JP6996141B2 - Distance measurement system - Google Patents

Description

The present disclosure relates to a distance measuring system that detects a distance to a target by transmitting and receiving radio signals of two frequencies.

Conventionally, for example, as disclosed in Patent Document 1, there is a dual frequency CW (Continuous Wave) type ranging system. In a dual-frequency CW distance measuring system, the ranging device alternately transmits signals of frequencies f1 and f2 of two laps, and receives reflected signals of two types of frequencies reflected by the target and returned. .. Then, the distance to the target is calculated based on the difference between the phase difference of the received signal with respect to the signal of the first frequency f1 and the phase difference of the received signal with respect to the transmission signal of the second frequency f2 (hereinafter referred to as the two-frequency phase difference). ..

Japanese Unexamined Patent Publication No. 11-183602

According to the configuration as described above, when the distance to the target is equal to or less than the difference wavelength λd which is the wavelength of the difference frequency Δf which is the difference between the first frequency f1 and the second frequency f2, the distance to the target is determined. Can be measured. For example, when the first frequency f1 = 2428 MHz and the second frequency f2 = 2468 MHz, the difference frequency Δf = 40 MHz and the difference wavelength = 7.5 m. That is, in the above example, when the distance to the target is less than 7 m, the distance to the target can be estimated.

However, since the value of the two-frequency phase difference makes one rotation at the wavelength λd of the difference frequency Δf, if the distance at which the two-frequency phase difference becomes φ is La, the one-way distance from that point is 0.5λd (reciprocating). Every time the distance is λd), the two-frequency phase difference becomes φ. That is, there may be a plurality of distances at which the two-frequency phase difference can be an arbitrary value φ.

Therefore, in a situation where a signal from a target located at a distance of 0.5λd or more from the range measuring device can be received, the range measuring device cannot know the distance to the target. Specifically, in a situation where a signal from a target located at a distance of 0.5λd or more can be received, whether the distance to the target is "La" or "La + n · 0.5λd" (n is a natural number). It becomes impossible to determine whether or not. This is because the two-frequency phase difference has the same value φ in each case.

Therefore, in the general dual-frequency CW method, the transmission power of the radio wave in the ranging device is adjusted so as not to receive the signal from the target existing at a distance of 0.5λd or more. However, even if such measures are taken, it does not necessarily mean that the signal from the target existing at a distance of the difference wavelength λd or more is not received. If a signal from a target located at a distance of 0.5λd or more is accidentally received, it is erroneously determined that the distance to the target is within 0.5λd and corresponds to the two-frequency phase difference. Will end up.

The present disclosure has been made based on this circumstance, and an object thereof is to provide a distance measuring system capable of reducing the risk of erroneously determining the distance to a target.

The first ranging system for achieving the purpose transmits a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency. When the distance measuring device (1) provided with the transmitting unit (11) and the first frequency signal transmitted from the distance measuring device are received, at least a part thereof becomes the same signal sequence as the first frequency signal. When the first response signal is returned at the first frequency and the second frequency signal transmitted from the ranging device is received, at least a part of the second frequency signal has the same signal sequence as the second frequency signal. 2 A distance measuring system including a distance measuring device (2) as a target for returning a response signal at a second frequency, wherein the range measuring device is a first response returned from the distance measuring device. The first phase difference, which is the phase difference between the receiving unit (12) that receives the signal and the second response signal and the first response signal received by the receiving unit with respect to the first frequency signal as the transmission signal, is detected and transmitted. The phase difference detecting unit (132) that detects the second phase difference, which is the phase difference of the second response signal received by the receiving unit with respect to the second frequency signal as a signal, and the first phase difference detected by the phase difference detecting unit. A distance estimation unit (133) that acquires an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference, which is the difference between the second frequency and the second frequency, is provided, and the first frequency and the second frequency are respectively. , The frequency is set to a frequency different from the integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, and the distance estimation unit uses the phase expected value, which is the expected value of the first phase difference according to the estimated distance. , Whether or not the estimated distance is correct is determined by comparing with the actual detection value, which is the first phase difference actually detected by the phase difference detection unit , and the distance to the target is the wavelength of the difference frequency. A table storage unit (M1) that stores a distance correspondence table showing the correspondence between the distance to the target and the expected phase value when the difference frequency is less than half of a certain difference wavelength is provided, and the distance estimation unit is the distance to the target. The minimum distance, which is the distance when is less than half of the difference frequency, is acquired as the estimated distance, and the phase expected value and the actual detection value associated with the minimum distance in the distance correspondence table stored in the table storage unit are used. When is the same, it is determined that the minimum distance as the estimated distance is correct as the distance to the target, and the estimated distance is adopted as the distance to the target .
The second ranging system for achieving the above object transmits a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency. When the distance measuring device (1) provided with the transmitting unit (11) and the first frequency signal transmitted from the distance measuring device are received, at least a part thereof becomes the same signal sequence as the first frequency signal. When the first response signal is returned at the first frequency and the second frequency signal transmitted from the ranging device is received, at least a part of the second frequency signal has the same signal sequence as the second frequency signal. 2 A distance measuring system including a distance measuring device (2) as a target for returning a response signal at a second frequency, wherein the range measuring device is a first response returned from the distance measuring device. The first phase difference, which is the phase difference between the receiving unit (12) that receives the signal and the second response signal and the first response signal received by the receiving unit with respect to the first frequency signal as the transmission signal, is detected and transmitted. The phase difference detecting unit (132) that detects the second phase difference, which is the phase difference of the second response signal received by the receiving unit with respect to the second frequency signal as a signal, and the first phase difference detected by the phase difference detecting unit. A distance estimation unit (133) for acquiring an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference which is the difference between the first frequency and the second phase difference is provided, and the first frequency and the second frequency are respectively. , The frequency is set to a frequency different from an integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, and the distance estimation unit has a distance to the target less than half of the difference wavelength, which is the wavelength of the difference frequency. The minimum distance, which is the distance in the case, is acquired as the estimated distance, and the phase expected value, which is the expected value of the first phase difference according to the estimated distance, and the actual first phase difference, which is actually detected by the phase difference detection unit. Whether or not the estimated distance is correct is determined by comparing with the detected value, and the phase expectation that calculates the phase expected value according to the estimated distance based on the minimum distance as the estimated distance and the first frequency. A value calculation unit (134) is provided, and the distance estimation unit determines that the minimum distance as an estimated distance is the distance to the target when the phase expected value calculated by the phase expected value calculation unit and the actual detected value match. It is characterized in that it is determined to be correct and the estimated distance is adopted as the distance to the target.

In the above configuration, the first frequency is set to a frequency different from an integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency. With such a setting, the expected phase values at each distance that provide the same two-frequency phase difference will be different. For example, when the minimum distance at which the two-frequency phase difference is an arbitrary value is La, the phase expected value when the distance is La and the distance is La + 0.5λd (λd is the wavelength of the difference frequency). The value is different from the expected phase value of. Therefore, it is possible to determine whether or not the estimated distance is correct by comparing the first phase difference as the actual detected value with the expected phase value corresponding to the estimated distance.

According to such a configuration, even if the distance measuring device receives a signal from a target located at a point separated from the distance measuring device by 0.5λd or more, the distance to the target is “La”. It can be determined whether it is "La + n × 0.5λd" (n is a natural number). That is, by receiving the signal from the target located at a distance of 0.5λd or more from the distance measuring device, it is possible to reduce the risk of erroneously determining the distance to the target.

