JP2000009851A - Object detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily detect a plurality of objects to be detected, by constituting an apparatus simple. SOLUTION: Three antennas 32, 34, 36 are connected in an array shape to one trunk cable 10 via branch parts 12, 14, 16 whose distribution ratio can be set and via stay cables 22, 24, 26. A high-frequency pulse signal is output from a controller 40 which is connected to one end of the trunk cable 10. The branch parts 12, 14, 16 are constituted of directional couplers. Traveling waves 20F are distributed to the stay cables 22, 24, 26 in a preset distribution ratio. Nearly identical power is supplied to the antennas 32, 34, 36 irrespective of a cable length. Reflected waves 20B as their reflection are couled by the directional couplers so as to be fed back. In the controller 40, the existence of an object Obj to be detected is detected by the time difference of the reflected waves 20B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object detecting device, and more particularly to an object detecting device for detecting the presence or absence of an object using electromagnetic waves.

[0002]

2. Description of the Related Art Conventionally, there is an object detecting device which emits a high-frequency radio wave and detects a reflected wave thereof to detect an object without contact. The object detection device is suitable for detecting, for example, the presence or absence of a vehicle, and is capable of measuring traffic volume and grasping the availability of a parking lot (full / vacant).

Since the measurement of the emission of a high-frequency radio wave and the reflected wave thereof requires the detection of a weak radio wave, an antenna for measuring the emission of the radio wave and the reflected wave and a cable to the antenna are further attached to the object to be detected. Preferably. In general, transmission of a high-frequency signal (traveling wave) and reception of a reflected wave from an object to be detected are transmitted using a coaxial cable.

However, it is known that a coaxial cable has a transmission loss, and as its length becomes longer,
The detection sensitivity of the detected object decreases. For this reason, two coaxial cables of the same length are provided in parallel and alternately in direction, that is, a cable provided with a transmitter at one end and a cable provided with a receiver at one end are connected to a transmitter and a receiver. There is known a technique in which a transmission device is positioned near the other end of each other so that when detected, the lengths of high-frequency transmission passing through a cable are matched to suppress transmission loss (Japanese Patent Laid-Open Publication No. Hei. 13991).

[0005]

However, in the conventional object detecting device, it is effective to detect one detected object along the object detecting device. However, it is necessary to detect the object at a plurality of separated positions such as remote places. However, it is necessary to extend the cable group of one pair, the detection part becomes complicated, and complicated construction is required.

An object of the present invention is to provide an object detection device capable of easily detecting a plurality of detected objects in consideration of the above fact.

[0007]

When the present invention is applied to a vehicle as an object to be detected, the preferred examples of the vehicle detection include a parking lot situation (full / empty) and an AHS (automated highway system, automatic driving). System) vehicle position detection. In these detections, an output such as “where and how many vehicles are present” may be required for an arbitrary area, not only for a specific point. In such applications, application of the area detection technique in image detection is generally desired, but is impractical due to various problems and restrictions such as subtle detection condition settings.

Therefore, in reality, a required number of point detection sensors such as loop coils and ultrasonic sensors are arranged. Although these sensors themselves are inexpensive, a great deal of cost and labor is required to install a large number of them and to perform wiring for each sensor to the control device. The present inventors have obtained the finding that an object detection device having a high degree of freedom and high accuracy is possible by considering the loss of a high-frequency electric signal, and reached the present invention.

More specifically, the object detecting apparatus according to the first aspect of the present invention detects radiation of a radio wave corresponding to an input high-frequency pulse signal and reflection of the radiated radio wave and outputs the detected signal as a feedback signal. A plurality of antennas, one trunk cable, and a plurality of branch cables each having one end connected to each of the plurality of antennas and the other end connected to the trunk cable, and each of the branch cable are provided. A plurality of adjusting means for adjusting an input signal to a signal of a predetermined power, connected to the trunk cable, output means for outputting a high-frequency pulse signal to the trunk cable, and connected to the trunk cable Detecting means for detecting the feedback signal and detecting an object to be detected in the vicinity of each of the plurality of antennas based on the detected feedback signal. .

According to a second aspect of the present invention, in the object detecting device of the first aspect, the adjusting means converts the high-frequency pulse signal transmitted to the antenna into a high-frequency pulse signal of a predetermined power. It is characterized by adjusting.

According to a third aspect of the present invention, in the object detection device according to the first or second aspect, the adjusting means comprises an attenuator for attenuating the power of the input high-frequency pulse signal. I do.

According to a fourth aspect of the present invention, in the object detecting device according to the first aspect, the adjusting means adjusts a feedback signal from the antenna to a feedback signal having a predetermined power. I do.

According to a fifth aspect of the present invention, in the object detection device according to the second or third aspect, a feedback signal of a predetermined power, which is provided in each of the branch cables and has a predetermined feedback signal from the antenna. And a feedback signal adjusting means for adjusting the feedback signal.

According to a sixth aspect of the present invention, in the object detecting device according to the fifth aspect, the feedback signal adjusting means is arranged such that each of the branch cables separates the high-frequency pulse signal from the feedback signal. Are provided.

According to a seventh aspect of the present invention, in the object detection device according to the fifth or sixth aspect, the feedback signal adjusting means comprises an attenuator for attenuating the power of the feedback signal. .

According to an eighth aspect of the present invention, in the object detection device according to any one of the first to seventh aspects, the trunk cable is buried in a transverse direction of a traveling path of the vehicle.
Each of the plurality of antennas is installed so as to correspond to each lane.

According to a ninth aspect of the present invention, in the object detection device according to any one of the first to eighth aspects, the trunk cable is provided in a vehicle area including a plurality of exclusive areas specific to the vehicle. The antenna is buried, and each of the plurality of antennas is installed in each of the plurality of exclusive areas unique to the vehicle.

An object detection apparatus according to a tenth aspect of the present invention includes a plurality of antennas for detecting radiation of a radio wave corresponding to the input high-frequency pulse signal and reflection of the radiated radio wave and outputting the detected signal as a feedback signal; A trunk cable group including at least a traveling wave cable for transmitting a high-frequency pulse signal and a reflected wave cable for transmitting the feedback signal, and one end is connected to each of the plurality of antennas, and the other end is the trunk. A plurality of branch cables connected to each of the traveling wave cable and the reflected wave cable of the cable group, and a high frequency pulse signal provided to each of the branch cables and transmitted to the antenna having a predetermined power. A plurality of adjusting means for adjusting to a high-frequency pulse signal, connected to the trunk cable group; Output means for outputting a signal, and connected to the trunk cable group, and detects the return signal, and a detection means for detecting a detected object near each of the plurality of antennas based on the detected return signal, It has.

