KR101077837B1 - Method and Apparatus for Detecting Range and Velocity of Target by Using Radar and Computer Readable Recording Medium for Recording Program Therefor - Google Patents

Abstract

Embodiments of the present invention relate to a method and apparatus for detecting a distance velocity of a target using a radar and a computer-readable recording medium recording a program therefor.

An embodiment of the present invention detects an up bit frequency, a down bit frequency, and a Doppler frequency by using a radar transmission signal and a reception signal for a plurality of frequency-converted targets, and uses the up bit frequency, the down bit frequency, and the Doppler frequency. By selecting a pair of up-bit frequency and down-bit frequency, and using the up-bit frequency and down-bit frequency of the selected pair to provide a distance velocity detection method, characterized in that for calculating a distance and a speed for a plurality of targets.

According to an embodiment of the present invention, when detecting distances and velocities for a plurality of targets using a radar, correlated bit frequencies can be detected from a combination of all possible bit frequencies, thereby providing distance and Speed can be detected accurately and efficiently.

Radar, Target, Distance, Speed, Bit Frequency, Doppler, Pair, FMCW, Paring

Description

Method and apparatus for detecting distance velocity of target using radar and computer readable recording medium recording program therefor {Method and Apparatus for Detecting Range and Velocity of Target by Using Radar and Computer Readable Recording Medium for Recording Program Therefor}

Embodiments of the present invention relate to a method and apparatus for detecting a distance velocity of a target using a radar and a computer-readable recording medium recording a program therefor. More specifically, a method and apparatus for accurately and efficiently detecting distances and speeds of a plurality of real targets using a radar of a frequency modulated continuous wave (FMCW) method; A computer readable recording medium having recorded thereon a program therefor.

Today, the use of radar-based driver safety systems continues to expand. In particular, Adaptive Cruise Control (ACC) systems are already commercially available on the market using 24 GHz and 77 GHz radar. In such driver safety systems, even in the presence of multiple targets, the distance and speed of each target must be able to be measured simultaneously with high accuracy.

As a radar for measuring a distance and a speed of a target, a frequency modulated continuous wave (FMCW) radar is most widely used. However, when there are a plurality of targets, ambiguities appear in detecting distance and velocity from two viewpoints. The first aspect is a question of how accurately the relative speed and distance can be separated from the detected beat frequency, and the second aspect is a problem of detecting a plurality of targets by accurately combining the bit frequencies. to be. These problems generate ghost targets and missing targets in the process of detecting distance and speed with respect to the target. Here, the ghost target is an error that is not actually present but is detected and displayed in the signal processing, and the missing target is a target that cannot be detected due to an error in the signal processing even though it is actually present.

Several methods have been proposed to solve these problems, the most well known being the addition of Unmodulated Continuous Wave between Up Chirp and Down Chirp. to be. However, this method has a complicated problem of pairing the bit frequencies for a plurality of targets.

In order to solve the above-described problem, an embodiment of the present invention provides accurate and efficient pairing of correlated bit frequencies from all possible combinations of bit frequencies to accurately and efficiently detect distance and speed for a plurality of targets. There is a main purpose.

In order to achieve the above object, an embodiment of the present invention, a signal converter for frequency converting the transmission signal and the reception signal of the radar for a plurality of targets; A frequency detector for detecting up-bit frequency, down-bit frequency, and Doppler frequency using the frequency-converted transmit and receive signals; A correlation frequency candidate group detector for detecting a correlation frequency candidate group using the upbit frequency and the Doppler frequency; A comparator for comparing pairs of correlation frequency candidate groups and down bit frequencies to select a pair of up bit frequency and down bit frequency for a correlation frequency candidate having a value equal to the down bit frequency among the correlation frequency candidate groups; And a distance and speed calculator for calculating distances and speeds for a plurality of targets using the up bit frequency and the down bit frequency of the selected pair.

In addition, according to another object of the embodiment of the present invention, detecting the up-bit frequency, down-bit frequency and the Doppler frequency using the transmission signal and the reception signal of the radar for the plurality of frequency-converted target; Selecting a pair of up bit frequency and down bit frequency using the up bit frequency, the down bit frequency, and the Doppler frequency; And calculating distances and speeds for the plurality of targets using the up bit frequency and the down bit frequency of the selected pair.

According to still another object of the present invention, there is provided a computer-readable recording medium having recorded thereon a program for realizing the above-described distance velocity detecting method.

As described above, according to an embodiment of the present invention, when detecting distances and speeds for a plurality of targets using a radar, correlated bit frequencies can be detected from a combination of all possible bit frequencies, The distance and velocity with respect to the target can be detected accurately and efficiently.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used to refer to the same components as much as possible even if displayed on different drawings. In addition, in describing the embodiments of the present invention, if it is determined that the detailed description of the related well-known configuration or function interferes with the understanding of the embodiments of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but between components It will be understood that may be "connected", "coupled" or "connected".

