JP7306213B2 - RADIO SENSOR, CONTROL METHOD FOR RADIO SENSOR, AND COMPUTER PROGRAM - Google Patents

Description

The present disclosure relates to radio wave sensors, radio wave sensor control methods, and computer programs.

Patent Literature 1 discloses a radio wave sensor that detects an object by reflecting transmitted radio waves. Further, Patent Literature 1 discloses suppressing power consumption by changing the execution interval of object detection processing based on the remaining battery level.

JP 2015-224936 A

By adjusting the power consumption of the radio wave sensor according to the remaining battery power, it becomes easier to avoid stopping the operation of the radio wave sensor due to power failure. However, even if the current battery level is high, it may be preferable to reduce the power consumption if the expected future charge amount is low. Also, even if the current battery level is low, it may not be necessary to reduce the power consumption if the expected future charge amount is large. Therefore, it may not be possible to appropriately adjust the power consumption based on the current remaining battery power.

Therefore, it is desired to more appropriately adjust the power consumption of the radio wave sensor.

One aspect of the present disclosure is a radio wave sensor. The disclosed radio wave sensor detects an object by reflecting transmitted radio waves. The radio sensor includes a controller that adjusts the power consumption of the radio sensor based on the future remaining battery capacity of a battery that is charged by a power generator and supplies power to the radio sensor.

Another aspect of the present disclosure is a control method. The disclosed control method relates to a radio wave sensor that detects an object by reflecting transmitted radio waves. The control method includes adjusting the power consumption of the radio wave sensor based on a future remaining battery capacity of a battery charged by a power generator and supplying power to the radio wave sensor.

Another aspect of the disclosure is a computer program product. The disclosed computer program causes a computer to operate as a controller of a radio wave sensor that detects an object by reflecting transmitted radio waves. The controller adjusts the power consumption of the radio wave sensor based on the future remaining battery capacity of a battery that is charged by a power generator and supplies power to the radio wave sensor.

According to the present disclosure, it is possible to more appropriately adjust the power consumption of the radio wave sensor based on the future remaining battery level.

FIG. 1 is a perspective view of a road on which radio wave sensors are installed. FIG. 2 is a block diagram of the radio wave sensor. FIG. 3 is a hardware configuration diagram of the controller. FIG. 4 is a flowchart of power consumption adjustment processing. FIG. 5 is a controller-related diagram. FIG. 6 is a diagram illustrating reduction in chirp time. FIG. 7 is a diagram illustrating the reduction in chirp time. FIG. 8 is a flowchart of power consumption adjustment processing.

[Description of Embodiments of the Present Disclosure]

(1) A radio wave sensor according to an embodiment detects an object by reflecting transmitted radio waves. The radio sensor includes a controller that adjusts the power consumption of the radio sensor based on the future remaining battery capacity of a battery that is charged by a power generator and supplies power to the radio sensor. By adjusting the power consumption based on the remaining battery capacity in the future, the power consumption will be appropriate for the future situation.

(2) Preferably, the controller is configured to estimate a future amount of charge for the battery, and the future remaining battery capacity is calculated based on the future amount of charge. In this case, the future remaining battery capacity is calculated from the future charge amount.

(3) Preferably, the controller estimates the future charge amount based on data affecting the future remaining battery capacity. In this case, the future remaining battery capacity can be easily estimated based on the data that affects the future remaining battery capacity.

(4) Preferably, the data affecting the future remaining battery capacity includes weather forecast data. It is possible to estimate the remaining battery capacity by considering fluctuations in power generation due to weather.

(5) Preferably, the controller adjusts transmission parameters of the radio waves to adjust the power consumption. Since transmission parameters affect power consumption, power consumption can be adjusted by adjusting transmission parameters.

(6) Preferably, the controller adjusts communication parameters with an external device to adjust the power consumption. Since communication parameters with external devices affect power consumption, power consumption can be adjusted by adjusting communication parameters.

(7) The radio wave sensor is preferably for traffic monitoring. Preferably, the controller adjusts the power consumption further based on traffic information around the radio wave sensor. In this case, power consumption can be appropriately adjusted according to traffic conditions.

