WO2017007095A1 - Method for calculating effective velocity for synthetic aperture radar (sar) signal processing - Google Patents

Method for calculating effective velocity for synthetic aperture radar (sar) signal processing Download PDF

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WO2017007095A1
WO2017007095A1 PCT/KR2015/014388 KR2015014388W WO2017007095A1 WO 2017007095 A1 WO2017007095 A1 WO 2017007095A1 KR 2015014388 W KR2015014388 W KR 2015014388W WO 2017007095 A1 WO2017007095 A1 WO 2017007095A1
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equation
signal processing
calculating
satellite image
radar signal
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French (fr)
Korean (ko)
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김동현
임병균
윤재철
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한국항공우주연구원
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9004—SAR image acquisition techniques
    • G01S13/9019—Auto-focussing of the SAR signals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques

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  • the present invention relates to a method for calculating an effective speed for satellite image radar signal processing. More specifically, the equation for the Pythagorean theorem range of the distance between two fuselages is transformed into a partial derivative with respect to azimuth time. In addition, the present invention relates to a method of calculating an effective velocity for satellite image radar signal processing that can obtain an effective velocity with a small amount of calculation by applying a method of establishing and solving simultaneous equations for two different observation times with a modified equation.
  • a SAR (Synthetic Aperture Radar) system is composed of Payload Hardware that directly performs observation of an object and SAR Processing Software that images acquired data through a synthesis process.
  • SAR signal processing through software compensates the phase history of raw data formed by hardware parameters and geometric distance information between sensor and object using various algorithms.
  • the key parameters it uses are Effective Velocity and Closed Approach.
  • V s Platform Speed
  • V g Ground Beam Speed
  • Such an approximate effect rate calculation method has a problem in that it is impossible to obtain a clear and correct high resolution SAR image.
  • the present invention transforms the equation for the range of Pythagorean theorem into a partial differential equation for azimuth time, and solves by solving simultaneous equations for two different observation times. It is an object of the present invention to provide a method for calculating an effective velocity for satellite image radar signal processing that can obtain an effective velocity with a small amount of calculation by applying a method.
  • an effect velocity calculation method for satellite image radar signal processing comprises the steps of: (a) establishing a Pythagorean theorem for calculating a range using an effective velocity; (b) converting the Pythagorean theorem into partial differential equations to partial differential equations; (c) substituting arbitrary bearing times ta1 and ta2 into the partial differential equations to establish equations for the bearing times ta1 and ta2, respectively; (d) establishing an effect rate (V e ) equation by combining two equations for ta1 and ta2; (e) calculating ⁇ R ⁇ which is a parameter of the effect velocity V e equation; And (f) calculating the effect velocity by substituting the parameter 'R' into the effect velocity equation (V e ).
  • the effect velocity calculation method for satellite image radar signal processing according to the present invention is transformed into a partial differential equation for azimuth time in order to calculate the effective velocity. Since we apply the method of setting and solving simultaneous equations for two different observation times, we can find the effective velocity very accurately with a small amount of computation.
  • FIG. 1 is a diagram of a geometric model between a target and a platform for explaining a method for calculating an effect speed for processing satellite image radar signals according to the present invention
  • FIG. 2 is a flowchart according to a method of calculating an effect speed for satellite image radar signal processing
  • Figure 3 is a comparison diagram of the target when focusing with a V e calculated according to the focusing target with the present invention when using a V e calculated in a conventional manner.
  • FIG. 1 is a diagram of a geometric model between a target and a platform for explaining a method for calculating an effect speed for satellite image radar signal processing according to the present invention.
  • the satellite image radar moves from one point to two point trajectories, and the satellite image radar observes a target while moving the trajectory.
  • ta1 and ta2 are any different azimuth time within the time while observing the target.
  • the target on the ground is already set through the beam pointing, the position of the target is always known.
  • the position of the platform can be known at any time ta.
