JP6662415B2 - Radio wave sensor, detection method and detection program - Google Patents

Description

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

  Japanese Patent Application Laid-Open No. 2012-247215 (Patent Document 1) discloses an object identification device that is mounted on a vehicle and identifies the type of an object existing around the vehicle. The object identification device includes an object including information on a reflection intensity and a distance to an object around the own vehicle, obtained by irradiating a sound wave or an electromagnetic wave around the own vehicle and detecting a reflected wave of the sound wave or the electromagnetic wave. Information and 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.

Takayuki Inaba, Tetsuro Kirimoto, "Millimeter Wave Radar for Vehicles", Automotive Technology, February 2010, Vol. 64, No. 2, 74-79 Koji Quarter and two others, "Application of expanding millimeter-wave technology", [online], [searched April 9, 2014], Internet <URL: http: // www. spc. co. jp / spc / pdf / giho21_09. pdf> Ikumitsu Jimbo and two others, "Study on application of dual-frequency ICW radar to safe driving support system", Proceedings of the 2013 IEICE General Conference 2013 General Conference Proceedings, March 2013, lecture number: B- 2-23, P265

JP 2012-247215 A

  However, for example, when the object identification device described in Patent Document 1 is installed in a place where the power that can be supplied is limited, if the power consumption of the object identification device exceeds the limit value, the object identification device There is a case where it is difficult to operate stably. Therefore, there is a need for a radio wave sensor such as an object identification device that can operate with low power consumption.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a radio wave sensor, a detection method, and a detection program capable of correctly detecting an object while suppressing power consumption. is there.

  (1) In order to solve the above problem, a radio wave sensor according to an aspect of the present invention includes a transmitting unit that transmits a radio wave to a target area, a receiving unit that receives a radio wave from the target area, and a receiving unit that A detection unit that performs a detection process for detecting an object in the target area based on the received radio wave, and a control unit that performs control to change an execution interval of the detection process based on a result of the detection process And

  (13) In order to solve the above problem, a detection method according to an aspect of the present invention is a detection method in a radio wave sensor, in which a radio wave is transmitted to a target area, and a radio wave from the target area is received. A step of performing a detection process for detecting an object in the target area based on the received radio wave, and a step of performing control to change an execution interval of the detection process based on a result of the detection process And

  (14) In order to solve the above problem, a detection program according to an aspect of the present invention is a detection program used in a radio wave sensor that transmits a radio wave to a target area and receives a radio wave from the target area, A step of performing, on the computer, a detection process for detecting an object in the target area based on the received radio wave; and a step of performing control for changing an execution interval of the detection process based on a result of the detection process And a program for executing the above.

  The present invention can be realized not only as a radio wave sensor having such a characteristic processing unit, but also as a semiconductor integrated circuit that realizes a part or all of the radio wave sensor, or as a system including a radio wave sensor. Or you can.

  According to the present invention, an object can be correctly detected while suppressing power consumption.

FIG. 1 is a diagram showing a configuration of a signal control system according to the first embodiment of the present invention. FIG. 2 is a diagram showing a configuration of the radio wave sensor in the signal control system according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a control unit in the radio wave sensor according to the first embodiment of the present invention. FIG. 4 is a diagram illustrating a configuration of the transmission wave processing unit in the transmission unit according to the first embodiment of the present invention. FIG. 5 is a diagram illustrating an example of a change in the operation mode by the radio wave sensor according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating an example of a change in the operation mode by the radio wave sensor according to the first embodiment of the present invention. FIG. 7 is a diagram illustrating an example of a normal target area and an enlargement target area where the radio wave sensor according to the first embodiment of the present invention can detect a target. FIG. 8 is a diagram illustrating a configuration of the received wave processing unit in the receiving unit according to the first embodiment of the present invention. FIG. 9 is a diagram illustrating an example of the arrangement of the transmitting antenna, the receiving antenna, and the object according to the first embodiment of the present invention. FIG. 10 is a diagram illustrating a configuration of a signal processing unit in the radio wave sensor according to the first embodiment of the present invention. FIG. 11 is a diagram illustrating a configuration of a detection unit in the radio wave sensor according to the first embodiment of the present invention. FIG. 12 is a diagram showing a configuration of a modified example of the radio wave sensor according to the first embodiment of the present invention. FIG. 13 is a diagram illustrating a configuration of a control unit in a modified example of the radio wave sensor according to the first embodiment of the present invention. FIG. 14 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the first embodiment of the present invention. FIG. 15 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the first embodiment of the present invention. FIG. 16 is a diagram illustrating a configuration of a modified example of the radio wave sensor according to the first embodiment of the present invention. FIG. 17 is a diagram illustrating a configuration of a control unit in a modification of the radio wave sensor according to the first embodiment of the present invention. FIG. 18 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the first embodiment of the present invention. FIG. 19 is a diagram illustrating an example of a change in an operation mode according to a modified example of the radio wave sensor according to the first embodiment of the present invention. FIG. 20 is a diagram illustrating an example of the direction of the directivity of the tilt-variable transmitting antenna in the modification example of the radio wave sensor according to the first embodiment of the present invention. FIG. 21 is a flowchart that defines an operation procedure when the radio wave sensor according to the first embodiment of the present invention detects a target in a target area according to an operation mode. FIG. 22 is a flowchart that defines an operation procedure when the radio wave sensor according to the first embodiment of the present invention detects an object in the enlargement target area in the enlargement detection mode. FIG. 23 is a flowchart that defines an operation procedure when the radio wave sensor according to the first embodiment of the present invention detects an object in the normal target area in the normal detection mode. FIG. 24 is a diagram illustrating a configuration of a radio wave sensor according to the second embodiment of the present invention. FIG. 25 is a diagram illustrating a configuration of the transmission wave processing unit in the transmission unit according to the second embodiment of the present invention. FIG. 26 is a diagram illustrating an example of a change in the operation mode by the radio wave sensor according to the second embodiment of the present invention. FIG. 27 is a diagram illustrating an example of a change in the operation mode by the radio wave sensor according to the second embodiment of the present invention. FIG. 28 is a diagram illustrating an example of a pulse signal generated by the transmission unit and the reception unit according to the second embodiment of the present invention. FIG. 29 is a diagram illustrating a configuration of a reception wave processing unit in the reception unit according to the second embodiment of the present invention. FIG. 30 is a diagram illustrating a configuration of a detection unit in a radio wave sensor according to the second embodiment of the present invention. FIG. 31 is a diagram illustrating a configuration of a modification of the radio wave sensor according to the second embodiment of the present invention. FIG. 32 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the second embodiment of the present invention. FIG. 33 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the second embodiment of the present invention. FIG. 34 is a diagram illustrating a configuration of a modified example of the radio wave sensor according to the second embodiment of the present invention. FIG. 35 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the second embodiment of the present invention. FIG. 36 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the second embodiment of the present invention.

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

  (1) A radio wave sensor according to an embodiment of the present invention includes a transmitting unit for transmitting a radio wave to a target area, a receiving unit for receiving a radio wave from the target area, and a radio wave sensor based on the radio wave received by the receiving unit. A detection unit that performs a detection process for detecting an object in the target area; and a control unit that performs control to change an execution interval of the detection process based on a result of the detection process.

  With such a configuration, the frequency of the detection processing can be reduced within a range that does not adversely affect the result of the detection processing, so that the target object can be correctly detected while suppressing power consumption by the detection processing.

  (2) Preferably, the transmitting unit continuously transmits radio waves during a first period, stops transmitting radio waves during a second period, and alternately performs the first period and the second period. Repeatedly, the control unit changes the execution interval by changing the length of the second period based on the result of the detection processing.

  As described above, by changing the length of the second period in which the power consumption is small while maintaining the length of the first period, the power consumption can be suppressed while preventing the accuracy of the detection processing from deteriorating. Can be.

  (3) Preferably, the transmitting unit repeatedly transmits a pulsed radio wave which is a pulse-shaped radio wave, and the control unit changes the transmission interval of the pulsed radio wave based on a result of the detection processing to execute the execution. Change the interval.

  As described above, by changing the transmission interval of the repeatedly transmitted pulse radio waves in accordance with the result of the detection processing, it is possible to suppress power consumption while avoiding deterioration in the accuracy of the detection processing.

  (4) Preferably, the control unit determines whether or not the detection unit has transitioned from a state in which the object is not detected to a state in which the object is detected, and performs the execution based on a result of the determination. The radio wave sensor according to any one of claims 1 to 3, wherein the interval is shortened.

  With such a configuration, when an object is present in the object area, the temporal transition of the detection result of the object can be acquired with high accuracy. In addition, an efficient detection process can be performed by increasing the frequency of the detection process in a situation where a high-frequency detection process is required after the detection of the target object.

  (5) Preferably, the control unit determines whether or not the detection unit has transitioned from a state in which the target object is detected to a state in which the object is not detected, and performs the execution based on a result of the determination. Increase the interval.

  As described above, the configuration in which the frequency of the detection processing is reduced in a situation in which the high-frequency detection processing is not required after the detection of the target object is not performed enables efficient detection processing.

  (6) Preferably, the control unit changes the range of the target area according to whether a predetermined condition including a condition regarding a result of the detection processing is satisfied.

  With such a configuration, the range of the target area can be changed to an appropriate range according to the result of the detection processing.

  (7) More preferably, the control unit changes the range of the target area by changing the transmission power of the transmission unit.

  With such a configuration, the range of the target area can be changed without using a mechanical operation, so that the mechanism of a transmitting device such as an antenna can be simplified.

  (8) More preferably, the control unit changes the range of the target area by changing the directivity of the antenna in the transmitting unit.

  With such a configuration, it is possible to extend the reach of the radio wave without increasing the transmission power of the radio wave, so that an increase in power consumption due to a change in the range of the target area can be suppressed.

  (9) More preferably, the control unit changes the range of the target area by changing the direction of the antenna in the transmitting unit.

  With such a configuration, the beam direction of the radio wave can be changed by a simple method, and the range of the target area can be changed flexibly.

  (10) Preferably, the control unit changes the execution interval by changing a suspension period of power supply to a circuit for performing the detection processing.

  As described above, by stopping the circuit for performing the detection processing during the period in which the detection processing is not performed, power consumption can be suppressed while changing the execution interval of the detection processing.

  (11) Preferably, the radio wave sensor further includes a battery, and the control unit performs control to change an execution interval of the detection process based on a remaining amount of the battery and a result of the detection process.

  As described above, with the configuration in which the frequency of the detection process is changed according to the remaining amount of the battery, the object can be correctly detected while extending the time until the remaining amount of the battery becomes zero. That is, the operation time of the radio wave sensor can be extended.

  (12) More preferably, the radio wave sensor further includes a battery, and the control unit makes a determination regarding the stop of the power supply based on the remaining amount of the battery.

  With such a configuration, the power consumption in the circuit can be changed according to the remaining amount of the battery, so that the time until the remaining amount of the battery becomes zero can be extended. That is, the operation time of the radio wave sensor can be extended.

  (13) A detection method according to an embodiment of the present invention is a detection method in a radio wave sensor, in which a step of transmitting a radio wave to a target area, a step of receiving a radio wave from the target area, and a step of Performing a detection process for detecting a target object in the target area based on the detection process, and controlling to change an execution interval of the detection process based on a result of the detection process.

  With such a configuration, the frequency of the detection processing can be reduced within a range that does not adversely affect the result of the detection processing, so that the target object can be correctly detected while suppressing power consumption by the detection processing.

  (14) The detection program according to the embodiment of the present invention is a detection program used in a radio wave sensor that transmits a radio wave to a target area and receives a radio wave from the target area. A step of performing a detection process for detecting a target object in the target area based on the result of the detection process, and a step of performing control of changing an execution interval of the detection process based on a result of the detection process. is there.

  With such a configuration, the frequency of the detection processing can be reduced within a range that does not adversely affect the result of the detection processing, so that the target object can be correctly detected while suppressing power consumption by the detection processing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated. Further, at least some of the embodiments described below may be arbitrarily combined.

<First embodiment>
[Configuration and basic operation]
FIG. 1 is a diagram showing a configuration of a signal control system according to the first embodiment of the present invention.

  Referring to FIG. 1, signal control system 201 includes radio wave sensor 101, signal control device 151, pedestrian signal light 161, power generation unit 121, and battery B1. The signal control device 151 and the pedestrian signal light 161 in the signal control system 201 constitute a traffic signal, and are installed, for example, near the main road Rd1.

