor in the target area using the delay profile acquired in the area information acquisition step.

[0027] This makes it possible to identify the position of an object that reflects radio waves from a transmitting station such as a broadcasting station, even when a mobile receiving terminal is used, and to estimate the amount of water vapor.

[0028] In addition, a mobile receiving terminal according to one embodiment of the present disclosure is a mobile receiving terminal that has a fixed location, is capable of receiving direct waves and reflected waves of radio waves transmitted by a transmitting station that constantly or periodically transmits radio waves using the same modulation method, and is capable of connecting to a server via a network, and is equipped with a processor and a memory, and the processor uses the memory to create a delay profile indicating the time difference between the direct waves and the reflected waves when they are received, and transmits the delay profile to the server via the network.

[0029] This makes it possible to transmit information that can identify the position of a reflecting object that reflects radio waves from a transmitting station such as a broadcasting station.

[0030] Each of the embodiments described below shows a specific example of the present disclosure. The numerical values, shapes, components, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components according to the following embodiments, those components that are not described in an independent claim showing a top concept are described as optional components. Furthermore, in all of the embodiments, the respective contents can be combined.

[0031] (Embodiment) Hereinafter, an embodiment will be described with reference to the drawings.

[0032] [1. Overall system] FIG. 1 is a diagram showing an example of an entire system according to the present embodiment.

[0033] In this embodiment, the overall system, as shown in FIG. 1, comprises a mobile body 10, a transmitting station 20 that constantly or periodically transmits radio waves using the same modulation method, a reflecting object 30 that reflects direct waves of the radio waves transmitted by the transmitting station 20, and a server 40.

[0034] First, the moving body 10 will be described.

[0035] [1.1 Mobile 10] Fig. 2A is a block diagram showing an example of the configuration of the moving object 10 shown in Fig. 1. Fig. 2B is another example of the moving object 10 shown in Fig. 1.

[0036] The moving body 10 is, for example, a vehicle such as an automobile, and includes a receiving terminal 11 and a drive unit 12, for example, as shown in Fig. 2A. The moving body 10 may have the receiving terminal 11 mounted therein, for example by incorporating the functions of the receiving terminal 11 into a car navigation system. The moving body 10 may also have the receiving terminal 11 mounted externally, for example by placing the receiving terminal 11 on a loading platform as shown in Fig. 2B. The moving body 10 may be a dolly on which the receiving terminal 11 can be mounted, as long as the moving body 10 can move with the receiving terminal 11 mounted thereon.

[0037] [1.1.1 Drive unit 12] The driving unit 12 is a functional unit that performs control for the movement of the moving body 10, and if the moving body 10 is an automobile, performs general control for operating the automobile.

[0038] [1.1.2 Receiving terminal 11] The receiving terminal 11 is an example of a mobile receiving terminal, and is mounted on a moving object 10. The receiving terminal 11 is realized by a computer or the like equipped with a processor (microprocessor), a memory, a communication interface, and the like.

[0039] In this embodiment, the receiving terminal 11 can be connected to the server 40 via a network such as the Internet, and can communicate with the server 40. The receiving terminal 11 can also obtain location information using a GPS (Global Positioning System).

[0040] FIG. 3 is a block diagram showing an example of the configuration of the receiving terminal 11 according to the present embodiment.

[0041] As shown in FIG. 3, the receiving terminal 11 includes a communication unit 111, a radio wave receiving unit 112, an arithmetic processing unit 113, and a memory 114, and is capable of receiving direct waves of radio waves transmitted by the transmitting station 20 and reflected waves of the radio waves, and is also capable of connecting to the server 40 via a network.

[0042] [1.1.2.1 Communication unit 111] The communication unit 111 communicates with the server 40 via the network.

[0043] In this embodiment, the communication unit 111 transmits at least a delay profile created by, for example, the calculation processing unit 113 described later to the server 40 via the network. The communication unit 111 may transmit the delay profile together with information related to the position and information related to the time to the server 40. The communication unit 111 also acquires, for example, instruction information described later from the server 40.

[0044] [1.1.2.2 Radio wave receiving unit 112] The radio wave receiving unit 112 receives radio waves transmitted by GPS satellites. The radio wave receiving unit 112 also receives direct waves of radio waves transmitted by the transmitting station 20 and reflected waves of the radio waves.

[0045] In this embodiment, the radio wave receiving unit 112 may be controlled by the arithmetic processing unit 113 with respect to the timing of receiving radio waves, i.e., direct waves of radio waves transmitted by the transmitting station 20 and reflected waves of the radio waves. For example, the radio wave receiving unit 112 may be controlled to receive radio waves at the timing indicated by the determination result of the determination unit 1135. Furthermore, the radio wave receiving unit 112 may be controlled to receive radio waves at predetermined time intervals.

[0046] In this embodiment, radio wave receiving unit 112 receives radio waves of, for example, terrestrial digital broadcasting, but the radio waves do not have to be terrestrial digital broadcasting as long as they can receive radio waves including a known pilot signal.

[0047] [1.1.2.3 Processing unit 113] FIG. 4 is a block diagram showing an example of a functional configuration of the arithmetic processing unit 113 shown in FIG.

[0048] The arithmetic processing unit 113 performs various processes using a CPU (not shown) and a memory 114. In this embodiment, the arithmetic processing unit 113 includes a delay profile creating unit 1131, an uploading unit 1132, a position identifying unit 1133, an instruction information acquiring unit 1134, and a determining unit 1135, as shown in FIG.

[0049] [1.1.2.3.1 Delay profile creation unit 1131] The delay profile creation unit 1131 creates a delay profile indicating the time difference between the direct wave and the reflected wave when the radio wave receiving unit 112 receives the direct wave and the reflected wave. The delay profiles created by the multiple receiving terminals 11 are used by the server 40 to identify a common reflector from information on the reflector that generates each reflected wave, and are used to identify the position of the reflector. Details will be described later. The delay profile creation unit 1131 creates a delay profile when the radio wave receiving unit 112 receives a radio wave. For example, when the radio wave receiving unit 112 receives a radio wave at a predetermined time interval, the delay profile creation unit 1131 may create a delay profile at a predetermined time interval. When the radio wave receiving unit 112 receives a radio wave at a timing indicated by the judgment result of the judgment unit 1135, the delay profile creation unit 1131 may create a delay profile at a timing according to the judgment result.