  • FIG. 2 is a flowchart illustrating a method of calculating an effect speed for satellite image radar signal processing.
  • a step of establishing a Pythagorean theorem for calculating a range using an effective velocity is performed (S100).
  • Equation for the azimuth time ta1 and ta2 is the same as [Equation 4] and [Equation 5] below.
  • Equation 6 The effect rate calculation formula established through the step S400 is shown in Equation 6 below.
  • the parameter ⁇ R ⁇ is preferably calculated by expanding the polynomial as shown in Equation 7 below using the position, velocity, and acceleration information.
  • R (ta2) and R (ta1) are directly obtained from the geometric model, and R (ta2 ') and R (ta1') are also short time. It is simply obtained by the amount of change during.
  • step S600 the value of the effective speed (V e) the Doppler time (zeo Doppler azimuth time) and the outermost accessible (closest approach) of the relevant parameter in accordance with calculation zero As can be calculated using the above Equation (2).
  • the Doppler azimuth time may be calculated by substituting the bearing times ta1 and ta2 into Equation 2, subtracting and developing the equations for the bearing times ta1 and ta2.
  • Equation 12 Since V e and ta0 are calculated through Equation 6 and Equation 11, when one of Equation 2 is used for an arbitrary time point, the closest distance R 0 is expressed as Equation 12] can be calculated immediately.
  • Equation 12 ta3 is used at an arbitrary time point, but it is preferable to set it as a time point midway between ta1 and ta2 in FIG.
  • FIG. 3 is a diagram comparing the case where the target focus V e calculated according to the focusing target with the present invention when using a V e calculated in a conventional manner.
  • V s (satellite) speed
  • V g (satellite) surface velocity

Abstract

A method for calculating effective velocity for synthetic aperture radar (SAR) signal processing according to the present invention comprises the steps of: (a) establishing the Pythagorean theorem equation for calculating a range using effective velocity; (b) partially differentiating the Pythagorean theorem equation so as to transform the same into a partial differential equation; (c) substituting arbitrary azimuth times ta1 and ta2 into the partial differential equation so as to establish equations for the azimuth times ta1 and ta2 respectively; (d) solving simultaneous equations consisting of the two equations for ta1 and ta2 so as to establish an equation with respect to effective velocity (Ve); (e) calculating "R" which is a parameter of the effective velocity equation (Ve); and (f) calculating the effective velocity by substituting the parameter "R" into the effective velocity equation (Ve). Accordingly, the present invention can obtain a very accurate effective velocity with a small amount of calculation.

Description

위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법Method of Calculating Effect Speed for Satellite Image Radar Signal Processing
본 발명은 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법에 관한 것으로서, 더욱 상세하게는 두 동체 간의 거리의 변화를 피타고라스의 정리 형태의 range에 대한 식을 azimuth time에 대해서 편미분한 형태의 식으로 변형하고, 변형된 식으로 서로 다른 두 관측 시간에 대한 연립 방정식을 세워서 푸는 방식을 적용함으로써 작은 계산량으로, 매우 정확하게 effective velocity를 획득할 수 있는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법에 관한 것이다.The present invention relates to a method for calculating an effective speed for satellite image radar signal processing. More specifically, the equation for the Pythagorean theorem range of the distance between two fuselages is transformed into a partial derivative with respect to azimuth time. In addition, the present invention relates to a method of calculating an effective velocity for satellite image radar signal processing that can obtain an effective velocity with a small amount of calculation by applying a method of establishing and solving simultaneous equations for two different observation times with a modified equation.
일반적으로, SAR (Synthetic Aperture Radar) 시스템은 물체에 대한 관측을 직접 수행하는 Payload Hardware와 획득한 데이터를 합성 과정을 통해서 영상화하는 SAR Processing Software로 이루어진다. In general, a SAR (Synthetic Aperture Radar) system is composed of Payload Hardware that directly performs observation of an object and SAR Processing Software that images acquired data through a synthesis process.