A conventional frequency modulated continuous wave (FMCW) radar (hereinafter referred to as an FMCW radar) modulates frequency with time in the form of a triangular wave.

1 is an exemplary diagram showing a waveform of an FMCW radar for a single target in the form of a triangular wave expressed in the frequency-time domain.

은 변조 주기(Modulation Period)를 나타내며,

는 지연 시간(Latency Time)를 나타내며,

는 도플러 주파수(Doppler Frequency)를 나타낸다.1A shows a change in frequency of a Tx signal in a frequency-time domain and a Rx signal reflected from one moving object, that is, a single target. The FMCW radar transmits a frequency modulated continuous microwave signal. The typical modulation shape of an FMCW radar is a triangular wave. In 1A, B denotes a modulation bandwidth,

Represents a modulation period,

Represents the latency time,

Denotes the Doppler Frequency.

는 업 비트 주파수(Up-Beat Frequency)로서, 업 첩(Up Chirp)에 해당하는 비트 주파수를 나타내며,

는 다운 비트 주파수(Down-Beat Frequency)로서, 다운 첩(Down Chirp)에 해당하는 비트 주파수를 나타낸다.1B represents a beat frequency expressed as a frequency difference between a transmission signal and a reception signal.

Is an Up-Beat Frequency, and represents a bit frequency corresponding to an Up Chirp.

Is a down-bit frequency and represents a bit frequency corresponding to a down chirp.

와 도플러 주파수(Doppler Frequency)

라고 하는데, 업 비트 주파수 및 다운 비트 주파수는 수학식 1과 수학식 2와 같이 거리 비트 주파수와 도플러 주파수의 조합으로 나타낼 수 있다.The up beat frequency and the down beat frequency include frequency shifts by the distance and relative speed of the moving target. Each of these components has a range beat frequency

And Doppler Frequency

The up bit frequency and the down bit frequency may be represented by a combination of the distance bit frequency and the Doppler frequency as shown in Equation 1 and Equation 2.

는 타겟이 레이더를 향해 다가오고 있음을 나타내고, 양의 값을 가지는

는 타겟이 레이더로부터 멀어지고 있음을 나타낸다. 결국, 타겟의 거리 및 속도는

와

의 값을 이용하여 각각 계산될 수 있다.Negative

Indicates that the target is approaching the radar and has a positive value

Indicates that the target is moving away from the radar. Finally, the distance and speed of the target

Wow

Each can be calculated using the value of.

다이어그램(Diagram)을 나타낸 예시도이다.2 shows two targets measured by the up and down chirps.

Exemplary diagram showing a diagram.

다이어그램으로도 표현할 수 있다.In an environment where a plurality of targets exist in front of or around the radar, several up-bit frequencies and down-bit frequencies may be detected, resulting in ambiguity in simultaneously detecting the distance and speed of the target. As shown in FIG. 2,

It can also be represented as a diagram.

) 및 제 2 업 비트 주파수(

)와 양의 기울기를 가지는 점선으로 표시되는 제 1 다운 비트 주파수(

)와 제 2 다운 비트 주파수(

)는 타겟의 거리 및 속도의 모든 가능한 조합을 나타낸다. 여기서, 두 개의 실제 타겟(제 1 실제 타겟 및 제 2 실제 타겟)과 두 개의 고스트 타겟(제 1 고스트 타겟 및 제 2 고스트 타겟)이 4개의 교차점들에서 나타난다.The first upbeat frequency represented by a solid line with a negative slope (

) And the second up beat frequency (

) And the first down beat frequency (indicated by the dotted line with a positive slope)

) And the second down beat frequency (

) Represents all possible combinations of distance and velocity of the target. Here, two real targets (first real target and second real target) and two ghost targets (first ghost target and second ghost target) appear at four intersections.

In conclusion, in order to accurately detect the distance and speed of the target using FMCW radar in the environment where multiple targets exist, a new shape waveform should be applied. In fact, the upbeat frequency and A simple algorithm must be applied to select a unique pair of down beat frequencies. Therefore, as well as the actual targets as well as the ghost targets are detected, the accuracy of the detection of the distance and velocity for the plurality of targets is inferior.

3 is a block diagram schematically illustrating an apparatus for detecting a distance velocity of a target using a radar according to an embodiment of the present invention.

The apparatus for detecting the distance velocity of the target using the radar 300 according to the exemplary embodiment of the present invention is an apparatus for detecting the distance and the velocity of the target using the radar, and includes a signal converter 310, a frequency detector 320, and a correlation frequency. Candidate group detector 330, comparator 340 and distance and speed calculator 350 may be configured. The distance velocity detection device 300 may be implemented as a hardware or software module included in the FMCW radar, or may be implemented as hardware independent of the FMCW radar or as a software module embedded in the hardware.

The signal converter 310 frequency-transforms a transmission signal and a reception signal of a radar for a plurality of targets transmitted and received by a radar such as an FMCW radar. The signal converter 310 may be a converter that performs a Discrete Fourier Transform (FFT) such as a Fast Fourier Tramsform (FFT).

