KR20220168728A - Apparatus and method for generating a range-doppler map using data correlation in a rader system - Google Patents

Abstract

According to the present disclosure, in a radar system, a device which generates a range-Doppler map using distance-aligned signal data generated based on a radar reflection signal including a plurality of pulses comprises: a phase compensation determiner which determines phase compensation values corresponding to the plurality of pulses based on entropy with respect to complex data in the distance-aligned signal data; a map pattern determiner which determines a pattern of a first range-Doppler map based on the distance-aligned signal data and a pattern of a second range-Doppler map based on the distance-aligned signal data and the phase compensation values; a movement amount determiner which determines a cell movement amount in relation to a distance in a pulse data unit based on a correlation between pieces of complex data in the pattern of the first range-Doppler map and the pattern of the second range-Doppler map; and a map generator which generates a range-Doppler map based on the pattern of the second range-Doppler map and the cell movement amount.

Description

APPARATUS AND METHOD FOR GENERATING A RANGE-DOPPLER MAP USING DATA CORRELATION IN A RADER SYSTEM

The present disclosure generally relates to a radar system for generating a range-Doppler map using a radar signal reflected from a target, and more particularly to a range-aligned signal generated based on a radar signal comprising a plurality of pulses. An apparatus and method for generating an unambiguous distance-Doppler map from data using data correlation.

Radar refers to a device that transmits radio frequency signals to a target and receives reflected waves reflected from the target to obtain information about the distance between the radar and the target or the shape of the target. Accordingly, radar is widely used as a military device for tracking targets such as enemy missiles or aircraft.

In general, a radar detects and tracks a target using a radio frequency (RF) signal-based ultra-high frequency radar sensor in a microwave band, and obtains information about the target. According to one example, a radar system obtains information about a target from a range-Doppler map by generating a range-Doppler map (RD map). A radar transmits a radar signal including a plurality of linearly modulated pulses and receives a signal reflected from a target to obtain distance information from the plurality of pulses of the received signal to the target. Thereafter, the radar generates a 2D distance-Doppler map by collecting pulse signals having identically aligned distance information and applying a Fourier transform in the Doppler direction. Since the Doppler frequency can be converted into speed, the radar can easily detect and track the target by obtaining the distance and speed of the target respectively from the 2D distance-Doppler map, and the shape according to the 2D distance-Doppler map. Through this, it is possible to check the scattering pattern of the target.

In order to generate a range-Doppler map, a signal processing device of a radar compensates for a moving distance of a target that occurs while a plurality of pulses are received and aligns a position using a range bin. That is, a clear distance-Doppler map can be obtained only when Doppler processing is performed after compensating for phase shift due to velocity for each pulse and target.

However, since it is practically impossible to accurately determine the distance and speed of the target, an error may occur between the actual speed of the target and the speed used for phase compensation. In particular, in the case of an aerial target with a relatively high speed, there is a higher probability that an error between the actual speed and the speed used for phase compensation will occur. In order to solve this problem, the distance-Doppler map generation apparatus compensates for the phase error between each pulse through entropy minimization to generate a relatively clear distance-Doppler map. However, when using the entropy minimization method, since not only the phase compensation value having the minimum entropy value but also other phase compensation values obtained by adding a linear phase to the phase value satisfy the minimum entropy value, the phase compensation value satisfying the minimum entropy value There are countless of these. Accordingly, it is difficult for the conventional range-Doppler map generation device to accurately predict a speed proportional to a Doppler frequency, and overall radar detection and tracking performance for a target is degraded.

Based on the above discussion, the present disclosure provides an apparatus and method for generating a range-Doppler map using range-aligned signal data generated from a radar signal including a plurality of pulses.

In addition, the present disclosure provides an apparatus and method for clearly generating a distance-Doppler map by determining a phase value necessary for motion compensation caused by a distance and speed of a target through entropy minimization.

In addition, the present disclosure provides an apparatus and method for explicitly generating a distance-Doppler map using data correlation with respect to a blurred distance-Doppler map and a phase-compensated distance-Doppler map.

According to various embodiments of the present disclosure, in a radar system, an apparatus for generating a range-Doppler map using range-aligned signal data generated based on a radar reflection signal including a plurality of pulses includes: A phase compensation determiner for determining phase compensation values corresponding to the plurality of pulses based on entropy of complex data in the distance-aligned signal data, a pattern of a first distance-Doppler map based on the distance-aligned signal data (pattern) and a map pattern determiner for determining a pattern of a second distance-Doppler map based on the distance-aligned signal data and the phase compensation values, a pattern of the first distance-Doppler map and the second distance-Doppler map A movement amount determiner for determining a cell movement amount for a distance of a pulse data unit based on a correlation between complex data in the pattern of, and a distance based on the pattern of the second distance-Doppler map and the cell movement amount -Can include a map generator that creates a Doppler map.

According to another embodiment, the phase compensation determiner initializes a first phase compensation value, determines entropy of the distance-aligned signal data based on the complex data and the first phase compensation value, and determines the entropy of the distance-aligned signal data. Determines a second phase compensation value at which is the minimum, identifies whether a difference between the second phase compensation value and the first phase compensation value is smaller than a preset threshold value, and determines whether the second phase compensation value and the first phase compensation value are equal to each other. When the difference between the first phase compensation values is smaller than the threshold value, a second phase compensation value may be output.

According to another embodiment, the phase compensation determiner sorts the distance based on the complex data and the second phase compensation value when the difference between the second phase compensation value and the first phase compensation value is greater than or equal to a threshold value. Entropy of the signal data may be determined, and a third phase compensation value having the minimum entropy may be determined.

According to another embodiment, the entropy may include Shannon entropy.