소프트웨어를 통한 SAR 신호처리는 하드웨어 파라미터와 센서와 물체 간의 기하적인 거리 정보로 형성된 원시데이터의 Phase History를 여러 가지 알고리즘을 이용하여 보상한다. 이때, 어떠한 알고리즘이든지, 그것이 사용하는 핵심 파라미터에는 Effective Velocity와 Closest Approach가 있다.SAR signal processing through software compensates the phase history of raw data formed by hardware parameters and geometric distance information between sensor and object using various algorithms. In any algorithm, the key parameters it uses are Effective Velocity and Closed Approach.
종래의 SAR 관련 기술들에는 구체적인 계산 방법과 원리를 드러내 놓고 있지 않다. Conventional SAR-related techniques do not reveal specific calculation methods and principles.
수학식 1
Figure PCTKR2015014388-appb-M000001
 Equation 1
Figure PCTKR2015014388-appb-M000001
Vs: 플랫폼 속도 Vg:그라운드 빔 속도V s : Platform Speed V g : Ground Beam Speed
단지, 상기 [수학식 1]과 같은 상당한 근사화를 적용한 대략적인 효과속도(effective velocity) 계산 방법만을 제공하고 있다. It only provides an approximate effective velocity calculation method to which a significant approximation such as [Equation 1] is applied.
이와 같은 대략적인 효과속도 계산방법으로는 명확하고 올바른 고해상도 SAR 영상을 획득할 수 없다는 문제점이 있다. Such an approximate effect rate calculation method has a problem in that it is impossible to obtain a clear and correct high resolution SAR image.
(선행기술문헌)(Prior art document)
(특허문헌)(Patent literature)
대한민국 등록특허공보 제10-1315243호(2013. 09. 30)Republic of Korea Patent Publication No. 10-1315243 (2013. 09. 30)
상술한 문제점을 극복하기 위하여, 본 발명은 피타고라스의 정리 형태의 range에 대한 식을 azimuth time에 대해서 편미분한 형태의 식으로 변형하고, 변형된 식으로 서로 다른 두 관측 시간에 대한 연립 방정식을 세워서 푸는 방식을 적용함으로써 작은 계산량으로, 매우 정확하게 effective velocity를 획득할 수 있는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법의 제공을 목적으로 한다.In order to overcome the above problems, the present invention transforms the equation for the range of Pythagorean theorem into a partial differential equation for azimuth time, and solves by solving simultaneous equations for two different observation times. It is an object of the present invention to provide a method for calculating an effective velocity for satellite image radar signal processing that can obtain an effective velocity with a small amount of calculation by applying a method.
상술한 목적을 달성하기 위한, 본 발명에 따른 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법은 (a) 효과속도(Effective Velocity)를 사용하여 Range를 계산하기 위한 피타고라스 정리 수식을 세우는 단계; (b) 상기 피타고라스 정리 수식을 편미분하여 편미분식으로 변경하는 단계; (c) 상기 편미분식에 임의의 방위시간 ta1과 ta2를 대입하여 상기 방위시간 ta1과 ta2에 대한 식을 각각 세우는 단계; (d) 상기 ta1과 ta2에 대한 두 식을 연립하여 효과속도(Ve) 방정식을 세우는 단계; (e) 상기 효과속도(Ve) 방정식의 파라미터인 `R`을 계산하는 단계; 및 (f) 상기 파라미터 `R`을 상기 효과속도 방정식(Ve)에 대입하여 효과속도를 계산하는 단계;를 포함하는 것을 특징으로 한다.In order to achieve the above object, an effect velocity calculation method for satellite image radar signal processing according to the present invention comprises the steps of: (a) establishing a Pythagorean theorem for calculating a range using an effective velocity; (b) converting the Pythagorean theorem into partial differential equations to partial differential equations; (c) substituting arbitrary bearing times ta1 and ta2 into the partial differential equations to establish equations for the bearing times ta1 and ta2, respectively; (d) establishing an effect rate (V e ) equation by combining two equations for ta1 and ta2; (e) calculating `R` which is a parameter of the effect velocity V e equation; And (f) calculating the effect velocity by substituting the parameter 'R' into the effect velocity equation (V e ).
