KR101066069B1 - Radar target detection method and apparatus by using variable section size - Google Patents

Abstract

The present invention relates to a radar target detection method and a radar target detection device, wherein the radar target detection method comprises the steps of setting a processing section for the radar received signal, recognizing a target in the processing section based on the signal; Removing the target recognized in the boundary region of the processing section of the target, changing a setting condition of the processing section, and repeating the steps. As a result, the present invention mitigates or prevents detection of false targets in the radar, thereby increasing the detection performance of the radar.

Radar, target, boundary area

Description

Radar target detection method and apparatus using variable processing section size {{RADAR TARGET DETECTION METHOD AND APPARATUS BY USING VARIABLE SECTION SIZE}

The present invention relates to a method and apparatus for detecting a target for each treatment section in a radar.

Radar (radar) is an abbreviation of Radio Detecting And Ranging (Radar) is a radio monitoring device that emits electromagnetic waves, receives the electromagnetic waves reflected from the object and finds the distance, direction, altitude, etc. with the object.

The radar can find out the distance, direction, and altitude of the target by measuring the time of electromagnetic waves reflected back, and is particularly used as a military means for detecting a target. With recent advances in advanced technology, radars are demanding high levels of detection and tracking of targets and missiles in environments such as clutter and jamming.

Accordingly, a radar target detection method capable of mitigating or preventing the detection of a wrong target and accurately detecting a real target may be proposed.

One object of the present invention is to provide a radar target detection method and a radar target detection apparatus capable of mitigating detection of a wrong target.

Another object of the present invention is to provide a radar target detection method and a radar target detection apparatus capable of quickly processing a radar received signal.

In order to achieve the above object of the present invention, the radar target detection method according to an embodiment of the present invention comprises the steps of setting the treatment interval, recognizing the target, removing the target, changing the setting conditions And repeating the steps. The step of setting the processing section sets the processing section for the radar received signal. Recognizing the target recognizes the target in the processing section based on the signal. The step of removing a target removes a target recognized in the boundary region of the treatment section of the target. Changing the setting condition changes the setting condition of the processing section. Repeating steps repeats the above steps.

According to an aspect of the present invention, the boundary region includes first and second boundary regions repeated according to a change of the setting condition. The target to be removed may be recognized in an area obtained by subtracting an overlapping portion of the first and second boundary areas from the first or second boundary area, respectively.

According to another aspect of the present invention, the setting condition is changed to change the size of the processing section or to move the processing section. The setting condition may be changed periodically. The radar target detection method may further include verifying the authenticity of the target.

According to another aspect of the invention, recognizing the target includes calculating and comparing a threshold. The step of calculating a threshold calculates a threshold from the signal. The comparing step compares the threshold and the magnitude of the signal to recognize the target.

In addition, the present invention provides a radar target detection device for realizing the above object. The radar target detection device includes a processing unit and a control unit. The processing unit is configured to distribute the radar received signal according to the processing section and to recognize the target in the processing section as the input value. The control unit removes the target recognized in the boundary region of the processing section of the target, and repeatedly changes the setting conditions of the processing section. The processing unit may be provided in plural and connected in parallel.

The radar target detection method and radar target detection apparatus according to the present invention configured as described above mitigates or prevents detection of false targets in the radar by changing the setting conditions of the processing section and removing the target recognized in the boundary area. This increases the radar detection performance.

 In addition, the radar target detection method can process the radar received signal more quickly by setting the processing section and removing the target recognized in the boundary area. In addition, the radar target detection apparatus can process the radar received signal more quickly as the processing units are connected in parallel.

EMBODIMENT OF THE INVENTION Hereinafter, the radar target detection method and radar target detection apparatus which concern on this invention are demonstrated in detail with reference to drawings. In the present specification, the same or similar reference numerals are assigned to the same or similar configurations in different embodiments, and the description thereof is replaced with the first description. As used herein, the singular forms "a", "an" and "the" include plural forms unless the context clearly indicates otherwise.

1 is a flowchart illustrating a radar target detection method according to the present invention.

Referring to this figure, first, a processing section for a radar received signal is set (S100).

