KR102421093B1 - Apparatus for Cancelling Interference Plot based on Signal Processing Gain, and Method thereof - Google Patents

Abstract

An apparatus for removing an interference signal plot based on a signal processing gain according to an embodiment of the present invention is an apparatus for removing an interference signal plot of a radar system, a pulse generator generating a transmission pulse including transmission information, and transmitting the generated transmission pulse through an antenna A frequency modulator that up-converts a frequency for transmission, a frequency modulator that amplifies the modulated signal to radiate through the antenna, and amplifies the received signal received through the antenna after the transmitted signal is reflected to the target A frequency demodulator that down-converts a frequency demodulator, a base signal demodulator that digitally demodulates a frequency-demodulated received signal through down-frequency change into a baseband signal, and a signal processing step when a plot is detected in the baseband demodulated received signal. It includes a target detection unit that removes the interference signal plot based on the comparison result of the power difference and the signal processing gain and detects an actual target.

Description

Apparatus for Canceling Interference Plot based on Signal Processing Gain, and Method thereof

The present invention relates to an apparatus and method for removing an interference signal plot based on a signal processing gain, and more particularly, an apparatus for removing a plot generated by an interference signal based on a signal processing gain for each step without providing a separate false plot monitoring period. and methods.

In the prior art, in order to check that an external interference signal is coming in, there is a section for only receiving without transmission, monitoring the external interference signal and avoiding the frequency when there is an external interference signal or SLC (SideLobe Cancelling) or ABF (Adaptive Beam Forming), etc. It was possible to remove the interference signal by applying it.

The SLC (SideLobe Cancelling) method, which is one of the existing methods, first collects pure external interference signals in a PLP (Passive Listening Period) in a monopulse radar system. The PLP is a section in which a radar pulse is transmitted without transmitting a radar pulse to detect an external jamming signal existing in front of a section to receive a radar reflected wave or to measure internal thermal noise. The jamming signal is detected with the signal collected from this PLP, and the weight is adaptively determined. In this way, the weight determined by the PLP is applied and combined to the radar reflected wave signal of the main/auxiliary channel obtained after transmitting the pulse from the PLP to make the output with the side-lobe jammer removed.

In the SLC (SideLobe Cancelling) method, the radar interference signal is removed by first setting the PLP (Passive Listening Period) section separately, then determining the external interference signal and avoiding the frequency. Nevertheless, there are cases where the external interference signal continues to come in the form of a continuous wave (CW), but since it may intermittently come in in the form of a pulse, there were many cases where reception was not possible in the PLP section.

In addition, there is a method of removing the external interference signal, such as frequency avoidance, but in order to avoid the frequency, it is necessary to first determine that the external interference signal has been received, but unless it enters the PLP section, it is difficult to detect.

Another existing method, the Adaptive Sidelobe Blanking (adaptive SLB: ASB) method, is a method that enables Sidelobe Blanking (SLB) even in an interference environment. At the same time, it effectively blocks the signal coming into the side lobe. When LCMV (Linearly Constrained Minimum Variance) is used as the Adaptive Beam Forming (ABF) algorithm, an adaptive SLB suitable for this has also been proposed. This modifies the covariance matrix so that the signal of the SLB channel satisfies the direction constraint of the LCMV, and a normalized output is obtained from it so that the side-lobe signal is effectively blocked.

Even if an external interference signal is detected according to the conventional method described above and SLC or ABF technique is applied, this is a method to form a null in the beam and remove it when it is detected in a direction other than the direction in which the beam is emitted. I have a problem that doesn't work well.

An object of the present invention is to provide an apparatus and method for removing an interference signal plot based on a signal processing gain without providing a separate monitoring section in order to remove a false plot generated by an external interference signal in a radar.

Other objects not specified in the present invention may be additionally considered within the scope that can be easily inferred from the following detailed description and effects thereof.

An apparatus for removing an interference signal plot based on a signal processing gain according to an embodiment of the present invention comprises: a pulse generator for generating a transmission pulse including transmission information; a frequency modulator for performing frequency modulation for up-converting the frequency to transmit the generated transmission pulse through an antenna, and amplifying the modulated signal to be radiated through the antenna; a frequency demodulator that amplifies the received signal received through the antenna after the transmitted signal is reflected by the target and performs frequency modulation for down-converting the frequency of the received signal; a base signal demodulator for digitally demodulating the frequency-demodulated received signal through the downlink frequency change into a baseband signal; and a target detector configured to remove an interference signal plot and detect an actual target based on a comparison result of a signal processing gain and a power difference for each signal processing step when a plot is detected from the baseband demodulated received signal.