본 발명에 따른 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법은 Effective velocity를 계산하기 위해서, 피타고라스의 정리 형태의 range에 대한 식을 azimuth time에 대해서 편미분한 형태의 식으로 변형하여, 이 형태의 식으로 서로 다른 두 관측 시간에 대한 연립 방정식을 세워서 푸는 방식을 적용하기 때문에, 작은 계산량으로, 매우 정확하게 effective velocity를 구할 수 있는 효과가 있다.In order to calculate the effective velocity, the effect velocity calculation method for satellite image radar signal processing according to the present invention is transformed into a partial differential equation for azimuth time in order to calculate the effective velocity. Since we apply the method of setting and solving simultaneous equations for two different observation times, we can find the effective velocity very accurately with a small amount of computation.
도 1은 본 발명에 따른 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법을 설명하기 하기 위한 타겟과 플랫폼 간의 기하모델 도면,1 is a diagram of a geometric model between a target and a platform for explaining a method for calculating an effect speed for processing satellite image radar signals according to the present invention;
도 2는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법에 따른 흐름도, 및 2 is a flowchart according to a method of calculating an effect speed for satellite image radar signal processing;
도 3은 종래 방식으로 계산된 Ve를 이용한 경우 타겟 포커싱과, 본 발명에 따라 계산된 Ve를 이용한 경우 타겟 포커싱의 비교도면이다.Figure 3 is a comparison diagram of the target when focusing with a V e calculated according to the focusing target with the present invention when using a V e calculated in a conventional manner.
이하, 첨부 도면을 참조하여 본 발명의 실시예를 보다 상세하게 설명하고자 한다. 이에 앞서, 본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정하여 해석되어서는 아니 되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여, 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다.Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the ordinary or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own inventions. Based on the principle that it can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.
따라서, 본 명세서에 기재된 실시예와 도면에 도시된 구성은 본 발명의 가장 바람직한 일 실시예에 불과할 뿐이고 본 발명의 기술적 사상을 모두 대변하는 것은 아니므로, 본 출원시점에 있어서 이들을 대체할 수 있는 다양한 균등물과 변형예들이 있을 수 있음을 이해하여야 한다.Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.
도 1은 본 발명에 따른 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법을 설명하기 하기 위한 타겟과 플랫폼 간의 기하모델 도면이다.1 is a diagram of a geometric model between a target and a platform for explaining a method for calculating an effect speed for satellite image radar signal processing according to the present invention.
도 1에서 위성용 영상 레이더는 1지점에서 2지점 궤적으로 이동하고, 상기 궤적을 이동하는 동안 상기 위성용 영상 레이더가 타겟(target)을 관측한다. In FIG. 1, the satellite image radar moves from one point to two point trajectories, and the satellite image radar observes a target while moving the trajectory.
한편, 도 1에서 ta1과 ta2는 상기 타겟(target)을 관측하는 동안의 시간 내에서 임의의 서로 다른 방위시간(azimuth time)이다.Meanwhile, in FIG. 1, ta1 and ta2 are any different azimuth time within the time while observing the target.
이때, 지상에 있는 상기 타겟은 이미 빔 포인팅을 통해 설정되어 있어, 상기 타겟의 위치는 항상 알고 있는 상황이다.At this time, the target on the ground is already set through the beam pointing, the position of the target is always known.
물론, 플랫폼(platform)의 상태 정보를 통해서, 임의의 시간 ta에서 상기 플랫폼의 위치는 알 수 있다.Of course, through the platform state information, the position of the platform can be known at any time ta.
