Synthetic aperture radar (SAR) signal simulation method for sea waves

An implantable the sea wave the SAR signal imitation method

technical field

[0001] The invention relates to synthetic aperture radar's the application field, synthetic aperture radar signal imitation method for special referring to a sea wave.

background technology

[0002] SAR (i.e. synthetic aperture radar) and obtaining the signal through multiple integrated time to position improve wherein space resolution, is the land static field, the relative position position and terrain features and sensor is welded with a satellite orbit; unilaterallyIs the sea field, dynamic fluctuating of sea with that of additional traction, wherein a imaging an imaging process. Therefore, the progression of sea wave the SAR signal imitation is a improve's separation to the whole imaging process, and a on with the vital salient is the sensor module, a selection parameter.

[0003] SAR the signal imitation is arranged on the field the model base; the SAR signal imitation process, which is consider the single mode, obtaining the simulation data by mechanism for the model and a relationship of single mode. Prior art the SAR signal imitation method for ocean emitting with of less sea wave is clamped; the model for SAR signal imitation process is distributed surface model (DS), and is not less acoustic effect of the eustatic of an, therefore to the sea wave SAR signal perform simulate's result insufficiently accurately, less than the main model for Doppler of effect eustatic of a speed is bunching model (VB), wherein according to is the movable object SAR image processing. The prior art sea wave SAR image type which is M4S and RM two type tool, the prime tasks of the two type tool of the analyzing storm of interactive to the sea surface roughness (i.e surface. the influence), and is not less acoustic effect of the eustatic of a effect on the surface, and SAR system certificate a filter without referring to.

[0004] The summary; the prior art the SAR signal imitation method and sea SAR of the tool sea wave, although the sea wave spectra and outlet of the is capable of the first backscattering, the small storm is sea wave SAR signal imitation layer, further lacks the acoustic a problems for SAR signal imitation with eustatic considering of a, a are arranged for large storm is the sea wave SAR signal imitation, therefore are arranged to be SAR system and providing comprehensive simulation data.

invention content

[0005] Optical of the considering, the head of the present invention synthetic aperture radar signal imitation method for providing a sea wave, a SAR signal imitation method for solve prior art are arranged for large storm condition according, each lacks the eustatic considering to make the acoustic effect and the sea wave SAR signal imitation problems.

[0006] for the upper device, the invention claims the SAR signal imitation method of sea wave, comprising the following steps:

[0007] SI: For ocean wave spectrum to the sea wave perform, type structure comprises the multiple of unit area three-dimensional sea surface,

[0008] S2: Computing each unit area of the scattered field, and according to the speed bunching model collected by the unit area of the distance of a cell the position to the reflecting, and according to the scattered field and reflecting generate sea scattering diagram of a slot;

[0009] S3: To the sea scattering diagram perform mass of the SAR signal imitation obtained SAR analogue signal, and the SAR image algorithm to the analogue signal SAR perform processing obtained simulating SAR image.

[0010] And preferably, wherein a step SI, wherein sea wave spectrum is a to form accumulate:

[0011] (W-SHAPED K) is (S) capable of P (θ, K)

[0012] W-SHAPED, (K) is a sea wave, spectrum

[0013] S (K) is a one-dimensional spectrum; the long wave area, (S) CAPABLE of the classical, spectrumThe shortwave, (S) UPON blocking gravity Sgc holder (4 )and S holder. (4 ), And a different wave; the number

[0014] Ρ (Θ, Κ) is arranged; function

[0015] The K is sea wave vector, a K module K is 2 π/Λ is a sea wave number, A the sea wave wavelength;

[0016] Θ and direct type: connecting

<img id="idf0001" file="CN102955152AD00051.tif" img-content="drawing" img-format="tif" />

[0018] , Kx is sea wave vector K of χ direction device, Ky is a sea wave vector K of the y direction device.

[0019] And is preferably, wherein the classical spectrum is a J0NSWAP spectrum.

[0020] And preferably, wherein a step SI, wherein two criteria sea surface model constructions to the three-dimensional sea surface; the specifcially is: The long wave communication circuit criterion's outline, wherein the SAR resolution ratio unit is thinner, and is greater than electromagnetic wave the plane of unit area is similar, generating random sea surface; Shortwave the small criterion's any is rough, and gravity holder or ripple's wave form approximate; The gravity holder or ripple's wave form lines; the plane of unit area with sea surface model.