According to another embodiment, the pattern of the first distance-Doppler map indicates a pattern of a blurring distance-Doppler map in which a Fourier transform is applied to the distance-aligned signal data, and the pattern of the second distance-Doppler map is applied. The pattern of the map may indicate a pattern of a phase compensation distance-Doppler map in which a Fourier transform is applied to the distance-aligned signal data to which the phase compensation value is applied.

According to another embodiment, the movement amount determiner may include at least one first complex data corresponding to the position of the target in the pattern of the first distance-Doppler map and the position of the target in the pattern of the second distance-Doppler map. It is possible to determine a circular correlation between the second complex data corresponding to , and to determine a cell movement amount of a pulse data unit based on the size of the circular correlation.

According to another embodiment, the movement amount determiner may determine, as the cell movement amount, a distance at which the magnitude of the circular correlation is maximized.

According to an embodiment of the present disclosure, in a radar system, an apparatus for generating a range-Doppler map using range-aligned signal data generated based on a radar reflection signal including a plurality of pulses The operating method includes determining phase compensation values corresponding to the plurality of pulses based on entropy of complex data in the distance-aligned signal data, and a first distance-Doppler map based on the distance-aligned signal data. Determining a pattern of a second distance-Doppler map based on a pattern and the distance-aligned signal data and the phase compensation values; Determining a cell movement amount with respect to a distance of a pulse data unit based on a correlation between complex data in a pattern, and a distance-Doppler based on the pattern of the second distance-Doppler map and the cell movement amount It may include generating a map.

According to another embodiment, the pattern of the first distance-Doppler map indicates a pattern of a blurring distance-Doppler map in which a Fourier transform is applied to the distance-aligned signal data, and the pattern of the second distance-Doppler map is applied. The pattern of the map may indicate a pattern of a phase compensation distance-Doppler map in which a Fourier transform is applied to the distance-aligned signal data to which the phase compensation value is applied.

According to another embodiment, the determining of the cell movement amount may include determining the first complex data corresponding to the position of the target in the pattern of the first range-Doppler map and the pattern of the second range-Doppler map. The method may include determining a circular correlation between the second complex data corresponding to the position of the target, and determining a cell movement amount of a pulse data unit based on the size of the circular correlation.

According to another embodiment, the determining of the cell movement amount may include determining, as the cell movement amount, a distance at which the magnitude of the circular correlation is maximized.

Each of the various aspects and features of the invention are defined in the appended claims. Combinations of features of the dependent claims may be combined with features of the independent claims as appropriate, not just those explicitly set forth in the claims.

In addition, one or more selected features of any one embodiment described in this disclosure may be combined with one or more selected features of any other embodiment described in this disclosure, and alternatives of such features The combination of the present disclosure at least partially alleviates one or more technical problems discussed in the present disclosure, or at least partially alleviates the technical problems discernable by a person skilled in the art from the present disclosure, and further features of the embodiments ( A particular combination or permutation so formed of embodiment features is possible, provided that it is not understood by a person skilled in the art to be incompatible.

In any described example implementation, two or more physically separate components may alternatively be integrated into a single component, where such integration is possible, and a single component so formed If the same function is performed by , the integration is possible. Conversely, a single component in any embodiment described in this disclosure may alternatively be implemented as two or more separate components that achieve the same function, where appropriate.

It is an object of certain embodiments of the present invention to address, mitigate, or eliminate, at least in part, at least one of the problems and/or disadvantages associated with the prior art. Certain embodiments aim to provide at least one of the advantages described below.

An apparatus and method according to various embodiments of the present disclosure enable a clear range-Doppler map to be generated by correcting an error using correlation in a radar system.

Apparatus and method according to various embodiments of the present disclosure can increase the accuracy of the target's velocity estimation value by determining a clear range-Doppler map pattern for an aerial target for which it is difficult to accurately know the target's distance and velocity. .

An apparatus and method according to various embodiments of the present disclosure enable a radar system to increase detection and tracking performance of a target.

Effects obtainable in the present disclosure are not limited to the effects mentioned above, and other effects not mentioned may be clearly understood by those skilled in the art from the description below. will be.

1 illustrates a radar system according to various embodiments of the present disclosure.
2 illustrates a schematic diagram of a method for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure.
3 shows a schematic diagram of a method for generating a range-Doppler map by compensating for a phase through an entropy minimization method in a conventional radar system.
4 illustrates a configuration of a signal processor in a radar system according to various embodiments of the present disclosure.
5 is a block diagram of an operating method of an apparatus for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure.
6 illustrates a schematic diagram of a method of generating a distance-Doppler map in which an error is compensated for using correlation in a radar system according to various embodiments of the present disclosure.
7 is a flowchart illustrating an operating method of an apparatus for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure.
8 is a flowchart illustrating a method for determining a phase compensation value in a radar system according to various embodiments of the present disclosure.
9 shows an example of target modeling and a range-Doppler map for a target in a conventional radar system.
10 illustrates an example of a range-Doppler map generated by an apparatus for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure.
11 illustrates an example of a range-Doppler map generated by an apparatus for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure.

Terms used in the present disclosure are only used to describe a specific embodiment, and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art described in this disclosure. Among the terms used in the present disclosure, terms defined in general dictionaries may be interpreted as having the same or similar meanings as those in the context of the related art, and unless explicitly defined in the present disclosure, ideal or excessively formal meanings. not be interpreted as In some cases, even terms defined in the present disclosure cannot be interpreted to exclude embodiments of the present disclosure.

In various embodiments of the present disclosure described below, a hardware access method is described as an example. However, since various embodiments of the present disclosure include technology using both hardware and software, various embodiments of the present disclosure do not exclude software-based access methods.

Hereinafter, the present disclosure relates to an apparatus and method for generating a range-Doppler map in a radar system. Specifically, the present disclosure describes a technique for generating an unambiguous range-Doppler map using correlation with respect to range-aligned signal data generated based on a radar signal including a plurality of pulses.