[0050] Here, the delay profile will be described.

[0051] FIG. 5 is a diagram for explaining the concept of a delay profile according to the present embodiment.

[0052] The delay profile represents the delay wave characteristics of the radio wave propagation path, and is shown as power information showing the relationship between delay time and received power. If there is a reflecting object in the propagation of the radio wave, the power shown in the delay profile will be maximized due to the reflection from the reflecting object. FIG. 5 shows an example in which there is one reflected wave received with a delay compared to the direct wave of the radio wave. Note that if there are multiple reflected waves received, multiple peaks indicating the reflected wave shown in FIG. 5 will appear. As shown in FIG. 5, the time difference between the direct wave and the reflected wave can be found from the delay profile, and the distance d between the receiving terminal 11 and the reflecting object can be found from the time difference.

[0053] Fig. 6 is a diagram for explaining an image of multipath. The same elements as in Fig. 1 are given the same reference numerals, and detailed explanations are omitted. Fig. 7 is a diagram conceptually showing an example of a delay profile caused by the multipath shown in Fig. 6.

[0054] In general radio wave propagation, a phenomenon occurs in which radio waves are reflected by terrain or structures and pass through multiple paths (multipath). In the example shown in Fig. 6, a radio wave transmitted from a transmitting station 20 is conceptually shown being reflected by six reflecting objects 30 and propagating to a mobile object 10 via multiple paths. This delay profile, as shown in Fig. 7, shows the reception of one direct wave and six reflected waves in terms of the power and time of the received radio waves.

[0055] [1.1.2.3.2 Upload section 1132] The upload unit 1132 transmits the delay profile created by the delay profile creation unit 1131 to the server 40 via the network. More specifically, the upload unit 1132 controls the communication unit 111 to transmit the delay profile created by the delay profile creation unit 1131 to the server 40 via the network.

[0056] The upload unit 1132 may transmit to the server 40 information relating to the position and time of the receiving terminal 11 when the radio wave receiving unit 112 received the radio wave, together with the delay profile.

[0057] The upload unit 1132 may execute the above-mentioned transmission operation at a predetermined time interval. The predetermined time interval may be every second, on the order of several hours, or on the order of once every few days. The upload unit 1132 may narrow the predetermined time interval when there is a phase fluctuation of the delayed wave with respect to the direct wave included in the delay profile created by the delay profile creation unit 1131, and may widen the predetermined time interval when the phase fluctuation of the delayed wave settles down, and execute the above-mentioned transmission operation.

[0058] Furthermore, upload unit 1132 may execute the above-mentioned transmission operation according to the determination result of determination unit 1135. For example, upload unit 1132 may execute the above-mentioned transmission operation according to the determination result that the current location of receiving terminal 11 is located within the receiving area. In this case, upload unit 1132 does not need to execute the above-mentioned transmission operation when the current location of receiving terminal 11 is not located within the receiving area.

[0059] [1.1.2.3.3 Location identification section 1133] The position specifying unit 1133 uses GPS to specify the position of the receiving terminal 11 when the radio wave receiving unit 112 receives the radio wave. In this embodiment, the position specifying unit 1133 uses GPS to specify the position of the receiving terminal 11 when the radio wave receiving unit 112 receives the direct wave of the radio wave transmitted by the transmitting station 20 and the reflected wave of the radio wave. The position specifying unit 1133 also uses GPS to acquire the time when the position of the receiving terminal 11 is specified, that is, the time when the radio wave receiving unit 112 receives the direct wave of the radio wave transmitted by the transmitting station 20 and the reflected wave of the radio wave.

[0060] [1.1.2.3.4 Instruction information acquisition unit 1134] The instruction information acquisition unit 1134 controls the communication unit 111 to acquire instruction information from the server 40. In this embodiment, the instruction information acquisition unit 1134 acquires instruction information from the server 40, the instruction information including a reception area of ​​a direct wave and a reflected wave that the receiving terminal 11 should receive.

[0061] [1.1.2.3.5 Judgment unit 1135] The determination unit 1135 determines whether or not the position of the receiving terminal 11 identified by the position identification unit 1133 is included in the receiving area included in the instruction information acquired by the instruction information acquisition unit 1134. As described above, when the determination unit 1135 determines that the identified position of the receiving terminal 11 is included in the receiving area included in the instruction information, the radio wave receiving unit 112 is controlled at the timing indicated by the determination result to receive the direct wave and the reflected wave of the radio wave.

[0062] Furthermore, the determination unit 1135 may estimate a future position, which is a position within a predetermined time from the specified current position of the receiving terminal 11. In this case, the determination unit 1135 may further determine whether or not the estimated future position is located in a receiving area included in the instruction information. In this way, when the determination unit 1135 determines that the future position is located in the receiving area and that the specified current position of the receiving terminal 11 is included in the receiving area, the radio wave receiving unit 112 is controlled to receive direct waves and reflected waves of radio waves at the timing indicated by the determination result.

[0063] [1.1.2.4 Memory 114] The memory 114 may store in advance at least one of a program for implementing the functions of the communication unit 111, the radio wave receiving unit 112, and the arithmetic processing unit 113, and an application that utilizes these functional configurations.

[0064] The memory 114 is also used to store data and the like when the above programs or applications are executed.

[0065] [1.2 Transmitting station 20] The transmitting station 20 has a fixed location and constantly or periodically transmits radio waves using the same modulation method. The transmitting station 20 may transmit the same radio waves using the OFDM (Orthogonal Frequency Division Multiplexing) method. For example, the transmitting station 20 may be a base station that transmits radio waves using a Japanese terrestrial digital broadcasting method.