In an embodiment, the target detector includes: a pulse compression unit for performing pulse compression in a distance cell by applying a matching filter according to a transmission waveform for each pulse to a received signal aligned in a distance direction for each pulse; a Doppler filter that performs Doppler processing on the pulse-compressed received signal through a Fourier transform according to a pulse signal for each distance cell in order to remove clutter mixed with the received signal; a CFAR unit that calculates hits by performing 1D-CFAR (Constant False Alarm Rate) on a distance cell in order to maintain a false occurrence rate in the Doppler-processed signal; a target extraction unit for clustering the hits passing through the CFAR unit to form a single plot, and extracting various target information from the formed plot; and an interference plot removing unit that compares the power of each pulse as a result of the pulse compression and removes the received signal as an interference signal plot based on an external interference signal when it exceeds a preset error range.

As an embodiment, the interference plot removal unit RMS size (RMS) for each pulse among the signal magnitudes in the corresponding distance cells in the previous pulse compression result based on the signal magnitude (P2) in the distance cell and the Doppler cell detected among the detected plot information It is possible to calculate P1).

As an embodiment, when the difference between the signal magnitude P2 and the pulse RMS magnitude P1 in the Doppler cell exceeds a preset signal processing gain error range, the interference plot removing unit generates the plot by an external interference signal. It is possible to treat it as

As an embodiment, if the difference between the signal magnitude P2 and the pulse RMS magnitude P1 in the Doppler cell is within a preset signal processing gain error range, the plot is determined to be generated by an actual target. It is possible to do processing.

According to another embodiment of the present invention, a method for removing an interference signal plot based on a signal processing gain is a method for removing an interference signal plot of a radar system, the method comprising: generating a transmission pulse using a baseband signal including transmission information; up-converting to a frequency higher than the frequency of the baseband signal, amplifying and transmitting the signal; receiving a signal reflected by a target, and amplifying the received signal; down-converting the received signal to a frequency lower than the frequency of the received signal and then demodulating the received signal into the baseband signal; and when a plot is detected from the baseband demodulated received signal, removing the interference signal plot and detecting an actual target based on the comparison result of the signal processing gain and the power difference for each signal processing step.

In an embodiment, the step of detecting the actual target may include: performing pulse compression in a distance cell by applying a matching filter according to a transmission waveform for each pulse to a received signal aligned in a distance direction for each pulse; performing Doppler processing on the pulse-compressed received signal through a Fourier transform according to a pulse signal for each distance cell in order to remove clutter mixed with the received signal; performing a CFAR performing step of calculating hits by performing 1D-CFAR (Constant False Alarm Rate) on a distance cell in order to maintain a false occurrence rate in the Doppler-processed signal; forming a single plot by clustering the hits that have passed through the CFAR unit, and extracting various target information from the formed plot; and comparing the power for each pulse as a result of the pulse compression and removing the interference plot by judging the received signal as an interference signal plot based on an external interference signal when it exceeds a preset error range.

As an embodiment, the step of removing the interference plot may include the RMS magnitude (P1) for each pulse among the signal magnitudes in the corresponding distance cell in the previous pulse compression result based on the signal magnitude (P2) in the Doppler cell detected among the detected plot information. ) can be calculated.

As an embodiment, in the step of removing the interference plot, when the difference between the signal magnitude P2 and the pulse RMS magnitude P1 in the Doppler cell exceeds a preset signal processing gain error range, the plot is applied to the external interference signal. It is possible to treat it as caused by

As an embodiment, in the step of removing the interference plot, when the difference between the signal magnitude P2 and the pulse RMS magnitude P1 in the Doppler cell is within a preset signal processing gain error range, the plot is generated by an actual target It is possible to treat it as

In an embodiment, the detected plot information may include at least one of a Doppler value, a detected distance/Doppler cell index, a signal-to-noise ratio (SNR), and a monopulse angle (azimuth/elevation).