The radar reception signal refers to a signal corresponding to the electromagnetic wave received by the radar. The electromagnetic wave may be, for example, microwave (microwave, 10 cm to 100 cm wavelength). The electromagnetic wave may be transmitted by the radar, may be reflected by the target, and may be received by the radar.

The processing section may be set in plural. The processing section may be set in plural if the signal amount is large according to the amount of radar received signals, and each processing section is formed to partition data corresponding to the received signal into sections. As a result, each treatment section forms a boundary region between adjacent treatment sections. A boundary area is an area in which no surrounding data necessary for recognizing a target based on a certain point does not exist in a corresponding processing section.

Next, the target is recognized in the processing section based on the signal (S200). In step S200 of recognizing the target, for example, a constant false alarm rate (CFAR) algorithm may be applied.

Among the targets to be recognized may include targets recognized in the boundary region of the treatment section (hereinafter referred to as 'boundary target'). The landmark is removed from the target (S300).

The part of the recognized target whose landmark is removed (hereinafter referred to as 'residual target') is marked as a target on a radar device or the like. Any order of detection is performed by setting the processing section (S100), recognition of the target (S200) and landmark removal (S300).

If the target detection of the radar is not terminated by the user or the like, in the next detection, the setting condition of the processing section is changed (S400). As the steps (S100, S200, S300, S400) are repeated in a repeating step, radar target detection is continuously performed.

The radar target detection method may include a step S500 of verifying. Verification step (S500) verifies the authenticity of the target. The verification method can be made, for example, by plot processing of the controller.

FIG. 2 is a detailed flowchart illustrating a step S200 of recognizing the target of FIG. 1, FIG. 3 is a graph showing a radar signal in the boundary region of FIG. 1, and FIGS. 4A and 4B are the process sections of FIG. 1. Conceptual diagrams show examples of changing conditions.

Referring to FIG. 2, the step of recognizing the target (S200) includes calculating a threshold (S210) and comparing (S220).

Computing the threshold value (S210) calculates a threshold value from the signal. The threshold may be calculated, for example, by the Constant False Alarm Rate (CFAR) algorithm.

In step S220, the threshold is compared with the magnitude of the signal to recognize the target. If the magnitude of the signal is greater than the threshold, the signal is treated as a signal to the target, whereby the target is recognized.

An example in which the landmark is recognized will be described with reference to the graph of FIG. 3. The X axis of the graph represents the distance and the Y axis represents the magnitude of the signal.

Boundary areas 101a and 102a are formed between the processing sections 101, 102 and 103.

By not considering the peripheral signal value, the threshold value in each of the boundary regions 101a and 102a may be constant according to the distance. On the contrary, the threshold 104 of the processing sections 101, 102 and 103 except for the boundary areas 101a and 102a may change with distance in consideration of the peripheral signal values.

Referring to this graph, the residual target 106 is recognized in one of the processing sections 102 and the landmark 107 is recognized in one of the boundary regions 102a. In the boundary region 102a where the landmark 107 was recognized, a portion of the received signal 105 larger than the threshold 104a appears. Thereby the landmark 107 is recognized as a target at that point.

If the threshold 104b is obtained in the boundary region 102a assuming that a signal existing in the adjacent processing section 103 can be referred to, the magnitude of the signal 105 may appear smaller than the threshold as shown. Thus, the landmark 107 is determined to be a mistake. Indeed, most landmarks are erratic, which serves as a major impediment to radar detection.

Referring back to FIG. 2, detection of the wrong target may be mitigated or prevented as the landmark is removed in step S300 of removing the target.

In the step S400 of changing the setting condition of the processing section, the setting condition is changed to change the size of the processing section or move the processing section. Setting conditions can be changed periodically. By changing the size of the processing section or moving the processing section, the position of the boundary area changes for each detection.

The boundary region includes first and second boundary regions repeated according to the change of the setting condition. The first and second boundary regions are boundary regions of respective detections formed in successive detections, respectively.

