标签: synthetic

SARSyntheticApertureRadarSheet1of18SARSyntheticApertureRadarWhyusemicrowavefrequencies?-atmosphericattenuationislowatmicrowavefrequencies,particularly1-10GHz,apartfromresonancesduetooxygenandwatermolecules.-microwavesignalswillpenetratecloudandfog,incontrasttovisibleradiation.-microwavescancontinuouslymonitorploarregionsandtropicalforeststhatareoftenindarknessorcoveredinclouds.-SARistobeusedtomonitornaturaldisasters-floods,forestfires,earthquakesetcthatareoftenaccompaniedbypooropticalvisibility.-fairlynarrowbeamscanbeobtainedwithresonablysizedantennastogiveacceptableresolution.FeaturesofSAR-alargeeffectiveantennaapertureisobtainedbymountingtheantennaonamovingplatform-anaircraftorasatellite.-reso……