JP6716956B2 - Radio wave sensor and detection program - Google Patents

Description

The present invention relates to a radio wave sensor and a detection program, and more particularly to a radio wave sensor and a detection program that detect an object using radio waves.

In recent years, radio wave sensors have been developed to support safe driving. For example, Japanese Unexamined Patent Application Publication No. 2012-247215 (Patent Document 1) discloses an object identification device that is mounted on a vehicle and that identifies the type of an object existing around the vehicle. That is, the object identification device provides information on the reflection intensity and the distance to the object around the own vehicle, which is obtained by irradiating the sound wave or the electromagnetic wave around the own vehicle and detecting the reflected wave of the sound wave or the electromagnetic wave. The included object information and the height information of the object obtained by the image processing are acquired. The object identification device corrects the reflection intensity according to the height of the object and the distance to the object. Then, the object identification device identifies the type of the object according to the corrected reflection intensity.

Further, Patent Document 2 (JP 2013-257210 A) discloses the following technique. That is, the pedestrian detector is installed above a sidewalk or a roadway, and the boundary between the sidewalk and the roadway is used as a detection area, and the detection area is irradiated with an electromagnetic wave of a predetermined frequency to detect the frequency of the reflected wave. Doppler radar, a calculation unit that determines the presence or absence of a pedestrian passing through the detection area from the sidewalk side toward the roadway side based on the frequency of the reflected wave detected by the Doppler radar, and the determination of the calculation unit Output means for outputting a pedestrian detection signal.

JP 2012-247215 A JP, 2013-257210, A

Koji Yoichi, 2 others, “Application of expanding millimeter wave technology”, [online], [September 20, 2015 search], Internet <URL:http://www. spc. co. jp/spc/pdf/giho21_09. pdf〉 Inaba Noriyuki, Kirimoto Tetsuro, "Vehicle Millimeter-wave Radar", Automotive Technology, February 2010, Volume 64, No. 2, p. 74-79 Nobuyoshi Kikuma, "Adaptive Signal Processing by Array Antenna", First Edition, Science and Technology Publishing Co., Ltd., November 1998, p. 181, p. 194

However, in the object identification device described in Patent Document 1, the type of the object is identified using the sound wave or electromagnetic wave irradiation processing and detection processing, and the image processing, so the configuration of the device is complicated and costly. There is a problem.

The present invention has been made to solve the above problems, and an object thereof is to provide a radio wave sensor and a detection program capable of more accurately detecting an object in a target area with a simple and low-cost configuration. It is to be.

(1) In order to solve the above problems, a radio wave sensor according to an aspect of the present invention includes a measuring unit that can measure the position of an object in a target area regularly or irregularly, and the position of the object estimated in the past. Based on the above, the positional relationship between the estimation unit that estimates the position of the object this time and the position of the object measured by the measurement unit and the position of the object estimated by the estimation unit satisfies the first predetermined condition. And a detection unit that determines that the object is a detection target when the number of times of satisfying is a predetermined number of times or more within a predetermined time.

(5) In order to solve the above-mentioned problems, a radio wave sensor according to another aspect of the present invention is a radio wave generated using a modulation method of FM-CW (Frequency Modulated-Continuous Wave) method and a modulation of a two-frequency CW method. The position of an object in the target area is regularly or non-determined based on a transmitter that can transmit a radio wave generated using the method to the target area, a receiver that receives the radio wave, and the radio wave received by the receiver. When a measuring unit that can measure periodically and a stationary object that is a stopped object in the target area are measured by the measuring unit using the FM-CW method, the two-frequency CW method by the measuring unit is used. And a detection unit that determines whether or not the moving object is a detection target object based on a measurement result of the moving object that is an object in the target area different from the stationary object.

(6) In order to solve the above problems, a detection program according to an aspect of the present invention is a detection program used in a radio wave sensor, and a computer measures the position of an object in a target area regularly or irregularly. A possible measurement unit, an estimation unit that estimates the position of the object this time based on the position of the object estimated in the past, the position of the object measured by the measurement unit, and the position estimated by the estimation unit A program for causing a detection unit to determine that the object is a detection target when the number of times the positional relationship with the position of the object satisfies the first predetermined condition is a predetermined number of times or more within a predetermined time period. Is.

(7) In order to solve the above problems, a detection program according to another aspect of the present invention is a radio wave generated using the FM-CW modulation method and a radio wave generated using the two-frequency CW modulation method. Is a detection program that can be transmitted to a target area and is used in a radio wave sensor that receives radio waves, and enables a computer to periodically or irregularly measure the position of an object in the target area based on the received radio wave. Measurement unit and in the target area, when a stationary object that is a stopped object is measured by the measurement unit using the FM-CW method, the stop using the two-frequency CW method by the measurement unit And a detection unit that determines whether or not the moving object is a detection target object based on a measurement result of a moving object that is an object in the target area different from the object.

The present invention can be realized not only as a radio wave sensor including such a characteristic processing unit but also as a method in which such characteristic processing is used as a step, or a part or all of the radio wave sensor. It can be realized as a semiconductor integrated circuit or as a system including a radio wave sensor.

According to the present invention, it is possible to more accurately detect an object in an object area with a simple and low-cost configuration.

FIG. 1 is a diagram showing a configuration of a safe driving support system according to an embodiment of the present invention. FIG. 2 is a diagram showing a state in which the safe driving support system according to the exemplary embodiment of the present invention is installed at an intersection as seen obliquely from above. FIG. 3 is a diagram showing the configuration of the radio wave sensor in the safe driving support system according to the embodiment of the present invention. FIG. 4 is a diagram showing an example of temporal changes in the frequency of the radio wave transmitted and received by the radio wave sensor in the safe driving assistance system according to the embodiment of the present invention. FIG. 5 is a diagram showing an example of an arrangement of the transmitting antennas and the receiving antennas according to the embodiment of the present invention when viewed from above. FIG. 6 is a diagram showing a configuration of a signal processing unit in the radio wave sensor according to the embodiment of the present invention. FIG. 7 is a diagram showing an example of a measurement result table showing detection results of peaks by the measuring unit in the radio wave sensor according to the embodiment of the present invention. FIG. 8 is a diagram showing an example of a tracking result table showing a result of tracking an object by the calculation unit in the radio wave sensor according to the embodiment of the present invention. FIG. 9 is a diagram showing an example of the transition route of the tracking state set in the data aggregate by the arithmetic unit in the radio wave sensor according to the embodiment of the present invention. FIG. 10 is a diagram showing an example of a time-series change of the input value and the output value of each process performed in the arithmetic unit according to the embodiment of the present invention. FIG. 11 is a diagram showing an example of a processing result history table updated by the calculation unit in the radio wave sensor according to the embodiment of the present invention. FIG. 12 is a diagram showing an example of a stationary object list updated by the calculation unit in the radio wave sensor according to the embodiment of the present invention. FIG. 13 is a diagram showing an example of a transition route of the detection state set by the detection unit in the radio wave sensor according to the embodiment of the present invention. FIG. 14 is a flowchart that defines an operation procedure when the radio wave sensor according to the embodiment of the present invention detects an object in a unit sequence. FIG. 15 is a flowchart defining an operation procedure when the radio wave sensor according to the embodiment of the present invention performs a pedestrian candidate state process. FIG. 16 is a flowchart defining an operation procedure when the radio wave sensor according to the embodiment of the present invention performs a pedestrian state process. FIG. 17 is a flowchart defining an operation procedure when the radio wave sensor according to the embodiment of the present invention performs the detection determination process.

First, the contents of the embodiments of the present invention will be listed and described.

(1) The radio wave sensor according to the embodiment of the present invention includes a measuring unit capable of regularly or irregularly measuring the position of an object in a target area, and the object of this time based on the position of the object estimated in the past. The number of times that the positional relationship between the position of the object estimated by the measuring unit and the position of the object estimated by the estimating unit satisfies the first predetermined condition within a predetermined time. In the case of the predetermined number of times or more, a detection unit that determines that the object is a detection target object is provided.

With such a configuration, the object can be detected without performing image processing, so that the radio wave sensor can have a low cost and a simple configuration. Therefore, the object in the target area can be detected more accurately with a simple and low-cost configuration. Further, in this way, the position of the object in the target area is repeatedly measured, and for example, when the measurement position is frequently present in the vicinity of the estimated position, the object is determined to be the detection target. Even if the measurement position does not exist, it is possible to prevent the object from being immediately determined as not the detection target object. As a result, the strength of the radio wave from the detection target received by the radio sensor is weak, and the vehicle passes between the radio sensor and the detection target, so the position of the detection target must be measured. Even when it is difficult to detect the object, the object to be detected can be detected stably.

(2) Preferably, the detection unit, when the number of times the positional relationship satisfies the first predetermined condition is smaller than a predetermined number of times within a predetermined time, or after determining that the object is a detection target, When the number of times the positional relationship satisfies the second predetermined condition is smaller than the predetermined number of times within the predetermined time, it is determined that the object is not the detection target object.

In this way, after determining that the object is the detection target, even if there is no measurement position near the estimated position, for example, it is not immediately determined that the object is not the detection target. If the measurement position in the vicinity is low in frequency, it is possible to mistakenly determine that the object is not the detection target even though the object is the detection target, by the configuration that determines that the object is not the detection target. It can be reduced. Further, for example, even if there is a measurement position in the vicinity of the estimated position, without determining immediately that the object is a detection target, if the frequency of the measurement position in the vicinity of the estimated position is low, The configuration in which it is determined that the object is not the detection target can reduce the possibility of erroneously determining that the object is the detection target even though the object is not the detection target.

(3) Preferably, the estimation unit estimates the position of the object using a time-series filter that uses the position, speed, and moving direction of the object as variables, and the initial value of the variable is determined by the measurement unit. It is a value corresponding to the measured position of the object.

In this way, the position of the object can be estimated more accurately by the configuration using the time series filter that uses the initial value according to the position of the object as a variable.

(4) Preferably, the radio wave sensor is further capable of transmitting a radio wave generated using an FM-CW modulation method and a radio wave generated using a two-frequency CW modulation method to the target area. And a receiving unit that receives radio waves, the measuring unit is capable of measuring the position of the object using the FM-CW method based on the radio waves received by the receiving unit, and the detecting unit. Is the two-frequency CW method by the measuring unit during a period from when the measuring unit measures the new object by using the FM-CW method until it is determined that the new object is a detection target. It is determined whether or not the object is a detection target object based on the measurement result of the object using.

With such a configuration, an undetermined period from when a new object is measured using the FM-CW method until it is determined that the object is a detection target is supplemented by determination using the two-frequency CW method. Therefore, it is possible to realize detection without omission of determination.

(5) The radio wave sensor according to the embodiment of the present invention generates a radio wave generated using a modulation method of FM-CW (Frequency Modulated-Continuous Wave) method and a radio wave generated using a modulation method of 2 frequency CW method. A transmitting unit capable of transmitting to the target area, a receiving unit for receiving radio waves, and a measuring unit capable of regularly or irregularly measuring the position of an object in the target area based on the radio waves received by the receiving unit. In the target area, when a stationary object that is a stopped object is measured by the measuring unit using the FM-CW method, the measuring object uses the dual-frequency CW method and is different from the stationary object. A detection unit that determines whether or not the moving object is a detection target object based on a measurement result of the moving object that is an object in the target area.

