CN104280735B - MIMO-SAR formation method based on arcuate array antenna and device - Google Patents

Abstract

The invention discloses a kind of MIMO SAR formation method based on arcuate array antenna and device.The method includes: sample the echo-signal received via arcuate array antenna, and wherein, this echo-signal is that the microwave signal launched by arcuate array antenna reflects to form through observation scene；According to sampling angle interval, received echo-signal is arranged, obtain arcuate array imaging data；Arcuate array imaging data is carried out distance to inverse Fourier transform, obtain signal after Range compress；Signal after compressing of adjusting the distance carries out tiltedly and Residual video phase compensates；To through go tiltedly and Residual video phase compensate after the signal that obtains carry out distance to Fourier transformation, obtain distance wave-number domain signal；Wave-number domain signal of adjusting the distance is filtered and coherent superposition imaging processing, obtains image pixel value；And generate image based on image pixel value.Thereby, it is possible to expand microwave imaging regional extent and arcuate array aerial signal can be carried out effective imaging processing.

Description

MIMO-SAR formation method based on arcuate array antenna and device

Technical field

The present invention relates to microwave imaging field, in particular it relates to a kind of based on arcuate array antenna MIMO-SAR (multiple-input and multiple-output-synthetic aperture radar) formation method and device.

Background technology

Traditional visual, optics or the measure such as infrared by landform, weather and round the clock etc. factor affected relatively Greatly, do not possesses round-the-clock and round-the-clock ability to work.Airborne array antenna forword-looking imaging system can not only Enough penetrate cigarette, mist, cloud layer and floating dust etc., and not by weather and climatic effect, and can be to aircraft Region, front lower place carries out Real-time High Resolution rate imaging, moreover it is possible to for aircraft landing, scout, search and rescue and take off Real terrestrial information is provided, strengthens navigation and the transport rescue ability of aircraft.

Existing airborne array antenna forword-looking imaging system is based on airborne linear array antenna forword-looking imaging machine System, utilizes microwave switch switching to realize linear array synthesis, carries out region, aircraft flight route front lower place High-resolution imaging.But owing to using linear array antenna and time sharing mode so that it is there is more problem Need to improve further.On the one hand, its areas imaging is primarily limited to the beam area of individual antenna, i.e. The observation of big field range can not be realized.Thus, if aircraft wants to observe region about, it needs to move Move to this areas adjacent, and use airborne linear array antenna to carry out microwave imaging perception.If aircraft exists The environment that mountain area etc. are complex such as fly, by restriction of obstacle, it may not be possible to frequently move, and And move dangerous property.In that way it is possible to just desired zone cannot be carried out microwave imaging perception.Another Aspect, in linear array antenna, array increases along with beam area to resolution and reduces, Ye Jifen Resolution changes with Target space position.Therefore, the high-resolution imaging observation being unfavorable for around airborne platform.

Additionally, due to the pore size versions of arcuate array MIMO-SAR is arc, conventional with ground level work For the BPA (Back Projection Algorithm, back-projection algorithm are called for short BPA) with reference to platform Processing accuracy be restricted, it is impossible to directly its echo-signal is carried out imaging processing.

Summary of the invention

It is an object of the invention to provide one and can expand microwave imaging regional extent can be to arc battle array Row MIMO-SAR echo-signal carries out MIMO-SAR formation method and the device of effective imaging processing.

To achieve these goals, the present invention provides a kind of MIMO-SAR based on arcuate array antenna Formation method, the method includes: adopt the echo-signal received via described arcuate array antenna Sample, wherein, this echo-signal is that the microwave signal launched by described arcuate array antenna is through observation scene Reflect to form；According to sampling angle interval, received echo-signal is arranged, obtain arc Array image-forming data；Described arcuate array imaging data is carried out distance to inverse Fourier transform, obtain away from Signal after tripping contracting；Signal after described Range compress is gone tiltedly and Residual video phase compensates；To warp Described go tiltedly and Residual video phase compensate after the signal that obtains carry out distance to Fourier transformation, obtain Distance wave-number domain signal；Described distance wave-number domain signal is filtered and coherent superposition imaging processing, To image pixel value；And generate image based on described image pixel value.

Preferably, described distance wave-number domain signal is filtered and coherent superposition imaging processing, obtains figure As the step of pixel value includes: be created as coordinate space, empty to the image corresponding with described observation scene Between carry out discretization；Determine that coordinate position that in the image space of discretization, each pixel is corresponding is to described arc The distance of the equivalent sampling point of shape array antenna, and generate adaptation function according to this distance；And based on institute State distance wave-number domain signal and described adaptation function to determine described image pixel value.

Preferably, described adaptation function is determined in the following manner:

$H_M(\mathrm{\θ},R_{\mathrm{arc}},h_0;n_{\mathrm{rr}}\mathrm{\Δ}{\mathrm{rr}}_I,n_{\mathrm{\θ}}\mathrm{\Δ}{\mathrm{\θ}}_I)=\exp \{-j2K_{\mathrm{\ω}}\sqrt{[X_n^2+Y_n^2+Z_n^2}\}$

Wherein,

$\left\{\begin{array}{c}{X}_n=R_{\mathrm{arc}}\cos \mathrm{\θ}-\left\{\right[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\Δ}{\mathrm{rr}}_I]\\ \×\cos [{\mathrm{\θ}}_{\min }+(n_{\mathrm{\θ}}-1)\mathrm{\Δ}{\mathrm{\θ}}_I]\}\sin {\mathrm{\φ}}_{\mathrm{inc}}\\ Y_n=R_{\mathrm{arc}}\sin \mathrm{\θ}-\left\{\right[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\Δ}{\mathrm{rr}}_I]\\ \×\sin [{\mathrm{\θ}}_{\min }+(n_{\mathrm{\θ}}-1)\×\mathrm{\Δ}{\mathrm{\θ}}_I]\}\sin {\mathrm{\φ}}_{\mathrm{inc}}\\ Z_n=h_0-[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\Δ}{\mathrm{rr}}_I]\cos {\mathrm{\φ}}_{\mathrm{inc}}\end{array}\right.$

Wherein, H_M(θ,R_arc,h₀；n_rrΔrr_I,n_θΔθ_I) represent described adaptation function；h₀For arcuate array sky The height of line；R_arcFor equivalent sampling point radius；K_ωRepresent that distance is to wave-number domain frequency；θ is arc battle array Array antenna angle direction；rr_nearLow coverage is observed for arcuate array antenna；θ_minCorresponding for observation field scene area Minimum angles；Δrr_IFor along oblique distance to the pixel separation to observation field scene area；Δθ_IFor arcuately battle array The column direction pixel separation to observation field scene area；n_rrAnd n_θRepresent pixel counts sequence number；X_n、Y_nAnd Z_n Represent image I (n respectively_rrΔrr_I,n_θΔθ_I(n in)_rr,n_θ) coordinate position corresponding to pixel (n_rrΔrr_I,n_θΔθ_I) target corresponding to place be to the equivalent sampling point P of arcuate array antenna_apc(θ,R_arc,h₀) Along X, Y and the distance of Z axis；And φ_incFor the angle with Z axis negative direction.

Preferably, described φ is determined in the following manner_inc:

${\mathrm{\φ}}_{\mathrm{inc}}=\frac{1}{2}[\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{\mathrm{near}}}\right)+\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{\mathrm{far}}}\right)]$

Wherein, rr_farLong distance is observed for arcuate array antenna.

Preferably, the method also includes: show generated figure according to default interval angles, subregion Picture.

The present invention also provides for a kind of MIMO-SAR imaging device based on arcuate array antenna, this device Including: for the module that the echo-signal received via described arcuate array antenna is sampled, its In, this echo-signal is that the microwave signal launched by described arcuate array antenna is through observation scene reflection Become；For received echo-signal being arranged according to sampling angle interval, obtain arc battle array The module of row imaging data；Become to inverse Fourier for described arcuate array imaging data is carried out distance Change, obtain the module of signal after Range compress；For signal after described Range compress is gone oblique and surplus The module that remaining video phase compensates；For to go described in warp tiltedly and Residual video phase compensate after obtain Signal carries out distance to Fourier transformation, obtains the module of distance wave-number domain signal；For to described distance Wave-number domain signal is filtered and coherent superposition imaging processing, obtains the module of image pixel value；And use In the module generating image based on described image pixel value.

Preferably, for described distance wave-number domain signal is filtered and coherent superposition imaging processing, Module to image pixel value includes: be used for being created as coordinate space, to corresponding with described observation scene Image space carry out the module of discretization；In the image space determine discretization, each pixel is corresponding Coordinate position to the distance of the equivalent sampling point of described arcuate array antenna, and generate according to this distance Join the module of function；And for determining institute based on described distance wave-number domain signal and described adaptation function State the module of image pixel value.

