Communication device, communication system, and communication method

Abstract

[Problem] To make it possible to acquire accurate distance information using a simple configuration, and to perform highly reliable position measurement. [Solution] A communication device comprising a distance acquiring unit for acquiring distance information calculated on the basis of propagation channel characteristics, and an altitude acquiring unit for acquiring altitude information.

Description

Technical Field

[0001] The present disclosure relates to a communication device, a communication system, and a communication method.

Background Art

[0002] In recent years, indoor positioning technology has attracted attention. Indoors, since satellite radio waves do not reach, there is a problem that signals of GPS (Global Positioning System) or GNSS (Global Navigation Satellite System) cannot be received, and various methods have been proposed. For example, PDR (Pedestrian Dead Reckoning) that measures the user's movement and the amount of movement by a plurality of sensors such as an acceleration sensor and a gyro sensor, a method of estimating the position by collating geomagnetic data, a method of estimating the distance by the flight time from when light is projected until it is received (ToF: Time of Flight), and the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, for example, in the PDR method, ranging errors accumulate, but there is no means to correct them, which is an issue. Also, in methods that require data collation such as geomagnetic data, creation of a pre-map is essential, and there are major problems in terms of operation such as the need to recreate collation data again when the layout changes or the map changes. The ToF method is greatly affected by shadowing (decrease in ranging performance due to the human body), and there is a problem that correct distances cannot be measured unless the environment is a line-of-sight environment.

[0005] In order to solve this problem, ranging methods using wireless signals have been attracting attention more than before. This is because many wireless communication ICs such as BLE (Bluetooth Low Energy), Wifi, and LTE (Long Term Evolution) are already built into smartphones, eliminating the need for pre-learning and facilitating deployment to applications. However, the ranging accuracy of ranging methods using wireless signals has been an issue.

[0006] As a current solution, a method using RSSI (Received Signal Strength Indicator) is being commercialized. This is a method of determining that if the signal is large, it is close, and if it is small, it is far, but it is known to be easily affected by multipath (reflected waves). Also, there is a problem that a large error occurs in the received signal strength depending on the angle of the antenna. Therefore, the present disclosure provides a communication device, a communication system, and a communication method that can acquire distance information with high accuracy with a simple configuration and perform highly reliable positioning.

Means for Solving the Problem

[0007] In order to solve the above problems, according to the present disclosure, there is provided a communication device including a distance acquisition unit that acquires distance information calculated based on propagation channel characteristics, and an altitude acquisition unit that acquires altitude information.

[0008] It may further include a communication unit that transmits the distance information and the altitude information to a processing device.

[0009] The distance acquisition unit may acquire the distance information calculated from the relationship between the frequencies and phases of a plurality of propagation channels.

[0010] The distance acquisition unit may directly acquire the distance information from the positioning phase calculated based on the group delay calculated from the relationship between the frequencies and phases of a plurality of propagation channels.

[0011] The distance acquisition unit may acquire the distance information based on a radio signal in the UWB (Ultra WideBand) band.

[0012] The altitude acquisition unit may acquire the altitude information based on the atmospheric pressure detected by an atmospheric pressure sensor. The altitude acquisition unit may acquire the altitude information based on the atmospheric pressure detected by the atmospheric pressure sensor and the temperature detected by a temperature sensor.

[0013] According to the present disclosure, there is provided a processing device including: a distance acquisition unit that acquires a plurality of distance information calculated from the relationships between the frequencies and phases of a plurality of propagation channels; an altitude acquisition unit that acquires altitude information through communication; and a position detection unit that detects position information based on the distance information and the altitude information.

[0014] The distance acquisition unit acquires three or more pieces of the distance information regarding the distances between the object and three or more communication partner devices, and the position detection unit may detect the position of the object based on the three or more pieces of distance information and the altitude information.

[0015] The altitude acquisition unit acquires three or more pieces of the altitude information from the three or more communication partner devices, and the position detection unit may detect the position of the object based on the three or more pieces of distance information and the three or more pieces of altitude information.

[0016] The distance acquisition unit calculates the distance information between the object and the three or more communication partner devices at the object by transmitting and receiving radio signals of a plurality of frequencies with the three or more communication partner devices to calculate the phases, and the position detection unit may detect the position of the object based on the three or more pieces of distance information calculated by the distance acquisition unit and the three or more pieces of altitude information.

[0017] The distance acquisition unit acquires the three or more pieces of distance information calculated by the three or more communication partner devices when the object communicates with the three or more communication partner devices, and the position detection unit may detect the position of the object based on the three or more pieces of distance information and the three or more pieces of altitude information acquired by the distance acquisition unit.

[0018] The position detection unit may create a three-dimensional map indicating position information within a predetermined three-dimensional space based on the distance information.

[0019] The distance acquisition unit acquires three or more pieces of the distance information between the object and three or more communication partner devices. The position detection unit may create the three-dimensional map based on the three or more pieces of distance information.

[0020] The three-dimensional map may include the position information of the object and the three or more communication partner devices.

[0021] The distance acquisition unit acquires three or more pieces of the distance information regarding the distance between the object and three or more communication partner devices. The altitude acquisition unit acquires three or more pieces of the altitude information from the three or more communication partner devices. The position detection unit may create the three-dimensional map based on the three or more pieces of distance information and the three or more pieces of altitude information.

