CN102141618B - Microwave staring imaging method - Google Patents

Abstract

The embodiment of the invention provides a microwave staring imaging method based on a time and space two-dimensional random radiation field and associative processing, which comprises the following steps that an antenna aperture field is specially required to randomly radiate a target area covered by a wave beam, and forming the noncorrelation characteristic that the radiation field with the time and space two-dimensional random distribution characteristics is required to simultaneously meet the time dimension and the space dimension; and after the radiation field is interacted with a detected target, a receiver is used for receiving an echo scattering field signal and extracting the target space information distribution of an area to be detected through receiving the correlated imaging process of a scattering filed and a known radiation field to realize the microwave staring imaging. With the adoption of the technical scheme provided by the invention, the defect that the traditional real aperture radar spatial resolution depends on the antenna aperture is overcome through the correlated microwave staring imaging of the time and space two-dimensional radiation field, and the high-resolution microwave staring imaging can be realized.

Description

The method of microwave staring imaging

Technical field

The present invention relates to the imaging technique in radar, microwave remote sensing and precise guidance field, particularly, the present invention relates to the method for microwave staring imaging.

Background technology

Traditional real aperture imaging radar comprises beam scanning radar, phased-array radar and focal plane imaging radar etc.For the beam scanning radar, because the restriction of beam coverage need utilize the mechanical scanning mode to change beam direction.As shown in Figure 1, be the antenna beam direction synoptic diagram of routine.The computerized control formation and the scanning of wave beam of phased-array radar replaces mechanical scanning; It satisfies the wave beam of certain distributed characteristic through the phase place and the amplitude of each unit of array of controls antenna to be formed on the space; And can change its scanning and point to, overcome the problem that mechanical scanning brings.The focal plane imaging radar then utilizes inclined to one side Jiao of antenna system, realizes multi-beam, utilizes a plurality of " feeds " to survey the radiation on the focal plane then, utilizes this information to be carried out to picture at last.

The resolution element of real aperture radar imaging is exactly the antenna beam irradiation area, and promptly the spatial resolution of real aperture radar imaging depends on antenna aperture, improve resolution and just must increase antenna size or increase the array number.Specifically, the single beam scanning radar need reduce antenna beamwidth, increases the bore of antenna.The method that phased-array radar improves resolution also is to reduce beam angle in essence, and according to the array blending theory, needing to increase element number of array could realize.The focal plane imaging radar is through polynary one chip detector array is placed the parabolic reflector of larger caliber or the focal plane of lens antenna; Utilize inclined to one side Jiao of feed array, the millimeter-wave radiation energy focusing of the target of collecting, background on two-dimentional feed array.Be similar to optical imagery, its imaging resolution depends on antenna aperture, and it also is bigger improving this system radar resolution difficulty.Real aperture and transmitting of focal plane imaging radar are machine made periodic signal; The different wavefront distribution basically identicals that form radiation field constantly, when radiation field and target interaction, scattered field merges the target information in the wave beam; Though target information lies in the letter in reply signal; But can't extract, promptly to receive the scattered field information that echo comprises all identical at every turn, and accumulation repeatedly can only improve signal to noise ratio (S/N ratio); Can not bring to can be used for the extraneous information that target is differentiated, this is the basic reason that traditional real aperture and focal plane radar imagery resolution depend on antenna aperture.

Therefore, be necessary to propose a kind of otherwise effective technique scheme, solve the lower problem of radar imagery resolution in the prior art.

Summary of the invention

The object of the invention is intended to solve at least one of above-mentioned technological deficiency, passes through the space-time bidimensional microwave staring imaging of radiation field at random especially, overcomes the defective that traditional real aperture radar spatial resolution depends on antenna aperture, realizes high-resolution microwave staring imaging.

