Distance measuring device and method for setting transmission conditions

Abstract

Provided are a distance measurement apparatus in which confidentiality of transmission is enhanced, and a method for setting a transmission condition.　This distance measurement apparatus includes: a phase acquisition unit for acquiring a first phase from when a signal having a first frequency transmitted by a transmission unit to another device is received by the other device, and a second phase from when a signal having a second frequency transmitted by the transmission unit to the other device is received by the other device; a phase measurement unit for measuring a third phase from when the signal having the first frequency is received from the other device, and a fourth phase from when the signal having the second frequency is received from the other device; a distance measurement unit for measuring a distance on the basis of the first phase and second phase, the first frequency, the third phase and fourth phase, and the second frequency; and a setting unit for randomly setting the transmission order of transmission of the signal having the first frequency by the other device, transmission of the signal having the first frequency by the transmission unit, transmission of the signal having the second frequency by the other device, and transmission of the signal having the second frequency by the transmission unit, and the first frequency and the second frequency.

Description

[Technical field]

[0001] The present invention relates to a distance measuring device and a method for setting transmission conditions. [Background technology]

[0002] Conventionally, there has been a distance measuring device including a first device having a first transceiver that transmits a first known signal corresponding to a first carrier frequency and a second known signal corresponding to a second carrier frequency different from the first carrier frequency, and receives a third known signal corresponding to the first carrier frequency and a fourth known signal corresponding to the second carrier frequency; a second device having a second transceiver that transmits the third known signal and the fourth known signal and receives the first and second known signals; and a calculation unit that calculates a distance between the first device and the second device based on the phases of the first to fourth known signals, wherein the first transceiver and the second transceiver perform a total of four transmissions and receptions, that is, one transmission and reception each of the first and third known signals, and one transmission and reception each of the second and fourth known signals (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-128341 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional distance measuring devices can be applied to smart key entry systems for vehicles and provide countermeasures against so-called relay attacks, but the device on the vehicle and the smart key communicate with each other according to a fixed transmission order and transmission frequency that is determined in advance, so the confidentiality of the communication is insufficient. In other words, the countermeasures against relay attacks are insufficient.

[0005] It is therefore an object of the present invention to provide a distance measuring device and a method for setting transmission conditions that improve the confidentiality of communications. [Means for solving the problem]

[0006] A ranging device according to an embodiment of the present invention includes a transmitting unit that transmits a signal to another device, a receiving unit that receives a signal from the other device, a phase acquisition unit that acquires a first phase when the other device receives a signal of a first frequency transmitted by the transmitting unit to the other device and a second phase when the other device receives a signal of a second frequency transmitted by the transmitting unit to the other device, a phase measurement unit that measures a third phase when the receiving unit receives the signal of the first frequency from the other device and a fourth phase when the receiving unit receives the signal of the second frequency from the other device, a ranging unit that measures the distance to the other device based on the first phase and the second phase acquired by the phase acquisition unit, the first frequency, the third phase and the fourth phase measured by the phase measurement unit, and the second frequency, and a setting unit that randomly sets a transmission order for the transmission of the signal of the first frequency of the other device, the transmission of the signal of the first frequency of the transmitting unit, the transmission of the signal of the second frequency of the other device, and the transmission of the signal of the second frequency of the transmitting unit, and the first frequency and the second frequency. Effect of the Invention

[0007] It is possible to provide a distance measuring device and a method for setting transmission conditions that improve the confidentiality of communication. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a smart key 10 and a vehicle 20 in which distance measuring devices 100A and 100B of an embodiment are mounted, respectively. [Diagram 2] FIG. 1 illustrates a distance measuring device 100A according to an embodiment. [Diagram 3] FIG. 4 is a diagram illustrating an example of setting data. [Figure 4] 1 is a diagram illustrating a communication method for distance measurement executed by distance measuring devices 100A and 100B. FIG. [Diagram 5] FIG. 13 is a diagram showing the relationship between frequency and phase obtained by distance measurement. [Figure 6] 11A and 11B are diagrams illustrating a communication method for distance measurement performed by a modified example of an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment to which the distance measuring device and the transmission condition setting method of the present invention are applied will be described.

[0010] <Embodiment> 1 is a diagram showing a smart key 10 and a vehicle 20 equipped with distance measuring devices 100A and 100B of the embodiment, respectively. As an example, a description will be given here of an embodiment in which the distance measuring device 100A is equipped in the smart key 10 of the vehicle 20, and the distance measuring device 100B is equipped in a smart entry system mounted on the vehicle 20. The distance measuring devices 100A and 100B perform packet communication using BLE (Bluetooth Low Energy (registered trademark)) as an example.