[0022] According to the present disclosure, there is provided a processing device including: a distance acquisition unit that acquires a plurality of pieces of distance information calculated from the relationships of the frequencies and phases of a plurality of propagation channels; a position acquisition unit that acquires absolute position information of at least one point; and a position detection unit that detects position information based on the plurality of pieces of distance information and the absolute position information acquired by the position acquisition unit. a position acquisition unit that acquires absolute position information periodically or aperiodically; and a position detection unit that detects position information based on the plurality of pieces of distance information and the absolute position information acquired by the position acquisition unit.

[0023] The position acquisition unit acquires the absolute position information periodically or aperiodically. The position detection unit may update the position information based on the absolute position information acquired by the position acquisition unit periodically or irregularly.

[0024] It may further include an altitude acquisition unit that acquires altitude information through communication, The position detection unit may detect the position information based on the plurality of distance information, the absolute position information, and the altitude information.

[0025] The altitude information includes altitude difference information regarding the altitude difference between two points, It may further include a reliability estimation unit that estimates the reliability of the distance information based on the distance information and the altitude difference information.

[0026] It may further include a position acquisition unit that acquires absolute position information of at least one point.

[0027] The position acquisition unit may acquire GPS (Global Positioning System) information.

[0028] According to the present disclosure, there is provided a communication system including a first communication device, a second communication device that transmits and receives wireless signals to and from the first communication device, a distance acquisition unit that acquires distance information calculated based on propagation channel characteristics, an altitude acquisition unit that acquires altitude information, and a position detection unit that detects position information based on the distance information and the altitude information.

[0029] It includes a third communication device that transmits and receives wireless signals to and from the second communication device, the second communication device has the distance acquisition unit and the altitude acquisition unit, the third communication device has the position detection unit, the distance acquisition unit acquires the distance information from the first communication device, and the position detection unit may detect the position information based on the distance information and the altitude information.

[0030] According to the present disclosure, distance information calculated based on propagation channel characteristics is obtained, altitude information is obtained, and a communication method for detecting location information based on the distance information and the altitude information is provided.

Brief Description of the Drawings

[0031]

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Embodiments for Carrying Out the Invention

[0032] Hereinafter, embodiments of a communication device, a communication system, and a communication method will be described with reference to the drawings. Hereinafter, the description will focus on the main components of the communication device and the communication system, but the communication device and the communication system may have components and functions that are not illustrated or described. The following description does not exclude components and functions that are not illustrated or described.

[0033] (First Embodiment) FIG. 1 is a block diagram showing the configuration of the main part of a communication device 1 according to the first embodiment. The communication device 1 in FIG. 1 includes an antenna 2, a transmission unit 3, a reception unit 4, a distance acquisition unit 5, and an altitude acquisition unit 6. In this specification, the transmission unit 3 and the reception unit 4 may be collectively referred to as a communication unit.

[0034] The distance acquisition unit 5 acquires distance information calculated based on propagation channel characteristics. The propagation channel characteristics refer to the characteristics of a radio signal while propagating through a propagation path, for example, the phase difference that occurs while propagating through the propagation path. The distance acquisition unit 5 may calculate the distance information inside the communication device 1 in FIG. 1, or may acquire the distance information via the reception unit 4. The distance acquisition unit 5 acquires, for example, distance information calculated from the relationship between the frequencies and phases of a plurality of propagation channels. Alternatively, the distance acquisition unit 5 may directly acquire the distance information from the measured phase calculated based on the group delay calculated from the relationship between the frequencies and phases of a plurality of propagation channels.

[0035] The altitude acquisition unit 6 acquires altitude information. The altitude acquisition unit 6 may acquire, for example, altitude information detected by an altitude sensor provided in the communication device 1 in FIG. 1. The altitude sensor may be a pressure sensor, and the altitude acquisition unit 6 may acquire altitude information based on the pressure detected by the pressure sensor. Alternatively, the altitude acquisition unit 6 may acquire altitude information based on the pressure detected by the pressure sensor and the temperature detected by a temperature sensor. Alternatively, the altitude acquisition unit 6 may acquire the altitude information of the communication partner device via the reception unit 4.

[0036] The communication device 1 in FIG. 1 may perform various information processes based on the distance information acquired by the distance acquisition unit 5 and the altitude information acquired by the altitude acquisition unit 6, or alternatively, may transmit the distance information and the altitude information to a processing device such as a server via the transmission unit 3.

[0037] FIG. 2 is a block diagram that more specifically shows the communication device 1 according to the first embodiment than FIG. 1. The communication device 1 in FIG. 2 includes an antenna 2, a transmission unit 3, a reception unit 4, a clock generator 7, a distance calculation unit 8, an altitude calculation unit 9, an altitude sensor 10, and an interface (IF) unit 30.

[0038] The clock generator 7 has a local oscillator that generates a local oscillation signal used for modulation processing in the transmission unit 3 and demodulation processing in the reception unit 4.

[0039] The distance calculation unit 8 calculates distance information based on the propagation channel characteristics. For example, the distance calculation unit 8 may calculate the distance information by, for example, a phase-based method or a UWB (Ultra WideBand) method. Details of the phase-based method and the UWB method will be described later. The distance calculation unit 8 has the function of the distance acquisition unit 5 in FIG. 1.

