KR101128509B1 - Method and system for threshold estimation of intrusion detection in UWB sensor - Google Patents

Abstract

In order to estimate the threshold value for intrusion detection in the sensor, the received signal value is calculated from the received signal received from the outside, and then the average reception level value is calculated from the calculated received signal value. The threshold value is calculated using the average reception level value. At this time, the average reception level value is a value in consideration of the performance deviation in the UWB sensor having a hardware deviation.

Description

침입 Method and system for threshold estimation of intrusion detection in UWB sensor

The present invention relates to a method and apparatus for estimating an intrusion detection threshold in consideration of hardware deviation in a UWB sensor.

In general, in a wireless system, an automatic gain control (AGC) is used to operate a wireless system within a predetermined range of a change in a received signal, or hardware is designed to have a certain performance.

However, when the automatic gain control device is used for the wireless sensor, there is a problem that the price of the wireless sensor is expensive. In addition, when a system such as an actual ultra wideband (UWB) is designed to have a certain hardware performance, there is a problem in that hardware complexity increases.

On the other hand, in the case of a wireless sensor that does not use the automatic gain control device, the price is lowered and the hardware complexity is lowered, while the deviation of hardware performance is large, causing serious performance degradation.

Accordingly, the present invention provides an apparatus and method for estimating a threshold for intrusion detection in consideration of a performance deviation due to hardware deviation in a UWB sensor having various hardware deviations.

Apparatus for estimating the threshold for intrusion detection in the sensor which is one feature of the present invention for achieving the technical problem of the present invention,

An analog-digital converter for converting an analog received signal received through the sensor into a digital received signal and outputting a received signal value; an average received level calculator for calculating an average received level value using the received signal value; And a threshold calculator which calculates a threshold value using the average reception level value and a plurality of coefficients stored in advance.

Method for estimating the threshold value for intrusion detection in the sensor which is another feature of the present invention for achieving the technical problem of the present invention,

Calculating a received signal value from a received signal received from the outside; Calculating an average reception level value from the calculated reception signal value; And calculating a threshold value using the calculated average reception level value.

According to an embodiment of the present invention, by setting a threshold for intrusion detection of an intruder in consideration of hardware deviation for the sensor for intrusion detection, not only does the sensor have a constant detection area but also can be implemented with low complexity, so that the manufacturing cost Can be lowered.

1 is an exemplary view illustrating a sensing area and a monitoring area of a general UWB sensor.
2 is a structural diagram of a general UWB sensor.
3 is a structural diagram of a threshold estimating apparatus of a UWB sensor according to an embodiment of the present invention.
4 is a flowchart illustrating a method of estimating an intrusion threshold according to an embodiment of the present invention.
5 is an exemplary diagram illustrating a relationship between an intruder detection threshold value and an average reception level according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

Hereinafter, a method and apparatus for estimating an intrusion detection threshold in consideration of hardware deviation in a UWB sensor will be described with reference to the accompanying drawings. Before describing an embodiment of the present invention, a general UWB sensor and an intrusion detection area using the same will be described.

1 is an exemplary view illustrating a sensing area and a monitoring area using a general UWB sensor.

As shown in FIG. 1, when an intruder is detected using a UWB sensor, an area in which the UWB sensor is installed is divided into a surveillance area and a detection area around the UWB sensor.

The surveillance area refers to a region where intruders can be detected by the physical characteristics of the antenna of the UWB sensor when the intrusion occurs, and the detection region refers to an area set to monitor the intrusion as much as desired within the surveillance area. A UWB sensor for monitoring an intrusion within such an area will be described with reference to FIG. 2.

2 is a structural diagram of a general UWB sensor.

As shown in FIG. 2, the UWB sensor is divided into a transmitter 10 and a receiver 20. The transmitter 10 includes a first signal generator 11, a first mixer 12, a second signal generator 13, a power amplifier 14, and a delayer 15, and a receiver 20. Includes a low noise amplifier 21, a second mixer 22, a third signal generator 23, a third mixer 24, an integrator 25, and a threshold estimator. The threshold estimator includes an analog digital conversion (ADC) 26 and an alarm generator 27.