The frequency detector 320 detects the up bit frequency, the down bit frequency, and the Doppler frequency by using the transmission signal and the reception signal which are frequency converted by the signal converter 310. To this end, the frequency detector 320 may include an up bit frequency detector 322, a down bit frequency detector 324, and a Doppler frequency detector 326 as shown. Here, the up bit frequency refers to a frequency expressed as a frequency difference between a frequency-converted transmission signal and a frequency-converted received signal corresponding to an up-comb, and the down-bit frequency is frequency-converted to a frequency-converted transmission signal corresponding to a down-comb. The frequency represented by the frequency difference of the received signal, and the Doppler frequency refers to the shifted frequency between the transmission signal and the received signal according to the relative speed.

The correlation frequency candidate group detector 330 detects the correlation frequency candidate group by using the upbit frequency and the Doppler frequency detected by the frequency detector 320. To this end, the correlation frequency candidate group detector 330 may include a plurality of correlation frequency candidate group detectors, such as the first correlation frequency candidate group detector 332 to the i-th correlation frequency candidate detector 336.

The comparator 340 compares the correlated frequency candidate group detected by the correlated frequency candidate group detector 330 with the down bit frequency detected by the frequency detector 320, and has a correlated frequency candidate having the same value as the down bit frequency among the correlated frequency candidate groups. Select to select a pair of upbit frequency and downbit frequency for the selected correlation frequency candidate. To this end, the comparator 340 may include a first comparator 342 to the i th comparator 346.

The distance and speed calculator 350 calculates distances and speeds for the plurality of targets using the up and down bit frequencies of the pair selected by the comparator 340. To this end, the distance and speed calculator 350 votes a table for the pair selected by the comparator 340 to generate a pairing table and uses the pairing table to determine the distance and the number of targets. You can calculate the speed.

In addition, the frequency detector 322 may further detect the power spectral density (PSD) of the up-bit frequency and the power spectral density of the down-bit frequency, and the distance and speed calculator 350 may include the comparator 340. Among the selected pairs of the pairing table generated by voting for the pair selected by, the power spectral density of the up bit frequency and the power spectral density of the down bit frequency are the same or similar (that is, the power spectral density of the up bit frequency and the power of the down bit frequency). Additional votes for one pair of pairs (where the difference in spectral density is less than or equal to the preset threshold) to update the pairing table, and after detecting the plurality of targets using the updated pairing table, the distance to the plurality of detected targets And speed can be calculated.

Hereinafter, a process of detecting a distance and a speed of a plurality of targets by using the FMCW radar by the apparatus for detecting distance according to an embodiment of the present invention will be described with reference to FIGS. 4 to 10.

4 is an exemplary diagram illustrating a waveform of an FMCW radar signal for a single target having a trapezoidal shape expressed in the frequency-time domain.

4A exemplarily shows a frequency of a transmission signal and a reception signal having a trapezoidal signal waveform, and 4B shows an upbit frequency, a downbeat frequency, and a frequency corresponding to the frequency of the reception signal and the reception signal shown in 4A. Doppler frequency is shown as an example.

와

의 유일한 페어를 결정하는 것이 쉽지 않다. 즉, 수학식 3과 수학식 4로 표현되는 모든 조합이

와

사이의 모호성을 초래하게 된다.As mentioned earlier, the signal waveform of an FMCW radar with up and down chirp signals is used for the actual target.

Wow

Is not easy to determine the only pair. That is, all combinations represented by equations (3) and (4)

Wow

Will lead to ambiguity between them.

는 i번째 업 비트 주파수이고,

는 j번째 다운 비트 주파수 이며, i=1~n, j=1~m, n=1~N, m=1~N이고, N은 검출해야 하는 타겟의 개수이다.here,

Is the i th upbeat frequency,

Is the j th down bit frequency, i = 1 to n , j = 1 to m , n = 1 to N , m = 1 to N , and N is the number of targets to be detected.

의 정확한 페어를 조합하기 위해서는 부가적으로 비변조 연속 파형(UCW: Unmodulated Continuous Wave)이 필요하며, 비변조 연속 파형으로 가장 널리 알려진 신호 파형의 모양이 4A에 나타낸 바와 같은 사다리꼴 모양이다. 도플러 주파수가 비변조 연속 파형에서 검출되기 때문에, 수학식 3과 수학식 4에 나타난

와

사이의 모호성은 수학식 5와 같이 해결 될 수 있다.Of each target Wow

In order to combine the correct pairs of, additionally an unmodulated continuous wave (UCW) is required, and the shape of the signal waveform most commonly known as an unmodulated continuous waveform is trapezoidal as shown in 4A. Since the Doppler frequency is detected in the unmodulated continuous waveform, the equations (3) and (4)

Wow

The ambiguity between can be solved as in Equation 5.

Here, k = 1 ~ l , l = 1 ~ N , and N is the number of targets to be detected.