[0040] The altitude calculation unit 9 calculates altitude information based on the signal detected by the altitude sensor 10. The altitude calculation unit 9 has the function of the altitude acquisition unit 6 in FIG. 1. The altitude sensor 10 may be, for example, a pressure sensor. Since the atmospheric pressure changes with height, altitude information can be calculated from the detection signal of the pressure sensor. Since the atmospheric pressure is affected by temperature, by including not only a pressure sensor but also a temperature sensor as the altitude sensor 10, the altitude calculation unit 9 can correct the atmospheric pressure detected by the pressure sensor according to the temperature detected by the temperature sensor. The interface unit 30 inputs and outputs various signals. The communication device 1 in FIG. 2 may include a GPS (Global Positioning System) reception unit 51 and a position acquisition unit 52. The GPS reception unit 51 receives GPS signals from GPS satellites. The position acquisition unit 52 acquires at least one point of absolute position information based on the received GPS signals.

[0041] The communication device 1 in FIG. 1 may be a mobile communication device such as a smartphone or a mobile phone, or may be a beacon device installed at a predetermined location, or may be a radio station such as a base station or a server that performs wireless communication with a mobile communication device or a beacon device.

[0042] The communication device 1 in FIG. 1 calculates distance information from a communication partner device based on propagation channel characteristics by performing wireless communication with the communication partner device. Hereinafter, as a specific example of the propagation channel characteristics, a method for calculating distance information from a communication partner device using a phase-based method will be described.

[0043] FIG. 3 is a diagram for explaining the outline of the phase-based method. In the phase-based method, a radio signal is transmitted and received between an initiator 11 and a reflector 12 to estimate the phase difference of the propagation path between the initiator 11 and the reflector 12. The initiator 11 and the reflector 12 have the same configuration as the communication device 1 in FIG. 1 or FIG. 2, for example.

[0044] FIG. 3 is a diagram showing the phase-based method. An example is shown in which a radio signal in a frequency band of 2.4 GHz is transmitted and received between an initiator 11 and a reflector 12, and the phase difference θ of the transmission path is measured by a control unit 13. As shown in FIG. 3, when the horizontal axis is the frequency ω and the vertical axis is the phase difference θ, the phase difference θ changes almost linearly according to the frequency. The group delay τ can be calculated from the slope of the phase difference. The group delay τ is obtained by differentiating the phase difference θ between the input waveform and the output waveform with respect to the angular frequency ω. Since the phase cannot distinguish the difference from a phase shifted by an integer multiple of 2π, the group delay is used as an index representing the characteristics of the filter circuit.

[0045] When the phase difference between the transmission signal and the reception signal is θd, the measured phase is θm, the distance of the propagation path is D, and the speed of light is c, the following equation (1) holds. θd (= θm + 2πn) = ωtd = ω × 2D / c …(1)

[0046] When both sides of equation (1) are differentiated with respect to the angular frequency ω, equation (2) is obtained.

Number

[0047] When Equation (2) is transformed, the distance D is obtained by the following Equation (3).

Number

[0048] Figure 4 is a block diagram showing an example of the internal configuration of the phase-based initiator 11 and reflector 12. The internal configurations of both the initiator 11 and the reflector 12 are the same. The initiator 11 and reflector 12 in Figure 4 include an antenna 2, a transmitter 3, a receiver 4, and a control unit 13. The transmission signal output from the transmitter 3 and the reception signal received by the antenna 2 are switched by a high-frequency switch (RF-SW) 14. The transmitter 3 and the receiver 4 perform modulation processing and demodulation processing in synchronization with the clock output from the frequency synthesizer 15.

[0049] The transmitter 3 includes a modulator 21, a DA converter (DAC) 22, a band-pass filter (BPF) 23, and a mixer 24 within the control unit 13. The receiver 4 includes a low-noise amplifier (LNA) 31, a mixer 32, a band-pass filter (BPF) 33 and a variable gain amplifier (VGA) 34 for the I channel, a BPF 35 and a VGA 36 for the Q channel, and an analog-to-digital converter (ADC) 37.

[0050] The control unit 13 includes a modulator 21, a phase measurement unit 41, a RAM 43, and an automatic gain control unit (AGC) 44.

[0051] The digital demodulation signal output from the receiver 4 is stored in the RAM 43 after the phase difference between the transmission signal and the reception signal is measured for each frequency channel by the phase measurement unit 41. The phase measurement unit 41 may perform digital signal processing such as averaging, filtering, and FFT.

[0052] FIG. 5 is a diagram showing an example of a signal sequence transmitted and received between the phase-based initiator 11 and the reflector 12. First, settings for starting distance measurement are performed (step S1). In step S1, for example, device authentication as to whether it is a device compliant with BLE (Bluetooth Low Energy), negotiation, frequency offset correction, AGC gain setting, etc. are performed. In the negotiation, confirmation as to whether it is a device capable of distance measurement, confirmation of distance measurement setting parameters, etc. are performed.

[0053] Next, for example, the frequency is swept within the range of 2400 MHz to 2480 MHz used by BLE, phase measurement is performed for each frequency channel, and distance information is calculated (step S2). When the distance information is calculated in step S2, next, data communication is performed between the initiator 11 and the reflector 12 (step S3), and data including the distance information and altitude information is transmitted and received.

[0054] FIGS. 6A, 6B, and 6C are specific examples of packets transmitted and received by the phase-based initiator 11 and the reflector 12. FIG. 6A is a packet configuration diagram transmitted from the initiator 11 during phase measurement. FIG. 6B is a packet configuration diagram of a modified example of FIG. 6A. FIG. 6C is a packet configuration diagram at the start of data communication.