Hereinafter, various embodiments will be described in detail so that those skilled in the art can easily implement the present disclosure with reference to the accompanying drawings. However, since the technical spirit of the present disclosure may be implemented in various forms, it is not limited to the embodiments described herein. In describing the embodiments disclosed in this specification, if it is determined that a detailed description of a related known technology may obscure the gist of the technical idea of the present disclosure, a detailed description of the known technology will be omitted. The same or similar components are assigned the same reference numerals, and duplicate descriptions thereof will be omitted.

In this specification, when an element is described as being “connected” to another element, this includes not only the case of being “directly connected” but also the case of being “indirectly connected” with another element intervening therebetween. When an element "includes" another element, this means that it may further include another element without excluding another element in addition to the other element unless otherwise stated.

Some embodiments may be described as functional block structures and various processing steps. Some or all of these functional blocks may be implemented with any number of hardware and/or software components that perform a particular function. For example, functional blocks of the present disclosure may be implemented by one or more microprocessors or circuit configurations for a predetermined function. The functional blocks of this disclosure may be implemented in a variety of programming or scripting languages. The functional blocks of this disclosure may be implemented as an algorithm running on one or more processors. The functions performed by the function blocks of the present disclosure may be performed by a plurality of function blocks, or the functions performed by the plurality of function blocks in the present disclosure may be performed by one function block. In addition, the present disclosure may employ prior art for electronic environment setting, signal processing, and/or data processing.

In addition, in the present disclosure, the expression of more than or less than is used to determine whether a specific condition is satisfied or fulfilled, but this is only a description to express an example and excludes more or less description. It's not about doing it. Conditions described as 'above' may be replaced with 'exceeds', conditions described as 'below' may be replaced with 'below', and conditions described as 'above and below' may be replaced with 'above and below'.

'...' is used below. wealth', '… A term such as 'group' refers to a unit that processes at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software. The distance-Doppler map generator may include a communication unit, a storage unit, and a control unit. The storage unit, the communication unit, and the control unit may be functionally coupled to at least one processor to operate.

1 illustrates a radar system 100 according to various embodiments of the present disclosure. The radar system 100 may include a radar sensor 110 and a target 160 . According to the radar system 100, the radar sensor 110 may extract target information using a received signal in which an ultra-high frequency signal transmitted from the radar is scattered from the target. 1 shows a case in which a radar sensor 110 and a target 160 are respectively provided in a radar system, however, the number of radar sensors and targets may be plural depending on circumstances.

According to the radar system 100, the radar sensor 110 performs a function for detecting or tracking a target. The radar sensor 110 transmits a radio frequency (RF) signal to the target 160 and receives a signal reflected from the target. The radar sensor 110 may obtain information about the distance between the radar sensor 110 and the target 160 or the shape of the target by using the reflected received signal.

According to an embodiment of the present disclosure, the radar sensor 110 may perform a conversion function between a base band signal and a bit stream in order to transmit a radar signal. For example, when transmitting data, the radar sensor 110 may generate complex symbols by encoding and modulating a transmission bit stream. The radar sensor 110 includes a frequency synthesizer 111 for synthesizing frequencies to modulate a phase, a transmitter 113 for up-converting a baseband signal to a radio frequency (RF) band signal, and at least one antenna element. It may include a transmission antenna 115 that transmits a radar signal using an antenna array. Through this, the radar sensor 110 may transmit a radar signal to the target through the transmit antenna 115 .

According to an embodiment of the present disclosure, the radar sensor 110 may acquire information about the target by receiving an RF signal reflected from the target. The radar sensor 110 includes a receiving antenna 117 for receiving an RF signal reflected from a target using at least one antenna array composed of antenna elements, a receiver 119 for down-converting an RF band signal to a baseband signal, A signal processor 121 for processing the down-converted signal may be included. Through this, the radar sensor 110 may demodulate and decode the baseband signal to restore the received bit stream.

2 illustrates a schematic diagram 200 of a method for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure.

Referring to FIG. 2 , the signal processor 121 obtains a received signal 201 that is a radar signal reflected from a target. The radar sensor 110 may transmit a radar signal including a plurality of linearly modulated pulses to a target and receive a signal reflected from the target. Accordingly, the radar signal may include M pulses, and the signal processor 121 may receive the received signal 201 including M pulses.

Thereafter, the signal processor 121 may obtain signal data 203 by processing the received signal. The signal processor 121 may generate signal data 203 related to distance information by applying pulse compression or stretch processing to the received signal 201 . Here, the signal data may be expressed as a signal matrix, and the values of the signal data may include complex values. Also, the size of the signal data may be determined based on the number M of pulses included in the radar signal and the number N of total range bins. According to an embodiment of the present disclosure, signal data may be determined as an MxN matrix.

Thereafter, the signal processor 121 may obtain distance-aligned signal data 205 by performing distance alignment to match the centers of the signal data in distance bin units in the signal data 203 . The size of the complex data including the information about the target is greater than the size of the complex data not including the information about the target. Accordingly, the signal processor 121 may generate distance-aligned signal data by comparing the size of complex data included in the signal data and matching the distance information on the target. Accordingly, the distance-aligned signal data may be determined to have a size of M x N.

Thereafter, the signal processor 121 may generate a distance-Doppler map 207 by performing a Fourier transform on the distance-aligned signal data 205 . According to an embodiment of the present disclosure, the signal processor 121 may apply a Doppler direction Fourier transform to the distance-aligned signal data 205 . According to an embodiment of the present disclosure, the signal processor 121 applies Fourier transform in the Doppler direction after compensating for the error using phase compensation values according to the speed error corresponding to each pulse in the distance-aligned signal data. can do. A user of the radar sensor may obtain distance and speed information about the target using the generated range-Doppler map.