[0019] According to an eleventh aspect of the present invention, in the object detecting device according to the tenth aspect, each of the branch cables is provided with a circulator for separating the high-frequency pulse signal and the feedback signal. I do.

According to a twelfth aspect of the present invention, in the object detecting device of the eleventh aspect, each of the branch cables is provided with a distributor for distributing a high-frequency pulse signal transmitted through the traveling wave cable. A cable is connected to a traveling wave cable of the cable group and is connected to a reflected wave cable of the trunk cable group by a directional coupler.

According to the first aspect of the present invention, a branch cable is connected to each of the plurality of antennas. The other end of each of the branch cables is connected to a main cable through which a high-frequency pulse signal output from the output unit is transmitted. Therefore, the high-frequency pulse signal is transmitted as a traveling wave through one trunk cable, reaches the antenna via the branch cable, and is radiated as radio waves. This radiated radio wave is reflected when an object to be detected is present, and is returned to the antenna. Then, the return signal from the antenna is transmitted as a reflected wave through the same one trunk cable via the branch cable. The detecting means detects a feedback signal of a high-frequency pulse signal that is a reflected wave. At the same time, the detection means
An object to be detected near each of the plurality of antennas is detected based on the detected feedback signal. That is, the high-frequency pulse signal and the feedback signal transmitted as the traveling wave have a time delay (phase delay) due to being reflected when the detected object is present. Since this time delay (phase delay) corresponds to the installation position of the antenna, the presence of the detected object near the corresponding antenna can be detected. On the other hand, when the object to be detected does not exist, the reflected wave does not exist for the antenna, so that the antenna is not detected. In this manner, a detected object near each of the plurality of antennas can be detected.

Incidentally, transmission loss may occur in a high-frequency cable. Since the transmission loss increases according to the length of the high-frequency cable, the power of the radio wave radiated to the detected object decreases. Therefore, the power of at least one of the high-frequency pulse signal and the feedback signal decreases in accordance with the length of the high-frequency cable, and the object to be detected may not be detected. Therefore, in the present invention, the input signal is adjusted to a signal of a predetermined power by an adjusting means provided on the branch cable. As a result, the power of any one of the high-frequency pulse signal and the feedback signal input to the antenna becomes constant irrespective of the length of the trunk cable, which is a high-frequency cable, and the high-frequency pulse signal and the feedback signal are stably transmitted. Obtainable.

In the detection of an object to be detected, it is preferable to stably emit radio waves toward the object to be detected. Therefore, as described in claim 2, the adjusting means adjusts the high-frequency pulse signal transmitted to the antenna to a high-frequency pulse signal having a predetermined power. As a result, the power of the high-frequency pulse signal input to the antenna becomes constant irrespective of the length of the main cable, and radio waves are stably radiated to the detected object.

Further, the adjusting means may be constituted by an attenuator for attenuating the power of the input high-frequency pulse signal.

In the detection of the detected object, it is preferable to stably detect the radio wave reflected from the detected object. Therefore, as described in claim 4, the feedback signal from the antenna is adjusted to a feedback signal of a predetermined power by the adjusting means. As a result, the power of the feedback signal output from the antenna becomes constant irrespective of the length of the trunk cable, and the feedback signal can be obtained stably.

In the detection of an object to be detected, both stable emission of radio waves toward the object to be detected and stable detection of radio waves reflected from the object to be detected are preferable. Therefore,
According to a fifth aspect of the present invention, in the object detection device having the adjusting means, each of the branch cables further includes a feedback signal adjusting means for adjusting a feedback signal from the antenna to a feedback signal having a predetermined power. As a result, the power of both the high-frequency pulse signal and the feedback signal becomes constant regardless of the length of the backbone cable, and a stable signal can be obtained.

In order to further provide a feedback signal adjusting means to the object detecting device having the adjusting means, it is preferable to separate the high frequency pulse signal and the feedback signal from the branch cable. Therefore, as described in claim 6, the feedback signal adjusting means is configured to include a circulator for separating the high-frequency pulse signal and the feedback signal, and the circulator is provided in each of the branch cables, so that the high-frequency pulse signal and Both powers of the feedback signal can be stably obtained without being affected by the length of the trunk cable.

It is to be noted that the feedback signal adjusting means is provided in claim 7.
As described in the above, it can be configured with an attenuator for attenuating the power of the feedback signal.

As described above, when applied to a vehicle as an object to be detected, it is preferable to bury the object in the ground from the viewpoint of landscape and construction. Therefore, as described in claim 8, the trunk cable is buried in a direction transverse to the traveling path of the vehicle, and each of the plurality of antennas is installed corresponding to each lane. By doing so, the trunk cable can be buried in the shortest distance, and the running vehicle runs along the lane, so that the detected object near each of the antennas can be easily detected.

In a case where the present invention is applied to a vehicle as an object to be detected, in a facility such as a parking lot, there is a case where a lane is not provided even if there is a section (parking space) of an area where the vehicle can enter. Therefore, as described in claim 9, the trunk cable is buried in a vehicle area composed of a plurality of vehicle-specific exclusive areas corresponding to sections of the area where vehicles can enter. Then, each of the plurality of antennas is installed in each of the exclusive areas unique to the plurality of vehicles. As a result, the detected object can be easily detected even in a region where no lane is provided.

In the above description, the traveling wave and the reflected wave are both transmitted within one trunk cable, but the transmission of the traveling wave and the reflected wave may be separated. That is, as described in claim 10, a trunk cable group including at least a traveling wave cable for transmitting a high-frequency pulse signal and a reflected wave cable for transmitting a feedback signal can be used. The high-frequency pulse signal output from the output means is transmitted through a traveling-wave cable, reaches an antenna via a branch cable, and is radiated as radio waves. This radiated radio wave is reflected when an object to be detected is present, and is returned to the antenna. Then, the reflected wave cable is transmitted as a reflected wave via the antenna and the branch cable. The detecting means detects a feedback signal of a high-frequency pulse signal that is a reflected wave,
An object to be detected near each of the plurality of antennas is detected based on the detected feedback signal. That is, the detected objects near each of the plurality of antennas are detected from the time delay (phase delay) of the reflected wave when the detected object is present.