[0055] The packet of FIG. 6A has a preamble d1, an access address d2, and a phase measurement signal d3. The phase measurement signal d3 is a single carrier signal. The packet of FIG. 6B has a PDU (Protocol Data Unit) d4 and a CRC (Cyclic Redundancy Check) d5 in addition to the packet configuration of FIG. 6A. The packet of FIG. 6C has a preamble d1, an access address d2, a PDU d4, and a CRC d5. Note that FIGS. 6A to 6C are an example of the packet configuration, and various modified examples are conceivable.

[0056] As shown in FIGS. 6A and 6B, the initiator 11 transmits a single carrier signal to the reflector 12. However, if the signal only travels from the initiator 11 to the reflector 12 in one direction, the phase difference of the propagation path cannot be correctly detected due to the influence of the local phase. Therefore, in the phase-based method, a process of canceling the local phase is performed by reciprocating the signal between the initiator 11 and the reflector 12.

[0057] FIGS. 7 to 9 are diagrams for explaining a method of canceling the local phase. As shown in FIGS. 7 to 9, the frequency synthesizer 15 in FIG. 4 has a local oscillator 7a and a 90-degree phase shifter 7b. FIG. 7 shows an example in which a transmission signal cosωt converted into an intermediate frequency signal by a local oscillation signal is transmitted from the initiator 11 to the reflector 12. In FIG. 7, the phase difference while the transmission signal propagates through the propagation path is denoted as φ. In this case, the reflector 12 receives the signal cos(ωt + φ). Assuming that the local oscillator 7a inside the reflector 12 has a local phase θ, the local oscillation signal is represented by cos(ωt + φ). Therefore, the I signal generated by the reflector 12 is represented by I(t) = cos(φ - θ) / 2, and the Q signal is represented by Q(t) = sin(φ - θ) / 2.

[0058] Thus, the measured phase of the reflector 12 is φ - θ. This measured phase can be detected by an arithmetic unit or the like provided in the reflector 12. This arithmetic unit is built into, for example, an IC (Integrated Circuit) chip that executes the functions of the reflector 12.

[0059] FIG. 8 shows an example in which a transmission signal cos(ωt + θ) converted into an intermediate frequency signal by a local oscillation signal is transmitted from the reflector 12 to the initiator 11. θ is the local phase of the local oscillator 7a of the reflector 12 as described above. In this case, the initiator 11 receives the signal cos(ωt + φ + θ). Therefore, the I signal generated by the initiator 11 is represented by I(t) = cos(φ + θ) / 2, and the Q signal is represented by Q(t) = sin(φ + θ) / 2.

[0060] Thus, the measured phase of the initiator 11 becomes φ + θ. This measured phase can be detected by an arithmetic unit or the like provided in the initiator 11. This arithmetic unit is built into, for example, an IC chip that executes the functions of the initiator 11.

[0061] FIG. 9 shows an example of adding the measured phase (φ - θ) at the reflector 12 in FIG. 7 and the measured phase (φ + θ) at the initiator 11 in FIG. 8. It can be seen that (φ - θ) + (φ + θ) = 2φ, and the influence of the local phase can be canceled out. This addition operation can be executed by an arithmetic unit or the like in the IC chip for the reflector 12 or the initiator 11 described above.

[0062] Thus, by reciprocating a signal between the initiator 11 and the reflector 12, the phase difference of the transmission line can be detected without being affected by the local phase θ. If the phase difference of the propagation path can be detected, the distance of the propagation path can be calculated by the above-described formulas (1) to (3).

[0063] FIG. 10 is a diagram showing signal transmission and reception in the communication system according to the first embodiment. The device dv1 in FIG. 10 is a mobile communication device such as a smartphone, and the devices dv2 to dv4 are beacon devices installed at a predetermined location, for example. The devices dv1 to dv4 all have a configuration similar to that of the communication device 1 in FIG. 2, for example. In the example of FIG. 10, in accordance with the request of the device dv1, the devices dv2 to dv4 send information for calculating the distance, their own coordinates, and altitude information to the device dv1.

[0064] The information for calculating the distance is, for example, a single-carrier signal. The device dv1 transmits a single-carrier signal to each of the devices dv2 to dv4, and the devices dv2 to dv4 return the same signal to the device dv1. Thus, as described above, the device dv1 can calculate the distance information with each of the devices dv2 to dv4. Also, the devices dv2 to dv4 send their own coordinate information and altitude information to the device dv1. Thereby, the device dv1 can perform high-precision positioning regardless of its height based on the distance information with each of the devices dv2 to dv4 and the altitude information of each of the devices dv2 to dv4.

[0065] Figure 11 is a flowchart showing the processing operation of the device dv1. First, the planar coordinate information of the devices dv2 to dv4 is acquired (step S11). In this step S11, the own coordinate information of each device sent from the devices dv2 to dv4 is acquired.

[0066] Next, the altitude information of each of the devices dv1 to dv4 is acquired (step S12). If the device dv1 is equipped with the altitude sensor 10, the device dv1 acquires the altitude information by the altitude sensor 10. Also, the altitude information sent from the devices dv2 to dv4 is acquired.

[0067] Next, the distance information between the device dv1 and the devices dv2 to dv4 is acquired (step S13). As described above, for example, by reciprocating signals for each frequency channel between the device dv1 and the devices dv2 to dv4 in a phase-based method, the distance information can be calculated. Note that the calculation of the distance information does not necessarily have to be performed by the device dv1, and the device dv1 may acquire the results of each of the devices dv2 to dv4 calculating the distance information with the device dv1.