[0066] Fig. 8A is a conceptual diagram of OFDM subcarriers adopted in terrestrial digital broadcasting. Fig. 8B is a conceptual diagram of SP signals inserted into radio waves of terrestrial digital broadcasting. Below, the Japanese terrestrial digital broadcasting (ISDB-T) will be explained.

[0067] Japan's terrestrial digital broadcasting employs a method called OFDM, which is less susceptible to delays caused by multipath propagation paths. OFDM is a method in which data is transmitted as a single block of data by carrying it on a large number of orthogonal subcarriers (carrier waves). For example, one OFDM frame is a combination of a large number of subcarriers as shown in Figure 8A. Furthermore, even if the subcarriers overlap with adjacent subcarriers as shown in Figure 8A, the data can be separated because they are orthogonal.

[0068] Incidentally, a known pilot signal is inserted not only in terrestrial digital broadcasting but also in basically all wireless communication. A pilot signal is a marker signal that is included in a signal and transmitted and received. In terrestrial digital broadcasting, an SP (Scattered Pilot) signal is used as the pilot signal. This SP signal is a known signal that is inserted at equal intervals in the frequency direction and the time direction, as shown in Fig. 8B, for example, and is a signal known on both the transmitting side and the receiving side.

[0069] The above-mentioned calculation processing unit 113 (specifically, the delay profile creation unit 1131) By examining the amplitude and phase of the SP signal, the distortion from a known state can be measured and a delay profile can be created.

[0070] [1.3 Reflective object 30] The reflecting object 30 reflects a direct wave of the radio wave transmitted by the transmitting station 20. The reflecting object 30 is, for example, a structure such as a building, and has a fixed location. Fig. 1 shows one of the multiple reflecting objects 30 that reflects the direct wave of the radio wave transmitted by the transmitting station 20 and causes the reflected wave to reach the receiving terminal 11.

[0071] [1.4 Server 40] The server 40 is, for example, an aggregation server or a cloud, and is realized by a computer or the like equipped with a processor (microprocessor), memory, a communication interface, and the like.

[0072] FIG. 9 is a block diagram showing an example of the configuration of the server 40 according to the present embodiment.

[0073] In this embodiment, as shown in FIG. 9, the server 40 includes a communication unit 401, a calculation processing unit 402, and a memory 403, and can connect to a receiving terminal 11 via a network such as the Internet, and can acquire information from at least one receiving terminal 11.

[0074] [1.4.1 Communication unit 401] The communication unit 401 can communicate with each of a plurality of receiving terminals 11 via a network.

[0075] In this embodiment, the communication unit 401 transmits, for example, a receiving area determined by the calculation processing unit 402 described later to the receiving terminal 11 via the network by including the receiving area in the instruction information. Also, the communication unit 111 acquires, for example, a delay profile from the receiving terminal 11. At this time, the communication unit 111 may acquire the delay profile from the receiving terminal 11 together with information related to the position and information related to the time.

[0076] [1.4.2 Processing unit 402] FIG. 10 is a block diagram showing an example of a functional configuration of the arithmetic processing unit 402 shown in FIG.

[0077] The arithmetic processing unit 402 performs various processes using a CPU (not shown) and a memory 403. In this embodiment, the arithmetic processing unit 402 includes an information acquisition unit 4021, a reflecting object position identification unit 4022, a map creation unit 4023, a target region determination unit 4024, a reflecting object selection unit 4025, an area determination unit 4026, and a water vapor amount estimation unit 4027, as shown in FIG.

[0078] [1.4.2.1 Information acquisition unit 4021] The information acquisition unit 4021 acquires a delay profile indicating a time difference between a direct wave and a reflected wave when the direct wave and the reflected wave are received by each of the three or more receiving terminals 11. More specifically, the information acquisition unit 4021 controls the communication unit 401 to acquire the delay profile from the receiving terminal 11 via the network.

[0079] The information acquisition unit 4021 may acquire information about the current location of the receiving terminal 11 when the receiving terminal 11 receives the direct wave and the reflected wave, and information about the time at the current location, together with the delay profile. The time interval for acquiring the delay profile may be every second, may be on the order of several hours, or may be on the order of once every several days.

[0080] Furthermore, the information acquisition unit 4021 may acquire a delay profile from one or more receiving terminals 11 at positions included in the area determined by the area determination unit 4026 described below, when the receiving terminal 11 receives a direct wave and a reflected wave.

[0081] [1.4.2.2 Reflector position identification unit 4022] The reflecting object position identifying section 4022 identifies the position of the reflecting object 30 that has reflected the reflected wave received by the receiving terminal 11 from the multiple delay profiles acquired by the information acquiring section 4021 .

[0082] 11A and 11B are diagrams for explaining a method for identifying the position of a reflecting object 30 from a plurality of delay profiles according to the embodiment.

[0083] First, the location of reflecting object 30 (on an elliptical curve with foci at transmitting station 20 position and receiving terminal 11 position) obtained from one delay profile will be described with reference to FIG. 11A.

[0084] 11A, from the delay profile, the difference in distance D between the path distance of the reflected wave (distance A + distance B) and the path distance of the direct wave (distance C) can be calculated from the difference in time between the radio waves transmitted at the same time arriving at the receiving terminal 11 as a direct wave and the time when the radio waves arrive at the receiving terminal 11 as a reflected wave (because the speed of the radio waves is known). Here, the distance difference D = (distance A + distance B - distance C).

[0085] On the other hand, since the position of receiving terminal 11 can be known from GPS information, distance C can be calculated separately from the known position of transmitting station 20. In other words, (distance A + distance B) = (distance difference D - distance C) = a constant value, and it is found that reflecting object 30 exists on an elliptical curve whose foci are the positions of transmitting station 20 and receiving terminal 11.

[0086] Next, using Figure 11B, we will explain the location of the reflecting object 30, obtained from the time difference between the direct wave and the reflected wave due to the delay profile, when the same transmitting station 20, the same reflecting object 30, and the receiving terminal 11 are in a different position as in Figure 11A.