(8) The traffic information may include vehicle detection results obtained by the radio wave sensor. In this case, power consumption can be adjusted using the detection result of the radio wave sensor itself.

(9) The traffic information may include vehicle detection results obtained by sensors other than the radio wave sensor. In this case, power consumption can be adjusted using detection results obtained from other sensors. By using detection results from other sensors, it is possible to estimate future traffic conditions in the detection area of the radio wave sensor itself and adjust power consumption appropriately.

(10) The controller can select, according to the traffic information, the radio wave transmission parameters to be adjusted for adjusting the power consumption. By varying the transmission parameters to be adjusted according to the traffic conditions, power consumption can be made appropriate according to the traffic conditions.

(11) When adjusting the power consumption to lower, the controller preferably adjusts the power consumption according to the speed of the vehicle around the radio wave sensor. In this case, power consumption can be appropriately adjusted according to the speed of the vehicle.

(12) Preferably, the radio wave is transmitted as a chirp signal whose frequency changes with time, and the adjustment of the power consumption includes adjusting the chirp signal. Power consumption can be adjusted by adjusting the chirp signal.

(13) Adjusting the chirp signal may include adjusting a chirp time. For example, depending on the speed of the vehicle, the chirp time can be shortened. As an example, the chirp time can be shortened if the speed is less than or greater than the predetermined speed. A shorter chirp time can increase the maximum detection speed. Therefore, shortening the chirp time is advantageous when it is desired to detect a high-speed vehicle while suppressing power consumption.

(14) Adjusting the chirp signal may include adjusting a number of chirps. Even if the number of chirps is reduced, the range resolution and maximum detectable range can be maintained. Therefore, reducing the number of chirps is advantageous when it is desired to secure the distance resolution and the maximum detection distance while suppressing power consumption.

(15) The controller can adjust the power consumption according to the number of vehicles around the radio wave sensor when adjusting the power consumption to decrease. In this case, power consumption can be appropriately adjusted according to the number of vehicles.

(16) It is preferable that the controller transmits, to the outside of the radio wave sensor, notification data indicating a change in performance of the radio wave sensor due to the adjustment of the power consumption. In this case, it is possible to inform the outside of the radio wave sensor of changes in the performance of the radio wave sensor.

(17) Preferably, the notification data includes data indicating how the performance of the radio wave sensor has changed. In this case, it is possible to inform the outside of the radio wave sensor how the performance of the radio wave sensor has changed.

(18) A control method according to an embodiment is a control method for a radio wave sensor that detects an object by reflection of transmitted radio waves. The control method includes adjusting the power consumption of the radio wave sensor based on a future remaining battery capacity of a battery charged by a power generator and supplying power to the radio wave sensor.

(19) A computer program according to an embodiment causes a computer to operate as a controller of a radio wave sensor that detects an object by reflecting transmitted radio waves. The controller adjusts the power consumption of the radio wave sensor based on the future remaining battery capacity of a battery that is charged by a power generator and supplies power to the radio wave sensor. A computer program is stored in a computer-readable, non-transitory storage medium.

[Details of the embodiment of the present disclosure]

FIG. 1 shows a road 110 on which a radio wave sensor 200 according to the embodiment is installed. The radio wave sensor 200 detects an object by reflecting the transmitted radio waves. The radio wave sensor 200 of the embodiment is configured as a millimeter wave radar sensor and used for traffic monitoring. The radio wave sensor 200 detects the vehicle 11 existing within a detection area 201 set on the road 110 .

As shown in FIG. 2, the radio wave sensor 200 includes a transmitter 331 that transmits radio waves for object detection. In an embodiment, the signal transmitted as radio waves from transmitter 331 is a Chirp signal. A chirp signal is a signal whose frequency varies with time. The chirp signal will be described later.

The radio wave sensor 200 includes a receiver 332 that receives reflected waves of the transmitted radio waves. The receiver 332 outputs a received signal of the reflected wave.

The radio wave sensor 200 includes a digital signal processor (DSP) 333 and a CPU 334 . The DSP 333 performs signal processing on the received signal of the reflected wave, and generates detection data such as the position, speed and angle of an object such as a vehicle.

