KR101229028B1 - Sensor node having radar and method for detecting vehicle using sensor node - Google Patents

Abstract

Disclosed are a sensor node having a radar and a vehicle detection method using the sensor node. The sensor node according to an embodiment of the present invention extracts traffic information of a vehicle including a vehicle presence, a vehicle speed, occupancy time, occupancy rate, a vehicle length, and a vehicle type by using a radar and a geomagnetic sensor. Accordingly, accurate and reliable traffic information can be provided.

Description

Sensor node having radar and method for detecting vehicle using sensor node

One aspect of the present invention relates to a vehicle detector, and more particularly, to a radar vehicle detector capable of detecting a driving vehicle or a parked vehicle.

There are various vehicle detectors for detecting a traveling vehicle or a stopped vehicle. For example, the vehicle detector may be a loop detector, an image detector, an ultrasonic detector, a radar detector, or a geomagnetic detector.

The loop detector is the most widely used vehicle detector and measures the occupancy of the vehicle by detecting the change in inductance when there is a metallic object on the road by applying an oscillation signal to the loop coil embedded by cutting the road surface. Loop detectors are more vulnerable to cutting during road construction than ultrasonic and imaging methods, but they are cheaper than other detectors and are widely used as vehicle occupancy sensors because they have stable performance regardless of the surrounding environment.

However, the loop detector is greatly affected by the inductance change depending on the pavement of the road and the materials used. Therefore, there is a remarkable difference in performance depending on whether there is a failure in construction and the shape and size of the detector, and there are many cases of disconnection due to road works such as road construction and sewer construction after construction. Because of this, if the re-installation in the same location or the re-installation is impossible, there is a problem that the entire system must be moved.

Image detectors and ultrasonic detectors are affected by the climate and the surrounding environment, and thus there is a problem in continuously extracting accurate traffic information. Radar detectors are mainly used to obtain speed information of multi-lane vehicles, but they are expensive to install and require professional personnel for maintenance.

Geomagnetic detectors can be miniaturized compared to loop systems and have the advantages of battery-based wireless systems, thereby solving the maintenance and installation problems of loops. However, since the vehicle detector does not have a uniform detection area, the detection area for each vehicle type is formed differently so that the exact detection position is not known, and it is difficult to accurately determine the parking state of the vehicle. Furthermore, since the magnitude of distortion of the magnetic field varies depending on the characteristics of the vehicle, it is difficult to detect the change in the magnetic field within a certain range for all the vehicles.

According to an aspect, the present invention proposes a vehicle detector capable of accurately detecting a vehicle's presence, vehicle speed, occupancy time, occupancy rate, and vehicle length, and classifying a vehicle model, without being affected by climate change or road environment.

According to an aspect of the present invention, a sensor node detects a vehicle by using a radar for detecting a radar signal reflected from a transmission, a geomagnetic sensor for detecting a magnetic field signal according to a change in magnitude of the geomagnetic intensity, and a radar signal detected from the radar The controller detects the traffic information of the vehicle by interlocking the vehicle detection result through the radar and the pattern recognition result through the geomagnetic sensor, and the wireless communication unit transmitting the detected traffic information to the outside. It includes.

According to another aspect, a vehicle detecting method using a sensor node includes detecting a vehicle using a radar signal detected through a radar, pattern recognition of a magnetic field signal detected through a geomagnetic sensor, and detecting a vehicle through a radar Detecting the traffic information of the vehicle by interlocking the result with the pattern recognition result through the geomagnetic sensor, and transmitting the detected traffic information to the outside.

According to an embodiment, it is possible to accurately determine whether the vehicle is detected in a predetermined region by using the radar signal of the radar. Furthermore, traffic information including the speed, occupancy time, occupancy rate, and length of the vehicle may be accurately extracted through the radar. Using radar, you can get a clear view of traffic information on your vehicle without being affected by climate change or the environment.

Furthermore, it is possible to grasp the vehicle model through the unique pattern analysis of the vehicle using the geomagnetic sensor. In this case, since the accuracy of classifying the vehicle and the vehicle may be increased by using a single vehicle detector, accurate and reliable traffic information may be provided.

