JP2015102499A - Object detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an object detection system that can detect an object and has a simple configuration.SOLUTION: The object detection system (1) includes a plurality of communication devices (BS1-8) capable of performing at least one of transmission and reception of an electric wave, and has a plurality of links formed of the communication devices for transmitting electric wave and the communication devices for receiving the electric wave. The communication device for receiving the electric wave includes position detecting means (7) for detecting the position of the object existing between the links on the basis of the reception state of the electric wave transmitted by the communication device belonging to the same link.

Description

  The present invention relates to an object detection system.

  Conventionally, the following systems have been proposed to prevent accidents at intersections with poor visibility. A laser radar and camera capable of detecting a vehicle traveling on one road leading to the intersection will be installed. In addition, a display that can be seen from the other road leading to the intersection is installed. When a vehicle traveling on one road is detected by a laser radar or a camera, an indicator lamp is turned on to alert the vehicle traveling on the other road (see Patent Document 1).

JP 2012-8753 A

  In the system described in Patent Document 1, since an autonomous sensor (laser radar, camera, etc.) is used, the system is complicated and expensive. This invention is made | formed in view of the above point, and it aims at providing the object detection system which can solve the subject mentioned above.

  The object detection system of the present invention includes a plurality of communication devices capable of at least one of transmission and reception of radio waves, and there are a plurality of links including a communication device that transmits radio waves and a communication device that receives the radio waves. .

  In the object detection system of the present invention, the communication device that receives radio waves is a position detection unit that detects the position of an object existing between the links based on the reception state of the radio waves transmitted by communication devices belonging to the same link. Is provided.

According to the object detection system of the present invention, an object (for example, a vehicle) can be detected by a simple system.
In the object detection system of the present invention, the communication device that receives radio waves includes, for example, a size estimation unit that estimates the size of an object based on the two or more positions when the two or more positions are detected. it can. In this case, the size of the object can be estimated.

  In the object detection system of the present invention, the communication device that receives radio waves can include, for example, a speed estimation unit that estimates a moving speed of the object based on a change with time of the position detected by the position detection unit. In this case, the moving speed (speed and moving direction) of the object can be estimated.

  In the object detection system of the present invention, the communication device that receives radio waves can include, for example, a detection result transmission unit that transmits a detection result of the position detection unit to another communication device. In this case, other communication apparatuses can execute various processes using the received detection results.

  In the object detection system of the present invention, at least a part of the communication device that receives radio waves can transmit radio waves, for example, and when the position is detected by the position detection means, the reach of the radio waves to be transmitted is widened. Can do. In this case, since a finer mesh is formed by the set of links, the object detection accuracy is improved.

  In the object detection system of the present invention, at least a part of the communication device that receives radio waves can include, for example, a light emitting unit that emits light based on a detection result of the position detection unit. In this case, the presence of the object can be notified by the light emission of the light emitting means.

  In the object detection system of the present invention, the light emitting means can change the light emission amount according to the positional relationship between the position of the object detected by the position detecting means and a predetermined reference position, for example. In this case, the position of the object can be notified by the light emission amount.

  In the object detection system of the present invention, at least a part of the communication device can be installed, for example, on the roadside (on the road or at a position off the road and in the vicinity of the road). In this case, an object (for example, a vehicle) existing on the road can be easily detected.

  In the object detection system of the present invention, at least a part of the communication device can be, for example, an in-vehicle device mounted on a vehicle. In this case, it is possible to detect a bike or bicycle that passes between vehicles.

1 is an explanatory diagram illustrating a configuration of an object detection system 1. FIG. It is a block diagram showing the structure of communication apparatus BS1. It is explanatory drawing showing the structure of communication apparatus BS1. It is explanatory drawing showing the information contained in the electromagnetic wave which the transmission part 3 transmits. It is a flowchart showing the process which communication apparatus BS6 performs. It is explanatory drawing showing a position candidate table. It is explanatory drawing showing the coordinate used with a position candidate table. It is explanatory drawing showing the method of estimating the magnitude | size of an object from a some position candidate. Is an explanatory view from times t _0, t _1, the position candidates coordinates in t ₂ represents a method of estimating the speed of the object. 1 is an explanatory diagram illustrating a configuration of an object detection system 1. FIG. It is a block diagram showing the structure of communication apparatus BS5,6,7,8. 1 is an explanatory diagram illustrating a configuration of an object detection system 1. FIG. 1 is an explanatory diagram illustrating a configuration of an object detection system 1. FIG. 1 is an explanatory diagram illustrating a configuration of an object detection system 1. FIG. It is a block diagram showing the structure of communication apparatus BS1. 3 is a block diagram showing a configuration of communication devices BS2, 3, 4, 5, 6. FIG. It is explanatory drawing showing the information contained in the electromagnetic wave which the transmission part 3 transmits.

Embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
1. Configuration of Object Detection System 1 The configuration of the object detection system 1 will be described with reference to FIGS. As shown in FIG. 1, the object detection system 1 includes a plurality of communication devices BS1, BS2, BS3, BS4, BS5, BS6, BS7, and BS8. Each communication device is installed on the road side of the road 103 on which the vehicle 101 can travel.

  The communication devices BS1, BS3, BS5, BS7 are arranged on one road side 103A of the road 103 at intervals of 20 m along the traveling direction of the road 103. Further, the communication devices BS2, BS4, BS6, BS8 are arranged on the opposite road side 103B of the road 103 at intervals of 20 m along the traveling direction of the road 103.

  A straight line passing through the communication devices BS1 and BS2 is orthogonal to the traveling direction of the road 103. Similarly, a straight line passing through the communication devices BS3 and BS4, a straight line passing through the communication devices BS5 and BS6, and a straight line passing through the communication devices BS7 and BS8 are also orthogonal to the traveling direction of the road 103, respectively.

  The road 103 intersects with the road 105, and the communication devices BS 1, BS 2, BS 3, BS 4 are arranged in the intersection 106 between the road 103 and the road 105. The communication devices BS5, BS6, BS7, BS8 are arranged outside the intersection 106.

  The communication devices BS1, BS2, BS3, BS4, BS5, BS6, BS7, BS8 have the same configuration. As a representative of each communication apparatus, the configuration of the communication apparatus BS1 is shown in FIG. The communication device BS1 includes a transmission unit 3, a reception unit 5, an existence range estimation unit 7, a light emitting unit 9, and a directional antenna 11.

  The transmission unit 3 periodically transmits radio waves using the directional antenna 11. The radio wave transmitted by the transmission unit 3 reaches a part (or at least including the communication devices BS2, BS3, BS4) or all of other communication devices. The transmission unit 3 can transmit radio waves in an angle range where other communication devices exist. Alternatively, the transmission unit 3 may transmit a radio wave beam toward another communication apparatus.

  As shown in FIG. 4, the radio wave transmitted by the transmission unit 3 includes, as information, a BSID that is an identification code of a communication device that transmits the radio wave and coordinates of position candidates. The coordinates of the position candidate will be described later. The intensity of the radio wave transmitted by the transmitter 3 is always constant.

  The receiving unit 5 uses the directional antenna 11 to receive a radio wave transmitted from another communication device using the transmitting unit 3. As described above, since the received radio wave includes the identification code BSID, the communication device that has received the radio wave can identify the communication device that has transmitted the radio wave.

The existence range estimation unit 7 is configured by a well-known computer, and controls each unit of the communication device BS1 to execute processing to be described later.
As shown in FIG. 3, the light emitting unit 9 includes a plurality of LED lamps 9A, 9B, 9C provided on the surface of the housing 13 of the communication device BS1. The LED lamp 9A is provided at a position near the communication device BS2 on the upper surface of the housing 13, the LED lamp 9B is provided at a position near the communication device BS3, and the LED lamp 9C is located near the communication device BS4. Is provided. That is, the light emitting unit 9 includes a number of LED lamps equal to the number of communication devices adjacent to the communication device BS1, and each LED lamp is associated with one adjacent communication in the housing 13, respectively. It is arranged at a position near the device.

  The existence range estimation unit 7 is an embodiment of a position detection unit, a size estimation unit, and a speed estimation unit. Moreover, the transmission part 3 and the existence range estimation part 7 are one Embodiment of a detection result transmission means. Further, the existence range estimation unit 7 and the light emitting unit 9 are an embodiment of a light emitting unit.