With such a configuration, the object can be detected without performing image processing, so that the radio wave sensor can have a low cost and a simple configuration. Therefore, the object in the target area can be detected more accurately with a simple and low-cost configuration. In addition, in this way, it is possible to detect a stopped object such as a stopped vehicle and a utility pole, but when the stopped object exists in the target area, it is difficult to detect a detection target object in the vicinity of the stopped object. When a stationary object is measured by the FM-CW method, which makes it difficult to detect an object in a region, it is difficult to detect the stationary object, while detecting a moving object moving near the stationary object. The weaknesses of these methods can be complemented by a configuration that determines whether or not a moving object is a detection target by using a dual-frequency CW method that can be performed. As a result of being present at a position beyond the stop line, it is possible to correctly determine whether or not an object moving in the detection difficult area is a pedestrian even when a detection difficult area occurs near the vehicle. ..

(6) A detection program according to an embodiment of the present invention is a detection program used in a radio wave sensor, and includes a computer, a measuring unit capable of measuring the position of an object in a target area regularly or irregularly, An estimation unit that estimates the position of the object at this time based on the position of the object estimated to, a positional relationship between the position of the object measured by the measurement unit and the position of the object estimated by the estimation unit. Is a program for causing the detection unit to determine that the object is a detection target when the number of times satisfying the first predetermined condition is a predetermined number of times or more within a predetermined time.

With such a configuration, the object can be detected without performing image processing, so that the radio wave sensor can have a low cost and a simple configuration. Therefore, the object in the target area can be detected more accurately with a simple and low-cost configuration. Further, in this way, the position of the object in the target area is repeatedly measured, and for example, when the measurement position is frequently present in the vicinity of the estimated position, the object is determined to be the detection target. Even if the measurement position does not exist, it is possible to prevent the object from being immediately determined as not the detection target object. As a result, the strength of the radio wave from the detection target received by the radio sensor is weak, and the vehicle passes between the radio sensor and the detection target, so the position of the detection target must be measured. Even when it is difficult to detect the object, the object to be detected can be detected stably.

(7) The detection program according to the embodiment of the present invention can transmit a radio wave generated using the FM-CW modulation method and a radio wave generated using the two-frequency CW modulation method to the target area. A detection program used in a radio wave sensor for receiving a radio wave, comprising: a measuring unit capable of measuring the position of an object in the target area on a regular or irregular basis by a computer based on the received radio wave; In, when a stationary object which is a stopped object is measured by the measuring unit using the FM-CW method, an object in the target area different from the stationary object using the dual frequency CW method by the measuring unit And a detection unit that determines whether or not the moving object is a detection target based on the measurement result of the moving object.

With such a configuration, the object can be detected without performing image processing, so that the radio wave sensor can have a low cost and a simple configuration. Therefore, the object in the target area can be detected more accurately with a simple and low-cost configuration. In addition, in this way, it is possible to detect a stopped object such as a stopped vehicle and a utility pole, but when the stopped object exists in the target area, it is difficult to detect a detection target object in the vicinity of the stopped object. When a stationary object is measured by the FM-CW method, which makes it difficult to detect an object in a region, it is difficult to detect the stationary object, while detecting a moving object moving near the stationary object. The weaknesses of these methods can be complemented by a configuration that determines whether or not a moving object is a detection target by using a dual-frequency CW method that can be performed. As a result of being present at a position beyond the stop line, it is possible to correctly determine whether or not an object moving in the detection difficult area is a pedestrian even when a detection difficult area occurs near the vehicle. ..

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the same or corresponding parts in the drawings are designated by the same reference numerals and description thereof will not be repeated. Further, at least a part of the embodiments described below may be arbitrarily combined.

[Configuration and basic operation]
FIG. 1 is a diagram showing a configuration of a safe driving support system according to an embodiment of the present invention. FIG. 2 is a diagram showing a state in which the safe driving support system according to the exemplary embodiment of the present invention is installed at an intersection as seen obliquely from above.

1 and 2, the safe driving support system 301 includes a radio wave sensor 101, a relay device 141, a signal control device 151, a wireless transmission device 152, an antenna 153, and a pedestrian signal light device 161. Equipped with. The signal control device 151 and the pedestrian signal light device 161 in the safe driving support system 301 constitute a traffic signal and are installed, for example, near the intersection CS1.

[About the intersection]
For example, as shown in FIG. 2, a pedestrian crossing PC1 is provided near the intersection CS1. Here, the road provided with the pedestrian crossing PC1 is defined as the target road Rd1. The target road Rd1 forms an intersection CS1. A road that intersects the target road Rd1 at the intersection CS1 is defined as an intersection road Rd2.

That is, the intersection of the target road Rd1 and the intersection road Rd2 is the intersection CS1. In other words, the intersection CS1 overlaps the target road Rd1 and also overlaps the intersection road Rd2. It should be noted that more roads may intersect at the intersection CS1.

The target road Rd1 includes an outflow road Rde in which an unillustrated automobile Tgt1 flowing out from the intersection CS1 travels, and an inflow road Rdi in which the automobile Tgt1 inflowing into the intersection CS1 travels. A lane TrL is provided between the outflow road Rde and the inflow road Rdi.

A sidewalk Pv1 is provided at an end on the opposite side of the inflow road Rdi with respect to the outflow road Rde so as to extend along the target road Rd1. The sidewalk Pv1 extends along the arc-shaped corner cut CCe near the intersection CS1 to change the extension direction from the direction along the target road Rd1 to the direction along the intersection road Rd2.

A sidewalk Pv2 is provided at the end opposite to the outflow road Rde with respect to the inflow road Rdi so as to extend along the target road Rd1. The sidewalk Pv2 changes the extension direction from the direction along the target road Rd1 to the direction along the intersection road Rd2 by extending along the arcuate corner cut CCi in the vicinity of the intersection CS1.

The target area A1 is at least a part of the irradiation range of the radio wave transmitted from the radio wave sensor 101, and is an area including, for example, the entire crosswalk PC1.

In the target area A1, the sensor installer sets four sub areas SAis, SAes, SAer, and SAir, for example. The number of sub-areas is not limited to four, but may be two, three, or five or more.

The sub-area SAis has, for example, a quadrangular shape and includes a part of the sidewalk Pv2 that is adjacent to the pedestrian crossing PC1. The sub area SAis is, for example, a waiting area for the pedestrian Tgt2.

The sub-area SAes has, for example, a quadrangular shape, and includes a part of the sidewalk Pv1 that is adjacent to the pedestrian crossing PC1. Sub-area SAes is, for example, a waiting area for pedestrian Tgt2.

The sub-area SAer has, for example, a quadrangular shape, and includes at least a part of an overlapping area of a pedestrian crossing PC1 and a portion of a road on which a vehicle flowing out from the intersection CS1 passes. In this example, the sub area SAer includes an area where the crosswalk PC1 and the outflow road Rde overlap. The sub-area SAer is an area through which the pedestrian Tgt2 passes along the pedestrian crossing PC1 when the pedestrian signal light device 161 lights the “recommendation” and is not shown in the figure, which is turned right or left from the intersection road Rd2. This is an area where the automobile Tgt1 passes along the target road Rd1. Hereinafter, the sub area SAer is also referred to as an outflow area.

The sub-area SAir has, for example, a quadrangular shape, and includes at least a part of an overlapping area of a pedestrian crossing PC1 and a road portion where a vehicle flowing into the intersection CS1 passes. In this example, the sub-area SAir includes, for example, an area where the crosswalk PC1 and the inflow road Rdi overlap. The sub-area SAir is an area where the pedestrian Tgt2 passes along the pedestrian crossing PC1 when the pedestrian signal light device 161 lights "Recommendation". Hereinafter, the sub-area SAir will also be referred to as an inflow area.

The radio wave sensor 101 can detect an object in the target area A1 as a detection target. More specifically, the radio wave sensor 101 detects a pedestrian Tgt2 crossing a road in the target area A1 using the pedestrian crossing PC1 as a detection target. Here, the pedestrian Tgt2 is not limited to a walking person, and includes a bicycle and the like. In addition to the pedestrian Tgt2, the detection target may include an automobile Tgt1 that travels along the target road Rd1 and passes through the pedestrian crossing PC1.

[Radio sensor installation position]
The radio wave sensor 101 is installed, for example, near the target road Rd1. Specifically, the radio wave sensor 101 is fixed to a pillar PW installed on the side opposite to the target road Rd1 with respect to the sidewalk Pv1. More specifically, the radio wave sensor 101 is provided on an extension line of the pedestrian crossing PC1 toward the sidewalk Pv1.

The relay device 141 is fixed to the support PW. Although not shown in FIG. 2, the radio wave sensor 101 and the relay device 141 are connected by, for example, a signal line. The relay device 141 performs a relay process of transmitting the information received from the radio wave sensor 101 to the signal control device 151.

The signal control device 151 and the wireless transmission device 152 are fixed to a pillar PV installed on the opposite side of the target road Rd1 with respect to the sidewalk Pv2. The antenna 153 is fixed to the top of the pillar PV.

The two pedestrian signal light devices 161 are fixed to the columns PW and PV, respectively. Although not shown in FIG. 2, the signal control device 151, the wireless transmission device 152, the relay device 141, and the two pedestrian signal light devices 161 are connected by signal lines. Although not shown in FIG. 2, the wireless transmission device 152 and the antenna 153 are connected by a signal line.

The radio wave sensor 101 transmits a radio wave to the target area A1. The object located in the target area A1 reflects the radio wave transmitted from the radio wave sensor 101. The radio wave sensor 101 receives a radio wave reflected by an object.

The radio wave sensor 101 detects the pedestrian Tgt2 on the pedestrian crossing PC1 based on the received radio wave, and transmits the detection result to the signal control device 151 via the relay device 141.

Under the control of the signal control device 151, the pedestrian signal light device 161 lights up and displays “recommendation” or “remarkable” for the pedestrian Tgt2 crossing the pedestrian crossing PC1.

For example, the signal control device 151 extends the remaining time when the detection result indicates that the pedestrian Tgt2 is detected at the pedestrian crossing PC1 in the case where the remaining time for lighting the “recommendation” in the pedestrian signal light device 161 is small. I do. Note that the signal control device 151 may, for example, notify the pedestrian Tgt2 by voice that the remaining time for lighting “Recommendation” is short.

Further, the signal control device 151 is dangerous when the detection result indicates that the pedestrian Tgt2 has been detected at the pedestrian crossing PC1 when, for example, “Tomare” is lit on the pedestrian signal light device 161. Is audibly warned to the pedestrian Tgt2.

Further, the signal control device 151 provides a service to the automobile Tgt1 based on the detection result received from the radio wave sensor 101.

Specifically, for example, when the detection result indicates that the pedestrian Tgt2 exists at the pedestrian crossing PC1, the signal control device 151 outputs pedestrian warning information indicating that the pedestrian Tgt2 at the pedestrian crossing PC1 should be noted. The pedestrian warning information that has been created is transmitted to the wireless transmission device 152.

For example, when the wireless transmission device 152 receives the pedestrian warning information from the signal control device 151, the wireless transmission device 152 generates a radio wave including the received pedestrian warning information, and transmits the generated radio wave via the antenna 153, so that the area around the intersection CS1. Pedestrian warning information is reported to the automobile Tgt1 located at.

For example, a vehicle Tgt1 (not shown) turning right or left from the crossroad Rd2 and trying to pass the pedestrian crossing PC1 receives the radio wave transmitted from the wireless transmission device 152, and acquires the pedestrian warning information included in the received radio wave. Then, based on the acquired pedestrian warning information, the driver of the vehicle Tgt1 is notified that the crossing target on the pedestrian crossing PC1 should be noted.

[Radio sensor configuration]
FIG. 3 is a diagram showing the configuration of the radio wave sensor in the safe driving support system according to the embodiment of the present invention.

With reference to FIG. 3, the radio wave sensor 101 includes a transmission unit 1, a reception unit 2, a difference signal generation unit 3, a control unit 4, a signal processing unit 5, and a detection unit 7.