Furthermore, when the magnetic field signal is formed into a hill pattern during the intrinsic pattern analysis of the vehicle using the geomagnetic sensor, the classification process of the vehicle and the vehicle is simplified, thereby reducing the cost and power. In addition, by using a pattern transformation that lowers the magnetic field signal to low resolution through bit operation or bit shift in analyzing the intrinsic pattern of the vehicle, it is possible to reduce the computational load for patterning.

Furthermore, as AC coupling is performed on the signal output from the geomagnetic sensor, a separate operation and circuit for baseline setting are unnecessary, thereby simplifying the circuit configuration.

Furthermore, since the vehicle detector of the present invention is a battery-based device, it is possible to manufacture a small size and can be used for a long time after construction, so the maintenance cost is low. In addition, as road damage is minimized, it can be used as a vehicle detector with high reliability.

Furthermore, the power supply can be controlled according to the magnitude of the signal detected from the radar or the geomagnetic sensor or each component, in particular, the transmission module and the reception module of the radar, thereby accurately detecting the vehicle and reducing power consumption.

Furthermore, the traffic information system can be used to guide the parking lot management system or the lane-sensitive left turn signal and the ITS vehicle detector because the vehicle can accurately determine the parking condition of the vehicle.

1 is a block diagram of a wireless sensor network system according to an embodiment of the present invention;
2 is a block diagram of a sensor node according to an embodiment of the present invention;
3 is a detailed configuration diagram of a control unit of a sensor node according to an embodiment of the present invention;
4A and 4B are reference views for explaining power management of a sensor node according to an embodiment of the present invention;
5 is a reference diagram for explaining a process of determining the presence or absence of a vehicle using a radar of a sensor node according to an embodiment of the present invention;
6 is a reference diagram for explaining a process of calculating a speed, occupancy rate, and length of a vehicle using a radar of a sensor node according to an embodiment of the present invention;
7 is a reference diagram for explaining a process of detecting a vehicle model using a radar and a geomagnetic sensor of a sensor node according to an embodiment of the present invention;
8 is a circuit diagram showing a simplified geomagnetic sensor correction circuit according to an embodiment of the present invention;
9A to 9C are reference diagrams for explaining hill patternization of a magnetic field signal output from a geomagnetic sensor according to an embodiment of the present invention;
10 is a flowchart illustrating a vehicle detecting method using a sensor node according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention; In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the terms described below are defined in consideration of the functions of the present invention, and this may vary depending on the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

The present invention relates to a radar vehicle detector which can extract traffic information such as the presence or absence of the vehicle, the occupancy and the speed of the vehicle in each detection area by detecting the vehicle through the radar. The present invention can use a wireless sensor network to remotely transmit the extracted traffic information. Hereinafter, the wireless sensor network system will be described with reference to FIG. 1. However, the present invention is not limited to the wireless sensor network-based environment, but may be applied to all communication environments for transmitting and receiving data based on vehicle detection.

1 is a block diagram of a wireless sensor network system according to an embodiment of the present invention.

Referring to FIG. 1, the wireless sensor network system includes a sensor node 10, a base station 30, and a management server 40, and may further include a sink node 20.

The sensor node 10 detects the driving vehicle or the parking vehicle by using the radar signal detected through the radar and the magnetic field signal detected by the geomagnetic sensor. There may be a plurality of sensor nodes 10.

According to one aspect, the sensor node 10 uses the radar signal of the radar for detecting the vehicle. The radar transmits a very short pulse wave through an antenna and receives a signal reflected back to a metal object such as a vehicle through the antenna to determine whether a metal object such as a vehicle exists. Using the radar signal, it is possible to determine the presence or absence of the vehicle in a predetermined space without being affected by climate change or the surrounding environment. The radar may be a UWB radar (ultra wideband radar). UWB radars are ultra-wideband, capable of transmitting large amounts of data over wide spectral frequencies at low power over short distances.

According to another aspect, the sensor node 10 uses the magnitude change of the geomagnetic intensity for vehicle detection. That is, the change in the earth's magnetic field according to the movement of the vehicle in the predetermined space is used to output the voltage. By using the magnitude change of the geomagnetic intensity, it is possible to detect the vehicle more accurately than when using the roof coil or the ultrasonic sensor, and the installation is simple and the installation cost can be reduced. In addition, it can be installed anywhere indoors or outdoors, so there is no restriction on the installation area.