Referring to FIG. 4A, the size of the processing section is changed for each detection. The first processing sections 111, 112, and 113 formed in the first detection are changed in size in the second processing sections 121, 122, and 123 formed in the second detection, and the second processing sections 121, 122 and 123 are changed back to the first processing sections 111, 112 and 113 in the third detection.

The first boundary regions 111a and 112a formed in the first detection are changed to the second boundary regions 121a and 122a in the second detection.

Referring to FIG. 4B, the processing section is moved for each detection. The first processing sections 211, 212, 213 formed in the first detection are moved to the second processing sections 221, 222, 223 in the second detection. The second processing sections 221, 222, and 223 are restored to the first processing sections 211, 212, and 213 at the third detection.

The landmarks 106 (refer to FIG. 3) recognized by the change of the setting conditions of the processing section as described above are removed only in the case of a typographical error.

The case where landmark 106 is real will be described by way of example. In the first detection, landmark 106 can be recognized. If the recognized landmark is a real target rather than a miss target, it can be recognized as a residual target (see FIG. 3) in the next detection. Therefore, the missed real target can be prevented.

Referring to FIG. 2 again, the target to be removed may be recognized in an area obtained by subtracting the overlapping portions of the first and second boundary areas from the first or second boundary areas, respectively. This may prevent the recognized target from being removed at the overlapping portions of the first and second boundary regions.

The size of the treatment section may be determined such that the overlapping portions of the first and second boundary regions are as far as possible. This mitigates or prevents the effects of near-field strong terrain clutter, which further mitigates the detection of false targets.

Hereinafter, an example of a radar target detection method using the CFAR algorithm and the CFAR algorithm as an example of the method of recognizing the target will be described.

5 is a conceptual diagram of a Minimum Cell Average (MCA) -Constant False Alarm Rate (CFAR) algorithm, and FIG. 6 is a flowchart illustrating a method of detecting a radar target by applying the CFAR algorithm of FIG. 5.

The CFAR algorithm detects targets properly while maintaining a constant false alarm under noise, clutter or jamming conditions. Among the CFAR algorithms, adaptive thresholding maintains a constant false alarm rate by varying the threshold depending on the radar environment such as noise or clutter around the test cell.

In the adaptive threshold method, the average of noise or flutter included in a certain number of cells around the test cell is used to multiply the weight corresponding to a given false alarm rate and use it as a threshold. do.

The MCA-CFAR algorithm takes a minimum in two cells spaced apart by a pulse width within a constant window around the test cell.

Equations (1), (2) and (3) are equations applied when a signal is processed in one processing section using the MCA-CFAR algorithm.

i = 1, .., D, j = 1, ..., R,

A (i, j): input data

H (i, j): threshold for A (i, j) for target detection

i: Doppler cell

j: index of distance cell

R: Number of distance cells of input data

D: Doppler cell number of input data

h: relative threshold or proportional factor that determines false alarm rate

n: average window size for noise estimation

m: Window size for removing target signal samples in noise estimation

N: size of treatment section

Referring to FIG. 5, an array A consisting of absolute values of the optimum filter outputs becomes an input of the MCA-CFAR. H (i, j) for determining A (i, j) of a test cell is based on n averages of n cells (n / 2 left and n / 2 right) of the minimum of n cells It is obtained by multiplying by h. As a result, when A (i, j) is larger than H (i, j), the object at the position corresponding to the test cell is recognized as a target.

Equation (1) is a formula for obtaining a threshold value for a test cell capable of obtaining n data around a test cell, and Equation (2) and (3) are obtained when there are no n data around the test cell. The threshold is calculated for each (n + m) / 2 data at both ends.

Equations (4) and (5) are equations applied when signal processing data is processed in a plurality of processing sections.

Ns: Size of each treatment section (number of samples distributed in each treatment section)

Equation (4) is the same as Equation (1), but Equation (5) determines the H value of the processing section boundary area where the average noise around the test cell cannot be obtained. Obtain the average using the minimum values.

The size of the processing section may be determined by the signal processing capability of the digital signal processor for signal processing. The size of the treatment section can be determined by equation (6).

b = a + (n + m) / 2

a: the size of any processing section

b: size of one processing section

Hereinafter, a method of eliminating erroneous targets when signal processing is performed by alternately applying sizes a and b to two processing sections will be described with reference to FIG. 6.

