简介：Selfscanningphotodiodearray(SSPA)isakindofsolidstateimagingsensor.ThesignalprocessingmethodusingaspecialsectorSSPAwasinvestigated.BasedontheprincipleandcharacteristicsofSSPA,asignalacquisitionandprocessingmethodcontrolledbycomputerwasintroduced.Theamplificationofweaksignal,thematchingoftimesequence,thefastpeakholdingwithlowleakage,thehighspeedA/Dconversionandnonlinearcorrectionwerediscussed.ThismethodcanacquirethepeaksignalofeveryringofsectorSSPAwithhighaccuracyandinrealtime.Itcanbeusedtodetectthedistributionofspacelightenergy.

简介：Amodifiednon-coherentsequentialdetectiondecisionlogicbasedoncontinuousaccumulationtoachievefastPNcodeacquisitionisproposed.Tosimplifythedesignandanalysis,theequivalentrelationshipbetweenthelikelihoodratioofthecurrentsampleandthatofalltheprevioussamplesisdeduced.Theschemeisprovedtobeanoptimumsequentialdetectionundercertainassumptions.Becausetheaveragesamplenumber(ASN)cannotbecalculatedthroughthemethodsappliedtotheconventionalsequentialdetection,analgorithmisalsoprovided,whichcanestimateboththeprobabilitydensityfunction(pdf)andtheupperthresholeofASN.Thedesiredprobabilitiesoffalsealarmanddetection,aswellasfasterPNcodeacquisitioncomparedtotheconventionalsequentialdetectioncanbeachievedbyemployingthisstructure.Inaddition,Rayeigh-fadedreceptioncaseisalsotakenintoconsideration.Performancesoftheproposedschemesareobtained,whichsuggestthattheproposednon-coherentsequentialdetectionismoredesirable.

简介：Anideaofestimatingthedirectsequencespreadspectrum(DSSS)signalpseudo-noise(PN)sequenceispresented.WithouttheapriorityknowledgeabouttheDSSSsignalinthenon-cooperationcondition,weproposeaself-organizingfeaturemap(SOFM)neuralnetworkalgorithmtodetectandidentifythePNsequence.Anon-supervisedlearningalgorithmisproposedaccordingtheKohonenruleinSOFM.TheblindalgorithmcanalsoestimatethePNsequenceinalowsignal-to-noise(SNR)andcomputersimulationdemonstratesthatthealgorithmiseffective.Comparedwiththetraditionalcorrelationalgorithmbasedonslip-correlation,theproposedalgorithm’sbiterrorrate(BER)andcomplexityarelower.

简介：Thestudyontheacquisitionandtrackingsimulationsysteminsatellite-groundopticalcommunicationsispresentedhere.Byapplyingglobalpositioningsystem(GPS)coordinatecalculation,thetimeneededininitialacquisitionoflightbeaconcanbereducedlargely.Smithpredictorisappliedtocompensatethemechanicalhysteresisoftrackingsystemandtoimprovethedynamicperformanceofthesystem.Trackingexperimentsovera16kmdistanceonthegroundareconductedtoverifythetrackingoflightbeaconinsatellite-groundopticalcommunications.Thestandarddeviationofhorizontalcoordinatesis35.3568μradandthemaximumoffsetis209.3675μradinstabletracking.