Each communication device included in the object detection system 1 forms a link with a plurality of surrounding communication devices. Here, the link means a combination of one communication device that transmits radio waves and one communication device that receives the radio waves. For example, as shown in FIG. 1, the communication device BS6 forms links with the communication devices BS3, BS4, BS5, BS7, and BS8, respectively. Similarly, communication devices other than the communication device BS6 form a link with surrounding communication devices. Hereinafter, a link composed of the communication devices BSn and BSm (n and m are different integers of 1 to 8, respectively) will be denoted as L _nm .

Each link transmits and receives bidirectional radio waves. For example, on the link L _nm , the communication device BSm receives the radio wave transmitted by the communication device BSn, and the communication device BSn receives the radio wave transmitted by the communication device BSm.

2. Processing Performed by Object Detection System 1 Processing performed by the object detection system 1 will be described with reference to FIGS. Each communication device (particularly the existence range estimation unit 7) included in the object detection system 1 repeats the processing shown in FIG. 5 at predetermined time intervals. Here, the communication device BS6 will be described as an example, but the same processing is performed in other communication devices.

In step 1, radio waves transmitted from other communication devices are received using the receiving unit 5. Since the communication device BS6 constitutes the links L ₃₆ , L ₄₆ , L ₅₆ , L ₆₇ , and L ₆₈ , the communication device BS 6 receives radio waves from the communication devices BS 3, BS 4, BS 5, BS 7, and BS 8, respectively.

In step 2, first, the strength R of the radio wave received in step 1 is calculated for each link. That is, the intensity R of the radio wave received at the link L ₃₆ , the intensity R of the radio wave received at the link L ₄₆ , the intensity R of the radio wave received at the link L ₅₆ , the intensity R of the radio wave received at the link L ₆₇ , and the link L ₈₆ The intensity R of the received radio wave is calculated.

As described above, the received radio wave includes the identification code BSID, so that the received radio wave can be identified for each communication device (that is, for each link).
Next, the fluctuation amount ΔR is calculated by subtracting the standard strength R _nm (fixed value) preset for each link from the radio wave strength R calculated as described above. The standard intensity R _nm is the intensity of radio waves when there is no object that blocks radio waves between the links. When the intensity R is smaller than the standard intensity R _nm , the fluctuation amount ΔR is a negative value. The fluctuation amount ΔR is calculated for each link.

In step 3, using the variation amount ΔR calculated in step 2, a position candidate of an object (such as a vehicle) existing on the road is detected. Specifically, this is performed as follows. The communication device BS6 includes a position candidate table shown in FIG. 6 in advance. The position candidate table associates the variation amount ΔR with the coordinates of the position candidate for each link. For example, in the link L ₆₇ , when the variation amount ΔR is 5 to 10 dB, the position candidate coordinates are (−10, 10), and when the variation amount ΔR is 10 to 15 dB, the position candidate coordinates are ( −5, 5) and (−15, 15), and when the fluctuation amount ΔR is 15 dB or more, the coordinates of the position candidate are (0, 0) and (−20, 20).

  Here, as shown in FIG. 7, the above coordinates are coordinates with the position of the communication device BS6 as the origin, the traveling direction of the road 103 as the X axis, and the direction crossing the road 103 as the Y axis. The coordinates of the devices BS4, BS5, BS8 are represented as (20, 0), (0, 20), (−20, 0), respectively.

  The position candidate table is created based on the following principle. That is, when an object is present on the link, the object blocks radio waves transmitted from the communication device on the other side of the link, and the fluctuation amount ΔR in the link becomes a negative value. Therefore, if the fluctuation amount ΔR is a negative value, it can be estimated that there is an object on the link (on the straight line connecting the two communication devices constituting the link). Further, the closer the position of an object existing on the link is to one of the two communication devices constituting the link, the larger the absolute value of the fluctuation amount ΔR in the link. Therefore, when ΔR is 10 dB or more, there are two position candidates as described above.

  In step 4, the transmission unit 3 is used to transmit radio waves to other communication devices. This radio wave includes the identification code BSID of the communication device BS6. Further, the radio wave includes information on the position candidates detected in step 3 (see FIG. 4).