[0068] Next, it is determined whether there is distance information for three or more points (step S14). To identify the position of device dv1, it is necessary to measure the distances to three or more other devices around device dv1. Therefore, in step S14, it is determined whether there is distance information for three or more points. If not, the process returns to step S13 to obtain new distance information.

[0069] If it is determined in step S14 that there is distance information for three or more points, it is determined whether there is altitude information for three or more points (step S15). When detecting the position of device dv1, including altitude information can provide benefits in improving the position detection accuracy beyond simply increasing the number of distance information by one. Indoor positioning is not always able to provide highly reliable distance measurements due to the influence of multipath where wireless signals are reflected by surrounding metal members and the like. In contrast, altitude sensor 10 such as a barometric pressure sensor has high detection accuracy and can reliably detect altitude information even in a multipath environment. Therefore, by using altitude information for position detection, the accuracy of position detection can be improved. Also, the more altitude information there is, the higher the position detection accuracy. Thus, in step S15, it is determined whether there is altitude information for three or more points. If there is only altitude information for less than three points, the process returns to step S12 to obtain new altitude information. If there is altitude information for three or more points, the position of device dv1 is detected (step 16), and the process of FIG. 11 ends.

[0070] As described above, in the first embodiment, device dv1 can calculate the distance information to each of devices dv2 to dv4 based on the propagation channel characteristics in order to obtain the information for calculating the distance, the self-coordinate information, and the altitude information from the surrounding devices dv2 to dv4, and can accurately detect the position of device dv1 based on the coordinate information and altitude information of devices dv2 to dv4.

[0071] (Second Embodiment) The second embodiment calculates the position of device dv1 using a processing device such as a server. The second embodiment is mainly assumed for flow line analysis in a factory and for grasping the position of a robot.

[0072] Figures 12A and 12B are diagrams showing signal transmission and reception in a communication system according to the second embodiment. The device dv1 in FIGS. 12A and 12B is a beacon device installed in a moving object such as a specific human or machine, and the devices dv2 to dv4 are communication devices 1 having a communication function with beacon devices or servers (processing devices) installed at various locations. The devices dv1 to dv4 have, for example, the same configuration as that shown in FIG. 2.

[0073] First, as shown in FIG. 12A, in response to requests from the devices dv2 to dv4, the device dv1 transmits information for calculating the distance to the devices dv2 to dv4. The information for calculating the distance is, for example, a single carrier signal as described above. Further, if the device dv1 has the altitude sensor 10, the altitude information measured by the altitude sensor 10 may be included in the information for calculating the distance and transmitted to the devices dv2 to dv4.

[0074] The devices dv2 to dv4 calculate the distance information from the device dv1 based on the above-described propagation channel characteristics. Then, as shown in FIG. 12B, the devices dv2 to dv4 transmit the calculated distance information, self-coordinate information, and altitude information acquired by the altitude sensor 10 to a processing device 20 such as a server. The processing device 20 calculates the position of the device dv1 based on the distance information, self-coordinate information, and altitude information transmitted from the devices dv2 to dv4.

[0075] In FIGS. 12A and 12B, an example of calculating the position of the device dv1 using the devices dv2 to dv4 around the device dv1 is shown. However, even when there are a plurality of devices dv1, the positions of the plurality of devices dv1 can be calculated by the above-described processing procedure using a plurality of devices around each device dv1.

[0076] Note that the specific form of the processing device 20 is not limited. The processing device 20 only needs to have a communication function with the devices dv2 to dv4 and a processing performance for calculating the position of the device dv1, and may be a server, a PC, a tablet, or the like.

[0077] In this way, in the second embodiment, information for calculating the distances from the device dv1 to the devices dv2 to dv4 is transmitted, the distance information from the device dv1 is calculated by the devices dv2 to dv4, and the distance information, self-coordinate information, and altitude information are transmitted from the devices dv2 to dv4 to the server, and the position of the device dv1 is calculated by the processing device 20. Thereby, the processing device 20 such as a server can manage the position of the device dv1. Further, even if the device dv1 does not have the processing performance for calculating the position, the processing device 20 can accurately calculate the position of the device dv1.

[0078] (Third Embodiment) In the third embodiment, a plurality of devices transmit and receive signals to and from each other to calculate the distance information between them, and transmit the calculated distance information to a processing device 20 such as a server.

[0079] FIG. 13 is a block diagram showing a schematic configuration of the processing device 20 according to the third embodiment. The communication device 1 in FIG. 13 includes an antenna 2, a transmission unit 3, a reception unit 4, a distance acquisition unit 61, and a position detection unit 62.

[0080] The distance acquisition unit 61 acquires the distance information calculated by the communication partner device based on the propagation channel characteristics by transmitting and receiving signals to and from the communication partner device. The communication partner device reciprocates signals with other communication partner devices and calculates the distance information from other communication partner devices based on the propagation channel characteristics. The position detection unit 62 detects the position information based on the distance information acquired by the distance acquisition unit 61. The processing device 20 in FIG. 13 may include an altitude sensor 10.

[0081] Figures 14A and 14B are diagrams showing signal transmission and reception in a communication system according to a third embodiment. Devices dv2 to dv5 are, for example, beacon devices and have the same configuration as the communication device 1 in FIG. 2. Hereinafter, an example in which each of the devices dv2 to dv5 includes the altitude sensor 10 will be described. Each of the devices dv2 to dv5 does not need to grasp the absolute coordinates. First, as shown in FIG. 14A, the devices dv2 to dv5 calculate distance information based on the propagation channel characteristics by reciprocating signals between the devices. Thereby, each of the devices dv2 to dv5 can calculate the relative coordinates.