상술한 바와 같이 용어를 정의하고, 조건을 전제한 후 도 2를 참조하여, 본 발명에 따른 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법에 대하여 설명한다.After the terms are defined and the conditions are assumed as described above, the method of calculating the effect speed for satellite image radar signal processing according to the present invention will be described with reference to FIG. 2.
참고로, 도 2는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법에 따른 흐름도이다.For reference, FIG. 2 is a flowchart illustrating a method of calculating an effect speed for satellite image radar signal processing.
먼저, 효과속도(Effective Velocity)를 사용하여 Range를 계산하기 위한 피타고라스 정리 수식을 세우는 단계를 수행한다(S100).First, a step of establishing a Pythagorean theorem for calculating a range using an effective velocity is performed (S100).
수학식 2
Figure PCTKR2015014388-appb-M000002
 Equation 2
Figure PCTKR2015014388-appb-M000002
R : 경사거리R: Inclined Distance
R0 : 최접근거리R 0 : Closest Range
ta0 : 최근접시간ta0: Nearest time
이후, 상기 [수학식 2]를 시간변수 ta에 대하여 편미분한 후, 식을 정리하여 편미분한 아래의 [수학식 3]의 형태로 변형하는 단계를 수행한다(S200).Subsequently, after the partial expression of [Equation 2] with respect to the time variable ta, the step of modifying the equation into the form of [Equation 3] below the partial differential operation is performed (S200).
수학식 3
Figure PCTKR2015014388-appb-M000003
 Equation 3
Figure PCTKR2015014388-appb-M000003
상기 방위시간 ta1과 ta2를 각각 상기 [수학식 3]에 대입하여 상기 방위시간 ta1과 ta2에 대한 식을 각각 세우는 단계를 수행한다(S300)Substituting the azimuth time ta1 and ta2 into [Equation 3], respectively, establishes an equation for the azimuth time ta1 and ta2, respectively (S300).
상기 방위시간 ta1과 ta2에 대한 식은 아래의 [수학식 4]와 [수학식 5]와 같다.Equation for the azimuth time ta1 and ta2 is the same as [Equation 4] and [Equation 5] below.
수학식 4
Figure PCTKR2015014388-appb-M000004
 Equation 4
Figure PCTKR2015014388-appb-M000004
수학식 5 Equation 5
상기 [수학식 5]에서 상기 [수학식 4]를 빼, 두 식을 연립 방정식으로 효과속도(Ve) 방정식을 세우는 단계를 수행한다(S400). Subtracting the [Equation 4] from the [Equation 5], the step of establishing the effect velocity (V e ) equations as a system of simultaneous equations (S400).
상기 S400 단계를 통해 성립된 효과속도 계산식은 아래의 [수학식 6]과 같다.The effect rate calculation formula established through the step S400 is shown in Equation 6 below.
수학식 6
Figure PCTKR2015014388-appb-M000006
 Equation 6
Figure PCTKR2015014388-appb-M000006
Figure PCTKR2015014388-appb-I000001
Figure PCTKR2015014388-appb-I000001
이후, 측정데이터인 상기 타겟과 플래폼의 위치, 속도, 가속도를 이용하여 상기 효과속도 방정식의 유일한 파라미터인 `R`을 계산하는 단계를 수행한다(S500). Thereafter, a step of calculating `R` which is the only parameter of the effect velocity equation is performed using the position, velocity, and acceleration of the target and platform, which are measured data (S500).
이때, 상기 파라미터인 `R`은 상기 위치, 속도, 가속도 정보를 이용하여 아래의 [수학식 7]처럼 다항식으로 전개하여 계산되는 것이 바람직하다.At this time, the parameter `R` is preferably calculated by expanding the polynomial as shown in Equation 7 below using the position, velocity, and acceleration information.