The embodiment of the invention has proposed a kind of based on the space-time bidimensional method of the microwave staring imaging of radiation field at random; There is essence different with traditional microwave imaging; The microwave imaging beam radiation becomes to have the antenna actinal surface field of extraordinary random distribution characteristic; No longer be simple point source radiation, but the leggy center radiation, and radiation signal is the random signal through particular modulation.

The method of said microwave staring imaging may further comprise the steps:

The microwave imaging radiate source radiation becomes to have the antenna actinal surface field of extraordinary random distribution characteristic; Radiation is at random carried out in wave beam coverage goal zone; The radiation field at random

that formation has a space-time bidimensional random distribution characteristic had both embodied the random character of time dimension, embodied the random character of space dimension simultaneously;

After radiation field

interacts with detected target; Form the echo scattered field, receive echo scattered field signal

by receiver

The relevance imaging processing is carried out in said echo scattered field signal

and target area radiation field

at random; The target image in inverting and reconstruct zone to be measured is realized the microwave staring imaging.

According to embodiments of the invention, said radiation field

is:

$\mathrm{\Ψ}(\stackrel{\→}{r},t)=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\underset{{S_i}^{\′}}{\∫}g({\stackrel{\→}{r}}_i^T,t^T,\stackrel{\→}{r},t)f({\stackrel{\→}{r}}_i^T,t^T)d{S_i}^{\′},$

Wherein

Be antenna actinal surface field t ^TConstantly, the position does

The complex modulation radiation signal of place's radiation, N is a radiation phase center number, the irradiation area of i radiation signal is S _i',

Be any some positions, plane, overlay area, It is the time domain Green function of the free space of i radiation signal.

According to embodiments of the invention; Radiation field on any different resolution elements in the beam coverage area

all has irrelevant characteristic, and its uncorrelated nature is characterized by:

$I({\stackrel{\&RightArrow;}{r}}_1,{\stackrel{\&RightArrow;}{r}}_2,t)=<{\mathrm{\&Psi;}}^{*}({\stackrel{\&RightArrow;}{r}}_1,t)\mathrm{\&Psi;}({\stackrel{\&RightArrow;}{r}}_2,t)>$

$=\underset{t}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}{g}^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_1,t)f^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\&CenterDot;\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}g({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_2,t)f({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\mathrm{dt}$

$=\underset{t}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}\underset{{S_j}^{\&prime;}}{\&Integral;}R({\stackrel{\&RightArrow;}{r}}_i^T,{\stackrel{\&RightArrow;}{r}}_j^T,t^T)\&CenterDot;g^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_1,t)\&CenterDot;g({\stackrel{\&RightArrow;}{r}}_j^T,t^T,{\stackrel{\&RightArrow;}{r}}_2,t)d{S_i}^{\&prime;}d{S_j}^{\&prime;}\mathrm{dt}$

Wherein, <>expression inner product operation,

is the related function of a plurality of radiation phase center radiation signals.Can know that by following formula this uncorrelated nature is that uncorrelated nature by the chopped radiation signal forms with Green's FUNCTION MODULATION in the observation time section.

According to embodiments of the invention, different moment t ₁, t ₂, having irrelevant characteristic between the radiation field in wave beam coverage goal zone, its uncorrelated nature is characterized by:

$I(\stackrel{\&RightArrow;}{r},{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA0000042698340000021.png"\; state="\{\{state\}\}">t</figure-callout>}}_1,t_2)=<{\mathrm{\&Psi;}}^{*}(\stackrel{\&RightArrow;}{r},t_1)\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t_2)>$

$=\underset{s^{\&prime;}}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}{g}^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_1)f^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\&CenterDot;\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}g({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_2)f({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}d{s}^{\&prime;}.$

$=\underset{s^{\&prime;}}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}\underset{{S_j}^{\&prime;}}{\&Integral;}R({\stackrel{\&RightArrow;}{r}}_i^T,{\stackrel{\&RightArrow;}{r}}_j^T,t^T)\&CenterDot;g^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_1)\&CenterDot;g({\stackrel{\&RightArrow;}{r}}_j^T,t^T,\stackrel{\&RightArrow;}{r},t_2)d{S_i}^{\&prime;}d{S_j}^{\&prime;}d{s}^{\&prime;}$

Can know that by following formula this uncorrelated nature is that uncorrelated nature by the chopped radiation signal forms with Green's FUNCTION MODULATION in the overlay area.