[0021] And is preferably, wherein the long wave is a swell profile to synchronize the disposed in the time stochastic process, the parameter is a high head the wave, peak cycle and sea wave spectrum main direction and sea wave spectrum sample; A remote a point of the spectral generate a method for any sea is a stochastic noise filter, a specifcially is: First generating random plurality of matrix N, wherein real part and component baseboard uniformly distributed on the O to); And a combination long spectrum I (K to) and matrix N obtained variable Lptl:

[0022]

<img id="idf0002" file="CN102955152AD00052.tif" img-content="drawing" img-format="tif" />

[0023] The upper) perform Fourier transform, a layer of ζ is an adjusting (1 (r) is:

[0024] ζ t is 0 (r) is real (aF_1 (Lt is 0) (r))

[0025] , A the uniformization parameter, composed of current waves' of the reference surface, comprising a χ and position information and y two direction, and ( ) Is as a plurality of the part thereof.

[0026] And preferably, wherein a step S2, each unit area of the scattered field is a direct type: a

[0027]

<img id="idf0003" file="CN102955152AD00053.tif" img-content="drawing" img-format="tif" />

[0028] Fully, and is the incidence field, type fully and scattered field, IT is a unit of the central point distance flying of; k= |the k | =2 π/λ is electromagnetic wave number, k is the incidence electromagnetic wave vector, λ is an wavelength; Subscript H and V respectively arranged behalf of horizontal and vertical polarization part; Superscript) and s of meter non-inductive incident field and dispersion-type field; Matrix χ meter non-inductive backscattering coefficient, j is the baseboard.

[0029] And is preferably, wherein the matrix X is given of a direct type:

[0030] X-RAY is FD (Θ j, δ χ, δ y)

[0031] , 91 The radar incidence angle, 6 by£ And Sy is a device for area are provided with χ and base of the y of unit area; at

[0032] Polarization effect of each matrix F meter non-inductive radar backscattering the surface high-rising direction and electromagnetic parameter rely on the;

[0033] The scalar OF is as follows:

[0034] THE (Θ j, δ χ, δ y) is f Aexp (j2k P) dA

[0035] , K is incident electromagnetic wave vector, A is a device for area is injected (x, y) plane of unit area, and P is a unit of the central point on any position of vector to of unit area;

[0036] p is device x-x0) x + (y-y0) y + (z (x, y) is z0) z

[0037] ; The χ is α, ζ). Is a centre axes of unit area, FORMULA, J, the deficiency are the x, y, z direction unit vector.

[0038] ROUGH (x, y) is Ζ. + δ χ (χ is χ). + δ y (y-y (|) +Zs (x, y), Sy is a device for area along the position to χ and base length direction of unit area slope); zs (x, y and) to the stochastic process of short spectrum.

[0039] And preferably, wherein a step S2, collected by the unit of the surface and a speed bunching model along the movement a cell according to the distance is a reflecting specifcially of the position to is:

[0040] The head inclination adjusting according to the scattering of unit area close to the device of a perform position of range:

<img id="idf0004" file="CN102955152AD00061.tif" img-content="drawing" img-format="tif" />

[0042] , IT is the sensor is provided with a scattering unit area of the distance; the processor is a speed sensor;

[0043] According to the speed of movement of sea of unit area, the position of the X units of area and map to the coordinate

[0044] Xf is x -- processor (r, t)

[0045] And the scattering of unit area along the electromagnetic wave propagation direction is speed:

[0046]

<img id="idf0005" file="CN102955152AD00062.tif" img-content="drawing" img-format="tif" />

[0047] , ω is a sea wave frequency, WJK) is a long spectrum, a K is a sea wave vector;

l (fi, eQ) is in l + tan2 O1 sin2 θ 0, δ is tarT1 (tan θ jsin θ). , θ | is a radar incidence angle, Θ Q is a black direction and current emitting test vector K of the sea surface of the included angle; composed of behalf of the sea wave the horizontal direction level, comprising MM and position information and y two direction.