The CPU 334 executes correction processing of the detection data as necessary. In the correction process, for example, parallel running vehicles are separated. Correction processing such as separation of parallel running vehicles is performed by, for example, a Kalman filter.

The radio wave sensor 200 includes a controller 310 for adjusting power consumption of the radio wave sensor 200 and the like. Note that the functions of the controller 310 may be performed by the CPU 334 . Adjustment of power consumption by the controller 310 will be described later.

The radio wave sensor 200 includes a communication device 340 for communicating with an external device. Communicator 340 is for wireless or wired communication. The radio wave sensor 200 can transmit and receive data to and from an external device via the communication device 340 . The external device may be, for example, a server on a network, another radio wave sensor, a roadside sensor other than the radio wave sensor, or a device connected to the radio wave sensor 200 .

The radio wave sensor 200 includes a battery 400 that supplies power for the operation of the radio wave sensor 200 . The battery 400 is connected to a power generator 500 such as a solar power generator. The power generation device 500 is not limited to a solar power generation device, and may be another type of power generation device that generates power using natural energy, such as a wind power generation device. Note that the battery 400 may be charged from a commercial power supply if possible.

Battery 400 includes a battery meter 410 that monitors the state of the battery. The battery measuring device 410 can measure the charge/discharge amount of the battery 400 and obtain the remaining battery capacity. The battery measuring device 410 outputs the charge amount (actual charge amount) and the current remaining battery capacity SoC _p to the controller 310 . Battery measuring device 410 may output the amount of discharge (actual amount of discharge) to controller 310 .

As described above, the radio wave sensor 200 according to the embodiment is battery-driven and does not require a commercial power supply for operation. Therefore, the radio wave sensor 200 according to the embodiment can be installed in a place where commercial power supplied from a commercial power source cannot be obtained or where it is difficult to obtain it stably.

The controller 310 adjusts the power consumption of the radio wave sensor 200 to prevent the power of the radio wave sensor 200, which is battery-driven, from running out. By changing the operation method of the radio wave sensor 200, that is, the operation mode, according to the situation, it is possible to suppress power consumption and suppress power failure.

As shown in FIG. 3, the controller 310 is composed of a computer having a processor 311 and a storage device 312 . Storage device 312 is connected to processor 311 . A computer program 330 for operating a computer as the controller 310 is stored in the storage device 312 . Processor 311 reads and executes computer program 330 stored in storage device 312 . Computer program 330 has program code for power consumption adjustment processing 350 executed by processor 311 .

FIG. 4 shows the procedure of power consumption adjustment processing 350 executed by the controller 310 . In step S11, the controller 310 estimates the future charge amount _Cf to the battery 440. FIG. In step S12, the controller 310 calculates the future remaining battery capacity SoC _f based on the future charge amount C _f . When the controller 310 determines that the remaining battery level SoCf will decrease in the future, the controller 310 reduces power consumption (steps S13 to S18). Since the performance of radio wave sensor 200 may change due to lower power consumption, controller 310 transmits notification data for notifying the performance change to the outside (step S19).

In step S11, the specific future point in time at which the charge amount _Cf is estimated is appropriately set according to the battery capacity and the like. A specific time in the future is set, for example, several hours or days after the current time.

The future charge amount _Cf is estimated by calculation based on the charge amount estimation data. The charge amount estimation data is data that affects the future charge amount _Cf , and is, for example, weather forecast data. If the power generation amount of the power generation device 500 is affected by the weather like a solar power generation device, the weather forecast data is data that affects the future power generation amount, that is, the future charging amount. The amount of charge _Cf differs depending on whether the weather up to the future time is fine or rainy.

As shown in FIG. 5, weather forecast data is provided by a weather information server 700, for example. Weather information server 700 provides weather forecast data to controller 310 via the network. The weather forecast data includes at least a weather forecast up to a future point in time when the charge amount _Cf is estimated.