According to embodiments of the invention; The time, empty bidimensional radiation field

random character should on time, space, show as desirable uncorrelated nature, promptly two related function I all level off to zero.

According to embodiments of the invention, said reception echo scattered field signal

is:

$u_r(\stackrel{\&RightArrow;}{r^R},t^R)=\underset{S^{\&prime;}}{\&Integral;}\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t)\mathrm{\&sigma;}\left(r\right)g({\stackrel{\&RightArrow;}{r}}^R,t^R,\stackrel{\&RightArrow;}{r},t)d{S}^{\&prime;}.$

Wherein

Be receiver space position, t ^RBe the time of reception, σ (r) is the detection of a target

The backscattering coefficient of position, Time domain Green function for the free space of RX path.

According to embodiments of the invention, said scattered field when being constant target scattering characteristics to the time radiation field at random that becomes spatial modulation.

According to embodiments of the invention; In order to realize to lying in the extraction and the decoupling zero of the space distribution target information in the scattered field; When carrying out with known radiation field at random to receiving scattered field, the processing of empty bidimensional relevance imaging: wherein; χ { } is related computing; The algorithm of inverting, reconstruct target image is provided, and this algorithm must adapt with scattered field message pick-up and treatment technology.

The such scheme that the present invention proposes, the radiation field in wave beam coverage goal zone demonstrates desirable non-correlation of time and space, has guaranteed the necessary condition of target as reconstruct.Under same observation condition; Increase along with the irradiation number of times; Promptly be presented as the increase of staring imaging time, but the target identification information that is comprised in the scattered field also increase thereupon, as long as guarantee that the quantity of radiation field satisfies the inverting requirement at random; Can the target information that be coupling in scattered field originally be separated the reconstruct target image through radiation field at random and the space-time bidimensional association process that receives scattered field.

Compare with traditional microwave staring imaging method, the such scheme that the present invention proposes has the following advantages at least: can overcome the defective that traditional real aperture radar spatial resolution depends on antenna aperture, realize high-resolution microwave staring imaging; For traditional staring imaging radar, increase gaze duration and only can increase signal to noise ratio (S/N ratio), but can not improve spatial resolution, and, can pass through to increase gaze duration room for promotion resolution effectively for the such scheme that the present invention proposes.

According to embodiments of the invention, the method for said microwave staring imaging based on space-time bidimensional radiation field can be applied on geosynchronous satellite or the hovering platform carrier.

Aspect that the present invention adds and advantage part in the following description provide, and part will become obviously from the following description, or recognize through practice of the present invention.

Description of drawings:

Above-mentioned and/or additional aspect of the present invention and advantage are from obviously with easily understanding becoming the description of embodiment below in conjunction with accompanying drawing, wherein:

Fig. 1 is conventional antenna beam direction synoptic diagram;

Fig. 2 is radiation field synoptic diagram at random;

Fig. 3 is the imageable target synoptic diagram at a distance of 1m;

Fig. 4 is the radiation field synoptic diagram of 10m * sampling when 10m irradiation area resolution is 1m;

Fig. 5 is target image by inversion synoptic diagram during for gaze duration sampling 50 times;

Fig. 6 is target image by inversion synoptic diagram during for gaze duration sampling 100 times;

Fig. 7 is the imageable target synoptic diagram at a distance of 0.2m

Fig. 8 is the radiation field synoptic diagram of 10m * sampling when 10m irradiation area resolution is 0.2m;

Fig. 9 is target image by inversion synoptic diagram during for gaze duration sampling 500 times;

Figure 10 is target image by inversion synoptic diagram during for gaze duration sampling 2500 times;

Figure 11 is that regional scattering coefficient to be measured distributes;

Figure 12 (a) is following 500 gaze durations sampling of a desirable white noise image;

Figure 12 (b) is following 1300 gaze durations sampling of a desirable white noise image;

Figure 12 (c) is following 1800 gaze durations sampling of a desirable white noise image.