다이어그램의 예시도이다.5 shows three targets measured by signals of an unmodulated continuous waveform.

It is an example diagram of a diagram.

다이어그램을 예시적으로 나타내었다. 타겟은 업 비트 주파수, 다운 비트 주파수와 도플러 주파수의 교차점에의해 검출될 수 있다. 만약, 비변조 연속 파형이 적용되지 않은 경우 즉, 삼각파 모양의 신호 파형이 적용 된 경우라면, 도시한 바와 같이 5 개의 고스트 타겟들이 비트 주파수의 페어링(Pairing)을 통해 검출될 수 있다. 따라서, 비변조 연속 파형의 신호를 송수신하는 FMCW 레이더를 이용하면 복수 개의 타겟이 존재하는 환경에서 오류로서 검출되는 고스트 타겟의 개수를 줄일 수 있으므로 더욱 정확하게 실제 타겟을 검출할 수 있다.In FIG. 5, bit frequencies are received from three targets through a trapezoidal signal waveform.

The diagram is shown by way of example. The target may be detected by the intersection of the up beat frequency, the down beat frequency and the Doppler frequency. If a non-modulated continuous waveform is not applied, that is, a triangular wave shaped signal waveform is applied, five ghost targets may be detected through pairing of bit frequencies as shown. Therefore, by using the FMCW radar that transmits and receives a signal of an unmodulated continuous waveform, the number of ghost targets detected as an error can be reduced in an environment where a plurality of targets exist, so that the actual target can be detected more accurately.

가 검출되면 그로 인해 비트 주파수들의 가능한 조합들이 많아져 정확한 조합을 찾아내는 과정이 다소 복잡해진다는 점이다.However, FMCW radars with unmodulated continuous waveforms may have other problems.

Is detected, this increases the number of possible combinations of bit frequencies, making the process of finding the correct combination somewhat complicated.

In addition, although the FMCW radar having the trapezoidal signal waveform is lower than the FMCW radar having the triangular signal waveform, the ghost target may still be detected. In other words, when pairing the up bit frequency and the down bit frequency by using the detected plurality of Doppler frequencies, there is still a probability that a plurality of solutions, rather than unique pairs, appear as in Equation 5. In addition, signals reflected from two or more targets appear at the up and down bit frequencies, such as Equations 1 and 2, under the influence of the Doppler frequency shift, resulting in missing targets.

In order to overcome these problems, in one embodiment of the present invention, to remove the ghost target and recover the missing target, an up-bit frequency is used as the reference frequency to detect a correlation frequency candidate group in relation to the Doppler frequency and the correlation frequency. A method of generating a pairing table by voting one vote for the up-bit frequency and the down-bit frequency if there is an identical or similar value by comparing the candidate group with the down-bit frequency, and detecting the actual target by using the pairing table. Use

를 참조 주파수로 사용한다. 먼저, 참조 주파수와 도플러 주파수

를 수학식 5에 적용하여, 상관 주파수 후보군

를 수학식 6과 수학식 7과 같이 구한다. That is, in the pairing algorithm according to an embodiment of the present invention, the upbit frequency

Is used as the reference frequency. First, the reference frequency and the Doppler frequency

Is applied to Equation 5, the correlation frequency candidate group

Is obtained as shown in Equations 6 and 7.

와 다운 비트 주파수

를 비교하여 같은 값이 존재하는 경우 해당하는

와

의 페어에 한 표(voting)를 주어 페어링 테이블을 생성한다. 예를 들어,

와

의 값이 같다면,

를 검출할 때 사용된 업비트 주파수가

이라면,

와

의 페어에 한 표를 투표한다.to the next,

And down beat frequency

To compare the corresponding values if they exist

Wow

Create a pairing table by giving a vote to the pair of. E.g,

Wow

If the values of are equal,

The upbit frequency used when detecting

If

Wow

Vote for a pair of votes.

다이어그램을 나타낸 예시도이다.6 shows four targets measured by signals of an unmodulated continuous waveform.

An illustration showing a diagram.

다이어그램을 예시적으로 나타나내면 도 6과 같이 나타낼 수 있다. 도 6에서는 FMCW 레이더의 검출 영역 내에서 두 개의 고스트 타겟이 나타난 경우이다. 즉,

및

페어와

및

페어가 각각 고스트 타겟으로 나타났다. 이와 같이, 본 발명의 일 실시예에 따른 페어링 알고리즘에 따라 타겟을 검출하면 업 비트 주파수와 다운 비트 주파수의 모든 교차점 중 도플러 주파수와ㅏ 교차하는 교차점만이 타겟으로 검출될 수 있으므로, 검출되는 고스트 타겟의 개수를 줄일 수 있다.For four targets according to the pairing algorithm described above

If the diagram is shown by way of example it can be shown as shown in FIG. In FIG. 6, two ghost targets appear in the detection area of the FMCW radar. In other words,

And

Fair and

And

Each pair appeared as a ghost target. As such, when the target is detected according to a pairing algorithm according to an embodiment of the present invention, only an intersection point intersecting with the Doppler frequency among all intersection points of the up bit frequency and the down bit frequency may be detected as the target, and thus the detected ghost target The number of can be reduced.

