JP7029147B2 - Radio wave propagation distance estimation system - Google Patents

Description

The present invention relates to a radio wave propagation distance estimation device that estimates the propagation distance of radio waves reciprocating between a device and a portable device.

In the so-called smart key system (registered trademark), a technique for measuring the propagation time of radio waves reciprocating between an on-board unit and a portable device has been proposed as a countermeasure against fraudulent acts (relay attacks) using a repeater. (See, for example, Patent Documents 1 and 2).

By multiplying the propagation time by the speed of light, it is possible to estimate the distance from the device to the portable device while calculating the propagation distance. Then, when the estimated distance value exceeds the threshold value, it is determined that the relay attack is performed, and the door locking / unlocking and engine starting are not permitted.

Japanese Unexamined Patent Publication No. 2014-159685 Japanese Unexamined Patent Publication No. 2014-17603

The accuracy of distance estimation may be significantly deteriorated by disturbing the phase of radio waves due to multipath (diffuse reflection by the vehicle, re-radiation of current generated in the body, etc.). In this case, even though the portable device is near the vehicle, the estimated distance may exceed the threshold value, making it impossible to lock / unlock the door or start the engine. In addition, even though the portable device is far away, the estimated distance is below the threshold value, and there is a possibility that the door can be locked / unlocked or the engine can be started when the portable device is not near the vehicle.

The present invention has been made by paying attention to such a problem, and an object of the present invention is to provide a radio wave propagation distance estimation device capable of improving the distance estimation accuracy.

The radio wave propagation distance estimation device that solves the above problems is a radio wave propagation distance estimation device that estimates the propagation distance of the radio wave that reciprocates between the device and the portable device, and is a plurality of radio wave propagation distance estimation devices transmitted from a plurality of antennas mounted on the device. The portable device receives the first distance estimation signal including the frequency component of the above, and the second plurality of distance estimation signals are mounted on the device based on the first distance estimation signal received by the portable device. By replying to the antenna of the device, the device receives the second distance estimation signal, and the device is generated between the transmitted first distance estimation signal and the received second distance estimation signal. For the phase rotation amount at each frequency, the propagation distance is estimated by calculating the difference in the phase rotation amount between different frequencies, and the median value of the estimated plurality of the propagation distances is selected as the distance measurement value. It is the gist.

According to this configuration, the gradient in the relationship between frequency and phase rotation indicates the delay time of radio waves, so the distance from the device to the portable device is calculated while calculating the propagation distance by multiplying the delay time by the known speed of light. It is possible to estimate. In estimating the distance based on such a principle, it becomes easy to adopt a distance measurement value that is less affected by phase fluctuation due to multipath, and the distance estimation accuracy is improved. Therefore, the distance estimation accuracy can be improved.

Regarding the radio wave propagation distance estimation device, the device estimates the propagation distance for each of the plurality of antennas, sorts all the estimated propagation distances in order of the magnitude of the distance, and rearranges the estimated propagation distances. The propagation distance located at the center may be selected as the distance measurement value.

According to this configuration, the extreme value such as the maximum value and the minimum value, which are considered to be greatly affected by the phase fluctuation due to multipath, or a value close to the extreme value is not selected as the distance measurement value, but the center value is selected as the distance measurement value. In this way, the distance estimation accuracy can be improved by selecting a value that is considered to have the minimum or near the influence of the phase fluctuation due to multipath as the distance measurement value.

Regarding the radio wave propagation distance estimation device, the device estimates the propagation distance for each of the plurality of antennas, and rearranges the estimated propagation distance for each antenna in order of the magnitude of the distance. The propagation distance obtained by synthesizing the propagation distances for each antenna located at the center by rearrangement may be selected as the distance measurement value.

According to this configuration, extreme values such as maximum and minimum values, which are considered to be greatly affected by phase fluctuation due to multipath, are excluded from the target of synthesis processing, and the center value is set as the target of synthesis processing. do. In this way, values that are considered to have the least or near the effect of phase fluctuation due to multipath for each antenna are targeted for synthesis processing, and the values obtained by combining them are selected as distance measurement values. The estimation accuracy can be improved.

