GPS在區(qū)域地面沉降監(jiān)測(cè)中的應(yīng)用AbstractTheGlobalPositioningSystem(GPS)hasbecomeanincreasinglypopulartoolingeodeticmonitoringanddisplacementmeasurements.OneofthemostnoteworthyapplicationsofGPSisitsuseinregionalgroundsubsidencemonitoring.Groundsubsidenceisaphenomenonthatcancauseconsiderabledamagetoinfrastructure,includingbuildings,roads,bridges,andpipelines.TheaccuracyandprecisionofGPSmeasurementsmakeitanidealtoolforthedetectionofmillimeter-levelsubsidence.ThispaperexaminestheapplicationofGPSinregionalgroundsubsidencemonitoring,discussingthetheory,operationalprinciples,andpracticalconsiderationsofusingGPSinthiscontext.Furthermore,thepaperanalysestheadvantagesanddisadvantagesofGPSincomparisonwithotheravailablemethodsusedingroundsubsidencemonitoring.IntroductionGroundsubsidencehappenswhenthereisadeclineingroundsurfaceelevationovertime.Itcanoccurduetovariousreasons,includingtheremovalofundergroundwater,oil,orgas,theweakeningofundergroundgeostructures,andthedissolutionofundergroundcavities.Groundsubsidenceposesasignificantthreattoinfrastructure,alteringthegroundsurfaceprofileandeventuallycausingdamagetoproperties,structures,andutilities.Therefore,monitoringgroundsubsidenceisessentialtomitigatethedamagecaused.Thetraditionaltechniquesusedforgroundsubsidencemonitoringarespiritleveling,opticaltransits,andInSAR.However,thesetechniqueshavelimitationsontheiraccuracy,frequency,andspatialcoverage.Therefore,theymaynotbeabletoprovidesufficientdataforanaccurateandcomprehensiveinterpretationofgroundsubsidence.GPS,ontheotherhand,offershighprecisionandaccuracyinmeasurements,makingitanidealtoolforgroundsubsidencemonitoring.GPSiscapableofdetectingmillimeter-levelmovement,makingithighlysensitivetosmallchangesinelevation.Furthermore,GPScancoverabroadareawithcontinuousmonitoring,thusprovidingextensivespatialcoverageofgroundsubsidence.OperationalPrinciplesofGPSinGroundSubsidenceMonitoringGPSmeasuresthedistancesbetweentheGPSreceiversstationedatdifferentlocationsonthegroundsurface.ItcalculatesthedistancesbetweentheGPSreceiversthroughthemeasurementofthetimedelayofradiosignalstransmittedbyGPSsatellites.Fromthesemeasurements,GPSsoftwarecandeterminethepreciselocationofeachreceiver,whichreflectstherelativeverticalandhorizontalmotionsbetweenthereceivers.TheGPSmeasurementofgroundsubsidencerequirestheuseofatleasttwoGPSreceiverslocatedatdifferentspotsonthegroundsurface.TheGPSreceiversrecordthechangesintheirrelativepositionsovertime,andfromthesechanges,theextentanddirectionofgroundsubsidencecanbedetected.TheoryofGPSinGroundSubsidenceMonitoringGPSdisplacementmeasurementsarerelatedtothewavelengthoftheGPScarrierphase.ThecarrierphaseisthewavepartoftheGPSsignalthatdeterminesthetimedelaybetweenthetransmissionandreceptionoftheGPSsignal.ThewavelengthoftheGPScarrierphaseisapproximately20cm,whichisshorterthanthewavelengthsofotherelectromagneticwaves,suchasradioandtelevisionwaves.TheshortwavelengthoftheGPScarrierphasemakesitsensitivetosmallchangesinthedistancebetweenGPSreceivers.Furthermore,thephasedifferencebetweensignalsreceivedatdifferentGPSreceiverscanbemeasuredwithgreatprecision,enablingtheestimationofgroundsubsidencetowithinmillimeter-levelaccuracy.PracticalConsiderationsofGPSinGroundSubsidenceMonitoringThesuccessfulapplicationofGPSinmonitoringgroundsubsidencerequiresseveralpracticalconsiderations.Amongthem,themostsignificantistheproperinstallationanddeploymentofGPSreceivers.Thereceiversmustbemountedsecurelyandaccuratelytoensuretheirstabilityandprecision.Additionally,thereceiversshouldnotbeplacednearmetallicobjects,whichcaninterferewiththereceptionofGPSsignals.Furthermore,thefrequencyofGPSmeasurementsiscrucialinmonitoringgroundsubsidence.GPSmeasurementsshouldbemadefrequentlytodetectsmallchangesinelevation,withastandardsamplingintervalof30secondsbeingrecommended.TheGPSdatamustbestoredinasecurelocationandanalyzedassoonaspossibletominimizedatalossandensuretheeffectiveinterpretationofgroundsubsidence.AdvantagesandDisadvantagesofGPSinGroundSubsidenceMonitoringTheadvantagesofusingGPSingroundsubsidencemonitoringincludeitsabilitytodetectmillimeter-levelsubsidence,coveralargespatialdomain,andcontinuousmonitoring.ThehighaccuracyandprecisionofGPSmeasurementsenablethedetectionofsmallmotions,whichcanbeusedtoidentifytheonsetofsubsidence.GPScanalsobesetuptorecorddatacontinuously,withouttheneedformanualintervention,thusfacilitatingthecaptureoftemporalandspatialvariationsinsubsidence.However,GPShassomelimitationsingroundsubsidencemonitoring.Firstly,thecostoftheGPSequipmentanditsmaintenancecanmakeitexpensivetodeployandmaintain,limitingitswide-scaleapplications.Secondly,GPSmeasurementscanbeaffectedbyweatherconditions,includingcloudsandrain,whichcanreduceGPS’saccuracyandprecision.ConclusionTheuseofGPSinregionalgroundsubsidence