[0048] Compared with the prior art, this invention following beneficial effects: Each sea wave the SAR signal imitation method of this invention claims a less than the acoustic effect of the eustatic of an, such capable of a large storm is the sea wave SAR signal imitation, is arranged to be SAR system and providing comprehensive simulation data.

Brief composed fo the drawings

[0049] A graph) am the invention sea wave flow drawing leds of SAR signal imitation method.

[0050] Digital 2 is a SAR image coordinate system.

[0051] Digital 3 is a sea height chart according to the test information.

[0052] Digital 4 is a sea distance of the test for outputting to the device for area position of the speed fixedly connected to the reflecting graph.

[0053] Digital 5 is the surface of the distribution chart according to the test information.

[0054] Digital 6 is an analogue signal echo chart according to the test information.

[0055] Digital 7 is an analogue SAR image according to the test information.

[0056] Digital 8 is an analogue SAR image distribution density function diagram according to the test information.

[0057] Digital 9 is an analogue SAR image image spectrum according to the test information.

[0058] Digital 10 is a test in the input current wave spectrum.

[0059] Digital 11 is a test of the two input current wave spectrum is images.

[0060] Digital 12 is a sea height map contrast chart according to the two information.

[0061] Digital 13 is an analogue SAR image comparison chart according to the two information.

[0062] Digital 14 is an analogue SAR image image spectrum contrast chart according to the two information.

Specifcially a groove

[0063] To the invention claims a compromised of light figure's specifcially embodiment perform the detail.

[0064] A graph in), the invention the SAR signal imitation method for ocean emitting comprises the following steps:

[0065] SI: For ocean wave spectrum to the sea wave perform, type structure comprises the multiple of unit area three-dimensional sea surface,,

[0066] ), Sea wave spectrum

[0067] The sea wave is composed of sea wave spectrum perform, the current wave spectrum (W-SHAPED K) is usual to form accumulate:

[0068] (W-SHAPED K) IS (S) CAPABLE OF P (Θ, K)))

[0069] , (S) CAPABLE of the one-dimensional spectrum; the long wave area, (S) CAPABLE of using the device for classical spectra, for example J0NSWAP, spectrumThe shortwave, (S) UPON blocking gravity holder (Sge K) and S holder. (K), and a different wave; the number

[0070] Ρ (Θ, Κ) is arranged; function

[0071] The K is sea wave vector, a K module K is 2 π/Λ is a sea wave number, A the sea wave wavelength;

[0072] Θ and direct type: connecting

<img id="idf0006" file="CN102955152AD00071.tif" img-content="drawing" img-format="tif" />

[0074] , Kx is sea wave vector K the X direction part, Ky is a sea wave vector K of the y direction device.

[0075] 2nd, Wherein a layer of modelling

[0076] The sea height of the space and time change rendering is:

[0077]

<img id="idf0007" file="CN102955152AD00072.tif" img-content="drawing" img-format="tif" />

[0078] , Wl (K) is a long spectrum, a K is a sea wave vector; composed of behalf of the sea wave the horizontal direction level, comprising MM and position ί one of controlling whether the y two direction; ω is sea wave frequency, t is time.

[0079] The three-dimensional sea surface is two criteria sea surface constructions model, the specifcially is: The long wave communication circuit criterion's outline, which is lower than the SAR resolution ratio unit, and it is greater than electromagnetic wave the plane of unit area is similar, generating random sea surface; Shortwave the small criterion's any is rough, a space short spectrum (is a gravity holder or ripple's wave form negative); the gravity holder or ripple's wave form lines; the plane of unit area with sea surface model. The main base of the method structure three-dimensional sea surface of the typical SAR system resolution ratio and sea wave a wave comparing very small, and compared with the sea wave shortwave very in a large path.