According to the present invention, the sensor node 10 detects a vehicle using a radar signal detected from a radar, and pattern-recognizes a magnetic field signal detected from a geomagnetic sensor. Then, the traffic information of the vehicle is detected by interlocking the vehicle detection result through the radar and the pattern recognition result through the geomagnetic sensor. Traffic information includes vehicle presence, speed, occupancy time, occupancy, vehicle length and vehicle type. The detailed configuration of the sensor node 10 will be described later in FIGS. 2 and 3, the detailed operations in FIGS. 4 to 7, and the vehicle detection process in FIG. 10.

The base station 30 collects traffic information detected through the sensor node 10 and delivers the traffic information to the management server 40. In this case, the sink node 20 may collect traffic information detected through the sensor node 10 and relay the traffic information to the base station 30. The management server 50 may manage or monitor a vehicle in a predetermined space by using the traffic information received from the base station 40.

According to an embodiment, the vehicle detector of the present invention may be applied to a traffic information system. The traffic information system collects information data on various roads such as intersections and highways in order to perform traffic management in real time, concentrates them in the traffic situation room, and resolves traffic jams or provides traffic information to the general public through the control of traffic lights. to be.

According to another embodiment, the vehicle detector of the present invention can be applied to a parking management system. The parking management system detects a vehicle leaving or entering a parking space and recognizes the detected vehicle, and manages or monitors parking using the same. The sensor node 10 may be embedded or attached to the parking space.

1, when the sensor node 10 detects a vehicle in a parking space, wirelessly transmits the detected vehicle information to the base station 30 through a wireless sensor network, and manages the server 40. ) Receives the vehicle information from the base station 30 to manage or monitor the parking of the detected vehicle. At this time, it may further include a sink node 20 to collect the vehicle information sensed through the sensor node 10 to relay to the base station (30).

On the other hand, the application field of the vehicle detector of the present invention is illustrated as a traffic information system and a parking management system to help the understanding of the present invention, the application field is not limited to this, it is obvious that it can be applied in various other fields.

2 is a block diagram of a sensor node 1 according to an embodiment of the present invention.

Referring to FIG. 2, the sensor node 1 includes a radar 10, a geomagnetic sensor 11, a control unit 12, a wireless communication unit 13, and a power supply unit 14.

The sensor node 1 is a compact vehicle detector that uses the battery 140 as a power source and transmits and receives data wirelessly through the wireless communication unit 13. The power manager 142 manages the battery 140. The controller 12 detects the driving vehicle or the parking vehicle, and uses the radar 10 and the geomagnetic sensor 11 for this purpose. That is, the controller 12 extracts traffic information by analyzing signals detected by the radar 10 and the geomagnetic sensor 11. Traffic information includes vehicle speed, occupancy, length and vehicle type. The wireless communication unit 13 wirelessly transmits the traffic information extracted from the control unit 12 to the outside.

According to one embodiment, the control unit 12 detects the vehicle using the radar signal detected from the radar 10, calculates the presence or absence of the vehicle, the speed of the vehicle, the occupancy of the vehicle and the length of the vehicle.

According to an embodiment, the controller 12 uses the geomagnetic sensor 11 for vehicle detection. The geomagnetic sensor 11 detects a change in the magnitude of the geomagnetic intensity in a predetermined space. In this case, the controller 12 performs pattern recognition on the magnetic field signal detected by the geomagnetic sensor 11. Pattern recognition involves analyzing waveform data of a magnetic field signal and extracting intrinsic features (patterns) of the data. At this time, the pattern to be recognized is created as a standard pattern, and the recognition pattern is most similar to the standard pattern by comparing (pattern matching) the standard pattern and the input pattern at the time of recognition. By simply patterning the waveform of the geomagnetic sensor 11, the vehicle model of the vehicle can be grasped.

According to an exemplary embodiment, the controller 12 performs a hill pattern on the magnetic field signal. Hill-Pattern (HP) is a conversion process that greatly simplifies a magnetic field signal into a {+1, 0, -1} signal. In other words, instead of a signal waveform with tiny tips, it is simplified to a smooth pattern with peak and valley. At this time, essential pattern information necessary for classifying a vehicle and a vehicle is maintained. Hill-Pattern simplifies the classification process, resulting in cost and power savings. Application examples of the hill pattern will be described later with reference to FIGS. 9A to 9C.