[0082] Next, as shown in FIG. 14B, the devices dv2 to dv5 transmit the calculated distance information and altitude information to a processing device 20 such as a server. The processing device 20 has the configuration shown in FIG. 13 and can create a relative position map of the devices dv2 to dv5 based on the distance information and altitude information transmitted from the devices dv2 to dv5.

[0083] FIG. 15 is a flowchart showing the processing operation of the processing device 20 such as a server in FIG. 14B. First, the processing device 20 acquires the altitude information transmitted from the devices dv2 to dv5 (step S21) and acquires the distance information (step S22).

[0084] Next, the processing device 20 determines whether or not distance information of three or more points has been acquired (step S23). If less than three points of distance information have been acquired, the processing after step S22 is performed. When it is determined that distance information of three or more points has been acquired, the processing device 20 determines whether or not altitude information of three or more points has been acquired (step S24). If less than three points of distance information have been acquired, the processing after step S21 is performed. When it is determined that distance information of three or more points has been acquired, the processing device 20 creates a three-dimensional map (step S25).

[0085] The three-dimensional map is a map that includes the relative position information of devices dv2 to dv5. Note that as described later, when the processing device 20 can obtain the absolute position (coordinate) coordinates of one or more points, a three-dimensional map including the absolute position (coordinate) information of devices dv2 to dv5 can be created.

[0086] As described above, in the third embodiment, by reciprocating signals between devices dv2 to dv5, each device can calculate relative distance information based on the propagation channel characteristics. Further, by transmitting distance information and altitude information from devices dv2 to dv5 to the processing device 20, the processing device 20 can create a three-dimensional map.

[0087] (Fourth Embodiment) In the first to third embodiments described above, a method for positioning one or more devices has been described. Hereinafter, specific application examples will be described.

[0088] FIG. 16 is a plan layout diagram showing an example in which beacon devices are installed at multiple locations indoors. The black triangle marks in FIG. 16 are reference beacon devices 39a with fixed installation positions. The white triangle marks are beacon devices 39b whose installation locations can be changed. In this embodiment, even if the installation location of the beacon device 39b is changed, the positions of the beacon devices 39b can be detected by the distance information calculated based on the propagation channel characteristics by reciprocating signals between the beacon devices 39b or between the beacon device 39b and the reference beacon device 39a.

[0089] The detection of the positions of the beacon devices 39b can be performed by a processing device 20 such as a server that acquires the distance information and altitude information from each beacon device 39a and each reference beacon device 39b.

[0090] FIG. 17 is a flowchart showing a first example of the processing operation of the communication system according to the fourth embodiment. First, it is determined whether it is in the calibration mode (step S31). The calibration mode refers to a mode in which the processing device 20 performs a process of updating the positions of the respective beacon devices 39b. The processing device 20 may shift to the calibration mode when power is turned on or at the time of reset, may shift to the calibration mode when there is an explicit instruction from the user, or may shift to the calibration mode at predetermined time intervals or irregularly.

[0091] If it is determined in step S31 that it is not in the calibration mode, each beacon device 39b and the processing device 20 operate in the normal mode (step S32). The normal mode is a mode in which distance information is calculated or acquired between the moving body.

[0092] If it is determined in step S31 that it is in the calibration mode, ranging is started by reciprocating signals between the respective beacon devices 39b or between the beacon device 39b and the reference beacon device 39a, and relative distance information is calculated based on the propagation channel characteristics (step S33). The calculated distance information is transmitted to the processing device 20 (step S34). Further, when each beacon device 39b is provided with the altitude sensor 10, altitude information is transmitted to the processing device 20.

[0093] Next, the processing device 20 starts the positioning calculation of each beacon device 39b based on the distance information and the altitude information (step S35). Based on the result of the positioning calculation, the processing device 20 updates the position information of each beacon device 39b (step S36).

[0094] When updating the position information of each beacon device 39b, the updated coordinate information may be directly transmitted to each beacon device 39b, or the processing device 20 may have a database in which the position (coordinate) information of each beacon device 39b is registered, and the processing device 20 may manage the positions of each beacon device 39b.

[0095] Further, each beacon device 39b may transmit information other than distance information and altitude information, such as battery remaining information, to the processing device 20. When each beacon device 39b transmits battery remaining information to the processing device 20, the processing device 20 can manage the battery state of each beacon device 39b, and can prompt an operator or the like to replace the battery before the battery runs out.

[0096] In FIG. 16, an example including the reference beacon device 39a with a fixed installation location was described. However, the reference beacon device 39a may be able to acquire absolute position (coordinate) information. Although it is difficult to acquire GPS signals indoors, it is often possible to acquire them near a window. Therefore, as shown in FIG. 18, the reference beacon device 39a may be installed near the window 40 to acquire absolute position information. If the reference beacon device 39a capable of acquiring absolute position information is included among the plurality of beacon devices 39b and the reference beacon device 39a, all the beacon devices 39b and the reference beacon device 39a can acquire absolute position information.

[0097] FIG. 19 is a flowchart showing a second example of the processing operation of the communication system according to the fourth embodiment. The flowchart of FIG. 19 is obtained by adding step S37 to the flowchart of FIG. 17. Step S37 is performed when it is determined in step S31 that the calibration mode is on. In step S37, the reference beacon device 39a receives a GPS signal and acquires absolute position information. Thereafter, by performing the processing of steps S33 to S36, the processing device 20 can update the absolute position information of each beacon device 39b.