The first signal generator 11 of the transmitter 10 generates a signal to check whether motion is detected within a preset area. The generated signal is called a UWB signal. The second signal generator 13 generates a carrier signal.

The first mixer 12 mixes the UWB signal generated by the first signal generator 11 and the carrier signal generated by the second signal generator 13, and the power amplifier 14 performs the first mixer 12. ) Amplifies the power of the mixed signal and outputs it through the transmit antenna. The delay unit 15 delays and outputs the UWB signal generated by the first signal generator 11 for a predetermined time.

The low noise amplifier 21 of the receiver 20 amplifies and outputs a signal received through the receive antenna from the outside after being output from the transmit antenna. The third signal generator 23 generates a carrier signal, and the second mixer 22 mixes the carrier signal generated by the third signal generator 23 and the received signal amplified by the low noise amplifier 21. .

The third mixer 24 mixes the signal mixed in the second mixer 22 and the UWB signal delayed through the delay unit 15 of the transmitter 10. The integrator 25 integrates the signals output from the third mixer 24 for an integration time and outputs an analog signal. The ADC 26 converts the analog signal output from the integrator 25 into a digital received signal, and the alarm generator 27 generates an alarm. In this case, a component including the ADC 26 and the alarm generator 27 is referred to as a threshold estimator, and the method of estimating the threshold value in the threshold estimator is shown in Equation 1 below.

Here y _k means the received signal value after the digital conversion. w _k means a noise signal. At this time, the noise follows a normal distribution, with an average of 0 and a variance of σ ² .

μ denotes an average reception level value (referred to as an average reflection reception level) at which a transmission signal is reflected and received, and is calculated as μ = V _bias + G. In this case, V _bias is the supply voltage of the ADC 26 and G is the gain of the signal received reflected.

To detect an intruder, use T = aμ (a> 0), which is an arbitrary value of the average reflection reception level. For example, if y _k ≥ T, it is assumed that an intrusion has occurred, and accordingly, the alarm generator 27 generates an alarm signal.

In the case of using a general UWB sensor, when a large volume of UWB sensors are produced, the Vbias value is different due to the deviation between the sensors, and the G value is different due to the performance deviation between the sensors. In addition, in the case of a system using a UWB sensor, since the system has a very weak signal strength and a wide frequency bandwidth, variations between the sensors (V _bias and G) occur more.

In other words, in case of detecting intrusion detection with the same threshold value (T = aμ) in a system having a large deviation between V _bias and G between sensors, a large deviation occurs in the sensing area of the sensor, which causes many problems in actual field application. . Table 1 shows the detection area when using a general UWB sensor. Table 1 shows the detection area when one threshold is used for intrusion detection.

0 degrees 90 degrees 180 degrees 270 degrees First sensor 1.3 m 1.7m 2.2m 1.5m Second sensor 0.8 m 1.2m 1.7m 1.0m Third sensor 1.0m 2.0m 2.4m 1.8m Fourth sensor 1.5m 2.0m 2.8m 2.2m Fifth sensor 1.4m 1.5m 1.6m 1.6m

Therefore, in the embodiment of the present invention, a threshold value for detecting an intruder's intrusion is considered in consideration of hardware deviation. The threshold estimating apparatus will be described with reference to FIG. 3.

3 is a structural diagram of a threshold estimating apparatus of a UWB sensor according to an embodiment of the present invention.

As shown in FIG. 3, the threshold estimating apparatus 100 includes an ADC 110, an average reception level calculator 120, a threshold calculator 130, and an alarm generator 140.

The ADC 110 converts a plurality of analog signals received from a transmission antenna (not shown) into a plurality of digital received signals and outputs the converted signals.

The average reception level calculator 120 receives a plurality of digital reception signals converted and output from the ADC 110 and calculates an average reception level value. A method of calculating an average reception level value from the digital reception signal will be described later.