[0032] Each of the branch cables may include a circulator for separating the traveling wave and the reflected wave. by this,
It becomes easy to separate the traveling wave and the reflected wave.

Since the traveling wave is only required for radiation and the reflected wave needs to be detected in the same state, there is no need to combine them. Therefore, each of the branch cables is connected to a traveling wave cable of the trunk cable group by a distributor for distributing a high-frequency pulse signal transmitted through the traveling wave cable, as described in claim 12, and It can be connected to the reflected wave cable of the trunk cable group by a sex coupler. By doing so, it is possible to reliably transmit the signals separated by the traveling wave and the reflected wave according to the intended use.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment] In the first embodiment, the present invention is applied to a vehicle detection device for grasping the state of a parking lot (full / vacant).

First, a description will be given of a detection principle in the present embodiment in consideration of transmission loss occurring in a cable when detecting the presence or absence of an object by the emission and reflection of radio waves.

As shown in FIG. 1, a single trunk cable (high-frequency cable) 10 has a branching unit 1 capable of setting a distribution ratio for distributing signals transmitted through the trunk cable 10.
2, 14, and 16 are provided (details will be described later). Each of the branch portions 12 to 16 has a branch cable 22,
A plurality (three in the example of FIG. 1) connected via 4, 26
Antennas 32, 34 and 36 are provided. A controller 40 that controls the output of the high-frequency pulse signal is connected to one end of the trunk cable 10. A terminator 39 is connected to the other end of the trunk cable 10.

In the following description, a case where a transmission signal is branched into three from one trunk cable 10 will be described. However, the present invention is also applicable to a case where a transmission signal is branched into two or four or more transmission signals. is there.

Each of the antennas 32, 34, and 36 is preferably a planar patch antenna having a low ground height when installed in a parking lot. In addition, the branch 1 of the trunk cable 10
2, 14, and 16 need to appropriately branch or merge the transmitted high-frequency pulse signal on the forward path and the return path.
A directional coupler (FIG. 2) is used.

As shown in FIG. 2, the forward high-frequency pulse signal output from the controller 40 and transmitted is converted into a traveling wave 2
0F, and the return high-frequency pulse signal transmitted by the antenna receiving the reflection of the electromagnetic wave pulse radiated from the antenna 32 is referred to as a reflected wave 20B. The branching unit 12 is formed of a directional coupler, and the traveling wave 20F is distributed to the branch cable 22 at a preset distribution ratio (described later), and the reflected wave 20B, which is a reflection thereof, returns. The reflected wave 20B allows the signal to be coupled only by the directional coupler in the traveling direction of the reflected wave, that is, in the direction toward the controller 40. Therefore, a signal effective only for detection is returned to the controller 40 without the reflected wave 20B interfering with the traveling wave 20F.

The controller 40 generates and outputs a high-frequency pulse signal. The output high-frequency pulse signal is transmitted to the trunk cable 10 and the branch cables 22, 24, 2
6 and transmitted to each antenna 32, 34, 36,
The electromagnetic wave pulses 42, 4 from each of the antennas 32, 34, 36
4, 46 are emitted.

A substantially constant power Pt is supplied to the antennas 32 to 36 by setting the distribution ratio from the trunk cable 10 for each of the branching units 12 to 16. Branches 12-1 composed of these directional couplers
The distribution ratio of 6 is set in advance so that substantially constant power Pt is supplied to each antenna. The distribution ratio of the i-th (≧ 1) -th branch portion can be expressed by the following equation (1).

Distribution ratio of i-th branch (Pt + Lu): (ni) × (Pt + Ls + Lu) (1) P = n · (Pt + Ls + Lu) where i: position of branch n: position of branch Number P: Transmission power from controller Pt: Transmission power to antenna Pw: Received power from antenna Ls: Loss of one section on trunk cable Lu: Loss on branch cable

As described above, by setting the distribution ratio of each branch, a substantially constant power Pt is supplied to each of the antennas 32 to 36, so that the position of the antenna relative to the detected object Obj is Irrespective of this, a substantially constant electromagnetic pulse can be emitted.

Therefore, even when the transmission loss increases as the length of the trunk cable increases, the power of the radio wave radiated to the detected object such as a vehicle does not decrease.
Radio waves can be stably emitted. For this reason, the high-frequency pulse signal transmitted to the antenna having a difference in the length of the trunk cable is stable, and the power of the return signal does not decrease, so that the detected object such as a vehicle can be easily detected. it can. As described above, the power of the high-frequency pulse signal input to the antenna becomes constant regardless of the length of the backbone cable, and a stable high-frequency pulse signal can be obtained.

Here, when the detected object Obj exists at a position facing the antenna 36, the detected object Obj
An electromagnetic wave pulse 46 is radiated, and the reflected wave 56 is received by the antenna 36, and the main cable 10 is transmitted as the reflected wave 20 </ b> B via the branch cable 26 and the branch portion 16 to reach the controller 40. The reflected wave 20B is a detection signal for detecting the presence or absence of the detected object Obj in the controller 40.

As shown in FIG. 3, the details of the detection are shown in FIG.
The high frequency pulse signal 18 shown in FIG.
Is generated and output. FIG. 3B shows the antenna 32.
FIG. 5 shows a detectable range that appears when the reflection by the electromagnetic wave pulse 42 emitted from is detected. When the detected object Obj exists at a position facing the antenna 32, a pulse signal due to a reflected wave exists during a time interval T1 from time t1 after the output of the high-frequency pulse signal 18. The time t1 is the time required for the high-frequency pulse signal to be transmitted (reciprocated) between the controller 40 and the antenna 32, and the time interval T1 is the time interval T1 between the antenna 32 and the detected object Obj.
Is the time required for the electromagnetic wave pulse 42 (reflected wave 52) to be transmitted (reciprocated).

The time interval T1 can be set in advance. That is, as the detected object Obj moves away from the antenna 32, the signal received by the antenna 32 becomes weaker. For this reason, the detection becomes impossible if a certain distance is separated, so that the detection range of the detected object Obj is determined. The time interval T1 corresponds to this detection range. Therefore, if a pulse signal exists within the time interval T1, it can be determined that the detected object Obj exists.