Preferably, described adaptation function is determined in the following manner:

$H_M(\mathrm{\θ},R_{\mathrm{arc}},h_0;n_{\mathrm{rr}}\mathrm{\Δ}{\mathrm{rr}}_I,n_{\mathrm{\θ}}\mathrm{\Δ}{\mathrm{\θ}}_I)=\exp \{-j2K_{\mathrm{\ω}}\sqrt{[X_n^2+Y_n^2+Z_n^2}\}$

Wherein,

$\left\{\begin{array}{c}{X}_n=R_{\mathrm{arc}}\cos \mathrm{\θ}-\left\{\right[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\Δ}{\mathrm{rr}}_I]\\ \×\cos [{\mathrm{\θ}}_{\min }+(n_{\mathrm{\θ}}-1)\mathrm{\Δ}{\mathrm{\θ}}_I]\}\sin {\mathrm{\φ}}_{\mathrm{inc}}\\ Y_n=R_{\mathrm{arc}}\sin \mathrm{\θ}-\left\{\right[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\Δ}{\mathrm{rr}}_I]\\ \×\sin [{\mathrm{\θ}}_{\min }+(n_{\mathrm{\θ}}-1)\×\mathrm{\Δ}{\mathrm{\θ}}_I]\}\sin {\mathrm{\φ}}_{\mathrm{inc}}\\ Z_n=h_0-[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\Δ}{\mathrm{rr}}_I]\cos {\mathrm{\φ}}_{\mathrm{inc}}\end{array}\right.$

Wherein, H_M(θ,R_arc,h₀；n_rrΔrr_I,n_θΔθ_I) represent described adaptation function；h₀For arcuate array sky The height of line；R_arcFor equivalent sampling point radius；K_ωRepresent that distance is to wave-number domain frequency；θ is arc battle array Array antenna angle direction；rr_nearLow coverage is observed for arcuate array antenna；θ_minCorresponding for observation field scene area Minimum angles；Δrr_IFor along oblique distance to the pixel separation to observation field scene area；Δθ_IFor arcuately battle array The column direction pixel separation to observation field scene area；n_rrAnd n_θRepresent pixel counts sequence number；X_n、Y_nAnd Z_n Represent image I (n respectively_rrΔrr_I,n_θΔθ_I(n in)_rr,n_θ) coordinate position corresponding to pixel (n_rrΔrr_I,n_θΔθ_I) target corresponding to place be to the equivalent sampling point P of arcuate array antenna_apc(θ,R_arc,h₀) Along X, Y and the distance of Z axis；And φ_incFor the angle with Z axis negative direction.

Preferably, described φ is determined in the following manner_inc:

${\mathrm{\φ}}_{\mathrm{inc}}=\frac{1}{2}[\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{\mathrm{near}}}\right)+\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{\mathrm{far}}}\right)]$

Wherein, rr_farLong distance is observed for arcuate array antenna.

Preferably, this device also includes: for being generated according to default interval angles, subregion display The module of image.

The MIMO-SAR formation method provided by the present invention and device, can effectively solve arc The imaging processing problem of array antenna signals, be a kind of novel, be effectively used for arcuate array antenna Formation method.Further, the precision of obtained image information is higher, and verity is strong.Additionally, due to adopt Carry out signal transmitting and receiving with arcuate array antenna, effectively prevent conventional linear array image-forming observation scope by single The problem of the beam angle constraint of individual antenna, it is possible to realize big field range imaging observation, and improve sight Survey precision.When observation platform geo-stationary, carry out microwave signal transmitting-receiving based on arcuate array antenna, still So can realize platform surrounding is carried out microwave imaging perception, even 360 ° comprehensive scenes. Additionally, use arcuate array antenna configuration, its array does not increases with beam area to resolution and reduces, Can keep relative stability, the high-resolution imaging observation being thus advantageous to around observation platform.

Other features and advantages of the present invention will be described in detail in detailed description of the invention part subsequently.

Accompanying drawing explanation

Accompanying drawing is used to provide a further understanding of the present invention, and constitutes the part of description, with Detailed description below is used for explaining the present invention together, but is not intended that limitation of the present invention.? In accompanying drawing:

Fig. 1 be the present invention provide the arcuate array antenna for MIMO-SAR imaging, for The microwave signal receive-transmit system of MIMO-SAR imaging and MIMO-SAR imaging system are applied One example platforms；

Fig. 2 a is three-dimensional layout's design sketch of arcuate array antenna；

Fig. 2 b is the layout design sketch that arc line array antenna tangentially launches；

Fig. 2 c is the downward projection design sketch of arc line array antenna；

Fig. 3 shows the microwave signal for MIMO-SAR imaging according to the embodiment of the present invention The structural representation of receive-transmit system；

Fig. 4 shows the structural representation of microwave switch network；

Fig. 5 shows the structural representation of MIMO transceiver module；

Fig. 6 shows the transmitting-receiving of MIMO microwave signal receive-transmit system according to the embodiment of the present invention Sequencing contro schematic diagram；

Fig. 7 shows MIMO-SAR imaging based on arcuate array according to the embodiment of the present invention The structural representation of system；

Fig. 8 shows MIMO-SAR based on arcuate array antenna according to the embodiment of the present invention The flow chart of formation method；And

Fig. 9 shows arcuate array antenna MIMO-SAR imaging coordinate system.

Detailed description of the invention

Below in conjunction with accompanying drawing, the detailed description of the invention of the present invention is described in detail.It should be appreciated that Detailed description of the invention described herein is merely to illustrate and explains the present invention, is not limited to this Bright.

Fig. 1 show the arcuate array antenna for MIMO-SAR imaging that the present invention provides, for The example platforms that the microwave signal receive-transmit system of MIMO-SAR imaging is applied.As it is shown in figure 1, Described arcuate array antenna 1 and described microwave signal receive-transmit system etc. all can be loaded in aircraft platform On 22, and move with this aircraft platform 22.Microwave signal receive-transmit system can pass through arcuate array antenna 1 carries out microwave signal radiation, and this microwave signal reflects to form echo-signal, then warp via observation scene 21 Described echo-signal is received by arcuate array antenna 1.Afterwards, through MIMO-SAR provided by the present invention Formation method carries out imaging display process to echo-signal, to demonstrate the image of observation scene 21.As Shown in Fig. 1, owing to carrying out microwave signal transmitting-receiving based on arcuate array antenna, thus compared to linear array Antenna, it is possible to achieve wider array of observation scope.

The embodiment party of the arcuate array antenna 1 that the present invention provides is described in detail below in conjunction with Fig. 2 a-Fig. 2 c Formula.

Fig. 2 a is three-dimensional layout's design sketch of arcuate array antenna 1, and Fig. 2 b is arc line array antenna 1 edge The tangential layout design sketch launched, and the downward projection design sketch that Fig. 2 c is arc line array antenna 1. In view of receive-transmit isolation and dynamic range, arcuate array antenna 1 uses bistatic structure, i.e. launches Antenna and reception antenna are separately.Such as, as shown in Fig. 2 a-Fig. 2 c, arcuate array antenna 1 can include Arc emission array antenna 101 (that is, " AC ") and arc receiving array antenna 102 (that is, " BD "). Described arc emission array antenna 101 is used for radiating microwave signal, in this arc emission array antenna 101 Each independent transmission bay (such as, T₁、T₂、T₃、T_n、......、T_N, wherein, 1≤n ≤ N) can arcuately bearing of trend arrangement.Described arc receiving array antenna 102 is used for receiving echo (this echo-signal is that the microwave signal radiated through arc emission array antenna 101 is passed through such as to observe to signal The microwave signal that scene 21 is reflected back), and this arc receiving array antenna 102 can be with described arc Emission array antenna 101 is neighbouring, each individual reception sky in this arc receiving array antenna 102 Linear array unit (such as, R₁、R₂、R₃、R_n、......、R_N) can arcuately arrange by bearing of trend, and And described each individual reception bay interlocks successively with described each independent transmission bay.Example As, independent transmission bay T₁With individual reception bay R₁And R₂Interleaved adjacent, independent transmission Bay T₂With individual reception bay R₂And R₃Interleaved adjacent, by that analogy.

The radiation of each stand-alone antenna array element (including each reception antenna array element and each launching antenna array unit) Actinal surface is towards outside arc, thus realizes the most round-the-clock, the round-the-clock microwave to platform peripheral region Imaging observation.

Alternatively, described arc receiving array antenna 102 can also be with described arc emission array antenna Inside and outside 101 adjacent, i.e. described arcuate array antenna 1 is by inside and outside mutually sheathed arc receiving array sky Line 102 and arc emission array antenna 101 are formed.Further, each individual reception bay is with each Independent transmission bay interlocks successively.In this embodiment, each stand-alone antenna array element (includes every Individual reception antenna array element and each launching antenna array unit) radiation actinal surface can also be towards outside arc, only But with arc receiving array antenna 102 and arc emission array antenna 101 phase of neighbouring layout Ratio, its radiation actinal surface needs have an angle with horizontal direction so that signal can pass through arc emission array Antenna 101 and arc receiving array antenna 102 are launched with an incident angle and receive, formation etc. Effect sampled point is distributed along circular arc.