수학식 7
Figure PCTKR2015014388-appb-M000007
 Equation 7
Figure PCTKR2015014388-appb-M000007
위에서 전제한 바와 같이, 타겟과 플랫폼의 위치는 이미 알고 있기 때문에 R(ta2), R(ta1)은 기하모델로 바로 구해지는 값이고, R(ta2'), R(ta1')도 역시 짧은 시간 동안의 변화량으로써 간단하게 구해진다.As assumed above, since the location of the target and platform is already known, R (ta2) and R (ta1) are directly obtained from the geometric model, and R (ta2 ') and R (ta1') are also short time. It is simply obtained by the amount of change during.
마지막 단계로서, 상기 `S500`단계에서 계산된 상기 파라미터 `R`을 상기 효과속도 계산식인 [수학식 6]에 대입하여 효과속도를 계산하는 단계를 수행한다(S600)As a final step, the step of calculating the effect speed by substituting the parameter 'R' calculated in the step 'S500' into the equation [Equation 6] (S600).
상술한 바와 같이 편미분을 이용함으로써 계산이 매우 정확해진다.As described above, the calculation of the partial derivative makes the calculation very accurate.
상기 S600 단계에서 상기 효과속도(Ve)가 계산됨에 따라 관련 파라미터인 제로 도플러 시간(zeo Doppler azimuth time)과 최접근(closest approach) 값은 상기 [수학식 2]를 이용하여 계산할 수 있다.In step S600 the value of the effective speed (V e) the Doppler time (zeo Doppler azimuth time) and the outermost accessible (closest approach) of the relevant parameter in accordance with calculation zero As can be calculated using the above Equation (2).
먼저, 도플러 시간(zeo Doppler azimuth time)은 상기 [수학식 2]에 상기 방위시간 ta1과 ta2를 대입하여, 상기 방위시간 ta1과 ta2에 대한 식을 세우고 서로 빼고 전개함으로 계산할 수 있다.First, the Doppler azimuth time may be calculated by substituting the bearing times ta1 and ta2 into Equation 2, subtracting and developing the equations for the bearing times ta1 and ta2.
즉, 상기 [수학식 2]에 상기 방위시간 ta1과 ta2를 대입하면, 상기 방위시간 ta1과 ta2에 대한 수식은 아래의 [수학식 8]과 [수학식 9]과 같다.That is, if the bearing times ta1 and ta2 are substituted into the above [Equation 2], the equations for the bearing times ta1 and ta2 are as shown in [Equation 8] and [Equation 9] below.
수학식 8
Figure PCTKR2015014388-appb-M000008
 Equation 8
Figure PCTKR2015014388-appb-M000008
수학식 9
Figure PCTKR2015014388-appb-M000009
 Equation 9
Figure PCTKR2015014388-appb-M000009
상기 [수학식 8]에서 [수학식 9]을 뺀 후, 전개 후 정리하면, 아래의 [수학식 10]와 같다.After subtracting [Equation 9] from the above [Equation 8], and rearranging after development, it is as shown in [Equation 10] below.
수학식 10
Figure PCTKR2015014388-appb-M000010
 Equation 10
Figure PCTKR2015014388-appb-M000010
Figure PCTKR2015014388-appb-I000002
Figure PCTKR2015014388-appb-I000002
이후, 상기 [수학식 10]의 전개된 수식에서 좌변의 ta0를 제외한 나머지 변수들을 우변으로 넘기면, 아래의 [수학식 11]과 같이 도플러 시간(zeo Doppler azimuth time)을 계산할 수 있다.Subsequently, when the remaining variables except for ta0 on the left side are passed to the right side in the developed equation of [Equation 10], a Doppler azimuth time may be calculated as shown in Equation 11 below.