Similarly, FIG. 3C shows the reflection (reflected wave 54) by the electromagnetic wave pulse 44 radiated from the antenna 34.
FIG. 3D shows a detectable range that appears when detecting the reflection (reflected wave 56) due to the electromagnetic wave pulse 46 radiated from the antenna 36. It is a thing. Antenna 34
When the detected object Obj exists at a position opposite to the time t2, the time interval T
2, there is a pulse signal due to the reflected wave, and the antenna 3
In the case where the detected object Obj exists at a position opposite to the position No. 6, a pulse signal due to a reflected wave exists during a time interval T3 from time t3 after the output of the high-frequency pulse signal 18.

In the example of FIG. 1, since the detected object Obj exists at a position facing the antenna 36, a pulse signal due to a reflected wave exists during a time interval T3 from the time t3 after the output of the high-frequency pulse signal 18. .

As described above, the presence or absence of the detected object Obj can be determined based on the time difference between the pulse signals. However, when the determination is delicate, that is, at times t1, t2, and t3.
May be small. In this case, the antenna,
Branch cable and trunk cable 10 to branch cable
May be adjusted. Since it is not easy to change the length of the trunk cable 10, the length of the branch cable from each antenna is adjusted. Therefore, by adjusting the length of the branch cable from each antenna to make the transmission path length difference easily detectable, appropriate differences can be obtained at times t1, t2, and t3, and each antenna can be easily set. Can be determined as to whether or not the detected object Obj exists at a position corresponding to.

As described above, in this embodiment, the power of the high-frequency pulse signal input to the antenna is constant irrespective of the length of the trunk cable, and a stable high-frequency pulse signal can be obtained. It is possible to easily determine the presence or absence of the detected object Obj at a position facing each antenna.

Next, a case will be described in which the present invention is applied to a vehicle detection device 60 for detecting the presence or absence of a vehicle using the above detection principle.

As shown in FIG. 4, the vehicle detection device 60
In the lower part (underground) of the traveling path 70 composed of the lanes 72, 74, and 76, one branch cable 12,
Three antennas 32, 34, 36 connected in an array via 14, 16 and branch cables 22, 24, 26
Is buried. A controller 40 that controls the output of the high-frequency pulse signal is connected to one end of the trunk cable 10.

The antennas 32, 34, 36
It is buried corresponding to 74 and 76. The trunk cable 10 is buried so as to cross the travel path 70 (lanes 72, 74, 76).

As shown in FIG. 5, in the detection, FIG.
Is generated by the controller 40 and output. In the example of FIG. 4, the lane 72 and the lane 7
6, vehicles 62 and 66 are present. As shown in FIG. 5B, the electromagnetic wave pulse 42 radiated from the antenna 32
The reflected pulse exists after approximately time t1 after the output of the high-frequency pulse signal 18. Further, as shown in FIG. 5C, there is no reflected pulse due to the electromagnetic wave pulse radiated from the antenna. As shown in FIG. 5D, the reflected pulse due to the electromagnetic wave pulse radiated from the antenna 36 exists after approximately time t3 after the output of the high-frequency pulse signal 18.

Therefore, the reflected pulses due to the electromagnetic wave pulses radiated from each antenna are combined at the branch portions 12, 14, and 16, and become a signal having two pulses as shown in FIG. 5 (E). The number of existing vehicles can be detected by counting the number of these pulse signals, and the position of the vehicle can be detected by measuring the time difference between each pulse signal and the high-frequency pulse signal 18.

As described above, since the antenna is connected to the trunk cable via the branch cable, the installation and wiring of spot-type vehicle sensors such as ultrasonic waves and loop coils are not performed and the input to the antenna is performed at low cost. It is possible to construct a device in which a high-frequency pulse signal is stabilized.

Further, even when the detection is delicate between the sensors, it is possible to easily differentiate by adjusting the branch cable length. The presence or absence of a vehicle facing each antenna can be determined. Also in this case, the power of the high-frequency pulse signal input to the antennas can be kept constant regardless of the length of the backbone cable, and the presence or absence of a vehicle facing each antenna can be easily determined.

Further, since an antenna can be connected to the main cable via a branch cable, an arbitrary detection point can be set, for example, in a parking lot. In a parking lot, a plurality of vehicles stop or park in a certain area. When grasping the status of the parking lot (full / vacant), it manages the presence or absence of empty space as the whole parking lot and displays guidance to the driver who seeks a parking lot (outside the parking lot), and displays each parking lot. It manages the full / vacant state of the space and guides and guides the driver in the parking lot.

Therefore, an arbitrary detection point can be freely arranged in accordance with the shape of the parking lot, and the detection points can be connected in a single stroke with a backbone cable. Can be grasped (full / vacant), so that vehicle guidance in the parking lot can be realized very easily, and an efficient and safe parking lot system can be realized at low cost.

FIG. 6 shows an example of a parking lot. This parking lot 80 has a plurality of parking spaces 82, 84, 86, 88.
A, 88B, 88C, 88D, and 88E. Each parking space has antennas 32, 34, 3
6, 38A, 38B, 38C, 38D, 38E are buried. Each of these antennas 32 to 38E is connected to the main cable 10 via a branch cable.
The branch cables serving as these branch cables and the connecting portions are the same as described above. The controller 4 of the backbone cable 10
A terminator 39 for suppressing reflection in the main cable 10 is connected to an end opposite to the end connected to zero. The controller 40 grasps the situation of each parking space, displays guidance to a driver who needs a parking lot (outside the parking lot), manages the full / vacant state of each parking space, and drives in the parking lot. A control device 41 for guiding and guiding a person is connected.

As described above, it is possible to provide a very simple configuration in which arbitrary detection points are freely arranged in accordance with the shape of the parking lot, and the detection points are connected by a single stroke with a main cable. Since the situation of each parking space can be ascertained (full / empty), vehicle guidance in the parking lot can be realized extremely easily, and an efficient and safe parking system can be realized at low cost. In addition, since the vehicle position detection can output "where and how many vehicles exist" to an arbitrary area, not only to a specific point, it is possible to increase the degree of freedom of the application after the vehicle detection. Can be.