Regarding the radio wave propagation distance estimation device, the device estimates the propagation distance for each of the plurality of antennas, synthesizes the estimated propagation distance for each antenna, and obtains the combined processing. The propagation distance for each antenna may be rearranged in order of the magnitude of the distance, and the propagation distance located at the center may be selected as the distance measurement value by the rearrangement.

According to this configuration, after performing synthesis processing for each antenna to obtain the propagation distance for each antenna, the extreme values such as the maximum value and the minimum value, which are considered to be greatly affected by the phase fluctuation due to multipath, or Do not select a value close to it as the distance measurement value, but select the center value as the distance measurement value. In this way, the distance estimation accuracy can be improved by selecting a value that is considered to have the minimum or near the influence of the phase fluctuation due to multipath as the distance measurement value.

Regarding the radio wave propagation distance estimation device, the device uses the amplitude of the data at one of the two frequencies defining the different frequencies as the first amplitude and the amplitude of the data at the other frequency as the second amplitude. The value is large according to the value obtained by multiplying the first amplitude and the second amplitude with respect to the propagation distance estimated by calculating the difference in the amount of phase rotation between the different frequencies. It may be used for the synthesis process with the propagation distance estimated by calculating the difference in the amount of phase rotation between other different frequencies while weighting with a larger coefficient.

According to this configuration, the distance estimation accuracy can be improved by selecting the propagation distance obtained by performing the synthesis process with elaborate weighting as the distance measurement value.
Regarding the radio wave propagation distance estimation device, the device uses only the data whose amplitude is equal to or larger than the threshold value among the second distance estimation signals including the plurality of frequency components received by the plurality of antennas, and is different from the above. The propagation distance may be estimated by calculating the difference in the amount of phase rotation between frequencies.

According to this configuration, since the phase fluctuation tends to be large in the part where the amplitude is small, the data whose amplitude is less than the threshold value is not used for the distance estimation calculation, and only the data whose amplitude is equal to or more than the threshold value is used for propagation. Higher accuracy can be achieved by estimating the distance.

According to the present invention, the distance estimation accuracy can be improved.

Conceptual diagram of radio wave propagation distance estimation device. A characteristic diagram showing the relationship between frequency and phase rotation amount in free space. Phase characteristics affected by multipath. A method for selecting a distance measurement value according to the first embodiment. A method of selecting a distance measurement value according to the second embodiment. A method for selecting a distance measurement value according to a third embodiment.

(First Embodiment)
Hereinafter, the first embodiment of the radio wave propagation distance estimation device will be described.
As shown in FIG. 1, the radio wave propagation distance estimation device 1 wirelessly transmits a distance measuring signal obtained by synthesizing N sine waves having different frequencies from the on-board unit 2 to the portable device 3, and the portable device 3 keeps this as it is. It is sent back, and the vehicle-mounted device 2 receives the ranging signal. The distance measuring signal from the vehicle-mounted device 2 to the portable device 3 corresponds to the first distance estimation signal, and the distance measuring signal from the portable device 3 to the vehicle-mounted device 2 corresponds to the second distance estimation signal. The vehicle corresponds to the equipment.

As shown in FIG. 2, the phase rotation amount generated between the distance measuring signal currently transmitted by the vehicle-mounted device 2 and the distance measuring signal received by the vehicle-mounted device 2 is obtained for each frequency, and the adjacent frequencies are further obtained. The difference in the amount of phase rotation in. Since the inclination in the relationship between the frequency and the amount of phase rotation indicates the delay time of the ranging signal, the distance from the on-board unit 2 to the portable device 3 is calculated while calculating the propagation distance by multiplying the delay time by the known light speed c. It is possible to estimate. Then, when the estimated distance value is less than the threshold value, the door lock / unlock and engine start are permitted, and when the distance estimated value exceeds the threshold value, it is determined as a relay attack, and the door lock / unlock and engine start are not permitted. ..