[0080] The long wave is a swell profile to synchronize the disposed in the time stochastic process, the parameter is a high head the wave, peak cycle and sea wave spectrum main direction and sea wave spectrum sample. A remote a point of the spectral is disposed on the diameter of close to the layer is a stochastic noise filter, wherein method specifcially is: First generating random plurality of matrix N, wherein real part and component baseboard uniformly distributed on the O to), N matrix strength a three-dimensional the internal surface; fourAnd a combination long spectrum WJK to) and matrix N obtained variable Lt is

[0081]

<img id="idf0008" file="CN102955152AD00073.tif" img-content="drawing" img-format="tif" />

[0082] The type of (4) perform Fourier transform, a three-dimensional sea surface of unit area of the is:

[0083] ζ is an adjusting ο (r) is real (aF_1 (Lt is 0) (r) pipe (4)

[0084] , A the uniformization parameter, wherein value and Fourier transform algorithm, relatedcomposed of behalf of the sea wave the horizontal direction level, comprising X-RAY) and position information of the direction; real ( ) Is as a plurality of the part thereof.

[0085] 3rd, Sea wave speed modelling

[0086] The composed of three-dimensional sea surface of unit area along the speed according to the distance is:

[0087]

<img id="idf0009" file="CN102955152AD00081.tif" img-content="drawing" img-format="tif" />

[0088] , ω is a sea wave frequency, WJK) is a long spectrum, a K is a sea wave vector;

l (fi, eQ) is + small tan2 θτ sin2 θ 0, δ is tarT1 (tan θ jsin θ Q), θ j is a radar incidence angle, Θ Q is a black direction and current emitting test vector K of the sea surface of the included angle; composed of behalf of the sea wave the horizontal direction level, comprising MM and position information and y two direction.

[0089] S2: The computing consists of three-dimensional sea surface of each unit of the scattered field, and according to the speed bunching model collected by the unit area of the distance of a cell the position to the reflecting, and according to the scattered field and reflecting generate sea scattering diagram of a slot;

[0090] The scattering computing unit of the needed to consider the whole of unit area a direction and device of unit area the influence of the short spectrum, by a spectrum I (K) made sea outline, full sea surface of the xy plane (i.e. the horizontal plane) are uniformly distributed, and a plurality of checking meter of the z a direction.

[0091] The single unit of the range of the direct type is:

[0092] z (x, y) is Z0+ δ χ (χ is χ 0) is + δ y (y-y0) +zs (x, y (7)

[0093] ; The X (l, y0, z0) is a centre axes of unit area; δ χ and δ γ is of unit area along the position to χ and base of the y of unit area; atzs (x, y and) to the stochastic process of short spectrum.

[0094] ), The Bragg of the oblique and

[0095] Order to estimation backscattering coefficient graph, we claim consider of the interactive of incident electromagnetic wave and a surface, is the small incidence angle; the lens of consider to the; Is the medium incidence angle, dominant mechanism is a end of the Bragg reflection of the oblique, andIs the large incidence angle, obvious results of the shielding and; And; the limiting case minimum and is incidence angle, without the actual value is the sea SAR system.

[0096] Each unit of the scattered field can be connected Kirchhoff approximation (KA, Kirchhoff) negative calculation, the scattered field and event field a relationship terminal of a gauge needle is:

[0097]

<img id="idf0010" file="CN102955152AD00082.tif" img-content="drawing" img-format="tif" />

[0098] Fully, and; £Is the incidence field, type fully and scattered field, IT is a unit of the central point distance flying of; k= |the k | =2 3 ΐ/λ is electromagnetic wave number, k is the incidence electromagnetic wave vector, λ is an wavelength; Subscript H and V respectively arranged behalf of horizontal and vertical polarization part; Superscript) and s is incident field and dispersion-type field; j baseboard is unit; The matrix χ is backscattering coefficient, a given of a direct type:

[0099] X-RAY is FD (Θ j, δ χ, δ y (9)

[0100] , 91 The radar incidence angle, 6 by£ And Sy is a device for area are provided with χ and base of the y of unit area; at

[0101] Matrix is F radar backscattering polarization effect according, a layer of unit area (direction. i.e unit of the average surface) and an parameter rely on (i.e. dielectric constant); a

[0102] The scalar OF is as follows:

[0103] THE (Θ j, δ χ, δ y) is f Aexp (j2k P) dA (10)

[0104] Comprising represented sea surface of air flow field dispersion-type the contribution, k at the middle) is the incidence electromagnetic wave vector, A is a device for area is injected (x, y) plane of unit area, and P is of unit area of the second universal radius of vector to of unit area;

[0105]

<img id="idf0011" file="CN102955152AD00091.tif" img-content="drawing" img-format="tif" />

[0106] ; The xQ, yQ, zQ) is a centre axes of unit area, z (x, y) sees connecting the transformer (7), x, $ are χ, 1, ζ direction unit vector.

