introduction to and basics of processing with...

IntroductiontoandbasicsofprocessingwithTRACK

M.A.FloydMassachusettsInstituteofTechnology,Cambridge,MA,USA

SchoolofEarthSciences,UniversityofBristolUnitedKingdom2–5May2017

MaterialfromT.A.Herring,R.W.King,M.A.Floyd(MIT)andS.C.McClusky (nowANU)

http://web.mit.edu/mfloyd/www/courses/gg/201705_Bristol/

KinematicGPS• ThestyleofGPSdatacollectionandprocessingsuggeststhat

oneormoreGPSstationsismoving(e.g.,car,aircraft)• Toobtaingoodresultsforpositioningasafunctionoftimeit

helpsiftheambiguitiescanbefixedtointegervalues.Althoughwiththe“backsmooth”optionintrackthisisnotsocritical.

• ProgramtrackistheMITimplementationofthisstyleofprocessing.TherealtimeversionistrackRT and trackRTB

• Unlikemanyprogramsofthistype,trackpre-readsalldatabeforeprocessing.(Thisapproachhasitsprosandcons)

2017/05/04 TrackKinematic 1

Generalaspects• Thesuccessofkinematicprocessingdependsonseparationof

sites• Ifthereareoneormorestaticbasestationsandthemoving

receiversarepositionedrelativetothese.• Forseparations<10km,usuallyeasy• 10>100kmmoredifficultbutoftensuccessful• >100kmverymixedresultsdependingonqualityofdata

collected.


Slowmovingsites• Forslowmovingsites(glaciers,earlylandslides),gamit solutioncan

bemoreeasilyautomatedthantracksolutionsandcangeneratehighqualityresultsespeciallyifmotionisnearlylinear(withhighrates100m/yr forexample).

• Withgamit solutions:– Putbestestimateofvelocityintheaprioricoordinatefileusedin

gamit (positionestimatewillbethemeanoffsetfromthislinearmodel).

– Usesh_gamit with–sessinfo optiontohavemultiplesolutionsbeday(setstarttimeanddurationofeachsessione.g.,83-hrsessionsperday;36030-secepochspersession).Use–netext optiontoputeachsessionindifferentdirectory(-noftp afterfirstsessionalsospeedsuprunifsitesmissing).

– Sometuningofminxf inprocess.defaults andreducevaluesintrim_oneway_tol inautcln.cmd sothatsmalldatasetsarenotremoved.

• Trackcanalsobeusedforthesetypesofanalyses


Issueswithlength• Assiteseparationincreases,thedifferentialionosphericdelaysincreases,atmosphericdelaydifferencesalsoincrease

• Forshortbaselines(<2-3km),ionosphericdelaycanbetreatedas~zeroandL1andL2ambiguitiesresolvedseparately.PositioningcanuseL1andL2separately(lessrandomnoise).

• ForlongerbaselinesthisisnolongertrueandtrackusestheMW-WLtoresolveL1-L2cycles

• IONEXfilescannowbeincludedtohelpwiththeionosphericdelayonlongbaselines.


Trackfeatures• TrackusestheMelbourne-Wubbena WideLane(MW-WL)to

resolveL1-L2andthenacombinationoftechniquestodetermineL1andL2cyclesseparately.

• “Biasflags”areaddedattimesofcycleslipsandtheambiguityresolutiontriestoresolvethesetointegervalues.

• TrackusesfloatingpointestimatewithLC,MW-WLandionosphericdelayconstraintstodeterminetheintegerbiasesandthereliabilitywithwhichtheyaredetermined.

• Kalman filtersmoothingcanbeused.(Non-resolvedambiguityparametersareconstant,andatmosphericdelaysareconsistentwithprocessnoise).Whenatmosphericdelaysareestimated,thesmoothingoptionshouldalwaysbeused.


Ambiguityresolution• Algorithmis“relative-rank”approach.Chi-squaredincrement

ofmakingL1andL2ambiguitiesintegervaluesforthebestchoiceandnextbestarecompared.Ifbesthasmuchsmallerchi-squaredimpact,thenambiguityisfixedtointegervalues.

• Testisoninverse-ratioofchi-squaredincrements(i.e.,Largerelativerank(RR)isgood).

• Chi-squaredcomputedfrom:– MatchofLCcombinationtoestimatedvalue(LC)– MatchtoMW-WLaveragevalue(WL)– Closenessofionosphericdelaytozero(lessweightonlonger

baselines)(LG)• RelativeweightsofLC,WLandLGcanbeset.• Estimatesareiterateduntilnomoreambiguitiescanbe

resolved.


BasicGPSphaseandrangeequations

• Basicequationsshowtherelationshipbetweenpseudorangeandphasemeasurements


!!!!

€

φ1i

k= γ i

k /λ1 − Iik /λ1 +N1i

k+v1i

k

φ2 i

k= γ i

k /λ2 − Iik /λ2

f1f2

&

' (

)

* +

2

+N2 i

k+v2 i

k

R1ik

= γ ik + Ii

k +w1i

k

R2 ik

= γ ik + Ii

k f1f2

&

' (

)

* +

2

+w2 i

k !!!!

€

γ!is!range,!

I!is!ionospheric!delay

λ!is!wavelength

v!and!w!are!noise!

L1-L2andMelbourne-WubbenaWideLane

• ThedifferencebetweenL1andL2phasewiththeL2phasescaledtotheL1wavelengthisoftencalledsimplythewidelane andusedtodetectcycleslips.Howeveritiseffectedbyfluctuationsintheionosphericdelay,whichisinverselyproportionaltofrequencysquared.