Embodiment

Describe embodiments of the invention below in detail, the example of said embodiment is shown in the drawings, and wherein identical from start to finish or similar label is represented identical or similar elements or the element with identical or similar functions.Be exemplary through the embodiment that is described with reference to the drawings below, only be used to explain the present invention, and can not be interpreted as limitation of the present invention.

The core concept of the scheme that the present invention proposes is:

Based on the space-time bidimensional microwave staring imaging new method of radiation field and association process at random, have the actinal surface field of extraordinary random distribution characteristic through structure, form the space radiation field at random that meets specific (special) requirements through propagating in beam coverage area.This moment, aerial radiation was not simple point source radiation; But leggy center radiation; And radiation signal is the random signal through complex modulation; This radiation field has space-time bidimensional random character: in the beam coverage area, the radiation field on any two resolution elements all has irrelevant characteristic, thereby makes different resolution elements show complicated otherness distribution characteristics; Has irrelevant characteristic equally between the different moment radiation field; This characteristic has guaranteed on the target object plane the different irradiations that can receive the radiation field with different otherness distribution characteristicss constantly, and space-time bidimensional random character has constituted the adequate condition of the spatial resolution that realizes surmounting the aperture.When space-time bidimensional when radiation field and target interact at random; Target modulation this radiation field with otherness distribution characteristics; Therefore not only comprised target scattering characteristics in the scattered field; Carried space-time two-dimension radiation field information at random simultaneously, when promptly scattered field is constant target scattering characteristics to the time radiation field at random that becomes spatial modulation, but make scattered field in the wave beam contain the identification space distribution information of target; This information is with the radiation field abundant information degree variation that is directly proportional at random of space-time bidimensional, and this is the core concept that realizes surmounting the spatial resolution of antenna aperture.At random under the radiation field effect, scattered information receives the related information disposal route that adopts the space-time bidimensional random field that adapts with it with treatment technology, extraction and the decoupling zero of realization to lying in target information in the scattered field at this space-time bidimensional.Under equal observation condition; Increase along with the irradiation number of times; It is the increase of staring imaging time; But the target identification information that is comprised in the scattered field also increases thereupon, and repeatedly the fusion of related information has brought the lifting of spatial resolution, and it provides necessary condition for realizing the spatial resolution that surmounts antenna aperture.As shown in Figure 2, be radiation field synoptic diagram at random.

In order to realize the present invention's purpose, the embodiment of the invention has proposed a kind of microwave staring imaging method based on space-time bidimensional radiation field, may further comprise the steps:

The microwave imaging radiate source radiation becomes to have the antenna actinal surface field of extraordinary random distribution characteristic; Radiation is at random carried out in wave beam coverage goal zone, formed when possessing, the radiation field at random

of empty bidimensional random distribution characteristic when its random character shows as, the desirable uncorrelated nature of empty bidimensional; After radiation field

interacts with detected target; Form the echo scattered field; Radiation field

when carrying out, empty bidimensional relevance imaging are handled at random with said reception echo scattered field signal

and target area to receive echo scattered field signal

by receiver; The object space information distribution in reconstruct zone to be measured realizes the microwave staring imaging.

Particularly, radiation field

shows as at random:

$\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t)=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}g({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t)f({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;},$ Wherein

Be antenna actinal surface field t ^TConstantly, the position does

The chopped radiation signal of place's radiation, N is a radiation phase center number, the irradiation area of i radiation signal is S _i',

Be any some positions, plane, overlay area,

It is the time domain Green function of the free space of i radiation signal.