In step S11, the controller 310 estimates the future charge amount _Cf based on the weather forecast data. The controller 310 estimates the charge amount _Cf by referring to the charge amount estimation table 320, for example. When the charge amount estimation table 320 defines the relationship between the weather and the charge amount, the controller 310 can refer to the charge amount estimation table 320 to acquire the charge amount corresponding to the weather forecast data. The obtained charge amount becomes an estimated value of the future charge amount _Cf.

The charge amount estimation data is not limited to the weather forecast data, and may be the past actual charge amount of the battery 400 . The past actual charge amount also affects the future charge amount _Cf. The controller 310 acquires the past actual charge amount from the battery measuring device 410 . If the charge amount does not change abruptly, the most recent actual charge amount is useful for estimating the charge amount _Cf in the near future. Also, the future charge amount _Cf can be estimated from the matching between the long-term past actual charge amount pattern and the latest actual charge amount pattern.

For example, when the charge amount estimation table 320 has long-term past actual charge amount patterns, a pattern that matches the most recent actual charge amount pattern is detected in the actual charge amount patterns of the charge amount estimation table 320 . In this case, the future charge amount _Cf is estimated based on the charge amount pattern following the matching pattern in the actual charge amount pattern of the charge amount estimation table 320 .

The charge amount estimation data may be time information. Time information may include date and time information. The amount of charge is affected by whether the time is daytime or nighttime, and by the season in which the day belongs. That is, the time information is data that affects the future charge amount _Cf.

Controller 310 acquires time information from timer 630 . The timer 630 may be included in the radio wave sensor 200 or may be provided outside the radio wave sensor 200 .

The controller 310 can also estimate the future charge amount _Cf based on the time information. When the charge amount estimation table 320 defines the relationship between the time and the charge amount, the controller 310 can refer to the charge amount estimation table 320 to acquire the charge amount corresponding to the time information. The obtained charge amount becomes an estimated value of the future charge amount _Cf.

The charge amount estimation data may be at least one of illuminance and temperature. The amount of charge is affected by illuminance or temperature. In other words, the illuminance and temperature are data that affect the future charge amount _Cf.

Controller 310 acquires illuminance from illuminance meter 610 and acquires temperature from thermometer 620 . The illuminance meter 610 and the thermometer 620 may be provided in the radio wave sensor 200 or may be provided outside the radio wave sensor 200 .

The controller 310 can also estimate the future charge amount _Cf based on at least one of illumination intensity and temperature. When the charge amount estimation table 320 defines the relationship between at least one of the illuminance and temperature and the charge amount, the controller 310 refers to the charge amount estimation table 320 to determine the charge amount corresponding to the illuminance or temperature. can be obtained. The obtained charge amount becomes an estimated value of the future charge amount _Cf.

When estimating the future charge amount _Cf , the above-described data for charge amount estimation may be used in combination. Estimation accuracy can be improved by using a plurality of types of charge amount estimation data.

Further, in the above example, the method of referring to the charge amount estimation table 320 is used to calculate the future charge amount _Cf from the charge amount estimation data, but the present invention is not limited to this. For example, the future charge amount _Cf may be obtained from the charge amount estimation data using a charge amount estimation model in which the relationship between the charge amount estimation data and the charge amount is machine-learned.

When the future charge amount _Cf is obtained as described above, the controller 310 calculates the future remaining battery capacity _SoCf in step S12. The future remaining battery capacity SoC _f can be calculated from, for example, the current remaining battery capacity SoC _p , the current power consumption (actual discharge amount of the battery 400), and the future charge amount C _f . The current remaining battery capacity SoC _p and current power consumption (actual discharge amount of battery 400 ) are obtained from battery measuring device 410 .

In the above example, the _future charge amount _Cf is calculated _and then the future battery charge amount SoC _f is obtained. you may ask. For example, the various data (weather forecast data, etc.) exemplified as the above-described charge amount estimation data (weather forecast data, etc.) also affect the remaining battery capacity in the future. forecast data, etc.) can be used as data for estimating the remaining battery capacity in the future. By preparing a battery remaining amount estimation table that defines the relationship between the estimation data and the remaining battery amount, or a battery remaining amount estimation model that machine-learned the relationship between the estimation data and the remaining battery amount, the controller 310 can estimate the remaining battery capacity from the data for estimating the remaining battery capacity.