[0011] At least one of the distance measuring device 100A of the smart key 10 and the distance measuring device 100B of the vehicle 20 measures the distance between the smart key 10 and the vehicle 20, and the doors, trunk, etc. of the vehicle 20 are unlocked when the distance measured by the distance measuring device 100A or 100B is an appropriate distance.

[0012] Here, as an example, the distance measuring device 100A of the smart key 10 performs distance measurement and notifies the distance measuring device 100B of the vehicle 20 of the result of the distance measurement. The distance measuring devices 100A and 100B have the same configuration as an example. Therefore, in the following, when there is no need to distinguish between the distance measuring devices 100A and 100B, they will be simply referred to as distance measuring device 100. Of the distance measuring device 100A of the smart key 10 and the distance measuring device 100B of the vehicle 20, the distance measuring device 100B that does not perform distance measurement is an example of another device. Here, as an example, the distance measuring device 100B of the vehicle 20 is an example of another device.

[0013] <Configuration of distance measuring device 100A> 2 is a diagram showing a distance measuring device 100A according to an embodiment. As described above, the distance measuring device 100A of the smart key 10 and the distance measuring device 100B of the vehicle 20 have the same configuration. Here, the distance measuring device 100A that performs distance measurement will be described.

[0014] The ranging device 100A includes an antenna 101, a power amplifier (PA) 110, a low noise amplifier (LNA) 120, an orthogonal modulator (OM) 130, an orthogonal demodulator (ODM) 140, a voltage controlled oscillator (VCO) 150, a phase locked loop (PLL) 155, a codec processing unit 160, and a control device 170.

[0015] The antenna 101 communicates with the antenna 101 of the distance measuring device 100B of the vehicle 20. The antenna 101 is connected to the PA 110 and the LNA 120. In this example, a changeover switch for switching the connection destination of the antenna 101 between the PA 110 and the LNA 120 is omitted.

[0016] The PA 110 is provided between the OM 130 and the antenna 101, and amplifies a modulated signal for transmission input from the OM 130 and outputs the signal to the antenna 101. The PA 110 is an amplifier for transmission.

[0017] The LNA 120 is provided between the antenna 101 and the ODM 140, and amplifies the radio waves received by the antenna 101 with low noise and outputs the amplified signal to the ODM 140. The LNA 120 is an amplifier for reception.

[0018] The OM 130 is an example of a transmission section, and modulates the I / Q signal input from the codec processing section 160 using the high-frequency signal input from the VCO 150, and outputs the modulated signal to the PA 110 for transmission.

[0019] The ODM 140 is an example of a receiving unit, and uses the high-frequency signal input from the VCO 150 to demodulate the received signal output from the LNA 120 to obtain an I / Q signal, and outputs the I / Q signal to the codec processing unit 160.

[0020] The VCO 150 oscillates at a frequency set by the PLL 155. The VCO 150 is capable of oscillating at a plurality of frequencies set by the PLL 155.

[0021] The PLL 155 sets the frequency at which the VCO 150 oscillates. The PLL 155 can set a plurality of frequencies for the VCO 150.

[0022] The codec processing unit 160 includes an ADC (Analog to Digital Converter) and a DAC (Digital to Analog Converter) and performs codec processing. The codec processing unit 160 detects BLE packets, performs address determination processing, and the like. More specifically, the codec processing unit 160 digitally converts (ADC processing) the I / Q signal processed by the ODM 140 and converts it into BLE (registered trademark) packet information. The codec processing unit 160 also generates an I / Q signal (divides into an I signal and a Q signal) from a BLE packet signal (digital signal) input from the control device 170, converts it into analog by DAC processing, and outputs it to the OM 130 as an I / Q signal as a transmission signal.

[0023] The control device 170 includes a main control unit 171, a setting unit 172, a notification unit 173, a switching unit 174, a phase acquisition unit 175, a phase measurement unit 176, a distance measurement unit 177, and a memory 178. The memory 178 is an example of a storage unit. The control device 170 is realized by a microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input / output interface, an internal bus, and the like.

[0024] A main control unit 171, a setting unit 172, a notification unit 173, a switching unit 174, a phase acquisition unit 175, a phase measurement unit 176, and a distance measurement unit 177 are functional blocks showing the functions of a program executed by the control device 170. A memory 178 is a functional representation of the memory of the control device 170.

