基于稀疏线阵的机载合成孔径雷达成像模型、方法与实验研究.docx

基于稀疏线阵的机载合成孔径雷达成像模型、方法与实验研究
Introduction:
Syntheticapertureradar(SAR)iswidelyusedinmanyfields,includingearthobservation,agriculture,military,andsoon.SARcanprovidehigh-resolutionimagesregardlessofweatherconditionsandtimeofday.However,theSARimagingalgorithmrequiresalargeamountofcomputationalresourcesandlongacquisitiontime.Toovercomethisproblem,sparselineararray-basedairbornesyntheticapertureradar(SAR)hasbeenproposed.Inthispaper,weproposeasparselineararray-basedairbornesyntheticapertureradarimagingmodel,amethod,andexperimentalstudies.
Sparselineararray-basedSARImagingModel:
TheproposedSARimagingmodelconsistsofthreemainparts:1)signalmodel,2)motioncorrectionmodel,and3)imagingalgorithm.
1.Thesignalmodeldescribesthereflectedsignalfromthetargetsceneasfollows:
y(t)=∑i=1NS(ti-τi)ej(φi+ψi)+n(t)
Wherey(t)isthereceivedsignal,Nisthenumberofscatterers,S(ti-τi)isthesignalreceivedfromtheithscatterer,τiisthetimedelayoftheithscatterer,φiisthephaseoftheithscatterer,ψirepresentstheDopplershiftoftheithscatterer,andn(t)istheGaussiannoise.
2.Themotioncorrectionmodelcorrectsthephasedistortioncausedbytheaircraft'smotionduringdataacquisition.Themotioncorrectioncanbeformulatedas:
y(mc)(t)=y(t)ej2πfc(t-ta)
Wherey(mc)isthesignalaftermotioncorrection,fcisthecarrierfrequency,andtaisthetimedelaycausedbytheaircraft'smotion.
3.Theimagingalgorithmusesthemotion-correctedsignaltogeneratetheSARimage.Thealgorithmcanbeformulatedas:
I(x,y)=∑i=1M∑j=1Ny(mc)(t)g(t-t0)g(t-t0-τij)e-j2πfct0e-j2πfxiτije-j2πfyjτij
WhereI(x,y)istheSARimage,Misthenumberofrangecells,Nisthenumberofazimuthcells,τijisthetimedelaybetweentheithscattererandthejthelementofthelineararray,t0isthereferencetime,g(t)isthepulsetransmissionfunction,fcisthecarrierfrequency,xiandyiarethepositionsofthejthelementintherangeandazimuthdirection,respectively.
Sparselineararray-basedSARimagingMethod:
TheproposedSARimagingmethodincludesthefollowingsteps:
1.Dataacquisition:TheSARsystemacquiresthedatafromthetargetsceneusingasparselineararray-basedradar.
2.Moti