FIG. 3 shows a schematic diagram 300 of a method of generating a range-Doppler map by compensating a phase through an entropy minimization method in a conventional radar system.

Referring to FIG. 3 , the signal processor 121 may generate distance aligned signal data 301 based on a radar signal reflected from a target. The distance-aligned signal data 301 may be generated according to the same method as the method in which the signal processor 121 generates the distance-aligned signal data 205 in FIG. 2 . Accordingly, distance aligned signal data may be expressed as a signal matrix, and values of the signal data may include complex values. Also, the size of the signal data may be determined based on the number M of pulses included in the radar signal and the number N of total distance bins. According to an embodiment, signal data may be determined as an MxN matrix.

The signal processor 121 determines a phase compensation value φ(303) for compensating a phase error related to speed. The signal processor 121 may determine phase compensation values corresponding to each of a plurality of pulses in the distance aligned signal data 301 . According to an embodiment, the signal processor 121 may determine the phase compensation value φ 303 based on the magnitude of complex data corresponding to the intensity of the signal. Here, the phase compensation value φ 303 may include M complex data corresponding to each of the M pulses.

Then, the signal processor 121 may generate phase compensated signal data 305 based on the distance alignment signal data 301 and the phase compensation value φ 303 . Signal processor 121 applies the phase compensation values to distance aligned signal data 301 to generate phase compensated signal data 305 . That is, the signal processor 121 may determine M phase compensation values having a minimum entropy value and apply the phase compensation values to the distance-aligned signal data signal to compensate for the phase. According to an embodiment, the signal processor 121 may compensate for the phase by applying the phase compensation value φ 303 to the distance-aligned signal data 301 through element-by-element multiplication.

Thereafter, the signal processor 121 may generate a phase-compensated distance-Doppler map 307 by signal processing the phase-compensated signal data 305 . According to an embodiment, the signal processor 121 may generate a phase-compensated distance-Doppler map 307 by applying a Fourier transform in a Doppler direction to the phase-compensated signal data 305 . A user of the radar sensor may obtain distance and speed information about the target using the generated range-Doppler map.

Referring to FIG. 3 , the signal processor 121 may generate a range-Doppler map with high clarity by compensating signal data for phases related to the distance and speed of the target. Here, the signal processor 121 may use an entropy minimization method for determining a phase value in which the absolute value of the magnitude of the signal satisfies the minimum entropy value in order to determine the phase compensation value φ(303).

When a phase compensation value is determined according to a general entropy minimization method, a phase value obtained by adding a linear phase to the determined phase compensation value also satisfies the minimum entropy value. That is, there may be infinitely many phase compensation values that satisfy entropy minimization. The difference in linear phase has the same image quality, but causes a circular shift in the vertical (cross range) direction, and since the velocity proportional to the clear Doppler frequency cannot be predicted, radar detects and tracks the target. Performance may deteriorate.

4 illustrates a configuration 400 of a signal processor 121 in a radar system according to various embodiments of the present disclosure.

Referring to FIG. 4 , when the radar sensor 110 receives a radar signal reflected from a target, the signal processor 121 processes the received signal to obtain information about the target. That is, the signal processor 121 may process the radar signal to generate signal data and obtain target information from the signal data. In this case, the signal data may be expressed as a signal matrix. According to an embodiment of the present disclosure, the signal processor 121 may include a signal data generator 411 and a distance-Doppler map generator 461 .

As shown in FIG. 4, a case in which the signal processor 121 includes the signal data generator 411 and the distance-Doppler map generator 461 is exemplified, but the signal data generator 411 and the distance - The Doppler map generating device 461 is configured as a separate device distinct from the signal processor 121, and may operate in connection with the signal processor 121.

The signal data generating device 411 performs a function of generating signal data aligned with a distance from a radar signal. According to an embodiment of the present disclosure, the signal data generating apparatus 411 generates signal data by applying a pulse compression method or stretch processing to a radar signal including a plurality of pulses, and generates a center of the signal data in units of distance bins. You can perform distance sorting to match . In this case, the signal data may be expressed as a signal matrix, and the size of the signal matrix may be determined based on the number of pulses and the number of distance bins included in the radar signal. The signal data generator 411 outputs the generated distance aligned signal data to the distance-Doppler map generator 461 .

The distance-Doppler map generator 461 performs a function of generating a distance-Doppler map using distance-aligned signal data. The distance-Doppler map generator 461 may generate a distance-Doppler map by Fourier transforming distance-aligned signal data generated by collecting a plurality of pulse signals in a Doppler direction. In this case, the distance-Doppler map generator 461 may generate a distance-Doppler map using an entropy minimization technique in the distance-aligned signal data. According to an embodiment of the present disclosure, the distance-Doppler map generator 461 includes a phase compensation determiner 471, a map pattern determiner 473, a movement amount determiner 475, and a map generator 477.

The phase compensation determiner 471 determines phase compensation values corresponding to each of a plurality of pulses based on distance aligned signal data. According to an embodiment of the present disclosure, the phase compensation determiner 471 determines a phase compensation value according to a speed error using complex data for each pulse in all distance bins. Accordingly, the phase compensation determiner 471 may determine as many phase compensation values as the number of pulses.

The map pattern determiner 473 determines a distance-Doppler map pattern using distance-aligned signal data and phase compensation values. According to an embodiment of the present disclosure, the map pattern determiner 473 may determine a first distance-Doppler map pattern by applying a Fourier transform to distance-aligned signal data. Here, the first distance-Doppler map indicates a blurred map. In addition, the map pattern determiner 473 may determine a pattern of the second distance-Doppler map by applying a Fourier transform to signal data distance-aligned with the phase compensation values. The map pattern determiner 473 may determine a pattern of the second distance-Doppler map by multiplying and applying the determined phase compensation values to distance-aligned signal data generated by collecting a plurality of pulse signals. Here, the second distance-Doppler map indicates an auto-focused map.