[0025] The main control unit 171 is a processing unit that controls the processing of the control device 170 , and executes processes other than those executed by the setting unit 172 , the notification unit 173 , the switching unit 174 , the phase acquisition unit 175 , the phase measurement unit 176 , and the distance measurement unit 177 .

[0026] The setting unit 172 randomly sets the transmission order and the first and second frequencies for the transmission of a signal of the first frequency from the ranging device 100A to the ranging device 100B, the transmission of a signal of the first frequency from the ranging device 100B to the ranging device 100A, the transmission of a signal of the second frequency from the ranging device 100A to the ranging device 100B, and the transmission of a signal of the second frequency from the ranging device 100B to the ranging device 100A. The transmission order, the first and the second frequencies represent transmission conditions in the method for setting transmission conditions. The method for setting transmission conditions in the embodiment is a method for setting transmission conditions in the ranging devices 100A and 100B.

[0027] Here, as an example, it is assumed that memory 178 of ranging devices 100A and 100B stores configuration data which randomly sets the order of transmission of a signal of a first frequency from ranging device 100A to ranging device 100B, the transmission of a signal of the first frequency from ranging device 100B to ranging device 100A, the transmission of a signal of a second frequency from ranging device 100A to ranging device 100B, and the transmission of a signal of the second frequency from ranging device 100B to ranging device 100A, as well as the first and second frequencies.

[0028] The memory 178 of the distance measuring devices 100A and 100B stores a plurality of identical setting data, and as an example, the notification unit 173 of the distance measuring device 100A notifies the notification unit 173 of the distance measuring device 100B of an ID (identifier) ​​of the setting data used for distance measurement. The distance measuring device 100B that receives the notification reads out the setting data from the memory 178 using the ID and uses it for communication for distance measurement. In this way, the setting data is shared between the distance measuring devices 100A and 100B.

[0029] The setting unit 172 sets the transmission order and the frequencies by reading the setting data from the memory 178. In this way, the setting unit 172 reading the setting data and setting the transmission order and the frequencies is one form of the setting unit 172 randomly setting the transmission order, the first frequency, and the second frequency.

[0030] The setting unit 172 may randomly determine the transmission order, the first frequency, and the second frequency, and set the determined transmission order, the first frequency, and the second frequency as the transmission order and the frequency of the ranging devices 100A and 100B. To randomly set the transmission order and the frequency, for example, a random number generator, a pseudo-random generator, or the like may be used to randomly set the transmission order and the frequency from among a plurality of frequencies prepared in advance. The plurality of frequencies prepared in advance may be prepared in advance by preparing a plurality of tables in which the order of the frequencies is described, and one of the plurality of tables may be selected and used. Information specifying one of the tables may be shared in BLE packet communication so that the setting units 172 of the ranging devices 100A and 100B can use a common table.

[0031] The notification unit 173 at least notifies the notification unit 173 of the distance measuring device 100B of the ID of the setting data, and notifies the notification unit 173 of the distance measuring device 100B of the vehicle 20 of the result of the distance measurement. For these notifications, BLE packet communication of a frequency different from that for communication for distance measurement is used. For notification, the ID of the setting data, the result of the distance measurement, etc. may be written in the payload of the BLE packet.

[0032] The switching unit 174 switches between a transmission state in which the OM 130 transmits a signal and a reception state in which the ODM 140 receives a signal. In the transmission state, the switching unit 174 enables the PA 110 to amplify the signal, and in the reception state, the switching unit 174 enables the LNA to amplify the signal. When switching between the transmission state and the reception state, the switching unit 174 provides a stabilization time for stabilizing the phase and frequency.

[0033] The phase acquisition unit 175 acquires from the ranging device 100B a first phase P1 when the ranging device 100B receives a signal of a first frequency transmitted by the ranging device 100A, and a second phase P2 when the ranging device 100B receives a signal of a second frequency transmitted by the ranging device 100A. The phase acquisition unit 175 acquires the first phase P1 and the second phase P2 from the ranging device 100B by BLE packet communication of a frequency different from that of communication for ranging. The first phase P1 and the second phase P2 may be written in the payload of a BLE packet.

[0034] The phase measurement unit 176 measures a third phase P3 when the ranging device 100A receives a signal of the first frequency from the ranging device 100B, and a fourth phase P4 when the ranging device 100A receives a signal of the second frequency from the ranging device 100B.