The transmission unit 1 includes a transmission antenna 21, a power amplifier 22, a directional coupler 23, a VCO (Voltage-Controlled Oscillator) 24, a voltage generation unit 25, and a switch 26.

The receiving unit 2 includes receiving antennas 31A, 31B, 31C, 31D and low noise amplifiers 32A, 32B, 32C, 32D. Hereinafter, each of the receiving antennas 31A, 31B, 31C, 31D is also referred to as a receiving antenna 31. Each of the low noise amplifiers 32A, 32B, 32C and 32D is also referred to as a low noise amplifier 32.

The low noise amplifier 32 is provided corresponding to the receiving antenna 31. In FIG. 3, four sets of the receiving antenna 31 and the corresponding low noise amplifier 32 are representatively shown, but two, three, or five or more sets may be provided.

The differential signal generator 3 includes mixers 33A, 33B, 33C and 33D, IF (Intermediate Frequency) amplifiers 34A, 34B, 34C and 34D, low pass filters 35A, 35B, 35C and 35D, and an A/D converter (ADC). 36A, 36B, 36C, 36D.

Hereinafter, each of the mixers 33A, 33B, 33C, 33D is also referred to as a mixer 33. Each of the IF amplifiers 34A, 34B, 34C, 34D is also referred to as an IF amplifier 34. Each of the low pass filters 35A, 35B, 35C and 35D is also referred to as a low pass filter 35. Each of the AD converters 36A, 36B, 36C, and 36D is also referred to as an AD converter 36.

The mixer 33, the IF amplifier 34, the low-pass filter 35, and the A/D converter 36 are provided corresponding to the reception antenna 31. In FIG. 3, four sets of the mixer 33, the IF amplifier 34, the low-pass filter 35, and the A/D converter 36 are shown as representatives, but two, three, or five or more sets may be provided. Good.

The radio wave sensor 101 is described in Non-Patent Document 1 (Koji Yoichi, 2 people, “Expanding application of millimeter wave technology”, [online], [September 20, 2015 search], Internet <URL:http:/// www.spc.co.jp/spc/pdf/giho21_09.pdf>) and Non-Patent Document 2 (Takayuki Inaba, Tetsuro Kirimoto, "In-vehicle millimeter wave radar", Automotive Technology, February 2010, Volume 64, No. 2, P.74-79), which is a radar for detecting an object to be detected using an FM-CW (Frequency Modulated-Continuous Wave) method and a two-frequency CW method.

The transmission unit 1 in the radio wave sensor 101, for example, transmits to the target area A1 a radio wave generated using a modulation method of FM-CW (Frequency Modulated-Continuous Wave) method and a radio wave generated using a modulation method of 2 frequency CW method. Can be sent.

More specifically, the transmitter 1 time-divisionally transmits, for example, an FM-CW (Frequency Modulated-Continuous Wave) modulation radio wave and a two-frequency CW modulation radio wave.

The modulation method of the transmission radio wave is not limited to the FM-CW method and the two-frequency CW method, but may be another modulation method such as a pulse method or a two-frequency ICW (Interrupted CW) method.

When the pulse method or the two-frequency ICW method is used, since the discontinuous wave is used, the distance between the radio wave sensor 101 and the object can be calculated based on the timing when the transmission of radio waves is started or stopped, The influence of multipath can be reduced.

Further, when the two-frequency CW method is used, it is difficult to separately detect two objects that have substantially the same moving speed along the direction toward or away from the radio wave sensor 101. On the other hand, when the two-frequency ICW method is used, the two objects can be detected separately when the distance between the two objects is large.

Hereinafter, the radio waves of frequencies F1 and F2 generated by the transmitter 1 using the dual frequency CW method are also referred to as transmission waves RFt1 and RFt2, respectively. The radio wave generated by the transmitter 1 using the FM-CW method is also referred to as a transmission wave RFt3. Further, each of the transmission waves RFt1, RFt2, and RFt3 is also referred to as a transmission wave RFt.

Upon receiving the measurement start command from the signal control device 151 via the relay device 141, the control unit 4 causes the radio wave sensor 101 of its own to start the detection processing of the detection target according to the received measurement start command.

FIG. 4 is a diagram showing an example of temporal changes in the frequency of the radio wave transmitted and received by the radio wave sensor in the safe driving assistance system according to the embodiment of the present invention.

In FIG. 4, the horizontal axis represents time and the vertical axis represents frequency. The frequency Ft of the radio wave to be transmitted is represented by the solid line, and the frequency Fr of the radio wave to be received is represented by the broken line. In FIG. 4, the delay of the received radio wave with respect to the transmitted radio wave is shown.

With reference to FIG. 4, in the radio wave sensor 101, for example, transmission periods P1 and P2 for transmitting transmission waves RFt1 and RFt2 having frequencies F1 and F2, respectively, which are generated by using the two-frequency CW method, and FM-CW. The transmission period P3 for transmitting the transmission wave RFt3 generated using the method is repeated in this order. Here, for example, a guard period Pg in which the radio wave sensor 101 does not transmit radio waves is provided between the transmission periods P2 and P3 and between the transmission periods P3 and P1. Further, the transmission periods P1 and P2 have the same length, for example. The frequency F2 is smaller than the frequency F1.

Referring to FIGS. 3 and 4, the control unit 4 sets the frequency sweep width Δf and the sweep time Ts, which is the length of the transmission period P3, used in the FM-CW method as initial setting values, and the transmission unit 1 and the signal processing unit 5. Output to.

The control unit 4 repeatedly sets the transmission period P1, the transmission period P2, the guard period Pg, the transmission period P3, and the guard period Pg in this order. Here, the temporally continuous transmission period P1, transmission period P2, guard period Pg, transmission period P3, and guard period Pg are defined as a unit sequence US. The length of the unit sequence US, that is, the measurement period is, for example, τ. The measurement period τ is, for example, 100 milliseconds.

More specifically, the control unit 4 generates the control signal Ss1 and outputs it to the transmission unit 1 and the signal processing unit 5 at the start timing of the transmission period P1. Further, the control unit 4 generates the control signal St1 and outputs the control signal St1 to the transmission unit 1 and the signal processing unit 5 at the end timing of the transmission period P1, that is, the start timing of the transmission period P2.

At the end timing of the transmission period P2, the control unit 4 generates the control signal Se1 and outputs it to the transmission unit 1 and the signal processing unit 5. The control unit 4 also generates the control signals Ss2 and Se2 at the start timing and the end timing of the transmission period P3, and outputs the generated control signals Ss2 and Se2 to the transmission unit 1 and the signal processing unit 5.

The VCO 24 in the transmitter 1 generates a transmission wave RFt having a frequency according to the magnitude of the voltage received from the voltage generator 25.

Upon receiving the control signal Ss1 from the control unit 4, the voltage generation unit 25 generates a voltage of magnitude V1a and outputs it to the VCO 24 until it receives the control signal St1 from the control unit 4. The VCO 24 generates the transmission wave RFt1 in the 24 GHz band having the frequency F1 and outputs the transmission wave RFt1 to the switch 26 while receiving the voltage of the magnitude V1a from the voltage generation unit 25.

Further, when the voltage generator 25 receives the control signal St1 from the controller 4, the voltage generator 25 generates a voltage of magnitude V1b and outputs it to the VCO 24 until it receives the control signal Se1 from the controller 4. The VCO 24 generates the transmission wave RFt2 in the 24 GHz band having the frequency F2 and outputs the transmission wave RFt2 to the switch 26 while receiving the voltage of the magnitude V1b from the voltage generation unit 25.

Further, when receiving the control signal Ss2 from the control unit 4, the voltage generation unit 25 uses the frequency sweep width Δf and the sweep time Ts received from the control unit 4 in advance as initial setting values to output the control signal Se2 from the control unit 4. Until receiving, a voltage whose magnitude increases at a constant rate, that is, an FM modulation voltage is generated and output to the VCO 24.

The VCO 24 generates a transmission wave RFt3 in the 24 GHz band having a frequency sweep width Δf of 180 MHz according to the FM modulation voltage received from the voltage generator 25, and outputs the transmission wave RFt3 to the switch 26.

Switch 26 has a first end connected to VCO 24 and a second end connected to directional coupler 23. Upon receiving the control signal Ss1 or Ss2 from the control unit 4, the switch 26 electrically connects the first end and the second end. When the switch 26 receives the control signal Se1 or Se2 from the control unit 4, the switch 26 electrically insulates the first end and the second end. As a result, the transmission wave RFt output by the VCO 24 is transmitted to the directional coupler 23 in the transmission periods P1, P2 and P3, and is not transmitted to the directional coupler 23 in the guard period Pg.

The directional coupler 23 distributes the transmission wave RFt received from the VCO 24 to the power amplifier 22 and the differential signal generator 3.

The power amplifier 22 amplifies the transmission wave RFt received from the directional coupler 23, and transmits the amplified transmission wave RFt to the target area A1 via the transmission antenna 21.

FIG. 5 is a diagram showing an example of an arrangement of the transmitting antennas and the receiving antennas according to the embodiment of the present invention when viewed from above.

3 and 5, receiving antennas 31A to 31D are located in the vicinity of transmitting antenna 21, for example. More specifically, the receiving antennas 31</b>A to 31</b>D are horizontally arranged along the extending direction of the target road Rd<b>1 at substantially the same height as the transmitting antenna 21, for example. The receiving antennas 31 are arranged, for example, in the order of the receiving antennas 31A to 31D from the side of the intersection CS1 at intervals d.

The receiving antennas 31A to 31D may be arranged at positions distant from the transmitting antenna 21, but are preferably arranged in the vicinity of the transmitting antenna 21 in order to simplify the configuration of the radio wave sensor 101.

Here, the azimuth angle φ indicating the angle at which a reflected wave from an object, for example, a pedestrian Tgt2 is incident on the receiving antenna 31, is a direction in which the receiving antennas 31A to 31D are arranged and the direction X toward the intersection CS1 is φ=90. And φ increases in the clockwise direction when viewed from above the receiving antenna 31. Therefore, the direction Y of φ=0° is the extending direction of the pedestrian crossing PC1.

The radio wave sensor 101 is not limited to the configuration in which the transmitting antenna 21 and the plurality of receiving antennas 31 are separate antennas, and may be configured to use any one of the plurality of receiving antennas 31 as a transmitting antenna. Good.

Referring to FIG. 3, the receiving unit 2 receives a radio wave from the target area A1 or the like. More specifically, as the radio waves received by the receiving unit 2, the radio waves reflected by the detection target and the radio waves reflected by the structures that are objects other than the detection target, such as the guardrail and the pole, and the radio waves are transmitted. It includes radio waves from radio wave transmitters. The receiving antennas 31A to 31D in the receiving unit 2 respectively receive the radio waves from the target area A1 and the like.

The low noise amplifiers 32A to 32D amplify the reception waves RFr1 to RFr4, which are radio waves received by the reception antennas 31A to 31D, and output the amplified reception waves RFr1 to RFr4 to the difference signal generation unit 3.

The difference signal generation unit 3 generates a difference signal having a frequency component that is the difference between the frequency component of the radio wave transmitted by the transmission unit 1 and the frequency component of the radio wave received by the reception unit 2.

More specifically, the mixers 33A to 33D in the difference signal generation unit 3 have difference signals having frequency components of differences between the transmission wave RFt received from the transmission unit 1 and the reception waves RFr1 to RFr4 received from the low noise amplifiers 32A to 32D, respectively. Ba1 to Ba4 are generated. The mixers 33A to 33D output the generated difference signals Ba1 to Ba4 to the IF amplifiers 34A to 34D, respectively.