Further, the third ranging system for achieving the above object uses a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency. At the same time as transmitting, the first feedback signal, which is a signal in which the first frequency signal is reflected by the target and returned, and the second feedback signal, which is a signal in which the second frequency signal is reflected by the target and returned, are received. A distance measuring system including a distance measuring device (1) for estimating the distance to the target, wherein the distance measuring device includes a transmission unit (11) for transmitting a first frequency signal and a second frequency signal, and a first. The first phase difference, which is the phase difference between the receiving unit (12) for receiving the feedback signal and the second feedback signal, and the first frequency signal as the transmission signal and the first feedback signal received by the receiving unit, is detected, and the first phase difference is detected. The phase difference detection unit (132) that detects the second phase difference, which is the phase difference between the second frequency signal as the transmission signal and the second feedback signal received by the reception unit, and the first place detected by the phase difference detection unit. A distance estimation unit (133) that acquires an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference that is the difference between the phase difference and the second phase difference is provided, and the first frequency and the second frequency are Each is set to a frequency different from an integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, and the distance estimation unit is a phase expected value which is an expected value of the first phase difference according to the estimated distance. And the actual detection value, which is the first phase difference actually detected by the phase difference detection unit, is compared to determine whether or not the estimated distance is correct , and the distance from the target is the wavelength of the difference frequency. It is provided with a table storage unit (M1) that stores a distance correspondence table showing the correspondence relationship between the distance to the target and the phase expected value when the difference frequency is less than half of the difference wavelength, and the distance estimation unit is the same as the target. The minimum distance, which is the distance when the distance is less than half of the difference wavelength, is acquired as the estimated distance, and the phase expected value and the actual detection value associated with the minimum distance in the distance correspondence table stored in the table storage unit are obtained. When the above is the same, it is determined that the minimum distance as the estimated distance is correct as the distance to the target, and the estimated distance is adopted as the distance to the target .
The fourth ranging system for achieving the above object transmits a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency. At the same time, by receiving the first feedback signal, which is a signal in which the first frequency signal is reflected by the target and returned, and the second feedback signal, which is a signal in which the second frequency signal is reflected and returned by the target, respectively. A distance measuring system including a distance measuring device (1) for estimating a distance to a target, wherein the distance measuring device includes a transmission unit (11) for transmitting a first frequency signal and a second frequency signal, and a first feedback signal. The first phase difference, which is the phase difference between the receiving unit (12) that receives the second feedback signal and the first frequency signal as the transmission signal and the first feedback signal received by the receiving unit, is detected, and the transmission signal is detected. The phase difference detecting unit (132) that detects the second phase difference, which is the phase difference between the second frequency signal and the second feedback signal received by the receiving unit, and the first phase difference detected by the phase difference detecting unit. It is provided with a distance estimation unit (133) that acquires an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference that is the difference of the second phase difference, and the first frequency and the second frequency are respectively. When the frequency is set to a frequency different from an integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, and the distance to the target is less than half of the difference wavelength, which is the wavelength of the difference frequency. The minimum distance, which is the distance of, is acquired as the estimated distance, and the phase expected value, which is the expected value of the first phase difference according to the estimated distance, and the actual detection, which is the first phase difference actually detected by the phase difference detector. It is determined whether or not the estimated distance is correct by comparing with the value, and the phase expected value for calculating the phase expected value according to the estimated distance based on the minimum distance as the estimated distance and the first frequency. A calculation unit (134) is provided, and the distance estimation unit sets the minimum distance as the estimated distance as the distance to the target when the phase expected value calculated by the phase expected value calculation unit and the actual detected value match. It is characterized in that it is determined to be correct and the estimated distance is adopted as the distance to the target.

Also in the above configuration, as in the first disclosure, the first frequency is set to a frequency different from an integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency. Therefore, according to such a configuration, it is possible to reduce the possibility of erroneously determining the distance to the target by comparing the expected phase value and the actual detected value.

Further, the fifth distance measuring system for achieving the above object uses a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency. The distance between the distance-measured side device (2) as a target to be sequentially transmitted and the distance-measured side device is estimated by receiving the first frequency signal and the second frequency signal transmitted from the distance-measured side device. A distance measuring system including a distance measuring device (1), a synchronized time information holding unit (135) that holds time information synchronized with the distance measured side device, and a first frequency signal transmitted from a target. Based on the time information held by the receiving unit (12) that receives the second frequency signal and the synchronization time information holding unit, the receiving unit receives the first frequency signal after the distance-measured device transmits the first frequency signal. The first phase difference, which is the phase difference generated until the first frequency signal is received, is acquired, and the second frequency signal is received by the receiving unit after the measured distance side device transmits the second frequency signal. The phase difference detection unit (132) that detects the second phase difference, which is the difference in phase that has occurred until then, and the two-frequency phase difference, which is the difference between the first phase difference and the second phase difference detected by the phase difference detection unit. A distance estimation unit (133) that calculates an estimated value of the distance to the target as an estimated distance based on the above, and the first frequency and the second frequency are differences between the first frequency and the second frequency, respectively. The frequency is set to a frequency different from an integral multiple of the frequency, and the distance estimation unit has the phase expected value, which is the expected value of the first phase difference according to the estimated distance, and the first position actually detected by the phase difference detection unit. Whether or not the estimated distance is correct is determined by comparing with the actual detection value which is the phase difference, and the distance from the target is less than half of the difference frequency which is the wavelength of the difference frequency. A table storage unit (M1) for storing a distance correspondence table showing a correspondence relationship between a distance and a phase expected value is provided, and the distance estimation unit is a distance when the distance to the target is less than half of the difference frequency. When the minimum distance is acquired as the estimated distance and the phase expected value associated with the minimum distance and the actual detected value match in the distance correspondence table stored in the table storage unit, the minimum as the estimated distance. It is characterized in that the distance is determined to be correct as the distance to the target, and the estimated distance is adopted as the distance to the target .
The sixth ranging system for achieving the above object sequentially transmits a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency. Distance measurement that estimates the distance between the distance-measured side device (2) as the target to be measured and the distance-measured side device by receiving the first frequency signal and the second frequency signal transmitted from the distance-measured side device. A ranging system including the device (1), the synchronized time information holding unit (135) that holds the time information synchronized with the device on the distanced side, and the first frequency signal and the first frequency signal transmitted from the target. Based on the time information held by the receiving unit (12) that receives the two-frequency signal and the synchronization time information holding unit, the distance-measured side device transmits the first frequency signal, and then the receiving unit performs the first. While acquiring the first phase difference which is the phase difference generated until the frequency signal is received, from the transmission of the second frequency signal by the distance-measured side device to the reception of the second frequency signal by the receiving unit. Based on the phase difference detection unit (132) that detects the second phase difference, which is the difference in phase generated in, and the two-frequency phase difference, which is the difference between the first phase difference and the second phase difference detected by the phase difference detection unit. It also has a distance estimation unit (133) that calculates the estimated value of the distance to the target as the estimated distance, and the first frequency and the second frequency are the difference frequencies that are the difference between the first frequency and the second frequency, respectively. The frequency is set to a frequency different from an integral multiple, and the distance estimation unit acquires the minimum distance, which is the distance when the distance to the target is less than half of the difference wavelength, which is the wavelength of the difference frequency, as the estimated distance. Whether or not the estimated distance is correct by comparing the phase expected value, which is the expected value of the first phase difference according to the estimated distance, with the actual detected value, which is the first phase difference actually detected by the phase difference detection unit. A phase expectation value calculation unit (134) for calculating a phase expected value according to the estimated distance based on the minimum distance as an estimated distance and the first frequency is provided, and the distance estimation unit is a phase. When the phase expected value calculated by the expected value calculation unit and the actual detected value match, it is determined that the minimum distance as the estimated distance is correct as the distance to the target, and the estimated distance is used as the distance to the target. It is characterized by being adopted.

Also in the above configuration, the first frequency is set to a frequency different from an integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, as in the first and second disclosures. Therefore, according to such a configuration, it is possible to reduce the possibility of erroneously determining the distance to the target by comparing the expected phase value and the actual detected value.

The reference numerals in parentheses described in the claims indicate, as one embodiment, the correspondence with the specific means described in the embodiments described later, and limit the technical scope of the present disclosure. is not it.

It is a block diagram which shows the schematic structure of the ranging system 100 of 1st Embodiment. It is a conceptual diagram for demonstrating the structure of the distance correspondence table. It is a flowchart for demonstrating the distance measurement calculation processing performed by the distance measurement side control unit 13 of 1st Embodiment. It is a flowchart for demonstrating the distance measurement calculation processing performed by the distance measurement side control unit 13 of the 2nd Embodiment. It is a block diagram which shows the structure of the distance measuring side control part 13 of the modification 1. FIG. It is a figure for demonstrating the operation of the ranging system 100 of the modification 2. FIG. It is a block diagram which shows the schematic structure of the ranging system 100 of 3rd Embodiment. It is a block diagram which shows the schematic structure of the ranging system 100 of 4th Embodiment.