An apparatus and method for removing an interference signal plot based on signal processing gain according to an embodiment of the present invention uses signal processing gain information for each stage even without a separate monitoring section in order to remove a false plot generated by an external interference signal from a radar to eliminate false plots.

In addition, the signal processing gain-based interference signal plot removal apparatus and method according to an embodiment of the present invention determines whether a false plot is a false plot in consideration of the step-by-step gain information acquired in the signal processing process, so that the false plot is quickly obtained without consuming additional calculation time. cognition can be judged.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a schematic diagram of an apparatus for removing an interference signal plot based on a signal processing gain according to an embodiment of the present invention.
FIG. 2 is a detailed schematic view of the target detection unit shown in FIG. 1 .
3 is a flowchart of a method for removing an interference signal plot based on a signal processing gain according to an embodiment of the present invention.
4 is a detailed flowchart of the target detection step of FIG. 3 .
FIG. 5 is a detailed flowchart of the step of removing the interference signal plot of FIG. 4 .
6 is a diagram illustrating a radar measurement timing when an interference signal plot is removed according to an embodiment of the present invention.
7 is a diagram illustrating a result of a radar reception signal after frequency down-conversion and digital demodulation processing in a baseband when an interference signal plot is removed according to an embodiment of the present invention.
FIG. 8 shows a result of generating a constant transmission signal for each pulse of the signal shown in FIG. 7 and generating a target reflected reception signal at almost the same position for each pulse.
9(A) shows the rearranged distance-pulse form of the received signal shown in FIG. 7 as 2D data, respectively, and FIG. 9(B) is the received signal shown in FIG. Compressed results are shown.
10(A) is the result of Doppler processing on the pulse axis of the pulse compression result shown in FIG. 9(B), respectively, and 10(B) is the method of FIG. 5 for target information among the results shown in FIG. 10(A). shows the result of removing the false plot according to

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments published below, but may be implemented in various different forms, and only these embodiments allow the publication of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular.

In the present specification, terms such as “first” and “second” are for distinguishing one component from other components, and the scope of rights should not be limited by these terms. For example, a first component may be termed a second component, and similarly, a second component may also be termed a first component.

In the present specification, identification symbols (eg, a, b, c, etc.) in each step are used for convenience of description, and identification symbols do not describe the order of each step, and each step is clearly Unless a specific order is specified, the order may differ from the specified order. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

In this specification, expressions such as “have”, “may have”, “include” or “may include” indicate the presence of a corresponding feature (eg, a numerical value, function, operation, or component such as a part). and does not exclude the presence of additional features.

In addition, the term '~ unit' as used herein means software or a hardware component such as a field-programmable gate array (FPGA) or ASIC, and '~ unit' performs certain roles. However, '-part' is not limited to software or hardware. '~unit' may be configured to reside on an addressable storage medium or may be configured to refresh one or more processors. Thus, as an example, '~' denotes components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data structures and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'.

The present inventor made a proposed invention from the need for a method for removing a false plot when a false plot occurs due to an interference signal in an actual radar reception signal section other than the PLP section.

Hereinafter, a configuration of an apparatus for removing an interference signal plot based on a signal processing gain according to an embodiment of the present invention will be described in detail with reference to the related drawings.

1 is a schematic diagram of an apparatus for removing an interference signal plot based on a signal processing gain according to an embodiment of the present invention, and FIG. 2 is a detailed schematic diagram of the target detection unit shown in FIG. 1 . 3 is a flowchart of a signal processing gain-based interference signal plot removal method according to an embodiment of the present invention, FIG. 4 is a detailed flowchart of the target detection step of FIG. 3, and FIG. 5 is the interference signal plot removal step of FIG. This is a detailed flowchart.

1 to 5, the signal processing gain-based interference signal plot removal apparatus 100 according to an embodiment of the present invention includes a pulse generator 110 that generates a transmission pulse including transmission information, and the generation A frequency modulation unit 120 that up-converts the frequency to transmit the transmitted transmission pulse through the antenna 130 and amplifies the modulated signal to be radiated through the antenna 130, and the transmitted signal The frequency demodulator 140 amplifies the received signal received through the antenna 130 after target reflection and performs frequency modulation for down-converting the frequency of the received signal, and the frequency-demodulated received signal through the down-frequency change. The base signal demodulator 150 digitally demodulates the band signal, and when a plot is detected in the baseband demodulated received signal, the interference signal plot is removed based on the comparison result of the signal processing gain and the power difference for each signal processing step, and the actual and a target detection unit 160 for detecting a target.