[0107] The computing DPp δχ, Sy), mainly based on the backscattering mainly composed of the electromagnetic field wavelength a small sea wave spectrum component ensurring. Each sea wave height the less than the wavelength; and invention (j2kzsC0S the Θ J perform progression decomposition eXp, and retains the first step, a: obtaining

[0108]

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[0109],

(oho)

<img id="idf0013" file="CN102955152AD00093.tif" img-content="drawing" img-format="tif" />

[0111] , λ is an wavelength, Sy is a device for area along the position to χ and base of the y of unit area, at Θ) is a radar incidence angle;

[0112] Further Zs ( ) Is the last contact of a eclipse Gaussian any variable, wherein the average is:

[0113] (jZs (Kx, Ky) j2j is A.W (Kx, Ky (14)

[0114] , &lt; &gt; Is statistical wave, and (W ) K2x +K2y 12) value to position of the ensurring according to I= is a short gravitational wave and gravity holder or the holder spectrum, A is a device for area projects to the horizontal plane regions.

[0115] 2nd, Bunching speed

[0116] The scattering computer, for determining unit of the position on image plate, introduced speed bunching model.

[0117] According to base synthetic aperture, synthetic aperture radar according to the azimuth acoustic frequency of target perform positionings. The target the distance of movement, a reference frequency generation differential. The invention, an image deflection for generating position and close to the corresponding position is device.

[0118] The head inclination adjusting according to the scattering of unit area close to the device of a processor (r, t) perform position of range:

[0119]

<img id="idf0014" file="CN102955152AD00094.tif" img-content="drawing" img-format="tif" />

[0120] , IT is the sensor is the distance of of unit area, the processor is a speed sensor.

[0121] According to sea unit of the speed of movement processor (r, t); the position and map for χ's scattering of unit area of the coordinate

[0122]

<img id="idf0015" file="CN102955152AD00095.tif" img-content="drawing" img-format="tif" />

[0123] , The sea unit of the speed of movement processor (r, t) sees the transformer (6).

[0124] According to the position:

[0125] ω 2 g is | K (17)

[0126] , G is a gravity acceleration;

[0127] Type (16) is conversion:

[0128]

<img id="idf0016" file="CN102955152AD00101.tif" img-content="drawing" img-format="tif" />

[0129] , Internal (invariable) and position part of neglected.

(ο)

<img id="idf0017" file="CN102955152AD00102.tif" img-content="drawing" img-format="tif" />

[0131] S3 and sea scattering diagram perform mass of the SAR signal imitation obtained SAR analogue signal, and the SAR image algorithm to the analogue signal SAR perform processing obtained simulating SAR image.

[0132] The scattering diagram of obtaining each of unit area, wherein a perform mass of SAR signal imitation obtained SAR analogue signal, which is a SAR image algorithm to the analogue signal SAR perform processing obtained simulating SAR image. Which is a novel the SAR processing technology testing object focusing technology to analogue SAR image perform feature extraction of the post-processing. The is a SAR signal simulator and simple SAR image analogue differential, is particularly for is the state.

[0133] Shown as a digital 2, SAR system in height H is Rcos Sampler, along the direction χ uniformly head. Surface of the substrate of unit area and short spectra and contacting according to the speed bunching to obtain tracing dispersion-type field. χ ') is position sensor.

[0134] Less of sea mass of the SAR signal is as follows:

[0135]

<img id="idf0018" file="CN102955152AD00103.tif" img-content="drawing" img-format="tif" />

[0136]

[0137]

[0138] ω is ω (ξ, η) is the beam position of long, waveξ is Κχ, η is Ky/sin θ ±, θ ± is a radar incidence angle') Is dmId^ A/D ξ is ξίί, η is η &lt; ί, ω. η is doiIdrI A/D ξ is ξ 0, η is η 0, wavelength, ξ O and n are Curved the any of the long, spectrumFurther Oci is a corresponding angle frequency. Y (x, r, x/is O) is the X') is O scattering diagram of speed bunching head inclination adjusting; protective (x' is χ, r' is composed of; r) is made of field device, functionSAR s0 signal to an ( First according to Fourier transformation method, and s terminal ( ) For by an.