[First Embodiment]
Hereinafter, the first embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a diagram showing an example of a schematic configuration of a distance measuring system 100 according to the present embodiment. As shown in FIG. 1, the distance measuring system 100 includes a distance measuring device 1 and a distance measuring side device 2.

The distance measuring device 1 is a device that estimates the distance L from the distance measured side device 2 as a target by a method using a dual frequency CW method. The distance measuring device 1 can be mounted on a moving body such as a vehicle, or installed at an arbitrary position (for example, along a road or near the entrance / exit of a facility) for use. Here, as an example, it is assumed that the distance measuring device 1 is mounted on a vehicle.

The distance-measured side device 2 is, for example, a communication device (so-called mobile terminal) carried by a user of a vehicle equipped with the range-finding device 1. That is, a mobile terminal such as a smartphone, a tablet terminal, a wearable device, a portable music player, a portable game machine, or a portable device for a vehicle can be adopted as the distance-measured side device 2. The vehicle portable device here refers to a communication device that is associated with the vehicle and functions as a key for controlling the locking / unlocking of the door of the vehicle by performing wireless communication with the vehicle.

When the distance measuring device 1 is mounted on a vehicle and the distance measured side device 2 is a mobile terminal carried by a user as in the present embodiment, the distance measuring system 100 of the present disclosure is a vehicle. It functions as a system for estimating the distance L between the user and the user. Further, if the distance measuring device 1 is installed at the entrance of the user's home and the distance measured side device 2 is a mobile terminal carried by the user, the distance measuring system 100 of the present disclosure is: It functions as a system for estimating the distance L between the home entrance and the user.

As another aspect, the distance-measured side device 2 may be mounted on a moving body such as a vehicle. However, if both the distance measuring device 1 and the distance measured side device 2 are mounted on the moving body, it is assumed that each of them is mounted on another moving body.

The distance measuring device 1 and the distance measured side device 2 are configured to be capable of direct bidirectional communication using radio waves of predetermined first frequencies f1 and second frequencies, respectively. Specific values of the first frequency f1 and the second frequency f2 may be appropriately designed. However, the first frequency f1 and the second frequency f2 are different frequencies from each other, and both are set to frequencies different from the integral multiple of the difference frequency Δf, which is the difference between the first frequency f1 and the second frequency f2. It is assumed that there is. For example, the first frequency f1 and the second frequency f2 are preferably frequencies separated from a frequency that is an integral multiple of the difference frequency Δf by 1/4 or more of the difference frequency Δf. Here, as an example, the difference frequency Δf is set to 7 MHz, the first frequency f1 = 921 MHz, and the second frequency f2 = 928 MHz.

The range of frequencies that can be regarded as a frequency different from a certain frequency (hereinafter referred to as a reference frequency) is determined by the resolution of the distance measuring system 100 (more specifically, the distance measuring device 1). For example, when the resolution of the ranging device 1 is 100 kHz, a frequency separated from the reference frequency by 100 kHz or more can be regarded as a frequency different from the reference frequency. Therefore, the frequency different from the integral multiple of the difference frequency Δf is a frequency separated from the frequency which is an integral multiple of the difference frequency by the resolution of the frequency of the distance measuring device 1 or more.

As a standard for communication between the distance measuring device 1 and the distance measured side device 2, for example, a predetermined short-range wireless communication standard having a maximum communication range of about several tens of meters can be adopted. The short-range wireless communication standard here is, for example, Bluetooth Low Energy (Bluetooth is a registered trademark), Wi-Fi (registered trademark), and the like. Of course, communication standards other than the above can also be adopted as the communication standard used for communication between the distance measuring device 1 and the distance measured side device 2. Hereinafter, an example of the configuration of the distance-measured side device 2 and the distance-measuring device 1 will be described more specifically.

<About the configuration of the distance measuring device 1>
Here, the configuration of the distance measuring device 1 will be described. As shown in FIG. 1, the distance measuring device 1 includes a distance measuring side transmitting unit 11, a distance measuring side receiving unit 12, and a distance measuring side control unit 13. The ranging side transmitting unit 11 and the ranging side receiving unit 12 are connected to the ranging side control unit 13 so as to be able to communicate with each other. The ranging side transmitting unit 11 and the ranging side receiving unit 12 may be integrally configured as one communication device.

The distance measuring side transmission unit 11 is a communication module that transmits a signal of the first frequency or a signal of the second frequency based on an instruction from the distance measuring side control unit 13. The ranging side transmission unit 11 is configured by using a modulation circuit, an amplification circuit, an antenna, or the like that generates a first frequency signal and a second frequency signal (that is, a carrier wave signal) from a baseband signal. It should be noted that the signal transmission of the first frequency and the second frequency may be realized by using one common antenna, or the antenna for the first frequency and the antenna for the second frequency may be separately provided. ..

The ranging side receiving unit 12 is a communication module for receiving a signal of the first frequency and a signal of the second frequency. The distance measuring side receiving unit 12 is configured by using a demodulation circuit that demodulates a carrier wave signal into a baseband signal, an amplifier circuit, an antenna, and the like. The radio wave of the first frequency and the radio wave of the second frequency may be configured to be received by using one antenna, or the antenna for receiving the radio wave of the first frequency and the radio wave of the second frequency. It may be provided separately as an antenna for receiving the radio wave. When receiving the first frequency radio wave and the second frequency radio wave using one antenna, it is equipped with a filter circuit for separating the first frequency signal and the second frequency signal from the received signal. Just do it. The signal received by the ranging side receiving unit 12 is output to the ranging side control unit 13.

The distance measuring side control unit 13 controls the operation of the distance measuring side transmitting unit 11 and the distance measuring side receiving unit 12, and is based on the reception status of the signal from the distance measuring side device 2 in the distance measuring side receiving unit 12. The configuration is such that the distance L from the distance-measured side device 2 is estimated. For example, the ranging side control unit 13 instructs the ranging side transmitting unit 11 to transmit the response request signal of the first frequency and the response request signal of the second frequency in order at a predetermined cycle. As a result, the ranging side transmission unit 11 transmits the response request signal of the first frequency and the response request signal of the second frequency in a predetermined cycle. The response request signal here is a signal requesting the device 2 on the distance-measured side to return the response signal. A specific signal sequence (in other words, a bit pattern) of the response request signal may be appropriately designed. The response request signal of the first frequency corresponds to the first frequency signal according to the claim, and the response request signal of the second frequency corresponds to the second frequency signal according to the claim.

Then, the distance measuring side control unit 13 estimates the distance L from the distance measuring side device 2 to the distance measuring side device 2 based on the reception status of the response signal by the distance measuring side receiving unit 12 for the response request signal. .. The details of the function of the distance measuring side control unit 13 will be described later.

The distance measuring side control unit 13 is realized by using, for example, a computer. That is, the distance measuring side control unit 13 includes a CPU, RAM, flash memory, and the like. The CPU is an arithmetic processing unit that executes various arithmetic processing. MPU or GPU may be used instead of CPU. RAM is a volatile storage medium and flash memory is a rewritable non-volatile storage medium. The flash memory stores a program (hereinafter referred to as a distance measuring program) for causing a normal computer to function as a distance measuring side control unit 13. As another aspect, the distance measuring side control unit 13 may be realized as hardware by using one or a plurality of ICs.

<About the distance-measured side device 2>
Next, the configuration of the distance-measured side device 2 will be described. As shown in FIG. 1, the distance-measured side device 2 includes a distance-measured side receiving unit 21, a distance-measured side control unit 22, and a distance-measured side transmitting unit 23. The distance-measured side receiving unit 21 is a communication module for receiving a signal of the first frequency and a signal of the second frequency. Since the configuration of the ranging side receiving unit 21 can be the same as that of the ranging side receiving unit 12, detailed description thereof will be omitted. The distance-measured side receiving unit 21 receives a response request signal transmitted by the distance-finding device 1 via an antenna (not shown), performs predetermined processing such as shaping, amplification, and frequency conversion, and is subjected to predetermined processing such as shaping, amplification, and frequency conversion. Output to.