The signal processing gain-based interference signal plot removal apparatus 100 is a signal processing method for determining whether the detected plot information is due to an actual target or an external signal when an external interference signal is generated in a radar using a pulse.

The signal processing gain-based interference signal plot removal apparatus 100 performs pulse compression and Doppler processing in the process of processing a radar received signal as a false plot removal method using signal processing gain information for each step of the plot, and then hits a hit through CFAR. After generating and extracting the plot through clustering, it is possible to determine whether the plot is an actual target or a false plot using signal processing gain information for each step of the plot information.

Since the signal processing gain-based interference signal plot removal apparatus 100 is in sync with the pulse in the case of the received signal reflected by the actual target, the received signal size is constant, so that the power of the Doppler processing result compared to the pulse compression result power increases by the signal processing gain However, in the case of a received signal due to an external interference signal, the power difference appears randomly because it is input irrespective of the pulse. By using these characteristics, it is possible to determine whether the plot is a plot by an actual target or a plot by an interference signal.

The target detection unit 160 includes a pulse compression unit 161 that performs pulse compression in a distance cell by applying a matching filter according to a transmission waveform for each pulse to a received signal aligned in the distance direction for each pulse, and a clutter rotting in the received signal. A Doppler filter 162 that performs Doppler processing on the pulse-compressed received signal through a Fourier transform according to a pulse signal for each distance cell in order to remove the signal, and a distance cell in order to maintain a false rate in the Doppler-processed signal. The CFAR unit 163 that calculates hits by performing 1D-CFAR (Constant False Alarm Rate), and clusters the hits that have passed through the CFAR unit 163 to form a single plot, and collects various target information from the formed plot. Interference plot removal unit 165 that compares the target extraction unit 164 to extract and the pulse compression result and the power of each pulse and removes the received signal as an interference signal plot by an external interference signal when it exceeds a preset error range includes Here, the hit represents a result calculated through the CFAR unit.

CFAR (Constant False Alarm Rate) is an algorithm that is used to prevent false alarms by dividing frames without fixing the threshold value so as not to notify the target of an error, and can find out the location of the target. Therefore, CFAR (Constant False Alarm Rate) is used to increase the detection probability while maintaining a constant false alarm rate in a clutter background environment.

The interference plot removal unit 165 calculates the RMS magnitude (P1) for each pulse among the signal magnitudes in the corresponding distance cell from the previous pulse compression result based on the signal magnitude (P2) in the Doppler cell detected among the detected plot information. Do (S1761 ~ S1762).

The interference plot removing unit 165 is configured to display the plot generated by an external interference signal when the difference between the signal magnitude P2 and the pulse RMS magnitude P1 in the Doppler cell exceeds a preset signal processing gain error range. It is processed as one (S1763 ~ S1765).

The interference plot removing unit 165 processes the plot as generated by the actual target when the difference between the signal magnitude P2 in the Doppler cell and the pulse RMS magnitude P1 is within a preset signal processing gain error range. Do (S1763 ~ S1765).

An apparatus and method for removing an interference signal plot based on a signal processing gain according to embodiments of the present invention will be described in more detail with reference to FIGS. 1 to 8 .

1 and 3, a transmission pulse included in a radar system (not shown) is generated (S110), a frequency is up-converted and amplified to transmit, and a signal reflected by a target is amplified and frequency down-converted. After that, it means performing digital demodulation processing of a signal in the baseband and signal processing for target detection (S120 ~ S170). At this time, the signal received from the antenna 130 of the radar system may enter when the external interference signal is in the same frequency band in addition to the transmitted pulse signal being reflected and received by the target.

6 is a diagram showing the system timing of the radar system, and when the radar system emits a beam, the front part has a PLP (Passive Listening Period) section to check the external interference signal by performing only reception without transmission, and then the pulse It indicates the timing of repeating transmission/reception for each.

Referring to FIG. 7 , the result after frequency downconversion and digital demodulation processing in the baseband is shown as an example, the horizontal axis means the number of samples on the time axis, and the pulse is periodically transmitted you can see A signal received after being reflected by an actual target is periodically received for each pulse, and a signal generated regardless of a pulse in the middle means a signal received by an external interference signal.

