KR101240415B1 - Method for processing sidelobe blanking in adaptive array radar - Google Patents

Abstract

PURPOSE: An SLB(Side Lobe Blanking) processing method for adaptive array radars is provided to reduce costs by blocking signals flowing through side lobes with software without using assistant antennas. CONSTITUTION: Signals flowing through array antenna elements are converted into baseband signals(S300,S310). An estimated incident angle is generated and coherent energy is calculated by using the estimated incident angle or the baseband signals(S320,S330). Non-coherent energy is calculated by using the baseband signals(S311). An energy ratio is calculated by using the calculated coherent energy and non-coherent energy(S340). The calculated energy ratio is compared with a threshold value(S350). If the calculated energy ratio is bigger than the threshold value, the estimated incident angle is considered to be inside a main lobe and a data processor processes the inputted signals(S350,S350-1). If the calculated energy ratio is smaller than the threshold value, the estimated incident angle is considered to be inside a side lobe and the data processor blocks the inputted signals(S361,S371). [Reference numerals] (AA) Start; (BB) No; (CC) Yes; (DD) End; (S300) Sending a signal(S) to array antenna elements; (S310) Converting the flowing signal(S) into baseband signals(x_i); (S320) Calculating an estimated incident angle(θ^^); (S330) Calculating coherent energy(C); (S331) Calculating non-coherent energy(N); (S350) R > threshold value?; (S360) Determining that the estimated incident angle(θ^^) is inside a main lobe; (S361) Determining that the estimated incident angle(θ^^) is inside a side lobe; (S370) Processing in a data processor; (S371) No processing

Description

Method for processing Sidelobe Blanking in adaptive array radar

The present invention relates to a method for processing an SLB of an adaptive array radar, and more particularly, to process a SLB even in the case of forming a multi-beam in an adaptive array radar using a digital beamforming technique, and does not use a separate auxiliary antenna. Therefore, since SLB is implemented, it is about SLB processing method which has advantages such as cost reduction and beam time between failures (MTBF).

In the radar, SLB (Side Lobe Blanking) is a method in which the radio waves reflected from the target and coming into the antenna do not enter the mainlobe of the main antenna but enter the sidelobe so that they are not used as detection information.

In the existing SLB method, the SLB is processed by installing an auxiliary antenna in addition to the main antenna. In this case, the SLB antenna is implemented so that the gain of the radiation pattern of the auxiliary antenna is lower than that of the main antenna and higher than that of the main antenna in order to maximize the detection probability in the main lobe and minimize the detection probability in the sublobe.

This SLB structure should be designed such that the SLB antenna, which is an auxiliary antenna, also enables electronic beam steering when the main antenna of the radar steers the electronic beam.

Considering only the antenna gain side, the radiation pattern of the SLB antenna must always be higher than the gain of the main antenna's side lobe in order to block the incoming signal to Sidelobe. In an electronic beam steering radar, this SLB antenna design is obtained through many trials Hardware manufacturing and testing costs are high.

With the development of radar, adaptive array antennas for digital beamforming are driving modern radar. In such radar, the SLB method is a method of generating a SLB signal by reusing a part of sub-array received signals without a separate auxiliary antenna.

A sum channel and a difference channel can be generated by a digital beamforming technique using the received signal of the phased array antenna. In this case, the sum channel is used as a signal for detecting a target as in the case of a normal radar, and there is a technology that processes the SLB using the difference channel as if it is a signal generated from the auxiliary antenna without the auxiliary antenna.

The difference channel signal pattern obtained by the beamforming method is designed to have a low gain in the main lobe region and a high gain in the sublobe region, thereby blocking a signal flowing into the sublobe (Sidelobe).

However, when the multi-beams are formed using the signals of the array antenna, the difference in channel pattern characteristics is severely changed, and thus the difference in channel pattern gain is lower than the side lobe gain. In this case, the probability of blocking the incoming signal to Sidelobe is reduced.

1. Kwan-Hyung Lee, Woo-Young Song, Myung-Ho "A Study on the Estimation of Orientation Error and the Estimation of Adaptive Array Incident Direction", Vol.16 No. 9, 2011.9. 2. Kwan-Hyung Lee, Woo-Young Song "A Study on the Target Location Algorithm in the Radar System," Journal of the Korea Society of Computer and Information, Vol. 13, No. 5, 2008.9. 3. Seung-Kwan Ahn, Sang-Jung Lee "A Study on the Beam Shape Adjustment of Adaptive Array Antenna for Satellite Navigation Receiver", Vol. 9, No. 2, June 2006

The present invention has been proposed to solve the problems according to the prior art, and can be used in an adaptive array radar using a digital beamforming technique, and even when forming multiple beams, SLB (Sidelobe Blanking) processing is easy and separate. The object of the present invention is to provide a method for processing an SLB of an adaptive array radar that can be implemented in software without using an auxiliary antenna.