수학식 11
Figure PCTKR2015014388-appb-M000011
 Equation 11
Figure PCTKR2015014388-appb-M000011
상기 [수학식 6]과 [수학식 11]을 통해 Ve와 ta0이 계산되었기 때문에 임의의 시점에 대하여 [수학식 2]의 하나의 이용하면 상기 최근접거리(R0) 값을 아래 [수학식 12]와 같이 바로 계산할 수 있다.Since V e and ta0 are calculated through Equation 6 and Equation 11, when one of Equation 2 is used for an arbitrary time point, the closest distance R 0 is expressed as Equation 12] can be calculated immediately.
수학식 12
Figure PCTKR2015014388-appb-M000012
 Equation 12
Figure PCTKR2015014388-appb-M000012
상기 [수학식 12]에서 ta3는 임의의 시점으로 사용하지만, 도 1에서 ta1과 ta2 사이의 중간 쯤의 시점으로 잡는 것이 바람직하다. In Equation 12, ta3 is used at an arbitrary time point, but it is preferable to set it as a time point midway between ta1 and ta2 in FIG.
상술한 바와 같이, 본 발명에 따른 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법으로 계산된 Ve를 이용한 경우, 도 3에 도시된 바와 같이, 타겟 포커싱이 훨씬 명확함을 알 수 있다.As described above, in the case of using V e calculated as the method for calculating the effect speed for satellite image radar signal processing according to the present invention, it can be seen that the target focusing is much clearer as shown in FIG. 3.
참고로, 도 3은 종래 방식으로 계산된 Ve를 이용한 경우 타겟 포커싱과, 본 발명에 따라 계산된 Ve를 이용한 경우 타겟 포커싱의 비교도면이다.For reference, FIG. 3 is a diagram comparing the case where the target focus V e calculated according to the focusing target with the present invention when using a V e calculated in a conventional manner.
이상과 같이, 본 발명은 비록 한정된 실시 예와 도면에 의해 설명되었으나, 본 발명은 이것에 의해 한정되지 않으며 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자에 의해 본 발명의 기술 사상과 하기에 기재될 청구범위의 균등 범위 내에서 다양한 수정 및 변형이 가능함은 물론이다.As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto, and the present invention is provided by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.
(부호의 설명)(Explanation of the sign)
Vs : (위성)속도 V s : (satellite) speed
Vg : (위성)지표면속도V g : (satellite) surface velocity
Ve : 효과속도V e : Effect Speed
R : 경사거리R: Inclined Distance
R0 : 최근접거리R 0 : nearest distance
ta0 : 최근접시간ta0: Nearest time

Claims (8)

  1. (a) 효과속도(Effective Velocity)를 사용하여 Range를 계산하기 위한 피타고라스 정리 수식을 세우는 단계;(a) formulating a Pythagorean theorem for calculating a range using an effective velocity;
    (b) 상기 피타고라스 정리 수식을 편미분하여 편미분식으로 변경하는 단계;(b) converting the Pythagorean theorem into partial differential equations to partial differential equations;
    (c) 상기 편미분식에 임의의 방위시간 ta1과 ta2를 대입하여 상기 방위시간 ta1과 ta2에 대한 식을 각각 세우는 단계; (c) substituting arbitrary bearing times ta1 and ta2 into the partial differential equations to establish equations for the bearing times ta1 and ta2, respectively;
    (d) 상기 ta1과 ta2에 대한 두 식을 연립하여 효과속도(Ve) 방정식을 세우는 단계;(d) establishing an effect rate (V e ) equation by combining two equations for ta1 and ta2;
    (e) 상기 효과속도(Ve) 방정식의 파라미터인 `R`을 계산하는 단계; 및(e) calculating `R` which is a parameter of the effect velocity V e equation; And
    (f) 상기 파라미터 `R`을 상기 효과속도 방정식(Ve)에 대입하여 효과속도를 계산하는 단계;를 포함하는 것을 특징으로 하는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법. and calculating the effect speed by substituting the parameter 'R' into the effect speed equation (V e ) for the satellite image radar signal processing.