FIG. 8 shows the signal shown in FIG. 7 for each pulse, and shows that a transmission signal is constantly generated for each pulse, and a signal reflected by a target and received is generated at almost the same position for each pulse. However, it is shown that the signal received by the external interference signal is randomly generated because it is not synchronized with the pulse.

2 and 4, a process of detecting a plot by signal processing a received signal by a radar system to which an apparatus and method for removing an interference signal plot based on a signal processing gain according to an embodiment of the present invention is applied is shown.

The pulse compression unit 161 receives the received signal RAW_DATA(Nr, Npulse) for each pulse and is data aligned in the distance direction, and applies a matching filter (Hf) according to the transmission waveform to each pulse to first compress the pulse in the distance cell ( PC OUT) is performed (S171), and the process is shown in Equation 1 below.

In Equation 1, fft represents Fast Fourier Transform, RAW_DATA(Nr,Npulse) represents a received signal, PC OUT represents pulse compression, Hf represents a matching filter, and ifft represents inverse high speed Represents an Inverse Fast Fourier Transformation.

The Doppler filter 162 forms a Doppler filter (Doppler process) through a Fourier transform according to a pulse for each distance cell of the pulse-compressed signal (S172), and the process is shown in Equation 2.

In Equation 2, DFB OUT represents a Doppler filter bank.

The CFAR unit 173 may represent a pulse-compressed and Doppler-processed signal as a 2D cell on distance-Doppler, and performs 1D-CFAR (Constant False Alarm Rate) on the distance cell to maintain a constant false alarm rate (S173). ). Hits passing through the CFAR unit 173 are formed into a single plot through clustering (S174), and various target information required from the plot is extracted (S175). Plot information (PLOT_INFO) includes information necessary for detection, such as distance, Doppler, detected distance/Doppler cell index, signal-to-noise ratio (SNR), and monopulse angle (azimuth/elevation).

FIG. 5 shows a process of determining whether the plot PLOT_INFO is detected after signal processing, whether it is a signal reflected by an actual target or a plot caused by an external interference signal.

Based on the signal magnitude (P2) in the detected distance cell (Rin) and Doppler cell (Din) among the plot information (PLOT_INFO), each pulse of power in the corresponding distance cell (Rin) in the previous signal processing step, that is, the pulse compression result The RMS power P1 is calculated and compared according to Equation 3 (S1761 to S1764).

In case of being reflected by an actual target, the power of each pulse as a result of pulse compression will be almost the same, so the RMS power does not differ much from the power of each pulse. Therefore, compared with P2 after taking RMS, it does not increase as much as the signal processing gain. At this time, the signal processing gain (DFB_GAIN) to be compared is determined by the number of pulses and the shape of the Doppler window (W _i ) used.

In the case of a signal reflected by an actual target, even if straddling between Doppler cells is taken into account, when calculated according to Equation 4, the power difference (P2-P1) for each signal processing step is approximately the signal processing gain DFB_GAIN ± 3dB.

If the plot deviates from this, it is regarded as generated by an external interference signal (S1765), and the frequency of occurrence of false plots at the corresponding frequency is counted and used for frequency avoidance.

9(A) shows the rearranged distance-pulse form of the received signal shown in FIG. 7 as 2D data, respectively, and FIG. 9(B) is the received signal shown in FIG. Compressed results are shown. 10(A) is the result of Doppler processing on the pulse axis of the pulse compression result shown in FIG. 9(B), respectively, and 10(B) is the method of FIG. 5 for target information among the results shown in FIG. 10(A). shows the result of removing the false plot according to

A result of removing a false plot by an external interference signal according to an apparatus and method for removing an interference signal plot based on a signal processing gain according to embodiments of the present invention will be described in detail with reference to FIGS. 9(A) to 10(B).

FIG. 9(A) shows the distance-pulse type 2D data by rearranging the received signals shown in FIG. 7 for example. The signal reflected by the target is so small that it cannot be seen before accumulation, but an external interference signal is received as an example. FIG. 9(B) shows a result of pulse compression of the received signal shown in FIG. 9(A) in a distance cell.

FIG. 10(A) shows the result of Doppler processing on the pulse axis on the pulse-compressed result in FIG. 9(B), which means that CFAR and target information are displayed as red dots after extraction. When pulse compression and Doppler processing are performed, it can be seen that the signal received by the actual target is not visible in RAW DATA because the signal is accumulated, but appears in the position indicated by the red circle after accumulation.

