KR101008228B1

KR101008228B1 - System and method for finding direction of signal using multiple sensors

Info

Publication number: KR101008228B1
Application number: KR1020100069969A
Authority: KR
Inventors: 윤상범
Original assignee: 엘아이지넥스원 주식회사
Priority date: 2010-07-20
Filing date: 2010-07-20
Publication date: 2011-01-17

Abstract

Disclosed are a system and a method for detecting the same. More particularly, the present invention relates to a method of detecting a signal direction by arranging a plurality of small sensors to receive and measure signal strength of a signal source, each of which is disposed at a plurality of predetermined positions. Receiving a signal from a signal source and a sensor for measuring the signal strength of the received signal and receiving the signal strength measured by the sensor and a central control unit for detecting the direction of the signal source using the signal strength and the positional relationship of the sensor It relates to a security system and a method for using the same.

Description

Detection system and method using multiple sensors {System and Method for Finding Direction of Signal using Multiple Sensors}

The present invention relates to a system for detecting the direction of a signal and a method thereof, and more particularly, to a plurality of small sensors, arranged at a predetermined position, and measuring the intensity of a signal received by the sensor from a signal source. A direction detection and position estimation technique of a signal source.

In general, the use of radio waves is rapidly increasing with the popularity of wireless communication systems, and various services are required from wireless communication users. Moreover, there is a wave of liberalization in the telecommunications market, and there is a tendency to demand easing of various regulations due to internationalization. Therefore, in the future, there is a need to actively cope with this, and there is also a need for the fair and efficient use of limited frequency resources and the systematic establishment of radio wave order.

In order to effectively manage radio waves, it is necessary to track the weak areas of communication (areas of poor radio quality), track the direction and location of illegal radio transmitters, identify radio users who transmit radio waves above the authorized band, and insulate electrical equipment or power lines. The tracking of the cause of interference signals or noises that are harmful to the radio wave quality caused by this, and the tracking of the source (signal source) of foreign radio waves (foreign radio waves) penetrating into Korea should be considered. However, in order to consider these items, it is necessary to detect the transmission direction of the radio wave of the frequency band of interest.

In general, the direction detection system in wireless communication is a system that can detect illegal radio waves or enemy transmission positions. The direction detection system uses multiple reception channels, and determines the direction of the signal according to the strength and phase of the incident signal. do.

The existing direction detection system (detection system) is to install two or three high-sensitivity detection devices in the city to detect the direction and location of unspecified illegal signals. I have used This means that each probe detects the direction and combines the results to detect the location. Each probe has a performance of about 2 to 5 degrees Root Mean Square (RMS). The method was carried out using the method.

However, the conventional technology has the advantage of securing a wide coverage and high performance detection accuracy, but has been pointed out that it is difficult to secure reliability due to the influence of reflected waves, showing the limitation of accuracy in a large area of buildings and urban areas .

In addition, new paradigms for urban anti-virus devices have been demanded due to the cost of installation and the constraints of large equipment (about 3 billion, 2 sets of fixed equipment, 1 set of mobile equipment).

In view of the above-described problem, the present invention provides a method for detecting a location of a signal source and estimating the position of a signal source from a strength of a signal received by placing small multiple sensors in a city, and a method for detecting the same using the same. We assume 1 technical problem.

In addition, the present invention is connected to the central control unit and the network to check the status of a particular frequency in a specific region to provide a surveillance system that can monitor the illegal signal and the presence or absence of the use of the signal and a method for detecting the same using the second technology It features.

In another aspect, the present invention provides a third technical problem to compensate for errors and errors caused by multipath and non-LOS, and to obtain a result for accurate position estimation.

However, the technical problem of the present invention is not limited to the above-mentioned matters, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above technical problem, the detection system according to the present invention is disposed at a plurality of predetermined positions, respectively, for receiving a signal from a signal source and measuring the signal strength of the received signal and a signal measured by the sensor And a central control unit which receives the intensity and detects the direction of the signal source by using the positional relationship between the signal intensity and the sensor.

Here, the sensor includes an antenna unit for receiving a signal of the signal source, a frequency modulator for down-modulating the frequency of the signal received by the antenna unit to generate a modulated signal, and a signal for measuring the signal strength of the modulated signal. It is preferable to include an intensity measuring unit and an interface unit for transmitting the signal strength measured by the signal strength measuring unit to the central control unit.

In addition, the central control unit preferably controls the antenna unit setting of the sensor so that the sensor receives a signal of a predetermined specific frequency.

In addition, the plurality of positions where the sensor is disposed may be determined in consideration of a line of sight (LOS) between the signal source and the sensor.