[0087] As shown in FIG. 11B, in the same way as in FIG. 11A, an elliptic curve can be obtained whose foci are the position of the transmitting station 20 and the position of the receiving terminal 11.

[0088] Here, two elliptical curves sharing one focus either do not intersect or intersect at one to four points. FIG. 11B shows a case where they intersect at four points. In other words, one of these four points is the position of the reflecting object 30. This intersection point can be geometrically specified (the position of the reflecting object 30 can be specified). If there is no intersection point, it indicates that the two reflecting objects 30 associated with the two elliptical curves are different.

[0089] From the above, it can be seen that by fixing the transmitting station 20 and acquiring delay profiles from receiving terminals 11 at multiple positions, multiple elliptical curves on which the reflecting object 30 exists can be obtained, and the intersections of these elliptical curves become candidate positions for the reflecting object 30.

[0090] Note that, due to the positional relationship between the transmitting station 20 and the receiving terminal 11, and because there is not necessarily only one reflecting object 30, it cannot be said that a certain number of delay profiles must be collected to identify the position of one reflecting object 30. However, by collecting delay profiles from the receiving terminal 11 at many different positions in the server 40, it is possible to find the intersection points of the elliptic curves. For this reason, it can be said that an intersection point shared by many elliptic curves essentially indicates a certain reflecting object 30.

[0091] In other words, the reflecting object position identifying section 4022 can further identify the positions of a plurality of reflecting objects 30 that are different from each other by using a plurality of delay profiles acquired by the information acquiring section 4021.

[0092] [1.4.2.3 Map Creation Section 4023] The map creation unit 4023 creates a map in which the positions of the plurality of reflecting objects 30 are mapped for each predetermined area. In this embodiment, the map creation unit 4023 creates a map in which the positions of the plurality of reflecting objects 30 are mapped for each predetermined area, using the positions of the plurality of different reflecting objects 30 identified by the reflecting object position identification unit 4022. For example, the map creation unit 4023 may further acquire data on the land including the position where the receiving terminal 11 is located from land use 3D mesh data provided by the Ministry of Land, Infrastructure, Transport and Tourism. In this case, the map creation unit 4023 may create a map for each predetermined area of ​​the land, using the positions of the plurality of different reflecting objects 30 identified by the reflecting object position identification unit 4022 and the acquired data on the land.

[0093] FIG. 12 is a diagram showing an example of a map in which the positions of a plurality of reflecting objects 30 in a predetermined area are mapped according to the present embodiment.

[0094] 12, the map creation unit 4023 creates a map in which the positions of five reflectors 30a to 30e in a predetermined area are mapped, using the positions of the multiple different reflectors 30 identified by the reflector position identification unit 4022. Note that the map creation unit 4023 may create a map including the transmitting station 20 in the predetermined area in addition to the positions of the multiple reflectors 30 (the five reflectors 30a to 30e), as shown in FIG.

[0095] [1.4.2.4 Target area determination unit 4024] The target area determination unit 4024 determines a target area for performing water vapor amount estimation. The target area determination unit 4024 determines a target area for performing water vapor amount estimation, for example, by using a map for each predetermined area of ​​the land created by the map creation unit 4023.

[0096] Fig. 13 is a diagram for conceptually explaining the process for performing water vapor amount estimation according to this embodiment. That is, the target area determination unit 4024 may determine the target area 70 for performing water vapor amount estimation as shown in Fig. 13 by using the map shown in Fig. 9 created by the map creation unit 4023, for example.

[0097] [1.4.2.5 Reflection object selection section 4025] The reflecting object selection unit 4025 uses the map created by the map creation unit 4023 to select one reflecting object 30 in a predetermined area including the target area determined by the target area determination unit 4024 .

[0098] In this embodiment, the reflecting object selecting unit 4025 selects one reflecting object 30 from a plurality of reflecting objects 30 present in a predetermined area, for example, by using the map shown in Fig. 12 created by the map creating unit 4023. In the example shown in Fig. 13, the reflecting object selecting unit 4025 selects the reflecting object 30b, which is likely to be able to reflect the radio wave transmitted by the transmitting station 20, from the five reflecting objects 30a to 30e as viewed from the target area 70.

[0099] [1.4.2.6 Area Determination Unit 4026] The area determination unit 4026 determines, as the receiving area, an area obtained by extending a straight line connecting the position of one reflecting object selected by the reflecting object selection unit 4025 and the target area determined by the target area determination unit 4024. The area determination unit 4026 controls the communication unit 401 to transmit the determined receiving area (including it in instruction information) to the multiple receiving terminals 11 via the network.

[0100] 13, the area determination unit 4026 determines a receiving area 81 by extending a straight line connecting the reflecting object 30b selected by the reflecting object selection unit 4025 and the target area 70. In the example shown in Fig. 13, the area determination unit 4026 determines, as the receiving area 81, a range within a predetermined distance from a straight line 80 passing through the reflecting object 30b and the center of the target area 70. This receiving area 81 corresponds to the receiving area of ​​the direct wave and the reflected wave that the receiving terminal 11 should receive.

[0101] [1.4.2.7 Water vapor amount estimation unit 4027] The water vapor amount estimation unit 4027 estimates the amount of water vapor in the target region using the delay profile acquired by the information acquisition unit 4021.

[0102] Fig. 14 is a diagram for conceptually explaining the delay profile acquisition process for estimating the amount of water vapor according to this embodiment. The same elements as those in Fig. 13 are given the same reference numerals, and detailed explanations are omitted.

[0103] 14, for example, the water vapor amount estimation unit 4027 estimates the water vapor amount in the target area 70 using delay profiles acquired from one or more receiving terminals 11 (moving objects 10) included in the receiving area 81 determined by the area determination unit 4026. The example shown in FIG. 14 illustrates a case in which a plurality of moving objects 10a to 10d are moving, and a delay profile acquired only from the moving object 10c (receiving terminal 11) included in the receiving area 81 determined by the area determination unit 4026 is used to estimate the water vapor amount in the target area 70.