  In step 5, position candidates are extracted from the radio wave received in step 1. This position candidate is a position candidate (see FIG. 4) that is detected in the communication device that is the radio wave transmission source in the same manner as in Step 3 and is included in the radio wave as information.

  In step 6, the position candidates are narrowed down using the position candidates detected in step 3 and the position candidates captured in step 5. Specifically, this is performed as follows. If a position candidate is detected on one link but no position candidate is detected at the same position or a nearby position on another link, the position candidate is not true (actually the position The object is not present in the position candidate.

  On the other hand, if a position candidate is detected on one link and a position candidate is detected on the other link at the same position or a nearby position, the position candidate is true (actually the position The object is left as a position candidate.

  In step 7, based on two or more position candidates, processing for estimating the size of the object is performed as follows. When a predetermined positional relationship (for example, the distance between position candidates is equal to or less than a predetermined value) is established for two or more position candidates remaining after narrowing down in step 6, the two or more position candidates are It is determined that one straddling object exists on the road. Then, the distance between the two or more position candidates is estimated as the size of the object.

For example, as shown in FIG. 8A, when position candidates are detected at coordinates (x ₁ , y ₁ ) and coordinates (x ₂ , y ₂ ) and satisfy a predetermined positional relationship, an object straddling two coordinates It is determined that 107 exists, and the distance between the two coordinates is estimated as the size of the object 107.

Further, as shown in FIG. 8B, position candidates are detected at coordinates (x ₁ , y ₁ ), coordinates (x ₂ , y ₂ ), and coordinates (x ₃ , y ₃ ), respectively, and they have a predetermined positional relationship. When it is satisfied, it is determined that there is an object 109 that straddles three coordinates, and the distance between the two coordinates at both ends is estimated as the size of the object 109.

Returning to FIG. 5, in step 8, processing for estimating the moving speed of the object is performed as follows based on the temporal change of the position candidates.
The existence range estimation unit 7 has a function of storing position candidates detected in the past. As shown in FIG. 9, the existence range estimation unit 7 reads position candidates at time t ₀ , t ₁ , t ₂ , respectively, one position candidate at time t ₀ , one position candidate at time t ₁ , in the one position candidates in time t _2, the predetermined relationship (e.g., at a predetermined speed range, the relationship which is moving in a certain direction) determines whether is satisfied. When the predetermined relationship is established, the above three position candidates are determined to be position candidates detected by moving one object at times t ₀ , t ₁ , and t ₂ . Then, the moving distance of the object from the time t ₀ to t _2, by dividing by the time difference from time t ₀ to t _2, to estimate the size of the object moving speed of. Also, the moving direction of the object is estimated.

Returning to FIG. 5, in step 9, a light emission process for causing the light emitting unit 9 to emit light is performed. Specifically, it is determined on which link the position candidates narrowed down in step 6 are.
And among the several LED lamps which comprise the light emission part 9, the thing corresponding to the link in which a position candidate exists is light-emitted. For example, when the position candidate is on the link L ₃₆ (link formed by the communication device BS6 and the communication device BS3), among the plurality of LED lamps constituting the light emitting unit 9, the one near the communication device BS3 is caused to emit light. Further, the light emission amount of the LED lamp included in the communication device BS6 changes according to the positional relationship between the position candidate and the communication device BS6. Specifically, the closer the position candidate is to the communication device BS6, the greater the light emission amount of the LED lamp provided in the communication device BS6.

  In step 10, the position candidates narrowed down in step 6, the size of the object estimated in step 7, the size of the speed of object estimated in step 8, and the moving direction of the object are sent to the transmission unit 3. Output to the outside. Note that, for example, a vehicle traveling on the road 103 can receive the output information and use it for alarm prevention and intervention control from the relative distance from the own vehicle or the like to help prevent accidents.

3. Effects produced by the object detection system 1 (1) The object detection system 1 can detect an object (such as a vehicle) on a road.
(2) The object detection system 1 consumes less power than a conventional system using a laser radar or the like, can simplify individual devices, and can be easily installed by driving a solar cell or the like.

(3) The object detection system 1 can make the detection range wide-angle and improve the detection position accuracy as compared with the conventional system using a laser radar or the like.
(4) The object detection system 1 is less susceptible to the weather than a conventional system using a laser radar or the like.

