简介:Bistaticforward-lookingsyntheticapertureradar(SAR)hasmanyadvantagesandapplicationsowingtoitstwodimensionalimagingcapability.Therecouldbevariousimagingconfigurationsbecauseofthegeometricflexibilityofbistaticplatforms,resultinginkindsofmodelsbuiltindependentlyamongwhichtherecouldbesomesimilareventhesamemotionfeatures.Comprehensiveresearchonsuchsystemsinamorecomprehensiveandgeneralpointofviewisrequiredtoaddresstheirdifferenceandconsistency.PropertyanalysisofbistaticforwardlookingSARwitharbitrarygeometryisachievedincludingstripmapandspotlightmodesonairborneplatform,missile-borneplatform,andhybridplatformofboth.Emphasisisplacedonazimuthspacevarianceofsomekeyparameterssignificantlyaffectingthesubsequentimagingprocessing,basedonwhichthefrequencyspectraarefurtherdescribedandcomparedconsideringrespectivefeaturesofdifferentplatformsforfrequencyimagingalgorithmdeveloping.Simulationresultsconfirmtheeffectivenessandcorrectnessofouranalysis.
简介:Inthespaceborne/airborneforward-lookingbistaticsyntheticapertureradar(SA-FBSAR),duetothesystemplatforms'remarkablevelocitydifferenceandtheforward-lookingmode,therangecellmigration(RCM)notonlydependsonthetarget'stwodimensionallocation,butalsovarieswiththerangelocationnonlinearly.Andthenonlinearityisnotjusttheslightdeviationfromthelinearpart,butexhibitsevidentnonlineardepartureintheRCMtrajectory.IftheRCMisnotproperlycorrected,nonlinearimagedistortionswouldoccur.BasedontheRCMmodel,amodifiedtwo-stepRCMcompensation(RCMC)methodforSA-FBSARisproposed.Inthismethod,firstlytheazimuth-dependentRCMiscompensatedbythescalingFouriertransformandthephasemultiplication.Andthentherange-dependentRCMisremovedthroughinterpolation.TheeffectivenessoftheproposedRCMCmethodisverifiedbythesimulationresultsofbothpointscatterersandareatargets.