More preferably, the sensor and the central control unit may be connected to the wired / wireless network.

In addition, the network may be a direct network or an Ad-hoc network of the sensor and the central control unit.

On the other hand, in order to achieve the above technical problem, the detection method according to the present invention comprises the steps of (a) disposing a sensor at a plurality of predetermined positions, respectively, and receiving a signal of a signal source; Measuring the signal strength; (c) transmitting the measured signal strength to a central control unit; and (d) the direction of the signal source using the positional relationship between the signal strength and the sensor in the central control unit. Detecting the step.

Here, in the step (a), the sensor, the antenna unit for receiving the signal of the signal source, the frequency modulator for down-modulating the frequency of the signal received by the antenna unit to generate a modulated signal, and the modulated signal It may also include a signal strength measuring unit for measuring the signal strength of the signal strength measuring unit and the interface unit for transmitting the signal strength measured by the signal strength measuring unit.

In the step (d), (d1) selecting at least three or more sensors in order of the sensors transmitting the larger signal strength among the signal strengths transmitted to the central control unit, and (d2) the positions of the at least three or more sensors. It is preferable to detect the direction and position of the signal source by triangulation using.

In addition, the step (d), (d11) selecting at least three or more signal strength in the unit cell formed of the sensor disposed in a plurality of predetermined positions in the step (a), (d22) the unit cell Selecting at least three signal strengths in a unit cell adjacent to (d33) selecting a sensor that transmits a signal strength above a predetermined threshold among the signal strengths selected in (d11) and (d22); (d44) It is also preferable to detect the direction and position of the signal source by triangulation using the position of the sensor selected in step (d33).

In addition, the central control unit may control the antenna unit setting of the sensor so that the sensor receives a signal of a predetermined specific frequency.

In addition, in the step (a), the plurality of positions in which the sensor is disposed may be determined in consideration of a line of sight (LOS) between the signal source and the sensor.

Preferably, in step (a), the plurality of positions where the sensor is disposed may be determined in consideration of the free space loss of the signal generated from the signal source.

Preferably, the sensor and the central control unit may be connected to the wired / wireless network.

Also preferably, the network may be a direct network or an Ad-hoc network of the sensor and the central control unit.

According to the detection system according to the present invention grasped from the description of the present specification, it is possible to improve the point of frequent false detection during the detection of the signal source due to the multi-path by the obstacles such as the building layout of the city.

In addition, since the detection system according to the present invention can simultaneously check the distribution of the frequency used simultaneously throughout the city, the operator can conveniently check whether the illegal signal is monitored and whether the signal is used.

In addition, the anti-virus system according to the present invention has the effect of integrating the equipment, which was conventionally divided into a fixed and mobile type into a single system, it is possible to track the position of the signal source in a simple way, and thus the efficient operation and There is a cost saving effect.

1 is a view showing for explaining a conventional method for using a weather probe,
2 is a block diagram schematically showing a sensor of a probe system according to an embodiment of the present invention;
3 is a view illustrating a process of detecting a direction of a signal source in a surveillance system according to an embodiment of the present invention;
4 is a view for explaining a method for communicating with the central control unit in the visitation system according to an embodiment of the present invention,
5 is a view for explaining a method for communicating with a central control unit in a security system according to another embodiment of the present invention;
6 is a graph illustrating an example of free space loss of an RF frequency;
FIG. 7 is a view illustrating a sensor arrangement of a probe system according to an embodiment of the present invention; FIG.
8 is a view illustrating a sensor arrangement of a probe system according to another embodiment of the present invention;
9 is a flowchart illustrating a method for spotting according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description herein, when a component is described as being connected to another component, this means that the component may be directly connected to another component or an intervening third component may be interposed therebetween. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible, even if shown on different drawings. At this time, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, by which the technical spirit of the present invention and its core configuration and operation is not limited.

Prior to describing the anti-virus system according to the present invention, a problem existing in the conventional anti-virus device will be described with reference to FIG. 1.

Basically, the prior art shows good performance in plain areas where there are few cities and mountains. However, in cities with high buildings or in mountainous areas, the performance is very poor due to multipath and non-LOS.

Indeed, many high-rise buildings exist in urban environments such as Seoul, Korea, and multipaths caused by these buildings occur very much. In addition, when the LOS between the signal source and the detection period cannot be measured, the position of the signal source due to the reflected wave is measured, so that an azimuth angle far from the position of the actual transmission (signal) source can be estimated.

Due to these problems, the department that monitors or manages radio waves has a great difficulty in managing illegal signals. This will be described in detail.

1 is a view showing for explaining a conventional method for using a probe.