Assuming that the distance measuring signal at time t transmitted from the vehicle-mounted device 2 is x (t), the distance measuring signal x (t) is expressed as follows.

Similarly, assuming that the distance measuring signal received by the vehicle-mounted device 2 is x'(t), x'(t) is expressed as follows.

To obtain the phase rotation amount θn at the nth frequency fn from the distance measuring signal received by the vehicle-mounted device 2, it is obtained by the following equation. From the difference in the amount of phase rotation at adjacent frequencies, the distance d is obtained by the following equation.

As described above, it is possible to estimate the distance by transmitting and receiving a distance measurement signal that combines N sine waves having different frequencies. However, the above is the case of propagation in free space. In free space, the amount of phase rotation increases in proportion to the propagation distance and frequency (see FIG. 2).
However, as shown in FIG. 3, when transmitting and receiving using an antenna attached to the vehicle, the phase rotation amount is no longer proportional to the propagation distance and frequency due to the influence of unnecessary current flowing through the vehicle body, and the distance is estimated. There will be an error in the result.

Therefore, the distance measurement signal is reciprocated between the plurality of antennas (corresponding to the on-board unit 2) and the portable device 3. The vehicle has different frequencies for the amount of phase rotation at each frequency generated between the distance measurement signals x (t) transmitted from the plurality of antennas and the distance measurement signals x'(t) received by the plurality of antennas. The distance d is calculated by calculating the difference in the amount of phase rotation of the above, and the median value of the calculated plurality of distances d is selected as the distance measurement value. This makes it possible to obtain high distance estimation accuracy.

Next, the operation of the radio wave propagation distance estimation device 1 will be described.
As shown in FIG. 4, three antennas (for convenience, antennas A to C) are mounted on the vehicle as a plurality of antennas, and four sine waves (frequency f1 to f4 for convenience) as N sine waves having different frequencies. ) Is used as a composite ranging signal.

For the antenna A, the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f1 and the frequency f2 is assumed to be "distance 1A" for convenience. Further, it is assumed that the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f2 and the frequency f3 for the antenna A is "distance 2A" for convenience. Further, it is assumed that the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f3 and the frequency f4 for the antenna A is "distance 3A" for convenience.

On the other hand, it is assumed that the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f1 and the frequency f2 for the antenna B is "distance 1B" for convenience. Further, it is assumed that the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f2 and the frequency f3 for the antenna B is "distance 2B" for convenience. Further, it is assumed that the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f3 and the frequency f4 for the antenna B is "distance 3B" for convenience.

On the other hand, it is assumed that the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f1 and the frequency f2 for the antenna C is "distance 1C" for convenience. Further, it is assumed that the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f2 and the frequency f3 for the antenna C is "distance 2C" for convenience. Further, it is assumed that the propagation distance estimated by calculating the difference in the amount of phase rotation between the frequency f3 and the frequency f4 for the antenna C is "distance 3C" for convenience.

Then, when all the propagation distances estimated as described above are rearranged in order of the magnitude of the distance, in this example, "3B> 1A> 2A> 2C> 3A> 3C> 1C> 1B> 2B in order from the largest one. ". In this case, the distance 3A located at the center is selected as the distance measurement value by the above rearrangement, and 1/2 of the distance 3A is estimated as the distance from the vehicle-mounted device 2 to the portable device 3.

As described above, according to the present embodiment, the following effects can be obtained.
(1) By selecting the median value of the calculated multiple distances d (distance 3A in this example) as the distance measurement value, it becomes easier to adopt the distance measurement value that is less affected by the phase fluctuation due to multipath, and the distance estimation accuracy. Is improved. Therefore, the distance estimation accuracy can be improved.

(2) Do not select extreme values such as maximum and minimum values, which are considered to be greatly affected by phase fluctuation due to multipath, or values close to them as distance measurement values, and use the median value (distance 3A in this example) as the distance measurement value. Select as. In this way, the distance estimation accuracy can be improved by selecting a value that is considered to have the minimum or near the influence of the phase fluctuation due to multipath as the distance measurement value.