According to another exemplary embodiment, the controller 12 may pattern the geomagnetism change amount by lowering the resolution to low resolution. For example, when the signal output from the geomagnetic sensor 11 is converted into a digital signal through the ADC, the resolution can be reduced by bit-calculating the 12-bit ADC to 8 bits. The magnitude level of the signal is then lowered from (0 to 4095) to (0 to 255). Alternatively, you can lower the resolution by bit shifting to 4 bits. The magnitude level of the signal is then lowered to (0-15). This is a case where it is assumed that the magnitude of the signal varies from 0 to 2 ⁿ -1 steps (assuming n bits). Accordingly, the computational load for patterning can be reduced.

According to the above-described configuration, the sensor node 1 of the present invention is not affected by climate change and surrounding environment change, and in particular, it is possible to grasp the presence or absence of vehicle detection in a predetermined area by using UWB radar, and thus extracts traffic information with high accuracy. can do. Furthermore, by using the geomagnetic sensor to classify the vehicle as well as the vehicle through the unique pattern analysis of the vehicle, the accuracy is improved. Furthermore, since the sensor node 1 is a battery 140 based device, the sensor node 1 can be made compact and can be used for a long time after construction. In addition, as road damage is minimized, it can be used as a highly reliable vehicle detector.

3 is a detailed block diagram of the control unit 12 of the sensor node 1 according to an embodiment of the present invention.

Referring to FIG. 3, the controller 12 includes a speed calculator 120, an occupancy calculator 122, a length calculator 124, a pattern recognizer 126, and a vehicle model detector 128.

When the sensor node having the first radar and the sensor node having the second radar are installed at a predetermined distance from each other, the speed calculator 120 may target the first radar signal of the first radar and the second radar signal of the second radar. The vehicle speed is calculated using the delay time between the first radar signal and the second radar signal. The occupancy calculator 122 measures occupancy time of the first radar signal and the second radar signal, and calculates occupancy of the vehicle using the measured occupancy time. The length calculator 124 calculates the length of the vehicle using the vehicle speed calculated by the speed calculator 120 and the occupancy time measured by the occupancy calculator 122. An embodiment of a vehicle speed, occupancy and length calculation process using a radar is described below in FIG. 6.

On the other hand, the pattern recognition unit 126 analyzes the magnetic field signal detected by the geomagnetic sensor 11 to extract a unique pattern through pattern recognition. The vehicle type detection unit 128 detects the vehicle type of the vehicle by matching the unique pattern extracted through the pattern recognition unit 126 with the detected length information of the vehicle using the radar signal detected by the radar 10. An embodiment of a vehicle type detection process of a vehicle using a geomagnetic sensor and a radar will be described later with reference to FIG. 7.

4A and 4B are reference diagrams for explaining power management of a sensor node according to an embodiment of the present invention.

2 and 4A, the power management unit 142 of the power supply unit 14 manages the battery 140 to control the magnitude of the magnetic field signal detected by the geomagnetic sensor 11 or the radar signal detected by the radar 10. If is less than the preset reference, cut off the power supply. As shown in FIG. 4A, the power manager 142 wakes up each sensor at predetermined intervals to detect a vehicle and cuts off power supply when the vehicle is not detected. ))do. Accordingly, power consumption may be reduced by reducing battery 140.

2 and 4B, the power manager 142 powers on the transmission module of the radar 10 to transmit a short TX pulse through the transmission antenna. Then, after a predetermined time elapses after powering on the transmitting module, the receiving module of the radar 10 is powered on. Subsequently, after a predetermined time elapses after the receiving module is powered on, the receiving module is powered off.

The RF signal transmitted through the transmitting antenna hits a reflective object (such as an iron plate) and returns. The reason for powering on the receiving module after a certain time is that the TX pulse is reflected directly by obstacles such as foreign objects and returned to the vehicle. This is to prevent errors that fail to detect.

