KR102065980B1 - Method for detecting target - Google Patents

Abstract

The present invention relates to a target detection method. More specifically, provided is the target detection method for detecting a target using constant false alarm rate (CFAR) processing which variably operates a threshold value in accordance with a surrounding environment. According to an embodiment of the present invention, the target detection method comprises: a process of receiving a radar signal in a detection area; and a process of detecting a target from the radar signal by the CFAR processing. The process of detecting a target may include: a process of dividing the detection area into several portions; a process of individually determining a scale factor for each divided detection area and setting a threshold value of the CFAR processing; and a process of detecting a target from the radar signal having an output value larger than the threshold value.

Description

Target Detection Method {METHOD FOR DETECTING TARGET}

The present invention relates to a target detection method, and more particularly, to a target detection method for detecting a target by using a certain false alarm rate processing that operates a threshold value in accordance with the surrounding environment.

A radar system is a system that detects a target by transmitting a signal to detect a target and receiving and processing a signal reflected from the target. In this case, the received radar signal includes a signal for a target as well as a clutter signal by various features. Due to such clutter signals, the level of radar detection rate is a key factor for signal strength.

In other words, increasing the threshold of the signal strength for the target detection reduces the probability of mistaken for the clutter signal as a target to increase the detection accuracy, but may cause a target missed without being detected. Conversely, lowering the threshold of signal strength increases the probability of detecting a target and can detect many targets, but the clutter signal increases the false positive rate. Accordingly, a constant false alarm rate (CFAR) process is used to variably operate the threshold value according to the surrounding environment.

In general, in the constant false alarm rate processing, the ambient environment signal value is calculated using a reference cell around the test cell, and the threshold value is set by multiplying the calculated ambient environment signal value by a scaling factor. Here, a fixed constant value is used as the scale factor.

However, in the case of using a constant value fixed as the scale factor, there is a problem that it is difficult to satisfy the false alarm rate required by the radar system in the environment in which the clutter signal changes fluidly. In particular, when a fixed constant value is used as a scale factor in detecting a sea area where the wave height continuously changes due to wind intensity, etc., the false alarm rate of the radar system increases rapidly due to the clutter signal that changes dynamically. There was this.

KR 10-2015-0131779 A

The present invention provides a target detection method that can set a threshold value for a certain false alarm rate processing by varying the scale factor in an environment in which the clutter signal is fluidly changed.

Target detection method according to an embodiment of the present invention, the process of receiving a radar signal in the detection area; And detecting a target from the radar signal by a constant false alarm rate (CFAR) process, wherein the detecting of the target comprises: dividing the detection area into a plurality of targets; Individually determining a scale factor for each of the divided detection regions and setting a threshold for the constant false alarm rate (CFAR) processing; And detecting a target from the radar signal having an output value larger than the threshold.

In the process of dividing the detection area into a plurality, the detection area may be divided into a plurality of parts according to the azimuth direction and the distance direction.

The detection area may include a sea area where the crest is constantly changing.

Target detection method according to an embodiment of the present invention, the process of receiving a radar signal in the detection area; And detecting a target from the radar signal by a constant false alarm rate processing (CFAR), wherein the detecting of the target comprises: dividing the detection area into a plurality of targets; Separately determining a scale factor from the clutter signal extracted for each of the divided detection regions, and setting a threshold of the predetermined false alarm rate processing; And detecting a target from the radar signal having an output value larger than the threshold.

Target detection method according to an embodiment of the present invention, the process of receiving a radar signal in the detection area; And detecting a target from the radar signal by a cell average constant false alarm rate (CA-CFAR) process, wherein the detecting of the target comprises: dividing the detection area into a plurality of targets; Determining a scale factor for each of the divided detection regions and setting a threshold value of the CA-CFAR processing; And detecting a target from the radar signal having an output value larger than the threshold.

The setting of the threshold value of the CA-CFAR processing may include: storing an output value of a clutter signal in a plurality of cells for each of the divided detection areas; Scanning the plurality of cells and checking an output value of a test cell and an output value of a reference cell; Calculating a reference level by averaging the output values of the reference cells; Determining a scale factor by comparing the output value of the test cell with the reference level; And setting a threshold value by multiplying the scale factor by an ambient environment signal value.

Target detection method according to an embodiment of the present invention, the process of receiving a radar signal in the detection area; And detecting a target from the radar signal by an order statistical constant false alarm rate (OS-CFAR) process, wherein the detecting of the target comprises: dividing the detection area into a plurality of targets; Determining a scale factor individually for each of the divided detection regions and setting a threshold value of the sequence statistical constant alarm rate (OS-CFAR) process; And detecting a target from the radar signal having an output value larger than the threshold.