[0104] In addition, there are cases where a plurality of receiving terminals 11 (mobiles 10) constantly transmit delay profiles and the like to the server 40. In this case, the water vapor amount estimation unit 4027 may extract and use the delay profile acquired from one or more receiving terminals 11 included in the area determined by the area determination unit 4026 from among the plurality of acquired delay profiles.

[0105] The water vapor amount estimation unit 4027 then calculates the phase of the delayed wave relative to the direct wave (main wave) from the power information obtained from the delay profile. The water vapor amount estimation unit 4027 can calculate the variation in the amount of delay in the space (target area) through which the radio waves have passed, from the variation in the calculated phase of the delayed wave. The variation in the amount of delay can be regarded as a variation in the amount of water vapor in the space (target area). Therefore, the water vapor amount estimation unit 4027 can estimate the amount of water vapor in the space (target area) from multiple delay profiles acquired from one or more receiving terminals 11 that received the delayed wave.

[0106] Here, the principle by which the amount of water vapor can be estimated will be described.

[0107] Fig. 15A is a diagram showing the change in propagation delay of radio waves with respect to relative humidity at 1 atmosphere and 20°C. As shown in Fig. 15A, radio waves have the characteristic that their speed varies depending on the amount of water vapor in the air. In other words, radio waves propagate at the speed of light in a vacuum, but in air, the propagation speed changes depending on the amount of water vapor. For example, when radio waves propagate a distance of 5 km, a 1% increase in relative humidity causes a propagation delay of about 17 ps (about 5 mm in length). Therefore, it is clear that the amount of water vapor in the air can be measured by measuring the propagation speed of radio waves.

[0108] Fig. 15B is a diagram showing a configuration for measuring the propagation delay of radio waves according to a comparative example. Fig. 15B shows the configuration of a method (called a reflection method) for measuring the amount of water vapor by using two types of waves: a direct wave received directly between a transmitting station and a receiving point, and a reflected wave reflected from the transmitting station to a reflecting object to the receiving point.

[0109] The delay time of the delayed wave relative to the direct wave can be calculated from the phase difference of each radio wave in the delay profile. In addition, the phase θ of a general wave can be expressed in terms of frequency f and time t, as shown in (Equation 1). Since the delay time can be determined from the phase difference, the amount of water vapor can be calculated by converting it into the propagation speed.

[0110] θ=2πft (Equation 1)

[0111] In Fig. 15B, a transmitting station, shown as a radio tower, transmits radio waves by superimposing data on a signal with a standard frequency called a carrier wave. The oscillation of the oscillator that creates this standard frequency is not strictly constant, so phase noise (Φ1) occurs.

[0112] The receiving point, indicated as Receiver, receives radio waves with data carried on a signal of a reference frequency called a carrier wave. Therefore, at the receiving point, a signal of the reference frequency is also created and data is extracted from the transmitted radio waves, resulting in oscillator phase noise (Φ2).

[0113] In other words, in the reflection method, the phase change between the direct wave and the reflected wave (delayed wave) shown in Figure 15B includes the phase noise (Φ1+Φ2) of the transmitter other than the water vapor content change component, but these phase noises (Φ1+Φ2) are exactly the same. Therefore, by taking the difference, the effect of the phase noise (Φ1+Φ2) can be canceled and the phase difference between the reflected wave and the direct wave can be obtained.

[0114] In this way, by using the reflection method, the round-trip propagation delay between the receiving point and the reflector can be calculated with high accuracy, so that the amount of water vapor in the target area between the receiving point and the reflector can be estimated with high accuracy.

[0115] [1.4.3 Memory 403] The memory 403 may store in advance at least one of a program for implementing the functions of the communication unit 401 and the arithmetic processing unit 402 and an application that utilizes these functional configurations.

[0116] Furthermore, the memory 403 is used to store data and the like when the above programs or applications are executed.

[0117] [2. Overall system operation] The operation of the overall system configured as above will now be described.

[0118] [2.1 Operation of the receiving terminal 11 according to the embodiment] First, the operation of the receiving terminal 11 configured as above will be described below.

[0119] FIG. 16 is a flowchart showing an example of the operation of the receiving terminal 11 according to the present embodiment.

[0120] First, the receiving terminal 11 creates a delay profile when receiving the direct wave and the reflected wave of the transmitting station 20 (S10). More specifically, when the receiving terminal 11 mounted on the moving body 10 receives the direct wave of the radio wave transmitted by the transmitting station 20 and the reflected wave of the radio wave, it creates a delay profile indicating the time difference between the direct wave and the reflected wave when the direct wave and the reflected wave are received. By using the delay profile, the distance between the receiving terminal 11 and the reflecting object that reflected the reflected wave can be calculated from the time difference. Furthermore, as described above, the delay profile can also be used to estimate the amount of water vapor in the space (target area) through which the reflected wave passed.

[0121] Next, receiving terminal 11 transmits the delay profile created in step S10 to server 40 via the network (S11). More specifically, receiving terminal 11 transmits information regarding the position and time of receiving terminal 11 when receiving the radio wave together with the delay profile to server 40. The position and time of receiving terminal 11 are acquired using GPS.

[0122] [2.2 Server 40 Operation] Next, the operation of the server 40 configured as above will be described below.

[0123] Fig. 17 is a flowchart showing an example of the operation of the server 40 according to the present embodiment. Fig. 17 shows an example of the operation in which the server 40 specifies the position of the reflecting object 30 using the delay profile obtained from the receiving terminal 11, and creates a map using the specified position of the reflecting object 30.

[0124] First, the server 40 acquires data including a delay profile from each of two or more receiving terminals (S21). More specifically, the server 40 acquires, from each of two or more receiving terminals 11, information on the current position of the receiving terminal 11 when the receiving terminal 11 received the direct wave and the reflected wave, and information on the time at the current position, along with the delay profile. In the following, to simplify the explanation, it is assumed that only a maximum of one reflected wave is considered per delay profile from the delay profiles sent from each receiving terminal 11 to the server 40 (in general, the effects of multiple reflected waves are recorded).