The present invention provides a method for processing SLB (Sidelobe Blanking) of an adaptive array radar that can be implemented in software without using a separate auxiliary antenna in order to achieve the object raised above.

The SLB processing method of the adaptive array radar includes: a signal conversion step of converting an incoming signal introduced into the array antenna element into a baseband signal; An estimated incidence angle calculation step of calculating an estimated incidence angle at which the incoming signal is incident on the converted baseband signal using a maximum likelihood algorithm; Calculating a tuning energy using the converted baseband signal and the calculated estimated incidence angle; An untuned energy calculation step of calculating untuned energy using the converted baseband signal; Calculating an energy proportional value by dividing the tuning energy by untuned energy to calculate an energy proportional value; Determining an energy proportional value magnitude that determines whether the energy proportional value is greater than a threshold value; A signal processing step of processing the incoming signal if the estimated incidence angle is in the main lobe if the result is greater than a threshold value; And a signal blocking step of blocking the inflow signal by determining that the estimated incidence angle is in the side lobe if the threshold value is smaller than the threshold value.

에 의해 산출되는 것을 특징으로 할 수 있다. 여기서,

는 유입신호(

>0)이고,

이고,

이고,

는 송신 주파수의 파장이고,

는 배열 안테나 소자간의 거리이고,

는 배열 안테나 소자로 복사되어 유입되는 신호의 입사각이고,

는

를 나타낸다.In this case, the baseband signal is the following equation,

. here,

Is the incoming signal (

> 0),

ego,

ego,

Is the wavelength of the transmission frequency,

Is the distance between the array antenna elements,

Is the angle of incidence of the signal radiated and introduced into the array antenna element,

The

Indicates.

로 표시되며, 상기 기저대역신호 벡터를 조향 벡터로 표시하면, 다음식,

으로 표시되는 것을 특징으로 할 수 있다.In addition, the baseband signal is represented by a vector, the baseband signal vector represented by a vector is represented by the following equation,

Represented by the steering vector, the following equation,

It may be characterized as represented by.

으로 표시되는 것을 특징으로 할 수 있다. 여기서,

는 노이즈를 나타내며, 재머 및 열잡음을 모두 포함할 수 있다. In addition, the baseband signal vector is the following equation,

It may be characterized as represented by. here,

Represents noise and may include both jammer and thermal noise.

에 의해 산출되는 것을 특징으로 할 수 있다. 여기서,

는 추정 입사각으로 입사각

을 추정한 추정 입사각을 나타내고,

는

의 역행렬로서,

이고, H는 공액 전치(conjugate transpose)를 나타내고,

는 기저대역신호 벡터를 나타낸다.In addition, the tuning energy is

. here,

Is the incident angle as the estimated incident angle

Represents an estimated incidence angle estimated by

The

As the inverse of,

H represents conjugate transpose,

Denotes the baseband signal vector.

에 의해 산출되는 것을 특징으로 할 수 있다.In addition, the non-tuned energy is the following equation,

.

에 의해 산출되는 것을 특징으로 할 수 있다.In addition, the energy proportional value is the following equation,

.

의 값은 입사각

의 추정값인 입사각 추정값

가 부엽에서 유입된 것인지 아니면 주엽에서 유입된 것인지를 판단한 test statistics 으로 사용되는 것을 특징을 한다.here,

Is the angle of incidence

Angle of incidence

It is characterized by being used as test statistics to determine whether the inflow from the side lobe or the main lobe.

According to the present invention, a radar using adaptive array processing does not require a separate auxiliary antenna for the SLB, and can cut hardware costs by software blocking a signal flowing into the side lobe, and does not cause a problem of failure. There is no advantage.

Another effect of the present invention is that the present invention can be applied to similar equipment such as radar and sonar.

1 is a conceptual diagram of a SideLobe Blanking (SLB) processing algorithm according to an embodiment of the present invention.
FIG. 2 is a flowchart for easily understanding an SLB process of the adaptive array radar shown in FIG. 1.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term “and / or” includes any combination of a plurality of related items or any item of a plurality of related items.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Should not.

Hereinafter, a SLB processing method of an adaptive array radar according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

)는 신호처리를 위해 기저대역(baseband) 신호로 다운 컨버젼(down conversion)된다. 1 is a conceptual diagram of a SideLobe Blanking (SLB) processing algorithm according to an embodiment of the present invention. Inflow signal introduced to the array antenna element 11 in FIG.

) Is down converted to a baseband signal for signal processing.