Wherein, Radiation field on any different resolution elements in the wave beam coverage goal zone

has irrelevant characteristic, and its uncorrelated nature is characterized by:

$I({\stackrel{\&RightArrow;}{r}}_1,{\stackrel{\&RightArrow;}{r}}_2,t)=<{\mathrm{\&Psi;}}^{*}({\stackrel{\&RightArrow;}{r}}_1,t)\mathrm{\&Psi;}({\stackrel{\&RightArrow;}{r}}_2,t)>$

$=\underset{t}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}{g}^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_1,t)f^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\&CenterDot;\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}g({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_2,t)f({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\mathrm{dt}$

$=\underset{t}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}\underset{{S_j}^{\&prime;}}{\&Integral;}R({\stackrel{\&RightArrow;}{r}}_i^T,{\stackrel{\&RightArrow;}{r}}_j^T,t^T)\&CenterDot;g^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_1,t)\&CenterDot;g({\stackrel{\&RightArrow;}{r}}_j^T,t^T,{\stackrel{\&RightArrow;}{r}}_2,t)d{S_i}^{\&prime;}d{S_j}^{\&prime;}\mathrm{dt}$

Wherein, <>expression inner product operation, is the related function of a plurality of radiation phase center radiation signals.

Wherein, have irrelevant characteristic between the radiation field in the different wave beam coverage goals constantly zone, its uncorrelated nature is characterized by:

$I(\stackrel{\&RightArrow;}{r},{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA0000042698340000021.png"\; state="\{\{state\}\}">t</figure-callout>}}_1,t_2)=<{\mathrm{\&Psi;}}^{*}(\stackrel{\&RightArrow;}{r},t_1)\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t_2)>$

$=\underset{s^{\&prime;}}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}{g}^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_1)f^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\&CenterDot;\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}g({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_2)f({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}d{s}^{\&prime;}.$

$=\underset{s^{\&prime;}}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}\underset{{S_j}^{\&prime;}}{\&Integral;}R({\stackrel{\&RightArrow;}{r}}_i^T,{\stackrel{\&RightArrow;}{r}}_j^T,t^T)\&CenterDot;g^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_1)\&CenterDot;g({\stackrel{\&RightArrow;}{r}}_j^T,t^T,\stackrel{\&RightArrow;}{r},t_2)d{S_i}^{\&prime;}d{S_j}^{\&prime;}d{s}^{\&prime;}$

In the above-described embodiments, the received echo scattered field of receiver signal

is:

$u_r(\stackrel{\&RightArrow;}{r^R},t^R)=\underset{S^{\&prime;}}{\&Integral;}\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t)\mathrm{\&sigma;}\left(r\right)g({\stackrel{\&RightArrow;}{r}}^R,t^R,\stackrel{\&RightArrow;}{r},t)d{S}^{\&prime;}$

The receiver space position does

Be t the time of reception ^R, σ (r) is the detection of a target

The backscattering coefficient of position,

Time domain Green function for the free space of RX path.

The said method that the present invention proposes, scattered field when being constant target scattering characteristics to the time radiation field at random that becomes spatial modulation.

In order to realize that the target image that lies in the scattered field is carried out inverting and reconstruct, when carrying out with known irrelevant radiation field at random, the processing of empty bidimensional relevance imaging to receiving scattered field:

$\mathrm{\&sigma;}\left(\stackrel{\&RightArrow;}{r}\right)=\mathrm{\&chi;}\{\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t),u_r(\stackrel{\&RightArrow;}{r^R},t^R)\};$

In the following formula; χ { } is the association process algorithm; Mainly comprise: the correlativity to the space peacekeeping time dimension of radiation field is carried out quantitative test; According to the discrimination principle of space-time bidimensional radiation field randomness, with difference target area constantly at random radiation field information be divided into different sets, the information in each set is all done related with corresponding reception scattered field information.Corresponding technology and algorithm commonly used for example are: when adopting electromagnetic field magnitude information, can adopt association algorithms such as matrix is directly inverted, compressed sensing technology; When adopting electromagnetic field field strength information, can adopt association algorithms such as optimization method, statistical correlation and associating statistical correlation.