In the present invention, for the ease of describing, only with the most adjacently positioned arc emission array antenna 101 Illustrate with as a example by arc receiving array antenna 102.It can be appreciated that, implementation below It is equally applicable to inside and outside adjacently positioned arc emission array antenna 101 and arc receiving array antenna 102。

As shown in Fig. 2 a-Fig. 2 c, in described arc emission array antenna 101, arbitrary neighborhood two is only Vertical launching antenna array unit (such as, T₁With T₂、T₂With T₃Deng) can have level between aperture centre Angular interval Δ θ_Interval, and

$\mathrm{\Δ}{\mathrm{\θ}}_{\mathrm{Interval}}=2\×\arcsin \left(\frac{l_{h\_\mathrm{tr}}}{2R_0}\right)=2\×\arcsin \left(\frac{L_{h\_\mathrm{tr}}+2{\mathrm{\Δl}}_{\mathrm{tr}}}{2R_0}\right)---\left(1\right)$

Wherein, R₀Represent the arc radius of described arc emission array antenna 101；L_{h_tr}Represent that described arc is sent out The independent transmission bay level in array antenna 101 of penetrating is to size；l_{h_tr}Represent that described arc is launched Horizontal range between adjacent two independent transmission bay geometric centers in array antenna 101；Δl_tr For based on L_{h_tr}The parameter determined, and, Δ l_tr∈(0,L_{h_tr})。

Preferably, Δ l_tr=λ_c/ 16, wherein, λ_cFor arcuate array MIMO-SAR imaging system and The operation wavelength of the arcuate array antenna comprised, and L_{h_tr}For λ_cα times, i.e.

L_{h_tr}=α λ_c (2)

Wherein, α is a parameter preset, and α ∈ [0.25,2.00].Accordingly, there exist following proportionate relationship:

Δl_tr=L_{h_tr}/16α (3)

Although it will be understood however, that give Δ l herein_trWith L_{h_tr}Between example proportionate relationship, But the invention is not restricted to this, remaining proportionate relationship is also applied for the present invention.

Additionally, as shown in Fig. 2 a-Fig. 2 c, in described arc receiving array antenna 102, adjacent two Individual reception bay (such as, R₁With R₂、R₂With R₃Deng) can have water between aperture centre Straight angle degree separation delta θ '_Interval, and

${{\mathrm{\Δ\θ}}^{\′}}_{\mathrm{Interval}}=2\×\arcsin \left(\frac{l_{h\_\mathrm{re}}}{{{2R}^{\′}}_0}\right)=2\×\arcsin \left(\frac{L_{h\_\mathrm{re}}+2{\mathrm{\Δl}}_{\mathrm{re}}}{{{2R}^{\′}}_0}\right)---\left(4\right)$

Wherein, R'₀Represent the arc radius of described arc receiving array antenna 102；L_{h_re}Represent described arc Individual reception bay level in receiving array antenna 102 is to size；l_{h_re}Represent that described arc connects Receive the horizontal range between adjacent two independent transmission bay geometric centers in array antenna 102； Δl_reFor based on L_{h_re}The parameter determined, and, Δ l_re∈(0,L_{h_re})。

Similar with described above, it is preferable that Δ l_re=λ_c/ 16, and L_{h_re}For λ_cα times, i.e.

L_{h_tr}=α λ_c (5)

Accordingly, there exist following proportionate relationship:

Δl_re=L_{h_re}/16α (6)

Although it will be understood however, that give Δ l herein_reWith L_{h_re}Between example proportionate relationship, But the invention is not restricted to this, remaining proportionate relationship is also applied for the present invention.

In a preferred embodiment, the independent transmission sky in described arc emission array antenna 101 Linear array unit level is to size L_{h_tr}With the individual reception bay in described arc receiving array antenna 102 Level is to size L_{h_re}Can be equal.Additionally, in described arc emission array antenna 101 adjacent two solely Horizontal range l between vertical launching antenna array unit geometric center_{h_tr}With described arc receiving array antenna 102 In horizontal range l between adjacent two individual reception bay geometric centers_{h_re}Can be equal.The most just It is to say, in this case, Δ l_tr=Δ l_re。

Additionally, in the neighbouring feelings of arc emission array antenna 101 and arc receiving array antenna 102 Under condition, the arc radius R of described arc emission array antenna 101₀With described arc receiving array antenna The arc radius R' of 102₀Can be equal.Further, battle array can be launched by arc due to arcuate array antenna 1 Array antenna 101 and the neighbouring stacking of arc receiving array antenna 102 are constituted, therefore, and arcuate array sky The arc radius of line 1 also with the arc radius R of arc emission array antenna 101₀With arc receiving array sky The arc radius R' of line 102₀Equal.In a preferred embodiment, the choosing of described arc radius The scope of selecting can for example, 0.05m～10.00m.

In this case, the horizontal angle between described adjacent two independent transmission bay aperture centres Degree separation delta θ_IntervalWith the level angle between described adjacent two individual reception bay aperture centres Separation delta θ '_IntervalCan be equal.

As it has been described above, described each individual reception bay depends on described each independent transmission bay Secondary staggered, therefore, an independent transmission bay (example in described arc emission array antenna 101 As, T₁) staggered individual reception adjacent thereto in aperture centre and described arc receiving array antenna 102 Bay (such as, R₁And R₂) can have level angle pitch difference Δ θ between aperture centre_MidInter, And:

${\mathrm{\Δ\θ}}_{\mathrm{MidInter}}=\frac{{\mathrm{\Δ\θ}}_{\mathrm{Interval}}}{2}=\frac{{{\mathrm{\Δ\θ}}^{\′}}_{\mathrm{Interval}}}{2}---\left(7\right)$

Arc emission array antenna 101 and arc receiving array antenna 102 is arranged according to upper type.Institute The sum of the independent transmission bay arranged and the sum of individual reception bay can be equal, and Below equation (8) can be passed through and determine this sum N:

Wherein, θ₀Represent the angular aperture of described arcuate array antenna 1.In a preferred embodiment, arc Angular aperture θ of shape array antenna 1₀The size range of choice be 3 °～360 °.It is to say, the present invention The arcuate array antenna 1 provided can form a perimeter array antenna, thus, it is possible to realize view field 360 ° of full-shape observations of scape 21.For linear array antenna, substantially increase observation scope.

In one embodiment of the invention, described independent transmission bay and described individual reception sky Linear array unit type can be following at least one: slot antenna, microstrip antenna, end-on-fire antenna, Radiating guide, diectric antenna or dipole antenna.It is to say, arc emission array antenna 101 is permissible It is made up of the independent transmission bay of one or more types, and arc receiving array antenna 102 also may be used To be made up of the individual reception bay of one or more types.

Additionally, the polarization side of each independent transmission bay in described arc emission array antenna 101 Formula is consistent, and can be following in one: horizontal polarization, vertical polarization or circular polarisation；And, institute The polarization mode stating each individual reception bay in arc receiving array antenna 102 is consistent, and can Think following in one: horizontal polarization, vertical polarization or circular polarisation.Arc emission array antenna 101 Polarization mode can be consistent with the polarization mode of arc receiving array antenna 102, it is also possible to inconsistent, To this, the present invention is not defined.

The foregoing describe the knot of the arcuate array antenna 1 for MIMO-SAR imaging that the present invention provides Structure.Be described below the present invention provide based on arcuate array antenna 1 carry out microwave signal transmitting-receiving with System and method in MIMO-SAR imaging.

Fig. 3 shows the microwave signal for MIMO-SAR imaging according to the embodiment of the present invention The structural representation of receive-transmit system.As it is shown on figure 3, this microwave signal receive-transmit system may include that MIMO Transceiver module 2, is used for producing and sending microwave signal；Arcuate array antenna 1, including micro-for radiating The arc emission array antenna 101 of ripple signal and for receiving the arc receiving array antenna of echo-signal 102；Microwave switch network 3, for receiving described microwave signal from described MIMO transceiver module 2, From described arc emission array antenna 101, select to radiate the independent transmission antenna array of described microwave signal Unit, and this microwave signal is sent to selected independent transmission bay, with by this independent transmission sky Linear array unit radiates described microwave signal；Described microwave switch network 3 is additionally operable to from described arc receiving array Antenna 102 selects the individual reception bay of echo-signal to be received, and receives from selected The echo-signal of individual reception bay, and this echo-signal is sent to described MIMO transmitting-receiving Module 2；And described MIMO transceiver module 2 is additionally operable to receive described echo-signal, and to this echo Signal processes, to form digital echo signal.

By above it can be seen that in described microwave signal receive-transmit system, first received and dispatched mould by MIMO Block 2 produces a microwave signal, and sends this microwave signal to microwave switch network 3.This microwave switch Network 3 (or in a predetermined sequence) can be sent out from described arc under the control of peripheral control unit Penetrate the independent transmission bay selecting to radiate described microwave signal in array antenna 101.Afterwards, micro- Ripple switching network 3 can control to turn between selected independent transmission bay, and by described micro- Ripple signal sends to this independent transmission bay, to be radiated by it.