7 is an exemplary diagram illustrating a pairing table for four targets measured by a signal of an unmodulated continuous waveform.

,

, 그리고

는 상관 관계가 있는 다운 비트 주파수 또는 업 비트 주파수가 각각 2 개임을 알 수 있다. 7B는 페어링이 완성된 후의 페어링 테이블을 나타낸 것이다. 만약, 업 비트주파수와 다운 비트 주파수가 각각 1 개씩만 페어링될 수 있다고 가정하면, 업 비트 주파수 및 다운 비트 주파수의 유일한 조합은 7B와 같이 완성될 수 있다. 즉,

과

의 페어와

와

의 페어를 제거함으로써, 7B와 같이 타겟을 검출할 수 있다.7A shows a pairing table generated by voting. Through the pairing table shown in 7A,

,

, And

It can be seen that there are two correlated down beat frequencies or up beat frequencies. 7B shows a pairing table after pairing is completed. If it is assumed that only one up bit frequency and one down bit frequency can be paired, the only combination of the up bit frequency and the down bit frequency can be completed as shown in 7B. In other words,

and

With a pair of

Wow

By removing the pair of, the target can be detected as in 7B.

However, not only the exact number of actual targets is known from the information of the up-bit frequency and the down-bit frequency detected in this way, but also it is determined whether each combination of the up-bit frequency and the down-bit frequency is a real target or a ghost target. Can not.

다이어그램을 나타낸 예시도이다.8 shows another example of four targets measured by a signal of another example unmodulated continuous waveform.

An illustration showing a diagram.

,

, 및

로 표현된다.

를 이용하여

와

의 가능한 조합에 투표하여 페어링 테이블을 생성하면, 도 9에 도시한 바와 같이, 생성될 수 있다.In Fig. 8, the up bit frequency, the down bit frequency and the Doppler frequency are respectively

,

, And

It is expressed as

Using

Wow

When a pairing table is generated by voting on a possible combination of, as shown in FIG. 9, it may be generated.

9 is an exemplary diagram illustrating a pairing table for four targets measured by signals of another example unmodulated continuous waveform.

9A shows a pairing table generated through voting, and 9B and 9C show pairing tables completed by determining pairs from the pairing table generated in 9A, respectively.

According to the example described above with reference to FIG. 8, a pairing table may be generated as shown in 9A. However, as shown in 9A, since there are two down bit frequencies that can be paired with all up bit frequencies, it is not possible to determine a unique pair for each target. Therefore, using only the up bit frequency and the down bit frequency cannot accurately determine the number of actual targets and the distance and speed of the actual targets. In particular, when the number of detected bit frequencies is smaller than the number of actual targets, it is naturally more difficult to detect the distance and speed of all actual targets.

에서 겹쳐서 나타나고, 타겟 C와 타겟 D로부터 반사된 신호 역시 같은 다운 비트 주파수

에서 겹쳐서 나타난다. 이 경우, 9B와 9C와 같이 업-비트 및 다운-비트 주파수의 페어를 결정 할 수 밖에 없다. 9B에서는 타겟 C만이 정확하게 검출되고, 타겟 A와 타겟 B가 검출되지 않아 미싱 타겟으로 남았으며, 나머지 검출된 타겟들은 고스트 타겟이 실제 타겟으로 검출되었다. 또한, 9C에서는 타겟 A와 타겟 B는 제대로 검출되었으나, 타겟 C는 검출되지 않아 미싱 타겟으로 남았다.For example, as shown in FIG. 8, the upbit frequencies of the signals received from the target A and the target C are the same frequency position.

Overlapped at, and the signals reflected from target C and target D also have the same downbit frequency

Appears superimposed on In this case, there is no choice but to determine the pair of up-bit and down-bit frequencies as in 9B and 9C. In 9B, only target C was correctly detected, target A and target B were not detected, and remained as missing targets. The remaining detected targets were detected as ghost targets. In addition, in 9C, target A and target B were properly detected, but target C was not detected and remained as a missing target.

In order to solve this problem, in one embodiment of the present invention, as described above, in addition to a pairing algorithm for selecting a pair by creating a pairing table, the pair is added to the voted pair of the pairing table using the power spectral density of the received signal. By voting more votes, the pairing table can be updated, and the target can be detected using the updated pairing table.

It can be said that the up bit signal and the down bit signal received from one target have the same power spectral density. This property is used to vote again for a pair of upbit frequency and downbit frequency selected by the first voting, that is, a pair that has a high correlation by power spectrum density among the selected pair.

10 is an exemplary diagram illustrating an updated pairing table using a power spectral density.

In the example described above with reference to FIGS. 8 and 9, when the pairing table is updated using the power spectral density, the pairing table may be represented as shown in FIG. 10.