When the distance-measured side receiving unit 21 receives the response request signal of the first frequency, the distance-measured side control unit 22 transmits the first-frequency response signal to the distance-measured side transmitting unit 23. Instruct. Further, when the distance-measured side receiving unit 21 receives the second frequency response request signal, the distance-measured side transmitting unit 23 is instructed to transmit the second frequency response signal. The distance-measured side control unit 22 may be realized by using an MPU, RAM, or the like. The distance-measured side control unit 22 may be realized by using one or a plurality of ICs.

The distance-measured side device 2 of the present embodiment returns a signal having the same signal sequence as the response request signal as a response signal to the response request signal transmitted from the range-finding device 1. It shall be configured. That is, it is assumed that the distance-measured side device 2 is configured to return the same signal as the received response request signal as it is or after amplifying and shaping it.

The distance-measured side transmission unit 23 is a communication module for transmitting a first frequency signal and a second frequency signal based on an instruction from the distance-measured side control unit 22. For example, the distance-measured side transmission unit 23 transmits a response signal of the first frequency based on an instruction from the distance-measured side control unit 22. Further, the response signal of the second frequency is transmitted based on the instruction from the distance-measured side control unit 22. Since the configuration of the distance measuring side transmitting unit 23 can be the same as that of the distance measuring side transmitting unit 11, detailed description thereof will be omitted. The response signal of the first frequency corresponds to the first response signal according to the claim, and the response signal of the second frequency corresponds to the second response signal according to the claim.

In the distance-measured side device 2 configured as described above, a predetermined time is obtained from the time when the distance-measured side receiving unit 21 receives the response request signal to the time when the distance-measured side transmitting unit 23 transmits the response signal. It takes time (hereinafter, response processing time) τ. However, this response processing time τ is determined according to the hardware configuration of the distance-measured side device 2. Therefore, the assumed value of the response processing time τ can be specified in advance by a test or the like. It is assumed that the assumed value of the response processing time τ in the distance-measured side device 2 is registered in advance in the distance-finding device 1 as a part of the distance-finding program.

<About the function of the distance measuring device 1>
Next, the functions provided by the distance measuring side control unit 13 will be described. The distance measuring side control unit 13 has a function corresponding to the functional block shown in FIG. 1 as a function expressed by the CPU executing the distance measuring program. That is, the distance measuring side control unit 13 includes a transmission control unit 131, a phase difference detection unit 132, and a distance estimation unit 133 as functional blocks. Further, the table storage unit M1 is provided as a configuration realized by using a non-volatile storage medium (for example, a flash memory). The table storage unit M1 is data showing the two-frequency phase difference θd, which will be described later, and the expected value (phase expected value) θm of the first phase difference θ1 for each distance L from the distance measuring device 1 to the distanced side device 2. It is a storage device that stores (hereinafter referred to as a distance correspondence table). Details of the distance correspondence table will be described later.

The transmission control unit 131 is configured to perform transmission control of the response request signal described above in cooperation with the distance measuring side transmission unit 11. That is, the transmission control unit 131 transmits the response request signal of the first frequency and the response request signal of the second frequency in order or at the same time in a predetermined cycle. From the viewpoint of temporally leveling the processing load of the distance-measured side device 2, the transmission interval between the response request signal of the first frequency and the response request signal of the second frequency is set by the distance-measured side device 2. It is preferable that the response processing times τ are separated from each other.

When the ranging side receiving unit 12 receives the response signal of the first frequency, the phase difference detecting unit 132 has already transmitted the first, based on the electric signal indicating the response signal input from the ranging side receiving unit 12. The phase difference (hereinafter, the first phase difference) θ1 of the response signal with respect to the response request signal of one frequency is detected. Further, when the ranging side receiving unit 12 receives the response signal of the second frequency, the phase difference detecting unit 132 is based on the electric signal indicating the response signal input from the ranging side receiving unit 12. The phase difference (hereinafter referred to as the second phase difference) θ2 with respect to the response request signal of the second frequency is detected. For the phase difference of the response signal with respect to the response request signal as the transmission signal, for example, the elapsed time from the transmission of the response request signal to the reception of the response signal is counted by a clock signal or the like, and the count value and the carrier wave signal are counted. The phase difference may be determined based on the period of (in other words, the inverse of the frequency). A well-known configuration can be adopted as the configuration for detecting the phase difference.

The distance estimation unit 133 calculates the difference (hereinafter, two-frequency phase difference) θd between the first phase difference θ1 and the second phase difference θ2 provided by the phase difference detection unit 132, and based on the two-frequency phase difference θd. , The configuration is such that an estimated value of the distance L from the distance measuring device 1 to the distance measured side device 2 is acquired (specifically, calculated or read out). In the present embodiment, as an example, the distance estimation unit 133 estimates the distance L using the distance correspondence table stored in the table storage unit M1. That is, the distance estimation unit 133 estimates the distance L by reading the value of the distance L associated with the two-frequency phase difference θd calculated from the phase difference detection unit 132.

As shown in FIG. 2, for example, the distance correspondence table used here is 2 according to the distance L when the distance L is from 0 to 0.5 times the wavelength of the difference frequency Δf (hereinafter, the difference wavelength) λd. A table (in other words, a data set) showing the correspondence between the frequency phase difference θd and the expected value of the first phase difference θ1 to be detected is provided. Further, as a more preferable embodiment, in the distance correspondence table of the present embodiment, the correspondence between the two-frequency phase difference θd corresponding to the distance L when the distance L is larger than 0.5λd and the expected value of the first phase difference θ1. A dataset showing the relationship shall also be provided. The difference wavelength λd is the propagation speed C (3 × 10 ^ 8 m / sec) of the radio wave divided by the difference frequency Δf. 0.5λd is half the length of the difference wavelength λd.

The distance L with respect to the two-frequency phase difference θd when the distance L is between 0 and 0.5λd is determined by Equation 1 below.

Further, the distance L with respect to the two-frequency phase difference θd when the distance L is larger than 0.5λd is 0. It is the value obtained by adding an integral multiple of 5λd. This is because every time the one-way distance increases by 0.5λd, the round-trip distance increases by λd, and each time the round-trip distance increases by λd, the two-frequency phase difference θd makes one circumference (that is, 360 degrees).

Further, the expected value (that is, the expected phase value) θm of the first phase difference θ1 with respect to a certain distance L is determined by substituting the parameter K determined by the following equation 2 into the equation 3.

The parameter K determined by Equation 2 is the remainder (that is, the remainder) obtained by dividing (2L / C + τ) by 1 / f1. The mod in the formula is a symbol having the same meaning as the remainder operator "%" used in C language and the like.

By the way, as shown in FIG. 2, the first frequency f1 is set to a frequency different from an integral multiple of the difference frequency Δf. Therefore, even in the case where the two-frequency phase difference θd makes one rotation or a plurality of rotations and becomes φ again, the expected phase value θm in each case becomes a different value depending on the distance L. For example, even when the two-frequency phase difference θd = φ, the value of the expected phase value θm when the distance L is less than 0.5λd is θa, while the distance L is less than 0.5λd to λd. In this case, the expected phase value θm is θb. When the distance L is less than λd to 1.5λd, the value of the expected phase value θm is θc. Note that θa, θb, and θc all have different values.

In this way, even when the two-frequency phase difference θd is the same value, the phase expected value θm is different depending on the distance L, so that the phase expectation corresponding to the distance L estimated from the two-wavelength phase difference θd By collating the value θm with the actual first phase difference θ1, it is possible to distinguish whether the distance-measured device 2 exists at a distance of 0.5λd or more or within the difference wavelength λd.

<Distance measurement calculation processing>
Next, a series of processes (hereinafter referred to as distance measurement calculation processing) performed by the distance measurement side control unit 13 to estimate the distance L from the distance measurement side device 2 will be described using the flowchart shown in FIG. .. The flowchart shown in FIG. 3 may be performed at a predetermined cycle (for example, every 100 milliseconds). Further, the flowchart of FIG. 3 may be executed triggered by the occurrence of a predetermined event.

