IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0992767
(2009-05-04)
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등록번호 |
US-8466834
(2013-06-18)
|
우선권정보 |
EP-08156238 (2008-05-15) |
국제출원번호 |
PCT/EP2009/055359
(2009-05-04)
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§371/§102 date |
20110214
(20110214)
|
국제공개번호 |
WO2009/138333
(2009-11-19)
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발명자
/ 주소 |
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출원인 / 주소 |
- The European Union, Represented by the European Commission
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
0 인용 특허 :
6 |
초록
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A method of radar-imaging a scene in the far-field of a one-dimensional radar array, comprises providing an array of backscatter data D(fm, x′n) of the scene, these backscatter data being associated to a plurality of positions x′n, n=0 . . . N−1, N1, that are regularly spaced along an axis of the ra
A method of radar-imaging a scene in the far-field of a one-dimensional radar array, comprises providing an array of backscatter data D(fm, x′n) of the scene, these backscatter data being associated to a plurality of positions x′n, n=0 . . . N−1, N1, that are regularly spaced along an axis of the radar array. The backscatter data for each radar array position x′n are sampled in frequency domain, at different frequencies fm, m=0 . . . M−1, M1, defined by fm=fc−B/2+m−Δf, where fc represents the center frequency, B the bandwidth and Δf the frequency step of the sampling. A radar reflectivity image 1 (αm′, βn′) is computed in a pseudo-polar coordinate system based upon the formula (2) with formula (3) where j represents the imaginary unit, formula (A) is the baseband frequency, FFT2D denotes the 2D Fast Fourier Transform operator, αm′, m′=0 . . . M−1, and βn′, n′=0 . . . N−1 represent a regular grid in the pseudo-polar coordinate system, and Pmax is chosen 0 depending on a predefined accuracy to be achieved. A corresponding method of radar-imaging a scene in the far-field of a two-dimensional radar array is also proposed. I(αm′,βn′)=∑p=0PmaxIp(αm′,βn′),Formula(2)I(αm′,βn′)=1p!-j2πβn′fcpFFT2DD(fm,xn′)(f^m,xn′)p,Formula(3)f^m=-B/2+m·ΔfFormula(A)
대표청구항
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1. Method of radar-imaging a scene in a far-field of a one-dimensional radar array, comprising providing an array of backscatter data of said scene, said backscatter data being herein denoted by D(fm, x′n), said backscatter data being associated to a plurality of radar array positions, herein denote
1. Method of radar-imaging a scene in a far-field of a one-dimensional radar array, comprising providing an array of backscatter data of said scene, said backscatter data being herein denoted by D(fm, x′n), said backscatter data being associated to a plurality of radar array positions, herein denoted by x′n, n=0 . . . N−1, N>1, regularly spaced along an axis of said radar array;the backscatter data being sampled, for each radar array position x′n, at different frequencies, herein denoted by fm, m=0 . . . M−1, M>1, defined by fm=fc−B/2+m·Δf, where fc represents a center frequency, B a bandwidth and Δf a frequency step;computing a radar reflectivity image, herein denoted by I(αm′, βn′), in a pseudo-polar coordinate system, in which coordinates of a point of said scene are expressible by equations: α=2ρcβ=2xλcρwhere α and β denote coordinates of said point in said pseudo-polar coordinate system;ρ denotes a range distance from a center of the radar array to said point,x denotes a coordinate, with respect to said axis, of an orthogonal projection of said point onto said one-dimensional radar array,c denotes speed of light, andλc a centre wavelength,said computing of said radar reflectivity image being effected on the basis of the following formula: I(αm′,βn′)=∑p=0PmaxIp(αm′,βn′),withIp(αm′,βn′)=1p![-j2πβn′fc]pFFT2D[D(fm,xn′)(f^mxn′)p],where j represents an imaginary unit,{circumflex over (f)}m=−B/2+m·Δf,FFT2D denotes a 2D Fast Fourier Transform operator,αm′, m′=0 . . . M−1, and βn′, n′=0. . . N−1 represent a regular grid in said pseudo-polar coordinate system,and Pmaxis chosen ≧0 depending on an accuracy to be achieved;wherein said providing an array of backscatter data of said scene and said computing a radar reflectivity image are carried out by an electronic computer processor device. 