Afterwards, microwave signal forms echo-signal after such as observing scene 21 reflection.Similarly, micro- Ripple switching network 3 (or in a predetermined sequence) can come from described under the control of peripheral control unit Arc receiving array antenna 102 selects the individual reception bay of echo-signal to be received.Afterwards, Microwave switch network 3 can control to turn between selected individual reception bay, and receives Echo-signal from selected individual reception bay.Afterwards, then by this echo-signal it is sent to institute State MIMO transceiver module 2, to be carried out signal processing by this MIMO transceiver module 2.

Preferably, microwave switch network 3 can select to radiate the independent transmission sky of described microwave signal While linear array unit, also select the individual reception bay of echo-signal to be received.Further, controlling And between selected independent transmission bay while conducting, also control and selected individual reception Turn between bay.As such, it is possible to make transmitting signal echo-signal after observation scene reflectivity Enter reception antenna array element, MIMO transceiver module.

In a preferred embodiment of the present invention, selected reception antenna array element is with selected The reception antenna array element of launching antenna array unit interleaved adjacent.Such as, with the arc battle array shown in Fig. 2 a-Fig. 2 c As a example by array antenna, it is assumed that microwave switch network 3 selects launching antenna array unit T₁Carry out microwave signal transmitting, The reception antenna array element being then used for receiving echo-signal is and this launching antenna array unit T₁Connecing of interleaved adjacent Receive bay R₁And R₂.If selecting launching antenna array unit T₂Carry out microwave signal transmitting, be then used for The reception antenna array element receiving echo-signal is and this launching antenna array unit T₂The reception antenna of interleaved adjacent Array element R₂And R₃, by that analogy.

Microwave switch network 3 controls the detailed process of the switching of launching antenna array unit and reception antenna array element such as Lower described.

As shown in Figure 4, microwave switch network 3 can include emission array switching network 301, receive battle array Row switching network 302, driver 303 and microwave switch Centralized Controller 304.Emission array switch net Network 301 transmits, by different switching network switchings, the microwave letter that MIMO transceiver module 2 produces one by one Number to arc emission array antenna 101, receiving array switching network 302 is by arc receiving array antenna 102 Receive the echo-signal feeding MIMO transceiver module 2 that observation scene 21 reflects.

It is illustrated as a example by the radial antenna array 1 shown in Fig. 2 a-Fig. 2 c below.Microwave switch is concentrated Controller 304 controls emission array switching network 301 by driver 303 and selects microwave switch break-make sequence Number, so that the microwave signal that MIMO transceiver module 2 produces passes sequentially through emission array switching network 301 Interface 3011 (mono signal passage) and interface 3012, from independent transmission bay T₁Give off. Receiving array switching network 302 selects individual reception bay R₁And R₂Receive echo-signal.Afterwards, Described echo-signal passes sequentially through interface 3022 (dual signal passage) and interface 3021 enters MIMO and receives Send out module 2.

The microwave signal that MIMO transceiver module 2 produces passes sequentially through connecing of emission array switching network 301 Mouthfuls 3011 and interface 3012, from stand-alone antenna array element T₂Give off.Receiving array switching network 302 selects Select individual reception bay R₂And R₃Receive echo-signal.Afterwards, described echo-signal passes sequentially through Interface 3022 and interface 3021 enter MIMO transceiver module 2.

The microwave signal that MIMO transceiver module 2 produces passes sequentially through connecing of emission array switching network 301 Mouthfuls 3011 and interface 3012, from independent transmission bay T₃Give off.Receiving array switching network 302 select individual reception bay R₃And R₄Receive echo-signal.Afterwards, described echo-signal depends on Secondary enter MIMO transceiver module 2 by interface 3022 and interface 3021.

By that analogy, until the microwave signal that MIMO transceiver module 2 produces passes sequentially through emission array The interface 3011 of switching network 301 and interface 3012, from independent transmission bay T_NGive off.Connect Receive array switch network 302 and select individual reception bay R_N(because shown in Fig. 2 a-Fig. 2 c In arcuate array antenna 1, with independent transmission bay T_NThe reception antenna array element of interleaved adjacent only has Reception antenna array element R_N) receive echo-signal.Afterwards, described echo-signal passes sequentially through interface 3022 MIMO transceiver module 2 is entered with interface 3021.

Receive and dispatch process through above microwave signal, as shown in Figure 2 c, 2N-1 equivalent sampling can be formed Point: P_apc(θ=θ_m, R_arc, h₀), m=1 ..., (2N-1), wherein, θ is arcuate array aerial angle direction, θ=θ_mRepresent m-th equivalent sampling point P_apcThe angle coordinate of position coordinates, h₀For arcuate array sky The height of line 1, and R_arcFor equivalent sampling point radius.Below equation (9) can be passed through determine Effect sampled point radius R_arc:

R_arc=R₀tan(Δθ_Interval/2) (9)

Interlaced arrangement mode due to arcuate array antenna 1 so that have between adjacent two equivalent sampling points Equivalent sampling angle is had to be spaced θ_s, and θ_s=Δ θ_Interval/2.This equivalence sampling angle interval θ_sWith above The level angle pitch difference Δ θ described_MidInterEqual.

Emission array switching network 301 and emission array switching network 302 can be opened by multiple single-pole single-throw(SPSTs Pass or single-pole double throw or hilted broadsword eight are thrown PIN switch and are constituted, it is also possible to by multiple single-pole single-throw switch (SPST)s or hilted broadsword Double-throw or hilted broadsword eight are thrown ferrite switch and are constituted.Logically can throw emission array by equivalence formation hilted broadsword N Switch and 2 groups of hilted broadsword N/2 throw switches, thus realize that simultaneously riches all the way and penetrate two-way receiving.Each switch Comprise one to have for the driver 303 controlling microwave switch passage break-make, whole microwave switch network 3 Have a microwave switch Centralized Controller 304, be connected with each driver 303, and by LAN or RS232 is connected with peripheral control unit (not shown), controls each road flexibly by this peripheral control unit and opens Close break-make.

Fig. 5 shows the structural representation of MIMO transceiver module 2 according to the embodiment of the present invention. Describe MIMO transceiver module 2 is how to carry out microwave signal transmitting, connect in detail below in conjunction with Fig. 5 The method received and process.

As it is shown in figure 5, described MIMO transceiver module 2 may include that microwave signal generation unit 201, For producing described microwave signal, and send described micro-to described microwave switch network 3 and power splitter 202 Ripple signal；Described power splitter 202, this power splitter 202 has an input 2021 and multiple outfan (such as, outfan 2022 and 2023), for receiving described microwave letter via described input 2021 Number, and this microwave signal is divided into many ways microwave signal, and come one by one via the plurality of outfan The described many ways microwave signal of corresponding transmission；Multiple reception unit (such as, receive unit 203 and 204), Each reception unit is for receiving the echo-signal from a selected reception antenna array element；And it is many Individual processing unit (such as, processing unit 205 and 206), each processing unit and described power splitter 202 Each outfan connect one to one, and connect one to one with each reception unit, for from right The reception unit answered receives described echo-signal, receives described sub-microwave signal from corresponding outfan, with And based on received sub-microwave signal, received echo-signal is processed, described to be formed Digital echo signal.

Specifically, as it is shown in figure 5, microwave signal generation unit 201 can include MIMO transmitting-receiving control Device 2016 processed, frequency source 2011, amplifier 2012, bonder 2013 (or replacing with power splitter), Amplifier 2014 and amplifier 2015.First, MIMO transceiver controller 2016 by LAN or RS232 is connected with peripheral control unit (not shown).Under the control of peripheral control unit, pass through MIMO Transceiver controller 2016 controls frequency source 2011 and produces microwave signal.This microwave signal is through amplifier Being transferred into bonder 2013 (or replacing with power splitter) after 2012 amplifications, output two-way is identical afterwards Microwave signal.By from microwave after two way microwave signals amplified device 2014 respectively and amplifier 2015 amplification Signal generation unit 201 exports, and wherein, this two way microwave signals can be respectively labeled as S_tr(t) and S_tr'(t).One tunnel microwave signal S_trT () is transferred to emission array switching network 301, and sent out by arc Penetrate array antenna 101 to this microwave signal of external radiation.Another road microwave signal S_tr' (t) be sent to MIMO Power splitter 202 in transceiver module 2.Wherein, t be distance to time variable, and t ∈ [-T_r/2,T_r/ 2], T_rFor signal duration.

Power splitter 202 can have an input 2021 and multiple outfan.In the present invention, for It is easy to illustrate clearly purpose, illustrates as a example by two outfans 2022 and 2023.Power splitter 202 can receive described microwave signal S via described input 2021_tr' (t), and by this microwave signal S_tr' (t) be divided into two way microwave signals S_tr1' (t) and S_tr2' (t), and via said two outfan 2022 Carry out one_to_one corresponding with 2023 and send described two way microwave signals S_tr1' (t) and S_tr2'(t)。

In the reception side of MIMO transceiver module 2, it can include multiple reception unit.As it has been described above, Present invention preferably uses that riches all the way and penetrate the transmitting-receiving mode that two-way receives, therefore, a kind of example embodiment party In formula, MIMO transceiver module 2 can include that two receive unit 203 and 204, each reception unit For receiving from selected reception antenna array element (such as a, R₁Or R₂) echo-signal.