[0098] As described above, in the fourth embodiment, the plurality of beacon devices 39b reciprocate signals and transmit the distance information calculated based on the propagation channel characteristics to the processing device 20, so that the processing device 20 can update the positions of the respective beacon devices 39b.

[0099] (Fifth Embodiment) The fifth embodiment evaluates the reliability of the calculated value of the distance information.

[0100] FIG. 20A shows an example where devices dv1 and dv2 are provided at the same altitude, and FIG. 20B shows an example where the altitudes of devices dv1 and dv2 are different. For example, in FIG. 20A, assume that the distance A between devices dv1 and dv2 is calculated to be 5 m. Also, in FIG. 20B, assume that the distance A is calculated to be 5 m and the altitude difference B is detected as 3 m by altitude sensor 10. In this case, the horizontal distance C between devices dv1 and dv2 is calculated to be 4 m by the Pythagorean theorem.

[0101] Thus, if altitude information is obtained, the angle and the horizontal distance can be obtained using only two devices. Using this information, the reliability of the calculated distance information can be set.

[0102] FIG. 21 is a flowchart showing a first example of the processing operation of the communication system according to the fifth embodiment. This flowchart is executed by a processing device 20 such as a server. First, for example, signals are reciprocated between a plurality of devices, and distance information is acquired based on the propagation channel characteristics (step S41). Next, altitude information from each device is acquired, and based on the acquired altitude information and distance information, the angle and the horizontal distance between two devices are calculated (step S42).

[0103] Next, it is determined whether the angle and the horizontal distance calculated in step S42 are within a reasonable range (step S43). If it is determined that the values are within a reasonable range, it is determined that the acquired distance information is highly reliable (step S44). On the other hand, if it is determined that the values are not within a reasonable range, it is determined that the acquired distance information is low in reliability (step S45).

[0104] For example, if the calculated distance information is within 3 m despite the altitude being detected as 3 m by altitude sensor 10, the horizontal distance would be 0 m or less, so it is determined to be low in reliability. Also, if the angle is calculated to be 90 degrees even though there are no multiple devices arranged in the vertical direction, it is also determined to be low in reliability.

[0105] In this way, by treating the altitude information as highly accurate known information, the validity of the distance information calculated based on the propagation channel characteristics can be simply and accurately determined.

[0106] FIG. 22 is a flowchart showing a second example of the processing operation of the communication system according to the fifth embodiment. This flowchart is also executed by a processing device 20 such as a server. First, distance information of four or more points is acquired (step S51). Next, altitude information of four or more points is acquired (step S52). Next, among the altitude information acquired in step S52, three points with adjacent altitude information are selected (step S53). Next, a position is calculated based on the distance information of four or more points and the altitude information of the selected three points (step S54).

[0107] In step S53, three points with adjacent altitude information are selected from among a large number of altitude information. The reason for this is that the closer the altitude values are, the larger the ratio of the horizontal distance to the distance between two points becomes, and the distance between two points can be calculated with higher accuracy.

[0108] In this way, in the fifth embodiment, by using altitude information, the reliability of the distance information calculated based on the propagation channel characteristics can be simply and accurately determined.

[0109] (Sixth Embodiment) In the above-described first to fifth embodiments, as a specific method for calculating distance information based on propagation channel characteristics, a method for calculating distance information by a phase-based method has been mainly described. However, distance information may be calculated by a method other than the phase-based method. For example, it is also conceivable to calculate distance information using UWB. In UWB, a predetermined frequency range is divided into a plurality of sub-bands, a multi-band signal is transmitted, and the propagation delay time of the signal between the transmitter 3 and the receiver 4 is estimated. The distance between the transmitter 3 and the receiver 4 can be calculated from the propagation delay time.