As shown in FIG. 1, the signal of the path 3 (d3) generated from the signal source S in the case of the existing prober 1 is not directly incident to the prober 1, and in the case of the path 2 (d2) Since the signal reflecting 2 (12) is incident on the probe 1 through the path 1 (d1), the direction detection estimation angle is estimated in the direction of the building 2 (12), which may cause a serious direction detection error.

In addition, the anti-glare accuracy of the conventional anti-glare is represented by the root mean square (RMS) on the basis of the anti-vibrator has a disadvantage that the actual error distance becomes larger as the distance from the transmission source (signal source). This phenomenon is a disadvantage of all conventional probes, and if the distance from the transmission source is about 10KM apart, when the accuracy is defined as 2 degrees RMS, it has a minimum error of 1KM.

Hereinafter, a detailed description will be given of the anti-virus system according to the present invention, which improves the conventional anti-vibration apparatus described above. Hereinafter, the term sensor will be used for the configuration of receiving a signal of a signal source, but the sensor measures the strength of the received signal in addition to receiving the signal of the signal source, and transmits the data to the central control unit or another sensor. It turns out that there is a more appropriate aspect of the use of terms such as so-called cell probes.

2 is a block diagram schematically illustrating a sensor of a probe system according to an embodiment of the present invention.

As shown in FIG. 2, the sensor 100 includes an antenna unit 110, a frequency modulator 120, a signal strength measuring unit 130, and an interface unit 140.

The antenna unit 110 may be formed of a monopole or dipole antenna as a means for receiving a signal generated from a signal source.

The frequency modulator 120 is a means for generating a modulated signal by modulating the frequency of the signal received by the antenna unit 110. The frequency modulator 120 modulates the frequency of the RF signal given to the antenna unit 110 to generate an IF signal. It generates and transfers it to the signal strength measuring unit to be described later.

The signal strength measuring unit 130 is a means for measuring the signal strength of the modulated signal transmitted from the frequency modulator 120 and measures the signal strength using an IF signal.

The interface unit 140 transmits the signal strength measured by the signal strength measuring unit 130 to the central control unit which will be described later. The central control unit and the interface unit may be in communication with each other, and it will be noted that the detailed description thereof may be referred to the following description of FIGS. 4 and 5.

Hereinafter, a description will be given of the anti-virus system for detecting the direction of the signal source using the sensor 100.

3 is a diagram illustrating a process of detecting a direction of a signal source in the anti-virus system according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the anti-virus system includes a plurality of sensors P1 to P5 and a central control unit not shown. Although FIG. 3 illustrates a process of detecting signal sources using five sensors P1 to P5, this is for convenience of description only and the number and arrangement of sensors are not limited to the example of FIG. 3.

3, P1 to P5 are sensors, S is a signal source, 10 is an obstacle, and d1 to d5 are distances between the signal source and the sensor. Looking at the strength of the signal received by the five sensors (P1 ~ P5) when the signal is generated in the signal source (S), because there is an obstacle (10) between the signal source (S) and the sensor P4 sensor (P1 ~ P5) The lowest received signal strength is sensor P4. As such, the difference in signal strength (level) received by the five sensors P1 to P5 is notified to the central control unit, which is not shown, and the central control unit uses the difference in signal levels received by each sensor P1 to P5. By tracking the location of the signal source (S) on the map.

4 is a view for explaining a method for communicating with the central control unit in the anti-virus system according to an embodiment of the present invention, Figure 5 is a communication with the central control unit in the anti-virus system according to another embodiment of the present invention Figure is for explaining the method.

As shown in FIG. 4, the anti-virus system includes a plurality of sensors P1 to P4 and a central control unit 200.

The sensors P1 to P4 are disposed at a plurality of predetermined positions to receive signals generated from the signal sources, respectively, and measure the signal strength of the signals received by the sensors P1 to P4.

The central control unit 200 receives the signal strength measured by the sensors P1 to P4 and detects the direction of the signal source using the signal strength and the positional relationship of the sensor. The central control unit 200 collects data on the signal strength transmitted by the sensors P1 to P4 and uses the signal levels measured by the sensors P1 to P4 to indicate that the current signal is being used in a certain area of the city. It monitors in real time how much signal level it is using and shows it on the map.

That is, the detection system according to the present invention collects signal strengths of specific frequencies simultaneously measured by a plurality of sensors, and measures the position of a signal source simply by measuring in real time what signal is being used in a specific region.

Here, the communication between the central control unit 200 and each sensor (P1 ~ P4) may be by any wired / wireless network, in particular, in the embodiment shown in Figure 4 each sensor (P1 ~ P4) And a direct network connection between the central control unit 200 is used.