The IF amplifiers 34A to 34D amplify the differential signals Ba1 to Ba4 received from the mixers 33A to 33D, respectively, and output them to the low pass filters 35A to 35D.

The low-pass filters 35A to 35D attenuate components of a predetermined frequency or higher among the frequency components of the differential signals Ba1 to Ba4 amplified by the IF amplifiers 34A to 34D, respectively.

The A/D converter 36A performs sampling processing of the differential signal Ba1 at a predetermined sampling frequency fsmpl, for example. More specifically, the A/D converter 36A digitally outputs the difference signal Ba1 that is an analog signal that has passed through the low-pass filter 35A by q bits (q is an integer of 2 or more) for each sampling period (1/fsmpl). Of the difference signal Bd1.

Similarly, the A/D converters 36B to 36D perform sampling processing of the differential signals Ba2 to Ba4 at the sampling frequency fsmpl, respectively, and convert the analog differential signals Ba2 to Ba4 into digital differential signals Bd2 to Bd4.

The A/D converters 36A to 36D output the converted difference signals Bd1 to Bd4 to the signal processing unit 5, respectively.

FIG. 6 is a diagram showing a configuration of a signal processing unit in the radio wave sensor according to the embodiment of the present invention.

Referring to FIG. 6, the signal processing unit 5 includes a memory 41, an FFT (Fast Fourier Transform) processing unit 42, a measurement unit 46, and a calculation unit (estimation unit) 45. The measuring unit 46 includes an FMCW processing unit 43 and a 2FCW processing unit 44.

The memory 41 in the signal processing unit 5 stores the differential signals Bd1 to Bd4 received from the A/D converters 36A to 36D, respectively.

The FFT processing unit 42 recognizes the transmission periods P1, P2, P3 (see FIG. 4) based on the control signals Ss1, St1, Se1, Ss2, Se2 received from the control unit 4.

When the storage of the differential signals Bd1 to Bd4 in the transmission period P1 in the memory 41 is completed, the FFT processing unit 42 acquires the differential signals Bd1 to Bd4 stored in the memory 41, and with respect to the acquired differential signals Bd1 to Bd4. FFT processing is performed for each.

More specifically, the FFT processing unit 42 generates the power spectrum FS11 and the phase spectrum PS11 by performing the FFT processing on the difference signal Bd1. Here, the power spectrum FS11 indicates the amplitude of each frequency component included in the differential signal Bd1 accumulated in the transmission period P1. In addition, the phase spectrum PS1 indicates the phase of each frequency component included in the differential signal Bd1 accumulated in the transmission period P1.

Similarly, the FFT processing unit 42 performs FFT processing on the differential signals Bd2, Bd3, Bd4 accumulated in the transmission period P1 to generate power spectra FS12, FS13, FS14, respectively, and at the same time, phase spectra PS12, PS13 and PS14 are generated respectively.

The FFT processing unit 42 outputs the generated power spectra FS11 to FS14 and the phase spectra PS11 to PS14 to the 2FCW processing unit 44.

The FFT processing unit 42 also performs FFT processing on the differential signals Bd1, Bd2, Bd3, Bd4 accumulated in the transmission period P2 in the same manner to generate power spectra FS21, FS22, FS23, FS24, and a phase spectrum. PS21, PS22, PS23 and PS24 are generated respectively.

The FFT processing unit 42 outputs the generated power spectra FS21 to FS24 and the phase spectra PS21 to PS24 to the 2FCW processing unit 44.

The FFT processing unit 42 also performs FFT processing on the differential signals Bd1, Bd2, Bd3, Bd4 accumulated in the transmission period P3 in the same manner to generate power spectra FS31, FS32, FS33, FS34, and a phase spectrum. PS31, PS32, PS33 and PS34 are generated respectively.

The FFT processing unit 42 outputs the generated power spectra FS31 to FS34 and phase spectra PS31 to PS34 to the FMCW processing unit 43.

FIG. 7 is a diagram showing an example of a measurement result table showing detection results of peaks by the measuring unit in the radio wave sensor according to the embodiment of the present invention. In the measurement result table 400 shown in FIG. 7, the measurement position in polar coordinates, the measurement position in rectangular coordinates, and the object identifier corresponding to the peak are listed for each detected peak.

With reference to FIG. 7, the measurement unit 46 can periodically measure the position of the object in the target area A1. Here, “measurable” means that the measurement unit 46 periodically measures the position of the object when the position of the object can be measured, for example, when the object exists in the target area A1. means. When the position of the object cannot be measured, specifically, for example, when the object does not exist in the target area A1 or when the intensity of the reflected wave from the object in the target area A1 is weak, the measuring unit 46 determines the position of the object. Do not measure.

More specifically, the FMCW processing unit 43 and the 2FCW processing unit 44 in the measuring unit 46 determine the position of the object using the FM-CW method and the two-frequency CW method, for example, based on the radio wave received by the receiving unit 2. Each can be measured.

The FMCW processing unit 43 holds, for example, a background spectrum that is a power spectrum in a state where there are no movable objects such as a pedestrian Tgt2 and a car Tgt1 in the target area A1.

Upon receiving the power spectra FS31 to FS34 and the phase spectra PS31 to PS34 from the FFT processing unit 42, the FMCW processing unit 43 performs the following processing.

That is, the FMCW processing unit 43 generates a processed spectrum by subtracting each frequency component of the background spectrum from each frequency component of the power spectrum FS31, for example.

The FMCW processing unit 43 performs peak detection processing on the generated processing spectrum. More specifically, the FMCW processing unit 43 analyzes the processed spectrum and tries to detect a peak having an intensity equal to or higher than the threshold Thfm.

In this example, the FMCW processing unit 43 detects five peaks and adds peak numbers Pn1 to Pn5 to each detected peak.

The FMCW processing unit 43 calculates a measurement position, which is the position of the object corresponding to the detected peak, for each peak.

More specifically, the FMCW processing unit 43 acquires the peak frequency Fb of the detected peak from the processing spectrum, and the acquired frequency Fb and the frequency sweep width Δf and the sweep time Ts received from the control unit 4 are expressed by the following equations. The distance Lp is calculated by substituting in (1).

The FMCW processing unit 43 calculates the distance Lp for each peak. In this example, the FMCW processing unit 43 calculates L1 to L5 as the distances corresponding to the peaks with the peak numbers Pn1 to Pn5, respectively.

Then, the FMCW processing unit 43 calculates the azimuth angles φ1 to φ5 respectively corresponding to the peaks of the peak numbers Pn1 to Pn5 based on the peak frequencies Fb of the peak numbers Pn1 to Pn5 and the phase spectra PS31 to PS34.

More specifically, the FMCW processing unit 43 respectively acquires the phase at the peak frequency Fb of the peak number Pn1 in the phase spectra PS31 to PS34. The FMCW processing unit 43 is a beamformer described in Non-Patent Document 3 (Kikuma Nobuyoshi, “Adaptive Signal Processing by Array Antenna”, First Edition, Science and Technology Publishing Co., Ltd., November 1998, p.181, p.194). The azimuth angle φ1 corresponding to the peak of the peak number Pn1 is calculated based on each acquired phase in accordance with the method, the MUSIC (Multiple Signal Classification) method, the Capon method, and the like.

Similar to the calculation of the azimuth angle φ1, the FMCW processing unit 43 calculates the azimuth angles φ2 to φ5 respectively corresponding to the peaks of the peak numbers Pn2 to Pn5.

The measurement positions of the object respectively corresponding to the peaks of peak numbers Pn1 to Pn5 are the positions indicated by the polar coordinates using the thus calculated distance and azimuth angle.

The FMCW processing unit 43 converts the polar coordinates indicating the measurement position into Cartesian coordinates. Specifically, the calculation unit 45 calculates X1=L1×sin(φ1) and Y1=L1×cos(φ1) to convert the coordinate (L1, φ1) in the polar coordinate system to the coordinate (X1 , Y1).

Similarly, the FMCW processing unit 43 also converts the coordinates (L2, φ2) to (L5, φ5) in the polar coordinate system into the coordinates (X2, Y2) to (X5, Y5) in the orthogonal coordinate system, respectively.

The FMCW processing unit 43 writes polar coordinates and Cartesian coordinates corresponding to the peaks of the peak numbers Pn1 to Pn5 in the measurement result table 400, and outputs the measurement result table 400 to the calculation unit 45.

On the other hand, if the FMCW processing unit 43 cannot detect a peak having an intensity equal to or higher than the threshold Thfm when analyzing the processed spectrum, the FMCW processing unit 43 writes the measurement result table 400 without writing anything in the measurement result table 400. Output to the calculation unit 45.

The calculation unit 45 estimates the position of the object this time based on the position of the object estimated in the past. More specifically, the calculation unit 45 estimates the position of the object using, for example, a time series filter that uses the position, speed, and moving direction of the object as variables. Here, the said variables are the 1st state variable and 2nd state variable mentioned later. Further, the calculation unit 45 recognizes the position of each sub area, for example.

FIG. 8 is a diagram showing an example of a tracking result table showing a result of tracking an object by the calculation unit in the radio wave sensor according to the embodiment of the present invention.

Referring to FIG. 8, in the tracking result table 401, a data aggregate indicating the state of the object is listed for each object to be tracked. The data collection includes each data about the corresponding object. Specifically, the data aggregate includes an object identifier, a tracking state, a first state variable, a second state variable, and a transition time. Each of the first state variable and the second state variable includes coordinates x, y, speed v, and moving direction φ.

In this example, the tracking result table 401 includes three data aggregates having object identifiers P1, P2, and P3, respectively. The details of the tracking state, the first state variable, the second state variable, and the transition time will be described later.

FIG. 9 is a diagram showing an example of the transition route of the tracking state set in the data aggregate by the arithmetic unit in the radio wave sensor according to the embodiment of the present invention.

With reference to FIG. 9, the calculation unit 45 updates the tracking state for each measurement cycle τ. More specifically, the calculation unit 45 maintains the pedestrian candidate state, transitions to the pedestrian candidate state, specifies as a stopped object, or causes the data aggregate whose tracking state is the pedestrian candidate state to disappear. .. Here, “erasing” means deleting the corresponding data aggregate from the tracking result table 401.

Further, the calculation unit 45 maintains the pedestrian state or eliminates the pedestrian state for the data aggregate whose tracking state is the pedestrian state. Here, “erasing” means deleting the corresponding data aggregate from the tracking result table 401.

When the tracking state is set to the pedestrian candidate state and when the tracking state is set to the pedestrian state, the calculation unit 45 writes the set time in the corresponding transition time column in the tracking result table 401.

FIG. 10 is a diagram showing an example of a time-series change of the input value and the output value of each process performed in the arithmetic unit according to the embodiment of the present invention.

With reference to FIG. 10, when the data set is listed in the tracking result table 401, the calculation unit 45 sets the data set for each measurement cycle τ such as time (t−τ), t, (t+τ). Time update processing, validation gate processing (hereinafter also simply referred to as gate processing), and observation update processing are performed on the body.

The details of the time update process, the gate process, and the observation update process, and the details of the input value and the output value in these processes will be described later. Further, the time updating process and the gate process are performed every measurement period τ. On the other hand, the observation update process may not be performed every measurement period τ.

Referring again to FIG. 6, the calculation unit 45 performs time update processing and observation update processing on the data aggregate by using, for example, a Kalman filter as the time series filter. Note that the calculation unit 45 is not limited to the Kalman filter and may perform the time update process and the observation update process using, for example, a particle filter.

[Time update processing]
Here, the time update process at time t will be described. The same applies to the time update processing at times (t−τ), (t+τ), and the like.