[0035] The distance measuring unit 177 measures the distance between the distance measuring device 100A and the distance measuring device 100B based on the first phase P1 and the second phase P2 acquired by the phase acquisition unit 175, the third phase P3 and the fourth phase P4 measured by the phase measurement unit 176, the first frequency, and the second frequency. The method of distance measurement will be described later.

[0036] The memory 178 stores programs, data, and the like necessary for the main control unit 171, setting unit 172, notification unit 173, switching unit 174, phase acquisition unit 175, phase measurement unit 176, and distance measurement unit 177 of the control device 170 to perform the above-mentioned processes. The memory 178 stores setting data in which the above-mentioned transmission order, and the first and second frequencies are set randomly.

[0037] <Setting data> Fig. 3 is a diagram showing an example of setting data. Fig. 3 shows one piece of setting data among a plurality of pieces of setting data stored in memory 178. The ID of the setting data shown in Fig. 3 is 001.

[0038] The setting data includes a transmission order, a transmitting device, a receiving device, and a frequency. One of the distance measuring devices 100A and 100B becomes a transmitting device, and the other becomes a receiving device, and transmits a signal from the transmitting device to the receiving device. The transmission order indicates the order in which the transmitting devices transmit. As an example, the frequencies shown are f1 to f4. Any one of the frequencies f1 to f4 is an example of a first frequency, and any other one of the frequencies f1 to f4 is an example of a second frequency.

[0039] A plurality of such setting data are created and stored in memory 178, and the notification unit 173 of the distance measuring device 100A notifies the notification unit 173 of the distance measuring device 100B of the ID of the setting data used for communication by the distance measuring devices 100A and 100B. To select one setting data from the plurality of setting data, the ID may be selected in a predetermined order, or the ID may be selected using a random number table or the like.

[0040] Furthermore, when generating a plurality of setting data in advance, when generating each setting data, a process may be performed in which the transmission order is set randomly and the frequency is set randomly from among a plurality of frequencies prepared in advance, for example, using a random number generator, a pseudo-random generator, etc. The setting unit 172 may read out the setting data and set the transmission order and the frequency, and the setting method is as described above.

[0041] 3 shows the setting data with ID 001 among the multiple setting data stored in memory 178, so that the setting data with ID other than 001 has different transmission order and frequency from the setting data shown in FIG. 3. In FIG. 3, as an example, the frequencies are set in the order of f1, f2, f3, and f4, such that the transmission order 1 and 2 is frequency f1, the transmission order 3 and 4 is frequency f2, the transmission order 5 and 6 is frequency f3, and the transmission order 7 and 8 is frequency f4, but this order is an example of the result of randomly setting the frequencies. For this reason, for example, the frequencies may be set in the order of f4, f2, f1, and f3, the frequencies may be set in the order of f2, f4, f3, and f1, or the frequencies may be set in the order of f3, f1, f4, and f2. Furthermore, when ranging devices 100A and 100B transmit and receive at the same frequency (here, any one of f1 to f4), the order in which ranging devices 100A and 100B transmit first can be set in various orders by randomly setting the transmission order.

[0042] <Communication method for distance measurement performed by distance measuring devices 100A and 100B> FIG. 4 is a diagram for explaining a communication method for distance measurement executed by the distance measuring devices 100A and 100B. Here, as an example, it is assumed that the setting unit 172 of the distance measuring device 100A reads and sets setting data with a setting data ID of 001 from the memory 178, and transmits the setting data to the distance measuring device 100B before starting communication for distance measurement. Therefore, the distance measuring devices 100A and 100B share the same setting data before communication for distance measurement. If the setting unit 172 of the distance measuring device 100A reads setting data with a setting data ID other than 001 from the memory 178, the distance measuring devices 100A and 100B will execute communication for distance measurement with a transmission order and a combination of frequencies different from the combination of the transmission order and frequencies shown in FIG. 4. Here, as an example, a case will be explained in which communication is performed according to the setting data with a setting data ID of 001.

[0043] In communication for distance measurement, the distance measuring devices 100A and 100B transmit to each other at the same frequency. More specifically, in communication for distance measurement, when one of the distance measuring devices 100A and 100B transmits a signal at a certain frequency, the other transmits a signal at the same frequency. Such mutual transmission constitutes one communication for distance measurement.