(12)이라 하고 배열 안테나 소자(11) 방향으로 복사되어 들어오는 유입 신호를

(여기서,

> 0)라고 할 때, 기저대역신호

는

이다. 여기서,

이고,

이고,

는 송신 주파수의 파장이고,

는 배열 안테나 소자(11)간의 거리이고,

는 배열 안테나 소자(11)로 복사되어 유입되는 실제 신호의 입사각이고

는

이다. 이를 기저대역 신호 벡터

로 표현하면 다음과 같이 나타낸다.Baseband signals (ie, signals that are downconverted to baseband)

The incoming signal radiated in the direction of the array antenna element 11 is referred to as (12).

(here,

Baseband signal

The

to be. here,

ego,

ego,

Is the wavelength of the transmission frequency,

Is the distance between the array antenna elements 11,

Is the incident angle of the actual signal radiated to the array antenna element 11 and

The

to be. Baseband signal vector

If expressed as:

[Equation 1]

,

에 의해 산출되는 것을 특징으로 할 수 있다. 조향 벡터

는 다음과 같이 나타낼 수 있다.Also, a steering vector for the SLB

,

. Steering vector

Can be expressed as:

&Quot; (2) "

를 벡터

을 사용하여 표현하면

와 같다. 일반적으로 수신기는 노이즈

가 존재하므로 기저대역 신호 벡터

는 다음식과 같이 모델링된다.vector

Vector

If you express it using

Same as Typically, the receiver is noisy

Baseband signal vector

Is modeled as

&Quot; (3) "

는 재머뿐만 아니라 열잡음까지 모두 포함되며 노이즈의 분산 및 상관관계를 공분산 행렬

을 사용하여 나타낸다. 즉

은 다음과 같다. Where noise

Includes not only jammers but also thermal noise, and the covariance matrix of noise variance and correlation

It is shown using. In other words

Is as follows.

&Quot; (4) "

는 공액 전치(conjugate transpose)를 나타낸다. Where superscript

Represents a conjugate transpose.

Further, the tuning energy C of the coherent signal and the non-tuning energy N of the untuned signal are expressed as follows.

[Equation 5]

는 입사각

의 추정값으로 추정 입사각이라 하며 ML(Maximum Likelihood) 알고리즘 방식 등을 이용하여 산출한다. 이러한 ML 방식 등은 널리 알려져 있으므로 이에 대하여는 본 발명의 명확한 이해를 위해 생략하기로 한다. here,

Is the incident angle

The estimated incidence is called the estimated incidence angle and is calculated using the ML (Maximum Likelihood) algorithm. Since such ML method is widely known, it will be omitted for clear understanding of the present invention.

That is, the present invention is to determine whether the inside of the side lobe or the main lobe with respect to the estimated angle of incidence calculated using the ML method, etc., the process of estimating the angle of incidence is already well known and will be omitted.

&Quot; (6) "

는

의 역행렬을 나타낸다. here,

The

Represents the inverse of.

(이를 에너지 비례값이라 하자)이 다음식과 같이 산출될 수 있다. Thus, the value of the ratio of coherent and noncoherent energy

The energy proportional value can be calculated as follows.

[Equation 7]

은 입사각

의 추정값인 추정 입사각

가 부엽에서 유입된 것인지 아니면 주엽에서 유입된 것인지를 판단하는 test statistics로 사용되는 것을 특징을 한다.Where energy proportional value

Silver incident angle

Estimated incidence angle

It is characterized by being used as test statistics to determine whether the inflow from the side lobe or the main lobe.

값은 1에 가까운 값을 출력하게 된다. In other words, when the signal introduced into the array antenna element 11 in FIG. 1 enters the main lobe direction (not shown).

The value will output a value close to 1.

은 0에 가까운 값을 갖게 되어 도 1에서 적절한 문턱치

를 설정하여

보다 큰 값을 갖는지 아니면 작은 값을 갖는지 확인하며 신호가 부엽으로 들어왔는지 판단할 수 있다. On the other hand, when entering the main lobe direction (not shown) without entering the main lobe

Has a value close to zero, so that the appropriate threshold in FIG.

By setting

You can determine if the signal is coming into the sublobe by checking whether it has a larger or smaller value.

)가 주엽방향(미도시)에서 들어왔다고 판단될 경우 추정 입사각(

)과 관련된 측정값을 데이터 처리기(22)에 전송하게 된다. 이와 달리, 부엽방향(미도시)에서 들어왔다고 판단될 경우 입사각 추정값

과 관련된 측정값은 더 이상 처리하지 않게 된다.The incoming signal in FIG.

) Is estimated to come from the main leaf direction (not shown),

) Is transmitted to the data processor 22. On the other hand, when it is judged that it came from the side lobe direction (not shown), the incident angle estimate value

Measurements related to are no longer processed.