In addition; Increase gaze duration or irradiation number of times, but the target identification information that is comprised in the scattered field also increase thereupon, through merging repeatedly the information of association process; Be embodied as the lifting of image space resolution, thereby can surmount the microwave staring imaging of traditional antenna aperture space resolution.

The such scheme that the present invention proposes can be used for reaching the observation of staring to bare weight point zone over the ground, and the imaging system of utilizing the present invention to propose can be equipped on the variety carrier such as geosynchronous satellite, hovering platform.

Compare with above-mentioned traditional formation method, the such scheme that the present invention proposes has the following advantages at least: can overcome the defective that traditional real aperture radar spatial resolution depends on antenna aperture, realize high-resolution microwave staring imaging; For traditional staring imaging radar, increase gaze duration and only can increase signal to noise ratio (S/N ratio), but can not improve spatial resolution; And, can pass through to increase gaze duration room for promotion resolution effectively for the such scheme that the present invention proposes.

The such scheme that the present invention proposes through the microwave staring imaging of space-time bidimensional radiation field, overcomes the defective that traditional real aperture radar spatial resolution depends on antenna aperture, realizes high-resolution microwave staring imaging.Space-time bidimensional radiation field

at random provides basic premise for surmounting antenna aperture; Since under the different sample special actinal surface at random radiation obtained the different space of form radiation field at random; Form space-time bidimensional radiation field at random; The radiation field information space stochastic distribution of each irradiation all is different; Each wave beam inscattering field that obtains is also incomplete same, thereby but can obtain a large amount of target identification informations when making radiation field and interacting goals.By demonstrating non-correlation between any different rows that receives the observing matrix that echo constituted and the different lines, guaranteed the necessary condition of target as reconstruct.As long as guarantee that getting irrelevant sequence satisfies the inverting requirement; Can echo in the wave beam be converted into the object space information distribution in zone to be measured through the space-time bidimensional association process of radiation field and scattered field at random, thereby the scattered information that originally is coupled is separated.Through guaranteeing gaze duration, the lifting that can bring spatial resolution realizes surmounting the high-resolution microwave staring imaging in aperture.

Below in conjunction with accompanying drawing the present invention is described in further detail, and the described imaging scheme of utilization front summary of the invention, the form that adopts numerical simulation to give an example has been verified validity of the present invention.

The present invention at first to based on the space at random the high-resolution imaging of the microwave staring imaging of radiation field carry out simulating, verifying; Suppose that traditional real aperture radar beam coverage area is 10m * 10m; Because traditional real aperture radar only depends on beam scanning or the synthetic spatial discrimination that carries out of wave beam, the target in the wave beam is to be difficult to realize differentiating.Therefore to shown in Figure 3 two at a distance of differentiating for the target of 1m; When adopting the formation method of patent of the present invention; Hypothetical target zone radiation field at random is as shown in Figure 3, and the overlay area is 10m * 10m, when gaze duration is sampled as 50 times; Can get the inverting target as as shown in Figure 5; The visual target picture has been able to recover basically, therefore in order to make target more clear, can realize through increasing gaze duration.Target image by inversion when Fig. 6 has provided gaze duration sampling 100 times, the accurately reconstruct of target this moment.

In the time will realizing that resolution as shown in Figure 7 is the target imaging of 0.2m, suppose to adopt the radiation field of target area as shown in Figure 8, when gaze duration sampling 500 times, it is shown in Figure 9 that the inverting target looks like., can further increase gaze duration, when gaze duration sampling 2500 times, it is shown in Figure 10 that the inverting target looks like.It is thus clear that along with the increase of gaze duration, imaging resolution improves gradually, therefore can be through increasing the purpose that gaze duration reaches high-resolution imaging.