The threshold calculator 130 calculates and outputs a threshold value by using the average reception level value calculated by the average reception level calculator 120 and two coefficients β ₀ and β ₁ stored in advance. The threshold calculator consists of a square 131, two multipliers 132 and 133, and an adder 134. A method of calculating a threshold value from an average reception level value and a method of calculating two pre-stored coefficients will be described later.

The alarm generator 140 generates an alarm based on the threshold value calculated by the threshold calculator 130.

A method of estimating the threshold value in consideration of hardware deviation will be described with reference to FIG. 4 through the apparatus for estimating the intruder threshold value.

4 is a flowchart illustrating a method of estimating an intruder threshold according to an embodiment of the present invention.

)을 출력한다(S100). 이때 수신 신호 값(

)은 다음 수학식 2와 같이 정의할 수 있다. As shown in FIG. 4, the ADC 110 of the threshold estimating apparatus converts a plurality of analog received signals into digital received signals to obtain a received signal value (

) Is output (S100). The received signal value (

) Can be defined as in Equation 2 below.

는 l번째 샘플의 디지털 변환을 수행하고 난 후의 수신 신호 값이다. 여기서 샘플이라 함은 복수의 센서 중 임의로 선택된 센서를 의미한다.Where k is the time index, N is the number of samples, and l ∈ {1, 2,... , N}.

Is the received signal value after performing digital conversion of the l th sample. Herein, the sample refers to a sensor arbitrarily selected from among a plurality of sensors.

는 l번째 샘플의 잡음 신호를 나타내며, 이때 잡음은 정규 분포를 따르며 평균은 0, 분산은 σ²이다.

Denotes the noise signal of the l-th sample, where noise follows a normal distribution, with an average of 0 and a variance of σ ² .

와 같이 계산된다. 여기서

는 l번째 샘플의 ADC(110)로 공급되는 전압이고,

는 l번째 샘플로 반사되어 수신되는 신호의 이득을 의미한다.μ _(l) is the average received level value received from the reflected sensor of the first sample,

Is calculated as here

Is the voltage supplied to the ADC 110 of the l th sample,

Denotes the gain of the received signal reflected by the l-th sample.

를 계산하는 방법에 대하여 상세하게 설명하면, 먼저 ADC(110)에서 수신 신호 값(

)이 출력되면, 평균 수신 레벨 계산부(120)는 수신한 디지털 수신 신호의 값으로부터 평균 수신 레벨 값(μ_(l))을 계산한다(S110).

In detail, a method of calculating the received signal value in the ADC 110 (

) Is output, the average reception level calculator 120 calculates an average reception level value μ _(l) from the value of the received digital reception signal (S110).

A method of calculating an average reception level value μ _(l) , which is an average reception level value received by the UWB sensor of the first sample, uses Equation 3 below.

When the average reception level calculator 120 calculates the average reception level value μ _(l) , the threshold calculator 130 receives the average reception level value μ _(l) to calculate a threshold value ( S120). At this time, the threshold value is shown in Equation 4 below.

That is, the average reception level value μ _(l) input to the threshold calculator 130 is input to the square 131 and the first multiplier 132, respectively. The multiplier 131 multiplies the average reception level value μ _(l) by a square, and the first multiplier 132 multiplies the prestored first coefficient β ₀ and the average reception level value μ _(l) by a square. Multiply and print.

The second multiplier 133 multiplies and outputs the average reception level value μ _(l) multiplied by the power of the power 131 by the second coefficient β ₁ stored in advance. The adder 134 adds outputs of the first multiplier 132 and the second multiplier 133 and outputs the threshold value.

At this time, a method of calculating the first coefficient β ₀ and the second coefficient β ₁ stored in advance is as follows.