(5) The object detection system 1 is less susceptible to privacy issues than conventional systems that use cameras.
(6) The object detection system 1 can estimate the size of the object and the speed of the object.

  (7) Each communication device in the object detection system 1 can transmit an object position candidate detected by itself to another communication device. Therefore, each communication device can detect an object more accurately.

  (8) The object detection system 1 includes a light emitting unit 9 that emits light when an object is detected. Therefore, the user can easily know the presence of the object by the light emission of the light emitting unit 9. Moreover, the light emission part 9 light-emits the thing corresponding to the link in which a position candidate exists among several LED lamps. Therefore, the user can know the direction of the object depending on which LED lamp emits light. Further, the closer the object position candidate is to each communication device, the greater the light emission amount of the LED lamp provided in the light emitting unit 9. Therefore, the user can know the distance from the communication device to the object from the light emission amount of the LED lamp.

(9) In the object detection system 1, since each communication device is installed on the road side, an object (for example, a vehicle) existing on the road can be easily detected.
<Second Embodiment>
1. Configuration of Object Detection System 1 The configuration of the object detection system 1 in the present embodiment is basically the same as that in the first embodiment, but is partially different. Below, it demonstrates centering around difference. As shown in FIG. 10, the object detection system 1 includes a plurality of communication devices BS1, BS2, BS3, BS4, BS5, BS6, BS7, BS8 as in the first embodiment.

  However, the communication devices BS5, BS6, BS7, BS8 outside the intersection 106 between the road 103 and the road 105 do not include the light emitting unit 9 as shown in FIG. On the other hand, the communication devices BS1, BS2, BS3, and BS4 in the intersection 106 are provided with the light emitting unit 9 as in the communication device in the first embodiment.

2. Processing executed by the object detection system 1 The processing executed by the processing executed by the object detection system 1 in the present embodiment is basically the same as that of the first embodiment.

However, since the communication devices BS5, BS6, BS7, BS8 do not include the light emitting unit 9, the issuing process (step 9 in FIG. 5) is not executed. Further, the communication devices BS1, BS2, BS3, and BS4 detect position candidates on the road 103 toward the intersection 106 (position candidates detected on the link between the communication devices BS3, BS4, BS5, BS6, BS7, and BS8). In this case, light is emitted using the light emitting unit 9 in the light emission process. The light emission amount of the light emitting unit 9 at that time becomes stronger as the position candidate on the road 103 is closer to the intersection 106.
Note that the communication devices BS5, BS6, BS7, and BS8 may be installed in each direction such as on the road 105. In that case, since the vehicle 101 on the road 105 side detects itself, BS1, BS2, BS3, and BS4 emit light, so that it cannot be distinguished from the object detection result on the road 103. Therefore, when the communication device BS is installed in each route, it is desirable that only the LED in the direction orthogonal to the road where the detected object is present emit light.

3. Effects exhibited by the object detection system 1 (1) The object detection system 1 of the present embodiment can exhibit substantially the same effects as those of the first embodiment.

(2) According to the object detection system 1 of the present embodiment, a vehicle or a pedestrian on the road 105 is on the road 103 by looking at the light emitted from the communication devices BS1, BS2, BS3, BS4 in the intersection 106. The existence of the object and the distance from the intersection 106 to the object can be known. In particular, when the communication device BS is installed in each route, it is possible to know the presence of an object on the orthogonal road with poor visibility by using only the LED on the orthogonal side to help prevent accidents. be able to.
<Third Embodiment>
1. Configuration of Object Detection System 1 The configuration of the object detection system 1 in the present embodiment is basically the same as that in the first embodiment, but is partially different. Below, it demonstrates centering around difference. In this embodiment, as shown in FIG. 12, a plurality of communication devices BS1, BS2, BS3, BS4, BS5, and BS6 are vehicle-mounted devices mounted on vehicles 201, 202, 203, 204, 205, and 206, respectively. is there.

  In the present embodiment, the radio wave transmitted by each communication device using the transmission unit 3 includes, in addition to the BSID and position candidate information, position information of the communication device that is the radio wave transmission source at that time. . Note that the communication device can acquire the position information of the communication device by a known method such as GPS.