The movement amount determiner 475 determines a cell movement amount based on a correlation between complex data in the first distance-Doppler map pattern and the second distance-Doppler map pattern. According to an embodiment of the present disclosure, the movement amount determiner 475 determines a cell movement amount for which a maximum value of a vertical circular correlation between images in two patterns of the distance-Doppler map is calculated. Here, the cell movement amount may indicate a distance in pulse data units. The movement amount determiner 475 determines a vertical distance direction correlation between the first distance-Doppler map pattern and the second distance-Doppler map pattern received from the map pattern determiner 473. The movement amount determiner 475 uses the determined correlation as a matching score and determines a movement amount corresponding to a value with the largest matching score as a cell movement amount.

The map generator 477 performs a function of generating a distance-Doppler map by applying a cell movement amount to a pattern of the second distance-Doppler map. According to an embodiment of the present disclosure, the map generator 477 generates a final distance-Doppler map by applying the cell movement amount to a pattern of the second distance-Doppler map.

Referring to FIG. 4 , the distance-Doppler map generator 461 determines a pattern of a second distance-Doppler map in which a phase error related to speed is compensated. That is, the pattern of the second distance-Doppler map may have sharp image quality with focus adjusted through the phase compensation values, but include an error related to sharpness. Here, the distance-Doppler map generator 461 according to the present disclosure determines and reflects the cell movement amount from the correlation between the complex data in the second distance-Doppler map pattern and the blurred first distance-Doppler map pattern. By doing so, it is possible to generate a final distance-Doppler map with sharpness and reduced error related to sharpness.

5 is a block diagram 500 of an operating method of a range-Doppler map generator 461 in a radar system according to various embodiments of the present disclosure. 5 illustrates an operating method of the distance-Doppler map generator 461 .

Referring to FIG. 5 , the signal data generating device 411 may generate distance-aligned signal data and output the same to the distance-Doppler map generating device 461 . Here, the distance-aligned signal data may include M×N matrix data. In this case, M may indicate the number of pulses, and N may indicate the number of total distance bins. Also, the value of each signal data may be expressed as complex values. The distance-aligned signal data is input to the phase compensation determiner 471 and the map pattern determiner 473.

The phase compensation determiner 471 determines phase compensation values corresponding to a plurality of pulses in units of all distance bins in the distance-aligned signal data. The phase compensation determiner 471 may determine a phase compensation value for each of a plurality of pulses through entropy minimization using complex data included in distance aligned signal data. According to an embodiment of the present disclosure, entropy used to determine phase compensation may include at least one of tsallis entropy and shannon entropy. Hereinafter, the phase compensation determiner 471 determines the phase compensation value having the minimum entropy value using Shannon entropy, but may determine the phase compensation value using other entropy values.

Distance-aligned signal data including M pulses may be expressed as matrix data. Here, assuming that the matrix data is f(x,n), the complex image signal matrix z(m,n) obtained by applying the Fourier transform in the Doppler direction to the matrix data f(x,n) can be determined as shown in Equation 1. .

Referring to Equation 1, z(m,n) is complex image signal matrix data, f(x,n) is signal data including M pulses, M is the number of pulses, and φ is a phase compensation value. instruct

If Shannon entropy is calculated with respect to the magnitude of the absolute value of the complex image signal matrix data, the Shannon entropy value can be determined as shown in Equation 2.

Referring to <Equation 2>, E _shannon is the Shannon entropy value, z (m, n) is the complex image signal matrix for distance-aligned signal data, M is the number of pulses of the radar reflection signal, and N is the distance bin indicate the size

The phase compensation determiner 471 may determine M phase compensation values that minimize the Shannon entropy value determined through Equation 2. Then, the phase compensation determiner 471 outputs the determined phase compensation value to the map pattern determiner 473.

Map pattern determiner 473 generates a pattern of the distance-Doppler map. According to an embodiment of the present disclosure, the map pattern determiner 473 may generate a first distance-Doppler map pattern based on distance-aligned signal data. Here, the first distance-Doppler map includes accurate information about the position of the target, but indicates a blurred map because the phase is not compensated for the speed. Also, the map pattern determiner 473 may generate a second distance-Doppler map pattern based on the phase compensation value and distance-aligned signal data. Here, the second distance-Doppler map indicates an auto-focused map to which a phase compensation value is applied. The map pattern determiner 473 outputs the first distance-Doppler map pattern to the movement amount determiner 475 and outputs the second distance-Doppler map pattern to the movement amount determiner 475 and the map generator 477.

The movement amount determiner 475 determines a cell movement amount based on a correlation between a pattern of the first distance-Doppler map and complex data in the second distance-Doppler map. According to an embodiment of the present disclosure, the movement amount determiner 475 identifies a range bin where a target is located based on the size of complex data in patterns of a range-Doppler map. Then, the movement amount determiner 475 determines circular correlation values in a vertical direction between images in the first distance-Doppler map pattern and the second distance-Doppler map pattern with respect to the identified distance bin. That is, the movement amount determiner 475 uses circular correlation values as matching scores, and determines a movement amount that produces the largest matching score as a cell movement amount.

According to another embodiment of the present disclosure, in order to increase the accuracy of the matching score, the movement amount determiner 475 does not use the complex data itself regarding the pattern of the first distance-Doppler map, but slides in the vertical direction. complex data can be used. The movement amount determiner 475 may determine a correlation between the complex data of the first distance-Doppler map pattern slid by the preset number of cells in the vertical direction and the complex data of the second distance-Doppler map pattern. Thereafter, the movement amount determiner 475 may determine a cell movement amount based on the determined size of the correlation. The movement amount determiner 475 transfers the determined cell movement amount to the map generator 477.