The setting of the threshold value of the sequence statistics constant false alarm rate (OS-CFAR) process may include: storing an output value of a clutter signal in a plurality of cells for each of the divided detection regions; Scanning the plurality of cells and checking an output value of a test cell and an output value of a reference cell; Arranging output values of the reference cells in order of magnitude and selecting output values having a predetermined rank to calculate a reference level; Determining a scale factor by comparing the output value of the test cell with the reference level; And setting a threshold value by multiplying the scale factor by an ambient environment signal value.

According to the target detection method according to an embodiment of the present invention, the distribution of the clutter signal is predicted in an environment in which the clutter signal changes in fluid, and the scale factor corresponding to the false alarm rate required by the radar system is predicted according to the predicted result. Adaptive adjustment can improve target detection probability.

In addition, the artificial scale factor does not need to be adjusted according to the environment when the radar system is operated, and the target signal is processed so that the influence of the target signal is not reflected on the reference level, thereby enabling more efficient target detection.

1 is a diagram schematically illustrating a threshold setting method of a constant false alarm rate processing according to an embodiment of the present invention.
2 is a diagram showing a clutter signal spectrum in a resolution region.
3 is a diagram showing a state of determining a scale factor according to an embodiment of the present invention.
4 is a diagram illustrating a method of determining a scale factor according to another embodiment of the present invention.
5 shows a histogram generated from a difference value of an output value of a test cell with respect to a reference level.
6 is a view schematically showing a target detection method according to an embodiment of the present invention.
7 is a diagram illustrating a state in which a detection area is divided into a plurality.
8 is a view showing a state of detecting a target according to an embodiment of the present invention.
9 is a view showing a state of detecting a target according to another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments of the present invention make the disclosure of the present invention complete and the scope of the invention to those skilled in the art. It is provided to inform you completely. Like numbers refer to like elements in the figures.

1 is a diagram schematically illustrating a method for setting a threshold value of a predetermined false alarm rate process according to an embodiment of the present invention.

Referring to FIG. 1, in the method of setting a threshold value of a predetermined false alarm rate processing according to an embodiment of the present invention, a process of storing output values of a received signal in a plurality of cells (S110), scanning the plurality of cells, Determining an output value and an output value of the reference cell (S120), calculating a reference level from the output value of the reference cell (S130), and determining a scale factor by comparing the output value of the test cell with the reference level. And a step S150 of multiplying the scale factor by an ambient environment signal value to set a threshold.

The threshold value for detecting the target in the constant false alarm rate processing is set by storing output values of the radar signal in a plurality of cells and sequentially designating the plurality of cells with respect to the radar signal including the target signal and the clutter signal. The ambient signal value is calculated using the neighboring cell of the test cell. The ambient signal value calculated as described above is multiplied by a scaling factor as shown in Equation 1 below to set a threshold value.

[Equation 1]

Here, when using a fixed constant value as the scale factor, there is a problem that it is difficult to satisfy the false alarm rate required by the radar system in an environment in which the clutter signal changes fluidly. In particular, when a fixed constant value is used as a scale factor in detecting a sea area where the wave height continuously changes due to wind intensity, etc., the false alarm rate of the radar system increases rapidly due to the clutter signal that changes dynamically. There was this.

The magnitude distribution of the clutter signal in the resolution region generally follows the K-distribution. The K-distribution varies with the shape parameter v and the scale parameter, and the clutter signal spectrum in the resolution region according to the shape parameter v is shown in FIG. Here, Fig. 2 (a) shows the clutter signal spectrum when the shape parameter v is 5, and Fig. 2 (b) shows the clutter signal spectrum when the shape parameter v is 0.5. One drawing.

As shown in FIG. 2, it can be seen that as the shape parameter ν decreases, the spectrum of the clutter signal has a high amplitude value and shows a sharp characteristic. That is, when detecting a target in a marine environment where the wave height is constantly changing, the clutter signal spectrum is spiked with a high amplitude value as the shape parameter ν changes, in which case a fixed constant value is obtained. Using as a scale factor causes a problem that the clutter signal is mistaken as a target signal and the false alarm rate is increased.

Accordingly, in the threshold setting method of the constant false alarm rate processing according to an embodiment of the present invention, the distribution of the clutter signal is predicted in an environment in which the clutter signal changes in fluid, and the radar system requests the false alarm rate according to the predicted result. By adaptively adjusting the matching scale factor, it is possible to improve the target detection probability.