First, when the size of the processing section is set to each, the boundary area information is stored in the first variable tz1 and the second variable tz2 and the overlapping boundary area information in each detection is stored in the third variable tz12 (S701). .

Section sizes are alternately set for each detection (S702) and CFAR is applied (S703) to recognize the target (S704). Next, in each signal processing result, a target that does not belong to the third variable tz12 among the target signals of the boundary region is removed (S705). Even if all target signals generated in the boundary area are removed through this process, the target signals that may have been removed together at this time may not be entered into the boundary area in the next detection and finally detected as targets through the controller's plot processing (S706). have.

Hereinafter, an example of a radar target detection apparatus to which the method for recognizing the target is applied will be described. 7 is a conceptual diagram illustrating an embodiment of a radar target detection apparatus according to the present invention.

The radar target detection apparatus 800 includes a processing unit 801 and a control unit 802.

The processing unit 801 is configured to distribute the radar received signal according to the processing section and to recognize the target in the processing section as the input value. Referring to this figure, the processing units 801a, 801b, and 801c may be provided in plural and connected in parallel. The treatment section may be provided in plurality.

The plurality of processing units 801a, 801b, and 801c may be formed to recognize targets in the plurality of processing sections, respectively. The method of recognizing a target may be, for example, a CFAR algorithm.

The control unit 802 is configured to remove a target recognized in the boundary region of the processing section among the targets, and to repeatedly change the setting condition of the processing section. The setting condition may be changed to change the size of the processing section or to move the processing section.

The radar target detection apparatus 800 may include a display device 803. The display device 802 is electrically connected to the control unit 802 and controlled by the control unit 802. The display device 803 may be formed to display image information about the target. This allows the user to visually recognize radar information about the target.

The radar target detection method and the radar target detection apparatus according to the present invention as described above are not limited to the configuration and method of the embodiments described above, the embodiments are all or part of each embodiment so that various modifications can be made It may alternatively be configured in combination.

1 is a flow chart showing a radar target detection method according to the present invention.

FIG. 2 is a flowchart detailing the step of recognizing the target of FIG.

3 is a graph showing a radar signal in the boundary region of FIG. 1.

4A and 4B are conceptual views showing examples of changing setting conditions of a processing section of FIG. 1;

5 is a conceptual diagram of a minimum cell average (MCA) -constant false alarm rate (CFAR) algorithm.

6 is a flow chart illustrating a method of detecting a radar target by applying the CFAR algorithm of FIG.

7 is a conceptual diagram illustrating an embodiment of a radar target detection apparatus according to the present invention.

Claims (9)

Setting a plurality of processing sections for the signal so that the signal received from the radar is partitioned and processed; Recognizing a target in the processing sections based on the signal; Removing a target recognized in a boundary area formed between adjacent processing sections among the targets; Changing setting conditions of the processing sections; And And repeating the above steps. The method of claim 1, And the boundary area includes first and second boundary areas formed before and after the change point of the setting condition. The method of claim 2, And the target to be removed is recognized in an area obtained by subtracting an overlapping portion of the first and second boundary areas from the first or second boundary area, respectively. The method of claim 1, And the setting condition is changed to change the size of the processing section or to move the processing section. The method of claim 1, The setting condition is a radar target detection method characterized in that it is changed periodically. The method of claim 1, Radar target detection method further comprises the step of verifying the authenticity of the target. The method of claim 1, Recognizing the target, Calculating a threshold from the signal; And And comparing the threshold with the magnitude of the signal to recognize the target. A processing unit configured to set a plurality of processing sections for the signal so that the signal received from the radar is processed and recognize the target in the processing sections using the signal as an input value; And And a control unit for removing a target recognized in a boundary area formed between adjacent processing sections among the targets, and repeatedly changing a setting condition of the processing sections. The method of claim 8, The processing unit is provided with a plurality so as to correspond to each of the processing section, the radar target detection device, characterized in that connected in parallel.

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