[Second Embodiment] Next, a second embodiment will be described. Since this embodiment has substantially the same configuration as that of the above-described embodiment, the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

In the above embodiment, the distribution ratio of each branch is set. However, setting the distribution ratio of each branch individually involves complicated work as the number of branches increases. Therefore, in the present embodiment, a substantially constant power Pt is supplied to each antenna by attenuating the signal transmitted through the branch cable with the distribution ratio of the branch portion being substantially the same.

In this embodiment, a case is described in which a substantially constant power Pt is supplied to each antenna by attenuating a signal. However, the present invention is not limited to signal attenuation, and amplifies a signal. Thus, a substantially constant power Pt may be supplied to each antenna.

First, a description will be given of a detection principle in the present embodiment in which transmission loss for detecting the presence / absence of an object by radio wave radiation and its reflection is considered.

As shown in FIG. 7, in the vehicle detection device of this embodiment, one trunk cable 10 is provided with branch portions 12, 14, and 16 having a fixed distribution ratio.
Attenuators 28A, 28B, and 28 are provided between each of antennas 2 to 16 and antennas 32 to 36, that is, on branch cables 22 to 26.
28C are provided.

Since the branching portions 12 to 16 have a fixed distribution ratio, if the branch cable is connected to the antenna as it is, a signal is supplied with different power. Thus, by setting the attenuation rate of each of the attenuators 28A, 28B, 28C, a substantially constant power Pt is supplied. The attenuation ratios of these attenuators 28A to 28C are set in advance so that substantially constant power Pt is supplied to each antenna. The attenuation rate ATT of the attenuator connected to the i (≧ 1) -th branch can be expressed by the following equation (2).

Attenuation rate ATT of the attenuator belonging to the i-th antenna ATT ATT = (ni) × (Ls + C) [dB] (2) where C: 10 · log 2

As described above, by setting the attenuation rate of the attenuator continuous to each branch, each of the antennas 32 to 3 is set.
6 is supplied with a substantially constant power Pt, so that the detected object Obj is not related to the position of the antenna.
A substantially constant electromagnetic wave pulse can be emitted.

Therefore, even if the transmission loss increases as the length of the backbone cable increases, the power of the radio wave radiated to the detected object such as a vehicle does not decrease.
Radio waves can be stably emitted. For this reason, the high-frequency pulse signal transmitted to the antenna having a difference in the length of the trunk cable is stable, and the power of the return signal does not decrease, so that the detected object such as a vehicle can be easily detected. it can. As described above, the power of the high-frequency pulse signal input to the antenna becomes constant regardless of the length of the backbone cable, and a stable high-frequency pulse signal can be obtained.

[Third Embodiment] Next, a third embodiment will be described. Since this embodiment has substantially the same configuration as that of the above-described embodiment, the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

In the first embodiment, a substantially constant power Pt is supplied to each antenna by setting the distribution ratio of each branch.
, But a signal (feedback signal) output from an antenna that has received a radio wave retroreflected by the detected object Obj
Attenuates in the transmitted cable, i.e., the branch cable and the backbone cable. Therefore, in the present embodiment, the signal output from the antenna is stably supplied to the controller as a signal having substantially constant power.

First, a description will be given of a detection principle in the present embodiment in consideration of a transmission loss of a signal for radio wave radiation and a reflected signal caused by retroreflection by the detected object Obj.

As shown in FIG. 8, in the vehicle detection device according to the present embodiment, the trunk cable 10 is provided with branch portions 12, 14, and 16 capable of setting a distribution ratio.
-16 are provided with antennas 32, 34, 36 connected via branch cables 22, 24, 26, respectively. A controller 40 that controls the output of the high-frequency pulse signal is connected to one end of the trunk cable 10. A terminator 39 is connected to the other end of the trunk cable 10.

In the following description, as in the first embodiment, a case where a transmission signal is branched into three from one trunk cable 10 will be described. However, the transmission signal is divided into two or four or more transmission signals. The present invention can also be applied to branching.

Each of the branch cables 22, 24, 26 is provided with a circulator 48A, 50A, a circulator 48B, 50B, and a circulator 48C, 50C. Each of the circulators 48A and 50A is connected to both ends of a branch cable 23 having an attenuator 30A whose attenuation rate can be set. Similarly, each of the circulators 48B and 50B is connected to both ends of a branch cable 25 having an attenuator 30B whose attenuation rate can be set, and each of the circulators 48C and 50C has an attenuator whose attenuation rate can be set. Both ends of the branch cable 27 having 30C are connected.

The forward traveling wave 20F (high-frequency pulse signal) output and transmitted from the controller 40 is
In step 2, the signal is distributed to the branch cable 22 at a preset ratio and transmitted through the branch cable 22 to reach the antenna 32. This traveling wave 20F passes through the circulators 48A and 50A as they are. Then, the reflected wave 20B (high-frequency pulse signal) on the return path, that is, the reflected signal due to the detected object Obj, which is reflected and received by the antenna 32 and reflected by the antenna 32, is fed back, and the reflected wave 20B is transmitted to the circulator 48A. Is output to the branch cable 23 and is attenuated to a constant power by the attenuator 30A whose attenuation rate is set, and coupled to the branch cable 22 by the circulator 50A. The signal of the attenuated reflected wave 20B is coupled only in the direction toward the controller 40 at the branching unit 12. Therefore, a signal effective only for detection without causing the reflected wave 20B to interfere with the traveling wave 20F is generated by the controller 40.
Will be returned to.

For example, the antenna 36 shown in FIG. 8 will be described. The radio wave radiated from the antenna 36 in response to the traveling wave 20F input at a predetermined power Pt
j, the reflected radio wave (reflected wave 56) is received by the antenna 36 and output with the power Pw, and the branch cable 26, the branch cable 27, the attenuator 30C, and the branch 1
6, the main cable 10 is transmitted as a reflected wave 20B and reaches the controller 40.

In this embodiment, a case is described in which a substantially constant power Pt is supplied to each antenna by attenuating a signal. However, the present invention is not limited to signal attenuation, and amplifies a signal. Thus, a substantially constant power Pt may be supplied to each antenna.

Here, the attenuators 30A, 30B and 30C will be described.