  The radio wave sensor 101 functions as a detection sensor that detects the target Tgt in the normal target area An1 and the expansion target area Ae1. Hereinafter, each of the normal target area An1, the enlargement target area Ae1, and the enlargement target area Ae2 described later is also referred to as a target area.

  The target area is, for example, an area set by a sensor installer who is an installer of the radio wave sensor 101. Specifically, as shown in FIG. 1, for example, the sensor installer sets the pedestrian Tgt2 on the pedestrian crossing PC1 located between the sidewalks Pv1 and Pv2 installed across the main road Rd1 as the target object Tgt. In this case, the area including the crosswalk PC1 is set as the normal target area An1.

  In addition, for example, when the pedestrian Tgt2 on the pedestrian crossing PC1 and the pedestrian Tgt2 located near the pedestrian crossing PC1 are set as the target Tgt, the sensor installer sets the following area as the expansion target area Ae1 or Ae2.

  That is, for example, the sensor installer determines a part of the sidewalk Pv2 which is a part of the sidewalk adjacent to the pedestrian crossing PC1 and located on the opposite side of the radio wave sensor 101 with respect to the main road Rd1, that is, the waiting area As, and the pedestrian crossing. The area including PC1 is set as the enlargement target area Ae1 or Ae2.

  The sensor installer may set, for example, an area including a part of the crosswalk PC1 as the target area. In addition, for example, when the radio wave sensor 101 is attached to a car and the pedestrian Tgt2 and the car Tgt1 located in front of the car are set as the target Tgt, the sensor installer may set a predetermined range in front of the car. Set as an area.

  The power generation unit 121 is, for example, a solar power generation device. When receiving the sunlight, the power generation unit 121 generates power from the energy of the received sunlight, and outputs the generated power to the battery B1 via a power line (not shown). The power generation unit 121 may be, for example, a wind power generation device.

  Battery B1 stores power received from power generation unit 121. The battery B1 supplies the operating power of the radio wave sensor 101 based on the stored power.

  The radio wave sensor 101 is installed, for example, near the main road Rd1. Specifically, the radio wave sensor 101 is fixed to, for example, a support P1 installed near the main road Rd1.

  The radio wave sensor 101 operates using power received from the battery B1 via a power line (not shown). The radio wave sensor 101 may operate using, for example, electric power received from a system.

  The pedestrian signal light 161 and the signal control device 151 are fixed to, for example, the pillar P1. The radio wave sensor 101 and the signal control device 151 are connected by, for example, a signal line (not shown). The signal control device 151 and the pedestrian signal light 161 are connected by, for example, a signal line (not shown). The radio wave sensor 101 may be installed on the main road Rd1 or may be mounted on a car.

  The radio wave sensor 101 performs, for example, a detection process of detecting a target Tgt in a target area. More specifically, the radio wave sensor 101 transmits a radio wave to a target area including the pedestrian crossing PC1 under the control of the signal control device 151, for example. The target object Tgt is, for example, a pedestrian Tgt2 or the like. Note that the target object Tgt may be, for example, an automobile Tgt1.

  The target object Tgt is located, for example, in the target area, and reflects a radio wave transmitted from the radio wave sensor 101. The radio wave sensor 101 receives, for example, a radio wave reflected by the target Tgt, and intermittently performs a detection process of detecting the target Tgt in the target area based on the received radio wave. The radio wave sensor 101 transmits, for example, a detection result that is a result of the detection process to the signal control device 151, and changes the execution interval of the detection process based on the detection result.

  Under the control of the signal control device 151, the pedestrian signal light 161 lights and displays, for example, "recommend" or "stop" for the pedestrian Tgt2 crossing the pedestrian crossing PC1.

  When receiving the detection result from the radio wave sensor 101, the signal control device 151 controls the pedestrian signal light 161 based on the received detection result.

  For example, when the detection result indicates that the pedestrian Tgt2 has entered the waiting area As, the signal control device 151 turns on the "recommendation" in the pedestrian signal light 161. Thereby, the pedestrian Tgt2 can be passed preferentially.

  In addition, for example, when the remaining time for turning on the “recommendation” in the pedestrian signal light 161 is short, the signal control device 151 extends the remaining time when the pedestrian Tgt2 is detected in the target area. The signal control device 151 may, for example, notify the pedestrian Tgt2 by voice that the remaining time for turning on “recommend” is short.

  In addition, for example, when “stop” is lit in the pedestrian signal light 161, when the pedestrian Tgt 2 is detected in the target area, the signal control device 151 notifies the pedestrian Tgt 2 of the danger to the pedestrian Tgt 2 by voice. Warning.

  Note that the signal control device 151 may provide a service to the vehicle 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 is detected in the target area, the signal control device 151 gives a warning to the automobile Tgt1 that the pedestrian Tgt2 on the pedestrian crossing PC1 should be watched for.

[Configuration of radio wave sensor]
FIG. 2 is a diagram showing a configuration of the radio wave sensor in the signal control system according to the first embodiment of the present invention.

  Referring to FIG. 2, radio wave sensor 101 includes a transmission unit 1, a reception unit 2, a signal processing unit 3, a detection unit 4, and a control unit 5. The transmission unit 1 includes a transmission wave processing unit 10 and a transmission antenna 11. Receiving section 2 includes a receiving wave processing section 12 and a receiving antenna 13. The transmission antenna 11 and the reception antenna 13 are not limited to the configuration provided in the radio wave sensor 101, and may be provided outside the radio wave sensor 101.

  FIG. 3 is a diagram illustrating a configuration of a control unit in the radio wave sensor according to the first embodiment of the present invention.

  Referring to FIG. 3, control unit 5 includes a supply power intermittent unit 80, an amplification factor control unit 81, a comprehensive determination unit 82, and a battery remaining amount measurement unit 83. Comprehensive determination unit 82 includes a mode setting unit 84 and an execution interval setting unit 85.

  FIG. 4 is a diagram illustrating a configuration of the transmission wave processing unit in the transmission unit according to the first embodiment of the present invention.

  Referring to FIG. 4, transmission wave processing section 10 includes a radio wave generation section 31, a directional coupler 32, and a power amplifier 33. The radio wave generator 31 includes a frequency switch 35, a voltage generator 36, and a voltage controlled oscillator 37.

  With reference to FIGS. 2 to 4, the radio wave sensor 101 is, for example, Takayuki Inaba and Tetsuro Kirimoto, “Millimeter Wave Radar for Cars”, Automotive Technology, February 2010, Vol. 74-79 (Non-Patent Document 1), or Koji Quarter and two others, "Application of expanding millimeter-wave technology", [online], [Search on April 9, 2014], Internet <URL: http: // / Www. spc. co. jp / spc / pdf / giho21_09. pdf> (Non-Patent Document 2), a detection process of detecting a target Tgt in a target area is performed according to a two-frequency CW (Continuous Wave) method. Details of the detection processing will be described later.

  The transmission wave processing unit 10 in the transmission unit 1 uses the power received from the battery B1 via the control unit 5 to transmit a radio wave to the target area via the transmission antenna 11 under the control of the control unit 5. The reception wave processing unit 12 in the reception unit 2 receives a radio wave from the target area via the reception antenna 13.

  The detection unit 4 performs a detection process for detecting the target Tgt in the target area based on the radio waves received by the reception unit 2. The detection unit 4 outputs the result of the detection processing to the control unit 5 and the signal control device 151.

  The control unit 5 performs control to change the execution interval of the detection process based on, for example, the result of the detection process received from the detection unit 4 and the remaining amount of the battery in the battery B1. Change the length of the suspension period for suspension.

  More specifically, the control unit 5 changes the execution interval by, for example, changing the suspension period of the power supply to the radio wave generation unit 31 and the power amplifier 33 in the transmission wave processing unit 10. The radio wave generator 31 and the power amplifier 33 correspond to, for example, a circuit for performing a detection process.

  The battery remaining amount measuring unit 83 in the control unit 5 shown in FIG. 3 measures the remaining amount of the battery B1 and outputs the measured remaining amount measuring result to the comprehensive determining unit 82.

[Execution interval setting]
FIG. 5 is a diagram illustrating an example of a change in the operation mode by the radio wave sensor according to the first embodiment of the present invention. FIG. 5 shows an operation in a case where the operation mode is switched from the normal detection mode to the enlargement detection mode at a time (t1 + 68) milliseconds, for example.

  FIG. 6 is a diagram illustrating an example of a change in the operation mode by the radio wave sensor according to the first embodiment of the present invention. FIG. 6 shows an operation when the operation mode is switched from the enlargement detection mode to the normal detection mode at, for example, time (t2 + 125) milliseconds.

  Referring to FIGS. 5 and 6, general judgment section 82 sets an operation mode based on the result of the detection processing received from detection section 4.

  More specifically, the mode setting unit 84 in the comprehensive judgment unit 82 changes the operation mode based on the result of the detection process received from the detection unit 4 into a normal detection mode in which the detection process is repeated at the normal execution interval In, and The mode is set to one of the enlargement detection modes in which the detection process is repeated at the enlargement execution interval Ie.

  Here, the normal execution interval In is, for example, the sum of the length of the transmission period Ttn and the length of the stop period Thn. Further, the expansion execution interval Ie is, for example, the sum of the length of the transmission period Tte and the length of the suspension period The.

  The length of the transmission period Ttn and the length of the transmission period Tte are the same, for example. Further, the length of the suspension period The is longer than the length of the suspension period Thn. Therefore, the enlarged execution interval Ie is longer than the normal execution interval In.

  Hereinafter, each of the transmission period Ttn and the transmission period Tte is also referred to as a transmission period Tt. In addition, each of the suspension period Thn and the suspension period The is also referred to as a suspension period Th.

  The mode setting unit 84 determines, for example, whether or not the detection unit 4 has transitioned from a state in which the target Tgt is detected to a state in which the target Tgt is not detected, and based on the result of the determination, expands the operation mode. Set the mode.

  More specifically, for example, in a state where the normal detection mode is set, the mode setting unit 84 receives, from the detection unit 4, target non-detection information indicating that the target Tgt in the target area is not detected. The above determination is made based on the number of times, and the normal detection mode is switched to the enlargement detection mode based on the result of the determination.

  More specifically, for example, when the number of times the object non-detection information is continuously received from the detection unit 4 becomes equal to or greater than the predetermined threshold value Thc at time (t1 + 68) milliseconds, the mode setting unit 84 determines It is determined that the object Tgt has transitioned to a state in which the object Tgt has not been detected, and the operation mode is switched from the normal detection mode to the enlargement detection mode at time (t1 + 68) milliseconds as shown in FIG.

  Further, the mode setting unit 84 determines, for example, whether or not the detection unit 4 has transitioned from a state in which the target Tgt is not detected to a state in which the target Tgt is detected, and sets the operation mode based on the result of the determination. Set to normal detection mode.

  More specifically, when the mode setting unit 84 receives, from the detection unit 4, target detection information indicating that the target Tgt in the target area has been detected in the state where the enlargement detection mode is set, for example, It is determined that the object Tgt has transitioned to the state in which the object Tgt is detected, and the operation mode is switched from the enlargement detection mode to the normal detection mode at the timing when the object detection information is received.

  Specifically, for example, when receiving the object detection information from the detection unit 4 at time (t2 + 125) milliseconds, the mode setting unit 84 detects the operation mode at time (t2 + 125) milliseconds as shown in FIG. Switch from mode to normal detection mode.

  Further, the comprehensive determination unit 82 makes a determination regarding the stop of power supply to the radio wave generation unit 31 and the power amplifier 33 based on the set operation mode and the remaining amount measurement result received from the battery remaining amount measurement unit 83.

  More specifically, the execution interval setting unit 85 changes the execution interval of the detection process, for example, by changing the stop period Th.

  Specifically, the execution interval setting unit 85 sets the suspension period based on, for example, the current operation mode and the remaining amount measurement result, so that the normal execution interval In of 100 ms and the extended execution of 4000 ms are performed. Set the interval Ie.

  FIG. 7 is a diagram illustrating an example of a normal target area and an enlargement target area where the radio wave sensor according to the first embodiment of the present invention can detect a target.

  Referring to FIG. 7, enlargement execution interval Ie is determined, for example, as follows. That is, the enlargement execution interval Ie is determined based on, for example, the time Tb required for the pedestrian Tgt2 moving on the sidewalk Pv2 to enter the enlargement target area Ae1 and enter the normal target area An1.