(Second embodiment)
Next, a second embodiment of the radio wave propagation distance estimation device will be described.
As shown in FIG. 5, based on the same assumption as in the first embodiment, in this example, the estimated propagation distances are rearranged in order of distance in units of antennas. That is, "1A>2A>3A" for antenna A in order from the largest one, "3B>1B>2B" for antenna B in order from the largest one, and "3B>1B>2B" for antenna C in order from the largest one. "2C>3C>1C".

Then, the distances 2A, 1B, and 3C for each antenna located at the center are combined by the above rearrangement. In this example, the following maximum ratio synthesis process is performed as the synthesis process. That is, of the frequencies f2 and f3 used for calculating the distance 2A, the amplitude of one frequency f2 is "2 mV" for convenience, and the amplitude of the other frequency f3 is "3 mV" for convenience. Further, of the frequencies f1 and f2 used for calculating the distance 1B, the amplitude of one of the frequencies f1 is "2 mV" for convenience, and the amplitude of the other frequency f2 is "1 mV" for convenience. Further, of the frequencies f3 and f4 used for calculating the distance 3C, the amplitude of one frequency f3 is "1 mV" for convenience, and the amplitude of the other frequency f4 is "2 mV" for convenience.

Then, in the processing of the maximum ratio synthesis in this case, the propagation distance of each antenna located in the center is multiplied by the amplitudes of the two frequencies used for calculating the propagation distance by the above rearrangement. Therefore, the larger the value, the larger the coefficient, and the weighting is performed, and the weight is added to the propagation distance of each other antenna. In this example, the distance 2A of the antenna A is weighted with a coefficient "0.6" in proportion to the magnitude of the value obtained by multiplying the two amplitudes, and the distance 1B of the antenna B and the distance 3C of the antenna C are used. After weighting each with a coefficient of "0.2", the propagation distance and the coefficient are multiplied for each antenna, and these are added to obtain the maximum ratio composite value of the propagation distance. The maximum ratio composite value in this case is represented by "distance 2A x 0.6 + distance 1B x 0.2 + distance 3C x 0.2".

Then, the maximum ratio composite value is selected as the distance measurement value, and 1/2 of the maximum ratio composite value is estimated as the distance from the vehicle-mounted device 2 to the portable device 3.
As described above, according to the present embodiment, the following effects can be obtained.

(3) Extreme values such as maximum and minimum values, which are considered to be greatly affected by phase fluctuation due to multipath for each antenna, or values close to them are excluded from the target of synthesis processing, and the center value (distance 2A, 1B in this example, 3C) is the target of the synthesis process. In this way, the values that are considered to have the least or near the effect of phase fluctuation due to multipath for each antenna are targeted for synthesis processing, and the values obtained by combining them (maximum ratio composite value in this example) are measured. By selecting it as the distance value, the distance estimation accuracy can be improved.

(4) The distance estimation accuracy can be improved by selecting the propagation distance (maximum ratio composite value in this example) obtained by performing the synthesis process with elaborate weighting as the distance measurement value.
(Third embodiment)
Next, a third embodiment of the radio wave propagation distance estimation device will be described.

As shown in FIG. 6, based on the same assumption as in the first embodiment, in this example, the estimated propagation distance is combined for each antenna, and the propagation distance for each antenna obtained by the combined processing is calculated. Sort by the magnitude of the distance, and select the propagation distance located in the center as the distance measurement value by the sorting.

In this example, the maximum ratio synthesis process is performed as the synthesis process for each antenna. For the sake of convenience, the explanation using specific numerical values is omitted, but in the processing of maximum ratio synthesis, the two frequencies used for calculating the propagation distance for each antenna (frequency f1 and frequency f2 in the example of the antenna A distance 1A). In the example of the distance 3C of the antenna C, weighting is performed according to the value obtained by multiplying the respective amplitudes of the frequency f3 and the frequency f4) by the same principle as in the second embodiment. Then, for each antenna, the weighting coefficient is multiplied by the corresponding propagation distance, and they are added. As a result, the maximum ratio composite value of the propagation distance can be obtained for each antenna.