10A shows an example of the power spectral density of the upbit frequency and downbit frequency, 10B shows the pairing table updated by further voting to the high correlation pair using the power spectral density, 10C is the update The result of detecting a target using the pairing table which was shown is shown.

와

의 전력 스펙트럼 밀도가 같은 값을 가진다고 가정하면, 두 개의 비트 주파수에 상응하는 비트 신호들이 하나의 타겟(타겟 B)로부터 수신된 것으로 결정할 수 있다. 이를 통해,

페어만이 10B와 같이 추가적인 한 표를 얻을 수 있으며,

와

가 불가능한 페어라는 것도 알 수 있으므로,

페어와

페어는 페어링 테이블에서 삭제하여 제거할 수 있다. 또한, 다른 업 비트 주파수 및 다운 비트 주파수들의 전력 스펙트럼 밀도는 서로 다르기 때문에,

와

는 각각 두 개의 타겟으로부터 수신된 비트 주파수라고 할 수 있다. 이를 이용하여 10B의 업데이트된 페어링 테이블에서타겟을 검출하면 10C와 같이 타겟 A, B, C, D가 검출될 수 있다. 이와 같이, 전력 스펙트럼 밀도를 이용하면, 선택된 페어들 중에서 동일한 타겟으로부터 수신된 것들을 결정할 수 있으므로, 고스트 타겟과 미싱 타겟을 줄일 수 있다.As shown in 10A,

Wow

Assuming that the power spectral densities of have the same value, it can be determined that the bit signals corresponding to the two bit frequencies have been received from one target (target B). because of this,

Only the pair gets an extra vote, like 10B,

Wow

It is also known that the pair is impossible,

Fair and

Pairs can be removed by deleting them from the pairing table. Also, since the power spectral densities of the different up and down bit frequencies are different,

Wow

Each may be referred to as a bit frequency received from two targets. If the target is detected in the updated pairing table of 10B using this, targets A, B, C, and D may be detected as in 10C. As such, using the power spectral density, it is possible to determine those received from the same target among the selected pairs, thereby reducing the ghost target and the missing target.

11 is a flowchart illustrating a method for detecting a distance velocity of a target using a radar according to an embodiment of the present invention.

When the distance speed detecting apparatus 300 according to an embodiment of the present invention receives a transmission signal and a reception signal of an FMCW radar for a plurality of targets, frequency conversion is performed, and the transmission signal and reception of the radar for a plurality of frequency-converted targets are received. The signal is used to detect the upbit frequency, the downbit frequency and the Doppler frequency, and the pair of the upbit frequency and the downbit frequency is selected using the upbit frequency, the downbit frequency and the Doppler frequency, and the upbit frequency of the selected pair. And calculating distances and velocities for the plurality of targets using the down beat frequency, thereby detecting distances and velocities for the plurality of targets.

Here, in selecting the pair, the distance velocity detecting apparatus 300 uses the upbit frequency and the Doppler frequency as described above through Equation 5, Equation 6, and Equation 7 in FIG. Is detected, and a pair of up-bit frequencies and down-bit frequencies may be selected for a correlation frequency candidate having the same value as the down-bit frequency among the correlation frequency candidate groups by comparing the down-bit frequencies.

와

를 페어링 테이블에서 제거하여 선택된 페어를 줄임으로써 10C와 같이 고스트 타겟을 줄여 실제 타겟의 검출 가능성을 높일 수 있다.In addition, the distance speed detecting apparatus 300 reduces the number of selected pairs based on the power spectral density of the up-bit frequency and the down-bit frequency of the selected pair in calculating distance and speed, and reduces the number. The distance and speed for the plurality of targets may be calculated using the up bit frequency and the down bit frequency of the selected pair. That is, the distance velocity detecting device 300 is an impossible pair in the updated pairing table shown in 10B.

Wow

By removing the from the pairing table to reduce the selected pair, the ghost target can be reduced, as in 10C, to increase the detection probability of the actual target.

To this end, the distance velocity detecting apparatus 300 generates a pairing table by voting one vote to the selected pair, as described above with reference to FIG. 10, in calculating distance and speed, and among the voted pairs of the pairing table. Update the pairing table by voting an additional vote on the pair where the power spectral density of the up-bit frequency and the power spectral density of the down-bit frequency are less than or equal to the preset threshold, and update the pairing table using the updated pairing table. You can calculate the speed.

As such, the method of detecting the distance and the speed of the plurality of targets by the distance velocity detecting apparatus 300 may be illustrated in FIG. 11.

That is, the distance velocity detecting apparatus 300 detects the up bit frequency, the down bit frequency, and the Doppler frequency from the transmission signal and the reception signal of which the transmission signal and the reception signal of the FMCW radar for the plurality of targets are frequency converted. Thereafter, the distance velocity detecting apparatus 300 sets the upbit frequency as the reference frequency, and detects a correlation frequency candidate group using the reference frequency and the Doppler frequency (S1110). Here, the distance velocity detecting apparatus 300 may detect the correlation frequency candidate group by applying the reference frequency and the Doppler frequency to Equation 5.