[0139] And obtaining the analogue signal SAR, which is an SAR image processing method, obtaining the analogue SAR image.

[0140] For analyzing ocean waves' SAR signal imitation method signal to the invention claims, comprising the distribution statistical and image spectrum analysis method for ocean emitting SAR signal imitation method to perform the invention the test, the image secondary 1024 is an.

[0141] The main sees parameter gauge):

[0142]) Meter

[0143]

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<img id="idf0020" file="CN102955152AD00111.tif" img-content="drawing" img-format="tif" />

[0146] Analogue for different wave and a on imaging; the loudspeaker is high facing the Semiconductor wave, the m wave high and Sm the wave high is perform the analogue; the movable Semiconductor wave High as a whole perform simulating process rendering.

[0147]The testing:

[0148] The result perform analyses facing the signal process, and verification the whole simulating process. First is arranged with the input function, and value of the meter the is parameter of the signal process with an, and is meaning.

[0149] The input current wave spectrum is a Jonswap spectrum head, a wave high is long, the peak period of 10s, a frequency spectrum peak and radar direction flight included angle, the connecting function is cos-2s type; the s parameter and 150; For a 2000X2000 sea height information, a resolution ratio of the shaping grid of the position to for). the invention grid according 4m, that is close to 1.9m. Obtaining the sea height information sees 3 digital.

[0150] And output with for each of unit area along the distance of unit area position of the speed and close to the reflecting, to 4 digital.

[0151] The packaging device for the transformer (12) and (13), the parameter is 10 m high speed wind, the value of 8m/s. According to the speed bunching a less with sea surface a to the scattering unit area of the influence, obtaining the sea scattering diagram to see 5 digital.

[0152] Obtaining the analogue SAR signal is the digital 6.

[0153] The perform imaging obtaining the analogue SAR image to see 7 digital.

[0154] The analogue line SAR image distribution of probability density is perform analysis. With the Rayleigh distribution and Lognormal), the Weibull distribution and Ga_a distribution perform parameter of. Sees 8 digital. The KS is KS detecting coefficient, and other is the distributed parameter.

[0155] Digital sees to simulation picture's spectrum 9 computer.

[0156] Sees digital with it correspondence's sea height 10 spectrum.

[0157] Can see of the result; the sea wave head wave and are low condition, relationship between sea wave and image is the linear relationship.

[0158]Testing two:

[0159] The simulating a perform Semiconductor wave head and is; a side facing m and rough seas high is Sm the perform the simulation. Of providing scattering diagram and analogue SAR image and sea wave spectrum perform contrast terminal.

[0160] First is the input information, an sea wave spectrum is a Jonswap spectra, sees 11 digital.

[0161] Analogue sea wave height map sees 12 digital.

[0162] The analogue SAR image for perform for simulating sees 13 digital.

[0163] The analyzing an image spectrum sees 14 digital.

[0164] To different head wave height of checking simulation result speed bunching effect's effect of sea SAR image. The result, and small wave with that SAR image non-linear a high.

[0165] The invention claims a based on a speed bunching effect SAR signal imitation method of sea wave, wherein the input current wave spectrum information and sensor information, the perform three-dimensional sea surface simulating, the rolling Bragg scattering and speed bunching effect's head inclination adjusting to the device, areaSAR signal imitation for use the mass motor, and imaging perform obtaining the sea simulating SAR image. To long, m head and wave high perform analysis Sm, the obtained simulation and an abnormal condition, a confirmed speed bunching effect's a terminal and imaging result.

[0166] Each sea wave the SAR signal imitation method of this invention claims a less than the acoustic effect of the eustatic of an, such capable of a large storm is the sea wave SAR signal imitation, is arranged to be SAR system and providing comprehensive simulation data.

[0167] The upper embodiment is a cast embodiment of invention, are used for limiting the invention, the invention's protection range of protecting is defined by use of ion beam. The technical field of the essential and protection range of protecting of the present invention, so the device for revisings to the invention or equate alternative, wherein the revising or equates alternative further provided with a vision and a on the invention protection range of protecting.