When the future remaining battery capacity SoC _f is obtained, the controller 310 makes a determination in step S13 to determine whether power consumption adjustment is necessary. The determination in step S13 is made based on the future remaining battery capacity SoC _f . When the future battery level SoC _f is less than the reference value S, that is, when it is determined that the future battery level SoC _f is insufficient, the controller 310 adjusts the operating parameters of the radio wave sensor 200 so as to reduce power consumption. Adjust (step S14 to step S17). On the other hand, if the future remaining battery capacity SoC _f is greater than the reference value S, that is, if it is determined that the future remaining battery capacity SoC _f has a margin of a certain level or more, the reduced power consumption is or increase the power consumption (step S18).

The operating parameters that are adjusted for power consumption control are, for example, transmission parameters in the transmitter 331 . If the transmission parameters are adjusted so as to reduce the power consumption, in many cases, the detection accuracy of the radio wave sensor will decrease. On the other hand, if the transmission parameters are adjusted to increase the power consumption, the detection accuracy is improved in many cases. When the remaining battery capacity SoC _f is low, even if the detection accuracy is somewhat sacrificed, the power consumption can be suppressed, thereby suppressing power failure. Note that the operating parameters adjusted for power consumption control may include communication parameters of the communication device 340 that communicates with an external device. A communication parameter is, for example, transmission frequency or transmission power.

A transmission parameter in transmitter 331 is, for example, transmission power. Reducing the transmission power lowers the SN ratio of the received signal of the reflected wave. As a result, the detection area 201 is narrowed and the detection accuracy is lowered. However, power consumption can be reduced by reducing transmission power.

The transmission parameters in transmitter 331 may be parameters related to chirp signals transmitted from transmitter 331 for object detection. A parameter for the chirp signal is, for example, the chirp time (FM chirp time) or the chirp number (FM chirp number). Hereinafter, adjustment of the chirp time will be described with reference to FIG. 6, and adjustment of the number of chirps will be described with reference to FIG.

As shown in FIG. 6, a chirp signal is a signal whose frequency changes over time. The chirp signal is, for example, as shown in FIG. 6, a repetition of a signal whose frequency increases with the lapse of time and returns to the original frequency at once when it reaches a predetermined frequency. This repetition number is called a chirp number (FM chirp number). The time during which the repetition continues is called a chirp time (FM chirp time). Also, the width of frequency change is called a chirp bandwidth. In an embodiment, the chirp signal has a stop period during which no repetition occurs after the chirp time during which the frequency change repeats. A repetition of the frequency change occurs again after the stop period. One period of the chirp signal is the sum of the chirp time and the pause period.

FIGS. 6 and 7 show an example of a normal chirp signal Ch1 (upper side of FIGS. 6 and 7) before power consumption is reduced. The number of chirps in the normal chirp signal Ch1 is _N1 , the chirp time is _T1 , and the chirp bandwidth is _F1 . Note that the length of time for one unit of frequency change repetition is _t1 .

In the radio wave sensor 200, the speed resolution of a detected object such as a vehicle is inversely proportional to the chirp time _T1 . That is, the longer the chirp time _T1 , the finer the speed can be detected. The range resolution to the sensed object is inversely proportional to the chirp bandwidth _F1 . That is, the larger the chirp bandwidth _F1 , the finer the distance can be detected. The maximum detection speed is determined by speed resolution times chirp number. Also, the maximum detectable distance is determined by distance resolution×sampling number. The number of samples is the number of frequency sampling points within one unit of frequency change repetition. When the sampling frequency is constant, the greater the time length _t1 for one unit of frequency change repetition, the greater the number of samplings and the greater the maximum detection distance.

FIG. 6 also shows an example of the chirp signal Ch2 when the chirp time is shortened to reduce power consumption (lower side of FIG. 6). The chirp time _T2 of the chirp signal Ch2 is shorter than the chirp time _T1 of the chirp signal Ch1. In the chirp signal Ch2, the chirp bandwidth F2 is set larger than the chirp bandwidth _F1 of the chirp signal Ch1 in order to shorten the chirp time _T2 while maintaining the number of chirps _N1 =( _N2 ) in the chirp signal _Ch1 . It's getting smaller. As a result, the time length _t2 of the repetition unit of frequency change is shorter than the time length _t1 of the repetition unit in the chirp signal Ch1.