As illustrated in FIG. 10, the calculation unit 45 uses the output value of the observation update process at time (t−τ) as an input value to perform the time update process of estimating the error distribution of the position of the object at time t.

The calculation unit 45 performs a time update process for each data aggregate included in the tracking result table 401. That is, the calculation unit 45 selects one data aggregate in the tracking result table 401 and performs time update processing on the selected data aggregate.

For example, the calculation unit 45 calculates the second state represented by the following equation (2), which is calculated in the observation update processing at the time (t−τ) and has x, y, v, φv of the second state variables as components. The variable vector r<t-1|t-1> is held.

The second state variable vector r<t-1|t-1> may not be calculated. Specifically, for example, it is a case where the observation update process is not performed at the time (t−τ), or the selected data aggregate is a data aggregate newly added to the tracking result table 401.

In such a case, the calculation unit 45 uses the second state variable vector calculated in the latest past. In addition, when the second state variable vector has not been calculated in the past, the calculation unit 45 uses the second state variable vector having an initial value described later as a component.

Further, the calculation unit 45 holds an input vector u represented by the following expression (3), which has a predetermined acceleration a and a predetermined angular velocity ω as components.

The calculation unit 45 calculates the first state variable vector r<t|t−1> at time t using the state equation shown in the following equation (4).

Here, f<t-1> is a non-linear operator whose variables are the second state variable vector r<t-1|t-1> and the input vector u. Further, x<t|t-1>, y<t|t-1>, v<t|t-1>, and φv<t|t-1> are the first state variable vector r<t|t-. 1> component. Further, f1<t|t-1>, f2<t|t-1>, f3<t|t-1>, and f4<t|t-1> are f<t-1>(r<t- 1|t−1>, u).

The calculation unit 45 calculates the calculated x<t|t-1>, y<t|t-1>, v<t|t-1>, and φv<t|t-1> in the tracking result table 401. Write in the x, y, v, and φv fields of the first state variable corresponding to the selected data aggregate.

Further, for example, the calculation unit 45 holds the second error covariance matrix P<t-1|t-1> calculated at the time (t−τ).

The second error covariance matrix P<t-1|t-1> may not be calculated. Specifically, for example, it is a case where the observation update process is not performed at the time (t−τ), or the selected data aggregate is a data aggregate newly added to the tracking result table 401.

In such a case, the calculation unit 45 uses the second error covariance matrix calculated in the latest past. If the second error covariance matrix has not been calculated in the past, the calculation unit 45 uses the second error covariance matrix having a predetermined initial value as a component.

The calculation unit 45 uses the following equation (5) to calculate the first error covariance at time t from the second error covariance matrix P<t−1|t−1> and the covariance matrix Q of the input vector u. The matrix P<t|t-1> is calculated.

Here, the covariance matrix Q is shown by the following equation (6).

Qa and Qω are predetermined values. Further, F<t-1> and G<t-1> are respectively expressed by the following equations (7) and (8).

Since f<t-1> is a non-linear operator, it is possible to directly obtain the first error covariance matrix P<t|t-1> from the second error covariance matrix P<t-1|t-1>. Have difficulty. F<t-1> and G<t-1> are used to solve this difficulty.

That is, the calculation unit 45, in the time updating process, the second state variable vector r<t-1|t-1> and the second error covariance matrix P<t-1|t-1 at time (t-[tau]). >, the first state variable vector r<t|t-1> and the first error covariance matrix P<t|t-1> at time t are calculated.

[Gate processing]
The calculation unit 45 performs a gate process to determine whether the position of the object measured by the measurement unit 46, that is, the positional relationship between the measured position and the estimated position that is the estimated position of the object satisfies the first predetermined condition. ..

Specifically, the calculation unit 45 performs a gate process for determining whether or not the distance based on the difference between the measured position and the estimated position is equal to or greater than a predetermined value.

Specifically, the arithmetic unit 45 determines whether or not a peak satisfying the predetermined condition C1 is observed in the gate process. Here, the predetermined condition C1 is Mahalanobis, which is a distance based on the difference between the estimated position based on the first state variable vector r<t|t-1> calculated in the time update process and the measured position based on the observed peak. The distance is below a threshold based on the chi-square test.

Here, the gate processing at time t will be described, but the same applies to the gate processing at times (t−τ), (t+τ), and the like.

The calculation unit 45 performs a gate process for each data aggregate included in the tracking result table 401.

More specifically, the calculation unit 45 creates a measurement position vector zobs<t> shown in the following Expression (9) for each peak shown in the measurement result table 400. In this example, the calculation unit 45 creates five measurement position vectors zobs<t> corresponding to the peak numbers Pn1 to Pn5 in the measurement result table 400.

When the measurement result table 400 does not include a peak, the calculation unit 45 determines that the positional relationship between the measurement position and the estimated position does not satisfy the first predetermined condition, and ends the gate process.

The calculation unit 45 selects, for example, one data aggregate in the tracking result table 401, and the first state variable of the selected data aggregate, that is, the first state variable vector r<t|t−1>, and the following equation. A calculation position vector zcal<t> is created using the observation equation shown in (10).

Then, the calculation unit 45 uses, for each measurement position vector zobs<t>, the difference between the measurement position vector zobs<t> and the calculated position vector zcal<t> by using the following formula (11), specifically, An observation prediction error vector zerr<t> indicating a difference is calculated. In this example, the calculation unit 45 calculates five observation prediction error vectors zerr<t> corresponding to the peak numbers Pn1 to Pn5.

In addition, the calculation unit 45 uses the first error covariance matrix P<t|t−1> corresponding to the selected data aggregate and the following Expression (12), and the observation prediction error variance matrix S< Calculate t>.

Here, the covariance matrix R is represented by the following Expression (13).

The variances Rx and Ry in the covariance matrix R are predetermined values and are set to 0.7 and 1.8, respectively. This is because the pedestrian Tgt2 on the pedestrian crossing PC1 basically moves straight along the Y axis, but the speed changes, so the variance Ry of the coordinate y in the state variable is more than the variance Rx of the coordinate x in the state variable. The reason is that it is likely to be large.

The calculation unit 45 calculates the Mahalanobis distance as a distance based on the difference between the measured position vector zobs<t> and the calculated position vector zcal<t>. Specifically, the calculation unit 45 calculates the Mahalanobis distance Rm for each detected peak using the created observation prediction error variance matrix S<t> and the following Expression (14). In this example, the calculation unit 45 calculates five Mahalanobis distances Rm corresponding to the peak numbers Pn1 to Pn5.

Further, the calculation unit 45 sets a rejection area α used in the chi-square test, and calculates χ^2(1-α) that is a threshold value based on the rejection area α and the set chi-square distribution table. Here, "a^b" means y to the x-th power.

The calculation unit 45 confirms whether or not there is a Mahalanobis distance Rm that satisfies the predetermined condition C1 among the calculated Mahalanobis distances Rm. More specifically, the calculation unit 45 confirms whether or not the Mahalanobis distance Rm that satisfies the following expression (15) is present.

When confirming that the Mahalanobis distance Rm that satisfies the predetermined condition C1 does not exist, the calculation unit 45 determines not to perform the observation update process for the selected data aggregate.

On the other hand, when the calculation unit 45 confirms that the Mahalanobis distance Rm that satisfies the predetermined condition C1 exists, it determines to perform the observation update process for the selected data aggregate, and also performs the following process.

That is, of the Mahalanobis distances Rm satisfying the predetermined condition C1, the smallest Mahalanobis distance Rm is specified, and the peak number of the peak corresponding to the specified Mahalanobis distance Rm and the observation prediction error vector zerr<t> are specified.

The calculation unit 45 creates and holds correspondence information indicating a correspondence relationship between the selected data aggregate, the specified peak number, and the observation prediction error vector zerr<t>.

The calculation unit 45 is configured to calculate the Mahalanobis distance as the distance based on the difference between the measured position and the estimated position, but the present invention is not limited to this. The calculation unit 45 may calculate the distance between the measured position and the estimated position as a distance based on the difference between the measured position and the estimated position, or may calculate the distance other than the Mahalanobis distance. ..

[Observation update processing]
The calculation unit 45 performs the observation update processing on the data set that has been decided to perform the observation update processing. Here, the observation update processing at time t will be described, but the same applies to the observation update processing at times (t−τ), (t+τ), and the like.

The calculation unit 45, for each data set that is determined to perform the observation update process, the first error covariance matrix P<t|t−1> and the observation prediction error variance matrix S< that correspond to the target data set. The Kalman gain K<t> is calculated by substituting t> into the following equation (16).

The calculation unit 45 identifies the observation prediction error vector zerr<t> corresponding to the target data set based on the correspondence information held, and identifies the identified observation prediction error vector zerr<t> as the target data set. The second state variable vector r<t|t> is calculated by substituting the corresponding first state variable vector r<t|t-1> and the calculated Kalman gain K<t> into the following equation (17). To do.

The calculation unit 45 writes each component of the calculated r<t|t> into the columns of x, y, v, φv of the second state variable corresponding to the target data aggregate in the tracking result table 401.

In addition, the calculation unit 45 stores the first error covariance matrix P<t|t-1> and the observed prediction error variance matrix S<t> corresponding to the target data set, and the calculated Kalman gain K<t>. The second error covariance matrix P<t|t> is calculated by substituting into the following equation (18).

[Recording process]
FIG. 11 is a diagram showing an example of a processing result history table updated by the calculation unit in the radio wave sensor according to the embodiment of the present invention.

With reference to FIG. 11, the calculation unit 45 holds a processing result history table 403, and when the gate processing of each data aggregate included in the tracking result table 401 is completed, for example, the tracking state is calculated for each data aggregate. , The gate processing result, the estimated position, and the peak intensity are written in the processing result history table 403.

Here, the gate processing result indicates whether or not the target data set satisfies the predetermined condition C1 in the gate processing. The estimated position is a calculated position vector zcal<t> corresponding to the target data set. The peak intensity is the observed intensity of the peak corresponding to the target data set.

[Tracking status transition judgment processing]
FIG. 12 is a diagram showing an example of a stationary object list updated by the calculation unit in the radio wave sensor according to the embodiment of the present invention.

With reference to FIG. 9, FIG. 11 and FIG. 12, the calculation unit 45 holds a stopped object list 402. The calculation unit 45 performs a transition determination process for determining the transition of the tracking state of the data aggregate based on the time transition of the gate processing result.

Specifically, for example, when the update of the processing result history table 403 is completed, the calculation unit 45, based on the value of each gate processing result within the latest predetermined time in the processing result history table 403, the tracking state of the data aggregate. To determine the transition.

For example, when the tracking state of the target data aggregate is the pedestrian candidate state and the number of times the “false” gate processing result is shown is the predetermined number of times NL or more within the latest predetermined time TL. , The data aggregate is erased (transition Tr1).

When the tracking state of the target data aggregate is the pedestrian candidate state and the number of times the “true” gate processing result is shown is the predetermined number NM or more within the latest predetermined time TM. , The tracking state of the data aggregate is transited to a pedestrian state (transition Tr2) or specified as a stationary object (transition Tr4).

More specifically, the calculation unit 45 performs the following processing when the target data aggregate satisfies the predetermined condition C2. Here, the predetermined condition C2 is that the estimated position of each processing timing corresponding to the target data set, that is, the variance of each component of the calculated position vector zcal<t> is less than or equal to a predetermined value, and corresponds to the data set. That is, the variance of the peak intensity at each processing timing is less than or equal to a predetermined value.

That is, the calculation unit 45 determines that the object corresponding to the target data aggregate has not moved, and identifies the data aggregate as a stationary object. Then, the calculation unit 45 deletes the data aggregate from the tracking result table 401 and adds the data aggregate to the stationary object list 402.