2. Processing executed by the object detection system 1 The processing executed by the processing executed by the object detection system 1 in the present embodiment is basically the same as that of the first embodiment.

  However, in the present embodiment, the position of each communication device varies as the vehicle on which they are mounted moves. For this reason, in the process of detecting position candidates (step 3 in FIG. 5), when position candidates on a link are detected, the position information of the two communication devices constituting the link is referred to. Based on the position information of the two communication devices (position information at both ends of the link) and the relative coordinates of the position candidates on the link, the position candidate coordinates (absolute coordinates) are calculated. Each communication device can acquire its own location information by a known method such as GPS. Further, the position information of the communication device on the other end side constituting the link can be extracted from the radio wave transmitted from the communication device.

3. Effects exhibited by the object detection system 1 (1) The object detection system 1 of the present embodiment can exhibit substantially the same effects as those of the first embodiment.

(2) The object detection system 1 of this embodiment can detect a motorcycle or a bicycle that passes between vehicles.
<Fourth Embodiment>
1. Configuration of Object Detection System 1 The object detection system 1 according to the present embodiment has the same configuration as that of the first embodiment.

2. Processing executed by the object detection system 1 The processing executed by the processing executed by the object detection system 1 in the present embodiment is basically the same as that of the first embodiment.

  However, when each communication device detects a position candidate on any of the links, it increases the output of the radio wave transmitted by the transmission unit 3 and widens the range in which the radio wave reaches. For example, in FIG. 13, the radio wave transmitted by the communication device BS6 normally reaches the communication devices BS3, BS4, BS5, BS7, BS8 (in a state where no position candidate is detected on any link), but BS1, BS2 Will not reach. When a position candidate is detected on any of the links, the radio wave transmitted by the communication device BS6 reaches the communication devices BS1 and BS2.

3. Effects exhibited by the object detection system 1 (1) The object detection system 1 of the present embodiment can exhibit substantially the same effects as those of the first embodiment.

(2) In the object detection system 1 of the present embodiment, when a position candidate is detected by any link, a link is also formed with a communication device farther away. As a result, a finer mesh is formed by the set of links, so that the object detection accuracy is improved.
<Fifth Embodiment>
1. Configuration of Object Detection System 1 The object detection system 1 according to the present embodiment includes a plurality of communication devices BS1, BS2, BS3, BS4, BS5, and BS6 as shown in FIG. The communication device BS1 is installed at the center of an intersection 106 where the road 103 and the road 105 intersect. The communication devices BS2, BS3, BS4, BS5, and BS6 are arranged outside the intersection 106 and distributed on the road 103.

  As shown in FIG. 15, the communication device BS1 includes a receiving unit 5, an existence range estimating unit 7, a light emitting unit 9, and a directional antenna 11. That is, the communication device BS1 has a configuration in which the transmission unit 3 is excluded from the communication device in the first embodiment. Therefore, the communication device BS1 can receive radio waves, but cannot transmit radio waves. The communication device BS1 has the same functions as the communication device in the first embodiment except for the function of transmitting radio waves.

  As shown in FIG. 16, the communication devices BS2, BS3, BS4, BS5, and BS6 include a transmission unit 3 and a directional antenna 11, and periodically transmit radio waves with a certain strength. The transmitted radio wave includes BSID, which is an identification code of the communication device that transmits the radio wave, as information.

The communication device BS1 forms links L ₁₂ , L ₁₃ , L ₁₄ , L ₁₅ , L ₁₆ with the communication devices BS2, BS3, BS4, BS5, BS6, respectively. Each link transmits and receives unidirectional radio waves. For example, the link _{L 12,} the communication device BS2 receives radio wave communication device BS1 which transmitted.

2. Processing Performed by Object Detection System 1 In the present embodiment, the communication device BS1 performs basically the same processing as each communication device in the first embodiment. However, the communication device BS1 does not perform the process of transmitting radio waves (Step 4 in FIG. 5). Further, since the position candidates are not included in the radio waves transmitted by the communication devices BS2, BS3, BS4, BS5, and BS6, the process of step 5 in FIG. 5 is not performed.