First, in step S101, the transmission control unit 131 cooperates with the distance measuring side transmission unit 11 to transmit a response request signal of the first frequency, and the process proceeds to step S102. In step S102, the distance measuring side receiving unit 12 receives the response signal of the first frequency returned from the distance measuring side device 2 and proceeds to step S103. If the response signal from the distance-measured side device 2 is not received even after the predetermined response standby time has elapsed after moving to step S102, the distance-measured side device 2 has the detection area of the range-finding device 1. It is sufficient to consider that it exists outside and end this flow.

The response waiting time may be appropriately designed in a range longer than the response processing time τ. For example, the response standby time may be a value obtained by adding the maximum flight time obtained by dividing the value obtained by doubling the predetermined detection limit distance by the propagation speed C of the radio wave to the response processing time τ. The detection limit distance is a parameter indicating the maximum value of the distance L from the distance-measured side device 2 that can be calculated by the distance-measuring device 1, and is appropriately set as a system requirement. The above-mentioned detection area is a range within the detection limit distance from the distance measuring device 1. In step S103, the phase difference detection unit 132 detects the first phase difference θ1 based on the reception signal of the first frequency input from the distance measuring side receiving unit 12, and proceeds to step S104.

In step S104, the transmission control unit 131 cooperates with the distance measuring side transmission unit 11 to transmit a response request signal of the second frequency, and proceeds to step S105. In step S105, the distance measuring side receiving unit 12 receives the response signal of the second frequency returned from the distance measuring side device 2 and proceeds to step S106. If the response signal from the distance-measured side device 2 is not received even after the predetermined response standby time has elapsed after moving to step S105, this flow may be terminated.

Further, as another embodiment, if the response signal from the distance-measured side device 2 is not received even after the predetermined response standby time has elapsed since the process proceeds to step S105, the response request signal of the second frequency is retransmitted. You may. When the response signal for the response request signal of the second frequency cannot be received even though the response signal for the response request signal of the first frequency can be received, the signal of the second frequency is transmitted and received due to accidental noise. This is because it may have failed.

In step S106, the phase difference detection unit 132 detects the second phase difference θ2 based on the reception signal of the second frequency input from the distance measuring side receiving unit 12, and proceeds to step S107. In step S107, the distance estimation unit 133 calculates the dual frequency phase difference θd by subtracting the second phase difference θ2 from the first phase difference θ1 provided by the phase difference detection unit 132. Then, in the distance correspondence table, the value of the distance L associated with the two-frequency phase difference θd calculated in this step is referred to with reference to the data set when the distance L is a value from 0 to 0.5λd. read out. For example, when the two-frequency phase difference θd is φ, it is estimated that the distance L = α.

In this embodiment, as an example, the distance L is estimated using the distance correspondence table, but the present invention is not limited to this. The distance estimation unit 133 may estimate the distance L by calculating the above-mentioned equation 1. When the estimation of the distance L is completed, the process proceeds to step S108.

In step S108, the distance estimation unit 133 reads the phase expected value θm associated with the distance L estimated in step S107 from the distance correspondence table to acquire the value of the phase expected value θm. For example, when the distance L = α, it is determined that the expected phase value θm = θa. When the process in step S108 is completed, the process proceeds to step S109.

In step S109, it is determined whether or not the first phase difference θ1 actually detected (in other words, observed) in step S103 matches the expected phase value θm acquired in step S108. If the first phase difference θ1 as the actual detected value matches the expected phase value θm, the affirmative determination is made in step S109, and the process proceeds to step S110. On the other hand, if the first phase difference θ1 as the actual detected value does not match the expected phase value θm, step S109 is negatively determined and the process proceeds to step S111.

The match here is not limited to a perfect match. When the first phase difference θ1 as the actual detected value is located within a predetermined error range (for example, within ± 5 degrees) centered on the expected phase value θm, the first phase difference θ1 as the actual detected value is It may be determined that the phase expected value θm corresponding to the estimated distance L is the same. Determining whether or not the first phase difference θ1 as the actual detected value matches the expected phase value θm means that the first phase difference θ1 as the actual detected value is the expected phase value θm according to the estimated distance L. Corresponds to determining whether or not it is consistent with.

In step S110, it is determined that the distance L estimated in step S107 is correct (in other words, it is appropriate), and this flow ends. In this case, the distance L estimated in step S107 is adopted as the distance from the distance measuring device 1 to the distance measured side device 2. On the other hand, in step S111, it is determined that the distance L estimated in step S107 is an error, and this flow ends. In this case, the distance L estimated in step S107 is discarded. That is, the distance L estimated in step S107 is not adopted as the distance from the distance measuring device 1 to the distance measured side device 2.

<Effect of embodiment>
Every time the distance L from the distance-measured device 2 as a target is separated by 0.5λd (every time the reciprocating distance is separated by λd), the two-frequency phase difference θd makes one rotation. Therefore, every time the one-way distance L increases by 0.5λd (every time the round-trip distance increases by λd), the two-frequency phase difference θd becomes the same value. In other words, the points where the two-frequency phase difference θd becomes an arbitrary value φ exist at intervals of 0.5λd (as a round trip distance at intervals of λd). Therefore, in the general dual-frequency CW technology represented by Patent Document 1, if it is allowed to receive a signal from a target located at a distance of 0.5λd or more, the distance L from the target is “α”. It becomes impossible to determine whether it is present or "n × 0.5λd + α" (n is a natural number).

In response to such a problem, in the configuration of the present embodiment, first, the first frequency f1 is set to a frequency different from an integral multiple of the difference frequency Δf. As a result, the expected phase value θm itself becomes a different value according to the distance L even at a plurality of points where the two-frequency phase difference θd makes one rotation or a plurality of rotations and becomes φ again. Then, the distance estimation unit 133 has the phase expected value θm associated with the distance L estimated from the two-frequency phase difference θd when the distance L is assumed to be less than 0.5λd, and the actual detection value. By comparing with the first phase difference θ1 as the above, it is determined whether or not the estimated distance L is correct.

According to such a configuration, even if a signal is received from the distance-measured side device 2 located at a point separated from the distance-finding device 1 by "α + n × 0.5λd" (n is a natural number) or more. It is possible to determine whether the distance to the target is "α" or "α + n × 0.5λd". That is, even if a signal from the distance-measured side device 2 existing at a distance of 0.5λd or more is received, it is possible to identify whether or not the distance-finding object is nearby. Therefore, by receiving the signal from the distance-measured side device 2 existing at a distance of 0.5λd or more, it is possible to reduce the possibility of erroneously determining the distance to the distance-measured side device 2.

Further, the distance estimation unit 133 of the present embodiment determines the validity of the estimated distance L by using a table showing the phase expected value θm corresponding to the distance L prepared in advance. According to such a configuration, the calculation load on the distance measuring side control unit 13 can be reduced. As a result, the responsiveness can be improved.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-mentioned first embodiment, and the second to fourth embodiments described below and various modifications are also the techniques of the present disclosure. It is included in the target range, and can be changed and implemented in various ways within the range other than the following that does not deviate from the gist.

The members having the same functions as those described in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. Further, when only a part of the configuration is referred to, the configuration of the embodiment described above can be applied to the other parts.

[Second Embodiment]
In the first embodiment described above, it is assumed that the distance-measured device 2 exists within 0.5λd from the range-finding device 1, and the estimated distance L from the distance-measured device 2 estimated from the expected phase value θm. We have disclosed a configuration in which the expected phase value θm is used to determine whether or not is correct. On the other hand, if the expected phase value θm corresponding to the distance L is used, the distance L can be estimated even when the distance-measured side device 2 is separated from the distance-finding device 1 by 0.5λd or more. Hereinafter, an embodiment based on such a technical idea will be disclosed below as a second embodiment.

The schematic configuration of the ranging system 100 in the second embodiment is the same as that in the first embodiment. However, the distance measuring side control unit 13 of the second embodiment performs the processing according to the flowchart illustrated in FIG. 4 instead of the flowchart shown in FIG. 3 as the distance measuring calculation processing. The execution conditions of the flowchart shown in FIG. 4 can be the same as the execution conditions of the distance measurement calculation processing in the above-described embodiment.