The map generator 477 performs a function of generating a final distance-Doppler map using the pattern of the second distance-Doppler map and the cell movement amount. The map generator 477 may generate a distance-Doppler map in which position errors are compensated for by applying a cell movement amount to the auto-focused second distance-Doppler map pattern.

FIG. 6 illustrates a schematic diagram 600 of a method of generating a distance-Doppler map in which an error is compensated for using correlation in a radar system according to various embodiments of the present disclosure. 6 illustrates an operating method of the distance-Doppler map generator 461 .

The distance-Doppler map generator 461 may obtain a first distance-Doppler map pattern 601 and a second distance-Doppler map pattern 603 by using the map pattern determiner 473 . As shown in FIG. 6, the pattern 601 of the first range-Doppler map indicates the position of the target using a plurality of vertical distance bins and contains accurate information about the position of the target, but phase with respect to velocity. This is not compensated for, resulting in blurring. In addition, the pattern 603 of the second distance-Doppler map transmits information about the position of the target with clear image quality by applying the phase compensation value determined through entropy minimization to signal data, but an error exists.

Correspondingly, the distance-Doppler map generating device 461 uses the correlation between the first distance-Doppler map pattern 601 and the second distance-Doppler map pattern 603 to determine the final distance for which the error is compensated. - A Doppler map 605 can be generated. According to an embodiment of the present disclosure, the range-Doppler map generating device 461 is configured to obtain a range bin for a location of a target from a first range-Doppler map pattern 601 and a second range-Doppler map pattern 603. Identifies the location of the unit. Thereafter, the range-Doppler map generating device 461 performs a circular correlation in a vertical direction between complex data of a pattern of a first range-Doppler map with respect to complex data about a position of a target in a pattern of a second range-Doppler map. determine the values. The distance-Doppler map generator 461 determines the determined circular correlation values as matching scores, and determines a movement amount that produces the largest matching score as a cell movement amount. The range-Doppler map generating device 461 may generate a final range-Doppler map 605 similar to an actual target by applying the determined cell movement amount to a pattern of the auto-focused second range-Doppler map.

Referring to the first distance-Doppler map pattern 601, first complex data arranged in 4 rows and 3 columns and second complex data arranged in 3 rows and 5 columns have the largest sizes. Accordingly, referring to the first distance-Doppler map, it is identified that the target signal is included at the position of 4th row and 3rd column and the position of 3rd row and 5th column. However, since the pattern 601 of the first distance-Doppler map does not compensate for the phase, blurring may occur in a direction perpendicular to the first complex data and the second complex data, which is determined to be large.

Referring to the pattern 603 of the second distance-Doppler map, the sizes of the third complex data disposed in the second row and third column and the fourth complex data disposed in the first row and fifth column are the largest. That is, referring to the second distance-Doppler map, it is identified that the target signal is included at the location of the second row and column 3 and the location of the first row and column 5.

The distance-Doppler map generator 461 determines a circular correlation between the third and fourth complex data of the second distance-Doppler map pattern and the complex data in the first distance-Doppler map pattern. Accordingly, 2, which is the movement amount having the largest circular correlation, is determined as the cell movement amount, and the distance-Doppler map generator 461 applies the determined cell movement amount to the pattern 603 of the second distance-Doppler map, A final distance-Doppler map 605 may be generated.

7 is a flowchart 700 of an operating method of an apparatus 461 for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure.

Referring to FIG. 7 , in step 701, the distance-Doppler map generator 461 determines phase compensation values corresponding to a plurality of pulses based on entropy of complex data in distance-aligned signal data. According to an embodiment of the present disclosure, the distance-Doppler map generator 461 may determine phase compensation values that minimize an entropy value of complex data in distance-aligned signal data. Here, the phase compensation values may correspond to a plurality of pulses of the radar signal. According to an embodiment of the present disclosure, entropy used to determine phase compensation values may include at least one of Shannon entropy and Tsalis entropy.

In step 703, the distance-Doppler map generator 461 generates a first distance-Doppler map pattern based on the distance-aligned signal data and a second distance based on the distance-aligned signal data and phase compensation values. -Determine the pattern of the Doppler map. The distance-Doppler map generator 461 may generate a first distance-Doppler map pattern by applying a Fourier transform to the distance-aligned signal data. Also, the distance-Doppler map generator 461 may generate a second distance-Doppler map pattern by applying a Fourier transform after multiplying the distance-aligned signal data by element-by-element phase compensation values.

In step 705, the distance-Doppler map generating device 461 determines the distance of the pulse data unit based on the correlation between the complex data in the first distance-Doppler map pattern and the second distance-Doppler map pattern. Determine the amount of cell movement relative to The range-Doppler map generator 461 identifies a range bin where a target is located based on the size of complex data in patterns of the range-Doppler map. Thereafter, the distance-Doppler map generator 461 calculates circular correlation values in the vertical direction between images in the first distance-Doppler map pattern and the second distance-Doppler map pattern with respect to the identified distance bin. and a movement amount corresponding to a value that maximizes the circular correlation may be determined as the cell movement amount.

According to an embodiment of the present disclosure, the range-Doppler map generating device 461 includes at least one first complex data corresponding to the location of the target in the first range-Doppler map pattern and the second range-Doppler map pattern. A circular correlation between the second complex data corresponding to the position of the target may be determined in , and a cell movement amount of a pulse data unit may be determined based on the size of the circular correlation. Here, the distance-Doppler map generator 461 may determine, as the cell movement amount, a distance at which the size of the circular correlation is maximized.

In step 707, the distance-Doppler map generating device 461 generates a distance-Doppler map based on the pattern of the second distance-Doppler map and the amount of cell movement. According to an embodiment of the present disclosure, the distance-Doppler map generating device 461 may generate a final distance-Doppler map by applying a cell movement amount to a pattern of the second distance-Doppler map.