[0110] Note that the present technology can adopt the following configuration. (1) A distance acquisition unit that acquires distance information calculated based on propagation channel characteristics, and an altitude acquisition unit that acquires altitude information, a communication device. (2) The communication device according to (1), further comprising a communication unit that transmits the distance information and the altitude information to a processing device. (3) The communication device according to (1) or (2), wherein the distance acquisition unit acquires the distance information calculated from the relationship between the frequencies and phases of a plurality of propagation channels. (4) The communication device according to (1) or (2), wherein the distance acquisition unit directly acquires the distance information from the measured phase calculated based on the group delay calculated from the relationship between the frequencies and phases of a plurality of propagation channels. (5) The communication device according to (1) or (2), wherein the distance acquisition unit acquires the distance information based on a radio signal in the UWB (Ultra WideBand) band. (6) The communication device according to (3) to (5), wherein the altitude acquisition unit acquires the altitude information based on the atmospheric pressure detected by an atmospheric pressure sensor. (7) The communication device according to (6), wherein the altitude acquisition unit acquires the altitude information based on the atmospheric pressure detected by the atmospheric pressure sensor and the temperature detected by a temperature sensor. (8) A distance acquisition unit that acquires a plurality of distance information calculated from the relationship between the frequencies and phases of a plurality of propagation channels, an altitude acquisition unit that acquires altitude information by communication, and a position detection unit that detects position information based on the distance information and the altitude information, a processing device. (9) The distance acquisition unit acquires three or more pieces of the distance information regarding the distances between the object and three or more communication partner devices, and the position detection unit according to (8), wherein the position detection unit detects the position of the object based on the three or more pieces of distance information and the altitude information. (10) The altitude acquisition unit acquires three or more pieces of the altitude information from the three or more communication partner devices, and the position detection unit according to (9), wherein the position detection unit detects the position of the object based on the three or more pieces of distance information and the three or more pieces of altitude information. (11) The distance acquisition unit calculates distance information between the object and the three or more communication partner devices by having the object transmit and receive wireless signals of a plurality of frequencies with the three or more communication partner devices to calculate a phase, The position detection unit detects the position of the object based on the three or more pieces of distance information calculated by the distance acquisition unit and the three or more pieces of altitude information, the processing device according to (10). (12) The distance acquisition unit acquires the three or more pieces of distance information calculated by the three or more communication partner devices by having the object communicate with the three or more communication partner devices, The position detection unit detects the position of the object based on the three or more pieces of distance information acquired by the distance acquisition unit and the three or more pieces of altitude information, the processing device according to (10). (13) The position detection unit creates a three-dimensional map indicating position information in a predetermined three-dimensional space based on the distance information, the processing device according to (11) or (12). (14) The distance acquisition unit acquires three or more pieces of the distance information between the object and three or more communication partner devices, The position detection unit creates the three-dimensional map based on the three or more pieces of distance information, the processing device according to (13). (15) The three-dimensional map includes the position information of the object and the three or more communication partner devices, the processing device according to (14). (16) The distance acquisition unit acquires three or more pieces of the distance information regarding the distance between the object and three or more communication partner devices, The altitude acquisition unit acquires three or more pieces of the altitude information from the three or more communication partner devices, The position detection unit creates the three-dimensional map based on the three or more pieces of distance information and the three or more pieces of altitude information, the processing device according to (15). (17) A distance acquisition unit that acquires a plurality of pieces of distance information calculated from the relationship between the frequencies and phases of a plurality of propagation channels, A position acquisition unit that acquires absolute position information of at least one point, A processing device comprising a position information detection unit that detects position information based on the plurality of distance information and the absolute position information acquired by the position acquisition unit. (18) The position acquisition unit acquires the absolute position information periodically or irregularly. The position detection unit updates the position information based on the absolute position information acquired periodically or irregularly by the position acquisition unit, the processing device according to (17). (19) Further comprising an altitude acquisition unit that acquires altitude information by communication. The position detection unit detects the position information based on the plurality of distance information, the absolute position information, and the altitude information, the processing device according to (17) or (18). (20) The altitude information includes altitude difference information regarding the altitude difference between two points. Further comprising a reliability estimation unit that estimates the reliability of the distance information based on the distance information and the altitude difference information, the processing device according to (19). (21) A communication device according to any one of (3) to (5), further comprising a position acquisition unit that acquires absolute position information of at least one point. (22) The position acquisition unit acquires GPS (Global Positioning System) information, the communication device according to (21). (23) A first communication device. A second communication device that transmits and receives wireless signals to and from the first communication device. A distance acquisition unit that acquires distance information calculated based on propagation channel characteristics. An altitude acquisition unit that acquires altitude information. A communication system comprising a position detection unit that detects position information based on the distance information and the altitude information. (24) Comprising a third communication device that transmits and receives wireless signals to and from the second communication device. The second communication device has the distance acquisition unit and the altitude acquisition unit. The third communication device has the position detection unit. The distance acquisition unit acquires the distance information with the first communication device. The communication system according to (23), wherein the position detection unit detects the position information based on the distance information and the altitude information. (25) Obtaining distance information calculated based on propagation channel characteristics, obtaining altitude information, A communication method for detecting position information based on the distance information and the altitude information.

[0111] Aspects of the present disclosure are not limited to the individual embodiments described above, but also include various modifications that can be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the content described above. That is, various additions, changes, and partial deletions are possible without departing from the conceptual ideas and spirit of the present disclosure derived from the content defined in the claims and their equivalents.

Description of Reference Numerals

[0112] 1 Communication device, 2 Antenna, 3 Transmitter, 4 Receiver, 5 Distance acquisition unit, 6 Altitude acquisition unit, 7 Clock generator, 8 Distance calculation unit, 9 Altitude calculation unit, 10 Altitude sensor, 11 Initiator, 12 Reflector, 13 Control unit, 20 Processing device, 30 Interface unit, 31 Low-noise amplifier, 32 Mixer, 33 Band-pass filter, 34 Variable-gain amplifier, 35 BPF, 36 VGA, 37 ADC, 41 Phase measurement unit, 43 RAM, 44 Automatic gain control unit, 61 Distance acquisition unit, 62 Position detection unit

Claims

1. A distance acquisition unit that acquires a plurality of distance information calculated from the relationships of the frequencies and phases of a plurality of propagation channels; A position acquisition unit that acquires absolute position information of at least one point; A position detection unit that detects position information based on the plurality of distance information and the absolute position information acquired by the position acquisition unit; An altitude acquisition unit that acquires altitude information through communication; A reliability estimation unit that estimates the reliability of the distance information based on the distance information and the altitude information including altitude difference information regarding the altitude difference between two points; and The position detection unit detects the position information based on the plurality of distance information, the absolute position information, and the altitude information. A processing device.

2. The position acquisition unit acquires the absolute position information periodically or irregularly, The position detection unit updates the position information based on the absolute position information acquired by the position acquisition unit periodically or irregularly. The processing device according to Claim 1.

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