  Specifically, for example, when the difference between the length of the expansion target area Ae1 and the length of the normal target area An1 in the cross direction of the pedestrian crossing PC1 is 20 meters, the pedestrian Tgt2 moves at a speed of 5 meters per second. In this case, the time Tb becomes approximately 4000 milliseconds at the maximum. The extension execution interval Ie is determined to be, for example, 4000 milliseconds, which is the maximum value of the time Tb.

  For example, when the remaining battery level measurement result indicates that the remaining battery level is low, specifically, when the remaining battery level is equal to or less than a predetermined value, the execution interval setting unit 85 sets the normal execution interval In and the enlarged execution interval Ie to Set as follows.

  That is, in the normal detection mode, the execution interval setting unit 85 sets a normal execution interval In of 100 ms, for example, as shown in FIGS. A transmission period Ttn and a stop period Thn of 50 milliseconds are set.

  Then, when the operation mode is maintained in the normal detection mode, the execution interval setting unit 85 sets the next normal execution interval In. Thereby, the transmission period Ttn and the stop period Thn are alternately repeated.

  Further, in the enlargement detection mode, for example, in the enlargement detection mode, the execution interval setting unit 85 sets an enlargement execution interval Ie of 4000 milliseconds as shown in FIG. 5 and FIG. A second transmission period Tte and a 3950 millisecond suspension period The are set.

  When the operation mode is maintained in the enlargement detection mode, the execution interval setting unit 85 sets the next enlargement execution interval Ie. Thereby, the transmission period Tte and the suspension period The are repeated alternately.

  On the other hand, the time Tb may be shorter than 4000 milliseconds depending on the route on which the pedestrian Tgt2 moves on the sidewalk Pv2. For this reason, when the remaining amount measurement result indicates that the remaining amount of the battery is sufficient, specifically, when the remaining amount of the battery is larger than the predetermined value, for example, by setting an enlarged execution interval Ie shorter than 4000 milliseconds, It is preferable to increase the frequency of the detection process more than the frequency when the remaining amount of the battery is low.

  Therefore, when the remaining battery level measurement result indicates that the remaining battery level is sufficient, the execution interval setting unit 85 sets the enlarged execution interval Ie to increase the frequency of the detection process more frequently than when the remaining battery level is low. Set as follows.

  That is, in the enlargement detection mode, the execution interval setting unit 85 sets an enlargement execution interval Ie of, for example, 2000 milliseconds, and based on the set enlargement execution interval Ie, a transmission period Tte of 50 milliseconds and a stop of 1950 milliseconds. The period The is set.

  Further, the execution interval setting unit 85 sets the normal execution interval In of 100 milliseconds as shown in FIGS. 5 and 6, for example, for the normal execution interval In, regardless of the remaining battery level.

  Further, for example, when the operation mode is switched, the execution interval setting unit 85 sets the normal execution interval In and the enlarged execution interval Ie as follows. That is, for example, as shown in FIG. 5, the execution interval setting unit 85 changes the operation mode from the normal detection mode to the time (t1 + 68) milliseconds before the time corresponding to the normal execution interval In elapses from the time t1. The following processing is performed when switching to the mode. That is, the execution interval setting unit 85 newly sets, for example, the enlarged execution interval Ie from the time (t1 + 100) milliseconds at which the time corresponding to the normal execution interval In elapses from the time t1 to the time (t1 + 4100) milliseconds. Then, the transmission period Tte and the suspension period The are newly set.

  Further, as shown in FIG. 6, for example, as shown in FIG. 6, the execution interval setting unit 85 changes the operation mode from the enlargement detection mode to the normal detection at time (t2 + 125) milliseconds before the time corresponding to the enlargement execution interval Ie elapses. The following processing is performed when switching to the mode. That is, the execution interval setting unit 85 shortens the enlarged execution interval Ie at the switching time (t2 + 125) milliseconds to the enlarged execution interval Iei of 125 milliseconds, and starts at the time (t2 + 125) milliseconds at the time (t2 + 225) milliseconds. The normal execution interval In up to seconds is newly set, and the transmission period Ttn and the suspension period Thn are newly set.

  The execution interval setting unit 85 can also set other contents for the normal execution interval In and the enlarged execution interval Ie. Further, the execution interval setting unit 85 can also set other contents for the length of the transmission period Tt and the length of the stop period Th.

  Specifically, for example, the execution interval setting unit 85 sets a normal execution interval In of 100 milliseconds, and sets a transmission period Ttn of 100 milliseconds and a stop period Thn of zero milliseconds based on the set normal execution interval In. May be set.

[Control of power supply]
The supply power intermittent unit 80 performs the following processing based on the power supplied from the battery B1. That is, supply power intermittent section 80 supplies power Pcn to radio wave generating section 31 and power amplifier 33 in transmission wave processing section 10 during transmission period Ttn, for example, as shown in FIGS. Further, the supply power intermittent unit 80 supplies, for example, a power Pce higher than the power Pcn to the radio wave generator 31 and the power amplifier 33 during the transmission period Tte. Therefore, radio waves are transmitted from the transmission wave processing unit 10 via the transmission antenna 11 in the transmission periods Ttn and Tte.

  On the other hand, the supply power intermittent unit 80 stops supplying power to the radio wave generation unit 31 and the power amplifier 33 during the suspension periods Thn and The, for example. Therefore, in the suspension periods Thn and The, transmission of radio waves from the transmission wave processing unit 10 is stopped.

[Change range of target area]
The amplification factor control unit 81 changes the range of the target area, for example, according to whether a predetermined condition including a condition regarding a result of the detection processing is satisfied. Specifically, for example, the amplification factor control unit 81 changes the transmission power of the transmission unit 1 by setting the amplification factor of the power amplifier 33 according to the operation mode, thereby changing the range of the target area.

  Specifically, for example, as shown in FIGS. 5 and 6, the amplification factor control unit 81 sets the amplification factor of the power amplifier 33 to Gn in the transmission period Ttn and the suspension period Thn based on the normal execution interval In, Further, the amplification factor of the power amplifier 33 is set to Ge larger than Gn in the transmission period Tte and the suspension period The based on the enlarged execution interval Ie.

  Therefore, the power of the radio wave transmitted from the transmission wave processing unit 10 via the transmission antenna 11 in the transmission period Tte is larger than the power of the radio wave transmitted from the transmission wave processing unit 10 via the transmission antenna 11 in the transmission period Ttn.

  Specifically, a radio wave is transmitted to the enlargement target area Ae1 during the transmission period Tte, and a radio wave is transmitted to the normal target area An1 during the transmission period Ttn. That is, the range of the target area in the transmission period Tte is larger than the range of the target area in the transmission period Ttn.

  In addition, the amplification factor control unit 81 is configured to set the amplification factor of the power amplifier 33 to Gn in the transmission period Ttn and the suspension period Thn, but is not limited thereto. For example, the gain control unit 81 may be configured to set the gain of the power amplifier 33 to Gn at least in the transmission period Ttn.

  Further, the amplification factor control unit 81 is configured to set the amplification factor of the power amplifier 33 to Ge in the transmission period Tte and the suspension period The, but is not limited to this. For example, the gain control unit 81 may be configured to set the gain of the power amplifier 33 to Ge at least in the transmission period Tte.

[Transmission processing of radio waves]
Referring to FIG. 4 again, the transmission wave processing unit 10 in the transmission unit 1 continuously transmits the radio wave via the transmission antenna 11 during the transmission period Tt and transmits the radio wave during the stop period Th under the control of the control unit 5. To stop.

  More specifically, the radio wave generation unit 31 generates a radio wave having a frequency of, for example, a 24 GHz band, that is, a millimeter wave, using the power received from the supply power intermittent unit 80 during the transmission period Tt. Then, the radio wave generator 31 outputs the generated millimeter wave to the directional coupler 32.

  The radio wave generator 31 may generate a radio wave having a frequency of, for example, a 60 GHz band, a 76 GHz band, or a 79 GHz band. Further, the radio wave generating unit 31 may generate a radio wave having a frequency in a microwave band lower than the millimeter wave band, or may generate a radio wave having a frequency in a terahertz band higher than the millimeter wave band. May be.

  More specifically, the frequency switching unit 35 of the radio wave generation unit 31 transmits a switching signal for alternately switching the frequency of a transmission wave, which is a radio wave transmitted from the transmission antenna 11, at a predetermined switching frequency fswt to the voltage generation unit 36 and Output to the signal processing unit 3.

  Specifically, for example, as shown in FIG. 5 and FIG. 6, the frequency switching unit 35 changes the level Ls to a high level and a low level at a switching frequency fswt of 10 kHz, that is, a period of 0.1 ms in the transmission period Tt. The switching signal for switching to the level is output to the voltage generator 36 and the signal processor 3. In the suspension period Th, the level Ls of the switching signal becomes, for example, zero.

  The voltage generator 36 sets, for example, control voltages Vf1 and Vf2 for causing the voltage-controlled oscillator 37 to generate radio waves having predetermined transmission frequencies f1 and f2, respectively. The difference between the transmission frequencies f2 and f1 is, for example, about several megahertz.

  For example, when the level Ls of the switching signal received from frequency switching section 35 is low, voltage generation section 36 generates control voltage Vf1 and outputs generated control voltage Vf1 to voltage controlled oscillator 37. Further, for example, when the level Ls of the switching signal is high, the voltage generation unit 36 generates the control voltage Vf2 and outputs the generated control voltage Vf2 to the voltage control oscillator 37.

  The voltage-controlled oscillator 37 is specifically a VCO (Voltage-controlled oscillator), and generates a millimeter-wave band transmission wave having a frequency corresponding to the control voltages Vf1 and Vf2 received from the voltage generator 36.

More specifically, the voltage controlled oscillator 37 receives the control voltage Vf1 based on the low-level switching signal from the voltage generation unit 36 as shown in FIGS. A transmission wave T1 (t) having the frequency f1 shown in FIG.

Here, φ1 is the initial phase. In Expression (1) and the following expression, t represents time. The voltage controlled oscillator 37 receives the control voltage Vf2 based on the high-level switching signal from the voltage generator 36 as shown in FIGS. 5 and 6, for example. A transmission wave T2 (t) having f2 is generated.

  Here, φ2 is the initial phase. The amplitude of the transmission wave T1 (t) and the amplitude of the transmission wave T2 (t) are both A, for example. The voltage controlled oscillator 37 alternately generates the transmission waves T1 (t) and T2 (t) and outputs the generated waves to the directional coupler 32.

  The directional coupler 32 distributes the transmission waves T1 (t) and T2 (t) received from the radio wave generator 31 to the power amplifier 33 and the receiver 2. The power amplifier 33 amplifies the transmission waves T1 (t) and T2 (t) received from the directional coupler 32 by using the power received from the supply power interrupting unit 80 and set by the amplification factor control unit 81 in the control unit 5. Amplify at a rate.

  Specifically, when the amplification factor is set to Gn by the amplification factor controller 81, the power amplifier 33 amplifies the transmission wave received from the directional coupler 32 at the amplification factor Gn, and has power of, for example, 0 dBm. The transmission waves T1 (t) and T2 (t) are alternately transmitted to the normal target area An1 via the transmission antenna 11.

  Further, when the amplification factor is set to Ge by the amplification factor controller 81, the power amplifier 33 amplifies the transmission wave received from the directional coupler 32 at the amplification factor Ge, and transmits the transmission wave T1 having a power of, for example, 6 dBm. (T) and T2 (t) are alternately transmitted to the enlargement target area Ae1 via the transmission antenna 11.

  As shown in FIG. 1, the transmitting antenna 11 is installed, for example, so that the direction Dn of the directivity is along the transverse direction of the pedestrian crossing PC1. Here, the directionality Dn of the directivity is, for example, a direction from the radio wave sensor 101 to a position Cn substantially at the center of the crosswalk PC1.

  Preferably, transmitting antenna 11 is, for example, a direction in which directionality Dn of directivity is projected onto a surface of pedestrian crossing PC1 in a direction normal to the surface, and a direction in which pedestrian Tgt2 moves on pedestrian crossing PC1 in the target area. vm, that is, the direction vm2 is set to be parallel or anti-parallel.

[Electric wave reception processing]
FIG. 8 is a diagram illustrating a configuration of the received wave processing unit in the receiving unit according to the first embodiment of the present invention.

  Referring to FIG. 8, received wave processing section 12 includes a low noise amplifier 41, a mixer 42, an IF (Intermediate Frequency) amplifier 43, a low-pass filter 44, and an A / D converter (ADC) 45.

  FIG. 9 is a diagram illustrating an example of the arrangement of the transmitting antenna, the receiving antenna, and the object according to the first embodiment of the present invention.