For example, when the sensor node 1 is installed on the floor, obstacles that can reflect cans, plastic bags (metal coated) or other RF signals may be in close contact with the sensor node 1. Therefore, in the present invention, in order to detect and detect the Tx pulse reflected from the minimum vehicle height and returned from the minimum vehicle height in order to detect the presence of the vehicle through the radar 10, the receiving module is powered on after a predetermined time elapses. At this time, the predetermined time is variable.

Furthermore, the detection module even detects signals reflected from objects that are too far away (e.g., ceilings of indoor parking lots, other structures), which makes the vehicle less accurate. Therefore, the power management unit 142 powers on the receiving module of the radar 10 only for a time reflected and returned from the vehicle of a predetermined distance or more. For example, if only a radar signal from the sensor node 1 to a radius of 1 m is detected, the receiving module only needs to be powered on until the time required to transmit and reflect the signal to the corresponding 1 m. As a result, the vehicle can be detected accurately and power can be saved.

5 is a reference diagram for explaining a process of determining whether a vehicle is present using a radar of a sensor node according to an embodiment of the present invention.

Referring to FIG. 5, a carrier is transmitted at regular intervals using a radar, and when a vehicle passes on a detector, the carrier is reflected by the vehicle and returned to the vehicle, and the presence or absence of the vehicle is converted into 'H' and 'L' signals. Output The 'H' signal means vehicle detection, and the 'L' signal means vehicle detection. Using the radar, it is possible to accurately determine whether the vehicle is in a parked state.

6 is a reference diagram for explaining a process of calculating a speed, occupancy rate, and length of a vehicle using a radar of a sensor node according to an embodiment of the present invention.

Referring to FIG. 6A, a speed, occupancy rate, and length of a vehicle may be calculated using a multi-vehicle detector. In this case, it is assumed that the first sensor node # 1 having the first radar and the second sensor node # 2 having the second radar are installed at a predetermined distance d.

Referring to FIG. 6B, a vehicle passing through each of the sensor nodes # 1 and # 2 has a delay time T_Diff according to the speed of the vehicle between the radar detection signals. The speed of the vehicle is calculated using the 'T_Diff_ON' (vehicle entry time difference) and 'T_Diff_OFF' (vehicle advance time difference). The vehicle occupancy ratio is extracted using occupancy times 'OC1' and 'OC2' of each radar signal of each sensor node # 1 and # 2. Furthermore, the length of the vehicle can be calculated using the calculated vehicle speed and occupancy time.

FIG. 7 is a reference diagram for explaining a process of detecting a vehicle model using a radar and a geomagnetic sensor of a sensor node according to an embodiment of the present invention.

Referring to FIG. 7, the waveform of the magnetic field signal detected by the geomagnetic sensor is patterned together with the traffic information extracted using the radar. Although the detection area of each geomagnetic sensor is uncertain for each vehicle type, as shown in FIG. 7, the geomagnetic sensor can measure a specific waveform according to the vehicle. Thus, the magnetic field signal is simply patterned and matched with the vehicle length information measured by the radar. Classify.

8 is a circuit diagram illustrating a simplified geomagnetic sensor correction circuit according to an embodiment of the present invention.

Referring to FIG. 8, the present invention may determine whether a vehicle exists by using a radar, and thus may simply design a configuration and an operation of a geomagnetic sensor used for pattern extraction according to vehicle movement.

The value output by detecting the magnitude change of the geomagnetic intensity of the geomagnetic sensor is weak to the influence of the surrounding magnetic field, and the output signal of the geomagnetic sensor may change according to the measurement environment such as temperature, location, time, and season. In addition, it varies greatly depending on the assembling state of the geomagnetic sensor and the degree of inclination, and may be saturated by the strong magnetic field. Accordingly, since the magnitude and the offset of the signal are changed by the characteristics of the sensor itself and the magnetic field other than the geomagnetic generated in the surroundings, it is difficult to determine a consistent standard every measurement, and thus accurate measurement may not be possible. Accordingly, a procedure for setting a baseline and correcting an output value of the geomagnetic sensor according to the baseline is required. Here, the baseline is a calibration factor that is a reference value for correcting the magnitude of geomagnetic intensity. In general, a potentiometer is used to set the baseline. The potentiometer outputs a variable reference signal or fixed bias.