Then, the maximum ratio composite value for each antenna is sorted in order of the magnitude of the distance, and the maximum ratio composite value located in the center (for example, the maximum ratio composite value of antenna A) is selected as the distance measurement value by the sort, and this maximum is selected. 1/2 of the specific composite value is estimated as the distance from the on-board unit 2 to the portable device 3.

As described above, according to the present embodiment, the following effects can be obtained.
(5) After performing synthesis processing for each antenna to obtain the propagation distance for each antenna (maximum ratio composite value in this example), the maximum value and the maximum value that are considered to be greatly affected by the phase fluctuation due to multipath. The extreme value such as the minimum value or a value close to it is not selected as the distance measurement value, but the center value (in this example, the maximum ratio composite value of the antenna A) is selected as the distance measurement value. In this way, the distance estimation accuracy can be improved by selecting a value that is considered to have the minimum or near the influence of the phase fluctuation due to multipath as the distance measurement value.

(6) The distance estimation accuracy can be improved by selecting the propagation distance (in this example, the maximum ratio composite value of the antenna A) obtained by undergoing the synthesis process with elaborate weighting as the distance measurement value.

It should be noted that each of the above embodiments can be modified and embodied as follows.
-As the synthesis process, instead of the maximum ratio synthesis process, a so-called equal gain synthesis process in which the propagation distance is added without weighting may be adopted. Further, weighting may be performed by a method different from the maximum ratio composition.

-Synthesis processing such as maximum ratio synthesis may be performed before conversion to the propagation distance, not after conversion to the propagation distance.
-Instead of estimating the propagation distance by using all the data regardless of the magnitude of the amplitude and calculating the difference in the amount of phase rotation between different frequencies, only the data whose amplitude is greater than or equal to the threshold is used and different. The propagation distance may be estimated by calculating the difference in the amount of phase rotation between frequencies. According to this configuration, since the phase fluctuation tends to be large in the part where the amplitude is small, the data whose amplitude is less than the threshold value is not used for the distance estimation calculation, and only the data whose amplitude is equal to or more than the threshold value is used for propagation. Higher accuracy can be achieved by estimating the distance.

-A plurality of distance measurement values may be selected as the corresponding distance measurement values, and the average value thereof may be selected as the distance measurement value.
A signal after electrical processing such as modulation processing of the original signal is transmitted from a plurality of antennas as a ranging signal x (t). For this reason, a phase rotation amount is generated between the ranging signal x (t) transmitted from the plurality of antennas and the original signal due to the modulation processing in the vehicle, and the phase in the vehicle is generated. The rotation amount may be calculated in advance, and the ranging signal x (t) based on the corrected phase rotation amount excluding the rotation amount may be transmitted from the plurality of antennas. In this way, the distance estimation accuracy is achieved by transmitting the ranging signal x (t) based on the corrected phase rotation amount excluding the phase rotation amount at each frequency generated between the original signal and the original signal from the plurality of antennas. Can be improved.

-A vehicle is equipped with two or four or more antennas as a plurality of antennas, and distance estimation is performed by the same principle as in each of the above-described embodiments while reciprocating a distance measurement signal between each antenna and the portable device 3. You may go.

-Instead of estimating the propagation distance by calculating the difference in the amount of phase rotation between adjacent frequencies in the frequency band including frequencies f1 to f4, the amount of phase rotation between different frequencies not adjacent in the frequency band The propagation distance may be estimated by calculating the difference.

・ Equipment is not limited to vehicles. The present invention may be applied to a radio wave propagation distance estimation device in which a plurality of antennas are mounted on a door of a building or the like and the propagation distance of radio waves reciprocating to and from a portable device is estimated. Then, when the estimated distance value exceeds the threshold value, it may be determined as a relay attack, and the door locking / unlocking or the operation of the electric appliance may be disallowed. It can be applied to electronic key systems for vehicles or buildings.