  Referring to FIGS. 8 and 9, reception wave processing section 12 in reception section 2 receives a radio wave from the target area, for example, a reflected wave via reception antenna 13. Here, during the transmission period Tt, the receiving antenna 13 reflects the reflected wave R1 (t) or R2 (t) generated by the target Tgt in the target area reflecting the transmission wave T1 (t) or T2 (t), respectively. ) Can be received.

  Specifically, the receiving antenna 13 may be the same antenna as the transmitting antenna 11 or a different antenna. When the transmitting antenna 11 and the receiving antenna 13 are separate antennas, the receiving antenna 13 may be arranged at a position distant from the transmitting antenna 11, but the transmitting antenna 11 is simplified in order to simplify the configuration of the radio wave sensor 101. It is preferable to be arranged near 11.

  More specifically, the reflected wave received by the receiving antenna 13 includes, for example, a Doppler reflected wave generated by the object Tgt moving in the target area reflecting the transmitted wave transmitted by the transmitting antenna 11. .

  Here, the moving speed of the target Tgt along the direction approaching or moving away from the radio wave sensor 101 is defined as a detection target speed vd. In other words, the component of the relative speed of the target Tgt with respect to the receiving antenna 13 along the direction approaching or moving away from the radio wave sensor 101 is the detection target speed vd.

  For example, if the speed of the target Tgt with respect to the receiving antenna 13 is defined as a relative speed vt, the detection target speed vd is represented by an inner product of a unit vector nd in the direction from the target Tgt to the receiving antenna 13 and the relative speed vt. . In addition, the radio wave sensor 101 may be fixed to an object that does not move with respect to the ground, such as the column P1, or may be fixed to an object that moves with respect to the ground. For example, when the radio wave sensor 101 is fixed to the column P1, the receiving antenna 13 and the target area are fixed with respect to the ground, so the relative speed vt is also the relative speed of the target Tgt with respect to the ground.

  The frequencies f1r and f2r of the Doppler reflected waves from the target Tgt received by the receiving antenna 13 are shifted with respect to the frequencies f1 and f2 of the transmission waves in accordance with the detection target speed vd corresponding to the target Tgt. Further, the amplitude of the Doppler reflected wave is an amplitude corresponding to the reflection cross-sectional area σ of the target Tgt.

More specifically, in a case where the transmission wave T1 (t) is represented by Expression (1), for example, when the reception antenna 13 is arranged near the transmission antenna 11, the Doppler reflected wave R1d (t) As shown in Patent Literature 1 or Non-Patent Literature 2, it is represented by the following equation (3).

  Here, L is the distance between the receiving antenna 13 and the target Tgt. c is the speed of light. a is a value determined by, for example, the amplitude A and the wavelength of the transmission wave T1 (t), the antenna gains of the transmission antenna 11 and the reception antenna 13, the distance L, the reflection cross section σ, and the like.

  The frequency f1r of the Doppler reflected wave R1d (t) is a frequency obtained by adding f1 × (2 × vd / c) to the frequency f1 of the transmission wave T1 (t) as shown in Expression (3). Specifically, when the target Tgt moves in a direction approaching the receiving antenna 13, the frequency f1r becomes higher than the frequency f1 because vd becomes positive, and the target Tgt moves in a direction away from the receiving antenna 13. At this time, the frequency f1r becomes lower than the frequency f1 because vd becomes negative.

The reflected wave R1 (t) received by the receiving antenna 13 generally includes a Doppler reflected wave R1d (t) and a non-Doppler reflected wave R1nd (t) from a portion other than the object Tgt. Therefore, the reflected wave R1 (t) is a superposition of the Doppler reflected wave R1d (t) and the non-Doppler reflected wave R1nd (t), and is represented by the following equation (4).

  Here, it is assumed that the detection target velocity vd of the object other than the target Tgt is zero, that is, the frequency of the non-Doppler reflected wave R1nd (t) is the same as the frequency f1 of the transmission wave T1 (t).

Similarly, the reception wave processing unit 12 derives the same equation (1), (3), and (4) during the period when the transmission wave T2 (t) is being transmitted from the transmission antenna 11, and obtains the following equation ( The reflected wave R2 (t) shown in 5) is received via the receiving antenna 13.

  Here, since the amplitudes of the transmission waves T1 (t) and T2 (t) are both A and the frequencies f1 and f2 are almost the same, the amplitude of the Doppler reflected wave R2d (t) is expressed by the following equation (3). It can be represented by a.

  Referring to FIG. 8 again, low noise amplifier 41 in received wave processing section 12 amplifies reflected waves R1 (t) and R2 (t) received by reception antenna 13 and outputs the amplified waves to mixer 42.

  The mixer 42 performs the following processing while the transmission wave T1 (t) is being transmitted from the transmission unit 1. That is, the mixer 42 multiplies the transmission wave T1 (t) received from the directional coupler 32 in the transmission wave processing unit 10 by the reflected wave R1 (t) received from the low noise amplifier 41. Then, the mixer 42 outputs a difference signal having a frequency component of a difference between the frequency component of the transmission wave T1 (t) and the frequency component of the reflected wave R1 (t) and a sum frequency signal having a frequency component of a sum of both frequency components. Generate.

In the mixer 42, a difference signal B1 (t) generated from the transmission wave T1 (t) and the reflected wave R1 (t) is represented by the following equation (6).

  Here, B1d (t) is a difference signal generated from the transmission wave T1 (t) and the Doppler reflected wave R1d (t). K is the amplitude of the difference signal B1d (t). −4π × f1 × L / c is the delay phase θ1. 2 × f1 × vd / c is the Doppler frequency f1d. D1 is a difference signal generated from the transmission wave T1 (t) and the non-Doppler reflected wave R1nd (t), and the frequency of the non-Doppler reflected wave R1nd (t) is equal to the frequency f1 of the transmission wave T1 (t). Therefore, it is a DC component.

Similarly, the mixer 42 performs the following processing while the transmission wave T2 (t) is being transmitted from the transmission unit 1. That is, the mixer 42 multiplies the transmission wave T2 (t) and the reflected wave R2 (t) to generate a difference signal B2 (t) and a sum frequency signal represented by the following equation (7).

  Here, B2d (t) is a difference signal generated from the transmission wave T1 (t) and the Doppler reflected wave R2d (t). K is the amplitude of the difference signal B2d (t). −4π × f2 × L / c is the delay phase θ2. 2 × f2 × vd / c is the Doppler frequency f2d. D2 is a DC difference signal generated from the transmission wave T2 (t) and the non-Doppler reflected wave R2nd (t).

  The mixer 42 outputs the generated difference signals B1 (t), B2 (t) and the sum frequency signal to the IF amplifier 43.

  The IF amplifier 43 is an amplifier having a large amplification rate from, for example, a low frequency band to an intermediate frequency band, and the difference signal B1 (t), B2 (t) generated in the mixer 42 and the difference signal B1 ( t) and B2 (t) are amplified with a large amplification factor, and the amplified difference signals B1 (t) and B2 (t) are output to the low-pass filter 44.

  The low-pass filter 44 attenuates a component having a frequency equal to or higher than a predetermined frequency, for example, a component having a frequency equal to or higher than 1 kHz, among the frequency components of the difference signals B1 (t) and B2 (t) amplified by the IF amplifier 43.

  The A / D converter 45 performs sampling processing of the difference signals B1 (t) and B2 (t) at a predetermined sampling frequency fsmpl, for example. More specifically, the A / D converter 45 converts the difference signals B1 (t) and B2 (t), which are analog signals that have passed through the low-pass filter 44, into q bits (q / q) for each sampling period (1 / fsmpl). Is an integer of 2 or more). The A / D converter 45 outputs the converted digital signal to the signal processing unit 3.

[Signal processing]
FIG. 10 is a diagram illustrating a configuration of a signal processing unit in the radio wave sensor according to the first embodiment of the present invention. Referring to FIG. 10, signal processing unit 3 includes a buffer control unit 71, a first buffer 72, a second buffer 73, and an FFT processing unit 74.

  The signal processing unit 3 processes a digital signal received from the receiving unit 2. More specifically, the buffer control unit 71 in the signal processing unit 3 converts the digital signal received from the receiving unit 2 into the first buffer 72 and the second buffer 72 based on the level Ls of the switching signal received from the transmitting unit 1 during the transmission period Tt. The data is accumulated while being distributed to the buffer 73.

  Specifically, for example, during a period when the low-level switching signal is being received, that is, when the transmitting unit 1 is transmitting the transmission wave T1 (t) of the frequency f1, the buffer control unit 71 The signals are stored in the first buffer 72 in chronological order. Further, the buffer control unit 71 converts the digital signal received from the receiving unit 2 into a second period while the transmitting unit 1 is transmitting the transmission wave T2 (t) having the frequency f2, for example, during a period when the high-level switching signal is being received. 2 are stored in the buffer 73 in chronological order.

  For example, when the level Ls of the switching signal becomes zero, the buffer control unit 71 recognizes that the transmission period Tt has expired, and ends the accumulation of the digital signal. Then, the buffer control unit 71 outputs a storage completion notification to the FFT processing unit 74, for example.

  Therefore, at the timing when the storage completion notification is output, the first buffer 72 stores the digital signal based on the difference signal B1 (t) during the transmission period Tt, that is, the time spectrum TS1, and the second buffer 73 stores A digital signal based on the difference signal B2 (t) in the transmission period Tt, that is, a time spectrum TS2 is accumulated.

  For example, upon receiving the storage completion notification from the buffer control unit 71, the FFT processing unit 74 creates a Doppler spectrum DS1 and a phase spectrum PS1 by performing a fast Fourier transform on the time spectrum TS1 stored in the first buffer 72. Further, the FFT processing unit 74 creates a Doppler spectrum DS2 and a phase spectrum PS2, for example, by performing a fast Fourier transform on the time spectrum TS2 stored in the second buffer 73.

  The FFT processing unit 74 outputs the created Doppler spectra DS1 and DS2 and the phase spectra PS1 and PS2 to the detection unit 4.

[Detection processing]
FIG. 11 is a diagram illustrating a configuration of a detection unit in the radio wave sensor according to the first embodiment of the present invention. Referring to FIG. 11, detection section 4 includes a spectrum analysis section 76 and an analysis result determination section 77.

  More specifically, the detection unit 4 performs the above-described detection processing for one time based on the radio wave received by the reception unit 2 during the transmission period Tt, for example.

  Specifically, the spectrum analysis unit 76 in the detection unit 4 analyzes the Doppler spectra DS1 and DS2 and the phase spectra PS1 and PS2 received from the FFT processing unit 74, and outputs an analysis result to the analysis result determination unit 77.

More specifically, for example, the spectrum analysis unit 76 searches for one or a plurality of peaks in the Doppler spectrum DS1, and acquires a Doppler frequency f1dmax that is the frequency of the searched peak. The spectrum analysis unit 76 calculates the detection target speed vd of the target Tgt from the acquired Doppler frequency f1dmax using, for example, the following equation (8). The spectrum analysis unit 76 may calculate the detection target speed vd from the Doppler spectrum DS2, for example.

Further, the spectrum analyzer 76 acquires delay phases θ1max and θ2max corresponding to the Doppler frequency f1dmax, respectively, by referring to the phase spectra PS1 and PS2, for example. The spectrum analyzing unit 76 calculates the distance L from the acquired delay phases θ1max and θ2max to the target Tgt using, for example, the following equation (9).

  The spectrum analysis unit 76 outputs, for example, the peak intensity and the detection target speed vd and the distance L corresponding to the peak to the analysis result determination unit 77 as an analysis result.

  The analysis result determination unit 77 detects the target Tgt in the target area based on the analysis result received from the spectrum analysis unit 76. For example, when detecting the target Tgt in the target area, the analysis result determination unit 77 outputs target detection information to the control unit 5 and the signal control device 151. In addition, for example, when the target Tgt in the target area is not detected, the analysis result determination unit 77 outputs target non-detection information to the control unit 5 and the signal control device 151.

[effect]
Referring again to FIGS. 5 and 6, as described above, in the period corresponding to the normal execution interval In of 100 milliseconds, a radio wave having a power of 0 dBm, that is, 1 milliwatt is transmitted for 50 milliseconds, and 4000 milliseconds. In a period corresponding to the second extended execution interval Ie, a radio wave having a power of 6 dBm, that is, about 4 milliwatts is transmitted for 50 milliseconds.