를 이용한다. 모든 샘플에 일정한 T 대신에 각 샘플에 적합한 임계값

를 이용하면 각 샘플에 적합한 임계값을 갖게 되어, 복수의 센서들은 일정한 감지 영역을 가질 수 있게 된다. 그러나, 센서 제조 공정상에서 10⁶ 이상의 샘플들이 제작된다고 가정하면, 모든 샘플의

및

를 측정하여 침입 감지를 위한 임계값

를 얻는 것은 불가능하다.When detecting an intruder's intrusion using Equation 2 described above, an arbitrary value of the average reflection reception level of the sample, which is each arbitrary UWB sensor

Use Threshold appropriate for each sample instead of constant T for all samples

Using a threshold value suitable for each sample, the plurality of sensors can have a constant detection area. However, assuming that at least 10 ⁶ samples are produced in the sensor manufacturing process,

And

The threshold for intrusion detection by measuring

It is impossible to get it.

를 계산하기보다, 실제 측정된 데이터를 기반으로

를 추정하는 방법을 이용하기로 한다. 즉, 일정한 감지 영역을 가지기 위해, 평균 수신 레벨 값에 대한 임계값을 측정한다. Thus, in the embodiment of the present invention, the threshold for all samples

Rather than calculating, based on the actual measured data

We will use the method of estimating. That is, in order to have a constant sensing area, the threshold value for the average reception level value is measured.

We then calculate an approximate threshold for each sample. When the approximate threshold calculated by Equation 4 is applied, it is possible to have a constant sensing area in every sample without obtaining the threshold for every sample.

Equation 4 is used to calculate an approximate threshold. At this time, the mean square error between the actual threshold and the approximate threshold is expressed by Equation 5.

Through Equation 5, the optimal solution β _{0, opt} and β _{1, opt} values can be obtained using Equation 6 below.

The optimal solution β _{0, opt} and β _{1, opt} values by Equation 6 are given by Equation 7 below.

의 계산이 가능하다. 즉, 제1 계수 및 제2 계수는 임계값과 평균 수신 레벨을 이용하여 수학식 7과 같이 계산될 수 있다. 이때, 각 샘플의 평균 수신 신호 레벨 μ_(l)은 각 샘플에서의 수신 신호 처리를 통해 쉽게 획득할 수 있으며, 본 발명의 실시예에서는 이에 대한 설명을 생략하기로 한다.Approximate thresholds in each sample according to Equation 4, using the optimal solution β _{0, opt} , β _{1, opt} coefficients (ie, first coefficient and second coefficient) shown in equation (7).

The calculation of is possible. That is, the first coefficient and the second coefficient may be calculated by using Equation 7 using the threshold value and the average reception level. At this time, the average received signal level μ _(l) of each sample can be easily obtained through the received signal processing in each sample, and the description thereof will be omitted in the embodiment of the present invention.

As described above, when the threshold is calculated by the threshold calculator 130, the alarm generator 140 may compare the digital received signal output from the ADC 110 and the threshold output by the threshold calculator 130. Received to determine whether the alarm occurs (S130). That is, when the digital reception signal value output from the ADC 110 is greater than or equal to the threshold value calculated by the threshold calculator 130, the alarm generator 140 considers that an intrusion has occurred and generates an alarm signal (S140).

As such, when determining a threshold for determining whether an intruder exists when hardware deviation occurs according to an embodiment of the present invention, the average reception level value is selected by selecting representative samples without measuring the threshold for all samples. Calculate and estimate the threshold based on this. In addition, the sensing area in the case of using the UWB sensor according to an embodiment of the present invention is shown in Table 2.

0 degrees 90 degrees 180 degrees 270 degrees First sensor 1.5m 1.6m 1.7m 1.6m Second sensor 1.4m 1.5m 1.7m 1.8m Third sensor 1.4m 1.5m 1.8m 1.6m Fourth sensor 1.5m 1.7m 1.6m 1.7m Fifth sensor 1.4m 1.5m 1.6m 1.6m

As shown in Table 2, it can be seen that the shape of the area detected between the sensors, which are samples, is uniform as there is no hardware deviation. That is, when a 360 degree detection area occurs based on the sensor, as shown in Table 2, the first sensor can detect a 0 degree part up to 1.5 m, a 90 degree part 1.6 m, a 180 degree part 1.7 m, and The 270-degree part can detect up to 1.6m. Similarly, another sensor, the second sensor, has a sensing area of 0, 90, 180, and 270 degrees of 1.4 m, 1.5 m, 1.7 m and 1.8 m, respectively.