Since the series of processes from steps S201 to S207 shown in FIG. 4 is the same as the series of processes from steps S101 to S107 shown in FIG. 3, the description thereof will be omitted. However, hereinafter, for convenience, the distance estimated in step S207 will be referred to as the minimum distance La. The distance estimated in step S207 is such that the distance L is the distance in which the two-frequency phase difference θd is a value calculated from the first phase difference θ1 and the second phase difference θ2 (for convenience, the calculated value φ). This is because the distance estimated assuming the case of being between 0 and the difference wavelength λd, that is, the two-frequency phase difference θd is the smallest value among the distances that can be the calculated value φ.

In step S208, the variable parameter N for calculation used in the subsequent processing is set to 0, and the process proceeds to step S209. N is a parameter in which an integer of 0 or more is set. In step S209, the distance estimation unit 133 refers to the distance correspondence data stored in the table storage unit M1 and reads out the phase expected value θm associated with the distance L = La + N · 0.5λd. Since N = 0 when step S209 is performed for the first time after the start of this flow, the phase expected value θm associated with the minimum distance La estimated in step S207 is read out. When the process in step S209 is completed, the process proceeds to step S210.

In step S210, it is determined whether or not the first phase difference θ1 actually detected (in other words, observed) in step S203 matches the expected phase value θm read in step S209. If the first phase difference θ1 as the actual detected value matches the expected phase value θm, affirmative determination is made in step S210, and the process proceeds to step S211. On the other hand, if the first phase difference θ1 as the actual detected value does not match the expected phase value θm, the step S210 is negatively determined and the process proceeds to step S212. It should be noted that the same concept as in step S109 described above can be applied as a criterion for determining whether or not they match.

In step S211 it is determined that the distance L from the distance measuring device 1 to the distance measured side device 2 is La + N · 0.5λd, and this flow ends. On the other hand, in step S212, the distance estimation unit 133 increases (that is, increments) the value of the parameter N by one, and executes step S209 again. The distance of La + N · 0.5λd corresponds to the distance candidate described in the claims.

According to such a configuration, the phase expected value θm when the distance L is La + N · 0.5λd and the first phase difference θ1 as the actual detection value are sequentially compared while incrementing N. The distance associated with the expected phase value θm that matches the detected value is finally adopted as the distance to the distance-measured side device 2.

<Effect of the second embodiment>
As described above, in the general dual-frequency CW technology represented by Patent Document 1, if the signal from the target existing at a distance of 0.5λd or more is allowed to be received, the distance L from the target is “α”. It becomes impossible to determine whether it is "α + n × 0.5λd" (n is a natural number). Therefore, in the general dual-frequency CW technology, the transmission power of the radio wave in the ranging device is adjusted so as not to receive the signal from the target existing at a distance of 0.5λd or more. That is, in other words, the detection limit distance in the general dual-frequency CW technique is set to 0.5λd.

On the other hand, according to the configuration of the second embodiment, even when the distance-measured side device 2 is located at a point separated from the distance-finding device 1 by 0.5λd or more, the distance-measured side device 2 is used. The distance L can be specified. That is, according to the configuration of the present embodiment, the detection limit distance can be set to 0.5λd or more. Further, as a secondary effect, since the relationship between the detection limit distance and the difference frequency Δf is weakened, the degree of freedom in designing the difference frequency Δf can be increased.

[Modification 1]
In the first and second embodiments described above, the distance estimation unit 133 acquires the expected phase value θm according to the estimated distance L by referring to the distance correspondence table stored in the table storage unit M1. , Not limited to this.

For example, as shown in FIG. 5, the distance measuring side control unit 13 may include a phase expected value calculation unit 134 that calculates the phase expected value θm according to the estimated distance L instead of the table storage unit M1. The expected phase value θm according to the distance L can be calculated by using the above-mentioned equations 2 and 3. In the second embodiment, L to be substituted into the equation 2 when obtaining the expected phase value θm may be La + N · 0.5λd. Further, the minimum distance La corresponding to the two-frequency phase difference θd can be calculated by Equation 1.

According to such a configuration, it is not necessary to provide the distance measuring device 1 with a table storage unit M1 in which a distance correspondence table showing the expected phase value θm for each distance L is stored. Further, even if the response processing time τ changes due to a model change of the distance measuring side device 2, the response processing time τ can be dealt with simply by rewriting the value of the response processing time τ registered in the distance measuring side control unit 13. Can be done.

[Modification 2]
When the distance measuring device 1 and the distanced side device 2 are configured to enable bidirectional communication as in the first and second embodiments described above, predetermined information is used as a response request signal or a response signal. It may be configured to send and receive signals including. However, as shown in FIG. 6, a preamble section having a constant signal waveform for notifying the other party that data is to be sent is arranged at the head portion of the response request signal and the response signal. The phase difference detection unit 132 shall detect the phase difference using the preamble section.

According to such a configuration, data communication can be performed at the same time as the distance measurement calculation process. As a result, when the distance measuring device 1 is configured to perform a predetermined service (for example, vehicle control) by communicating with the distance measured side device 2, the service for the user's approach to the vehicle is performed. The responsiveness of the vehicle can be improved. As the modulation method when the distance measuring device 1 and the distance measured side device 2 wirelessly communicate with each other, a well-known modulation method such as AM modulation, ASK modulation, or FSK modulation can be adopted.

[Modification 3]
In the above-described embodiment and the like, the distance estimation unit 133 discloses a configuration in which the validity of the estimated distance L is determined and the distance L is estimated by using the expected value corresponding to the distance L with respect to the first phase difference θ1. However, it is not limited to this. Instead of the expected value of the first phase difference θ1, the validity of the estimated distance L may be determined by using the expected value of the second phase difference θ2, or the distance L may be estimated. The first frequency and the second frequency are interchangeable.

[Third Embodiment]
In the first and second embodiments described above, and various modifications, the distance measuring device 1 and the distance measured side device 2 are configured to communicate in both directions, but the present invention is not limited to this. As shown in FIG. 7, when the synchronized time information holding unit 135 holding the time information synchronized with the time information held by the distance measured side device 2 is provided, the distance measured side device 2 is provided. The distance L can also be estimated by unidirectional communication from the distance measuring device 1 to the distance measuring device 1.

Specifically, the distance-measured side device 2 sequentially transmits a signal of the first frequency and a signal of the second frequency at a predetermined timing. The phase difference detection unit 132 of the distance measuring device 1 has the first phase difference θ1 and the first phase difference θ1 based on the time information held by the synchronization time information holding unit 135 and the received signal input from the distance measuring side receiving unit 12. The second phase difference θ2 is detected.

The time information synchronized with the distance-measured side device 2 held by the synchronization time information holding unit 135 may be registered, for example, in the manufacturing process of the distance-measuring device 1. Further, other than when the distance measuring device 1 is manufactured, a predetermined synchronization process for synchronizing the time information is executed in a state where the distance measuring device 1 and the distance measured side device 2 are connected by wire or wirelessly. , The time information in each device may be synchronized. A third communication device such as a roadside unit or an external server may intervene in the synchronization between the distance measuring device 1 and the distance measured side device 2. Further, when the distance measuring device 1 and the distance measured side device 2 are configured to be able to acquire the PPS signal (Pulse-Per-Second Signal) emitted by the GPS receiver, synchronization is performed with reference to the PPS signal. May be.

According to such a third embodiment, the distance measuring device 1 does not have to include the distance measuring side transmission unit 11 and the transmission control unit 131. Further, the distance-measured side device 2 does not have to include the distance-measured side receiving unit 21. Further, according to the third embodiment, it is not necessary to consider the response processing time τ in the distance-measured side device 2, so that the measurement is based on the error between the design response processing time τ and the actual response processing time τ. The distance error can be suppressed. That is, the distance measurement accuracy can be improved. Of course, also in this third embodiment, the configurations described in the first and second embodiments and various modifications can be applied. In the third embodiment, the signal of the first frequency transmitted by the distance-measured side device 2 corresponds to the first frequency signal according to the claim, and the signal of the second frequency transmitted by the distance-measured side device 2 corresponds to the signal of the first frequency. Corresponds to the second frequency signal according to the claim.