On the other hand, when the predetermined condition C2 is not satisfied, the calculation unit 45 determines that the object corresponding to the target data aggregate is moving, and changes the tracking state of the data aggregate from the pedestrian candidate state to the pedestrian state. Make a transition.

In addition, when the tracking state of the target data aggregate is the pedestrian state and the number of times indicating the “false” gate processing result is the predetermined number of times NN or more within the latest predetermined time TN, the calculation unit 45, The data aggregate is extinguished (transition Tr3).

Here, the predetermined time TM is, for example, 1 second. The predetermined times TN and TL are preferably longer than the predetermined time TM. Part or all of the predetermined times TL, TM, and TN may have the same value or different values.

Further, the predetermined number of times NL, NM, NN may be once or plural times. More specifically, the upper limit value of the predetermined number of times NL, NM, NN is, for example, a value obtained by dividing the predetermined time TL, TM, TN by the measurement cycle τ. When the predetermined number of times NL, NM, and NN have the upper limit value, the transition of the tracking state of the data set occurs when the same result of the gate processing is continuously obtained at the predetermined times TL, TM, and TN, respectively. Further, the predetermined number of times NL, NM, NN may be partially or wholly the same value, or may be mutually different values.

[Association processing]
For example, when the transition determination process is completed, the calculation unit 45 performs the association process for associating the peak in the measurement result table 400 with the data aggregate based on the association information.

More specifically, the calculation unit 45 identifies the corresponding peak number for each data aggregate in the tracking result table 401 based on the correspondence information. Then, the calculation unit 45 writes the object identifier included in the corresponding data aggregate in the column of the object identifier corresponding to the specified peak number in the measurement result table 400.

Further, the calculation unit 45 specifies the peak number corresponding to the data aggregate in the stopped matter list 402 based on the stopped matter list 402. More specifically, the calculation unit 45 compares, for example, x and y of the first state variables in the stationary object list 402 with the observation position of the rectangular coordinates in the measurement result table 400, and based on the comparison result, the stationary object. The peak number corresponding to the data aggregate in the list 402 is specified.

Then, the calculation unit 45 writes the object identifier included in the corresponding data aggregate in the column of the object identifier corresponding to the specified peak number in the measurement result table 400.

On the other hand, when the peak number corresponding to the data aggregate in the stopped substance list 402 cannot be specified, the calculation unit 45 deletes the data aggregate from the stopped substance list 402.

The calculation unit 45 confirms the measurement result table 400, and performs the following processing on the peak for which the object identifier is not written, that is, the peak with the peak number of Pn4 in this example.

That is, for example, the calculation unit 45 indicates that the intensity of the peak in which the object identifier is not written indicates the intensity corresponding to the reflection cross-sectional area of the pedestrian Tgt2, and the position corresponding to the peak is the pedestrian crossing PC1 or the sub-area SAis or SAes. If it is located inside, it is determined that the type of the object corresponding to the peak is highly likely to be the pedestrian Tgt2.

The calculation unit 45 creates a new data aggregate corresponding to the peak determined to be likely to be the pedestrian Tgt2, and adds the created data aggregate to the tracking result table 401.

More specifically, the calculation unit 45 sets a value corresponding to the measurement position as the initial value of the second state variable, for example.

Specifically, the calculation unit 45 sets a second state variable having an initial value corresponding to the measurement position corresponding to the peak number Pn4 for the data aggregate corresponding to the peak of the peak number Pn4.

For example, when the measurement position (X, Y) is included in the sub-area SAes or SAer, the calculation unit 45 sets x, y, v, φv as X, Y, 4.0, respectively, as the initial value of the second state variable. Set to meters per second and 0°.

In addition, for example, when the measurement position (X, Y) is included in the sub-area SAis or SAir, the calculation unit 45 sets x, y, v, φv as X, Y, 4 as the initial value of the second state variable. Set to 0.0 meters per second and 180°.

Further, the calculation unit 45 sets NA indicating no allocation as the initial value of x, y, v, φv in the first state variable.

Note that, for example, when the intensity of the peak in which the object identifier is not written indicates the intensity according to the reflection cross-section of the automobile Tgt1, the calculation unit 45 is highly likely to be the automobile Tgt1 corresponding to the peak. Then, a data aggregate used for tracking the automobile Tgt1 may be created.

Referring again to FIG. 6, when 2FCW processing unit 44 receives power spectra FS11 to FS14, FS21 to FS24 and phase spectra PS11 to PS14, PS21 to PS24 from FFT processing unit 42, it performs the following processing.

That is, the 2FCW processing unit 44 performs peak detection processing on the power spectrum FS11, for example. More specifically, the calculation unit 45 analyzes the power spectrum FS11 and attempts to detect a peak having an intensity equal to or higher than the threshold Thhtf.

The 2FCW processing unit 44 calculates the measurement position, which is the position of the object corresponding to the detected peak, for each peak.

More specifically, the 2FCW processing unit 44 calculates the distance Ltf corresponding to the detected peak according to the method described in Non-Patent Document 1 and Non-Patent Document 2.

Specifically, the 2FCW processing unit 44 acquires the peak frequency Ftf of the detected peak from the power spectrum FS11. The 2FCW processing unit 44 acquires the phase at the peak frequency Ftf in the phase spectra PS11 and PS21, for example. The 2FCW processing unit 44 calculates the distance Ltf based on the acquired phase difference between the two phases.

In addition, the 2FCW processing unit 44 calculates the azimuth angle φtf corresponding to the detected peak according to the beam former method, the MUSIC (MULTI Single Signal Classification) method and the Capon method described in Non-Patent Document 3.

Specifically, the 2FCW processing unit 44 acquires the phases at the peak frequencies Ftf in the phase spectra PS11 to PS14, for example, and calculates the azimuth angle φtf corresponding to the detected peak based on each acquired phase.

The 2FCW processing unit 44 calculates (Xtf, Ytf), which is the measurement position in the Cartesian coordinates, based on the calculated distance Ltf and azimuth angle φtf.

Further, the 2FCW processing unit 44 calculates the velocity vtf of the object corresponding to the detected peak based on the peak frequency Ftf according to the method described in Non-Patent Document 1 and Non-Patent Document 2.

The 2FCW processing unit 44 creates 2-frequency CW result information indicating the intensity, bandwidth, velocity vtf, and measurement position (Xtf, Ytf) of the detected one or more peaks, and the created 2-frequency CW result information is detected by the detection unit. Output to 7.

Referring again to FIG. 3, the detection unit 7 determines that the positional relationship between the measurement position and the estimated position satisfies the first predetermined condition in the undetermined state before determining whether the object is the detection target. When the number of times is the predetermined number of times NM or more within the predetermined time TM, it is determined that the object is the detection target.

Further, for example, in the undetermined state before determining whether or not the object is the detection target, the detection unit 7 determines that the number of times that the positional relationship between the measurement position and the estimated position satisfies the first predetermined condition is predetermined. When the number of times is less than the predetermined number of times NL within the time TL, or when the number of times the positional relationship satisfies the second predetermined condition after determining that the object is the detection target object is less than the predetermined number of times NN within the predetermined time TN, It is determined that the object is not the detection target. Here, the first predetermined condition and the second predetermined condition are, for example, the same.

In addition, the detection unit 7 uses the two-frequency CW method by the measuring unit 46 when a stationary object that is a stopped object is measured by the measuring unit 46 using the FM-CW method in the target area A1, for example. Based on the measurement result of the object different from the stationary object, it is determined whether the object different from the stationary object is the detection target object.

In addition, for example, the detection unit 7 uses the measurement unit 46 from when the measurement unit 46 measures the new object using the FM-CW method until when the new object is determined to be the detection target. Whether or not the object is the detection target is determined based on the measurement result of the object using the dual frequency CW method.

More specifically, the detection unit 7 recognizes the position of each sub area, for example. Further, the detection unit 7 determines that the object is the pedestrian Tgt2 based on the contents of the tracking result table 401 and the stopped object list 402 created by the calculation unit 45, and the two-frequency CW result information received from the 2FCW processing unit 44. It is determined whether or not, and the pedestrian Tgt2 at the pedestrian crossing PC1 is detected based on the determination result.

FIG. 13 is a diagram showing an example of a transition route of the detection state set by the detection unit in the radio wave sensor according to the embodiment of the present invention.

With reference to FIG. 13, the detection unit 7 can set “undetermined state”, “no pedestrian state” and “state with pedestrian”, and transition between these states is possible. However, here, the transition from the “state without pedestrian” to the “state with pedestrian” is excluded.

The detection unit 7 sets the detection state for each measurement cycle τ based on the contents of the tracking result table 401 and the stopped object list 402.

More specifically, when the data collection is included in the stopped object list 402, the detection unit 7 determines that there is an area that is difficult to detect, and sets the detection state to the “undetermined state”.

On the other hand, when the stopped object list 402 does not include the data aggregate, the detection unit 7 performs the following processing.

That is, the detection unit 7 sets the detection state to the “no pedestrian state” when the data aggregate is not included in the tracking result table 401. That is, the radio wave sensor 101 detects that the pedestrian Tgt2 does not exist at the pedestrian crossing PC1.

Further, when the tracking result table 401 includes a data aggregate, the detection unit 7 sets the detection state to the “undetermined state” when the tracking states of the data aggregate are all “pedestrian candidate states”. ..

On the other hand, when at least one of the data aggregates included in the tracking result table 401 satisfies the predetermined condition C4, the detection unit 7 sets the detection state to the “pedestrian presence state”. That is, the radio wave sensor 101 detects the presence of the pedestrian Tgt2 at the crosswalk PC1. Here, the predetermined condition C4 is that the tracking state of the data aggregate is “pedestrian state” and the position of the object corresponding to the data aggregate is included in the pedestrian crossing PC1.

The detection unit 7 determines that the object is the detection target when the “pedestrian presence state” is set.

Further, when the detection unit 7 is set to the “undetermined state”, the detection unit 7 determines whether or not the object is the detection target object based on the 2-frequency CW result information received from the 2FCW processing unit 44.

More specifically, the detection unit 7 determines that the object is the detection target object when the content of the two-frequency CW result information satisfies the predetermined condition C3. That is, the radio wave sensor 101 detects the presence of the pedestrian Tgt2 at the crosswalk PC1.

Here, the predetermined condition C3 is, for example, the measurement position (Xtf, Ytf) indicated by the two-frequency CW result information is included in the pedestrian crossing PC1, and the peak intensity, the bandwidth, and the velocity vtf indicated by the two-frequency CW result information are included. Is included in each corresponding predetermined range.

On the other hand, when the content of the dual frequency CW result information does not satisfy the predetermined condition C3, the detection unit 7 detects that the pedestrian Tgt2 does not exist in the pedestrian crossing PC1. The detection unit 7 transmits the detection result to the relay device 141.

[motion]
The radio wave sensor 101 includes a computer, and an arithmetic processing unit such as a CPU in the computer reads a program including some or all of the steps of the flowcharts described below from a memory (not shown) and executes the program. The program of this device can be installed from the outside. The program of this device is distributed while being stored in a recording medium.

FIG. 14 is a flowchart that defines an operation procedure when the radio wave sensor according to the embodiment of the present invention detects an object in a unit sequence.

With reference to FIG. 14, first, the radio wave sensor 101 waits until the power spectra FS31 to FS34 and the phase spectra PS31 to PS34, which are the results of the FM-CW method, are output (NO in step S102).

When the result of the FM-CW method is output (YES in step S102), the radio wave sensor 101 performs peak detection processing (step S104).

Next, when the tracking result table 401 includes a data aggregate (YES in step S106), the radio wave sensor 101 selects one data aggregate from the tracking result table 401 (step S108).