The distribution ratios of the branching units 12 to 16 are set so that the powers reaching the antennas are substantially the same, and the reflected waves have substantially the same power. However, the power of the signal received by the controller differs according to the length of the transmitted cable. Therefore, by setting the attenuation rate of each of the attenuators 30A, 30B, and 30C acting only on the reflected wave, the controller 40 controls the power P to be substantially constant.
w. That is, the attenuation ratios of these attenuators 30A to 30C are set in advance so that substantially constant power Pt is supplied to controller 40.
Attenuation rate A of the attenuator connected to the i-th (≧ 1) branch
TT can be represented by the following equation (3).

The attenuation factor ATT of the attenuator belonging to the i-th antenna

(Equation 1) Where j is a variable

As described above, by attenuating the power of the reflected wave from each of the branch portions for which the distribution ratio is set,
A substantially constant power Pt is supplied to each of the antennas 32 to 36 so that a radio wave having a substantially constant power can be radiated to the detected object Obj regardless of the position of the antenna, that is, the cable length. The radio wave reflected from the antenna can be supplied to the controller 40 with substantially constant power.

Therefore, even if the transmission loss increases as the length of the backbone cable increases, the power of the radio wave radiated to the detected object such as a vehicle does not decrease.
Radio waves can be stably radiated, and the power of the radio waves of the reflected waves from the detected object such as the detected vehicle can be supplied to the controller without lowering. For this reason, the high-frequency pulse signal transmitted to the antenna having a difference in the length of the trunk cable is stable, and the power of the return signal does not decrease, so that the detected object such as a vehicle can be easily detected. it can. As described above, the power of the high-frequency pulse signal input to the antenna and the power of the feedback signal from the antenna become constant regardless of the length of the backbone cable, and a stable signal can be obtained.

[Fourth Embodiment] Next, a fourth embodiment will be described. Since this embodiment has substantially the same configuration as that of the above-described embodiment, the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

In the second embodiment, a substantially constant power Pt is supplied to each antenna by setting the distribution ratio of each branch section to be constant and providing an attenuator to set the attenuation rate.
In the present embodiment, an attenuator is provided on each of the forward path and the return path of a signal to be transmitted, and the power of the radio wave supplied to the antenna is made substantially constant, and the signal output from the antenna is made a signal having a substantially constant power. This is a stable supply to the controller.

As shown in FIG. 9, in the vehicle detection device according to the present embodiment, the trunk cable 10 is provided with branch portions 12, 14, and 16 having a fixed distribution ratio.
-16 are provided with antennas 32, 34, 36 connected via branch cables 22, 24, 26, respectively. A controller 40 that controls the output of the high-frequency pulse signal is connected to one end of the trunk cable 10. A terminator 39 is connected to the other end of the trunk cable 10.

In the following description, as in the first embodiment, a case where a transmission signal is branched into three from one trunk cable 10 will be described. However, the transmission signal is divided into two or four or more transmission signals. The present invention can also be applied to branching.

Each of the branch cables 22, 24, 26 is provided with a circulator 48A, 50A, a circulator 48B, 50B, and a circulator 48C, 50C. Each of the circulators 48A and 50A is connected to both ends of a branch cable 23 having an attenuator 30A whose attenuation rate can be set. Similarly, each of the circulators 48B and 50B is connected to both ends of a branch cable 25 having an attenuator 30B whose attenuation rate can be set, and each of the circulators 48C and 50C has an attenuator whose attenuation rate can be set. Both ends of the branch cable 27 having 30C are connected.

An attenuator 28A is provided on the branch cable 22, that is, between the circulators 48A and 50A. Similarly, an attenuator 28B is provided on the branch cable 24 (between the circulators 48B and 50B), and is provided on the branch cable 26 (circulators 48C and 50B).
C), an attenuator 28C is provided.

The forward traveling wave 20F (high-frequency pulse signal) output from the controller 40 and transmitted is transmitted to the branch unit 1
The distribution is distributed to the branch cable 22 at a fixed ratio of 2 and transmitted through the branch cable 22 to reach the antenna 32. When transmitted through the branch cable 22, the power of the signal is attenuated by the attenuator 28A, and a radio wave having a constant power is radiated from the antenna. The traveling wave 20F is supplied to the circulators 48A and 50A.
Pass through A as it is. Then, the reflected wave 20B (high-frequency pulse signal) on the return path, which is the reflection of the electromagnetic wave pulse radiated from the antenna 32 and received and transmitted by the antenna, that is, the reflection signal caused by the retroreflection by the detected object Obj is fed back, The reflected wave 20B is output to the branch cable 23 by the circulator 48A and is attenuated to a constant power by the attenuator 30A whose attenuation rate is set, and is coupled to the branch cable 22 by the circulator 50A. The signal of the attenuated reflected wave 20B is coupled only in the direction toward the controller 40 at the branching unit 12. Therefore, a signal effective only for detection is returned to the controller 40 without the reflected wave 20B interfering with the traveling wave 20F.

In this embodiment, a case will be described where a substantially constant power Pt is supplied to each antenna by attenuating the signal. However, the present invention is not limited to the signal attenuation, and the signal is amplified. Thus, a substantially constant power Pt may be supplied to each antenna.

As described above, by setting the attenuation rate of the attenuator continuous to each branch, each of the antennas 32 to 3 is set.
6 is supplied with a substantially constant power Pt, and transmits a radio wave reflected from the antenna with a substantially constant power to the controller 4.
0, it is possible to easily detect the presence / absence of the detected object Obj regardless of the position of the antenna.

Therefore, even when the transmission loss increases as the length of the trunk cable increases, the power of the radio wave radiated to the detected object such as a vehicle does not decrease.
The radio wave can be stably emitted, and the power of the radio wave of the reflected wave from the detected object such as the detected vehicle can be supplied to the controller without lowering. For this reason,
Since the high-frequency pulse signal transmitted to the antenna having a different length of the trunk cable is stable and the power of the feedback signal is set to be constant, a detected object such as a vehicle can be easily detected. As described above, the power of the high-frequency pulse signal becomes constant regardless of the length of the main cable, and a stable high-frequency pulse signal can be obtained.