8 shows a flowchart 800 of a method for determining a phase compensation value in a radar system according to various embodiments of the present disclosure. 8 illustrates an operating method of the distance-Doppler map generator 461 .

Referring to FIG. 8 , in step 801, the distance-Doppler map generator 361 initializes a phase compensation value. The distance-Doppler map generator 361 initializes M phase compensation values to determine phase compensation values corresponding to a plurality of pulses. According to an embodiment of the present disclosure, phase compensation values may be determined as randomly generated values based on a random number generator.

In step 803, the distance-Doppler map generator 361 determines the entropy of the distance-aligned signal data based on the complex data and the phase compensation value. According to an embodiment of the present disclosure, the distance-Doppler map generator 361 may calculate an entropy value using a phase compensation value and complex data of distance-aligned signal data. According to an embodiment of the present disclosure, entropy may include Shannon entropy.

In step 805, the distance-Doppler map generator 361 determines a second phase compensation value that minimizes entropy. According to an embodiment of the present disclosure, the distance-Doppler map generating device 361 may determine M phase compensation values that minimize entropy values. Accordingly, the distance-Doppler map generator 361 may update phase compensation values.

In step 807, the distance-Doppler map generator 361 identifies whether a difference between the current phase compensation value and the previous phase compensation value is smaller than a preset threshold value. The distance-Doppler map generator 361 may compare a difference between a current phase compensation value and a previous phase compensation value with a threshold value with respect to M phase compensation values. According to an embodiment of the present disclosure, the distance-Doppler map generator 361 determines a phase compensation value having the largest phase compensation value difference as a reference phase compensation value, and determines a phase compensation value difference from the reference phase compensation value. It can be compared with a preset threshold. According to an embodiment of the present disclosure, the distance-Doppler map generator 361 may determine the current phase compensation value as the final phase compensation value when the difference between the phase compensation values is smaller than a preset threshold value. According to another embodiment of the present disclosure, the distance-Doppler map generator 361 proceeds to step 803 when the difference between the phase compensation values is greater than or equal to a preset threshold value, based on the complex data and the current phase compensation value. , it is possible to determine the entropy of the distance-aligned signal data.

9 shows an example 900 of target modeling and a range-Doppler map for a target in a conventional radar system.

FIG. 9 shows an example of a modeled target signal 901 when the radar sensor transmits a radar signal including a plurality of pulses to a target and receives a signal reflected from the target. As the radar sensor uses a radar signal including a plurality of pulses, the target may be modeled as a plurality of point scatterers corresponding to each of the plurality of pulses. Referring to the modeled target signal 901, the horizontal axis and the vertical axis indicate the distance.

The range-Doppler map generating device may generate a range-Doppler map based on the modeled target signal 901 . Referring to FIG. 9 , an accurate distance-Doppler map 903 when the phase is compensated based on the accurate speed and a first distance-Doppler map 905 when the phase compensation for the speed is not applied are shown. Also, in each of the distance-Doppler maps of FIG. 9, a horizontal axis indicates a horizontal distance bin of a linear scale, and a vertical axis indicates a vertical distance bin of a linear scale.

The accurate range-Doppler map 903 exemplifies a result of forming a range-Doppler map after performing phase compensation based on the center position of the target using the accurate speed of the target. Since the accurate range-Doppler map 903 is a result of generating the range-Doppler map based on the accurate speed of the target, an error regarding the focus of the image is small.

The first distance-Doppler map 905 exemplifies a case in which Fourier transform is applied in a state in which a phase compensation value for the speed of a target is not applied. Referring to the first distance-Doppler map 905, blurring occurs in the distance-Doppler map due to a speed error, and accordingly, a focus error of an image is large.

10 illustrates an example 1000 of a range-Doppler map generated by an apparatus for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure. 10 indicates a range-Doppler map corresponding to the target modeled in FIG. 9 . Also, in FIG. 10 , a horizontal axis indicates a log scale horizontal distance bin, and a vertical axis indicates a log scale vertical distance bin.

Referring to FIG. 10 , an accurate distance-Doppler map 1001 when phase is compensated based on an accurate speed, a second distance-Doppler map 1003 using an entropy minimization method, and an apparatus for generating a distance-Doppler map according to the present disclosure The final distance-Doppler map 1005 generated by .

The distance-Doppler map generating device 461 may generate the second distance-Doppler map 1003 using an entropy minimization method. The second distance-Doppler map 1003 may have auto-focused and clear image quality as a phase error related to speed is reflected. However, the second range-Doppler map 1003 has a large error in relation to the position of the target compared to the accurate range-Doppler map 1001.

The distance-Doppler map generating device 461 may generate the final distance-Doppler map 1005 by using the correlation of complex data in the first distance-Doppler map and the second distance-Doppler map 1003 . The distance-Doppler map generating device 461 sets correlation values between complex data as a matching score and compensates for a cell movement amount for which the matching score is maximized. Therefore, the final distance-Doppler map 1005 generated by the distance-Doppler map generator 461 according to the present disclosure is similar to the accurate distance-Doppler map 1001 in which phase compensation is determined using the actual velocity. That is, the final range-Doppler map 1005 has a small error in relation to the position of the target compared to the second range-Doppler map 1003.

11 illustrates an example 1100 of a range-Doppler map generated by an apparatus for generating a range-Doppler map in a radar system according to various embodiments of the present disclosure. 11 indicates a range-Doppler map corresponding to the target modeled in FIG. 9 . Also, in FIG. 11 , a horizontal axis indicates a horizontal distance bin of a linear scale, and a vertical axis indicates a vertical distance bin of a linear scale.