When the chirp time _T2 is shortened like the chirp signal Ch2, the stop period is lengthened and the power consumption is reduced, but the speed resolution is degraded. In addition, since the chirp bandwidth _F2 is reduced, the range resolution is degraded and the maximum detectable range is reduced. Furthermore, the SN ratio also deteriorates. However, the maximum detection speed increases as the speed resolution deteriorates and becomes larger.

FIG. 7 also shows an example of the chirp signal Ch3 (lower side of FIG. 7) in which the number of chirps _N3 is reduced in order to reduce power consumption. In chirp signal Ch3, chirp bandwidth _F3 and time length _t3 of the repetition unit of frequency change are the same as chirp signal Ch1, and only chirp number _N3 is smaller than chirp signal Ch1. As a result, chirp time _T3 of chirp signal Ch3 is shorter than that of chirp signal Ch1.

If the number of chirps _N3 is reduced as in the chirp signal Ch3, power consumption is reduced because the stop time is lengthened, but the speed resolution is degraded due to the shortened chirp time _T3 . Furthermore, the SN ratio also deteriorates. However, since chirp bandwidth _F3 and repetition unit time length _t3 are the same as chirp signal Ch1, range resolution and maximum detectable range are maintained.

A parameter related to the chirp signal may be the length of the pause period in addition to the chirp time and number of chirps. A longer stop period reduces power consumption. However, since the object cannot be detected during the stop period, the detection performance deteriorates. Further, when the radio wave sensor 200 outputs an estimated detection result estimated from the past detection result during the stop period, the longer the stop period, the lower the accuracy of the estimated detection result.

Returning to FIG. 4, when it is determined in step S13 that the remaining battery capacity SoC _f will be insufficient in the future, the controller 310 makes adjustments so that power consumption is reduced. Steps S114 to S17 show an example of power consumption adjustment. In this example, controller 310 adjusts power consumption based on traffic information around radio wave sensor 200 . Traffic conditions affect how the radio wave sensor 200 should operate. For example, if there is no traveling vehicle in and around the detection area 201, there is little need for the radio wave sensor 200 to operate. Further, if the vehicle speed is below a certain level due to congestion or speed regulation, the speed resolution and the maximum detected speed may be low. Conversely, if the vehicle speed is above a certain level, such as above the speed limit, the speed resolution should be degraded to increase the maximum detected speed.

The traffic information used for power consumption adjustment may be the vehicle detection result (detection data) of the radio wave sensor 200 itself, or the vehicle detection result of a sensor other than the radio wave sensor 200 . The other sensor may be another radio wave sensor 810 as shown in FIG. 5, or a roadside sensor 820 of another type other than the radio wave sensor. The controller 310 may acquire traffic information from other radio wave sensors 810 and roadside sensors 820 via the communicator 340, or from a server that provides traffic information, such as the ITS server 830. . Moreover, power consumption may be adjusted by integrating traffic information obtained from a plurality of locations.

The traffic information preferably includes information related to at least one of the number of vehicles traveling in the detection area 201 of the radio wave sensor 200 and the vehicle traveling speed. More specifically, traffic information can include, for example, the presence or absence of traveling vehicles, or the speed of traveling vehicles. The traffic information may include traffic regulation information, for example, speed regulation information, or traffic jam information.

The controller 310 determines the number of traveling vehicles in the detection area 201 and the surrounding area based on the acquired traffic information (step S14). If the number of vehicles is smaller than the threshold _TA , that is, if there are no traveling vehicles or there are very few traveling vehicles, the controller 310 stops radio wave transmission for object detection or sets transmission parameters that reduce power consumption. (Step S15). The transmission parameters to be set may be any of the parameters described above.