[Fifth Embodiment] Next, a fifth embodiment will be described. In the present embodiment, a traveling wave and a reflected wave are transmitted by independent cables. Since this embodiment has substantially the same configuration as that of the above-described embodiment, the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

As shown in FIG. 10, the vehicle detecting device 61 of the present embodiment has trunk cables 10A and 10B buried in the lower part (underground) of the traveling path 70. The distribution section 12A, the branch cable 22A,
The antenna 32 is connected via the circulator 92 and the branch cable 22. Similarly, the backbone cable 10
A includes an antenna 34 via a distribution unit 14A, a branch cable 24A, a circulator 94, and a branch cable 24.
Are connected, and the antenna 36 is connected via the distribution unit 16A, the branch cable 26A, the circulator 96, and the branch cable 26. Circulators 92, 94, 9
Each of 6 is connected to the main cable 10B via each of the branch cables 22B, 24B, 26B and the joints 12B, 14B, 16B. Backbone cable 10A, 1
The controller 40 is connected to one end of OB.

The distribution units 12A, 14A, and 16A distribute the high-frequency pulse signal output from the controller 40 to the distribution cables at a predetermined ratio, and the coupling units 12B, 14B, and 16B return as reflected waves. This is for combining the electromagnetic pulse signals and returning them to the controller 40. Therefore, the distribution unit does not need to be a directional coupler as in the above embodiment, but may be a device that can simply distribute. In addition, since the coupling section needs to couple the reflected waves, it is preferable to use the directional coupler used for the branch section in the above embodiment.

In this embodiment, the supply section 68A is constituted by the distribution section 12A connected to the main cable 10A and the branch cable 22A. Similarly, distribution unit 1
4A and the branch cable 24A, the supply unit 68B
And the distribution unit 16A and the branch cable 26A constitute a supply unit 68B. These supply units include a main cable 10A and branch cables 22A to 26A.
The power of the signal is adjusted in order to supply a substantially constant power Pt to each of the antennas 32 to 36 in consideration of the attenuation by A.

That is, as described in the first embodiment, the distribution ratio at the branching unit is determined by the distribution units 12A, 14A,
A substantially constant power Pt is supplied to each of the antennas 32 to 36 by setting each of the antennas 16A and providing an attenuator on the branch cables 22A, 24A and 26A as described in the second embodiment. .

The branch cables 22B, 24B, 26
Each of B is provided with an adjusting unit 78A, 78B, 78C. These adjustment units 78A to 78C are configured to control the return signal with the main cable 10A and the branch cables 22A to
The power of the signal is adjusted in order to provide the signal from each of the antennas 32 to 36 to the controller 40 at a substantially constant power Pw in consideration of the attenuation due to 26A.

That is, as described in the third and fourth embodiments, the branch cables 22B, 24B,
An attenuator is provided on 26B to provide the controller 40 with a substantially constant power Pw.

In the present embodiment, a case will be described in which an adjusting unit is provided to provide substantially constant power Pw to the controller 40. However, without providing an adjusting unit, the coupling unit 12B,
By setting the coupling ratio to each of 14B and 16B, substantially constant power Pw may be provided to controller 40.

The high-frequency pulse signal generated and output by the controller 40 is transmitted through the main cable 10, distributed by the distribution unit 12A, transmitted through the branch cable 22A, transmitted through the circulator 92 and the branch cable 22, and transmitted through the antenna 32. , And an electromagnetic wave pulse 42 is emitted from the antenna 32. The power of the radio wave transmitted to this antenna is set substantially constant for each antenna.
As a result, it is possible to radiate a substantially constant electromagnetic wave pulse to the detected object Obj irrespective of the position of the antenna, that is, without being affected by attenuation due to the cable length.

When the detected object Obj is present at a position opposite to the antenna 32, the electromagnetic wave pulse 42 is reflected, the reflected wave 52 is received by the antenna 32, and transmitted through the branch cable 22 to reach the circulator 92. . In the circulator 92, the reflected wave is transmitted to the branch cable 22A.
Output to the branch cable 22B without returning to the branch cable 22B. In the branch cable 22B, a substantially constant power Pw is supplied to the controller 40.
The power is adjusted so that is provided and output. The signal transmitted through the branch cable 22B is connected to the coupling unit 12B.
Via the trunk cable 10B to reach the controller 40. Thus, the controller 40 can detect a substantially constant signal with respect to the detected object Obj, regardless of the position of the antenna, that is, without being affected by attenuation due to the cable length.

As shown in FIG. 11, the forward high-frequency pulse signal output and transmitted from the controller 40 is transmitted by the traveling wave 20F and the reflection of the electromagnetic pulse radiated from the antenna 32 is received by the antenna and transmitted by the antenna. If the pulse signal is a reflected wave 20B, the traveling wave 20F is
At 2A, the signal is distributed to the branch cable 22A at a preset distribution ratio, transmitted through the branch cable 22, and a reflected wave 20B, which is a reflection thereof, returns. This reflected wave 20B is output to the branch cable 22B by the circulator 92, and
In 2B, the signals are combined only in the direction toward the controller 40. Therefore, a signal effective only for detection is returned to the controller 40 without the reflected wave 20B interfering with the traveling wave 20F.

Similarly, the high-frequency pulse signal generated and output by the controller 40 is transmitted through the trunk cable 10, distributed by the distribution units 14A and 16A, transmitted through the branch cables 24A and 26A, and circulators 94 and 96.
And transmitted through the branch cables 24 and 26 and the antenna 3
4, 36, and electromagnetic waves 44, 46 are radiated from the antennas 34, 36. When the detected object Obj exists at a position facing the antennas 34 and 36, the electromagnetic wave pulses 44 and 46 are reflected, and the reflected waves 54 and 5 are reflected.
6 are received by the antennas 34 and 36, and the branch cable 24,
26 is transmitted to circulators 94 and 96. In the circulators 94 and 96, the reflected waves are not returned to the branch cables 24A and 26A, and the branch cables 24B and
26B. The signal transmitted through the branch cables 24B and 26B is transmitted through the trunk cable 10B via the coupling sections 14B and 16B and reaches the controller 40.

As described above, according to the present embodiment, the cables through which the traveling wave and the reflected wave are transmitted are separated.
Each signal can be made independent, and it is easy to determine the presence or absence of the vehicle.

In the above embodiment, the case where the vehicle detection device is buried underground has been described. However, the present invention is not limited to this. For example, it may be installed on the ground surface. Further, a part of the device may be buried underground. In this case, at least only the antenna and a necessary and sufficient branch cable may be embedded.