For imageable target shown in Figure 11, imaging region is 40m * 40m, under the irradiation of radiation field at random; Target image by inversion under the different gaze durations is respectively Figure 12 (a), 12 (b), 12 (c), this shows, along with the increase of gaze duration; Imaging resolution improves gradually; The target picture is clear gradually, and this and traditional real aperture radar imaging are essentially different, and traditional real aperture radar imaging is to be difficult to differentiate for the target in the wave beam; Increase the raising that gaze duration can not exchange imaging resolution for, so the formation method of this patent is to staring the strong expansion in radar imagery field.

Those skilled in the art are appreciated that and realize that all or part of step that the foregoing description method is carried is to instruct relevant hardware to accomplish through program; Described program can be stored in a kind of computer-readable recording medium; This program comprises one of step or its combination of method embodiment when carrying out.

In addition, each functional unit in each embodiment of the present invention can be integrated in the processing module, also can be that the independent physics in each unit exists, and also can be integrated in the module two or more unit.Above-mentioned integrated module both can adopt the form of hardware to realize, also can adopt the form of software function module to realize.If said integrated module realizes with the form of software function module and during as independently production marketing or use, also can be stored in the computer read/write memory medium.The above-mentioned storage medium of mentioning can be a ROM (read-only memory), disk or CD etc.

The above only is a preferred implementation of the present invention; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; Can also make some improvement and retouching, these improvement and retouching also should be regarded as protection scope of the present invention.

Claims (9)

1. the method for a microwave staring imaging is characterized in that, may further comprise the steps:

The microwave imaging radiate source radiation becomes to have the antenna actinal surface field of extraordinary random distribution characteristic, and radiation is at random carried out in wave beam coverage goal zone, forms when possessing, the radiation field at random of empty bidimensional random distribution characteristic

When its random character shows as, the desirable uncorrelated nature of empty bidimensional; Wherein,

Be any some positions of wave beam coverage goal area planar; Radiation field

After the detected target interaction, form the echo scattered field, receive echo scattered field signal by receiver

Wherein,

Be receiver space position, t ^RBe the time of reception; With the said echo scattered field signal that receives

With target area radiation field at random

When carrying out, empty bidimensional relevance imaging handles, the object space information distribution in reconstruct zone to be measured realizes the microwave staring imaging.

2. the method for microwave staring imaging as claimed in claim 1; It is characterized in that said radiation field at random

is:

$\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t)=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}g({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t)f({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;},$ Wherein

Be antenna actinal surface field t ^TConstantly, the position does

The chopped radiation signal of place's radiation, N is a radiation phase center number, the irradiation area of i radiation signal is S _i',

Be any some positions of wave beam coverage goal area planar, It is the time domain Green function of the free space of i radiation signal.

3. the method for microwave staring imaging as claimed in claim 2; It is characterized in that; Radiation field on any different resolution elements in the wave beam coverage goal zone

has irrelevant characteristic, and its uncorrelated nature is characterized by:

$I({\stackrel{\&RightArrow;}{r}}_1,{\stackrel{\&RightArrow;}{r}}_2,t)=<{\mathrm{\&Psi;}}^{*}({\stackrel{\&RightArrow;}{r}}_1,t)\mathrm{\&Psi;}({\stackrel{\&RightArrow;}{r}}_2,t)>$

$=\underset{t}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}{g}^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_1,t)f^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\&CenterDot;\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}g({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_2,t)f({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\mathrm{dt}$

$=\underset{t}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}\underset{{S_j}^{\&prime;}}{\&Integral;}R({\stackrel{\&RightArrow;}{r}}_i^T,{\stackrel{\&RightArrow;}{r}}_j^T,t^T)\&CenterDot;g^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,{\stackrel{\&RightArrow;}{r}}_1,t)\&CenterDot;g({\stackrel{\&RightArrow;}{r}}_j^T,t^T,{\stackrel{\&RightArrow;}{r}}_2,t)d{S_i}^{\&prime;}d{S_j}^{\&prime;}\mathrm{dt}$

Wherein, <>expression inner product operation,

is the related function of a plurality of radiation phase center radiation signals.