[0125] Next, the server 40 obtains elliptic curves on which reflectors 30 that have reflected the reflected waves of the radio waves transmitted by the transmitting station 20 exist from the two or more delay profiles obtained in step S21, and further obtains a group of intersections of the elliptic curves geometrically from the two or more delay profiles. The group of intersections includes some that indicate the position of the reflector 30 and some that do not. If multiple elliptic curves share only one intersection, the intersection is identified as the position of the reflector 30 (S22). Here, if there is only one reflector 30 for the obtained delay profile, all the elliptic curves share only one intersection. If there are two reflectors 30, two groups of elliptic curves exist, and each group of elliptic curves share only one intersection. The detailed process will be described later with reference to FIG. 18.

[0126] Next, the server 40 creates a map in which the positions of the plurality of reflecting objects 30 are mapped for each predetermined area (S23). More specifically, the server 40 creates a map in which the positions of the plurality of reflecting objects 30 are mapped for each predetermined area, using the positions of the plurality of reflecting objects 30 that are different from each other and identified in step S22.

[0127] Fig. 18 is a flowchart showing detailed processing of step S22 in Fig. 17. Fig. 18 shows an example of a method for identifying the position of a reflecting object 30 according to this embodiment.

[0128] First, the server 40 extracts data acquired within a predetermined area one by one (S2201). More specifically, the server 40 acquires data including delay profiles acquired within the predetermined area one by one in order to identify the position of a reflecting object 30 included in the predetermined area.

[0129] Next, the server 40 determines whether the data extracted in step S2021 includes a delayed wave (S2202). The server 40 can determine whether the data includes a delayed wave by checking whether the delay profile included in each data includes a direct wave and its reflected wave (delayed wave).

[0130] In step S2202, if it is determined that the data does not include delayed waves (NO in S2202), the server 40 sets a flag for the data as data that will not be used to identify the position of a reflecting object in a predetermined area (S2203). After that, or if YES in step S2202, the server 40 determines whether it has determined whether delayed waves are included in the delay profile for all data (S2204), and if there is undetermined data (NO in S2204), the server 40 returns to step S2201 and starts the process again.

[0131] Step S2204 and subsequent steps are targeted at actual data whose delay profile includes delayed waves.

[0132] In step S2205, the following processes 1) to 4) are performed for each data (delay profile).

[0133] 1) The time difference between the direct wave and the delayed wave is calculated, and the product of that time difference and the transmission speed of the radio wave is used to calculate the difference (distance) between the path (distance) taken by the delayed wave and the path (distance) taken by the direct wave. 2) Calculate the position of the receiving terminal 11 from the data (which can be known from GPS data, for example) and the path (distance) that the direct wave will take from the known position of the transmitting station 20 3) Taking the above results into consideration, calculate the path (distance) of the delayed wave, i.e., (distance from the transmitting station 20 to the reflecting object 30) + (distance from the reflecting object 20 to the receiving terminal 11)

[0134] Here, the position of the reflecting object 20 cannot be specified, but it is clear that the sum of the distance from the reflecting object 20 to the transmitting station 20 and the distance to the receiving terminal 11 is a certain value (a constant value). This indicates that the reflecting object 20 exists on a certain elliptical curve whose foci are the positions of the transmitting station 20 and the receiving terminal 11.

[0135] 4) (Set up a coordinate system) and derive the equation of the elliptic curve geometrically

[0136] After the above process, the intersections of the elliptical curves are geometrically determined. Some of these intersections represent the position of the reflecting object 30, while others do not.

[0137] Next, in step S2206, the following process is carried out for each intersection.

[0138] That is, a process is performed to determine whether the group of elliptic curves having the intersection point intersects only at the intersection point.

[0139] Finally, in step S2207, the intersection points of the elliptic curves that intersect at only one point are identified as the positions of the reflecting objects 30.

[0140] In this way, the positions of a plurality of reflecting objects included in a predetermined area can be identified by performing the method for identifying the position of the reflecting object 30. This makes it possible to execute step S23 in FIG.

[0141] [2.3 Example of operation when estimating water vapor amount] Next, an example of an operation when the amount of water vapor is estimated in the entire system will be described.

[0142] Fig. 19 is a flowchart showing an example of the operation of estimating the amount of water vapor by the server 40 according to this embodiment. Fig. 19 shows an example of the operation of determining a receiving area using a map including the positions of a plurality of reflecting objects 30 created by the server 40, and estimating the amount of water vapor using a delay profile acquired from a receiving terminal 11 located in the receiving area. Hereinafter, the examples shown in Figs. 13 and 14 will be described as specific examples.

[0143] First, the server 40 determines a target area for estimating the amount of water vapor (S31) as shown in Fig. 19. In the example shown in Fig. 13, the server 40 determines a target area 70 for which the amount of steam estimation is to be performed.

[0144] Next, the server 40 selects one reflector 30 in a predetermined area including the target area using a map including the positions of the reflectors 30 for each predetermined area (S32). In the example shown in Fig. 13, the server 40 selects, using the map shown in Fig. 12, from the five reflectors 30a to 30e as viewed from the target area 70, the reflector 30b that is likely to be able to reflect the radio waves transmitted by the transmitting station 20.

[0145] Next, the server 40 determines, as the receiving area, an area obtained by extending a straight line connecting the position of the one reflecting object selected in step S32 and the target area determined in step S31 (S33). In the example shown in Fig. 13, the server 40 determines, as the receiving area 81, an area within a predetermined distance from a straight line 80 passing through the reflecting object 30b and the center of the target area 70.