When the number of vehicles is greater than the threshold _TA , that is, when there is a certain number of running vehicles, there is a great need for vehicle detection. Therefore, power consumption can be appropriately adjusted by changing the detection performance according to the vehicle speed obtained from the traffic information (steps S16 and 17). For example, when there are many vehicles traveling at high speeds, it is necessary to ensure that the detection area 201 is large to some extent. On the other hand, even if the number of traveling vehicles is large, if the traveling speed is lower than a predetermined threshold value due to congestion, etc., the detection area 201 may be small, so the transmission power can be significantly reduced. . Also, when the traveling speed is low, there is no problem even if the speed resolution is degraded, so parameters related to the chirp signal such as chirp time or number of chirps may be adjusted. Thus, even if the power consumption is reduced, the power consumption can be appropriately adjusted according to the traffic conditions by considering the vehicle traveling speed.

Also, if the traveling speed exceeds a certain level such as exceeding the speed limit, the chirp time may be shortened so as to lower the speed resolution (see FIG. 6). Since the maximum detected speed increases as the speed resolution decreases, it is possible to cope with high running speeds while suppressing power consumption.

Thus, it is effective to shorten the chirp time when the running speed is very low and, conversely, when it is very high. Also, when the traveling speed is a speed that is normally assumed, it is effective to adjust another transmission parameter such as transmission power so as not to impair the speed resolution.

In this embodiment, there are a plurality of adjustable operating parameters (for example, radio wave transmission parameters) for power consumption adjustment. Therefore, even if the power consumption is reduced, by appropriately selecting parameters to be adjusted according to the traffic conditions obtained from the traffic information, it is possible to suppress the adverse effects of reducing the power consumption.

The performance of radio wave sensor 200 changes when operating parameters are adjusted to adjust power consumption. Performance that varies with operating parameter adjustments includes, for example, object detection performance. Detection performance includes, for example, transmission power, speed resolution, distance resolution, maximum detection speed, maximum detection distance, size of detection area, and the like. The performance may include communication performance (transmission frequency, communication distance) with an external device. How the performance of the radio wave sensor 200 changes depends on which parameter is adjusted and how much.

Changes in the performance of the radio wave sensor 200 are desired to be grasped by an external device (for example, another roadside device or vehicle) that operates in cooperation with the radio wave sensor 200 . Therefore, the controller 310 executes a process of transmitting notification data indicating changes in the performance of the radio wave sensor 200 to the outside of the radio wave sensor via the communication device 340 (step S19).

The notification data preferably includes data indicating how performance such as detection performance of the radio wave sensor 200 has changed. Data indicating how the performance has changed, for example, indicates that the transmission of radio waves for object detection has been stopped, indicates how much the transmission power has decreased, or indicates how the velocity resolution has changed. , distance resolution, maximum detection speed, and maximum detection distance. The notification data may also indicate that the remaining battery power in the future is very low and the radio wave sensor 200 may stop working. Note that the notification data transmission timing is not limited to the performance change timing, and may be periodic or necessary timing.

FIG. 8 shows another example of power consumption adjustment processing 350 . In the example shown in FIG. 8, the radio wave sensor 200 performs a plurality of different sensing operations (for example, traffic jam sensing operation and reverse running sensing operation), and transmission parameters for each sensing operation are different. In the example shown in FIG. 8, the processing (steps S11 and S12) up to the calculation of the future remaining battery capacity SoC _f is the same as in the example shown in FIG. In the example shown in FIG. 8, when the future remaining battery capacity SoC _f is determined, the controller 310 makes a determination in step S13 based on the future remaining battery capacity SoC _f to determine whether adjustment of power consumption is necessary. .

When the future remaining battery capacity SoC _f is less than the reference value S, that is, when it is determined that the future remaining battery capacity SoC _f is insufficient, radio wave transmission for a detection operation with a lower priority among the plurality of detection operations is performed. Either stop or adjust the transmission parameters for the lower priority sensing operation so that the power consumption becomes smaller (step S21). Power consumption can be suppressed by stopping execution of operations with low priority or by adjusting transmission parameters so as to reduce power consumption. On the other hand, if the future remaining battery capacity SoC _f is greater than the reference value S, that is, if it is determined that the future remaining battery capacity SoC _f has a certain margin or more, execution of the low-priority operation is resumed. Or continue (step S22).