  Therefore, if the ratio of the powers Pce and Pcn supplied by the power supply intermittent unit 80 approximates, for example, 4 which is the ratio of 4 milliwatts and 1 milliwatt, the average power consumption during the period corresponding to the normal execution interval In is (Pcn / 2) ), Whereas the average power consumption in the period corresponding to the extended execution interval Ie is ((4 × Pcn) / 80) milliwatts.

  Here, a value obtained by subtracting ((4 × Pcn) / 80) milliwatts from (Pcn / 2) milliwatts is ((36 × Pcn) / 80) milliwatts. Since Pcn is positive, ((36 × Pcn) / 80) milliwatts has a positive value. In other words, power corresponding to ((36 × Pcn) / 80) milliwatts can be saved on average in a period corresponding to the extended execution interval Ie.

  Further, for example, the average power consumption when the expansion execution interval Ie is 2000 milliseconds is ((4 × Pcn) / 40) milliwatts. Therefore, a value obtained by subtracting ((4 × Pcn) / 40) milliwatts from (Pcn / 2) milliwatts is ((16 × Pcn) / 40) milliwatts. Since Pcn is positive, ((16 × Pcn) / 40) milliwatt has a positive value. That is, even when the expansion execution interval Ie is 2000 milliseconds, power can be saved on average.

  From the above calculation, when the ratio of the powers Pce and Pcn is approximated to 4, the power can be averagely saved in the period corresponding to the enlarged execution interval Ie if the enlarged execution interval Ie is longer than four times the normal execution interval In. I understand.

[Modification 1 of radio wave sensor 101]
FIG. 12 is a diagram showing a configuration of a modified example of the radio wave sensor according to the first embodiment of the present invention.

  Referring to FIG. 12, radio wave sensor 102 which is a modification of radio wave sensor 101 shown in FIG. 2 is different from radio wave sensor 101 in that transmission unit 6 and control unit 7 are used instead of transmission unit 1 and control unit 5. Prepare. The transmitting unit 6 includes a distant transmitting antenna 15 and a normal transmitting antenna 16 instead of the transmitting antenna 11 as compared with the transmitting unit 1 shown in FIG. 2, and further includes an antenna switch 14. Note that the far transmitting antenna 15 and the normal transmitting antenna 16 are not limited to the configuration provided in the radio sensor 102 but may be provided outside the radio sensor 102.

  The operations of the receiving unit 2, the signal processing unit 3, and the detecting unit 4 are the same as those of the receiving unit 2, the signal processing unit 3, and the detecting unit 4 illustrated in FIG. The operation of the transmission wave processing unit 10 in the transmission unit 6 is the same as that of the transmission wave processing unit 10 in the transmission unit 1 shown in FIG. The amplification factor of the power amplifier 33 in the transmission wave processing unit 10 is set to, for example, a fixed value.

  FIG. 13 is a diagram illustrating a configuration of a control unit in a modified example of the radio wave sensor according to the first embodiment of the present invention.

  Referring to FIG. 13, control section 7 includes an antenna switching control section 86 instead of amplification rate control section 81 as compared with control section 5 shown in FIG. 3.

  The operations of the supply power intermittent unit 80, the comprehensive determination unit 82, and the remaining battery level measurement unit 83 in the control unit 7 are described in detail in the description of the operation of the supply power intermittent unit 80, the total determination unit 82, and the remaining battery level measurement unit 83 in the control unit 5 shown in FIG. And respectively.

  FIG. 14 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the first embodiment of the present invention. FIG. 14 shows an operation when the operation mode is switched from the normal detection mode to the enlargement detection mode at, for example, time (t1 + 68) milliseconds, similarly to FIG. The time change of the level Ls of the switching signal shown in FIG. 14 is the same as the time change of the level Ls of the switching signal shown in FIG.

  FIG. 15 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the first embodiment of the present invention. FIG. 15 shows an operation when the operation mode switches from the enlargement detection mode to the normal detection mode at, for example, time (t2 + 125) milliseconds, similarly to FIG. The time change of the level Ls of the switching signal shown in FIG. 15 is the same as the time change of the level Ls of the switching signal shown in FIG.

  12 to 15, normal transmitting antenna 16 has directivity similar to that of transmitting antenna 11 shown in FIG. 2, for example, and the direction of directivity is in the transverse direction of pedestrian crossing PC1. It is set up along. Therefore, the target area when the transmission waves T1 (t) and T2 (t) of the predetermined power are transmitted from the normal transmission antenna 16 is, for example, the normal target area An1 shown in FIGS. 1 and 7.

  Further, the far transmitting antenna 15 has a longer directivity than the normal transmitting antenna 16, for example, by narrowing the beam width and increasing the gain to extend the cover distance, and having a longer directivity in the beam direction. Therefore, the target area when the transmission waves T1 (t) and T2 (t) of the predetermined power are transmitted from the distant transmission antenna 15 is, for example, the expansion target area Ae2 shown in FIG.

  13 supplies power Pc2 to radio wave generation unit 31 and power amplifier 33 in transmission wave processing unit 10 during transmission periods Ttn and Tte, for example, as shown in FIGS. 14 and 15. Since the amplification factor of the power amplifier 33 is a fixed value, the power supplied to the power amplifier 33 in the transmission periods Ttn and Tte is the same, for example.

  The antenna switching control unit 86 changes the range of the target area, for example, according to whether a predetermined condition including a condition regarding a result of the detection processing is satisfied. Specifically, for example, the antenna switching control unit 86 switches the antenna switch 14 in the transmitting unit 6 according to the type of the execution interval, and changes the directivity of the antenna in the transmitting unit 6 to change the range of the target area. In other words, the range of the target area is changed by changing the gain of the antenna in the transmitting unit 6.

  More specifically, for example, as shown in FIGS. 14 and 15, the antenna switching control unit 86 connects the output terminal of the power amplifier 33 and the normal transmission antenna in the transmission period Ttn and the suspension period Thn based on the normal execution interval In. 16 is electrically connected. Therefore, in the transmission period Ttn, the transmission wave processing unit 10 transmits a radio wave to the normal target area An1 via the normal transmission antenna 16.

  Further, for example, as shown in FIGS. 14 and 15, the antenna switching control unit 86 connects the output terminal of the power amplifier 33 to the remote transmission antenna 15 during the transmission period Tte and the suspension period The based on the enlarged execution interval Ie. Make an electrical connection. Therefore, in the transmission period Tte, the transmission wave processing unit 10 transmits a radio wave to the enlargement target area Ae2 via the remote transmission antenna 15.

  Note that the antenna switching control unit 86 is configured to electrically connect the output terminal of the power amplifier 33 and the normal transmission antenna 16 in the transmission period Ttn and the stop period Thn, but is not limited thereto. . The antenna switching control unit 86 only needs to be configured to electrically connect the output terminal of the power amplifier 33 and the normal transmission antenna 16 at least in the transmission period Ttn, for example.

  Further, the antenna switching control unit 86 is configured to electrically connect the output terminal of the power amplifier 33 and the distant transmission antenna 15 in the transmission period Tte and the suspension period The, but the present invention is not limited to this. Absent. The antenna switching control unit 86 only needs to be configured to electrically connect the output terminal of the power amplifier 33 and the distant transmission antenna 15 at least in the transmission period Tte, for example.

[Modification 2 of radio wave sensor 101]
FIG. 16 is a diagram illustrating a configuration of a modified example of the radio wave sensor according to the first embodiment of the present invention.

  Referring to FIG. 16, a radio wave sensor 103 which is a modification of radio wave sensor 101 shown in FIG. 2 is different from radio wave sensor 101 in that transmission unit 8 and control unit 9 are used instead of transmission unit 1 and control unit 5. Prepare. The transmitting section 8 includes a variable tilt transmitting antenna 18 instead of the transmitting antenna 11 as compared with the transmitting section 1 shown in FIG. The variable tilt transmitting antenna 18 is not limited to the configuration provided in the radio wave sensor 103, and may be provided outside the radio wave sensor 103.

  The operations of the receiving unit 2, the signal processing unit 3, and the detecting unit 4 are the same as those of the receiving unit 2, the signal processing unit 3, and the detecting unit 4 illustrated in FIG. The operation of the transmission wave processing unit 10 in the transmission unit 8 is the same as that of the transmission wave processing unit 10 in the transmission unit 1 shown in FIG. The amplification factor of the power amplifier 33 in the transmission wave processing unit 10 is set to, for example, a fixed value.

  FIG. 17 is a diagram illustrating a configuration of a control unit in a modification of the radio wave sensor according to the first embodiment of the present invention.

  Referring to FIG. 17, control unit 9 includes a tilt angle control unit 87 instead of amplification factor control unit 81, as compared with control unit 5 shown in FIG.

  The operations of the power supply intermittent unit 80, the comprehensive determination unit 82, and the remaining battery level measurement unit 83 in the control unit 9 are described in detail in the description of the operation of the power supply intermittent unit 80, the general determination unit 82, and the remaining battery level measurement unit 83 in the control unit 5 shown in FIG. And respectively.

  FIG. 18 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the first embodiment of the present invention. FIG. 18 shows an operation when the operation mode is switched from the normal detection mode to the enlargement detection mode at, for example, time (t1 + 68) milliseconds, as in FIG. The time change of the level Ls of the switching signal shown in FIG. 18 is the same as the time change of the level Ls of the switching signal shown in FIG.

  FIG. 19 is a diagram illustrating an example of a change in an operation mode according to a modified example of the radio wave sensor according to the first embodiment of the present invention. FIG. 19 shows an operation when the operation mode switches from the enlargement detection mode to the normal detection mode at, for example, time (t2 + 125) milliseconds, as in FIG. The time change of the level Ls of the switching signal shown in FIG. 19 is the same as the time change of the level Ls of the switching signal shown in FIG.

  FIG. 20 is a diagram illustrating an example of the direction of the directivity of the tilt-variable transmitting antenna in the modification example of the radio wave sensor according to the first embodiment of the present invention. FIG. 20 shows the tilt angles αn and αe indicating the direction of the tilt variable transmission antenna 18 with respect to the vertically downward direction on a vertical plane including the directivity directions Dn and De of the tilt variable transmission antenna 18.

  Referring to FIGS. 16 to 20, for example, as shown in FIGS. 18 and 19, power supply intermittent unit 80 shown in FIG. 17 includes radio wave generation unit 31 in transmission wave processing unit 10 in transmission periods Ttn and Tte. The power Pc3 is supplied to the power amplifier 33. Since the amplification factor of the power amplifier 33 is a fixed value, the power supplied to the power amplifier 33 in the transmission periods Ttn and Tte is the same.

  The tilt angle control unit 87 changes the range of the target area, for example, according to whether a predetermined condition including a condition regarding the result of the detection processing is satisfied. Specifically, the tilt angle control unit 87 changes the direction of the antenna in the transmission unit 8 by switching the direction of the tilt variable transmission antenna 18 in the transmission unit 8, that is, the tilt angle according to the type of the execution interval. To change the range of the target area.

  Specifically, for example, as shown in FIGS. 18 and 19, the tilt angle control unit 87 sets the tilt angle of the tilt variable transmission antenna 18 to αn in the transmission period Ttn and the stop period Thn based on the normal execution interval In. By setting, the directivity direction Dn is set so as to be directed to the substantially center position Cn of the pedestrian crossing PC1 shown in FIG. 1, FIG. 7, and FIG.

  Therefore, in the transmission period Ttn, the target area when the transmission waves T1 (t) and T2 (t) of the predetermined power are transmitted from the tilt variable transmission antenna 18 with the tilt angle αn is, for example, as shown in FIGS. The normal target area An1 shown in FIG.

  Further, for example, as shown in FIGS. 18 and 19, the tilt angle control unit 87 sets the tilt angle of the tilt variable transmission antenna 18 to αe larger than αn in the transmission period Tte and the stop period Thee based on the enlarged execution interval Ie. By setting, the directivity direction De is set so as to face the following direction. That is, the tilt angle control unit 87 sets the radio wave sensor 103 so that the direction De of the directivity of the transmission wave is along the transverse direction of the pedestrian crossing PC1 and is compared with the position Cn shown in FIGS. Is set so as to face a position Ce away from.

  Therefore, the direction of the tilt variable transmission antenna 18 in the transmission period Tte and the stop period Theh is upward from the direction of the tilt variable transmission antenna 18 in the transmission period Ttn and the stop period Thn. In the transmission period Tte, the target area when the transmission waves T1 (t) and T2 (t) having the predetermined power are transmitted from the tilt variable transmission antenna 18 having the tilt angle αe is, for example, as shown in FIGS. The area to be enlarged Ae1 shown in FIG.