[Fourth Embodiment]
In the first to third embodiments and various modifications described above, the distance-measured side device 2 as a target is configured to be capable of transmitting signals of the first frequency f1 and the second frequency f2. , Not limited to this.

As shown in FIG. 8, the object (that is, the target) targeted by the ranging device 1 does not have a function for communicating with the ranging device 1 and reflects the signal transmitted from the ranging device 1. Thereby, it may be an object (hereinafter, a reflecting object) 2A that returns the transmitted signal to the distance measuring device 1 as a reflected wave. That is, the distance measuring device 1 may estimate the distance from the phase difference between the signal reflected by the reflecting object 2A as the target and returned and the transmission signal.

In this case, the reflecting object 2A may be an object having a property of reflecting radio waves of the first frequency and the second frequency, such as a metal body such as a vehicle or a human body. It is preferable that the distance measuring side transmitting unit 11 and the distance measuring side receiving unit 12 in the fourth embodiment are configured to transmit and receive radio waves in a predetermined direction. This is because if the distance measuring side transmitting unit 11 is omnidirectional, it is unclear in which direction the distance to the existing object is detected. The signal of the first frequency transmitted by the ranging device 1 is reflected by the reflector 2A and returned to the ranging device 1, which corresponds to the first feedback signal according to claim. Further, the signal of the second frequency transmitted by the ranging device 1 is reflected by the reflector 2A and returned to the ranging device 1, which corresponds to the second feedback signal according to claim.

The directivity of the distance measuring side transmitting unit 11 and the distance measuring side receiving unit 12 may be configured to be mechanically or software-changeable. According to such a configuration, the distance to the radio wave reflecting object existing in each distance measuring direction can be measured by rotating the direction to be measured. Of course, also in this fourth embodiment, the configurations described in the first and second embodiments and the modifications 1 and 3 can be applied.

100 ranging system, 1 ranging device, 2 ranging device, 11 ranging side transmitting unit, 12 ranging side receiving unit, 13 ranging side control unit, 21 ranging side receiving unit, 22 measuring distance Side control unit, 23 Ranged side transmitter

Claims (10)