Alternatively, as in the other exemplary embodiment shown in FIG. 5, the sensors P1 to P4 and the central control unit 200 are not directly connected to each other by a network but are connected to each other using an Ad-hoc network. Is connected to the central control unit 200 as a final sensor. Ad-hoc networks used herein are generally known techniques and detailed description thereof will be omitted.

In addition, the central control unit 200 receives the signal strength from each sensor, and at the same time, to send a control command to the sensors for the sensors to receive a signal of a predetermined frequency according to the operator's choice It is also possible. This may be implemented by changing the setting of the antenna unit of the above-described sensor according to the control command transmitted through the central control unit 200.

As such, in installing a plurality of sensors at a predetermined position, an appropriate arrangement should be selected to improve the accuracy of the direction detection of the signal source in consideration of the size of the city and the complexity of the city. That is, the distance between the sensors should be set appropriately, which will be described below with reference to FIG. 6.

6 is a graph illustrating an example of free space loss of an RF frequency.

In the example of FIG. 6, free space loss is shown when the frequency is 2.4 GHz. As shown in the graph, when the distance between the sensors is about 1 km, a loss of about 100 dB occurs. Therefore, if it is assumed that the signal of the signal source is generated at about 10 W, it is preferable to set the distance between each sensor so that the minimum sensitivity is -90 dBm or less. In addition, when the distance between the sensors is predetermined, the optimum sensor may be designed by reflecting the sensitivity of the sensor using the free space loss graph of FIG. 6.

Hereinafter, a method of estimating the position of the signal source using the free space loss will be described.

In the free space loss graph shown in FIG. 6, it can be seen that there is a change of 0 to about 93 dB up to a distance of 0 to 500 m, but only a change of about 7 dB occurs to a distance of 500 to 1000 m. Therefore, the most accurate range is between 100 ~ 300m in distance, but the signal level accuracy of-sensor is +/- 2dB, so the accuracy is very good in the range between 0 ~ 300m considering the +/- 2dB error. -Over 500m distance, the accuracy is relatively reduced. Therefore, the distance between the sensors is approximately 1Km, which is twice the distance of 500m, so the distance between each sensor is preferably selected to 1Km. However, depending on the sensitivity of the sensor and the complexity of the city, this optimum distance can of course vary in sensor placement.

The first plan

Considering the relationship between the distance between each sensor and the free space loss, the position can be estimated in the following way.

As the signal strength (level) becomes farther away, the difference in signal level according to the distance becomes smaller. Therefore, when using two or more sensors in such a situation, a larger error occurs. Therefore, only a sensor whose signal level is higher or higher is used. It should be estimated by

Select the sensor position of one sensor with the highest signal strength to estimate the initial position of the estimated signal source, and select the position of the sensor that received the second and third strongest signals from the first sensor. Estimate the direction of the signal source. Thereafter, the position of the signal source is finally determined using the signal level difference between each used sensor.

In this case, when ambiguity occurs, a sensor for receiving the fourth and fifth strongest signals may be selected and used to estimate the position of the signal source.

Second way

If the sensor is arranged at regular intervals and the sensor has good sensitivity, the approximate direction of the signal source is estimated using the signal strength of three or more sensors, and adjacent unit cells (subunits formed by an array of cells) are used. The approximate direction of the signal source is estimated using the signal strengths of three or more sensors. In this way, the cascade method is used to estimate the direction of the signal source using several sensors.

Next, only the results when the signal level is greater than a predetermined threshold value among the estimated azimuths of the direction of the signal source are collected and displayed on the histogram so that the most reliable observation result is signaled by the triangulation algorithm on the electronic map. Estimate the direction and position of the circle. That is, in the second method, the accuracy of the position estimation is improved by using the averaging effect of the reception strengths received by the plurality of sensors of the adjacent cells.

Third way

The third scheme is a method using a combination of the first scheme and the second scheme as described above, that is, the first scheme using a sensor of one unit cell and the second scheme using an averaging effect of the sensors of several unit cells. Will be mixed. A detailed description of the third method may be easily inferred as a description of the first and second methods, and thus description thereof will be omitted.

Thus, a plurality of sensors are disposed in the urban area in consideration of the distance between the sensors and the reception sensitivity, and FIGS. 7 and 8 are referred to as examples.

FIG. 7 is a view illustrating a sensor arrangement of the anti-virus system according to an exemplary embodiment of the present invention, and relates to a case in which the sensor arrangement is disposed in a city center with a so-called honeycomb structure, and FIG. 8 is another embodiment of the present invention. The figure shows in order to explain the sensor arrangement | positioning of the inspection system which concerns on an example, It is related with the case where a sensor arrangement is arrange | positioned in the city center with what is called a rectangular structure.