  Note that the tilt angle control unit 87 is configured to set the tilt angle of the tilt variable transmission antenna 18 to αn in the transmission period Ttn and the stop period Thn, but the present invention is not limited to this. The tilt angle control section 87 may have a configuration that sets the tilt angle of the tilt variable transmission antenna 18 to αn at least in the transmission period Ttn, for example.

  Further, the tilt angle control section 87 is configured to set the tilt angle of the tilt variable transmission antenna 18 to αe in the transmission period Tte and the stop period Theh, but the present invention is not limited to this. The tilt angle control section 87 may be configured, for example, to set the tilt angle of the tilt variable transmission antenna 18 to αe in at least the transmission period Tte.

[motion]
FIG. 21 is a flowchart that defines an operation procedure when the radio wave sensor according to the first embodiment of the present invention detects a target in a target area according to an operation mode. The radio wave sensor 101 in the signal control system 201 includes a computer, and an arithmetic processing unit such as a CPU in the computer reads out a program including some or all of the steps of the following flowchart 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.

  Referring to FIG. 21, first, when the operation mode is maintained in the enlargement detection mode (YES in step S102), control unit 5 in radio wave sensor 101 repeatedly performs enlargement detection processing (step S104).

  On the other hand, when the operation mode is maintained in the normal detection mode (NO in step S102), control unit 5 repeatedly performs the normal detection process (step S106).

  FIG. 22 is a flowchart that defines an operation procedure when the radio wave sensor according to the first embodiment of the present invention detects an object in the enlargement target area in the enlargement detection mode. FIG. 22 shows details of the operation of the enlargement detection processing in step S104 of FIG.

  Referring to FIG. 22, first, control unit 5 of radio wave sensor 101 sets an enlargement execution interval Ie (step S202).

  Next, until the transmission period Tte based on the enlargement execution interval Ie set by the control unit 5 expires (NO in step S204), the transmission unit 1 transmits a radio wave to the enlargement target area Ae1 (step S206). The receiving unit 2 receives a radio wave from the expansion target area Ae1 (Step S208).

  On the other hand, when the transmission period Tte expires (YES in step S204), the control unit 5 stops the transmission of electric waves from the transmission unit 1 by stopping the power supply to the transmission unit 1 during the suspension period The ( Step S210).

  Next, the detecting unit 4 performs a detecting process based on the radio wave received by the receiving unit 2 during the transmission period Tte (Step S212).

  Next, as a result of the detection processing, when the target Tgt is not detected (NO in step S214), the control unit 5 continues the power supply to the transmission unit 1 until the stop period The expires, thereby transmitting the transmission. The suspension of the transmission of the radio wave from the unit 1 is continued (step S216).

  Next, when the suspension period The expires, the control unit 5 sets the next enlargement execution interval Ie (Step S202).

  In addition, as a result of the detection processing, when the target Tgt is detected (YES in step S214), the control unit 5 switches from the enlargement detection mode to the normal detection mode (step S218).

  Next, the control unit 5 ends the enlargement detection process and starts the normal detection process by shortening the enlargement execution interval Ie at the timing of switching to the normal detection mode (step S220).

  FIG. 23 is a flowchart that defines an operation procedure when the radio wave sensor according to the first embodiment of the present invention detects an object in the normal target area in the normal detection mode. FIG. 23 shows details of the operation of the normal detection process in step S106 of FIG.

  Referring to FIG. 23, first, control unit 5 in radio wave sensor 101 resets count value Cnt to zero (step S302).

  Next, the control unit 5 sets a normal execution interval In (step S304).

  Next, until the transmission period Ttn based on the normal execution interval In set by the control unit 5 expires (NO in step S306), the transmission unit 1 transmits a radio wave to the normal target area An1 (step S308). The receiving unit 2 receives a radio wave from the normal target area An1 (Step S310).

  On the other hand, when the transmission period Ttn has expired (YES in step S306), the control unit 5 stops the transmission of electric waves from the transmission unit 1 by stopping power supply to the transmission unit 1 in the suspension period Thn (step S306). Step S312).

  Next, the detecting unit 4 performs a detecting process based on the radio wave received by the receiving unit 2 during the transmission period Ttn (Step S314).

  Next, as a result of the detection processing, when the target Tgt is detected (YES in step S316), the control unit 5 resets the count value Cnt to zero (step S318).

  Next, the control unit 5 continues stopping power supply to the transmission unit 1 until the stop period Thn expires, thereby continuing transmission of radio waves from the transmission unit 1 (step S320).

  Next, when the suspension period Thn expires, the control unit 5 sets the next normal execution interval In (Step S304).

  In addition, as a result of the detection processing, when the target Tgt is not detected (NO in step S316), the control unit 5 increments the count value Cnt (step S322).

  Next, when the count value Ctn is smaller than the predetermined threshold value Thc (NO in step S324), the control unit 5 continues stopping power supply to the transmission unit 1 until the stop period Thn expires, The transmission of the radio wave from the transmission unit 1 is stopped (step S320).

  On the other hand, when the count value Ctn is equal to or greater than the predetermined threshold Thc (YES in step S324), the control unit 5 switches from the normal detection mode to the enlargement detection mode (step S326).

  Next, the control unit 5 continues to stop the power supply to the transmission unit 1 until the stop period Thn in the currently executed normal detection process expires, thereby continuing to stop the transmission of the radio wave from the transmission unit 1. When the stop period Thn has expired, the normal detection process ends and the enlargement detection process starts (step S328).

  Note that the radio sensor according to the first embodiment of the present invention is configured to perform control for changing the execution interval of the detection process based on the remaining amount of the battery B1 and the result of the detection process. It is not limited to. The radio wave sensor may be configured to perform control to change the execution interval of the detection process based on the result of the detection process, for example.

  Further, the radio wave sensor according to the first embodiment of the present invention has a configuration in which the suspension period of the power supply to the radio wave generation unit 31 and the power amplifier 33 is changed, but the present invention is not limited to this. The radio wave sensor may be configured to stop supplying power to the reception unit 2, the signal processing unit 3, and the detection unit 4 as a circuit for performing the detection process, for example, after the detection process in the stop period Th is completed. .

  Further, the radio wave sensor according to the first embodiment of the present invention is configured to stop supplying power to the radio wave generation unit 31 and the power amplifier 33 during the stop period Th, but is not limited to this. Absent. The radio wave sensor may be configured to supply power to the radio wave generation unit 31 and the power amplifier 33 during the suspension period Th. This is because, for example, the power consumption in the radio wave generation unit 31 and the power amplifier 33 is larger when the radio wave is transmitted than when the radio wave is stopped. This is because power consumption is suppressed by changing the length of the period.

  Further, the radio wave sensor according to the first embodiment of the present invention is configured to detect the target Tgt in the target area according to the two-frequency CW method. However, the present invention is not limited to this. The radio wave sensor may be configured to detect the target Tgt in the target area according to a method other than the two-frequency CW method. Specifically, the radio wave sensor is, for example, an FM-CW (Frequency-Modulated Continuous-Wave) system described in Non-Patent Document 1 or Non-Patent Document 2, or a two-frequency ICW (Frequency-Modulated Continuous-Wave) system described in Non-Patent Document 3. In accordance with an interrupted continuous-wave (interrupted continuous) method, the configuration may be such that the target Tgt in the target area is detected.

  By the way, for example, when the object identification device described in Patent Document 1 is installed in a place where the power that can be supplied is limited, if the power consumption of the object identification device exceeds the limit value, the object identification device There is a case where it is difficult to operate stably. Therefore, there is a need for a radio wave sensor such as an object identification device that can operate with low power consumption.

  On the other hand, in the radio wave sensor according to the first embodiment of the present invention, the transmission units 1, 6, and 8 transmit radio waves to the target area. The receiving unit 2 receives a radio wave from the target area. The detection unit 4 performs a detection process for detecting the target Tgt in the target area based on the radio waves received by the reception unit 2. The control units 5, 7, and 9 perform control for changing the execution interval of the detection processing based on the result of the detection processing.

  With such a configuration, the frequency of the detection processing can be reduced within a range that does not adversely affect the result of the detection processing, so that the target object can be correctly detected while suppressing power consumption by the detection processing.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the transmission units 1, 6, and 8 continuously transmit radio waves during the transmission period Tt, stop transmission of the radio waves during the stop period Th, and perform transmission. The period Tt and the stop period Th are alternately repeated. The control units 5, 7, and 9 change the execution interval by changing the length of the stop period Th based on the result of the detection processing.

  As described above, with the configuration in which the length of the stop period Th having small power consumption is changed while maintaining the length of the transmission period Tt, power consumption can be suppressed while avoiding deterioration of the accuracy of the detection process. .

  Further, in the radio wave sensor according to the first embodiment of the present invention, the control units 5, 7 and 9 determine whether or not the detection unit 4 has transitioned from a state in which the target Tgt is not detected to a state in which the target Tgt is detected. Is determined, and the execution interval is shortened based on the result of the determination.

  With such a configuration, when the target object Tgt exists in the target area, it is possible to acquire the temporal transition of the detection result of the target object Tgt with high accuracy. In addition, an efficient detection process can be performed by increasing the frequency of the detection process in a situation where a high-frequency detection process is required after the target Tgt is detected.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the control units 5, 7, and 9 determine whether or not the detection unit 4 has transitioned from the state in which the target Tgt is detected to the state in which the target Tgt is not detected. Is determined, and the execution interval is extended based on the result of the determination.

  In this manner, the configuration in which the frequency of the detection processing is reduced in a situation where the high-frequency detection processing after the detection of the target object Tgt is not required is not required, enables efficient detection processing.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the control units 5, 7, and 9 determine the range of the target area in accordance with whether a predetermined condition including a condition regarding a result of the detection processing is satisfied. To change.

  With such a configuration, the range of the target area can be changed to an appropriate range according to the result of the detection processing.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the control unit 5 changes the transmission power of the transmission unit 1 to change the range of the target area.

  With such a configuration, the range of the target area can be changed without using a mechanical operation, so that the mechanism of a transmitting device such as an antenna can be simplified.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the control unit 7 changes the directivity of the antenna in the transmission unit 6. Specifically, the control unit 7 uses the antenna switch 14 to transmit the distant transmission antenna 15. By switching the normal transmission antenna 16, the range of the target area is changed.

  With such a configuration, it is possible to extend the reach of the radio wave without increasing the transmission power of the radio wave, so that an increase in power consumption due to a change in the range of the target area can be suppressed.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the control unit 9 changes the direction of the tilt variable transmission antenna 18 in the transmission unit 8 to change the range of the target area.

  With such a configuration, the beam direction of the radio wave can be changed by a simple method, and the range of the target area can be changed flexibly.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the control units 5, 7, and 9 change the execution interval by changing the suspension period of the power supply to the circuit for performing the detection process. I do.

  As described above, by stopping the circuit for performing the detection processing during the period in which the detection processing is not performed, power consumption can be suppressed while changing the execution interval of the detection processing.

  In the radio wave sensor according to the first embodiment of the present invention, the control units 5, 7, and 9 perform control for changing the execution interval of the detection process based on the remaining amount of the battery B1 and the result of the detection process. Do.

  As described above, with the configuration in which the frequency of the detection process is changed in accordance with the remaining amount of the battery B1, the target object Tgt can be correctly detected while extending the time until the remaining amount of the battery B1 becomes zero. That is, the operation time of the radio wave sensor can be extended.

  Further, in the radio wave sensor according to the first embodiment of the present invention, the control units 5, 7, and 9 make a determination regarding the stop of power supply based on the remaining amount of the battery B1.

  With such a configuration, the power consumption in the circuit can be changed according to the remaining amount of the battery B1, so that the time until the remaining amount of the battery B1 becomes zero can be extended. That is, the operation time of the radio wave sensor can be extended.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

<Second embodiment>
The present embodiment relates to a radio wave sensor that detects an object using a pulse method as compared with the radio wave sensor according to the first embodiment. Except for the content described below, the configuration is the same as that of the radio wave sensor according to the first embodiment.

[Configuration of radio wave sensor]
FIG. 24 is a diagram illustrating a configuration of a radio wave sensor according to the second embodiment of the present invention.

  Referring to FIG. 24, radio wave sensor 104 includes transmitting section 301, receiving section 302, detecting section 304, and control section 5. Transmitting section 301 includes transmitting wave processing section 310 and transmitting antenna 11. Receiving section 302 includes received wave processing section 312 and receiving antenna 13. Note that the transmission antenna 11 and the reception antenna 13 are not limited to the configuration provided in the radio wave sensor 104, and may be provided outside the radio wave sensor 104.