[0044] 4, as an example, in the first communication (1), the ranging device 100A transmits a signal at frequency f1 to the ranging device 100B, and the ranging device 100B transmits a signal at the same frequency f1 to the ranging device 100A. The phase acquisition unit 175 of the ranging device 100A acquires from the ranging device 100B the phase when the ranging device 100B receives the signal at frequency f1 transmitted by the ranging device 100A. In addition, the phase measurement unit 176 of the ranging device 100A measures the phase when the ranging device 100A receives the signal at frequency f1 from the ranging device 100B.

[0045] In the second communication (2), the ranging device 100B transmits a signal at frequency f2 to the ranging device 100A, and the ranging device 100A transmits a signal at the same frequency f2 to the ranging device 100B. The phase measurement unit 176 of the ranging device 100A measures the phase when the ranging device 100A receives the signal at frequency f2 from the ranging device 100B. In addition, the phase acquisition unit 175 of the ranging device 100A acquires from the ranging device 100B the phase when the ranging device 100B receives the signal at frequency f2 transmitted by the ranging device 100A.

[0046] In the third communication (3), the ranging device 100A transmits a signal at frequency f3 to the ranging device 100B, and the ranging device 100B transmits a signal at the same frequency f3 to the ranging device 100A. The phase acquisition unit 175 of the ranging device 100A acquires from the ranging device 100B the phase when the ranging device 100B receives the signal at frequency f3 transmitted by the ranging device 100A. In addition, the phase measurement unit 176 of the ranging device 100A measures the phase when the ranging device 100A receives the signal at frequency f3 from the ranging device 100B.

[0047] In the fourth communication (4), the ranging device 100B transmits a signal at frequency f4 to the ranging device 100A, and the ranging device 100A transmits a signal at the same frequency f4 to the ranging device 100B. The phase measurement unit 176 of the ranging device 100A measures the phase when the ranging device 100A receives the signal at frequency f4 from the ranging device 100B. In addition, the phase acquisition unit 175 of the ranging device 100A acquires from the ranging device 100B the phase when the ranging device 100B receives the signal at frequency f4 transmitted by the ranging device 100A.

[0048] The communication for distance measurement shown in Fig. 4 is a communication in which the frequency and the transmission order are set randomly according to the setting data in which the frequency and the transmission order are set randomly as shown in Fig. 3. While performing distance measurement, the distance measuring devices 100A and 100B continue to perform communication as shown in Fig. 4, the phase measuring unit 176 of the distance measuring device 100A measures the phase when the distance measuring device 100A receives a signal from the distance measuring device 100B, and the phase acquiring unit 175 of the distance measuring device 100A acquires from the distance measuring device 100B the phase when the distance measuring device 100B receives the signal transmitted by the distance measuring device 100A.

[0049] Here, the distance measuring devices 100 and 100B each have their own unique reference clock. However, when the synchronization of the reference clocks of the distance measuring devices 100 and 100B is insufficient, a phase shift occurs in the reference clocks of the distance measuring devices 100 and 100B.

[0050] Furthermore, if the first communication (1) to the fourth communication (4) are repeated at a short period of, for example, about 50 ms, the distance between the ranging devices 100A and 100B can be considered to be the same. In this case, the phase when the ranging device 100B receives the signal of frequency fm transmitted by the ranging device 100A as determined by the phase acquisition unit 175 of the ranging device 100A is φAB. Also, the phase when the ranging device 100A receives the signal of frequency fm from the ranging device 100B as determined by the phase measurement unit 176 of the ranging device 100A is φBA. The frequency fm is, for example, any of the above-mentioned frequencies f1 to f4.

[0051] φAB+φBA is the total phase (phase for the round trip) when round trip communication is performed between distance measuring devices 100A and 100B at frequency f. The phase for the round trip at frequency fm is represented as φ2w. 2w stands for two-way. The phase for the round trip in the first communication (frequency f1) is represented as φ1w1, the phase for the round trip in the second communication (frequency f2) is represented as φ2w2, the phase for the round trip in the third communication (frequency f3) is represented as φ2w3, and the phase for the round trip in the fourth communication (frequency f4) is represented as φ2w4. In addition, the wavelengths at frequencies f1 to f4 are represented as λ1 to λ4, respectively.