In general, such a sensor can be used in various forms such as triangular, rectangular, honeycomb, and hexagonal structures. In particular, the sensor may be concentrated in a specific area in consideration of the needs of the operator or the complexity of urban areas and the presence of obstacles. It is possible.

Hereinafter, a description will be given of the anti-virus method according to the present invention.

9 is a flowchart illustrating a method for spotting according to the present invention.

As illustrated in FIG. 9, the method of detecting the signal may include receiving a signal from a signal source using a plurality of sensors (S10), measuring signal strength of the received signal (S20), and measuring the measured signal strength. And transmitting the data from the sensor to the central control unit (S30) and detecting the direction of the signal source using the data on the signal strength at the central control unit (S40).

FIG. 9 briefly illustrates a method for detecting the air, but in the method for detecting the air, a control command for setting each sensor may be transmitted from the central control unit so that each sensor receives a signal of a specific frequency. It can be inferred from this, and the details of other methods of detection can also be referred to in the description of the detection system, so the detailed description is omitted here.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof fall within the spirit of the present invention.

S: signal source 100: sensor
110: antenna 120: frequency modulator
130: signal strength measurement unit 140: interface unit
P1, P2, P3, P4, P5: Sensor 1,2,3,4,5 200: Central control unit

Claims

Sensors disposed at a plurality of predetermined locations, respectively, for receiving signals from signal sources and measuring signal strength of the received signals; And
A detection system comprising a central control unit for receiving the signal strength measured by the sensor to detect the direction and position of the signal source by using the signal strength and the positional relationship of the sensor, the sensor detects the signal of the signal source An antenna unit for receiving, a frequency modulator for down-modulating the frequency of the signal received by the antenna unit to generate a modulated signal, a signal strength measuring unit for measuring the signal strength of the modulated signal, and a signal strength measuring unit Investigation system characterized in that it comprises an interface unit for transmitting the signal strength to the central control unit.

delete

The method of claim 1,
And the central control unit controls the setting of the antenna unit such that the sensor receives a signal of a predetermined specific frequency.

The method of claim 1,
And a plurality of positions at which the sensor is disposed are determined in consideration of a line of sight (LOS) between the signal source and the sensor.

The method of claim 1,
And the sensor and the central control unit are connected to a wired / wireless network.

The method of claim 5,
And the network is a direct network or an ad hoc network of the sensor and the central control unit.

(a) receiving a signal of a signal source by disposing a sensor at a plurality of predetermined positions, respectively;
(b) measuring a signal strength of the received signal;
(c) transmitting the measured signal strength to a central control unit; And
(d) detecting the direction and position of the signal source by using the signal strength and the positional relationship of the sensor in the central control unit, wherein the sensor of the step (a) comprises: An antenna unit for receiving the original signal, a frequency modulator for down-modulating the frequency of the signal received by the antenna unit to generate a modulated signal, a signal strength measuring unit for measuring the signal strength of the modulated signal and the signal strength measurement And the interface unit for transmitting the signal strength measured by the unit to the central control unit.

delete

The method of claim 7, wherein step (d),
(d1) selecting at least three or more sensors among the signal strengths transmitted to the central control unit in order of the sensors transmitting the larger signal intensities; And
(d2) detecting the direction and position of the signal source by triangulation using the positions of the at least three sensors.

The method of claim 7, wherein step (d),
(d11) selecting at least three signal strengths in a unit cell formed of a sensor disposed at a plurality of predetermined positions in step (a);
(d22) selecting at least three signal strengths in a unit cell adjacent to the unit cell;
(d33) selecting a sensor that transmits a signal strength equal to or greater than a predetermined threshold value among the signal strengths selected in steps (d11) and (d22); And
and (d44) detecting the direction and the position of the signal source by triangulation using the position of the sensor selected in the step (d33).

The method of claim 7, wherein
And the central control unit controls the setting of the antenna unit such that the sensor receives a signal of a predetermined specific frequency.

The method of claim 7, wherein
The method of claim 2, wherein the plurality of positions where the sensor is disposed are determined in consideration of a line of sight (LOS) between the signal source and the sensor.

The method of claim 7, wherein
The method of claim 2, wherein the plurality of positions in which the sensor is disposed are determined in consideration of the free space loss of the signal generated from the signal source.

The method of claim 7, wherein
And the sensor and the central control unit are connected to a wired / wireless network.

The method of claim 14,
And the network is a direct network or an ad hoc network of the sensor and the central control unit.