However, since the geomagnetic sensor according to the present invention is primarily used for pattern extraction according to vehicle movement, the above-described operation and circuit for setting the baseline can be eliminated. To this end, the present invention simply AC-couples the output voltage of the geomagnetic sensor at a hardware level, and applies a predetermined power supply (eg, a 1/2 power supply) to the amplifier OPAMP as a bias. Then, since the output value of the geomagnetic sensor is maintained at a predetermined value (eg, an intermediate value) of the ADC input range, the magnetic field change of the geomagnetic sensor is then detected, and only the amount of change is checked.

Specifically, as shown in Figure 8, the geomagnetic sensor correction circuit of the present invention is based on the AC coupling result of the AC coupling unit 80 and the AC coupling unit 80 for AC coupling to the signal output from the geomagnetic sensor The amplification unit 82 amplifies the AC component signal outputted accordingly, and the output signal amplified by the bias applying unit 86 and the amplifying unit 82 applying a predetermined voltage to the amplifying unit 82 as a bias. And an ADC unit 84 for converting and outputting the signal.

The AC coupling unit 80 may be implemented by connecting in series with a capacitor, but is not limited thereto. The AC coupling unit 80 filters the DC component signal among the signals output from the geomagnetic sensor and passes only the AC component signal. Then, the amplifier 82 may amplify only the AC component signal, that is, the amount of change in the magnetic field, and the amplified signal is used for pattern extraction and analysis later.

In general, in the case of DC coupling, a circuit for scanning the baseline for setting the Vref of the amplifier is added. However, in order to simplify this, the present invention AC-couples the output signal of the geomagnetic sensor through the AC coupling unit 80, and transmits only the change value of the magnetic field to the amplifier 82, and the amplifier 82 amplifies it. Accordingly, the bias applying unit 86 only needs to apply a fixed bias (for example, 1/2 vcc) to the fixed Vref value in the amplifier 82. As a result, a separate operation and circuit for setting the baseline are unnecessary, thereby simplifying the circuit configuration.

9A to 9C are reference diagrams for explaining Hill patternization of a magnetic field signal output from a geomagnetic sensor according to an exemplary embodiment of the present invention.

9A to 9C, the present invention may simplify a magnetic field signal different for each vehicle and a vehicle into a hill pattern. 9A and 9B illustrate examples of simplifying the magnetic field signal in the Hill pattern, and FIG. 9C illustrates examples of the magnetic field signals for each vehicle type to be simplified in the Hill pattern. According to an embodiment, the present invention simplifies the magnetic field signal of each vehicle type shown in FIG. 9C into a Hill pattern and stores it as a standard pattern, and then outputs it through a geomagnetic sensor and compares the pattern with the signal simplified by the Hill pattern to match the vehicle type. Determine.

10 is a flowchart illustrating a vehicle detecting method using a sensor node according to an embodiment of the present invention.

2 and 10, the sensor node 1 detects a radar signal transmitted and reflected back through the radar 10, and then changes according to the magnitude of the geomagnetic intensity through the geomagnetic sensor 11. A magnetic field signal is detected (1010).

Subsequently, the vehicle is detected using the radar signal detected through the radar 10 (1020). According to one aspect, the vehicle speed is calculated using the delay time between the plurality of radar signals. The occupancy time of each radar signal is measured, and the occupancy rate of the vehicle is calculated using the measured occupancy time. In addition, the vehicle length and occupancy time may be used to calculate the length of the vehicle.

Subsequently, the sensor node 1 pattern recognizes the magnetic field signal detected by the geomagnetic sensor 11 (1030). At this time, the magnetic field signal detected by the geomagnetic sensor 11 is analyzed to extract a unique pattern through pattern recognition.

According to an embodiment, in the step 1030 of pattern recognition of the magnetic field signal detected by the geomagnetic sensor 11, while maintaining the magnetic field signal pattern information necessary for classifying a vehicle and a vehicle, {+1, 0, -1 } Patterning can be done using a Hill pattern transform that simplifies the signal.

According to another embodiment, in step 1030 of pattern recognition of the magnetic field signal sensed by the geomagnetic sensor 11, the magnetic field signal may be patterned by using a pattern transformation that lowers the magnetic field signal to low resolution through bit operations or bit shifts.