MIMO transceiver module 2 can also include multiple processing unit.For the ease of illustrating clearly purpose, Illustrate as a example by two processing units 205 and 206.As it is shown in figure 5, each processing unit is permissible Connect one to one (such as, processing unit 205 and output with each outfan of described power splitter 202 End 2022 connection, processing unit 206 is connected with outfan 2022), and with each reception unit one One corresponding connect (such as, processing unit 205 is connected with reception unit 203, processing unit 206 with connect Receive unit 204 to connect), for receiving described echo-signal from corresponding reception unit, from corresponding defeated Go out end and receive described sub-microwave signal, and based on received sub-microwave signal, received is returned Ripple signal processes, to form described digital echo signal.

Specifically, (such as, processing unit 205 He of each processing unit in the plurality of processing unit 206) may include that frequency mixer (such as, frequency mixer 2051 and 2061), for from corresponding reception Unit receives described echo-signal, receives described sub-microwave signal from corresponding outfan, and based on being connect The sub-microwave signal received carries out down-converted to received echo-signal；Wave filter is (such as, Wave filter 2052 and 2062) and amplifier (such as, amplifier 2053 and 2063), it is right to be respectively used to The signal obtained after downconverted process is filtered and processing and amplifying；And analog-digital converter is (such as, Analog-digital converter 2054 and 2064), for the signal obtained after described filtering and processing and amplifying is entered Row analog digital conversion, to form described digital echo signal.

Such as, control microwave switch network 3 and make the independent transmission antenna in camber line emission array antenna 101 Array element T_n, individual reception bay R in arc receiving array antenna 102_nAnd R_n+1Simultaneously turn on, Launch signal S_trT () is through independent transmission bay T_nRadiation, reflects, by solely through observation scene 21 Vertical reception antenna array element R_nAnd R_n+1Receive simultaneously, transmit to MIMO transmitting-receiving through microwave switch network 3 Module 2.Reception unit 203 and 204 in MIMO transceiver module 2 receives respectively from individual reception Bay R_nAnd R_n+1Echo-signal, the wave filter 2052 in processing unit 205 and 206 After processing with 2062 and amplifier 2053 and 2063, obtain two-way intermediate-freuqncy signal IF1, IF2, represent For S_re(t, θ=2 (n-1) θ_s) and S_re(t,(2n-1)×θ_s).Mould in processing unit 205 and 206 After number converter 2054 and 2064 is changed, obtain and export two-way digital echo signal DA1, DA2, is expressed as $S_{\mathrm{re}}(n_{f_s},\mathrm{\θ}=2(n-1){\mathrm{\θ}}_s)$ With $S_{\mathrm{re}}(n_{f_s},(2n-1)\×{\mathrm{\θ}}_s),$ Wherein, the initial value of n It is 1.Represent intermediate-freuqncy signal S_re(t, θ=2 (n-1) θ_s) and S_re(t,(2n-1)×θ_s) along time t with Sample frequency f_sCarry out after sample quantizationIndividual sampled point.

Make n=n+1, if n < N, then repeat said process.If n=N, control microwave switch network 3 make the independent transmission bay T in camber line emission array antenna 101_N, arc receiving array antenna 102 In individual reception bay R_NConducting, launches signal S_trT () is through independent transmission bay T_NSpoke Penetrate, reflect, by individual reception bay R through observation scene 21_NReceive, through microwave switch net Network 3 transmits to MIMO transceiver module 2.Echo can be received by the one in multiple reception unit After signal, and the process of frequency mixer, wave filter and the amplifier in corresponding processing unit, To road intermediate-freuqncy signal IF1, it is expressed as S_re(t, θ=2 (N-1) × θ_s).Afterwards, through analog-digital converter After carrying out analog digital conversion, obtain railway digital echo-signal DA1, be expressed as Represent intermediate-freuqncy signal S_re(t, θ=2 (N-1) × θ_s) along time t to adopt Sample frequency f_sCarry out after sample quantizationIndividual sampled point.Now, just complete 2N-1 equivalence The echo signal sample of sampled point.The transmitting-receiving sequencing contro of whole MIMO microwave signal receive-transmit system can With as shown in Figure 6.

Additionally, the present invention also provides for a kind of microwave signal receiving/transmission method for MIMO-SAR imaging. The method includes: produce microwave signal；Arc emission array antenna from arcuate array antenna selects Radiate the independent transmission bay of described microwave signal；By selected independent transmission bay spoke Penetrate described microwave signal；Arc receiving array antenna from described arcuate array antenna selects to receive The individual reception bay of echo-signal；Described echo is received by selected individual reception bay Signal；And received echo-signal is processed, to form digital echo signal.

Additionally, this microwave signal receiving/transmission method can also include: after producing described microwave signal, will This microwave signal is divided into many ways microwave signal；And based on described sub-microwave signal, received is returned Ripple signal processes, to form described digital echo signal.Wherein, based on described sub-microwave signal pair Received echo-signal processes, and includes forming described digital echo signal: based on described son Microwave signal carries out down-converted to received echo-signal；Obtain after downconverted process Signal be filtered and processing and amplifying；And the signal obtained after filtered and processing and amplifying is carried out Analog digital conversion, to form described digital echo signal.

The process of each step in described microwave signal receiving/transmission method and principle microwave the most above in conjunction letter It is consistent that number receive-transmit system describes, and the most just repeats no more.

After completing the signal sampling to 2N-1 equivalent sampling point, i.e. complete based on arcuate array After the microwave signal transmitting-receiving process of antenna, enter into follow-up imaging process.

To this, the present invention also provides for a kind of MIMO-SAR imaging system, as it is shown in fig. 7, should MIMO-SAR imaging system can include the above-mentioned microwave signal receive-transmit system that the present invention provides；And Imaging processor 4, for generating based on the digital echo signal exported by described MIMO transceiver module 2 Image information.Additionally, this imaging system can also include showing processing module 5, it is used for showing described figure As information.

Be described more fully below the present invention provide, by imaging processor 4 and display processing module 5 perform , MIMO-SAR formation method based on arcuate array antenna.

Fig. 8 shows MIMO-SAR based on arcuate array antenna according to the embodiment of the present invention The flow chart of formation method.As shown in Figure 8, the method may include that step S801, to via institute State the echo-signal that arcuate array antenna (such as, arcuate array antenna 1) receives to sample, its In, this echo-signal is that the microwave signal launched by described arcuate array antenna is through observation scene reflection Become；Step S802, arranges received echo-signal according to sampling angle interval, To arcuate array imaging data；Step S803, carries out distance to inverse to described arcuate array imaging data Fourier transformation (IFT), obtains signal after Range compress；Step S804, after described Range compress Signal is carried out tiltedly and Residual video phase compensates；Step S805, to going described in warp tiltedly and remaining video The signal obtained after phase compensation carries out distance to Fourier transformation (FT), obtains distance wave-number domain and believes Number；Step S806, is filtered and coherent superposition imaging processing described distance wave-number domain signal, To image pixel value；And step S807, generate image based on described image pixel value.

The concrete methods of realizing of above-mentioned each step is described below in detail.First, in step S801, right The echo-signal received via described arcuate array antenna is sampled, wherein, this echo-signal be by The microwave signal that described arcuate array antenna is launched reflects to form through observation scene.

In MIMO microwave signal receive-transmit system described above, MIMO transceiver module 2 is the most defeated Go out two digital echo signals, respectively DA1 and DA2.As previously described and shown in Fig. 6 Go out, differ a sampling angle owing to this receives between digital echo signal DA1 with DA2 obtained Interval, receives the digital echo signal DA1 obtained next time and receives the digital echo letter obtained with this Also differ a sampling angle interval between number DA2, therefore, in step S802, can adopt according to described All digital signal DA1 and DA2 received are arranged by sample angle interval, thus obtain arc Array image-forming data S_{re_arc}(t, θ):

$S_{\mathrm{re}\_\mathrm{arc}}(t,\mathrm{\&theta;})=\left[\begin{array}{c}{S}_{\mathrm{re}}(t,\mathrm{\&theta;}=0)\\ S_{\mathrm{re}}(t,\mathrm{\&theta;}={\mathrm{\&theta;}}_s)\\ M\\ S_{\mathrm{re}}(t,\mathrm{\&theta;}=2(N-1){\mathrm{\&theta;}}_s)\end{array}\right]---\left(10\right)$

Obtaining described arcuate array imaging data S_{re_arc}After (t, θ), in step S803, to this arc Array image-forming data S_{re_arc}(t, θ) carries out distance to inverse Fourier transform, i.e. to S_{re_arc}(t, θ) is along distance To carrying out inverse Fourier transform, obtain the signal S after Range compress_{IFT_re_arc}(r, θ):

S_{IFT_re_arc}(r, θ)=IFT_t{S_{re_arc}(t,θ)} (11)

Wherein, IFT_tRepresent and carry out inverse Fourier transform along distance to time variable t, r be echo-signal initial and The observation scene distance variable that end time is corresponding.