2. The method as claimed in claim 1, wherein said radar array positions are defined by x′n=−Lx/2+n·Δx′, where Lx represents a length of the radar array and Δx′ a spacing between said radar array positions. 3. The method as claimed in claim 1, wherein Pmax is chosen depending on a ratio of radar array length to range resolution. 4. The method as claimed in claim 1, wherein said radar reflectivity image in said pseudo-polar coordinate system is mapped into at least one of a polar coordinate system and a Cartesian coordinate system. 5. The method as claimed in claim 1, wherein at least one of a coherence image and a 2D-phase interferogram is computed based upon said radar reflectivity image in said pseudo-polar coordinate system. 6. The method as claimed in claim 5, wherein said at least one of a coherence image and a 2D-phase interferogram is mapped into at least one of a polar coordinate system and a Cartesian coordinate system. 7. Method of radar-imaging a scene in a far-field of a two-dimensional radar array, comprising providing an array of backscatter data of said scene, said backscatter data being herein denoted by D(fm, x′n, y′k), said backscatter data being associated to a plurality of radar array positions, herein denoted by (x′n, y′k) n=0 . . . N−1, N>1, k=0 . . . K−1, K>1, regularly spaced along a first and a second axis of said radar array;the backscatter data being sampled, for each radar array position (x′n,y′k) at different frequencies, herein denoted by fm, m=0 . . . M−1, M>1, defined by fm=fc−B/2+m·Δf, where fc represents a center frequency, B a bandwidth and Δf a frequency step;computing a radar reflectivity image, herein denoted by I(αm′, βn′, γk·), in a pseudo-spherical coordinate system, in which coordinates of a point of said scene are expressible by equations: α=2ρcβ=2xλcργ=2yλcρwhere α, β and γ denote coordinates of said point in said pseudo-spherical coordinate system;ρ denotes a range distance from a center of the radar array to said point,x denotes a coordinate, with respect to said first axis, of an orthogonal projection of said point onto said two-dimensional radar array,y denotes a coordinate, with respect to said second axis, of said orthogonal projection of said point onto said two-dimensional radar array,c denotes speed of light, andλc a centre wavelength,said computing of said radar reflectivity image being effected on the basis of the following formula: I(αm′,βn′,γk′)=∑p=0PmaxIp(αm′,βn′,γk′),withIp(αm′,βn′,γk′)=[-j2πfc]p∑q=0pβm′q,γk′p-qq!(p-q)!FFT3D[D(fm,xn′,yk′)f^mpxn′qyk′p-q],where j represents an imaginary unit,{circumflex over (f)}m=−B/2+m·Δf,FFT3D denotes a 3D Fast Fourier Transform operator,αm′, m′=0 . . . M−1, βn′, n′=0 . . . N−1 and γk′, k=0 . . . K−1, represent a regular grid in said pseudo-spherical coordinate system,and Pmax is chosen ≧0 depending on an accuracy to be achieved;wherein said providing an array of backscatter data of said scene and said computing a radar reflectivity image are carried out by an electronic computer processor device. 8. The method as claimed in claim 7, wherein said radar array positions are defined by x′n=−Lx/2+n·Δx′along said first axis, where Lx represents a length of the radar array along said first axis and Δx′ a spacing between said radar array positions along said first axis, and by y′k=−Ly/2+k·Δy′ along said second axis, where Ly represents a length of the radar array along said second axis and Δy′ a spacing between said radar array positions along said second axis. 9. The method as claimed in claim 7, wherein Pmax is chosen depending on ratios of radar array lengths along said first and said second axis to range resolution. 10. The method as claimed in claim 7, wherein said radar reflectivity image in said pseudo-spherical coordinate system is mapped into at least one of a spherical coordinate system and a Cartesian coordinate system. 11. The method as claimed in claim 7, wherein at least one of a coherence image and a 3D-phase interferogram is computed based upon said radar reflectivity image in said pseudo-spherical coordinate system. 12. The method as claimed in claim 11, wherein said at least one of a coherence image and a 3D-phase interferogram is mapped into at least one of a spherical coordinate system and a Cartesian coordinate system. 