The Radar Imaging Based On Space Spectrum And Temporal-Spatial Stochastic Radiation Field

Recent distributed radar has natural space launch characteristics, and it can reconstruct targetusing spatial diversity and frequency diversity joint effect, so it provides a new means of acquiringinformation for high resolution target inversion and cognitive. Then the space spectrum theory isdistributed the important tool of imaging performance analysis, and the combination of both couldgive immediate inspiration and guidance for the distributed imaging principle characterization andthe new imaging method. However in application, this kind of space launch of multi-input andmulti-output form of distributed radar imaging causes the implementation complexity. Thus,seeking a new microwave imaging mechanism, which is not dependent on space launchcharacteristics and relative motion conditions and can breakthrough antenna aperture restrictions,will bring potential application value. Such an attempt may open a new way for key area gazeobservation of specific situations. Therefore, this paper studies that revolves around the proposednew method of distributed imaging and new mechanism of microwave staring imaging.The SAR obtains vertical and horizontal resolution through different means, where thedistance high resolution ability is by wideband signal and the azimuth high resolution ability is byradar strict movement. Whether an imaging approach exists that could complete the unrestrictedconfiguration two dimensional target imaging adopting a method, and the distributed radar systemhas natural space launch characteristics that can achieve the goal. Secondly, The Fourier transformrelations exists between distributed radar multi-channel observation sample and target catteringfunction, which is the theoretical basis of the distributed imaging. spatial diversity and frequencydiversity joint effect is used, and the progressive research of effective imaging methods from thenon-uniform configuration to any configuration. Then the space spectrum filling and distributedradar imaging method is combined to provide a convenient tool for the new imaging method r andperformance analysis.The way of staring high resolution target imaging imaging exists through a single sensor willbe a very worthy exploration and research direction. The traditional radar obtains target imagingby the matching of scattering echo and template signal, and the target in the beam is unable torealize distinguish. Whether starting from the field domain shows a possible new ideas for thehigh resolution imaging of staring radar, which means that the target information could be byspace association between the radiation field formed special distribution of the airspace andscattering echo. The target redundant information is obtained effectively unless this specialdistribution radiation field must include more information than traditional beam field when interacting with target. Only the differences distribution of radiation field in both time domain andairspace can meet the requirements, and its ideal model is the temporal-spatial stochastic radiationfield field put forward in this paper. At this time, the scattering field is the constant target's spacemodulation of time-varying random radiation field. The identified target's spatial distributioninformation is contained within the scattering field in proportion to space-time change, so theresult of association brings the spatial resolution improving significantly , which means that theimaging method is feasible based on the temporal-spatial stochastic radiation field.Based on the above about staring imaging and distributed imaging problems and solution: 1.The new concept of time-space random radiation field is put forward. Analysis shows that theradiation field statistical characteristics play key roles for targe inversion. Then high resolutionimaging mechanism based on random radiation field is expounded from simulation contrast withthe traditional real aperture imaging method, The feasibility analysis of temporal-spatial stochasticradiation field to relize the actual scene approximation using gabor expansion.Then themathematical model of radom aperture-field is established, and the analytical calculation fromradom aperture-field to random radiation field is completed. It shows that the particularcombination of discrete point-source could from any radom aperture-field, which has importantreference value conclusion for system design. 2. The space spectrum imaging principle of thedistributed radar is finished. Research shows that the imaging resolution contribution is obtainedby the comprehensive effect of the space characteristic and the signal characteristics (nonlinearcoupling relationship), which means that the space launch function and signal bandwidth rolecould form good complementary relationship, and this is very important for narrow-banddistributed imaging system. 3. A novel robust imaging method called point-wise matched filterand the Non-Uniform Fast Fourier Transform(NUFFT) imaging methodis are proposed, whichadapts to non-uniform space spectrum filling, thus the strengthen imaging method is practical.Then the improved target detection methods is given to improve the detection performance ofsingle radar.4. A novel sparse radar imaging method is proposed for extreme and sparseconfiguration, and it fully takes advantage of the compressive sensing in signal recovery based onsparse and random sampling, which has a natural applicability for this kind of typical scene andhas the ability of super-resolution, so it can directly change the weakness such as irregularconfiguration of distributed radar to advantages of high resolution imaging.