Afterwards, in step S705, to the signal S after described Range compress_{IFT_re_arc}(r, θ) is carried out tiltedly And Residual video phase compensates.Following penalty function H (r) can be used S_{IFT_re_arc}(r, θ) carried out tiltedly, Residual video phase compensates:

Wherein, K_rFor signal frequency modulation rate, C is propagation velocity of electromagnetic wave.

Tiltedly and signal S was obtained after Residual video phase compensation through the past_{IFT_RVP}(r, θ):

S_{IFT_RVP}(r, θ)=S_{IFT_re_arc}(r,θ)×H(r) (13)

It follows that in step S804, to the signal tiltedly and obtained after Residual video phase compensation through the past S_{IFT_RVP}(r, θ) carries out distance to Fourier transformation, i.e. to S_{IFT_RVP}(r, θ) along distance to carrying out in Fu Leaf transformation, it is possible to obtain distance wave-number domain signal S_{FT_RVP}(K_ω, θ):

$\begin{array}{c}{S}_{\mathrm{FT}\_\mathrm{RVP}}(K_{\mathrm{\&omega;}},\mathrm{\&theta;})=\mathrm{FT}\left\{S_{\mathrm{IFT}\_\mathrm{RVP}}(r,\mathrm{\&theta;})\right\}\\ =\left[\begin{array}{c}{S}_{\mathrm{re}\_\mathrm{fre}}(K_{\mathrm{\&omega;}},\mathrm{\&theta;}=0)\\ S_{\mathrm{re}\_\mathrm{fre}}(K_{\mathrm{\&omega;}},\mathrm{\&theta;}={\mathrm{\&theta;}}_s)\\ .\\ .\\ .\\ S_{\mathrm{re}\_\mathrm{fre}}(K_{\mathrm{\&omega;}},\mathrm{\&theta;}=(2N-2){\mathrm{\&theta;}}_s)\end{array}\right]\end{array}---\left(14\right)$

Wherein, FT represents Fourier transformation, S_{re_fre}(K_ω, θ) be

$\begin{array}{c}{S}_{\mathrm{re}\_\mathrm{fre}}(K_{\mathrm{\&omega;}},\mathrm{\&theta;})=\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&delta;}}_n(x_n,y_n,z_n)\exp \left\{j2\right[\frac{2\mathrm{\&pi;}(f_c+K_{r}t)}{C}\left]r_n\right\}\\ =\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&delta;}}_n(x_n,y_n,z_n)\exp \left\{j2K_{\mathrm{\&omega;}}{r}_n\right\}\end{array}---\left(15\right)$

Wherein, K_ω=2 π (f_c+K_rT)/C represents that distance is to wave-number domain frequency, f_cFor system operating frequency, r_n For target P_nTo equivalent sampling point P_apcDistance.

It follows that in step S806, described distance wave-number domain signal is filtered and coherent superposition becomes As processing, obtain image pixel value.The detailed process of this step is as follows:

Step S8061: be created as, as coordinate space, the image space of observation scene 21 correspondence being carried out Discretization.Specifically, as it is shown in figure 9, (θ=θ_m,R_arc,h₀), m=1, L, (2N-1) is arcuate array Antenna MIMO forword-looking imaging equivalent sampling point P_apcPosition coordinates, θ is arcuate array aerial angle side To, θ=θ_mRepresent m-th equivalent sampling point P_apcThe angle coordinate of position coordinates, P_nFor observation field Coordinate (the θ of target in scape 21_n,rr_n,φ_n), θ_nFor target P_nAzimuth, φ_nFor target P_nThe angle of pitch, rr_nFor target P_nTo the distance in the arcuate array antenna center of circle, rr_nearLow coverage is observed for arcuate array antenna 1, rr_farLong distance, θ is observed for arcuate array antenna 1_minAnd θ_maxFor the minimum that observation scene 21 region is corresponding Angle and maximum angle, and θ₀=θ_max-θ_min, θ₀Represent the angular aperture size of arcuate array antenna；Right The image of observation scene 21 correspondence carries out two-dimensional discrete, specifically:

With Δ rr_IWith Δ θ_IPixel separation respectively along oblique distance to arcuate array direction to observation scene 21 district Territory carries out two-dimensional discrete, obtains two dimension slant-range image space I (n_rrΔrr_I,n_θΔθ_I), wherein, n_rr=1,2, L, N_rr, n_θ=1,2 ..., N_θ, N_rrAnd N_θBe respectively along oblique distance to arcuate array direction from Pixel number after dispersion, wherein,

Wherein, C is propagation velocity of electromagnetic wave, λ_cBy arcuate array MIMO-SAR imaging system and wrapped The operation wavelength of the arcuate array antenna contained, signal bandwidth is B_r=K_rT_r, signal duration is T_r, Signal frequency modulation rate is K_r, β_rrAnd β_θFor weight coefficient, R₀For the arc radius of arc line array antenna 1, θ_AFor arc emission array antenna 101 and the wave beam width of arc receiving array antenna 102 stand-alone antenna array element Degree, N_θSynAperRepresent and be effectively synthesized the equivalent sampling point P that aperture is comprised_apc(θ,R_arc,h₀) quantity, Δrr_IWith Δ θ_IBe respectively along oblique distance to arcuate array direction to observation scene 21 region pixel separation.

Afterwards, in step S8062: by the distance wave-number domain signal that step S805 is obtained S_{FT_RVP}(K_ω, θ) it is filtered and coherent superposition, circulation solves each pixel value of image.

In view of observation area is carried out two-dimensional imaging, then select to carry out two-dimensional imaging in angle of incidence plane Process, namely do not consider the φ of target in observation field scene area_nChange, φ_nFor target P_nThe angle of pitch, and Being that target projection to fixing oblique distance curved surface carries out two-dimensional imaging, corresponding oblique distance curved surface selects to bear with Z axis Angular separation is φ_incCurved surface on；

${\mathrm{\&phi;}}_{\mathrm{inc}}=\frac{1}{2}[\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{\mathrm{near}}}\right)+\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{\mathrm{far}}}\right)]---\left(17\right)$

Wherein, h₀For arcuate array antenna height, rr_nearLow coverage, rr is observed for arcuate array antenna 1_far Long distance, φ is observed for arcuate array antenna 1_incAlso illustrate that arcuate array antenna angle of incidence, be one to preset often Amount.

Specifically: first, in step S80621: make n_rr=1, n_θ=1, wherein n_rrAnd n_θRepresent picture Element counting sequence number.Afterwards, step S80622: calculate image I (n_rrΔrr_I,n_θΔθ_I(n in)_rr,n_θ) as Coordinate position (the n that element is corresponding_rrΔrr_I,n_θΔθ_I) to the equivalent sampling point of arcuate array antenna 1 P_apc(θ,R_arc,h₀) distance, and according to this distance generate adaptation function H_M(θ,R_arc,h₀；n_rrΔrr_I,n_θΔθ_I):

$H_M(\mathrm{\&theta;},R_{\mathrm{arc}},h_0;n_{\mathrm{rr}}\mathrm{\&Delta;}{\mathrm{rr}}_I,n_{\mathrm{\&theta;}}\mathrm{\&Delta;}{\mathrm{\&theta;}}_I)=\exp \{-j2K_{\mathrm{\&omega;}}\sqrt{[X_n^2+Y_n^2+Z_n^2}\}---\left(18\right)$

Wherein,

$\left\{\begin{array}{c}{X}_n=R_{\mathrm{arc}}\cos \mathrm{\&theta;}-\left\{\right[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\&Delta;}{\mathrm{rr}}_I]\\ \&times;\cos [{\mathrm{\&theta;}}_{\min }+(n_{\mathrm{\&theta;}}-1)\mathrm{\&Delta;}{\mathrm{\&theta;}}_I]\}\sin {\mathrm{\&phi;}}_{\mathrm{inc}}\\ Y_n=R_{\mathrm{arc}}\sin \mathrm{\&theta;}-\left\{\right[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\&Delta;}{\mathrm{rr}}_I]\\ \&times;\sin [{\mathrm{\&theta;}}_{\min }+(n_{\mathrm{\&theta;}}-1)\&times;\mathrm{\&Delta;}{\mathrm{\&theta;}}_I]\}\sin {\mathrm{\&phi;}}_{\mathrm{inc}}\\ Z_n=h_0-[{\mathrm{rr}}_{\mathrm{near}}+(n_{\mathrm{rr}}-1)\mathrm{\&Delta;}{\mathrm{rr}}_I]\cos {\mathrm{\&phi;}}_{\mathrm{inc}}\end{array}\right.---\left(19\right)$

Wherein, X_n、Y_nAnd Z_nRepresent image I (n respectively_rrΔrr_I,n_θΔθ_I(n in)_rr,n_θ) seat corresponding to pixel Cursor position (n_rrΔrr_I,n_θΔθ_I) target corresponding to place be to the equivalent sampling point of arcuate array antenna 1 P_apc(θ,R_arc,h₀) along X, Y and the distance of Z axis.