Hereinafter, a detailed process of the threshold setting method of the constant false alarm rate processing according to an embodiment of the present invention will be described in detail.

In operation S110, an output value of the received signal is stored in a plurality of cells of a register. Here, unlike the radar signal described later, the received signal may include a clutter signal from which the target signal is excluded. That is, in the threshold setting method of the constant false alarm rate processing according to an embodiment of the present invention, first, the distribution of the clutter signal is predicted in an environment in which the clutter signal changes in a fluid manner. In order to predict the distribution of the clutter signal, it is necessary to include only the clutter signal in which the target signal is excluded in the received signal.

In order to store the output value of the clutter signal from which the target signal is excluded, a signal in the detection area may be received in a state where the target does not exist, and the output value of the received signal may be stored, but includes a target signal and a clutter signal. The method may include receiving a signal and removing a target signal from the received signal. That is, a signal in the detection area may be received in the presence of a target, and the output signal of the clutter signal from which the target signal is excluded may be stored by removing the target signal from the received signal. Here, the target signal refers to a signal having a large radar cross section (RCS), and such a target signal may include a signal reflected from a land or an island in a marine environment as well as a signal reflected from a target. . As such, the process of removing the target signal may receive a signal in the detection area in the state where the target exists, and may remove the signal having the amplitude value or more set from the received signal as the target signal.

In the process of storing the output value of the received signal (S110), the output value of the received signal may be arranged in a range direction and sequentially stored in a plurality of cells. In this case, the plurality of cells may be arranged in one direction, and the output values of the received signals are sequentially stored in the plurality of cells arranged in one direction according to the distance direction.

In operation S120 of checking the output value of the test cell T and the output value of the reference cell, the window unit W designates at least one cell of a plurality of cells as the test cell T, and the test cell ( A cell located within a predetermined distance from T) is designated as a reference cell (R). In this case, the reference cell R may include a cell positioned within a predetermined distance to both sides of the test cell T among the plurality of cells, and in this case, located within the same distance to the left and right sides of the test cell T, respectively. It may include a cell.

That is, the window unit W may select, for example, a cell at a predetermined position as the test cell T, and designate a cell located within a predetermined distance from both sides of the test cell T as the reference cell R. . In addition, the window unit W may designate at least one guard cell G adjacent to both sides of the test cell T, as shown in FIG. 3. Here, the output value of the guard cell G does not affect the process of calculating a reference level to be described later (S130). The window part W is a cell located within a predetermined distance, for example, a distance of 3, from the guard cell G located at the leftmost side of the test cell T among the plurality of cells, and located at the rightmost side from the test cell T. A cell located within a predetermined distance, for example, a distance of 3 from the guard cell G may be designated as the reference cell R. In this case, the number of guard cells G and a predetermined distance from the test cell T to be designated as the reference cell R may be set in advance, and the reference cell will be described later using the determined reference cell R. To calculate the level.

In operation S130, the reference level is calculated from the output value of the received signal stored in the reference cell R.

Major CFAR algorithms used in radar systems include CA Cell Average CFAR (CF CFAR) and Ordered Statistic CFAR (OS CFAR). CA CFAR is widely used in uniform noise environment. CA CFAR uses an average value of the output value of the reference cell R as shown in FIG. 3 as a reference level for comparing with the test cell T. On the other hand, OS CFAR uses the output value of the specific reference cell (R) as shown in Figure 4 as a reference level for comparison with the test cell (T). OS CFAR can be used in non-uniform noise environments or in multiple target situations, sorting the reference cells (R) in ascending order, for example according to the magnitude of the output value, and the nth reference cell of the sorted reference cells (R). Use the output value of (R) as the reference level.

In operation S140, the scale factor is determined by comparing an output value of the test cell T with a reference level. In this case, the determining of the scale factor (S140) may include calculating a difference value of an output value of the test cell T with respect to a reference level, generating a histogram indicating a frequency distribution state of the difference value, and the difference value. The method may include calculating a cumulative frequency while decreasing the difference value from a maximum value of and calculating the scale factor from a difference value when the cumulative frequency coincides with a set number of false alarms.