Next, when the tracking state of the selected data aggregate is the pedestrian state, the radio wave sensor 101 performs the pedestrian state process described later (step S112).

On the other hand, when the tracking state of the selected data aggregate is the pedestrian candidate state, the radio wave sensor 101 performs the pedestrian candidate state process described later (step S114).

Next, when the radio wave sensor 101 performs the pedestrian state process (step S112) or the pedestrian candidate state process (step S114), whether or not all the data aggregates in the tracking result table 401 have been selected. Is determined (step S116).

Next, when the radio wave sensor 101 determines that all the data aggregates in the tracking result table 401 have not been selected (NO in step S116), another data aggregate is selected from the tracking result table 401 ( Step S108).

On the other hand, the radio wave sensor 101 does not include the data aggregate in the tracking result table 401 (NO in step S106) or determines that all the data aggregates in the tracking result table 401 have been selected (YES in step S116). ), and a matching process is performed (step S118).

Next, the radio wave sensor 101 performs a detection determination process described later (step S120).

FIG. 15 is a flowchart defining an operation procedure when the radio wave sensor according to the embodiment of the present invention performs a pedestrian candidate state process. FIG. 15 shows details of the operation in step S114 of FIG.

First, the radio wave sensor 101 performs time update processing on the selected data aggregate (step S202).

Next, the radio wave sensor 101 performs the gate process based on the result of the time update process, and when the predetermined condition C1 is satisfied in the gate process, that is, when the result of the gate process is true (YES in step S204). The observation update processing is performed on the selected data aggregate (step S206).

Next, if the result of the gate processing is false (NO in step S204) or if the observation update processing is performed (step S206), the radio wave sensor 101 determines whether or not a predetermined condition is satisfied in each gate processing within the latest predetermined time TL. It is determined whether the number of times C1 is satisfied is NL or more (step S208).

When the radio wave sensor 101 determines that the number of times the predetermined condition C1 is satisfied is smaller than NL in each gate process within the latest predetermined time TL (NO in step S208), the selected data aggregate is extracted from the tracking result table 401. The deletion is completed and the pedestrian candidate state processing ends.

On the other hand, when the radio wave sensor 101 determines that the number of times the predetermined condition C1 is satisfied is NL or more in each gate process within the latest predetermined time TL (YES in step S208), the following process is performed.

That is, the radio wave sensor 101 determines whether or not the number of times the predetermined condition C1 is satisfied is NM or more in each gate process within the latest predetermined time TM (step S212).

When the radio wave sensor 101 determines that the number of times the predetermined condition C1 is satisfied is smaller than NM in each gate process within the latest predetermined time TM (NO in step S212), the pedestrian candidate state process ends.

On the other hand, when the radio wave sensor 101 determines that the number of times the predetermined condition C1 is satisfied is NM or more in each gate process within the latest predetermined time TM (YES in step S212), the following process is performed.

That is, when the selected data aggregate satisfies the predetermined condition C2, that is, when the object corresponding to the selected data aggregate is stopped (YES in step S214), the radio wave sensor 101 tracks the selected data aggregate. The data aggregate is deleted from the result table 401 and the data aggregate is added to the stopped article list 402. Then, the radio wave sensor 101 ends the pedestrian candidate state process (step S216).

On the other hand, when the object corresponding to the selected data aggregate is not stopped (NO in step S214), the radio wave sensor 101 sets the tracking state of the selected data aggregate to the pedestrian state and performs the pedestrian candidate state process. Is completed (step S218).

FIG. 16 is a flowchart defining an operation procedure when the radio wave sensor according to the embodiment of the present invention performs a pedestrian state process. FIG. 16 shows details of the operation in step S112 of FIG.

First, the radio wave sensor 101 performs time update processing on the selected data aggregate (step S302).

Next, the radio wave sensor 101 performs the gate process based on the result of the time update process, and when the predetermined condition C1 is satisfied in the gate process, that is, when the result of the gate process is true (YES in step S304). The observation update process is performed on the selected data aggregate (step S306).

Next, if the result of the gate process is false (NO in step S304) or if the observation update process is performed (step S306), the radio wave sensor 101 determines whether a predetermined condition is satisfied in each gate process within the latest predetermined time TN. It is determined whether the number of times C1 is satisfied is NN or more (step S308).

When the radio wave sensor 101 determines that the number of times the predetermined condition C1 is satisfied is smaller than NN in each gate process within the latest predetermined time TN (NO in step S308), the selected data aggregate is extracted from the tracking result table 401. Delete and end the pedestrian state process.

On the other hand, when the radio wave sensor 101 determines that the number of times the predetermined condition C1 is satisfied is NN or more in each gate process within the latest predetermined time TN (YES in step S308), the pedestrian state process ends.

FIG. 17 is a flowchart defining an operation procedure when the radio wave sensor according to the embodiment of the present invention performs the detection determination process. FIG. 17 shows details of the operation in step S120 of FIG.

First, the radio wave sensor 101 determines whether or not there is an area that is difficult to detect. Specifically, the radio wave sensor 101 confirms whether or not the data collection is included in the stationary object list 402 (step S402).

Next, when the radio wave sensor 101 determines that there is no region that is difficult to detect (NO in step S402), the radio wave sensor 101 confirms whether or not a data aggregate is included in the tracking result table 401 (step S404).

Next, when the radio wave sensor 101 confirms that the data aggregate is not included in the tracking result table 401 (NO in step S404), the detection state is set to the pedestrian-free state, and the pedestrian Tgt2 is set on the pedestrian crossing PC1. Is determined not to exist, and the detection determination process ends (step S406).

On the other hand, when the radio wave sensor 101 confirms that the data aggregate is included in the tracking result table 401 (YES in step S404), the radio sensor 101 performs the following process.

That is, in the radio wave sensor 101, when the data aggregate satisfying the predetermined condition C4 is included in the tracking result table 401, that is, the data aggregate in which the tracking state is the pedestrian state and the corresponding object is located at the pedestrian crossing PC1. When it is included in the tracking result table 401 (YES in step S408), the detection state is set to the pedestrian presence state, it is determined that the pedestrian Tgt2 exists in the pedestrian crossing PC1, and the detection determination process ends (step S410). ..

On the other hand, the radio wave sensor 101 determines that there is an area that is difficult to detect (YES in step S402) or determines that a data aggregate satisfying the predetermined condition C4 is not included in the tracking result table 401 (NO in step S408). ), the detection state is set to the undetermined state (step S412).

Next, the radio wave sensor 101 acquires dual frequency CW result information (step S414).

Next, when the content of the acquired two-frequency CW result information satisfies the predetermined condition C3 (YES in step S416), the radio wave sensor 101 determines that the pedestrian Tgt2 is present in the pedestrian crossing PC1, and ends the detection determination process. (Step S420).

On the other hand, when the content of the acquired 2-frequency CW result information does not satisfy the predetermined condition C3 (NO in step S416), the radio wave sensor 101 determines that the pedestrian Tgt2 does not exist in the pedestrian crossing PC1 and ends the detection determination process. Yes (step S418).

In the radio wave sensor according to the embodiment of the present invention, the measuring unit 46 is configured to be able to periodically measure the position of the object in the target area A1, but the present invention is not limited to this. The measurement unit 46 may have a configuration capable of irregularly measuring the position of the object in the target area A1.

Further, in the radio wave sensor according to the embodiment of the present invention, the first predetermined condition and the second predetermined condition are the same, but the present invention is not limited to this. The first predetermined condition and the second predetermined condition may be different. Specifically, for example, a threshold value that is different from the threshold value used for the gate processing performed on the pedestrian candidate state data aggregate is used for the gate processing performed on the pedestrian state data aggregate. Good.

By the way, in the object identification device described in Patent Document 1, since the type of the object is identified using the sound wave or electromagnetic wave irradiation processing and detection processing and the image processing, the apparatus configuration becomes complicated and costly. There is a problem.

Further, with the pedestrian detector described in Patent Document 2, it is possible to detect the presence or absence of a pedestrian passing through the boundary, which is the detection area, from the sidewalk side toward the roadside, but crossing the roadside. It is difficult to detect pedestrians on the sidewalk.

On the other hand, for example, a method of transmitting a radio wave to a target area including a pedestrian crossing and detecting a pedestrian on the pedestrian crossing based on the radio wave received from the target area can be considered.

However, when a pedestrian is located away from the radio wave sensor, the radio wave sensor receives a weak radio wave from the pedestrian, which may make it difficult for the radio wave sensor to detect the pedestrian. is there.

Further, for example, when an automobile passes between the radio wave sensor and a pedestrian, the pedestrian does not exist within the line of sight of the radio wave sensor. Will be difficult to do.

On the other hand, in the radio wave sensor according to the embodiment of the present invention, the measurement unit 46 can measure the position of the object in the target area A1 regularly or irregularly. The calculation unit 45 estimates the position of the object this time based on the position of the object estimated in the past. Then, the detection unit 7 determines the number of times that the positional relationship between the position of the object measured by the measurement unit 46 and the position of the object estimated by the calculation unit 45 satisfies the first predetermined condition, the predetermined number of times within the predetermined time TM. When it is NM or more, it is determined that the object is the detection target.

With such a configuration, the object can be detected without performing image processing, so that the radio wave sensor can have a low cost and a simple configuration. Therefore, the object in the target area can be detected more accurately with a simple and low-cost configuration. Further, as described above, the position of the object in the target area A1 is repeatedly measured, and when the measured position is frequently present in the vicinity of the estimated position, the object is determined to be the detection target by the configuration of the estimated position. Even if there is no measurement position in the vicinity, it can be prevented that the object is immediately determined to be not the detection target. As a result, the strength of the radio wave from the detection target received by the radio wave sensor 101 is weak, or the vehicle Tgt1 passes between the radio wave sensor 101 and the detection target. Even when it is difficult to measure, the detection target can be detected stably.

Further, in the radio wave sensor according to the embodiment of the present invention, the detection unit 7 detects whether the positional relationship satisfies the first predetermined condition less than the predetermined number NL within the predetermined time TL or the object is a detection target. After determining that the object is the object, if the number of times the positional relationship satisfies the second predetermined condition is smaller than the predetermined number of times NN within the predetermined time TN, it is determined that the object is not the detection target.

In this way, after determining that the object is the detection target, even if there is no measurement position near the estimated position, for example, it is not immediately determined that the object is not the detection target. If the measurement position in the vicinity is low in frequency, it is possible to mistakenly determine that the object is not the detection target even though the object is the detection target, by the configuration that determines that the object is not the detection target. It can be reduced. Further, for example, even if there is a measurement position in the vicinity of the estimated position, without determining immediately that the object is a detection target, if the frequency of the measurement position in the vicinity of the estimated position is low, The configuration in which it is determined that the object is not the detection target can reduce the possibility of erroneously determining that the object is the detection target even though the object is not the detection target.

In addition, in the radio wave sensor according to the embodiment of the present invention, calculation unit 45 estimates the position of the object using a time-series filter that uses the position, speed, and moving direction of the object as variables. Then, the initial value of the variable is a value corresponding to the position of the object measured by the measuring unit 46.

In this way, the position of the object can be estimated more accurately by the configuration using the time series filter that uses the initial value according to the position of the object as a variable.

Further, in the radio wave sensor according to the embodiment of the present invention, the transmission unit 1 uses the radio wave generated using the FM-CW modulation method and the radio wave generated using the dual frequency CW modulation method in the target area A1. Can be sent to. The receiver 2 receives a radio wave. The measuring unit 46 can measure the position of the object using the FM-CW method, based on the radio wave received by the receiving unit 2. Then, the detection unit 7 measures two frequencies by the measurement unit 46 from the time when the measurement unit 46 measures the new object using the FM-CW method to the time when it is determined that the new object is the detection target. Whether or not the object is a detection target is determined based on the measurement result of the object using the CW method.