Referring to FIG. 11 , an accurate distance-Doppler map 1101 and a distance-Doppler map 1103 generated by the apparatus for generating a distance-Doppler map according to the present disclosure are shown when the phase is compensated based on the accurate speed. FIG. 11 shows that the unit of the horizontal axis and the vertical axis in FIG. 10 is changed from a dB scale to a linear scale. Therefore, as shown in FIG. 10 , the distance-Doppler map generator 461 according to the present disclosure can generate a distance-Doppler map with less error compared to the accurate distance-Doppler map 1101 for which phase compensation is determined using the actual speed. there is.

Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

Such programs (software modules, software) may include random access memory, non-volatile memory including flash memory, read only memory (ROM), and electrically erasable programmable ROM. (electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other It can be stored on optical storage devices, magnetic cassettes. Alternatively, it may be stored in a memory composed of a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

In addition, the program is provided through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a communication network consisting of a combination thereof. It can be stored on an attachable storage device that can be accessed. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. In addition, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in singular or plural numbers according to the specific embodiments presented. However, the singular or plural expressions are selected appropriately for the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components, and even components expressed in plural are composed of the singular number or singular. Even the expressed components may be composed of a plurality.

Meanwhile, in the detailed description of the present disclosure, specific embodiments have been described, but various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments and should not be defined by the scope of the claims described below as well as those equivalent to the scope of these claims.

Claims (12)

In a radar system, an apparatus for generating a range-Doppler map using range-aligned signal data generated based on a radar reflection signal including a plurality of pulses,
a phase compensation determiner determining phase compensation values corresponding to the plurality of pulses based on entropy of complex data in the distance-aligned signal data;
a map pattern determiner for determining a pattern of a first distance-Doppler map based on the distance-aligned signal data and a pattern of a second distance-Doppler map based on the distance-aligned signal data and the phase compensation values;
a movement amount determiner configured to determine a cell movement amount with respect to a distance of a unit of pulse data based on a correlation between complex data in the pattern of the first distance-Doppler map and the pattern of the second distance-Doppler map; and
and a map generator configured to generate a distance-Doppler map based on the pattern of the second distance-Doppler map and the cell movement amount.
The method of claim 1,
The phase compensation determiner,
Initialize a first phase compensation value;
determining entropy of the distance-aligned signal data based on the complex data and the first phase compensation value;
determining a second phase compensation value at which the entropy is minimized;
Identifying whether a difference between the second phase compensation value and the first phase compensation value is smaller than a preset threshold value;
and outputting a second phase compensation value when a difference between the second phase compensation value and the first phase compensation value is less than a threshold value.
The method of claim 2,
The phase compensation determiner,
When the difference between the second phase compensation value and the first phase compensation value is greater than or equal to a threshold value,
determining entropy of the distance-aligned signal data based on the complex data and the second phase compensation value;
A distance-Doppler map generator for determining a third phase compensation value at which the entropy is minimized.
The method of claim 2,
The entropy includes Shannon entropy,
The phase compensation determiner determines the Shannon entropy based on the following equation: a distance-Doppler map generator:

Here, E _shannon is the Shannon entropy value, z(m,n) is the complex image signal matrix for the distance-aligned signal data, M is the number of pulses of the radar reflection signal, and N is the size of the range bin.
The method of claim 1,
The pattern of the first distance-Doppler map indicates a pattern of a blurring distance-Doppler map in which a Fourier transform is applied to the distance-aligned signal data,
wherein the pattern of the second distance-Doppler map indicates a pattern of a phase-compensated distance-Doppler map in which a Fourier transform is applied to the distance-aligned signal data to which the phase compensation value is applied.
The method of claim 5,
The movement amount determiner,
Circular correlation between at least one piece of first complex data corresponding to a location of a target in the pattern of the first range-Doppler map and second complex data corresponding to the location of the target in the pattern of the second range-Doppler map. (circular correlation) is determined,
A distance-Doppler map generator for determining a cell movement amount of a pulse data unit based on the size of the circular correlation.
The method of claim 6,
The movement amount determiner,
A distance-Doppler map generator for determining, as a cell movement amount, a distance at which the magnitude of the circular correlation is maximized.
In a radar system, a method of operating a device for generating a range-Doppler map using range-aligned signal data generated based on a radar reflection signal including a plurality of pulses,
determining phase compensation values corresponding to the plurality of pulses based on entropy of complex data in the distance-aligned signal data;
determining a pattern of a first distance-Doppler map based on the distance-aligned signal data and a pattern of a second distance-Doppler map based on the distance-aligned signal data and the phase compensation values;
determining a cell movement amount with respect to a distance of a pulse data unit based on a correlation between complex data in the pattern of the first distance-Doppler map and the pattern of the second distance-Doppler map; and
and generating a distance-Doppler map based on the pattern of the second distance-Doppler map and the cell movement amount.
The method of claim 8,
The entropy includes Shannon entropy,
Determining the phase compensation values
A method of operating a distance-Doppler map generating device including determining Shannon entropy based on the following equation:

Here, E _shannon is the Shannon entropy value, z(m,n) is the complex image signal matrix for the distance-aligned signal data, M is the number of pulses of the radar reflection signal, and N is the size of the range bin.
The method of claim 8,
The pattern of the first distance-Doppler map indicates a pattern of a blurring distance-Doppler map in which a Fourier transform is applied to the distance-aligned signal data,
The pattern of the second distance-Doppler map indicates a pattern of a phase-compensated distance-Doppler map in which a Fourier transform is applied to the distance-aligned signal data to which the phase compensation value is applied.
The method of claim 10,
The step of determining the cell movement amount is
Circular correlation between at least one piece of first complex data corresponding to a location of a target in the pattern of the first range-Doppler map and second complex data corresponding to the location of the target in the pattern of the second range-Doppler map. determining a circular correlation; and
and determining a cell movement amount of a pulse data unit based on the size of the circular correlation.
The method of claim 11,
The step of determining the cell movement amount includes determining a distance that makes the magnitude of the circular correlation maximum as a cell movement amount.

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