[0052] As described above, if the first communication (1) to the fourth communication (4) are repeated in a short cycle of, for example, about 50 ms, the distance between distance measuring devices 100A and 100B during the round-trip communications is considered to be the same, so if the distance between distance measuring devices 100A and 100B in the first communication (1) to the fourth communication (4) is L, the following equations (1) to (4) hold. 2L is the round-trip distance. n is an integer equal to or greater than 1. 2L = (n + φ2w1) × λ1 (1) 2L = (n + φ2w2) × λ2 (2) 2L = (n + φ2w3) × λ3 (3) 2L = (n + φ2w4) × λ4 (4)

[0053] Eliminating n from equations (1) and (2) gives the following equation (5A), which can then be rearranged into equations (5B) to (5D) to find the distance, where c is the speed of light. 2L / λ1-φ2w1=2L / λ2-φ2w2 (5A) 2L(1 / λ2-1 / λ1)=φ2w2-φ2w1 (5B) 2L(f2-f1) / c=φ2w2-φ2w1 (5C) L / c=(1 / 2)×(φ2w2-φ2w1) / (f2-f1) (5D)

[0054] Similarly, by eliminating n from equations (1) and (3), they can be transformed into equation (6). L / c=(1 / 2)×(φ2w3-φ2w1) / (f3-f1) (6)

[0055] Similarly, by eliminating n from equations (1) and (4), they can be transformed into equation (7). L / c=(1 / 2)×(φ2w4-φ2w1) / (f4-f1) (7)

[0056] Equations (5D), (6), and (7) show that the ratio of the phase difference between two phases φ2wm (where m is 1 to 4) and the frequency difference between two frequencies fm corresponds to the ratio of the distance L to the speed of light c.

[0057] Therefore, if the phase difference between the two phases φ2wm is Δφ and the frequency difference between the two frequencies fm is Δf, then equations (5D), (6), and (7) can be expressed as the following equation (8). L / c=(1 / 2)×Δφ / Δf (8)

[0058] FIG. 5 is a diagram showing the relationship between frequency fm and phase φ2wm in distance measurement. If the ratio of distance L and the speed of light c obtained by formulas (5D), (6), and (7) is defined as slope A, B, and C, the slopes A, B, and C can be expressed as shown in FIG. 5. Specifically, the slope A is A=(1 / 2)×Δφ / Δf=(φ2w2-φ2w1) / (f2-f1). The slope B is B=(1 / 2)×Δφ / Δf=(φ2w3-φ2w1) / (f3-f1). The slope C is C=(1 / 2)×Δφ / Δf=(φ2w4-φ2w1) / (f4-f1). Note that only one of the slope A obtained from the two frequencies f1 and f2, the slope B obtained from the two frequencies f1 and f3, and the slope C obtained from the two frequencies f1 and f4 may be obtained. Also, here, a form is described in which the slopes A, B, and C are calculated from two frequencies (f1 and f2, f1 and f3, and f1 and f4). However, it is also possible to use three or more frequencies to calculate a straight line by linear approximation using the least squares method for three or more points given by the frequency fm and the phase φ2wm, and to calculate the slope of the calculated straight line as L / c.

[0059] By multiplying the slope A by the speed of light c, we can find the distance L obtained from the combination of frequencies f1 and f2. By multiplying the slope B by the speed of light c, we can find the distance L obtained from the combination of frequencies f1 and f3. By multiplying the slope C by the speed of light c, we can find the distance L obtained from the combination of frequencies f1 and f4.

[0060] As described above, the ranging devices 100A and 100B share setting data that randomly sets the frequency and transmission order when transmitting signals from the ranging device 100A to the ranging device 100B, and the frequency and transmission order when transmitting signals from the ranging device 100B to the ranging device 100A, and transmit signals between the ranging devices 100A and 100B to perform ranging. Since the frequency and transmission order are set randomly, the confidentiality of the communication is high. This provides sufficient countermeasures against relay attacks.

[0061] Therefore, it is possible to provide distance measuring devices 100A (100) and 100B (100) and a method for setting transmission conditions that improves the confidentiality of communication.

[0062] The OM 130 and ODM 140 of the ranging device 100A transmit and receive signals with the ranging device 100B according to the transmission order and frequency randomly set by the setting unit 172, thereby enabling communication for ranging with high confidentiality to be realized.

[0063] In addition, the system includes a switching unit 174 that switches between the transmission state of OM130 and the reception state of ODM140 according to the transmission order randomly set by the setting unit 172, thereby enabling highly confidential communication for ranging to be achieved while reliably switching between the transmission state and the reception state.

[0064] In addition, since the device includes a notification unit 173 that notifies the distance measuring device 100B of the transmission order and frequency randomly set by the setting unit 172, the transmission order and frequency to be used for distance measuring can be notified, and the transmission order and frequency can be shared between the distance measuring devices 100A and 100B, thereby realizing communication for distance measuring with high confidentiality.