Incidentally, when adjusting the transmission parameters in step S21, it is preferable to consider traffic information as in the example shown in FIG.

In the example of FIG. 8, the notification data sent out may indicate a reduction or limitation of sensing operations.

[Appendix]

It should be noted that the embodiments disclosed this time should be considered as examples in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above-described meaning, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

11: Vehicle 110: Road 200: Radio wave sensor 201: Detection area 310: Controller 311: Processor 312: Storage device 320: Charge amount estimation table 330: Computer program 331: Transmitter 332: Receiver 333: DSP
334: CPU
340: communication device 350: power consumption adjustment processing 400: battery 410: battery measuring device 440: battery 500: power generation device 610: illuminance meter 620: thermometer 630: timer 700: weather information server 810: radio wave sensor 820: roadside sensor 830: ITS server

Claims (18)

A radio wave sensor that detects an object by reflection of radio waves transmitted as a chirp signal whose frequency changes over time ,
A controller that adjusts the power consumption of the radio wave sensor based on the future remaining battery level of the battery that is charged by the power generation device and supplies power to the radio wave sensor ,
adjusting the power consumption includes adjusting the chirp signal
radio sensor. the controller is configured to estimate a future charge for the battery;
The radio wave sensor according to claim 1, wherein the future battery remaining amount is calculated based on the future charge amount. The radio wave sensor according to claim 1 or 2, wherein the controller estimates the future remaining battery capacity based on data affecting the future remaining battery capacity. The radio wave sensor according to claim 3, wherein the data affecting the remaining battery capacity in the future includes weather forecast data. The radio wave sensor according to any one of claims 1 to 4, wherein the controller adjusts transmission parameters of the radio waves to adjust the power consumption. The radio wave sensor according to any one of claims 1 to 5, wherein the controller adjusts communication parameters with an external device to adjust the power consumption. The radio wave sensor is for traffic monitoring,
The radio wave sensor according to any one of claims 1 to 6, wherein the controller adjusts the power consumption further based on traffic information around the radio wave sensor. The radio wave sensor according to claim 7, wherein the traffic information includes vehicle detection results obtained by the radio wave sensor. The radio wave sensor according to claim 7 or 8, wherein the traffic information includes vehicle detection results obtained by a sensor other than the radio wave sensor. The radio wave sensor according to any one of claims 7 to 9, wherein the controller selects the radio wave transmission parameter to be adjusted for adjusting the power consumption according to the traffic information. The radio wave sensor according to any one of claims 7 to 10, wherein the controller adjusts the power consumption according to the speed of a vehicle around the radio wave sensor when adjusting to lower the power consumption. The radio wave sensor of any one of claims 1 to 11 , wherein adjusting the chirp signal includes adjusting a chirp time. 13. The radio wave sensor of any one of claims 1 to 12 , wherein adjusting the chirp signal includes adjusting a number of chirps. The radio wave sensor according to any one of claims 7 to 11 , wherein the controller adjusts the power consumption according to the number of vehicles around the radio wave sensor when adjusting the power consumption to decrease. The radio wave sensor according to any one of claims 1 to 14 , wherein the controller transmits, to the outside of the radio wave sensor, notification data indicating a change in performance of the radio wave sensor accompanying adjustment of the power consumption. The radio wave sensor according to claim 15 , wherein the notification data includes data indicating how the performance of the radio wave sensor has changed. A control method for a radio wave sensor that detects an object by reflection of a radio wave transmitted as a chirp signal whose frequency changes over time, comprising :
adjusting the power consumption of the radio wave sensor based on the future remaining battery level of a battery that is charged by a power generation device and supplies power to the radio wave sensor ;
adjusting the power consumption includes adjusting the chirp signal
Control method of radio wave sensor. A computer program for operating a computer as a controller of a radio wave sensor that detects an object by reflection of radio waves transmitted as a chirp signal whose frequency changes over time ,
The controller adjusts the power consumption of the radio wave sensor based on a future remaining battery level of a battery that is charged by a power generation device and supplies power to the radio wave sensor,
adjusting the power consumption includes adjusting the chirp signal
computer program.

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