However, the signal received by the external interference signal may also be accumulated and sometimes appear stochastic, and the red dots displayed in addition to the red circle are false plots targeted by the external interference signal.

FIG. 10(B) shows the result of removing the false plot after performing the process shown by schematizing each target information in FIGS. 2 and 4 among the results shown in FIG. 10(A). Among the plots shown in FIG. 10(A), if the difference between the power in the stage before the Doppler processing and the power magnitude in the stage after the Doppler processing is similar to the signal processing gain, it is regarded as a plot by the actual target, and if it is out of the range, it is false. It means that only the plot received by the actual target remains as a result of judging by the plot and removing it.

By periodically observing this, even if it is an external interference signal that is not detected in the PLP section, it is possible to check the frequency of occurrence of false plots to determine whether there is an external interference signal. Based on this, it can be used to select an operating frequency with a low external interference signal have.

An apparatus and method for removing an interference signal plot based on a signal processing gain according to an embodiment of the present invention is applicable to a pulse Doppler radar for detecting/tracking a target including a drone detection radar.

In addition, the apparatus and method for removing an interference signal plot based on signal processing gain according to an embodiment of the present invention is expected to be possible for a sonar sensor for detection, etc. in addition to a system using radio waves.

In addition, the signal processing gain-based interference signal plot removal apparatus and method according to an embodiment of the present invention is a step-by-step method when an external interference signal is received outside of an interference signal detection period (PLP) when false plots are generated. Falsehood can be reduced by determining whether the plot is a received plot generated from an actual target or a plot generated by an external interference signal using the signal processing result gain information.

In addition, the signal processing gain-based interference signal plot removal apparatus and method according to an embodiment of the present invention determines whether a false plot is a false plot in consideration of the step-by-step gain information in the existing signal processing process, so it is quickly determined whether the plot is a false plot without increasing the calculation time. can judge

In addition, the signal processing gain-based interference signal plot removal apparatus and method according to an embodiment of the present invention monitors the frequency of occurrence of false plots at the used frequency without a separate PLP section when it is possible to determine whether the plot is due to an external interference signal. Thus, it can be applied to frequency avoidance.

Even though all the components constituting the embodiment of the present invention described above are described as being combined or operated in combination, the present invention is not necessarily limited to this embodiment. That is, within the scope of the object of the present invention, all of the components may operate by selectively combining one or more. In addition, all of the components may be implemented as one independent hardware, but some or all of the components are selectively combined to perform some or all functions of the combined components in one or a plurality of hardware program modules It may be implemented as a computer program having In addition, such a computer program is stored in a computer readable media such as a USB memory, a CD disk, a flash memory, etc., read and executed by a computer, thereby implementing an embodiment of the present invention. The computer program recording medium may include a magnetic recording medium, an optical recording medium, and the like.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes and substitutions are possible within the scope that does not depart from the essential characteristics of the present invention by those of ordinary skill in the art to which the present invention pertains. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are for explanation rather than limiting the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: signal processing gain-based interference signal plot removal device
110: pulse generator
120: frequency modulator
130: antenna
140: frequency demodulator
150: base signal demodulator
160: target detection unit

Claims (13)