  2. 제 1항에 있어서, The method of claim 1,
    상기 (a)단계의 상기 피타고라스 정리 수식은 The Pythagorean theorem of step (a) is
    Figure PCTKR2015014388-appb-I000003
    Figure PCTKR2015014388-appb-I000003
    R : 경사거리R: Inclined Distance
    R0 : 최근접거리R 0 : nearest distance
    ta0 : 최근접시간ta0: Nearest time
    인 것을 특징으로 하는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법.Effect speed calculation method for satellite image radar signal processing, characterized in that.
  3. 제 1항에 있어서, The method of claim 1,
    상기 (b)단계의 상기 편미분식은 The partial differential equation of step (b) is
    Figure PCTKR2015014388-appb-I000004
    인 것을 특징으로 하는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법.
    Figure PCTKR2015014388-appb-I000004
    Effect speed calculation method for satellite image radar signal processing, characterized in that.
  4. 제 1항에 있어서, The method of claim 1,
    상기 (c)단계에서 상기 방위시간 ta1과 ta2에 대한 식은 각각In the step (c), the expressions for the azimuth times ta1 and ta2 are respectively
    Figure PCTKR2015014388-appb-I000005
    Figure PCTKR2015014388-appb-I000005
    Figure PCTKR2015014388-appb-I000006
    인 것을 특징으로 하는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법.
    Figure PCTKR2015014388-appb-I000006
    Effect speed calculation method for satellite image radar signal processing, characterized in that.
  5. 제 1항에 있어서, The method of claim 1,
    상기 (d)단계에서 세워진 상기 효과속도(Ve) 방정식은 The effect velocity (V e ) equation established in step (d) is
    Figure PCTKR2015014388-appb-I000007
    인 것을 특징으로 하는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법.
    Figure PCTKR2015014388-appb-I000007
    Effect speed calculation method for satellite image radar signal processing, characterized in that.
  6. 제 1항에 있어서,The method of claim 1,
    상기 (e)단계의 상기 파라미터인 `R`은 The parameter 'R' in the step (e) is
    Figure PCTKR2015014388-appb-I000008
    로 계산되는 것을 특징으로 하는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법.
    Figure PCTKR2015014388-appb-I000008
    Effect speed calculation method for satellite image radar signal processing, characterized in that calculated by.
  7. 제 2항에 있어서, The method of claim 2,
    상기 제로 도플러 시간(zeo Doppler azimuth time)은The zero Doppler azimuth time is
    상기 피타고라스 정리 수식에 상기 방위시간 ta1과 ta2를 대입하고, 상기 방위시간 ta1과 ta2에 대한 수식을 연립하고, 상기 (d)단계에서 계산된 상기 효과속도(Ve)를 대입하여 Substituting the azimuth time ta1 and ta2 into the Pythagorean theorem, the equations for the azimuth time ta1 and ta2 are coalesced, and substituting the effective speed (V e ) calculated in step (d)
    Figure PCTKR2015014388-appb-I000009
    의 식으로 계산하는 것을 특징으로 하는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법.
    Figure PCTKR2015014388-appb-I000009
    An effective speed calculation method for satellite image radar signal processing, characterized by the following equation.
  8. 제 7항에 있어서,The method of claim 7, wherein
    임의의 시점에 대한 상기 최근접거리(closest approach) 값은 상기 피타고라스 정리 수식에 대입하여
    Figure PCTKR2015014388-appb-I000010
    으로 계산하는 것을 특징으로 하는 위성용 영상레이더 신호처리를 위한 효과 속도 계산 방법.    The closest approach value for any point in time is substituted for the Pythagorean theorem.
    Figure PCTKR2015014388-appb-I000010
    Effect speed calculation method for satellite image radar signal processing, characterized in that for calculating.
PCT/KR2015/014388 2015-07-06 2015-12-29 Method for calculating effective velocity for synthetic aperture radar (sar) signal processing WO2017007095A1 (en)

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