In addition, the distance velocity detecting apparatus 300 compares the downlink frequency with the correlation frequency candidate group (S1120), and determines whether the same correlation frequency as the downbit frequency exists in the correlation frequency candidate group (S1130).

As a result of the determination in step S1130, when the distance velocity detecting apparatus 300 has a correlation frequency equal to the down bit frequency among the correlation frequency candidate groups, the distance velocity detecting apparatus 300 shows one table in the pair of the up bit frequency corresponding to the same correlation frequency and the same down bit frequency. By voting to create a pairing table (S1140).

The distance speed detecting apparatus 300 may detect the distance and the speed with respect to the target using the generated pairing table. That is, the distance bit rate and the Doppler frequency for the target are calculated by substituting the up bit frequency and the down bit frequency of the selected pair of the generated pairing table into Equation 3 and Equation 4. Can be detected.

However, in this case, as described above with reference to FIGS. 6 to 8, since the actual target may not be detected or the ghost target may be detected, the distance and the speed may be detected after detecting the target using the power spectral density. .

That is, the distance velocity detecting apparatus 300 further votes one vote on the pair having a high correlation by the power spectral density of the upbit frequency and the downbit frequency among the selected pairs of the pairing table generated in step S1140 to pair the pairing table. After updating (S1150), the distance and speed of the target may be detected using the updated pairing table (S1160).

12 is an exemplary view illustrating a simulation example for explaining a process of detecting distances and velocities of a plurality of targets according to an embodiment of the present invention.

After setting the transmission bandwidth of the FMCW radar to 300 MHz, the center frequency to 76.5 GHz, and the modulation period to 1 ms, as shown in FIG. 12, three targets (cars B, C, and D) are running forward on the road. Assuming that the targets (car A and road sign D) are standing by the road, the distance and relative speed of the targets on the road are detected. In the case of the simulation example shown in FIG. 12, the upbit frequency, the downbit frequency, and the Doppler frequency calculated by the distance to the targets and the relative speed may be represented as shown in Table 1.

FIG. 13 is an exemplary diagram illustrating a bit frequency and a normalized power spectral density detected from each target of the simulation example.

In the case of the simulation example shown in FIG. 12, the bit frequency and normalized power spectral density detected from each target may be represented as shown in FIG. 13. In Figure 13, the X axis is frequency and the Y axis is normalized power spectral density.

13A shows the detected up beat frequency, down beat frequency and Doppler frequency, 13B shows the normalized power spectral density for the up chirp, and 13C shows the normalized power spectral density for the down chirp.

14 is an exemplary view showing a pairing table of a simulation example.

, 다운 비트 주파수

, 도플러 주파수

를 이용하여 투표하여 생성된 페어링 테이블을 나타낸 것이고, 14B는 전력 스펙트럼 밀도를 이용하여 업데이트된 페어링 테이블을 나타낸 것이며, 14C는 업데이트된 페어링 테이블을 이용하여 타겟을 검출한 모습을 나타낸 것이다. 도 13에서, 전력 스펙트럼 밀도

와

만이 거의 같은 값을 가지기 때문에,

페어만이 한 표를 추가로 투표받을 수 있다. 결국

와

는 각각 두 개의 타겟(타겟 A와 타겟 B, 그리고 타겟 C와 타겟 D)으로부터 수신된 신호의 비트 주파수라고 결론을 내릴 수 있다. 이와 같은 과정을 통해, 복수 개의 타겟을 위한 비트 주파수들의 페어 즉, 타겟은 14C와 검출될 수 있다.14A is the upbit frequency shown in FIG.

Downbeat frequency

Doppler frequency

Shows a pairing table generated by voting using, 14B shows an updated pairing table using the power spectral density, and 14C shows a target detected using the updated pairing table. In Figure 13, the power spectral density

Wow

Because only about the same value,

Only a pair may receive one additional vote. finally

Wow

It can be concluded that is the bit frequency of the signal received from the two targets (target A and target B, and target C and target D), respectively. Through this process, a pair of bit frequencies for a plurality of targets, that is, the target may be detected with 14C.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, although all of the components may be implemented in one independent hardware, each or all of the components may be selectively combined to perform some or all functions combined in one or a plurality of hardware. It may be implemented as a computer program having a. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art. Such a computer program may be stored in a computer readable storage medium and read and executed by a computer, thereby implementing embodiments of the present invention. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, a carrier wave medium, and the like.

In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be inherent unless specifically stated otherwise, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms used generally, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be interpreted in an ideal or excessively formal sense unless explicitly defined in the present invention.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 is an exemplary diagram showing a waveform of an FMCW radar for a single target in the form of a triangular wave expressed in the frequency-time domain.

다이어그램(Diagram)을 나타낸 예시도,2 shows two targets measured by the up and down chirps.