The process of calculating the difference value of the output value of the test cell T with respect to the reference level compares the output value of the test level T with the reference level and calculates the difference value. Here, the difference value means a signal ratio of the test cell T to the reference level signal. Therefore, the difference value may be calculated by dividing the output value of the test cell T by the reference level. However, in general, since the output value of the reference cell R and the output value of the test cell T have a unit of decibels (dB), in this case, the difference between the output value of the test cell T with respect to the reference level is It may be calculated by subtracting the reference level from the output value of the test cell (T).

Hereinafter, the output value of the reference cell R and the output value of the test cell T have a unit of decibels (dB), and the difference value is calculated by subtracting the reference level from the output value of the test cell T. For example, the output value of the reference cell R and the output value of the test cell T are not converted into decibels (dB), but the output value of the test cell T is divided by the reference level. Of course, the difference value may be calculated by using a scale factor to be described later.

The process of calculating the difference value is performed for each of the specified test cells T by designating a plurality of cells as test cells T, respectively. As a result, when a difference value is calculated for each of a plurality of cells, a process of generating a histogram indicating a frequency distribution state of the difference value is performed as shown in FIG. 5. Here, the histogram shows the number of cells (Y-axis of FIG. 5) having the difference values β sequentially aligned (X-axis of FIG. 5) and each having the aligned difference values β. In FIG. 5, the number of cells having a difference value β of 3.5 to 3.6 dB is four, the number of cells having a difference value β of 3.6 to 3.7 dB is three, and the difference value β of 3.7 to 3.7. The number of cells with 3.8 dB and the number of cells having a difference value β of 3.8 to 3.9 dB are two, respectively, and the number of cells having a difference value β of 3.9 to 4 dB is shown. have.

The cumulative frequency is then calculated while decreasing the difference value β from the maximum value of the difference value β (in the range of 3.8 to 3.9 dB in FIG. 5) to determine the scale factor. That is, the cumulative frequency is 1 in the region where the difference value β is 3.9 to 4 dB, and the cumulative frequency is 3 in the region where the difference value β is 3.8 to 3.9 dB, and the difference value β is The cumulative frequency is 5 in the region of 3.7 to 3.8 dB, and the cumulative frequency is 8 in the region of 3.6 to 3.7 dB.

At this time, the scale factor is calculated from the difference value β when this cumulative frequency coincides with the set number of false alarms. Here, the number of false alarms is a value that is arbitrarily set according to a system for target detection, and when the number of false alarms that can generate false alarms in a certain false alarm rate process is set to 5, for example, the difference value β is 3.7 to An area of 3.8 dB corresponds to the set number of false alarms. In this case, the scale factor may be calculated from a minimum value among regions representing a difference value β having a cumulative frequency that matches the set number of false alarms. That is, in FIG. 5, the difference value β when the cumulative frequency coincides with the set number of false alarms has a value of 3.7 dB, and the scale factor is substituted for this difference value β by the following equation (2). Calculate (K).

[Equation 2]

Here, Equation 2 is derived when the output value of the reference cell R and the output value of the test cell T have a unit of decibel (dB), and as described above, the output value of the reference cell R When the output value of the test cell T and the output value of the test cell T are not converted in decibels (dB), the difference value when the cumulative frequency and the set number of false alarms coincide may be calculated as a scale factor.

In this way, the scale factor is calculated from the difference value β when the cumulative frequency from the maximum value of the difference value β coincides with the set number of false alarms in the histogram indicating the frequency distribution state of the difference value β. It is possible to predict the distribution of clutter signals in an environment in which the signal changes in a fluid manner, and to adaptively adjust the scale factor corresponding to the false alarm rate required by the radar system according to the predicted result.

On the other hand, the threshold setting method of the predetermined false alarm rate processing according to an embodiment of the present invention can be applied to a recording medium storing a computer program for performing the above method.

That is, the threshold setting method of the constant false alarm rate processing according to an embodiment of the present invention may be implemented in the form of computer readable programming language code recorded on a computer readable recording medium. The computer-readable recording medium can be any data storage device that can be read by a computer and can store data. For example, the computer-readable recording medium may be a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical disk, a hard disk drive, a flash memory, a solid state disk (SSD), and the like. In addition, the computer-readable code or program stored in the computer-readable recording medium may be transmitted through a network connected between the computers.

Hereinafter, a target detection method according to an embodiment of the present invention will be described. In the description of the target detection method according to an embodiment of the present invention, a description overlapping with the above description with respect to the radar apparatus according to an embodiment of the present invention will be omitted.

6 is a view schematically showing a target detection method according to an embodiment of the present invention.

