简介:Thegenerationofhigh-resolutionDEMfrominterferometricSARhasresultedintheneedforaccurateandefficientmethodsof2-dimensionalphaseunwrapping.Inthispaper,wegiveabriefdescriptionofthemathematicalbaseofphaseunwrapping,andadetaileddescriptionoftheunweightedandweightedleastsquarephaseunwrappingalgorithm.Thenouralgorithmcombiningwiththeweightedleastsquarephaseunwrappingguidedbythebranch-cutsderivedfromGoldstein’salgorithmandcoherencecoefficientmapderivedfromtheINSARdataisprovided.InourexperimentwewritesubroutinesoftheGoldstein’sbranch-cutalgorithm,unweightedandweightedleastsquarephaseunwrappingalgorithmaswellasouralgorithm,andconstructasmallexperimentsystemtoresolvethephaseunwrappingproblem.FinallywetestouralgorithmonsomeINSARdata.Theresultshowsthatourapproachcanobtainunwrappedphasecorrectlyandefficiently.
简介:DuetothedifferentsignalfrequenciesfortheGLONASSsatellites,thecommonly-useddouble-differencingprocedureforcarrierphasedataprocessingcannotbeimplementedinitsstraightforwardform,asinthecaseofGPS.Inthispaperanoveldataprocessingstrategy,involvingathree-stepprocedure,forintegratedGPS/GLONASSpositioningisproposed.Thefirstispseudo-range-basedpositioning,thatusesdouble-differenced(DD)GPSpseudo-rangeandsingle-differenced(SD)GLONASSpseudo-rangemeasurementstoderivetheinitialpositionandreceiverclockbias.ThesecondisformingDDmeasurements(expressedincycles)inordertoestimatetheambiguities,byusingthereceiverclockbiasestimatedintheabovestep.ThethirdistoformDDmeasurements(expressedinmetricunits)withtheunknownSDintegerambiguityfortheGLONASSreferencesatelliteastheonlyparameter(whichisconstantbeforeacycleslipoccursforthissatellite).Areal-timestochasticmodelestimatedbyresidualseriesoverpreviousepochsisproposedforintegratedGPS/GLONASScarrierphaseandpseudo-rangedataprocessing.Otherassociatedissues,suchascycleslipdetection,validationcriteriaandadaptiveprocedure(s)forambiguityresolution,isalsodiscussed.Theperformanceofthisdataprocessingstrategywillbedemonstratedthroughcasestudyexamplesofrapidstaticpositioningandkinematicpositioning.Fromfourexperimentscarriedouttodate,theresultsindicatethatrapidstaticpositioningrequires1minuteofsinglefrequencyGPS/GLONASSdatafor100%positioningsuccessrate.Thesingleepochpositioningsolutionforkinematicpositioningcanachieve94.6%successrateovershortbaselines(<6km).