That is, as shown in Table 1, the first sensor and the second sensor, which are conventionally implemented by applying one threshold value, exhibit a large deviation and have an irregular sensing area. On the other hand, it can be seen that the first sensor and the second sensor, which are implemented through the method of estimating the threshold value using the average reception level value in consideration of hardware deviation, according to the embodiment of the present invention, have a similar sensing area. .

And the intruder threshold value for the deviation correction between samples will appear as shown in FIG.

5 is an exemplary diagram illustrating a relationship between an intruder detection threshold value and an average reception level according to an embodiment of the present invention.

As shown in Figure 5, it can be seen that the threshold value of the intruder for the deviation correction between samples increases as the average reception level value is higher. In other words, in the method of estimating a general threshold value, the detection area becomes very irregular because only one threshold value is applied to samples having a high hardware deviation. However, as in the embodiment of the present invention, the threshold value is applied in consideration of the hardware deviation. This allows the detection area to appear regularly.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (10)

An apparatus for estimating a threshold for intrusion detection in a plurality of sensors, the apparatus comprising:
An analog-digital converter converting a plurality of analog received signals received through the sensor into digital received signals and outputting a plurality of received signal values;
An average reception level calculator for calculating an average reception level value using a plurality of reception signal values output from the analog-digital converter; And
A threshold calculator configured to calculate a threshold value using the average reception level value and a plurality of pre-stored coefficients
Includes, the threshold calculator,
A squarer for outputting an average reception level squared value by multiplying the average reception level value;
A first multiplier for multiplying and outputting an average received level squared value multiplied by the squared multiplied by a first coefficient among the plurality of coefficients;
A second multiplier configured to multiply the average reception level value by a second coefficient of the plurality of coefficients to output the multiplier; And
And an adder configured to add the output values of the first multiplier and the second multiplier, respectively, and output the sum value as the threshold value. The method of claim 1,
An alarm generating unit for generating an alarm by determining whether an alarm occurs for the analog received signal based on the calculated threshold value and the plurality of received signal values.
Threshold estimating apparatus comprising a. delete The method of claim 1,
And the first coefficient and the second coefficient are respectively calculated based on an average reception level and a threshold value. In the method for estimating the threshold for intrusion detection in a plurality of sensors,
Calculating a plurality of received signal values based on a sum of an average received level value of a sample, which is a randomly selected sensor among the plurality of sensors, and a noise signal of the sample, from a plurality of received signals received from the outside;
Calculating an average reception level value from the plurality of received signal values; And
Calculating a threshold value using the calculated average reception level value
Threshold estimation method comprising a.
delete The method of claim 5,
Computing the threshold value,
Calculating an average reception level squared value by multiplying the average reception level value;
Calculating a first value by multiplying the mean reception level squared value by a pre-stored first coefficient;
Calculating a second value by multiplying the average reception level value by a second stored coefficient; And
Calculating the threshold by adding the first value and the second value;
Threshold estimation method comprising a. The method of claim 7, wherein
The first coefficient is

Is calculated through the second coefficient

Where T ^(l) is the threshold and μ _(l) is the average reception level, l represents the l th sample and l ∈ {1, 2, ..., N}, where N is the number of samples)
Threshold estimation method calculated through. The method of claim 5,
After calculating the threshold,
Determining whether an alarm occurs using the plurality of received signal values and the threshold value;
Threshold estimation method further comprising. 10. The method of claim 9,
Determining whether the alarm occurs,
Determining whether the plurality of received signal values are greater than the calculated threshold value; And
Generating an alarm signal informing of an intrusion if the plurality of received signal values are greater than the threshold value;
Threshold estimation method comprising a.

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