Referring to FIG. 6, in the target detection method according to an exemplary embodiment of the present invention, a target is detected from the radar signal by a process of receiving a radar signal in a detection area (S210) and a constant false alarm rate (CFAR) process (S220). And detecting the target (S220), dividing the detection area into a plurality of operations (S221), individually determining a scale factor for each of the divided detection areas, and determining the constant false alarm rate (CFAR). A step S222 of setting a threshold of processing and a step S223 of detecting a target from a radar signal having an output value larger than the threshold value are included.

Receiving a radar signal in the detection area (S210) receives a radar signal including a target signal and a clutter signal in the detection area for the detection of the target. In this case, in order to predict the distribution of the radar signal, the prediction of the clutter distribution is performed at the end of the 1 bar scan, and the distribution data is predicted by updating the existing data every 1 bar scan. In the case of a radar for detecting a long distance in a sea area where the wave height is constantly changing, since the area of the beam steered to the sea is wide, the sectors are divided in the range direction, for example, by 10 km. The sectors are divided by dwells in the azimuth direction of the radar irradiated in one direction.

As illustrated in FIG. 7, the detection area may be divided into M × N in azimuth and distance directions. For example, there may be a total of 72 clutter sector areas. In the process of estimating the clutter distribution, a radar signal including a target signal and a clutter signal for a detection area is received, and a signal reflected from a target having a large radar reflection area (RCS) in the received radar signal and from a land or an island. The clutter distribution can be predicted by removing the reflected signal.

In the process of setting a threshold (S222), a scale factor is individually determined for each divided detection region to set a threshold for a predetermined false alarm rate (CFAR) process. In this case, the target detection method according to an embodiment of the present invention does not set a threshold using a fixed scale factor, but calculates a scale factor from a predicted clutter distribution. In this case, the scale factor may be individually determined for each detection area divided into a plurality, and this may be determined from the clutter signal extracted for each detection area divided.

Here, the process of setting the threshold (S222) is the case of detecting the target (S220) by detecting the target by the cell average constant false alarm rate (CA CFAR) processing and by the sequential statistical constant false alarm rate (OS CFAR) processing It is divided into the case of detecting the target. In FIG. 8, a target is detected by a cell average constant false alarm rate (CA CFAR) process, and in FIG. 9, a target is detected by a sequential statistical constant false alarm rate (OS CFAR) process.

First, when detecting a target by a cell average constant false alarm rate (CA CFAR) process, the step of setting a threshold (S222) is the process of storing the output value of the clutter signal in a plurality of cells for each divided detection area, the Scanning a plurality of cells to determine an output value of a test cell and an output value of a reference cell, calculating a reference level by averaging the output values of the reference cell, and comparing the output value of the test cell with the reference level Determining a scale factor and multiplying the scale factor by an ambient signal value to set a threshold.

In addition, when detecting a target by a sequential statistical constant alarm rate (OS CFAR) process, the step of setting a threshold (S222) is the process of storing the output value of the clutter signal in a plurality of cells for each divided detection area, the Scanning a plurality of cells, checking an output value of a test cell and an output value of a reference cell, arranging output values of the reference cell in order of magnitude, and selecting an output value having a predetermined rank to calculate a reference level And determining a scale factor by comparing the output value of the test cell with the reference level, and setting a threshold by multiplying the scale factor by an ambient environment signal value.

That is, when detecting a target by a cell average constant false alarm rate (CA CFAR) process and when detecting a target by a sequential statistical constant false alarm rate (OS CFAR) process, the reference level is set in the process of setting a threshold (S222). Only the calculation process is different, and in the process of setting the threshold value (S222), the threshold value is set only by the clutter signal except for the target signal. Here, the process of storing the output value of the clutter signal, the process of confirming the output value of the test cell and the output value of the reference cell, the process of calculating the reference level and determining the scale factor according to an embodiment of the present invention As described above with reference to the threshold setting method of the constant false alarm rate processing, duplicate description thereof will be omitted.

When the scale factor is determined by the above-described process, in step S222 of setting the threshold value, the threshold value is set by multiplying the scale factor by the ambient environmental signal value. Here, the ambient environment signal value is calculated from a plurality of cells in which the output values of the radar signal are arranged along a range direction in the radar signal including both the target signal and the clutter signal.