13. The method as claimed in claim 1, wherein said reflectivity image is computed in or nearly in real time. 14. The method as claimed in claim 7, wherein said reflectivity image is computed in or nearly in real time. 15. A computer program product for controlling a data processing apparatus, the computer program product embodied in a non-transitory computer-readable medium and comprising instructions causing said data processing apparatus to carry out a method of radar-imaging a scene in a far-field of a one-dimensional radar array when executed on said data processing apparatus, said method comprising: providing an array of backscatter data of said scene, said backscatter data being herein denoted by D(fm, x′n), said backscatter data being associated to a plurality of radar array positions, herein denoted x′n, n=0 . . . N−1, N>1, regularly spaced along an axis of said radar array;the backscatter data being sampled for each radar array position x′nat different frequencies, herein denoted by fm, m=0 . . . M−1, M>1, defined by fm=fc−B/2+m·Δf, where fc represents a center frequency, B a bandwidth and Δf a frequency step;computing a radar reflectivity image, herein denoted by I(αm′, βn′), in a pseudo-polar coordinate system, in which coordinates of a point of said scene are expressible by equations: α=2ρc β=2xλcρwhere α and β denote coordinates of said point in said pseudo-polar coordinate system;ρ denotes a range distance from a center of the radar array to said point,x denotes a coordinate, with respect to said axis, of an orthogonal projection of said point onto said one-dimensional radar array,c denotes speed of light, andλc a centre wavelength,said computing of said radar reflectivity image being effected on the basis of the following formula: I(αm′,βn′)=∑p=0PmaxIp(αm′,βn′),withIp(αm′,βn′)=1p![-j2πβn′fc]pFFT2D[D(fm,xn′)(f^mxn′)p],where j represents an imaginary unit,{circumflex over (f)}m=−B/2+m·Δf,FFT2D denotes a 2D Fast Fourier Transform operator,αm′, m′=0 . . . M−1, and βn′, n′=0 . . . N−1 represent a regular grid in said pseudo-polar coordinate system,and Pmax is chosen ≧0 depending on an accuracy to be achieved;wherein said providing an array of backscatter data of said scene and said computing a radar reflectivity image are carried out by an electronic computer processor device. 16. A computer program product for controlling a data processing apparatus, the computer program product embodied in a non-transitory computer-readable medium and comprising instructions causing said data processing apparatus to carry out a method of radar-imaging a scene in a far-field of a two-dimensional radar array when executed on said data processing apparatus, said method comprising: providing an array of backscatter data of said scene said backscatter data being herein denoted by D(fm, x′n, y′k), said backscatter data being associated to a plurality of radar array positions, herein denoted by (x′n, y′k) n=0 . . . N−1N>1, k=0 . . . K−1K>1, regularly spaced along a first and a second axis of said radar array;the backscatter data being sampled, for each radar array position (x′n,y′k) at different frequencies, herein denoted by fm, m=0 . . . M−1, M>1, defined by fm=fc−B/2+m·Δf, where fc represents a center frequency, B a bandwidth and Δf a frequency step;computing a radar reflectivity image herein denoted by I(αm′, βn′, γk′), in a pseudo-spherical coordinate system, in which coordinates of a point of said scene are expressible by equations: α=2ρc β=2xλcρ γ=2yλcρwhere α, β and γ denote coordinates of said point in said pseudo-spherical coordinate system;ρ denotes a range distance from a center of the radar array to said point,x denotes a coordinate, with respect to said first axis, of an orthogonal projection of said point onto said two-dimensional radar array,y denotes a coordinate, with respect to said second axis, of said orthogonal projection of said point onto said two-dimensional radar array,c denotes speed of light, andλc a centre wavelength,said computing of said radar reflectivity image being effected on the basis of the following formula: I(αm′,βn′γk′)=∑p=0PmaxIp(αm′,βn′γk′),withIp(αm′,βn′γk′)=[-j2πfc]p∑q=0pβm′q,γk′p-qq!(p-q)!FFT3D[D(fm,xn′,yk′)f^mpxn′qyk′p-q],where j represents an imaginary unit,{circumflex over (f)}^m=−B/2+m·Δf,FFT3D denotes a 3D Fast Fourier Transform operator,αm′, m′=0 . . . M−1, βn′, n′=0 . . . N−1and γk′, k=0 . . . K−1, represent a regular grid in said pseudo-spherical coordinate system,and Pmax is chosen ≧0 depending on an accuracy to be achieved;wherein said providing an array of backscatter data of said scene and said computing a radar reflectivity image are carried out by an electronic computer processor device.
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