[0146] Next, the server 40 acquires delay profiles from one or more receiving terminals 11 at positions included in the receiving area determined in step S33 when the receiving terminals 11 receive the direct waves and the reflected waves (S34). In the example shown in Fig. 14, the server 40 acquires delay profiles from one or more receiving terminals 11 (mobiles 10) included in the receiving area 81. More specifically, the server 40 acquires, from one or more receiving terminals 11 included in the receiving area 81, information on the current position of the receiving terminal 11 when the receiving terminal 11 receives the direct waves and the reflected waves and information on the time at the current position, together with the delay profiles.

[0147] In the example shown in Fig. 14, only the multiple receiving terminals 11 located within the receiving area 81 transmit delay profiles, etc. to the server 40. Here, the server 40 transmits instruction information including the determined receiving area 81 to the multiple receiving terminals 11, thereby making it possible for only the multiple receiving terminals 11 located within the receiving area 81 to transmit delay profiles, etc. to the server 40. This allows the server 40 to acquire delay profiles, etc. only from the multiple receiving terminals 11 located within the receiving area 81. Note that the multiple receiving terminals 11 may each constantly transmit their delay profiles, etc. to the server 40. In this case, the server 40 may extract delay profiles, etc. acquired from one or more receiving terminals 11 included in the receiving area 81 determined in step S33 from the multiple acquired delay profiles.

[0148] Next, the server 40 estimates the amount of water vapor in the target area determined in step S31 using the delay profile acquired in step S34 (S35). In the example shown in Fig. 14, the server 40 estimates the amount of water vapor in the target area 70 using the delay profile acquired from one or more receiving terminals 11 included in the receiving area 81.

[0149] Fig. 20 is a flowchart showing an example of the operation of the receiving terminal 11 when the water vapor amount estimation according to the present embodiment is performed. Fig. 20 shows an example of the operation when the receiving terminal 11 transmits a delay profile or the like to the server 40 when the receiving terminal 11 is located within the receiving area determined by the server 40.

[0150] First, the receiving terminal 11 acquires the receiving area from the server 40 (S331). More specifically, the receiving terminal 11 acquires from the server 40 the instruction information including the receiving area determined by the server 40.

[0151] Next, the receiving terminal 11 judges whether or not it is within the receiving area acquired in step S331 (S332). More specifically, the receiving terminal 11 can identify its own (the receiving terminal 11) position using GPS, and judges whether or not its own position is included in the receiving area.

[0152] If it is determined in step S332 that the receiving terminal 11 is within the receiving area (YES in S332), the receiving terminal 11 creates a delay profile when it receives the direct wave and the reflected wave from the transmitting station 20 (S333). More specifically, when the receiving terminal 11's own position is included in the receiving area, the receiving terminal 11 transmits information regarding the position and time of the receiving terminal 11 when it received the radio wave transmitted by the transmitting station 20, together with the delay profile, to the server 40. Note that if it is determined in step S332 that the receiving terminal 11 is not within the receiving area (NO in S332), the process returns to step S331 and is repeated.

[0153] Next, the receiving terminal 11 transmits the delay profile etc. created in step S333 to the server 40 via the network (S334). The process of step S334 is similar to the process of step S11, and therefore a description thereof will be omitted.

[0154] [3. Effects, etc.] As described above, the mobile receiving terminal 11 according to the present embodiment transmits to the server 40 a delay profile obtained when receiving a direct wave of radio waves and a reflected wave of radio waves transmitted by a transmitting station 20 such as a broadcasting station, which has a fixed location and periodically transmits the same radio waves. As a result, even if the receiving terminal 11 is mobile, the position of a reflecting object can be identified by using the delay profile transmitted by the receiving terminal 11. In other words, it is possible to realize an information transmission method and a mobile receiving terminal that can transmit information that can identify the position of a reflecting object that reflects radio waves from a transmitting station 20 such as a broadcasting station.

[0155] Furthermore, according to the server 40 of this embodiment, even when a movable receiving terminal 11 mounted on a moving object 10 is used, it is possible to identify the position of a reflecting object 30 that reflects radio waves from a transmitting station 20 such as a broadcasting station. Then, according to the server 40 of this embodiment, it is possible to estimate the amount of water vapor by utilizing the identified position of the reflecting object 30 and using a delay profile acquired from the receiving terminal 11. In other words, even when a mobile receiving terminal is used, it is possible to identify the position of a reflecting object that reflects radio waves from a transmitting station such as a broadcasting station, and it is possible to realize an information processing method that can estimate the amount of water vapor.

[0156] (Possibility of other embodiments) Although the information transmission method, information processing method, and mobile receiving terminal of the present disclosure have been described above in the embodiments, there are no particular limitations on the subject or device that performs each process. In the information processing method, the process may be performed by a processor (described below) incorporated in a specific device that is locally arranged. In addition, in the information processing method, the process may be performed by a cloud server that is located in a place different from the local device.

[0157] The present disclosure is not limited to the above-mentioned embodiment. For example, the present disclosure may be realized by combining the components described in this specification in any way, or by excluding some of the components. In addition, the present disclosure also includes modifications obtained by applying various modifications that a person skilled in the art can think of to the above-mentioned embodiment without departing from the gist of the present disclosure, that is, the meaning of the words described in the claims.

[0158] The present disclosure also includes the following cases:

[0159] (1) The above-mentioned device is specifically a computer system consisting of a microprocessor, ROM, RAM, a hard disk unit, a display unit, a keyboard, a mouse, etc. A computer program is stored in the RAM or hard disk unit. The microprocessor operates according to the computer program, causing each device to achieve its function. Here, the computer program is composed of a combination of multiple instruction codes that indicate commands for a computer to achieve a specified function.

[0160] (2) Some or all of the components constituting the above-mentioned device may be composed of one system LSI (Large Scale Integration). The system LSI is an ultra-multifunctional LSI manufactured by integrating multiple components on one chip, and specifically, is a computer system including a microprocessor, ROM, RAM, etc. A computer program is stored in the RAM. The system LSI achieves its functions by the microprocessor operating in accordance with the computer program.