A distance measuring device (1) including a transmission unit (11) for transmitting a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency. When,
When the first frequency signal transmitted from the distance measuring device is received, the first response signal having at least a part of the same signal sequence as the first frequency signal is returned at the first frequency. When the second frequency signal transmitted from the distance measuring device is received, the second response signal having at least a part of the same signal sequence as the second frequency signal is returned at the second frequency. It is a distance measuring system including a distance measuring side device (2) as a target.
The distance measuring device is
A receiving unit (12) that receives the first response signal and the second response signal returned from the distance-measured side device, and the receiving unit (12).
While detecting the first phase difference which is the phase difference of the first response signal received by the receiving unit with respect to the first frequency signal as a transmission signal, the receiving unit with respect to the second frequency signal as a transmission signal. A phase difference detecting unit (132) for detecting a second phase difference, which is a phase difference of the received second response signal, and a phase difference detecting unit (132).
A distance estimation unit (133) that acquires an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference that is the difference between the first phase difference and the second phase difference detected by the phase difference detection unit. ) And, with
The first frequency and the second frequency are set to frequencies different from the integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, respectively.
The distance estimation unit compares the phase expected value, which is the expected value of the first phase difference according to the estimated distance, with the actual detection value, which is the first phase difference actually detected by the phase difference detection unit. By doing so, it is determined whether or not the estimated distance is correct .
A table storage unit that stores a distance correspondence table showing the correspondence between the distance to the target and the expected phase value when the distance to the target is less than half of the difference wavelength which is the wavelength of the difference frequency. Equipped with M1)
The distance estimation unit acquires the minimum distance, which is the distance when the distance to the target is less than half of the difference wavelength, as the estimated distance.
When the phase expected value associated with the minimum distance and the actual detected value match in the distance correspondence table stored in the table storage unit, the minimum distance as the estimated distance is A distance measuring system characterized in that it is determined that the distance to the target is correct and the estimated distance is adopted as the distance to the target . A distance measuring device (1) including a transmission unit (11) for transmitting a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency. When,
When the first frequency signal transmitted from the distance measuring device is received, the first response signal having at least a part of the same signal sequence as the first frequency signal is returned at the first frequency. When the second frequency signal transmitted from the distance measuring device is received, the second response signal having at least a part of the same signal sequence as the second frequency signal is returned at the second frequency. It is a distance measuring system including a distance measuring side device (2) as a target.
The distance measuring device is
A receiving unit (12) that receives the first response signal and the second response signal returned from the distance-measured side device, and the receiving unit (12).
While detecting the first phase difference which is the phase difference of the first response signal received by the receiving unit with respect to the first frequency signal as a transmission signal, the receiving unit with respect to the second frequency signal as a transmission signal. A phase difference detecting unit (132) for detecting a second phase difference, which is a phase difference of the received second response signal, and a phase difference detecting unit (132).
A distance estimation unit (133) that acquires an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference that is the difference between the first phase difference and the second phase difference detected by the phase difference detection unit. ) And, with
The first frequency and the second frequency are set to frequencies different from the integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, respectively.
The distance estimation unit acquires the minimum distance, which is the distance when the distance to the target is less than half of the difference wavelength, which is the wavelength of the difference frequency, as the estimated distance, and the first first distance according to the estimated distance. It is determined whether or not the estimated distance is correct by comparing the expected phase value, which is the expected value of the phase difference, with the actual detected value, which is the first phase difference actually detected by the phase difference detecting unit . And
A phase expected value calculation unit (134) for calculating the phase expected value according to the estimated distance based on the minimum distance as the estimated distance and the first frequency is provided.
In the distance estimation unit, when the phase expected value calculated by the phase expected value calculation unit and the actual detected value match, the minimum distance as the estimated distance is correct as the distance to the target. A distance measuring system characterized in that the estimated distance is adopted as the distance to the target . A first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency are transmitted, and the first frequency signal is reflected and returned by the target. A distance measuring device that estimates the distance to the target by receiving the first feedback signal, which is an incoming signal, and the second feedback signal, which is a signal that the second frequency signal is reflected by the target and returned. A ranging system provided with (1).
The distance measuring device is
A transmission unit (11) for transmitting the first frequency signal and the second frequency signal, and
A receiving unit (12) for receiving the first feedback signal and the second feedback signal,
The first phase difference, which is the phase difference between the first frequency signal as a transmission signal and the first feedback signal received by the reception unit, is detected, and the second frequency signal as a transmission signal and the reception unit receive the first frequency signal. A phase difference detecting unit (132) for detecting a second phase difference, which is a phase difference of the received second feedback signal, and a phase difference detecting unit (132).
A distance estimation unit (133) that acquires an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference that is the difference between the first phase difference and the second phase difference detected by the phase difference detection unit. ) And, with
The first frequency and the second frequency are set to frequencies different from the integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, respectively.
The distance estimation unit compares the phase expected value, which is the expected value of the first phase difference according to the estimated distance, with the actual detection value, which is the first phase difference actually detected by the phase difference detection unit. By doing so, it is determined whether or not the estimated distance is correct .
A table storage unit that stores a distance correspondence table showing the correspondence between the distance to the target and the expected phase value when the distance to the target is less than half of the difference wavelength which is the wavelength of the difference frequency. Equipped with M1)
The distance estimation unit acquires the minimum distance, which is the distance when the distance to the target is less than half of the difference wavelength, as the estimated distance.
When the phase expected value associated with the minimum distance and the actual detected value match in the distance correspondence table stored in the table storage unit, the minimum distance as the estimated distance is A distance measuring system characterized in that it is determined that the distance to the target is correct and the estimated distance is adopted as the distance to the target . A first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency are transmitted, and the first frequency signal is reflected and returned by the target. A distance measuring device that estimates the distance to the target by receiving the first feedback signal, which is an incoming signal, and the second feedback signal, which is a signal that the second frequency signal is reflected by the target and returned. A ranging system provided with (1).
The distance measuring device is
A transmission unit (11) for transmitting the first frequency signal and the second frequency signal, and
A receiving unit (12) for receiving the first feedback signal and the second feedback signal,
The first phase difference, which is the phase difference between the first frequency signal as a transmission signal and the first feedback signal received by the reception unit, is detected, and the second frequency signal as a transmission signal and the reception unit receive the first frequency signal. A phase difference detecting unit (132) for detecting a second phase difference, which is a phase difference of the received second feedback signal, and a phase difference detecting unit (132).
A distance estimation unit (133) that acquires an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference that is the difference between the first phase difference and the second phase difference detected by the phase difference detection unit. ) And, with
The first frequency and the second frequency are set to frequencies different from the integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, respectively.
The distance estimation unit acquires the minimum distance, which is the distance when the distance to the target is less than half of the difference wavelength, which is the wavelength of the difference frequency, as the estimated distance, and the first first distance according to the estimated distance. It is determined whether or not the estimated distance is correct by comparing the expected phase value, which is the expected value of the phase difference, with the actual detected value, which is the first phase difference actually detected by the phase difference detecting unit . And
A phase expected value calculation unit (134) for calculating the phase expected value according to the estimated distance based on the minimum distance as the estimated distance and the first frequency is provided.
In the distance estimation unit, when the phase expected value calculated by the phase expected value calculation unit and the actual detected value match, the minimum distance as the estimated distance is correct as the distance to the target. A distance measuring system characterized in that the estimated distance is adopted as the distance to the target . A distance-measured side device (2) as a target for sequentially transmitting a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency.
Distance measurement including a distance measuring device (1) that estimates the distance between the distance measured side device and the distance measured side device by receiving the first frequency signal and the second frequency signal transmitted from the distance measured side device. It ’s a system,
A synchronization time information holding unit (135) that holds time information synchronized with the distance-measured side device, and
A receiving unit (12) for receiving the first frequency signal and the second frequency signal transmitted from the target, and
Based on the time information held by the synchronization time information holding unit, it occurs from the transmission of the first frequency signal by the distance-measured side device to the reception of the first frequency signal by the receiving unit. The first phase difference, which is the phase difference, is acquired, and the phase difference generated from the transmission of the second frequency signal by the distance-measured side device to the reception of the second frequency signal by the receiving unit. The phase difference detection unit (132) for detecting the second phase difference, which is
A distance estimation unit (133) that calculates an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference that is the difference between the first phase difference and the second phase difference detected by the phase difference detection unit. ) And, with
The first frequency and the second frequency are set to frequencies different from the integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, respectively.
The distance estimation unit compares the phase expected value, which is the expected value of the first phase difference according to the estimated distance, with the actual detection value, which is the first phase difference actually detected by the phase difference detection unit. By doing so, it is determined whether or not the estimated distance is correct .
A table storage unit that stores a distance correspondence table showing the correspondence between the distance to the target and the expected phase value when the distance to the target is less than half of the difference wavelength which is the wavelength of the difference frequency. Equipped with M1)
The distance estimation unit acquires the minimum distance, which is the distance when the distance to the target is less than half of the difference wavelength, as the estimated distance.
When the phase expected value associated with the minimum distance and the actual detected value match in the distance correspondence table stored in the table storage unit, the minimum distance as the estimated distance is A distance measuring system characterized in that it is determined that the distance to the target is correct and the estimated distance is adopted as the distance to the target . A distance-measured side device (2) as a target for sequentially transmitting a first frequency signal which is a predetermined first frequency signal and a second frequency signal which is a second frequency signal different from the first frequency.
Distance measurement including a distance measuring device (1) that estimates the distance between the distance measured side device and the distance measured side device by receiving the first frequency signal and the second frequency signal transmitted from the distance measured side device. It ’s a system,
A synchronization time information holding unit (135) that holds time information synchronized with the distance-measured side device, and
A receiving unit (12) for receiving the first frequency signal and the second frequency signal transmitted from the target, and
Based on the time information held by the synchronization time information holding unit, it occurs from the transmission of the first frequency signal by the distance-measured side device to the reception of the first frequency signal by the receiving unit. The first phase difference, which is the phase difference, is acquired, and the phase difference generated from the transmission of the second frequency signal by the distance-measured side device to the reception of the second frequency signal by the receiving unit. The phase difference detection unit (132) for detecting the second phase difference, which is
A distance estimation unit (133) that calculates an estimated value of the distance to the target as an estimated distance based on the two-frequency phase difference that is the difference between the first phase difference and the second phase difference detected by the phase difference detection unit. ) And, with
The first frequency and the second frequency are set to frequencies different from the integral multiple of the difference frequency, which is the difference between the first frequency and the second frequency, respectively.
The distance estimation unit acquires the minimum distance, which is the distance when the distance to the target is less than half of the difference wavelength, which is the wavelength of the difference frequency, as the estimated distance, and the first first distance according to the estimated distance. It is determined whether or not the estimated distance is correct by comparing the expected phase value, which is the expected value of the phase difference, with the actual detected value, which is the first phase difference actually detected by the phase difference detecting unit . And
A phase expected value calculation unit (134) for calculating the phase expected value according to the estimated distance based on the minimum distance as the estimated distance and the first frequency is provided.
In the distance estimation unit, when the phase expected value calculated by the phase expected value calculation unit and the actual detected value match, the minimum distance as the estimated distance is correct as the distance to the target. A distance measuring system characterized in that the estimated distance is adopted as the distance to the target . The ranging system according to claim 1.
The target is configured to be intercommunication with the ranging device using the first frequency and the second frequency.
When the target receives the first frequency signal and the second frequency signal, the target returns a signal containing predetermined data as the first response signal and the second response signal.
The first frequency signal, the second frequency signal, the first response signal, and the second response signal all have a preamble section having a predetermined signal waveform at the head of the signal sequence.
The phase difference detection unit is a distance measuring system characterized in that the first phase difference and the second phase difference are detected using the preamble section. The distance measuring system according to any one of claims 1, 3, 5 and 7 .
The distance correspondence table stored in the table storage unit has the correspondence relationship between the distance to the target and the phase expected value when the distance to the target is less than half of the difference wavelength. The data also shows the correspondence between the distance to the target and the expected phase value when the distance to the target is half or more of the difference wavelength.
The distance estimation unit is
When the phase expected value associated with the minimum distance and the actual detected value do not match in the distance correspondence table, the length obtained by multiplying half the length of the difference wavelength by an integral multiple is the minimum distance. At least one distance added to the target is acquired as a distance candidate with the target.
Of the at least one distance candidate, the distance candidate associated with the phase expected value that matches the actual detection value in the distance correspondence table is adopted as the distance to the target. system. The distance measuring system according to any one of claims 1, 3, 5 and 7 .
When the phase expected value associated with the minimum distance and the actual detected value do not match in the distance correspondence table, the distance estimation unit multiplied the length of half of the difference wavelength by an integral multiple. At least one distance obtained by adding the length to the minimum distance is calculated as a distance candidate with the target.
For each of the distance candidates calculated by the distance estimation unit, a phase expected value calculation unit (134) for calculating the phase expected value according to the distance candidate based on the first frequency is provided.
Of the at least one distance candidate, the distance estimation unit uses the distance candidate whose phase expected value calculated by the phase expected value calculation unit matches the actual detected value as the distance to the target. A distance measuring system characterized by being adopted. The distance measuring system according to any one of claims 2, 4, and 6 .
When the phase expected value and the actual detected value do not match the minimum distance calculated by the phase expected value calculation unit, the distance estimation unit has a length obtained by multiplying the length of half of the difference wavelength by an integral multiple. At least one distance obtained by adding the above to the minimum distance is calculated as a distance candidate with the target.
The phase expected value calculation unit calculates the phase expected value for each of the distance candidates calculated by the distance estimation unit.
Of the at least one distance candidate, the distance estimation unit uses the distance candidate whose phase expected value calculated by the phase expected value calculation unit matches the actual detected value as the distance to the target. A distance measuring system characterized by being adopted.

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