Meanwhile, before step 1030 of pattern recognition of the magnetic field signal detected by the geomagnetic sensor, AC coupling is performed on the signal output from the geomagnetic sensor 11, and the AC component signal is output according to the AC coupling result. The method may further include amplifying the amplifier, applying a predetermined voltage to the amplifier as a bias, and converting the output signal amplified by the amplifier into a digital signal.

Subsequently, the traffic information of the vehicle is detected by interlocking the vehicle detection result through the radar 10 and the pattern recognition result through the geomagnetic sensor 11 (1040). According to an aspect, the extracted unique pattern is matched with the detected length of the vehicle by using the radar signal to detect a vehicle model of the vehicle. The detected traffic information is transmitted to the outside through the wireless communication unit 13 (1050).

The embodiments of the present invention have been described above. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

1: Sensor node 10: Radar
11: geomagnetic sensor 12: control unit
13 wireless communication unit 14 power unit
120: speed calculator 122: share calculator
124: length calculation unit 126: pattern recognition unit
128: vehicle model detection unit

Claims (16)

A radar for detecting a radar signal reflected and returned during transmission;
A geomagnetic sensor that detects a magnetic field signal according to the magnitude change of the geomagnetic intensity;
A geomagnetic sensor correction unit configured to correct an output signal of the geomagnetic sensor through AC coupling;
The length information of the vehicle is calculated using the laser signal detected from the radar, the pattern of the magnetic field signal corrected by the geomagnetic sensor correction unit is heel-patterned, and the pattern is recognized, and the length information of the vehicle calculated by the plurality of radars. A control unit which detects traffic information of the vehicle by interlocking a pattern recognition result through the geomagnetic sensor; And
A wireless communication unit for transmitting the detected traffic information to an outside;
Sensor node comprising a. The method of claim 1,
The traffic information of the vehicle includes at least one of a vehicle presence, vehicle speed, occupancy time, occupancy rate, vehicle length, and vehicle type. The apparatus of claim 1, wherein the control unit
A pattern recognition unit for extracting a unique pattern through pattern recognition by analyzing a magnetic field signal sensed by the geomagnetic sensor; And
A vehicle type detection unit detecting a vehicle type of the vehicle by matching the unique pattern extracted through the pattern recognition unit with length information of the vehicle detected using the radar signal;
Sensor node comprising a. The apparatus of claim 1, wherein the control unit
A speed calculator configured to calculate a vehicle speed using delay times between the plurality of radar signals;
An occupancy calculator for measuring occupancy time of each radar signal and calculating occupancy of the vehicle using the measured occupancy time; And
A length calculator configured to calculate the length of the vehicle using the vehicle speed calculated by the speed calculator and the occupancy time measured by the occupancy calculator;
Sensor node comprising a. The apparatus of claim 1, wherein the control unit
And the magnetic field signal is patterned by using Hill pattern transformation to simplify the {+1, 0, -1} signal while maintaining the pattern information necessary for classifying the vehicle and vehicle. The apparatus of claim 1, wherein the control unit
And patterning the magnetic field signal by using a pattern transformation that lowers the magnetic field signal to low resolution through bit operation or bit shift. The method of claim 1, wherein the geomagnetic sensor correction unit,
An AC coupling unit for AC-coupling the signal output from the geomagnetic sensor;
An amplifier for amplifying the AC component signal output according to the AC coupling result;
A bias applying unit applying a predetermined voltage as a bias to the amplifier; And
An ADC unit converting the output signal amplified by the amplifier into a digital signal and outputting the digital signal;
Sensor node comprising a. The method of claim 1, wherein the sensor node,
battery; And
A power management unit managing the battery and blocking power supply to save power when a magnitude of the detected magnetic field signal or radar signal is less than a preset reference;
Sensor node characterized in that it further comprises. The method of claim 8, wherein the power management unit,
Control the power supply of the transmitting module and the receiving module of the radar, supplying power to the transmitting module and supplying power to the receiving module after a first time has elapsed, and after the second time has elapsed, Sensor node, characterized in that to cut off the power supply. The method of claim 9,
The first time is a time for blocking a radar signal reflected back from an obstacle adjacent to the sensor node after the signal is transmitted through the transmission module, and the second time is a radar signal reflected back from a certain distance or more. Sensor node, characterized in that the time for blocking. delete delete delete delete delete delete

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