  The operation of the control unit 5 is the same as that of the control unit 5 in the radio wave sensor 101 according to the first embodiment of the present invention shown in FIG. The operation of transmitting antenna 11 in transmitting section 301 is the same as that of transmitting antenna 11 in transmitting section 1 shown in FIG. The operation of receiving antenna 13 in receiving section 302 is the same as that of receiving antenna 13 in receiving section 2 shown in FIG.

  FIG. 25 is a diagram illustrating a configuration of the transmission wave processing unit in the transmission unit according to the second embodiment of the present invention.

  Referring to FIG. 25, transmission wave processing section 310 includes a radio wave generation section 61 and a power amplifier 33. The radio wave generator 61 includes a pulse generator 62, a mixer 63, and a local oscillator 64. The operation of the power amplifier 33 is the same as that of the power amplifier 33 in the transmission wave processing unit 10 shown in FIG.

  24 to 25, radio wave sensor 104 is, for example, a radio wave sensor using a pulse method. More specifically, the control unit 5 of the radio wave sensor 104 changes the transmission interval of the pulse radio wave group, which is a group of pulsed radio waves transmitted by the transmission unit 301, based on the result of the detection processing.

[Execution interval setting]
FIG. 26 is a diagram illustrating an example of a change in the operation mode by the radio wave sensor according to the second embodiment of the present invention. FIG. 26 shows an operation when the operation mode is switched from the normal detection mode to the enlargement detection mode at, for example, time (t3 + 68) milliseconds.

  FIG. 27 is a diagram illustrating an example of a change in the operation mode by the radio wave sensor according to the second embodiment of the present invention. FIG. 27 shows an operation when the operation mode is switched from the enlargement detection mode to the normal detection mode at, for example, time (t4 + 125) milliseconds.

  Referring to FIGS. 26 and 27, mode setting unit 84 in control unit 5 shown in FIG. 4 determines, for example, that the number of times the object non-detection information has been continuously received from detection unit 304 at time (t3 + 68) milliseconds When the predetermined threshold value Thc or more is reached, the operation mode is switched from the normal detection mode to the enlargement detection mode at a time (t3 + 68) milliseconds as shown in FIG.

  When the mode setting unit 84 receives the object detection information from the detection unit 304 at the time (t4 + 125) milliseconds, for example, the operation mode is changed from the expansion detection mode to the normal mode at the time (t4 + 125) milliseconds as shown in FIG. Switch to detection mode.

  The execution interval setting unit 85 sets the execution interval of the detection process, that is, the interval of the pulse group, based on the operation mode and the remaining amount measurement result. Specifically, the execution interval setting unit 85 includes, for example, In the case where the remaining amount measurement result indicates that the amount is small, as shown in FIGS. 26 and 27, the normal execution interval In of 100 ms is set in the normal detection mode, and the enlargement execution of 4000 milliseconds is performed in the enlargement detection mode. Set the interval Ie.

  Further, for example, when the remaining amount measurement result indicates that the remaining battery level is sufficient, the execution interval setting unit 85 sets a normal execution interval In of 100 milliseconds in the normal detection mode, and sets the normal execution interval In in the enlargement detection mode. An extension execution interval Ie of 2000 milliseconds is set.

  Further, as shown in FIG. 26, for example, as shown in FIG. 26, the execution mode is changed from the normal detection mode to the enlargement detection at the time (t3 + 68) milliseconds before the time corresponding to the normal execution interval In elapses from the time t3. The following processing is performed when switching to the mode. That is, the execution interval setting unit 85 newly sets, for example, the enlarged execution interval Ie from the time (t3 + 100) milliseconds at which the time corresponding to the normal execution interval In elapses from the time t3 to the time (t3 + 4100) milliseconds. I do.

  Also, as shown in FIG. 27, for example, as shown in FIG. 27, the execution mode setting unit 85 normally detects the operation mode from the enlargement detection mode at time (t4 + 125) milliseconds before the time corresponding to the enlargement execution interval Ie elapses. The following processing is performed when switching to the mode. That is, the execution interval setting unit 85 shortens the enlarged execution interval Ie at the switching time (t4 + 125) milliseconds to the enlarged execution interval Iei of 125 milliseconds, and starts at the time (t4 + 125) milliseconds at the time (t4 + 225) milliseconds. The normal execution interval In up to seconds is newly set.

[Control of power supply]
For example, as shown in FIG. 26 and FIG. 27, the supply power intermittent unit 80 determines the end timing when the time Δt2 required for transmitting the pulse wave group including three pulse waves elapses from the start timing of the period based on the normal execution interval In. The power Pcn is supplied to the radio wave generator 61 and the power amplifier 33 in the transmission wave processor 310, and the supply of power is stopped from the end timing to the next start timing.

  In addition, for example, as shown in FIG. 26 and FIG. 27, the supply power intermittent unit 80 ends the time Δt2 required for transmitting the pulse radio waves including the three pulse radio waves from the start timing of the period based on the enlarged execution interval Ie. The power Pce is supplied to the radio wave generator 61 and the power amplifier 33 in the transmission wave processor 310 until the timing, and the power supply is stopped from the end timing to the next start timing.

  Therefore, for example, in the case shown in FIG. 26, until the time (t3 + 100) milliseconds, the pulse radio wave group is transmitted from the transmission wave processing unit 310 via the transmission antenna 11 at regular execution intervals In, and the time (t3 + 100) milliseconds After the second, the pulse radio wave group is transmitted at every expansion execution interval Ie.

[Change range of target area]
For example, as shown in FIGS. 26 and 27, the gain control unit 81 sets the gain of the power amplifier 33 to Gn in the period based on the normal execution interval In, and sets the power in the period based on the enlarged execution interval Ie. The amplification factor of the amplifier 33 is set to Ge larger than Gn.

  Therefore, the pulse wave group is transmitted to the enlargement target area Ae1 during the period based on the expansion execution interval Ie, and the pulse wave group is transmitted to the normal target area An1 during the period based on the normal execution interval In.

[Transmission processing of radio waves]
Referring to FIG. 25 again, transmission wave processing section 310 in transmission section 301 repeatedly transmits the pulse wave group via transmission antenna 11. Specifically, the radio wave generation unit 61 in the transmission wave processing unit 310 transmits a pulse radio wave group via the transmission antenna 11 at each execution interval under the control of the control unit 5.

  FIG. 28 is a diagram illustrating an example of a pulse signal generated by the transmission unit and the reception unit according to the second embodiment of the present invention.

  Referring to FIG. 28, pulse generator 62 in radio wave generating section 61 generates, for example, transmission pulse signals Pt1 to Pt3 having level Lpt and time width Δt1 at execution intervals as shown in FIGS. 26 and 27. , And outputs the generated transmission pulse signals Pt1 to Pt3 to the mixer 63. At this time, pulse generator 62 sets, for example, the interval between transmission pulse signals Pt1 and Pt2 and the interval between transmission pulse signals Pt2 and Pt3 to Tp.

  The time width Δt1 is appropriately set according to the distance from the radio wave sensor 104 to the target area, the measurement accuracy of the distance L, and the like. The interval Tp is determined based on, for example, a time required for the transmitted radio wave to be reflected on the target Tgt and returned.

  Local oscillator 64 generates a carrier wave of 24 GHz, for example, and outputs the generated carrier wave to mixer 63. The mixer 63 generates transmission waves Txp1 to Txp3 as a group of pulse waves by multiplying the transmission pulse signals Pt1 to Pt3 received from the pulse generator 62 by the carrier received from the local oscillator 64, and generates the generated transmission wave Txp1. To Txp3 to the power amplifier 33.

  For example, when the amplification factor is set to Gn by the amplification factor controller 81, the power amplifier 33 amplifies the transmission waves Txp1 to Txp3 received from the mixer 63 with the amplification factor Gn, and respectively amplifies the transmission waves Txp1 to Txp3 after amplification. The signal is transmitted to the normal target area An1 via the transmission antenna 11. Further, for example, when the amplification factor is set to Ge by the amplification factor controller 81, the power amplifier 33 amplifies the transmission waves Txp1 to Txp3 received from the mixer 63 with the amplification factor Ge, and transmits the amplified transmission waves Txp1 to Txp3. Are transmitted to the enlargement target area Ae1 via the transmission antennas 11, respectively.

[Electric wave reception processing]
Referring to FIG. 24 again, receiving section 302 receives radio waves from the target area. More specifically, the receiving antenna 13 in the receiving unit 302 receives a group of pulsed radio waves, that is, reflected waves Rxp1 to Rxp3 generated by the target Tgt in the target area reflecting the transmission waves Txp1 to Txp3, respectively.

  FIG. 29 is a diagram illustrating a configuration of a reception wave processing unit in the reception unit according to the second embodiment of the present invention.

  Referring to FIG. 29, received wave processing section 312 includes a low noise amplifier 41, a mixer 42, an IF amplifier 43, a local oscillator 46, and a detector 47. The operations of the low noise amplifier 41, the mixer 42, and the IF amplifier 43 in the reception wave processing unit 312 are the same as those of the low noise amplifier 41, the mixer 42, and the IF amplifier 43 in the reception wave processing unit 12 shown in FIG.

  The low noise amplifier 41 in the reception wave processing unit 312 amplifies the reflected waves Rxp1 to Rxp3 received by the reception antenna 13 and outputs the amplified waves to the mixer 42.

  Local oscillator 46 generates a local signal of, for example, 24 GHz, and outputs the generated local signal to mixer 42. The mixer 42 multiplies the reflected waves Rxp1 to Rxp3 received from the low-noise amplifier 41 by the local signal received from the local oscillator 46, thereby obtaining the frequency component of the difference between the frequency component of the local signal and the frequency components of the reflected waves Rxp1 to Rxp3. And a sum frequency signal having a frequency component of the sum of the difference signal and the two frequency components.

  The IF amplifier 43 amplifies the difference signal of the difference signal and the sum frequency signal generated by the mixer 42 with a large amplification factor, and outputs the amplified difference signal to the detector 47.

  The detector 47 detects the difference signal received from the IF amplifier 43 to generate the reception pulse signals Pr1 to Pr3 shown in FIG. 28 and outputs the generated reception pulse signals Pr1 to Pr3 to the detection unit 304.

[Detection processing]
FIG. 30 is a diagram illustrating a configuration of a detection unit in a radio wave sensor according to the second embodiment of the present invention.

  Referring to FIG. 30, detection section 304 includes a time comparison section 51, an intensity acquisition section 52, a distance calculation section 53, and a measurement result determination section 54.

  The detection unit 304 performs a detection process for detecting the target Tgt in the target area based on the radio waves received by the reception unit 302. More specifically, the detection unit 304 performs the detection processing based on, for example, the reflected waves Rxp1 to Rxp3 from the target area, which are received by the reception unit 302.

  Specifically, the intensity acquisition unit 52 in the detection unit 304 acquires, for example, the levels Lpr1 to Lpr3 of the reception pulse signals Pr1 to Pr3 received from the detector 47 in the reception wave processing unit 312, that is, the intensity, and acquires the acquired intensity. Is output to the measurement result determination unit 54.

  After receiving the transmission pulse signals Pt1 to Pt3 from the transmission unit 301, the time comparison unit 51 calculates time differences β1 to β3 required to receive the reception pulse signals Pr1 to Pr3 from the detector 47, respectively, and calculates the calculated time differences β1 to β3. β3 is output to the distance calculation unit 53.

  The distance calculation unit 53 calculates the distance L based on the time differences β1 to β3 received from the time comparison unit 51. Specifically, distance calculating section 53 calculates, for example, the average of c × β1 / 2, c × β2 / 2 and c × β3 / 2 as distance L, and outputs the calculation result to measurement result determination section 54. .

  The measurement result determination unit 54 detects the target Tgt in the target area based on the intensity received from the intensity acquisition unit 52 and the distance L received from the distance calculation unit 53.

  For example, upon detecting the target Tgt in the target area, the measurement result determination unit 54 outputs the target detection information to the control unit 5 and the signal control device 151. In addition, for example, when the target Tgt in the target area is not detected, the measurement result determination unit 54 outputs target non-detection information to the control unit 5 and the signal control device 151.

  Note that the detection unit 304 acquires the moving speed of the target Tgt based on, for example, a temporal change in the distance L, and detects the target Tgt in the target area based on the obtained moving speed and the intensity and the distance L. You may.