That is, the output values of the radar signal including both the target signal and the clutter signal may be arranged in a range direction and sequentially stored in a plurality of cells, and the window portion W is shown in FIGS. 8 and 9. As shown in the drawing, at least one cell among a plurality of cells is designated as a test cell T, and a cell located within a predetermined distance from the test cell T is designated as a reference cell R to calculate an ambient environment signal value. do. At this time, the environment signal value is the average value of the output value of the reference cell R with respect to the output value of the radar signal including both the target signal and the clutter signal, or the output value of the reference cell R in order of magnitude. The values may be aligned and selected output values having a predetermined rank. The threshold value may be set by multiplying the ambient signal value thus calculated by the scale factor separately calculated by the above-described process.

In the detecting of the target (S223), the target value is detected by comparing the threshold value with the output value of the test cell T with respect to the output value of the radar signal including both the target signal and the clutter signal. In this case, when the output value of the test cell T has a value larger than the threshold value, the test cell T determines that the output value of the target signal is stored and detects the target. The content of detecting the target by comparing the output value and the threshold value of the test cell T is the same as the configuration generally applied to the constant false alarm rate (CFAR) processing, a detailed description thereof will be omitted.

As described above, according to the target detection method according to the embodiment of the present invention, the distribution of the clutter signal is predicted in an environment in which the clutter signal is changed in fluid, and the false alarm rate required by the radar system according to the predicted result is matched. By adaptively adjusting the scale factor, it is possible to improve the target detection probability.

In addition, the artificial scale factor does not need to be adjusted according to the environment when the radar system is operated, and the target signal is processed so that the influence of the target signal is not reflected on the reference level, thereby enabling more efficient target detection.

In the above, while the preferred embodiment of the present invention has been described and illustrated using specific terms, such terms are only for clearly describing the present invention, and the embodiments of the present invention and the described terms are used in the technical spirit of the following claims. It is obvious that various changes and modifications can be made without departing from the scope of the present invention. Such modified embodiments should not be understood individually from the spirit and scope of the present invention, but should fall within the claims of the present invention.

Claims (8)

Receiving a radar signal in the detection area; And
Detecting a target from the radar signal by a constant false alarm rate (CFAR) process;
The process of detecting the target,
Dividing the detection area into a plurality;
Individually determining a scale factor for each of the divided detection regions and setting a threshold for the constant false alarm rate (CFAR) processing; And
Detecting a target from the radar signal having an output value greater than the threshold. The method according to claim 1,
Dividing the detection area into a plurality of,
Target detection method for dividing the detection area into a plurality of according to the azimuth direction and the distance direction. The method according to claim 1,
And the detection zone comprises a marine zone at which crests vary continuously. Receiving a radar signal in the detection area; And
Detecting a target from the radar signal by a constant false alarm rate processing (CFAR);
The process of detecting the target,
Dividing the detection area into a plurality;
Separately determining a scale factor from the clutter signal extracted for each of the divided detection regions, and setting a threshold of the predetermined false alarm rate processing; And
Detecting a target from the radar signal having an output value greater than the threshold. Receiving a radar signal in the detection area; And
Detecting a target from the radar signal by a cell average constant false alarm rate (CA-CFAR) process;
The process of detecting the target,
Dividing the detection area into a plurality;
Determining a scale factor for each of the divided detection regions and setting a threshold value of the CA-CFAR processing; And
Detecting a target from the radar signal having an output value greater than the threshold. The method according to claim 5,
The setting of the threshold value of the cell average constant false alarm rate (CA-CFAR) processing may include:
Storing an output value of a clutter signal in a plurality of cells for each of the divided detection regions;
Scanning the plurality of cells and checking an output value of a test cell and an output value of a reference cell;
Calculating a reference level by averaging the output values of the reference cells;
Determining a scale factor by comparing the output value of the test cell with the reference level; And
And multiplying the scale factor by an environmental signal value to set a threshold value. Receiving a radar signal in the detection area; And
Detecting a target from the radar signal by an order statistical constant false alarm rate (OS-CFAR) process;
The process of detecting the target,
Dividing the detection area into a plurality;
Determining a scale factor individually for each of the divided detection regions and setting a threshold value of the sequence statistical constant alarm rate (OS-CFAR) process; And
Detecting a target from the radar signal having an output value greater than the threshold. The method according to claim 7,
The process of setting the threshold value of the sequence statistics constant false alarm rate (OS-CFAR) processing,
Storing an output value of a clutter signal in a plurality of cells for each of the divided detection regions;
Scanning the plurality of cells and checking an output value of a test cell and an output value of a reference cell;
Arranging output values of the reference cells in order of magnitude and selecting output values having a predetermined rank to calculate a reference level;
Determining a scale factor by comparing the output value of the test cell with the reference level; And
And multiplying the scale factor by an environmental signal value to set a threshold value.

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