In the above embodiment, the case where the present invention is applied to a parking lot has been described. However, the present invention can be used for detecting a vehicle such as an AHS. In AHS, vehicle detection becomes important. In other words, the AHS vehicle travels at a constant interval while detecting the surrounding vehicles of the own vehicle with its own sensor. However, in the event of an accident or the like, there is a possibility that the avoidance operation may not be in time when the abnormality of the surrounding vehicle is detected. There is. Therefore, the position and speed of each vehicle on the road are detected, and an accident is predicted or detected from a change in the behavior of the vehicle.
A ground system for transmitting to an S car is considered indispensable.
This vehicle can be easily detected by using an area sensor such as an image sensor. There is also a problem that a portion is generated (so-called shadowing), and it is practically difficult. Further, as described above, it is more impractical to detect a vehicle by arranging spot-type vehicle sensors side by side than to apply it to the parking lot. For this reason, the vehicle detection device of the present embodiment is extremely useful.

In the above embodiment, the case where a vehicle is used as an object to be detected has been described. However, the present invention is not limited to only a vehicle, and can be applied to object detection such as a robot or a moving object. It is.

[0113]

As described above, according to the present invention, the power of at least one of the high-frequency pulse signal and the feedback signal transmitted through the trunk cable is adjusted to a predetermined power. There is an effect that an object to be detected in the vicinity of each of the plurality of antennas can be reliably detected regardless of the length of the branch cable.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining the principle of vehicle detection according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining an operation of the directional coupler according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a high-frequency signal that changes according to the presence or absence of a vehicle.

FIG. 4 is a block diagram illustrating a schematic configuration of a vehicle detection device according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a high-frequency signal.

FIG. 6 is a block diagram for explaining a specific example when the vehicle detection device is applied to a parking lot.

FIG. 7 is an explanatory diagram for explaining a principle of vehicle detection according to a second embodiment of the present invention.

FIG. 8 is an explanatory diagram for explaining the principle of vehicle detection according to a third embodiment of the present invention.

FIG. 9 is an explanatory diagram for explaining the principle of vehicle detection according to a fourth embodiment of the present invention.

FIG. 10 is a block diagram illustrating a schematic configuration of a vehicle detection device according to a fifth embodiment of the present invention.

FIG. 11 is an explanatory diagram for explaining an operation around a directional coupler according to a fourth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 backbone cable 40 controller 12, 14, 16 branching section 22, 24, 26 branch cable 32, 34, 36 antenna

Continuing on the front page (72) Inventor Kazuo Shishikura 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Kazuyuki Seo 3-30 Shimo Market Town Toyota City, Aichi Prefecture Kojima Press Kogyo Co., Ltd. (72) Inventor Satoshi Hori 3-30 Shimoichimachi, Toyota City, Aichi Prefecture Kojima Press Industry Co., Ltd. F term (reference) 2G005 DA04

Claims (12)

[Claims] 1. A plurality of antennas for detecting radiation of a radio wave according to an input high-frequency pulse signal and reflection of the radiated radio wave and outputting it as a feedback signal; one trunk cable; and the plurality of antennas One end is connected to each of
A plurality of branch cables, the other ends of which are connected to the trunk cable; a plurality of adjusting means provided on each of the branch cables, for adjusting an input signal to a signal of a predetermined power; Output means for outputting a high-frequency pulse signal to the trunk cable, detecting the feedback signal, and receiving signals near each of the plurality of antennas based on the detected feedback signal. An object detection device, comprising: detection means for detecting a detection object. 2. The apparatus according to claim 1, wherein said adjusting means adjusts a high-frequency pulse signal transmitted to said antenna to a high-frequency pulse signal having a predetermined power.
An object detection device according to claim 1. 3. The object detection device according to claim 1, wherein the adjustment unit includes an attenuator that attenuates the power of the input high-frequency pulse signal. 4. The object detection device according to claim 1, wherein the adjustment unit adjusts a feedback signal from the antenna to a feedback signal having a predetermined power. 5. The apparatus according to claim 2, further comprising a feedback signal adjusting means provided on each of said branch cable and adjusting a feedback signal from said antenna to a feedback signal having a predetermined power. 4. The object detection device according to 3. 6. The object detection device according to claim 5, wherein the feedback signal adjusting unit includes a plurality of circulators for separating the high-frequency pulse signal and the feedback signal, each of the branch cables. . 7. The object detecting device according to claim 5, wherein the feedback signal adjusting means comprises an attenuator for attenuating the power of the feedback signal. 8. The vehicle according to claim 1, wherein the trunk cable is buried in a direction transverse to a traveling path of the vehicle, and each of the plurality of antennas is installed corresponding to each lane. 2. The object detection device according to claim 1. 9. The vehicle according to claim 6, wherein the trunk cable is embedded in a vehicle area including a plurality of exclusive areas specific to the vehicle, and each of the plurality of antennas is installed in each of the exclusive areas specific to the plurality of vehicles. Any one of claims 1 to 8
Item detection device according to Item. 10. A plurality of antennas for radiating radio waves according to an input high-frequency pulse signal, detecting reflections of the radiated radio waves and outputting them as feedback signals, and a traveling wave for transmitting at least a high-frequency pulse signal. A backbone cable group consisting of a cable and a reflected wave cable for transmitting the return signal, and one end connected to each of the plurality of antennas,
A plurality of branch cables connected to each of the traveling wave cable and the reflected wave cable of the trunk cable group, and the other end is provided in each of the branch cables and provided in each of the branch cables and input. A plurality of adjusting means for adjusting a signal to a signal of a predetermined power; an output means connected to the trunk cable group to output a high-frequency pulse signal to the trunk cable; and a feedback means connected to the trunk cable group. An object detection device, comprising: detection means for detecting a signal and detecting an object to be detected near each of the plurality of antennas based on the detected feedback signal. 11. The object detecting device according to claim 10, wherein each of the branch cables includes a circulator for separating the high-frequency pulse signal and a feedback signal. 12. Each of the branch cables is connected to a traveling wave cable of the trunk cable group by a distributor for distributing a high-frequency pulse signal transmitted through the traveling wave cable, and is connected to the trunk by a directional coupler. 12. A cable connected to a reflected wave cable of a cable group.
An object detection device according to claim 1.