[0065] The device also includes memory 178 for storing setting data in which the transmission order and frequency are set randomly, and the setting unit 172 randomly sets the transmission order and frequency by reading the setting data from memory 178, thereby enabling more confidential communication for ranging to be achieved without communicating the transmission order and frequency.

[0066] <Modification> FIG. 6 is a diagram for explaining a communication method for distance measurement executed by a modification of the embodiment. In addition to the distance measuring devices 100A and 100B, FIG. 6 also shows a distance measuring device 100C. The distance measuring device 100C has the same configuration as the distance measuring devices 100A and 100B. Here, as an example, the distance measuring device 100C performs the same operation as the distance measuring device 100B. That is, the distance measuring device 100C performs the same operation on the distance measuring device 100A as the distance measuring device 100B performs on the distance measuring device 100A. The distance measuring device 100C communicates with the distance measuring device 100A in a transmission order and frequency determined by the same setting data as the setting data used by the distance measuring devices 100A and 100B.

[0067] This allows the distance measuring device 100A to obtain the distance between it and the distance measuring device 100C. Here, the modification has been described in which the distance measuring devices 100A and 100B and the distance measuring devices 100A and 100C use the same setting data, and the distance measuring device 100C performs the same operation on the distance measuring device 100A as the distance measuring device 100B performs on the distance measuring device 100A. However, the setting data used by the distance measuring devices 100A and 100B and the distance measuring devices 100A and 100C may be different. That is, the distance measuring device 100A may independently perform communication with the distance measuring device 100B and communication with the distance measuring device 100C in parallel. Even in this case, the distance measuring device 100A can measure the distance between it and the distance measuring device 100B, and can also measure the distance between it and the distance measuring device 100C.

[0068] The above describes an exemplary embodiment of a ranging device and a method for setting transmission conditions of the present invention. However, the present invention is not limited to the specifically disclosed embodiment, and various modifications and changes are possible without departing from the scope of the claims.

[0069] This international application claims priority to Japanese patent application No. 2021-198604, filed on December 7, 2021, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0070] 100, 100A, 100B range finder 101 Antenna 110 PA 120 LNA 130 OM 140 ODM 150 VCO 155 PLL 160 Codec Processing Unit 170 Control device 171 Main control unit 172 Setting section 173 Notification Department 174 Switching section 175 Phase acquisition section 176 Phase measurement section 177 Ranging section 178 Memory

Claims

1. a transmitter that transmits a packet signal of Bluetooth Low Energy (registered trademark) (BLE) to another device; A receiving unit that receives a BLE packet signal from the other device; a phase acquisition unit that acquires a first phase when the packet signal of a first frequency transmitted by the transmission unit to the other device is received by the other device, and a second phase when the packet signal of a second frequency transmitted by the transmission unit to the other device is received by the other device; a phase measurement unit that measures a third phase when the receiving unit receives the packet signal of the first frequency from the other device, and a fourth phase when the receiving unit receives the packet signal of the second frequency from the other device; a distance measuring unit that measures a distance to the other device based on the first phase and the second phase and the first frequency acquired by the phase acquisition unit, the third phase and the fourth phase measured by the phase measurement unit, and the second frequency; a setting unit that randomly sets a transmission order, the first frequency, and the second frequency, for the transmission of the packet signal of the other device at the first frequency, the transmission of the packet signal of the first frequency by the transmitting unit, the transmission of the packet signal of the other device at the second frequency, and the transmission of the packet signal of the second frequency by the transmitting unit; a storage unit for storing a plurality of setting data in which the transmission order, the first frequency, and the second frequency are set randomly; Notification section and Including, the other device has a plurality of setting data identical to the plurality of setting data, the setting unit randomly sets the transmission order, the first frequency, and the second frequency by reading one of the plurality of setting data from the storage unit; The notification unit notifies the other device of an ID (Identifier) ​​of the one piece of setting data.

2. The ranging device of claim 1 , wherein the transmitting unit and the receiving unit transmit and receive the packet signal between the other device and the other device in accordance with the transmission order and the first and second frequencies randomly set by the setting unit.

3. The distance measuring device according to claim 1 , further comprising a switching unit that switches between a transmission state of the transmitting unit and a receiving state of the receiving unit in accordance with the transmission order that is randomly set by the setting unit.