Afterwards, step S80623: based on described distance wave-number domain signal and described adaptation function, determine (the n of image_rr,n_θ) numerical value corresponding to individual pixel.Specifically:

$\begin{array}{c}I(n_{\mathrm{rr}}{\mathrm{\&Delta;rr}}_I,n_{\mathrm{\&theta;}}{\mathrm{\&Delta;\&theta;}}_I)\\ ={\&Integral;}_{{\mathrm{\&theta;}}_{\mathrm{int}\_\min }}^{{\mathrm{\&theta;}}_{\mathrm{int}\_\max }}[{\&Integral;S}_{\mathrm{FT}\_\mathrm{RVP}}(K_{\mathrm{\&omega;}},\mathrm{\&theta;})\&times;H_M(\mathrm{\&theta;},R_{\mathrm{arc}},h_0;n_{\mathrm{rr}}{\mathrm{\&Delta;rr}}_I,n_{\mathrm{\&theta;}}{\mathrm{\&Delta;\&theta;}}_I)d{K}_{\mathrm{\&omega;}}]\mathrm{d\&theta;}\end{array}---\left(20\right)$

Wherein, θ_{int_min}And θ_{int_max}Represent the integrating range of θ, θ_{int_min}And θ_{int_max}Represent integration respectively Lower limit and upper limit of integral, the respectively corresponding arc synthetic aperture minimum sampling angle value relative to target and Big sampling angle value, and:

$\left\{\begin{array}{c}{\mathrm{\&theta;}}_{\mathrm{int}\_\min }=\min [{\mathrm{\&theta;}}_{\min }+(n_{\mathrm{\&theta;}}-1-\frac{N_{\mathrm{\&theta;SynAper}}}{2}),{\mathrm{\&theta;}}_{\min }]\\ {\mathrm{\&theta;}}_{\mathrm{int}\_\max }=\min [{\mathrm{\&theta;}}_{\min }+(n_{\mathrm{\&theta;}}-1+\frac{N_{\mathrm{\&theta;SynAper}}}{2}),{\mathrm{\&theta;}}_{\max }]\end{array}\right.---\left(21\right)$

Afterwards, step S80624: make n_rrAdd 1, if n_rr≤N_rr, and it is back to step S80622；If n_rr＞ N_rr, continue executing with step S80625；

Step S80625: make n_θAdd 1, if n_θ≤N_θ, make n_rr=1, and it is back to step S80622； If n_θ＞ N_θ, continue executing with step S707.

Finally, in step S807: generate image based on described image pixel value.Specifically, can make I_amp(n_rrΔrr_I,n_θΔθ_I)=| I (n_rrΔrr_I,n_θΔθ_I) |, wherein, | * | represents the range value taking " * ", from And generate two-dimensional image I_amp(n_rrΔrr_I,n_θΔθ_I)。

Above-mentioned imaging process can be completed by imaging processor 4, and this imaging processor 4 can be Computer or dsp processor.Can be by image display 5 to two dimensional image I_amp(n_rrΔrr_I,n_θΔθ_I) complete high-resolution microwave image and show, check for user.

Due to I_amp(n_rrΔrr_I,n_θΔθ_I) contain observation area polarizers of big angle scope scene information, therefore, In a preferred embodiment of the present invention, can carry out to use angle, subregional mode at equal intervals Display.Such as, if θ_min=0rad.=0 °, θ_max=2 π rad.=360 °, wherein " rad. " represents arc Degree, θ_minAnd θ_maxThe minimum angles corresponding for observation field scene area and maximum angle, then can be by grade between Every angle delta θ_dis=10 °, subregion Δ θ_segThe two dimensional image of=60 ° of display observation scenes I_amp(n_rrΔrr_I,n_θΔθ_I), i.e. 0 °～60 °, 10 °～70 ° ..., 350 °～50 °.Such as another example, If θ_min=0rad.=0 °, θ_max=π rad.=180 °, then by angle delta θ at equal intervals_dis=10 °, subregion Δθ_segThe two-dimensional image I of=60 ° of display observation scenes_amp(n_rrΔrr_I,n_θΔθ_I), i.e. 0 °～60 °, 10 °～70 ° ..., 120 °～180 °, 0 °～60 °.It should be appreciated that above-mentioned angle value at equal intervals and Subregion thresholding is all exemplary, is merely to illustrate the present invention, rather than limits the present invention.Other etc. Angular interval angle value and subregion thresholding are also applied for the present invention.

Alternatively, it is also possible to all the image information of scene is observed in display, the most all show two dimension Image I_amp(n_rrΔrr_I,n_θΔθ_I).Such as, if θ_min=0rad.=0 °, θ_max=2 π rad.=360 °, then The two-dimensional image I of 0 °～360 ° observation scene can be directly displayed_amp(n_rrΔrr_I,n_θΔθ_I).As another shows Example, if θ_min=0rad.=0 °, θ_max=π rad.=180 °, then can directly display observation scene 0 °～180 ° of two-dimensional image I_amp(n_rrΔrr_I,n_θΔθ_I)。

Thus, complete MIMO-SAR imaging processing based on arcuate array aerial signal and showed Journey.

The present invention also provides for a kind of MIMO-SAR imaging device based on arcuate array antenna.This device May include that the mould for the echo-signal received via described arcuate array antenna is sampled Block, wherein, this echo-signal is that the microwave signal launched by described arcuate array antenna is through observation scene Reflect to form；For received echo-signal being arranged according to sampling angle interval, obtain The module of arcuate array imaging data；For described arcuate array imaging data is carried out distance in inverse Fu Leaf transformation, obtains the module of signal after Range compress；For signal after described Range compress is gone tiltedly And the module that Residual video phase compensates；For to going described in warp tiltedly and obtaining after Residual video phase compensation To signal carry out distance to Fourier transformation, obtain the module of distance wave-number domain signal；For to described Distance wave-number domain signal is filtered and coherent superposition imaging processing, obtains the module of image pixel value；With And for generating the module of image based on described image pixel value.

Additionally, for described distance wave-number domain signal is filtered and coherent superposition imaging processing, obtain The module of image pixel value includes: be used for being created as coordinate space, to corresponding with described observation scene Image space carries out the module of discretization；In the image space determine discretization, each pixel is corresponding Coordinate position is to the distance of the equivalent sampling point of described arcuate array antenna, and generates coupling according to this distance The module of function；And it is described for determining based on described distance wave-number domain signal and described adaptation function The module of image pixel value.

Additionally, this device includes: for the module of the image that display is generated.

In sum, the present invention provide the arcuate array antenna for MIMO-SAR imaging, be used for The microwave signal receive-transmit system of MIMO-SAR imaging and method and MIMO-SAR imaging system, Method and apparatus, can not only ensure that signal penetrates the materials such as cigarette, mist, cloud layer and floating dust, not by weather And climatic effect, and, compared with conventional imaging system based on linear array antenna, it is also equipped with Following advantage:

1, effectively prevent the conventional linear array image-forming observation scope beam angle by single array-element antenna Problem, it is possible to realize big field range imaging observation.Aircraft just can be to more without frequently moving and rotating The region of wide scope is observed, thus ensures the flight safety of aircraft.

2, use arcuate array configuration and MIMO configuration, its array to resolution not with beam area Increase and reduce, can keep relative stability；

3, using MIMO configuration, during platform geo-stationary, system still can realize platform week Collarette border, even 360 ° comprehensive scenes carry out microwave imaging perception；

4, aircraft peripheral region can be carried out Real-time High Resolution rate imaging, moreover it is possible to for aircraft landing, Scouting, searching and rescuing and taking off provides real terrestrial information, strengthens navigation and the transport rescue ability of aircraft.

Additionally, the present invention provide MIMO-SAR formation method based on arcuate array be a set of completely newly , the method that effectively arcuate array antenna microwave signal can be carried out imaging processing, use the method High-precision microwave imaging can be realized, it is possible to provide more wide, accurate, real for observation personnel Observation information.

The preferred embodiment of the present invention is described in detail above in association with accompanying drawing, but, the present invention does not limit Detail in above-mentioned embodiment, in the technology concept of the present invention, can be to the present invention Technical scheme carry out multiple simple variant, these simple variant belong to protection scope of the present invention.

It is further to note that each the concrete technology described in above-mentioned detailed description of the invention is special Levy, in the case of reconcilable, can be combined by any suitable means.In order to avoid need not The repetition wanted, various possible compound modes are illustrated by the present invention the most separately.

Additionally, combination in any can also be carried out between the various different embodiment of the present invention, as long as its Without prejudice to the thought of the present invention, it should be considered as content disclosed in this invention equally.