Next, the technical ideas that can be grasped from each of the above embodiments and other examples will be described.
(B) In the radio wave propagation distance estimation device, the device obtains the first distance estimation signal based on the corrected phase rotation amount excluding the phase rotation amount at each frequency generated between the original signal and the original signal. Transmit from multiple antennas.

According to this configuration, a phase rotation amount is generated between the first distance estimation signal transmitted from a plurality of antennas and the original signal due to the modulation processing in the device, but in such a device. The distance estimation accuracy can be improved by calculating the phase rotation amount in advance and using the corrected phase rotation amount excluding it as a reference.

1 ... Radio wave propagation distance estimation device, 2 ... On-board unit (multiple antennas), 3 ... Portable device, AC ... Antenna.

Claims (8)

Radio wave propagation distance estimation that has a first device equipped with a plurality of antennas and a second device equipped with antennas , and estimates the propagation distance of radio waves reciprocating between the first device and the second device. In the system
A plurality of antennas of the first device transmit a first distance estimation signal which is a composite wave of a signal having a plurality of frequency components.
Based on the reception of the first distance estimation signal, the antenna of the second device transmits the second distance estimation signal, which is a composite wave of the signals having the plurality of frequency components.
The first device sets the phase rotation amount of the second distance estimation signal with respect to the first distance estimation signal as each frequency component for each of the second distance estimation signals received by each antenna of the first device. Calculated and
The propagation distance is estimated based on the difference in the amount of phase rotation for each of a plurality of combinations of different frequency components.
The first device estimates the propagation distance for each of the plurality of antennas, rearranges all the estimated propagation distances in order of the magnitude of the distance, and is located in the center by the rearrangement. A radio wave propagation distance estimation system characterized in that a distance value is acquired by selecting a propagation distance. In a radio wave propagation distance estimation system that has a first device equipped with a plurality of antennas and a second device equipped with antennas, and estimates the propagation distance of radio waves reciprocating between the first device and the second device.
A plurality of antennas of the first device transmit a first distance estimation signal which is a composite wave of a signal having a plurality of frequency components.
Based on the reception of the first distance estimation signal, the antenna of the second device transmits the second distance estimation signal, which is a composite wave of the signals having the plurality of frequency components.
The first device sets the phase rotation amount of the second distance estimation signal with respect to the first distance estimation signal as each frequency component for each of the second distance estimation signals received by each antenna of the first device. Calculated and
The propagation distance is estimated based on the difference in the amount of phase rotation for each of a plurality of combinations of different frequency components.
The first device estimates the propagation distance for each of the plurality of antennas, rearranges the estimated propagation distance in units of antennas in order of distance magnitude, and positions the estimated propagation distance in the center by the rearrangement. A radio wave propagation distance estimation system characterized in that the propagation distance obtained by synthesizing the propagation distances for each antenna is acquired as a distance measurement value. In a radio wave propagation distance estimation system that has a first device equipped with a plurality of antennas and a second device equipped with antennas, and estimates the propagation distance of radio waves reciprocating between the first device and the second device.
A plurality of antennas of the first device transmit a first distance estimation signal which is a composite wave of a signal having a plurality of frequency components.
Based on the reception of the first distance estimation signal, the antenna of the second device transmits the second distance estimation signal, which is a composite wave of the signals having the plurality of frequency components.
The first device sets the phase rotation amount of the second distance estimation signal with respect to the first distance estimation signal as each frequency component for each of the second distance estimation signals received by each antenna of the first device. Calculated and
The propagation distance is estimated based on the difference in the amount of phase rotation for each of a plurality of combinations of different frequency components.
The first device estimates the propagation distance for each of the plurality of antennas, synthesizes the estimated propagation distance for each antenna, and performs the propagation for each antenna obtained by the synthesis processing. A radio wave propagation distance estimation system characterized in that distances are rearranged in order of magnitude of distance, and the propagation distance located in the center is acquired as a distance measurement value by the rearrangement. The first device has the amplitude of the second distance measurement signal at one of the two frequencies defining the different frequencies as the first amplitude, and the second distance measurement signal at the other frequency. The amplitude is set as the second amplitude, and the propagation distance estimated by calculating the difference in the amount of phase rotation between the different frequencies is set to the value obtained by multiplying the first amplitude and the second amplitude. Therefore, the larger the value, the larger the weighting by the coefficient, and it is used for the synthesis process with the propagation distance estimated by calculating the difference in the amount of phase rotation between other different frequencies.