4. the other devices are multiple, the transmitting unit and the receiving unit are capable of transmitting and receiving the packet signals to and from the plurality of other devices, respectively; the phase acquisition unit acquires a plurality of first phases when the other devices receive the packet signal of the first frequency transmitted by the transmission unit to the other devices, and a plurality of second phases when the other devices receive the packet signal of the second frequency transmitted by the transmission unit to the other devices, the phase measurement unit measures the third phases when the receiving unit receives the packet signals of the first frequency from the other devices, and the fourth phases when the receiving unit receives the packet signals of the second frequency from the other devices, 2. The ranging device of claim 1, wherein the ranging unit measures the distances to the other devices based on the first phases and the second phases acquired by the phase acquisition unit, the first frequency, the third phases and the fourth phases measured by the phase measurement unit, and the second frequency.

5. the other devices are multiple, the transmitting unit and the receiving unit are capable of transmitting and receiving the packet signals to and from the plurality of other devices, respectively; the phase acquisition unit acquires, independently and in parallel, a plurality of first phases when the plurality of other devices receive the packet signal of the first frequency transmitted by the transmission unit to the plurality of other devices, and a plurality of second phases when the plurality of other devices receive the packet signal of the second frequency transmitted by the transmission unit to the plurality of other devices, by using different setting data for each of the plurality of other devices; the phase measurement unit measures the third phases when the receiving unit receives the packet signals of the first frequency from the other devices and the fourth phases when the receiving unit receives the packet signals of the second frequency from the other devices independently and in parallel using different setting data for each of the other devices; The ranging device of claim 1, wherein the ranging unit measures the distances to the multiple other devices independently and in parallel using different setting data for each of the multiple other devices based on the multiple first phases and the multiple second phases acquired by the phase acquisition unit, the first frequency, the multiple third phases and the multiple fourth phases measured by the phase measurement unit, and the second frequency.

6. a transmitter that transmits a packet signal of Bluetooth Low Energy (registered trademark) (BLE) to another device; A receiving unit that receives a BLE packet signal from the other device; a phase acquisition unit that acquires a first phase when the packet signal of a first frequency transmitted by the transmission unit to the other device is received by the other device, and a second phase when the packet signal of a second frequency transmitted by the transmission unit to the other device is received by the other device; a phase measurement unit that measures a third phase when the receiving unit receives the packet signal of the first frequency from the other device, and a fourth phase when the receiving unit receives the packet signal of the second frequency from the other device; a distance measuring unit that measures a distance to the other device based on the first phase and the second phase and the first frequency acquired by the phase acquisition unit, the third phase and the fourth phase measured by the phase measurement unit, and the second frequency; A storage section; Notification section and A method for setting a transmission condition in a distance measuring device, comprising: randomly setting a transmission order of the packet signal of the other device at the first frequency, the packet signal of the transmitting unit at the first frequency, the packet signal of the other device at the second frequency, and the packet signal of the transmitting unit at the second frequency, and the first frequency and the second frequency; the storage unit stores a plurality of setting data in which the transmission order, the first frequency, and the second frequency are set randomly, the other device has a plurality of setting data identical to the plurality of setting data, randomly setting the transmission order, the first frequency, and the second frequency by reading one of the plurality of setting data from the storage unit; The method for setting a transmission condition, wherein the notification unit notifies the other device of an ID (Identifier) ​​of the one piece of setting data.

7. the other devices are multiple, the transmitting unit and the receiving unit are capable of transmitting and receiving the packet signals to and from the plurality of other devices, respectively; the phase acquisition unit acquires, independently and in parallel, a plurality of first phases when the plurality of other devices receive the packet signal of the first frequency transmitted by the transmission unit to the plurality of other devices, and a plurality of second phases when the plurality of other devices receive the packet signal of the second frequency transmitted by the transmission unit to the plurality of other devices, by using different setting data for each of the plurality of other devices; the phase measurement unit measures the third phases when the receiving unit receives the packet signals of the first frequency from the other devices and the fourth phases when the receiving unit receives the packet signals of the second frequency from the other devices independently and in parallel using different setting data for each of the other devices; 7. The method for setting transmission conditions as described in claim 6, wherein the distance measurement unit measures the distances to the multiple other devices independently and in parallel using different setting data for each of the multiple other devices based on the multiple first phases and the multiple second phases acquired by the phase acquisition unit, the first frequency, the multiple third phases and the multiple fourth phases measured by the phase measurement unit, and the second frequency.

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