Further, the communication devices BS2, BS3, BS4, BS5, BS6 do not perform the processing shown in the flowchart of FIG.
3. Effects exhibited by the object detection system 1 (1) The object detection system 1 of the present embodiment can exhibit substantially the same effects as those of the first embodiment.

(2) According to the object detection system 1 of the present embodiment, the system configuration can be further simplified.
<Other embodiments>
(1) In the first to fourth embodiments, as shown in FIG. 17, the radio wave transmitted by the communication device includes the BSID of the source communication device and the power (intensity) of the radio wave received from another communication device. ). FIG. 17 shows the radio wave transmitted by the communication device BS6, the BSID of the communication device BS6, the power of the radio wave received by the communication device BS6 from the communication device BS7, the power of the radio wave received by the communication device BS6 from the communication device BS5,・ ・ Is included as information.

  In this case, the communication device that has received the radio wave can calculate the fluctuation amount ΔR in a certain link from the power of the radio wave included as information in the radio wave. Then, the variation amount ΔR can be applied to a position candidate table (see FIG. 6), and position candidates on the link can be calculated.

Each communication device holds the standard strength R _nm for links other than the link to which the communication device belongs, and also for the links other than the link to which the communication device belongs, the amount of variation ΔR and the position candidate in the position candidate table. Are associated with each other.

  (2) In the first to fifth embodiments, each communication device may calculate a received packet lost rate or a transfer function of a propagation path for each link. A position candidate can be detected by applying the received packet lost ratio or transfer function to a table that defines the relationship between the received packet lost ratio or transfer function and the position candidate.

  (3) In the first to fifth embodiments, the light emitting unit 9 may be a single LED lamp. In this case, for example, when a position candidate is detected on any link, or when a position candidate is detected on a predetermined link, the LED lamp can be caused to emit light.

(4) In the first to fifth embodiments, any one or more of steps 6, 7, and 8 in FIG. 5 may be omitted.
(5) In the first to fifth embodiments, one of steps 9 and 10 in FIG. 5 may be omitted.

  (6) A part or all of the configurations in the first to fifth embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 ... Object detection system, 3 ... Transmission part, 5 ... Reception part, 7 ... Existence range estimation part, 9 ... Light emission part, 9A, 9B, 9C ... LED lamp, 11 ... Directional antenna, 13 ... Case, 101 ... Vehicle, 103, 105 ... road, 103A, 103B ... roadside, 106 ... intersection, 107, 109 ... object, 201, 202, 203, 204, 205, 206 ... vehicle, BS1, BS2, BS3, BS4, BS5, BS6, BS7, BS8 ... communication device

Claims (9)

A plurality of communication devices capable of at least one of radio wave transmission and reception;
An object detection system including a plurality of links including the communication device that transmits the radio wave and the communication device that receives the radio wave,
The communication device that receives the radio wave includes a position detection unit that detects a position of an object existing between the links based on a reception state of a radio wave transmitted by the communication device belonging to the same link. Object detection system.   The said communication apparatus which receives the said electromagnetic wave is provided with the magnitude | size estimation means which estimates the magnitude | size of an object based on two or more of the said positions, when two or more of said positions are detected. Object detection system.   The said communication apparatus which receives the said electromagnetic wave is provided with the speed estimation means which estimates the moving speed of an object based on the time-dependent change of the said position detected by the said position detection means. The object detection system described.   The said communication apparatus which receives the said electromagnetic wave is provided with the detection result transmission means which transmits the detection result of the said position detection means to the other said communication apparatus, The any one of Claims 1-3 characterized by the above-mentioned. Object detection system.   The at least part of the communication device that receives the radio wave can also transmit the radio wave, and when the position is detected by the position detection unit, the reach of the radio wave to be transmitted is widened. Item 5. The object detection system according to any one of Items 1 to 4.   The object detection system according to claim 1, wherein at least a part of the communication device that receives the radio wave includes a light emitting unit that emits light based on a detection result of the position detection unit. .   The object detection system according to claim 6, wherein the light emission unit changes a light emission amount according to a positional relationship between the position of the object detected by the position detection unit and a predetermined reference position.   The object detection system according to claim 1, wherein at least a part of the communication device is installed on a road side.   The object detection system according to claim 1, wherein at least a part of the communication device is an in-vehicle device.

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