The radio wave propagation distance estimation system according to claim 2 or 3 . The first device uses only the frequency whose amplitude is equal to or higher than the threshold value among the second distance estimation signals including the plurality of frequency components received by the plurality of antennas, and the amount of phase rotation between the different frequencies. Estimate the propagation distance by calculating the difference between
The radio wave propagation distance estimation system according to any one of claims 1 to 4 . Radio wave propagation distance estimation that has a first device equipped with a plurality of antennas and a second device equipped with antennas , and estimates the propagation distance of radio waves reciprocating between the first device and the second device. In the system
The plurality of antennas of the first device transmit the first ranging signal component , which is a frequency component at each of the plurality of frequencies,.
Based on the reception of the first ranging signal component, the antenna of the second device transmits the second ranging signal component which is a frequency component at each of the plurality of frequencies.
The first device determines the phase rotation amount of the second range-finding signal component with respect to the first range-finding signal component for each of the second range-finding signal components received by each antenna of the first device. Calculate for each frequency component,
The propagation distance is estimated based on the difference in the amount of phase rotation for each of a plurality of combinations of different frequency components.
The first device estimates the propagation distance for each of the plurality of antennas, rearranges all the estimated propagation distances in order of the magnitude of the distance, and is located in the center by the rearrangement. A radio wave propagation distance estimation system characterized in that a distance value is acquired by selecting a propagation distance. In a radio wave propagation distance estimation system that has a first device equipped with a plurality of antennas and a second device equipped with antennas, and estimates the propagation distance of radio waves reciprocating between the first device and the second device.
The plurality of antennas of the first device transmit the first ranging signal component, which is a frequency component at each of the plurality of frequencies,.
Based on the reception of the first ranging signal component, the antenna of the second device transmits the second ranging signal component which is a frequency component at each of the plurality of frequencies.
The first device determines the phase rotation amount of the second range-finding signal component with respect to the first range-finding signal component for each of the second range-finding signal components received by each antenna of the first device. Calculate for each frequency component,
The propagation distance is estimated based on the difference in the amount of phase rotation for each of a plurality of combinations of different frequency components.
The first device estimates the propagation distance for each of the plurality of antennas, rearranges the estimated propagation distance in units of antennas in order of distance magnitude, and positions the estimated propagation distance in the center by the rearrangement. A radio wave propagation distance estimation system characterized in that the propagation distance obtained by synthesizing the propagation distances for each antenna is acquired as a distance measurement value. In a radio wave propagation distance estimation system that has a first device equipped with a plurality of antennas and a second device equipped with antennas, and estimates the propagation distance of radio waves reciprocating between the first device and the second device.
The plurality of antennas of the first device transmit the first ranging signal component, which is a frequency component at each of the plurality of frequencies,.
Based on the reception of the first ranging signal component, the antenna of the second device transmits the second ranging signal component which is a frequency component at each of the plurality of frequencies.
The first device determines the phase rotation amount of the second range-finding signal component with respect to the first range-finding signal component for each of the second range-finding signal components received by each antenna of the first device. Calculate for each frequency component,
The propagation distance is estimated based on the difference in the amount of phase rotation for each of a plurality of combinations of different frequency components.
The first device estimates the propagation distance for each of the plurality of antennas, synthesizes the estimated propagation distance for each antenna, and performs the propagation for each antenna obtained by the synthesis processing. A radio wave propagation distance estimation system characterized in that distances are rearranged in order of magnitude of distance, and the propagation distance located in the center is acquired as a distance measurement value by the rearrangement.

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