)를 기저대역 신호(

)로 컨버젼한다(단계 S300,S310). FIG. 2 is a flowchart for easily understanding an SLB process of the adaptive array radar shown in FIG. 1. Referring to FIG. 2, a signal flowing into the array antenna element 11 of FIG.

) Is the baseband signal (

(Step S300, S310).

)을 이용하여 동조 에너지(C)를 계산한다(단계 S320,S330).When the conversion is complete, an estimated incident angle is generated and the estimated incident angle and / or baseband signal (

), The tuning energy C is calculated (steps S320 and S330).

)를 이용하여 비동조 에너지(N)를 산출한다(단계 S331). At the same time, the baseband signal (

) Is used to calculate the untuned energy N (step S331).

)을 산출한다(단계 S340). 부연하면, 동조 에너지(C)를 비동조 에너지(N)로 나눈다.Using the calculated tuning energy (C) and non-tuning energy (N), the energy proportional value (

) Is calculated (step S340). In other words, the tuning energy (C) is divided by the non-tuning energy (N).

)이 문턱치(

)의 값보다 큰 지를 판단한다(단계 S350). Calculated energy proportional value (

) This threshold (

It is determined whether the value is greater than or equal to () (step S350).

)이 문턱치(

)의 값보다 크면 추정 입사각(

)이 주엽안에 있는 것으로 판단하고, 데이터 처리기(도 1의 22)에서 입력된 신호를 처리한다(단계 S350,S350-1). As a result of the determination in step S350, the calculated energy proportional value (

) This threshold (

Is greater than the estimated incident angle (

) Is determined to be in the main lobe, and the signal input from the data processor (22 in Fig. 1) is processed (steps S350 and S350-1).

)이 문턱치(

)의 값보다 작으면 상기 데이터 처리기(22)에서 추정 입사각(

)이 부엽안에 있는 것으로 판단하고 차단한다(단계 S361,S371).In contrast, as a result of the determination in step S350, the calculated energy proportional value (

) This threshold (

Less than a value of), the estimated angle of incidence (

) Is determined to be in the side lobe and blocked (steps S361, S371).

: 유입 신호

: 입사각

: 추정 입사각
11: 배열 안테나 소자
12: 기저 대역 신호
13: 입사각 추정부
14: 비동조 에너지 계산부
15: 동조 에너지 계산부
20: 전환 스위치
22: 데이터 처리기
C: 동조 에너지
N: 비동조 에너지
R: 에너지 비례값

: Incoming signal

: Angle of incidence

: Estimated incidence angle
11: array antenna elements
12: baseband signal
13: incident angle estimator
14: Untuned energy calculation unit
15: tuning energy calculation unit
20: toggle switch
22: data processor
C: tuning energy
N: non-tuned energy
R: energy proportional value

Claims (7)

delete delete delete delete delete A signal conversion step of converting the incoming signal introduced into the array antenna element into a baseband signal;
An estimated incidence angle calculation step of calculating an estimated incidence angle at which the incoming signal is incident on the converted baseband signal using a maximum likelihood algorithm;
Calculating a tuning energy using the converted baseband signal and the calculated estimated incidence angle;
An untuned energy calculation step of calculating untuned energy using the converted baseband signal;
Calculating an energy proportional value by dividing the tuning energy by untuned energy to calculate an energy proportional value;
Determining an energy proportional value magnitude that determines whether the energy proportional value is greater than a threshold value;
A signal processing step of processing the inflow signal that the estimated incidence angle is in the main lobe in the data processor if the threshold value is greater than the threshold value; And
As a result of the determination, if less than the value of the threshold signal blocking step of blocking the incoming signal by determining that the estimated incidence angle is in the side lobe;
The baseband signal is the following equation,

(here,

Is the incoming signal (

> 0),

ego,

ego,

Is the wavelength of the transmission frequency,

Is the distance between the array antenna elements,

Is the angle of incidence of the signal radiated and introduced into the array antenna element,

The

Is calculated by
The baseband signal is represented by a vector, the baseband signal vector is represented by the following equation,

Represented by the steering vector, the following equation,

Is indicated by
The baseband signal vector is

(here,

Indicates noise and includes both jammer and thermal noise).
The tuning energy is

(here,

Is the incident angle as the estimated incident angle

Represents an estimated incidence angle estimated by

The

As the inverse of,

H represents conjugate transpose,

Denotes the baseband signal vector),
The non-tuned energy is

SLB processing method of the adaptive array radar, characterized in that calculated by.
The method according to claim 6,
The energy proportional value is

SLB processing method of the adaptive array radar, characterized in that calculated by.

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