[0161] (3) Some or all of the components constituting the above-mentioned device may be composed of an IC card or a standalone module that is detachable from each device. The IC card or the module is a computer system composed of a microprocessor, ROM, RAM, etc. The IC card or the module may include the above-mentioned ultra-multifunction LSI. The microprocessor operates according to a computer program, causing the IC card or the module to achieve its functions. The IC card or the module may be tamper-resistant.

[0162] (4) The present disclosure may also be a computer system having a microprocessor and a memory, the memory storing the above-mentioned computer program, and the microprocessor operating in accordance with the computer program. [Industrial Applicability]

[0163] The present disclosure can be used in an information transmission method and a mobile receiving terminal that transmit a delay profile used to estimate the amount of water vapor in a desired target area and that can identify the position of a reflecting object, as well as an information processing method that can identify the position of a reflecting object using an acquired delay profile and estimate the amount of water vapor in a desired target area. [Explanation of symbols]

[0164] 10, 10a, 10b, 10c, 10d Mobile 11 Receiving terminal 12 Drive unit 20 Transmitting Station 30, 30a, 30b, 30c, 30e, 30d reflective object 40 Servers 70 Target Areas 80 straight line 81 Reception area 111, 401 Communications Department 112 Radio wave receiving unit 113, 402 Processing unit 114,403 Memory 1131 Delay profile creation unit 1132 Upload Section 1133 Location identification part 1134 Instruction information acquisition unit 1135 Judgment section 4021 Information Acquisition Department 4022 Reflective object position identification part 4023 Map Creation Department 4024 Target area determination unit 4025 Reflector Selection Section 4026 Area Determination Unit 4027 Water Vapor Estimation Unit

Claims

1. An information transmission method for a mobile receiving terminal that has a fixed location, can receive direct waves and reflected waves of radio waves transmitted from a transmitting station that constantly or periodically transmits radio waves using the same modulation method, and can connect to a server via a network, comprising: creating a delay profile indicating a time difference between the direct wave and the reflected wave when the direct wave and the reflected wave are received; an upload step of transmitting the delay profile to the server via the network; The information transmission method further includes a position determination step of determining a position of the mobile receiving terminal when the direct wave and the reflected wave are received, In the upload step, Transmitting information about the specified position and information about the time when the direct wave and the reflected wave were received together with the delay profile to the server; The information transmission method further includes: An acquisition step of acquiring instruction information including a receiving area of ​​the direct wave and the reflected wave from the server; a determination step of determining whether or not the position identified in the position identification step is included in the receiving area included in the instruction information; a radio wave receiving step of receiving the direct wave and the reflected wave when it is determined in the determining step that the position is included in the receiving area; In the creating step, the delay profile is created when the direct wave and the reflected wave received in the radio wave receiving step are received. How information is transmitted.

2. An information transmission method for a mobile receiving terminal that has a fixed location, can receive direct waves and reflected waves of radio waves transmitted from a transmitting station that constantly or periodically transmits radio waves using the same modulation method, and can connect to a server via a network, comprising: creating a delay profile indicating a time difference between the direct wave and the reflected wave when the direct wave and the reflected wave are received; an upload step of transmitting the delay profile to the server via the network; The information transmission method further includes a position determination step of determining a position of the mobile receiving terminal when the direct wave and the reflected wave are received, In the upload step, Transmitting information about the specified position and information about the time when the direct wave and the reflected wave were received together with the delay profile to the server; The information transmission method further includes: An acquisition step of acquiring instruction information including a receiving area of ​​the direct wave and the reflected wave from the server; a position estimation step of estimating a future position, which is a position within a predetermined time from a current position of the mobile receiving terminal, a future position determination step of determining whether or not the future position estimated in the position estimation step is located in the receiving area included in the instruction information; a radio wave receiving step of receiving the direct wave and the reflected wave when the current position of the mobile receiving terminal is included in the receiving area when the future position determining step determines that the future position is located in the receiving area, In the creating step, the delay profile is created when the direct wave and the reflected wave received in the radio wave receiving step are received. How information is transmitted.

3. The information transmission method includes: The uploading step is performed at predetermined time intervals.

3. The information transmission method according to claim 1 or 2.

4. The transmitting station transmits the same radio wave using an OFDM (Orthogonal Frequency Division Multiplexing) method. The information transmission method according to any one of claims 1 to 3.

5. An information processing method of a server that can be connected via a network to a plurality of mobile receiving terminals that are fixed in location and can receive direct waves and reflected waves of radio waves transmitted from a transmitting station that constantly or periodically transmits radio waves of the same modulation method, comprising: an information acquisition step of acquiring, from each of the plurality of mobile receiving terminals, information regarding the current location of the mobile receiving terminal when the mobile receiving terminal receives the direct wave and the reflected wave, and a delay profile indicating the arrival time difference between the direct wave and the reflected wave; a position specifying step of deriving an elliptic curve on which a reflecting object that has reflected the reflected wave may exist, based on each of the acquired delay profiles and information related to the current position of the mobile receiving terminal, calculating an intersection point between the multiple elliptic curves obtained in relation to the multiple delay profiles, and specifying the intersection point as the position of the reflecting object when two or more of the elliptic curves intersect only at the intersection point, The position specifying step further includes specifying positions of the plurality of reflecting objects that are different from each other, The information processing method further comprises: A map creating step of creating a map in which the positions of the plurality of reflecting objects are mapped for each predetermined area, The information processing method further comprises: A target area determination step of determining a target area; a reflecting object selection step of selecting one reflecting object in a predetermined area including the target area by using the map created in the map creation step; A determination step of determining an area obtained by extending a straight line connecting the position of the one reflecting object and the target area as a receiving area; an area information acquisition step of acquiring a delay profile when the mobile receiving terminal receives the direct wave and the reflected wave from one or more mobile receiving terminals at positions included in the receiving area; an estimation step of estimating a water vapor amount in the target area using the delay profile acquired in the area information acquisition step; Information processing methods.

6. In the information acquisition step, acquiring information about the time at the current location when the mobile receiving terminal receives the direct wave and the reflected wave together with the delay profile; The information processing method according to claim 5.

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