With such a configuration, an undetermined period from when a new object is measured using the FM-CW method until it is determined that the object is a detection target is supplemented by determination using the two-frequency CW method. Therefore, it is possible to realize detection without omission of determination.

Here, for example, as shown in FIG. 2, when the automobile Tgt1 having a large reflection cross-sectional area stops so that a part of itself is included in the target area A1, the vicinity of the automobile Tgt1 is a detection difficult region of the pedestrian Tgt2. It becomes RD. Here, the detection difficult region RD is determined based on the distance resolution and the angular resolution of the radio wave sensor 101, for example. When the pedestrian Tgt2 is located in the detection difficulty region RD, the radio wave sensor 101 receives a radio wave in which a strong reflected wave from the automobile Tgt1 and a weak reflected wave from the pedestrian Tgt2 are superimposed, and thus separates these reflected waves. Becomes difficult. Therefore, it becomes difficult for the radio wave sensor 101 to detect the pedestrian Tgt2 located in the detection difficulty region RD.

On the other hand, in the radio wave sensor according to the embodiment of the present invention, the transmitting unit 1 transmits the radio wave generated using the FM-CW modulation method and the radio wave generated using the 2-frequency CW modulation method. It can be transmitted to the target area A1. The receiver 2 receives a radio wave. The measuring unit 46 can measure the position of the object using the FM-CW method, based on the radio wave received by the receiving unit 2. Then, in the target area A1, the detection unit 7 uses the two-frequency CW method by the measurement unit 46 when the stopped object, which is the stopped object, is measured by the measurement unit 46 using the FM-CW method. It is determined whether or not the object different from the stationary object is the detection target object based on the measurement result of the object different from.

With such a configuration, since the stopped object exists in the target area A1, a detection difficult area of the detection object occurs in the vicinity of the stopped object. For example, although the detection object exists in the detection difficult area, Even when the situation where the measurement position does not exist near the estimated position continues, the object is measured using the two-frequency CW method that can favorably detect the object having the velocity component with respect to the radio wave sensor 101, that is, the moving object. Therefore, it is possible to correctly determine whether or not the object moving in the detection-difficult region is a detection target.

Further, the radio wave sensor 101 according to the embodiment of the present invention does not include an estimation unit, and the detection unit 7 positions the position of the object measured by the measurement unit 46 and the position of the object estimated by the estimation unit. A configuration may be used in which the condition that the relationship satisfies the first predetermined condition is not less than a predetermined number of times within a predetermined time period.

Specifically, in the radio wave sensor according to the embodiment of the present invention, the transmitter 1 transmits the radio wave generated using the FM-CW modulation method and the radio wave generated using the two-frequency CW modulation method. It can be sent to the target area. The receiver 2 receives a radio wave. The measuring unit 46 can measure the position of the object in the target area A1 regularly or irregularly based on the radio wave received by the receiving unit 2. Then, in the target area A1, the detection unit 7 uses the two-frequency CW method by the measurement unit 46 when the stopped object, which is the stopped object, is measured by the measurement unit 46 using the FM-CW method. It is determined whether or not the moving object is the detection target object based on the measurement result of the moving object which is the object in the target area A1 different from.

With such a configuration, the object can be detected without performing image processing, so that the radio wave sensor can have a low cost and a simple configuration. Therefore, it is possible to achieve the object of the present invention of more accurately detecting an object in the target area with a simple and low-cost configuration. Further, as described above, while the stopped object such as the stopped vehicle and the electric pole can be detected, the detection object difficult detection area RD occurs in the vicinity of the stopped object because the stopped object exists in the target area A1. When a stationary object is measured by the FM-CW method in which it is difficult to detect an object in the detection difficult region RD, it is difficult to detect the stationary object, while moving in the vicinity of the stationary object. The weaknesses of these methods can be complemented by a configuration that determines whether or not a moving object is a detection target by using a two-frequency CW method capable of detecting an object. Is present as a stop object at a position beyond the stop line, and even if the detection-difficult region RD occurs in the vicinity of the vehicle, whether the object moving in the detection-difficult region RD is the pedestrian Tgt2 or not. It can be judged correctly.

It should be considered that the above-described embodiments are illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

The above description includes the following additional features.

[Appendix 1]
A measuring unit that can measure the position of an object in the target area regularly or irregularly,
An estimation unit that estimates the position of the object this time based on the position of the object estimated in the past,
When the number of times that the positional relationship between the position of the object measured by the measuring unit and the position of the object estimated by the estimating unit satisfies the first predetermined condition is a predetermined number of times or more within a predetermined time, A detection unit that determines that the object is a detection target,
The target area includes a pedestrian crossing,
The pedestrian crossing is provided near the intersection,
The detection target is a human being or a bicycle,
The measuring unit can periodically measure the position of the object in the target area,
The estimating unit estimates the position of the object this time based on the position of the object estimated in the previous time,
The detection unit, in the undetermined state before determining whether the object is the detection target, the position of the object measured by the measurement unit and the position of the object estimated by the estimation unit When the number of times that the distance based on the difference is less than or equal to a predetermined value is the predetermined number of times or more within the predetermined time, the object is determined to be the previous detection target object.

[Appendix 2]
When the number of times that the positional relationship satisfies the first predetermined condition in the undetermined state is smaller than a predetermined number of times within a predetermined time period or after the detection unit determines that the object is a detection target, The radio wave sensor according to Appendix 1, wherein when the number of times that the positional relationship satisfies the second predetermined condition is smaller than the predetermined number of times within a predetermined time, it is determined that the object is not the detection target.
[Appendix 3]
The radio wave sensor further includes
A transmission unit capable of transmitting an electric wave generated using a modulation method of FM-CW (Frequency Modulated-Continuous Wave) method and an electric wave generated using a modulation method of two-frequency CW method to the target area,
It has a receiver that receives radio waves,
The measurement unit can measure the position of the object using the FM-CW method based on the radio wave received by the reception unit,
In the target area, the detection unit uses the two-frequency CW method by the measurement unit when a stationary object that is the stopped object is measured by the measurement unit using the FM-CW method. The radio wave sensor according to supplementary note 1 or supplementary note 2, which determines whether or not the object different from the stationary object is a detection target object based on a measurement result of the object different from the stationary object.

[Appendix 4]
A transmission unit capable of transmitting an electric wave generated using an FM-CW modulation method and an electric wave generated using a two-frequency CW modulation method to a target area;
A receiver that receives radio waves,
Based on the radio wave received by the receiving unit, a measuring unit capable of measuring the position of the object in the target area regularly or irregularly,
In the target area, when a stationary object that is a stopped object is measured by the measuring unit using the FM-CW method, the object different from the stationary object using the dual-frequency CW method by the measuring unit. Based on the measurement result of the moving object that is an object in the area, a detection unit that determines whether or not the moving object is a detection target,
The target area includes a pedestrian crossing,
The pedestrian crossing is provided near the intersection,
The detection target is a human being or a bicycle,
The measuring unit can periodically measure the position of the object in the target area,
The stationary object is a radio wave sensor, which is a vehicle.

1 transmitter 2 receiver 3 differential signal generator 4 controller 5 signal processor 7 detector 21 transmitting antenna 22 power amplifier 23 directional coupler 24 VCO
25 Voltage Generator 26 Switch 31 Reception Antenna 32 Low Noise Amplifier 33 Mixer 34 IF Amplifier 35 Low Pass Filter 36 A/D Converter (ADC)
41 memory 42 FFT processing unit 43 FMCW processing unit 44 2FCW processing unit 45 arithmetic unit (estimation unit)
46 Measuring unit 101 Radio wave sensor 141 Relay device 151 Signal control device 152 Wireless transmission device 153 Antenna 161 Pedestrian traffic light 301 Safe driving support system

Claims (6)

A measuring unit that can measure the position of an object in the target area regularly or irregularly,
An estimation unit that estimates the position of the object this time based on the position of the object estimated in the past,
When the number of times that the positional relationship between the position of the object measured by the measuring unit and the position of the object estimated by the estimating unit satisfies the first predetermined condition is a predetermined number of times or more within a predetermined time, A detection unit that determines that the object is a detection target ,
A transmission unit capable of transmitting an electric wave generated using an FM-CW modulation method and an electric wave generated using a two-frequency CW modulation method to the target area;
It has a receiver that receives radio waves,
The measurement unit can measure the position of the object using the FM-CW method based on the radio wave received by the reception unit,
The detection unit is configured to perform the measurement by the measurement unit between the measurement of the new object by the measurement unit using the FM-CW method and the determination that the new object is the detection target. A radio wave sensor for determining whether or not the object is a detection target object based on a measurement result of the object using a frequency CW method . When the number of times the positional relationship satisfies the first predetermined condition is smaller than a predetermined number of times within a predetermined time period or when the detection unit determines that the object is a detection target, the detection unit determines that the positional relationship is the second. The radio wave sensor according to claim 1, wherein when the number of times satisfying the predetermined condition is smaller than a predetermined number within a predetermined time, the object is determined not to be a detection target. The estimation unit estimates the position of the object using a time-series filter that uses the position, speed and moving direction of the object as variables,
The radio wave sensor according to claim 1, wherein the initial value of the variable is a value corresponding to the position of the object measured by the measuring unit. A transmission unit capable of transmitting an electric wave generated using a modulation method of FM-CW (Frequency Modulated-Continuous Wave) method and an electric wave generated using a modulation method of two-frequency CW method to a target area,
A receiver that receives radio waves,
Based on the radio wave received by the receiving unit, a measuring unit capable of measuring the position of the object in the target area regularly or irregularly,
In the target area, when a stationary object that is a stopped object is measured by the measuring unit using the FM-CW method, the object different from the stationary object using the dual-frequency CW method by the measuring unit. A radio wave sensor, comprising: a detection unit that determines whether or not the moving object is a detection target object based on a measurement result of the moving object that is an object in the area. A detection program used in a radio wave sensor,
Computer,
A measuring unit that can measure the position of an object in the target area regularly or irregularly,
An estimation unit that estimates the position of the object this time based on the position of the object estimated in the past,
When the number of times that the positional relationship between the position of the object measured by the measuring unit and the position of the object estimated by the estimating unit satisfies the first predetermined condition is a predetermined number of times or more within a predetermined time, A detection unit that determines that the object is a detection target ,
A transmission unit capable of transmitting an electric wave generated using an FM-CW modulation method and an electric wave generated using a two-frequency CW modulation method to the target area;
A receiver that receives radio waves,
Is a program to function as
The measurement unit can measure the position of the object using the FM-CW method based on the radio wave received by the reception unit,
The detection unit is configured to perform the measurement by the measurement unit between the measurement of the new object by the measurement unit using the FM-CW method and the determination that the new object is the detection target. A detection program for determining whether or not the object is a detection target based on the measurement result of the object using the frequency CW method . A detection program used in a radio wave sensor capable of transmitting a radio wave generated using an FM-CW modulation method and a radio wave generated using a two-frequency CW modulation method to a target area and used in a radio wave sensor for receiving a radio wave. ,
Computer,
Based on the received radio waves, a measurement unit capable of measuring the position of the object in the target area regularly or irregularly,
In the target area, when a stationary object that is a stopped object is measured by the measuring unit using the FM-CW method, the object different from the stationary object using the dual-frequency CW method by the measuring unit. Based on the measurement results of the moving object that is an object in the area, a detection unit that determines whether the moving object is a detection target,
Detection program to function as.

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