  The transmitting unit according to the second embodiment of the present invention has a configuration in which a pulse radio wave group including three pulse radio waves is repeatedly transmitted, but the present invention is not limited to this. The transmission unit may be configured to repeatedly transmit one pulse radio wave, or may be configured to repeatedly transmit a pulse radio wave group including two or four or more pulse radio waves.

[Modification 1 of radio wave sensor 104]
FIG. 31 is a diagram illustrating a configuration of a modification of the radio wave sensor according to the second embodiment of the present invention.

  Referring to FIG. 31, radio wave sensor 105 which is a modification of radio wave sensor 104 shown in FIG. 24 is different from radio wave sensor 104 in that transmission unit 306 and control unit 7 are replaced with transmission unit 301 and control unit 5. Prepare.

  Transmitting section 306 is different from transmitting section 301 shown in FIG. 24 in that transmitting antenna 11 is replaced with transmitting antenna 15 for the distant place and transmitting antenna 16 for the normal use, and further includes antenna switch 14. Note that the far transmitting antenna 15 and the normal transmitting antenna 16 are not limited to the configuration provided in the radio wave sensor 105, and may be provided outside the radio wave sensor 105.

  The operations of the receiving unit 302 and the detecting unit 304 are the same as those of the receiving unit 302 and the detecting unit 304 shown in FIG. The operation of the control unit 7 is the same as that of the control unit 7 in the radio wave sensor 102 shown in FIG.

  The operations of the antenna switch 14, the distant transmitting antenna 15 and the normal transmitting antenna 16 in the transmitting unit 306 are the same as those of the antenna switch 14, the distant transmitting antenna 15 and the normal transmitting antenna 16 in the transmitting unit 6 shown in FIG. is there. The operation of transmission wave processing section 310 in transmission section 306 is the same as that of transmission wave processing section 310 in transmission section 301 shown in FIG. The amplification factor of power amplifier 33 in transmission wave processing section 310 is set to, for example, a fixed value.

  FIG. 32 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the second embodiment of the present invention. FIG. 32 shows an operation when the operation mode is switched from the normal detection mode to the enlargement detection mode at, for example, time (t3 + 68) milliseconds, similarly to FIG. The time change of the level Lp of the transmission pulse signal shown in FIG. 32 is the same as the time change of the level Lp of the transmission pulse signal shown in FIG.

  FIG. 33 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the second embodiment of the present invention. FIG. 33 shows an operation when the operation mode switches from the enlargement detection mode to the normal detection mode at, for example, time (t4 + 125) milliseconds, similarly to FIG. The time change of the level Lp of the transmission pulse signal shown in FIG. 33 is the same as the time change of the level Lp of the transmission pulse signal shown in FIG.

  Referring to FIGS. 31 to 33, antenna switching control unit 86 in control unit 7 shown in FIG. 13 switches, for example, antenna switch 14 in transmitting unit 306 according to the type of the execution interval. The range of the target area is changed by changing the directivity.

  More specifically, for example, as shown in FIGS. 32 and 33, the antenna switching control unit 86 connects the output terminal of the power amplifier 33 in the transmission wave processing unit 310 and the normal transmission antenna in a period based on the normal execution interval In. 16 is electrically connected. Therefore, in this period, for example, a pulse radio wave group having a predetermined power is transmitted from the normal transmission antenna 16 to the normal target area An1 shown in FIGS. 1 and 7.

  In addition, the antenna switching control unit 86 electrically connects the output terminal of the power amplifier 33 and the distant transmission antenna 15 during a period based on the enlarged execution interval Ie, for example, as shown in FIGS. Therefore, in this period, for example, the pulsed radio wave group of the predetermined power is transmitted from the remote transmitting antenna 15 to the enlargement target area Ae2 shown in FIG.

[Modification 2 of radio wave sensor 104]
FIG. 34 is a diagram illustrating a configuration of a modified example of the radio wave sensor according to the second embodiment of the present invention.

  Referring to FIG. 34, a radio wave sensor 106 which is a modification of radio wave sensor 104 shown in FIG. 24 is different from radio wave sensor 104 in that transmission unit 308 and control unit 9 are used instead of transmission unit 301 and control unit 5. Prepare.

  Transmitting section 308 includes variable tilt transmitting antenna 18 instead of transmitting antenna 11 as compared to transmitting section 301 shown in FIG. The variable tilt transmission antenna 18 is not limited to the configuration provided in the radio wave sensor 106, and may be provided outside the radio wave sensor 106.

  The operations of the receiving unit 302 and the detecting unit 304 are the same as those of the receiving unit 302 and the detecting unit 304 shown in FIG. The operation of the control unit 9 is the same as that of the control unit 9 in the radio wave sensor 103 shown in FIG.

  The operation of variable tilt transmitting antenna 18 in transmitting section 308 is the same as that of variable tilt transmitting antenna 18 in transmitting section 8 shown in FIG. The operation of transmission wave processing section 310 in transmission section 308 is the same as that of transmission wave processing section 310 in transmission section 301 shown in FIG. The amplification factor of power amplifier 33 in transmission wave processing section 310 is set to, for example, a fixed value.

  FIG. 35 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the second embodiment of the present invention. FIG. 35 shows an operation when the operation mode is switched from the normal detection mode to the enlargement detection mode at, for example, a time (t3 + 68) milliseconds, similarly to FIG. The time change of the level Lp of the transmission pulse signal shown in FIG. 35 is the same as the time change of the level Lp of the transmission pulse signal shown in FIG.

  FIG. 36 is a diagram illustrating an example of a change in an operation mode according to a modification of the radio wave sensor according to the second embodiment of the present invention. FIG. 36 shows the operation when the operation mode switches from the enlargement detection mode to the normal detection mode at, for example, time (t4 + 125) milliseconds, similarly to FIG. The time change of the level Lp of the transmission pulse signal shown in FIG. 36 is the same as the time change of the level Lp of the transmission pulse signal shown in FIG.

  Referring to FIGS. 34 to 36, tilt angle control section 87 in control section 9 shown in FIG. 17 switches, for example, the tilt angle of tilt variable transmission antenna 18 in transmitting section 308 in accordance with the type of the execution interval, and performs transmission. By changing the direction of the antenna in the unit 308, the range of the target area is changed.

  Specifically, for example, as shown in FIGS. 35 and 36, the tilt angle control unit 87 sets the tilt angle of the tilt variable transmission antenna 18 to αn in a period based on the normal execution interval In, thereby The sex direction Dn is set so as to face a substantially central position Cn of the crosswalk PC1 shown in FIGS. 1, 7, and 20.

  Therefore, during this period, for example, a pulse radio wave group having a predetermined power is transmitted from the tilt variable transmission antenna 18 having the tilt angle αn to the normal target area An1 shown in FIGS.

  Further, for example, as shown in FIGS. 35 and 36, the tilt angle control unit 87 sets the tilt angle of the tilt variable transmission antenna 18 to αe in a period based on the enlargement execution interval Ie, so that the De is set so as to face the position Ce shown in FIGS. 1, 7, and 20.

  Therefore, in this period, for example, the pulse electric wave group of the predetermined power is transmitted from the tilt variable transmitting antenna 18 having the tilt angle αe to the enlargement target area Ae1 shown in FIGS.

  As described above, in the radio wave sensor according to the second embodiment of the present invention, the transmission units 301, 306, and 308 repeatedly transmit pulse radio waves that are pulse-shaped radio waves. The control units 5, 7, and 9 change the execution interval by changing the transmission interval of the pulse radio wave based on the result of the detection processing.

  As described above, by changing the transmission interval of the repeatedly transmitted pulse radio waves in accordance with the result of the detection processing, it is possible to suppress power consumption while avoiding deterioration in the accuracy of the detection processing.

  It should be noted that some or all of the components and operations of each device according to the first and second embodiments of the present invention can be appropriately combined.

  The above embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The above description includes the features described below.

[Appendix 1]
A transmitter for transmitting radio waves to the target area;
A receiving unit that receives radio waves from the target area,
Based on the radio wave received by the receiving unit, a detection unit that performs a detection process for detecting an object in the target area,
A control unit that performs control to change an execution interval of the detection processing based on a result of the detection processing,
The transmitting unit transmits a radio wave to the target area according to a two-frequency CW method or a pulse method,
The target area is a crosswalk,
The object is a pedestrian,
The radio wave sensor, wherein the control unit switches between a normal execution interval and an enlarged execution interval longer than the normal execution interval based on a result of the detection processing.

1, 6, 8, 301, 306, 308 Transmitting unit 2, 302 Receiving unit 3 Signal processing unit 4, 304 Detecting unit 5, 7, 9 Control unit 10, 310 Transmitting wave processing unit 11 Transmitting antenna 12, 312 Receiving wave processing Unit 13 receiving antenna 14 antenna switch 15 distant transmitting antenna 16 normal transmitting antenna 18 tilt variable transmitting antenna 31 radio wave generating unit 32 directional coupler 33 power amplifier 35 frequency switching unit 36 voltage generating unit 37 voltage controlled oscillator 41 low noise amplifier 42 Mixer 43 IF amplifier 44 Low-pass filter 45 A / D converter 46 Local oscillator 47 Detector 51 Time comparison unit 52 Intensity acquisition unit 53 Distance calculation unit 54 Measurement result judgment unit 61 Radio wave generation unit 62 Pulse generator 63 Mixer 64 Local oscillator 71 Buffer Control unit 72 Buffer 73 Second buffer 74 FFT processing unit 76 Spectrum analysis unit 77 Analysis result determination unit 80 Supply power intermittent unit 81 Amplification rate control unit 82 Total determination unit 83 Battery level measurement unit 84 Mode setting unit 85 Execution interval setting unit 86 Antenna switching Control unit 87 Tilt angle control unit 101, 102, 103, 104, 105, 106 Radio wave sensor 121 Power generation unit 151 Signal control device 161 Pedestrian signal light 201 Signal control system B1 Battery

Claims (6)

A transmitter for transmitting radio waves to the target area;
A receiving unit that receives radio waves from the target area,
Based on the radio wave received by the receiving unit, a detection unit that performs a detection process for detecting an object in the target area,
A control unit that performs control to change an execution interval of the detection processing,
With a battery,
The radio wave sensor, wherein the control unit performs control to change an execution interval of the detection process based on a remaining amount of the battery . A radio wave sensor,
A transmitter for transmitting radio waves to the target area;
A receiving unit that receives radio waves from the target area,
Based on the radio wave received by the receiving unit, a detection unit that performs a detection process for detecting an object in the target area,
A control unit that performs control to change the execution interval of the detection process,
The control unit changes the execution interval by changing a suspension period of power supply to a circuit for performing the detection process,
The radio wave sensor further includes:
Equipped with a battery,
The radio wave sensor, wherein the control unit makes a determination regarding the stop of the power supply based on a remaining amount of the battery. A detection method in a radio wave sensor,
Transmitting radio waves to the target area;
Receiving radio waves from the target area,
Based on the received radio waves, performing a detection process for detecting an object in the target area,
And a step of performing control to change the interval of pre-Symbol detection process,
The radio wave sensor includes a battery,
A detection method, wherein in the step of performing the control, control is performed to change an execution interval of the detection process based on the remaining amount of the battery. A detection method in a radio wave sensor,
Transmitting radio waves to the target area;
Receiving radio waves from the target area,
Based on the received radio waves, performing a detection process for detecting an object in the target area,
Performing a control to change the execution interval of the detection process,
In the step of performing the control, by changing the suspension period of power supply to the circuit for performing the detection process, to change the execution interval,
The radio wave sensor includes a battery,
A detection method, wherein in the step of performing the control, a determination regarding the stop of the power supply is performed based on a remaining amount of the battery. A detection program used in a radio wave sensor that transmits a radio wave to a target area and receives a radio wave from the target area,
On the computer,
Based on the received radio waves, performing a detection process for detecting an object in the target area,
A program for and a step of performing control to change the interval of pre-Symbol detection process,
The radio wave sensor includes a battery,
In the detection program, in the step of performing the control, control is performed to change an execution interval of the detection process based on the remaining amount of the battery. A detection program used in a radio wave sensor that transmits a radio wave to a target area and receives a radio wave from the target area,
On the computer,
Based on the received radio waves, performing a detection process for detecting an object in the target area,
And performing a control to change the execution interval of the detection process,
In the step of performing the control, by changing the suspension period of power supply to the circuit for performing the detection process, to change the execution interval,
The radio wave sensor includes a battery,
In the step of performing the control, a detection program for performing a determination regarding the stop of the power supply based on a remaining amount of the battery.

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