4. the method for microwave staring imaging as claimed in claim 2 is characterized in that, has irrelevant characteristic between the radiation field in the different wave beam coverage goals constantly zone, and its uncorrelated nature is characterized by:

$I(\stackrel{\&RightArrow;}{r},t_1,t_2)=<{\mathrm{\&Psi;}}^{*}(\stackrel{\&RightArrow;}{r},t_1)\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t_2)>$

$=\underset{s^{\&prime;}}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}{g}^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_1)f^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}\&CenterDot;\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}g({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_2)f({\stackrel{\&RightArrow;}{r}}_i^T,t^T)d{S_i}^{\&prime;}d{s}^{\&prime;}.$

$=\underset{s^{\&prime;}}{\&Integral;}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{{S_i}^{\&prime;}}{\&Integral;}\underset{{S_j}^{\&prime;}}{\&Integral;}R({\stackrel{\&RightArrow;}{r}}_i^T,{\stackrel{\&RightArrow;}{r}}_j^T,t^T)\&CenterDot;g^{*}({\stackrel{\&RightArrow;}{r}}_i^T,t^T,\stackrel{\&RightArrow;}{r},t_1)\&CenterDot;g({\stackrel{\&RightArrow;}{r}}_j^T,t^T,\stackrel{\&RightArrow;}{r},t_2)d{S_i}^{\&prime;}d{S_j}^{\&prime;}d{s}^{\&prime;}$

Wherein, <>expression inner product operation,

is the related function of a plurality of radiation phase center radiation signals.

5. the method for microwave staring imaging as claimed in claim 2; It is characterized in that the received echo scattered field of said receiver signal

is:

$u_r(\stackrel{\&RightArrow;}{r^R},t^R)=\underset{S^{\&prime;}}{\&Integral;}\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t)\mathrm{\&sigma;}\left(r\right)g({\stackrel{\&RightArrow;}{r}}^R,t^R,\stackrel{\&RightArrow;}{r},t)d{S}^{\&prime;}$

The receiver space position does

Be t the time of reception ^R, σ (r) is the detection of a target

The backscattering coefficient of position,

Time domain Green function for the free space of RX path.

6. the method for microwave staring imaging as claimed in claim 1 is characterized in that, said scattered field when being constant target scattering characteristics to the time radiation field at random that becomes spatial modulation.

7. the method for microwave staring imaging as claimed in claim 1; It is characterized in that; In order to realize that the target image that lies in the scattered field is carried out inverting and reconstruct, when carrying out with known irrelevant radiation field at random, the processing of empty bidimensional relevance imaging to receiving scattered field:

$\mathrm{\&sigma;}\left(\stackrel{\&RightArrow;}{r}\right)=\mathrm{\&chi;}\{\mathrm{\&Psi;}(\stackrel{\&RightArrow;}{r},t),u_r(\stackrel{\&RightArrow;}{r^R},t^R)\}$

In the following formula, χ { } is the associated images Processing Algorithm.

8. the method for microwave staring imaging as claimed in claim 1; It is characterized in that, increase gaze duration or irradiation number of times, but the target identification information that is comprised in the scattered field increases thereupon also; Through merging repeatedly relevance imaging information processed, be embodied as the lifting of image space resolution.

9. the method for microwave staring imaging as claimed in claim 1 is characterized in that, is applied on geosynchronous satellite or the hovering platform carrier based on the method for the said microwave staring imaging of space-time bidimensional radiation field.

Images