Exemplary diagram showing a diagram,

3 is a block diagram schematically illustrating an apparatus for detecting a distance velocity of a target using a radar according to an embodiment of the present invention;

4 is an exemplary diagram showing a waveform of an FMCW radar signal for a single target having a trapezoidal shape expressed in the frequency-time domain.

다이어그램의 예시도,5 shows three targets measured by signals of an unmodulated continuous waveform.

Illustrative diagram of the diagram,

다이어그램을 나타낸 예시도,6 shows four targets measured by signals of an unmodulated continuous waveform.

Illustrated diagram showing a diagram,

7 is an exemplary diagram showing a pairing table for four targets measured by a signal of an unmodulated continuous waveform;

다이어그램을 나타낸 예시도,8 shows another example of four targets measured by a signal of another example unmodulated continuous waveform.

Illustrated diagram showing a diagram,

9 is an exemplary diagram showing a pairing table for four targets measured by a signal of another example unmodulated continuous waveform;

10 is an exemplary diagram illustrating an updated pairing table using a power spectral density;

11 is a flowchart illustrating a method for detecting a distance velocity of a target using a radar according to an embodiment of the present invention;

12 is an exemplary view showing a simulation example for explaining a process of detecting distance and velocity for a plurality of targets according to an embodiment of the present invention;

13 is an exemplary diagram showing a bit frequency and a normalized power spectral density detected from respective targets of a simulation example;

14 is an exemplary view showing a pairing table of a simulation example.

<Description of Symbols for Main Parts of Drawings>

310: signal converter 320: frequency detector

330: correlation frequency candidate group detector 340: comparator

350: distance and speed calculator

Claims (9)

A signal converter for frequency converting the transmission signal and the reception signal of the radar for the plurality of targets; A frequency detector for detecting an upbit frequency, a downbit frequency, and a Doppler frequency using the frequency-converted transmission signal and the reception signal; A correlation frequency candidate group detector configured to detect a correlation frequency candidate group using the upbit frequency and the Doppler frequency; A comparator comparing the correlation frequency candidate group with the down bit frequency and selecting a pair of an up bit frequency and a down bit frequency for a correlation frequency candidate having the same value as the down bit frequency among the correlation frequency candidate group; And A distance and speed calculator for calculating distances and speeds for the plurality of targets using up and down bit frequencies of the selected pair; The distance and speed calculator, Voting one vote for the selected pair to generate a pairing table and calculating distance and speed for the plurality of targets using the pairing table. delete The method of claim 1, wherein the frequency detector, And detecting the power spectral density of the up-bit frequency and the power spectral density of the down-bit frequency. The method of claim 3, wherein the distance and speed calculator, Update the pairing table by further voting one vote for a pair of the selected pair of the pairing table whose difference between the power spectral density of the up bit frequency and the power spectral density of the down bit frequency is equal to or less than a preset threshold; And a distance and velocity for the plurality of targets using the paired table. delete Detecting an up bit frequency, a down bit frequency, and a Doppler frequency using a transmission signal and a reception signal of a radar for a plurality of frequency-converted targets; Selecting a pair of up bit frequency and down bit frequency using the up bit frequency, the down bit frequency and the Doppler frequency; And Calculating distances and velocities for the plurality of targets using up and down bit frequencies of the selected pair; Selecting the pair, Detecting a correlation frequency candidate group using the upbit frequency and the Doppler frequency; And Comparing the correlation frequency candidate group with the down bit frequency and selecting a pair of an up bit frequency and a down bit frequency for a correlation frequency candidate having the same value as the down bit frequency among the correlation frequency candidate group. Distance speed detection method. Detecting an up bit frequency, a down bit frequency, and a Doppler frequency using a transmission signal and a reception signal of a radar for a plurality of frequency-converted targets; Selecting a pair of up bit frequency and down bit frequency using the up bit frequency, the down bit frequency and the Doppler frequency; And Calculating distances and velocities for the plurality of targets using up and down bit frequencies of the selected pair; The step of calculating the distance and speed, Reducing the number of the selected pair based on the power spectral density of the up bit frequency and the power spectral density of the down bit frequency of the selected pair; And Calculating distance and velocity for the plurality of targets using the up-bit frequency and down-bit frequency of the reduced number of selected pairs. Detecting an up bit frequency, a down bit frequency, and a Doppler frequency using a transmission signal and a reception signal of a radar for a plurality of frequency-converted targets; Selecting a pair of up bit frequency and down bit frequency using the up bit frequency, the down bit frequency and the Doppler frequency; And Calculating distances and velocities for the plurality of targets using up and down bit frequencies of the selected pair; The step of calculating the distance and speed, Voting one vote on the selected pair to generate a pairing table; Voting an additional table in a voted pair of the pairing table, wherein the power spectral density of the up-bit frequency and the power spectral density of the down-bit frequency are equal to or less than a preset threshold to update the pairing table; And And calculating distances and velocities for the plurality of targets using the updated pairing table. A computer-readable recording medium having recorded thereon a program for realizing the distance velocity detecting method according to any one of claims 6 to 8.

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