In the radar system interference signal plot removal device,
a pulse generator for generating a transmission pulse including transmission information;
a frequency modulator for performing frequency modulation for up-converting the frequency to transmit the generated transmission pulse through an antenna, and amplifying the modulated signal to be radiated through the antenna;
a frequency demodulator that amplifies the received signal received through the antenna after the transmitted signal is reflected by the target and performs frequency modulation for down-converting the frequency of the received signal;
a base signal demodulator for digitally demodulating a frequency-demodulated received signal through down-conversion of a frequency of the received signal into a baseband signal; and
When a plot is detected from the baseband demodulated received signal, a target detector for removing an interference signal plot and detecting an actual target based on a comparison result of a signal processing gain and a power difference for each signal processing step;
The target detection unit includes: a pulse compression unit for performing pulse compression in the distance cell by applying a matching filter according to the transmission waveform for each pulse to the received signal aligned in the distance direction for each pulse; a Doppler filter that performs Doppler processing on the pulse-compressed received signal through a Fourier transform according to a pulse signal for each distance cell in order to remove clutter from the received signal; a CFAR unit that calculates hits by performing 1D-CFAR (Constant False Alarm Rate) on a distance cell in order to maintain a false occurrence rate in the Doppler-processed signal; a target extraction unit for clustering the hits passing through the CFAR unit to form a single plot, and extracting various target information from the formed plot; and an interference plot removing unit that compares the power of each pulse as a result of the pulse compression and removes the received signal as an interference signal plot by an external interference signal when it exceeds a preset error range,
The interference plot removing unit is a corresponding distance cell from the previous pulse compression result based on the signal magnitude P2 in the detected distance cell Rin and the Doppler cell Din among the detected plot information, and the signal magnitude P2. Calculate the RMS magnitude (P1) for each pulse among the signal magnitudes at (Rin), respectively, and calculate the signal processing gain (DFB_GAIN) determined by the number of pulses and the shape of the Doppler window (Wi) used,
When the power difference (P2-P1) for each signal processing step is calculated within a preset error range based on the signal processing gain (DFB_GAIN), it is considered to be reflected by the actual target, and the power difference for each signal processing step ( If P2-P1) is calculated to be outside the preset error range based on the signal processing gain (DFB_GAIN), it is considered to be reflected by the external interference signal, and the frequency is avoided by counting the frequency of occurrence of the interference signal plot at the corresponding frequency Signal processing gain-based interference signal plot removal device, characterized in that used for. delete delete delete delete According to claim 1,
The signal processing gain-based interference signal plot removal apparatus, characterized in that the magnitude of the predetermined signal processing gain is within a predetermined error range. A method of removing an interference signal plot of a radar system, the method comprising:
generating a transmission pulse using a baseband signal including transmission information;
up-converting to a frequency higher than the frequency of the baseband signal, amplifying and transmitting the signal;
receiving the received signal reflected by the target, and amplifying the received signal;
down-converting the received signal to a frequency lower than the frequency of the received signal and then demodulating it into the baseband signal; and
When a plot is detected in the baseband demodulated received signal, removing the interference signal plot and detecting an actual target based on the comparison result of the signal processing gain and the power difference for each signal processing step;
The step of detecting the actual target may include: performing pulse compression in a distance cell by applying a matching filter according to a transmission waveform for each pulse to a received signal aligned in a distance direction for each pulse; performing Doppler processing on the pulse-compressed received signal through a Fourier transform according to a pulse signal for each distance cell in order to remove clutter from the received signal; CFAR performing step in which a CFAR unit calculates hits by performing 1D-CFAR (Constant False Alarm Rate) on a distance cell in order to maintain a false occurrence rate in the Doppler-processed signal; forming a single plot by clustering the hits that have passed through the CFAR unit, and extracting various target information from the formed plot; and comparing the power of each pulse as a result of the pulse compression and removing the interference plot by judging the received signal as an interference signal plot by an external interference signal when it exceeds a preset error range,
In the step of removing the interference plot, the signal magnitude P2 in the distance cell Rin and the Doppler cell Din detected among the detected plot information and the signal magnitude P2 from the previous pulse compression result based on the signal magnitude P2 Calculate the RMS magnitude (P1) for each pulse among the signal magnitudes in the corresponding distance cell (Rin), and calculate the signal processing gain (DFB_GAIN) determined by the number of pulses and the shape of the Doppler window (Wi) used,
When the power difference (P2-P1) for each signal processing step is calculated within a preset error range based on the signal processing gain (DFB_GAIN), it is considered to be reflected by the actual target, and the power difference for each signal processing step ( If P2-P1) is calculated to be outside the preset error range based on the signal processing gain (DFB_GAIN), it is considered to be reflected by the external interference signal, and the frequency is avoided by counting the frequency of occurrence of the interference signal plot at the corresponding frequency Signal processing gain-based interference signal plot removal method, characterized in that used for. delete delete delete delete 8. The method of claim 7,
The detected plot information includes at least one of a Doppler value, a detected distance/Doppler cell index, a signal-to-noise ratio (SNR), and a monopulse angle (azimuth/elevation). How to remove. 8. The method of claim 7,
The signal processing gain-based interference signal plot removal method, characterized in that the magnitude of the preset signal processing gain is within a preset error range.

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