Claims (10)

1. a MIMO-SAR formation method based on arcuate array antenna, it is characterised in that the party Method includes:

Sampling the echo-signal received via described arcuate array antenna, wherein, this echo is believed Number it is that the microwave signal launched by described arcuate array antenna reflects to form through observation scene；

According to sampling angle interval, received echo-signal is arranged, obtain arcuate array imaging Data；

Described arcuate array imaging data is carried out distance to inverse Fourier transform, believe after obtaining Range compress Number；

Signal after described Range compress is gone tiltedly and Residual video phase compensates；

The signal gone described in warp tiltedly and obtain after Residual video phase compensation is carried out distance to Fourier Conversion, obtains distance wave-number domain signal；

Described distance wave-number domain signal is filtered and coherent superposition imaging processing, obtains image pixel Value；And

Image is generated based on described image pixel value.

Method the most according to claim 1, it is characterised in that to described distance wave-number domain signal Being filtered and coherent superposition imaging processing, the step obtaining image pixel value includes:

It is created as, as coordinate space, the image space corresponding with described observation scene being carried out discretization；

Determine that coordinate position that in the image space of discretization, each pixel is corresponding is to described arcuate array sky The distance of the equivalent sampling point of line, and generate adaptation function according to this distance；And

Described image pixel value is determined based on described distance wave-number domain signal and described adaptation function.

Method the most according to claim 2, it is characterised in that determine described in the following manner Adaptation function:

$H_M(\mathrm{\&theta;},R_{arc},h_0;n_{rr}{\mathrm{\&Delta;rr}}_I,n_{\mathrm{\&theta;}}{\mathrm{\&Delta;\&theta;}}_I)=\exp \{-j2K_{\mathrm{\&omega;}}\sqrt{\&lsqb;X_n^2+Y_n^2+Z_n^2\&rsqb;}\}$

Wherein,

$\left\{\begin{array}{c}{X}_n=R_{arc}cos\mathrm{\&theta;}-\{\&lsqb;{\mathrm{rr}}_{near}+(n_{rr}-1){\mathrm{\&Delta;rr}}_I\&rsqb;\\ \&times;cos\&lsqb;{\mathrm{\&theta;}}_{\min }+(n_{\mathrm{\&theta;}}-1){\mathrm{\&Delta;\&theta;}}_I\&rsqb;\}{\mathrm{sin\&phi;}}_{inc}\\ Y_n=R_{arc}\sin \mathrm{\&theta;}-\{\&lsqb;{\mathrm{rr}}_{near}+(n_{rr}-1){\mathrm{\&Delta;rr}}_I\&rsqb;\\ \&times;\sin \&lsqb;{\mathrm{\&theta;}}_{\min }+(n_{\mathrm{\&theta;}}-1)\&times;{\mathrm{\&Delta;\&theta;}}_I\&rsqb;\}{\mathrm{sin\&phi;}}_{inc}\\ Z_n=h_0-\&lsqb;{\mathrm{rr}}_{near}+(n_{rr}-1){\mathrm{\&Delta;rr}}_I\&rsqb;{\mathrm{cos\&phi;}}_{inc}\end{array}\right.$

Wherein, H_M(θ, R_arc, h₀；n_rrΔrr_I, n_θΔθ_I) represent described adaptation function；h₀For arcuate array sky The height of line；R_arcFor equivalent sampling point radius；K_ωRepresent that distance is to wave-number domain frequency；θ is arc battle array Array antenna angle direction；rr_nearLow coverage is observed for arcuate array antenna；θ_minCorresponding for observation field scene area Minimum angles；△rr_IFor along oblique distance to the pixel separation to observation field scene area；△θ_IFor arcuately battle array The column direction pixel separation to observation field scene area；n_rrAnd n_θRepresent pixel counts sequence number；X_n、Y_nAnd Z_n Represent image I (n respectively_rr△rr_I,n_θ△θ_I(n in)_rr,n_θ) coordinate position corresponding to pixel (n_rr△rr_I,n_θ△θ_I) target corresponding to place be to the equivalent sampling point P of arcuate array antenna_apc(θ,R_arc,h₀) Along X, Y and the distance of Z axis；And φ_incRepresent arcuate array antenna angle of incidence.

Method the most according to claim 3, it is characterised in that determine described φ in the following manner_inc:

${\mathrm{\&phi;}}_{inc}=\frac{1}{2}\&lsqb;\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{near}}\right)+\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{far}}\right)\&rsqb;$

Wherein, rr_farLong distance is observed for arcuate array antenna.

5. according to the method described in any claim in claim 1-4, it is characterised in that the party Method also includes: show generated image according to default interval angles, subregion.

6. a MIMO-SAR imaging device based on arcuate array antenna, it is characterised in that this dress Put and include:

For the module that the echo-signal received via described arcuate array antenna is sampled, its In, this echo-signal is that the microwave signal launched by described arcuate array antenna is through observation scene reflection Become；

For received echo-signal being arranged according to sampling angle interval, obtain arcuate array The module of imaging data；

For described arcuate array imaging data being carried out distance to inverse Fourier transform, obtain Range compress The module of rear signal；

For module signal after described Range compress gone tiltedly and Residual video phase compensates；

For the signal gone described in warp tiltedly and obtain after Residual video phase compensation is carried out distance to Fu In leaf transformation, obtain distance wave-number domain signal module；

For described distance wave-number domain signal is filtered and coherent superposition imaging processing, obtain image slices The module of element value；And

For generating the module of image based on described image pixel value.

Device the most according to claim 6, it is characterised in that for described distance wave-number domain Signal is filtered and coherent superposition imaging processing, and the module obtaining image pixel value includes:

For being created as coordinate space, the image space corresponding with described observation scene is carried out discretization Module；

The coordinate position that each pixel is corresponding in the image space determine discretization is to described arc battle array The distance of the equivalent sampling point of array antenna, and the module of adaptation function is generated according to this distance；And

For determining described image pixel value based on described distance wave-number domain signal and described adaptation function Module.

Device the most according to claim 7, it is characterised in that determine described in the following manner Adaptation function:

$H_M(\mathrm{\&theta;},R_{arc},h_0;n_{rr}{\mathrm{\&Delta;rr}}_I,n_{\mathrm{\&theta;}}{\mathrm{\&Delta;\&theta;}}_I)=\exp \{-j2K_{\mathrm{\&omega;}}\sqrt{\&lsqb;X_n^2+Y_n^2+Z_n^2\&rsqb;}\}$

Wherein,

$\left\{\begin{array}{c}{X}_n=R_{arc}cos\mathrm{\&theta;}-\{\&lsqb;{\mathrm{rr}}_{near}+(n_{rr}-1){\mathrm{\&Delta;rr}}_I\&rsqb;\\ \&times;cos\&lsqb;{\mathrm{\&theta;}}_{\min }+(n_{\mathrm{\&theta;}}-1){\mathrm{\&Delta;\&theta;}}_I\&rsqb;\}{\mathrm{sin\&phi;}}_{inc}\\ Y_n=R_{arc}\sin \mathrm{\&theta;}-\{\&lsqb;{\mathrm{rr}}_{near}+(n_{rr}-1){\mathrm{\&Delta;rr}}_I\&rsqb;\\ \&times;\sin \&lsqb;{\mathrm{\&theta;}}_{\min }+(n_{\mathrm{\&theta;}}-1)\&times;{\mathrm{\&Delta;\&theta;}}_I\&rsqb;\}{\mathrm{sin\&phi;}}_{inc}\\ Z_n=h_0-\&lsqb;{\mathrm{rr}}_{near}+(n_{rr}-1){\mathrm{\&Delta;rr}}_I\&rsqb;{\mathrm{cos\&phi;}}_{inc}\end{array}\right.$

Wherein, H_M(θ, R_arc, h₀；n_rrΔrr_I, n_θΔθ_I) represent described adaptation function；h₀For arcuate array sky The height of line；R_arcFor equivalent sampling point radius；K_ωRepresent that distance is to wave-number domain frequency；θ is arc battle array Array antenna angle direction；rr_nearLow coverage is observed for arcuate array antenna；θ_minCorresponding for observation field scene area Minimum angles；△rr_IFor along oblique distance to the pixel separation to observation field scene area；△θ_IFor arcuately battle array The column direction pixel separation to observation field scene area；n_rrAnd n_θRepresent pixel counts sequence number；X_n、Y_nAnd Z_n Represent image I (n respectively_rr△rr_I,n_θ△θ_I(n in)_rr,n_θ) coordinate position corresponding to pixel (n_rr△rr_I,n_θ△θ_I) target corresponding to place be to the equivalent sampling point P of arcuate array antenna_apc(θ,R_arc,h₀) Along X, Y and the distance of Z axis；And φ_incRepresent arcuate array antenna angle of incidence.

Device the most according to claim 8, it is characterised in that determine described φ in the following manner_inc:

${\mathrm{\&phi;}}_{inc}=\frac{1}{2}\&lsqb;\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{near}}\right)+\arcsin \left(\frac{h_0}{{\mathrm{rr}}_{far}}\right)\&rsqb;$

Wherein, rr_farLong distance is observed for arcuate array antenna.

10. according to the device described in any claim in claim 6-9, it is characterised in that this dress Put and also include: for showing the module of generated image according to default interval angles, subregion.