• ThelowerfrequencyL2hasalargercontributionthanthehigherfrequencyL1

• TheMW-WLremovesboththeeffectsontheionosphericdelayandchangesinrangebyusingtherangemeasurementstoestimatethedifferenceinphasebetweenL1andL2


MW-WLCharacteristics• Inone-wayform,asshowninnextslide,theMW-WLdoes

notneedtobeanintegerorconstant• Slopeinone-wayiscommon,butnoticethatbothsatellites

showthesameslope.• Ifsamesatellite-pairdifferencefromanotherstation

(especiallywhensamebrandreceiverandantenna)aresubtractedfromtheseresultsthenwouldbeaninteger(evenatthisonestation,differenceisclosetointeger)

• TheMW-WLtellsyouthedifferencebetweentheL1andL2cycles.TogettheindividualcyclesatL1andL2weneedanothertechnique.

• ThereisaformulathatgivesL1+L2cyclesbutithas10timesthenoiseoftherangedataandgenerallyisnotused.


Melbourne-WubenaWideLane(MW-WL)

• EquationfortheMW-WL.ThetermRf/caretherangeincycles(noticethesumduetochangeofsignionosphericdelay)

• TheDf/SftermforGPSis~0.124whichmeansrangenoiseisreducedbyaaboutafactoroften.

• TheML-WLshouldbeinteger(withinnoise)whendatafromdifferentsitesandsatellites(doubledifferences)areused.

• However,receiver/satellitedependentbiasesneedtobeaccountedfor(andkeptuptodate)[tables/dcb.dat].


!!!!

€

mw−wl= φ1 −φ2 −( f1 − f2)

( f1 + f2)R1 f1 /c +R2 f2 /c[ ]

ExampleMW-WLPRN07andPRN28)

-23578705

-23578704

-23578703

-23578702

-23578701

-23578700

-23578699

-23578698

-23578697

-24380372

-24380371

-24380370

-24380369

-24380368

-24380367

-24380366

-24380365

-24380364

19.0 20.0 21.0 22.0 23.0 24.0

etab.07

MW_WL_07_cycles MW_WL_28_cycles

MW_W

L_07_cycles MW_W

L_28_cycles

Time_Hrs


EX-WLExtra-Wide-lane• TheothermeasureofthedifferenceincyclesbetweenL1andL2usedbytrackistheEX-WL(ExtraWidelane).

• Thismeasureisindependentofgeometrybutisaffectedbytheionosphericdelays.OnshortseparationsthismeasureisoftenmorerobustthantheMW-WL.

• Whenwelookattrackbiasfixingnotethata1L1andL2slip(1/1slip)changestheEX-WLbyonly0.28cycles(53mm).(Thisisjust82mmofL1ionosphericdelay,0.5TECU)

!!!!

€

EX −WL = φ1 −φ2

λ2λ1

;λ2λ1

=1.28


Basic Inputsfortrack.• Trackrunsusingacommandfile• Thebaseinputsneededare:– Obs_file specifiesnamesofrinex datafiles.SitescanbeKkinematicorFfixed

– Nav_file orbitfileeitherbroadcastephemerisfileorsp3file

– Modeair/short/long-- Modecommandisnotstrictlyneededbutitsetsdefaultsforvarietyofsituations

– Normallyback_type smoothwouldalsobespecified.• Normallystartwithjustthesecommandsandseehowtherunlooksandbasedonthisoutputstarttuningtrack.


Basicuse• Recommendedtostartwithabovecommandsandseehowthesolutionlooks• Usage:track-ftrack.cmd >&!track.out• Basicqualitychecks:• egrep ‘^PRMS|TYPE’onsummaryfileortrackout(RMSbyPRNinmm)TYPE Site DT ALL 02 05 08 10 15 21 26 29PRMS usn3 LC 7.0 9.4 3.6 10.5 7.9 7.5 7.2 3.9 3.5TYPE Site DT ALL 02 05 08 15 21 26 29PRMS mitb LC 7.2 8.3 3.7 11.0 6.5 8.4 3.6 4.5TYPE Site DT ALL 02 05 08 15 21 26 29PRMS rovr LC 7.4 7.8 4.3 12.5 6.8 8.5 4.4 4.5

• grep Kinematictrack.out |head-<numberofsites>TRACK Version 1.27 GPS Kinematic trajectory program

Kinematic site usn3 appears static Coordinate RMS XYZ 1.84 2.81 2.23 m, Apriori coordinates good: Diff XYZ -0.25 0.74 -0.17 mKinematic site mitb appears static Coordinate RMS XYZ 0.95 1.46 1.11 m, Apriori coordinates good: Diff XYZ 0.93 -1.77 1.70 mKinematic site rovr appears dynamic Coordinate RMS XYZ 17.84 18.26 17.40 m.

• Themessageisrepeatedduringtherun(thustheheadabove)buttheRMSpositiondropsto0.00fornon-kinematicsites.ThisisapseudorangesolutionsoRMSwillbehigh.Makesuresitebehavethewayyouthinktheyshould.

• Checktrack.sum fileforambiguitystatusandRMSscatterofresiduals.


Trackcommandline%track-f <commandfile>-a<ambiguityfile>-d <day>-w <week>-s <S01>

<S02>..<S10>

where<commandfile>isarequiredfilecontainingalistofcommandstocontroltheprogram(seebelow)

<ambiguityfile>isanoptionalfilecontainingamodifiedsetofintegerbiasparametersandsettings(seefulldescriptionbelow).

<day>thestringinthisargumentreplaces<day>inthecommandfilelines(e.g.,bas1<day>0.03owillbecomebas12220.03oifthe-d 222optionisgiven.

<week>thestringherewillreplaceany<week>stringsinthecommandfile(usefulforthenav_file namewhichcouldbeaweekof concatenatedsp3files.

<S01>,<S02>..<S10>are upto10stringsthatcanbereplacedinthecommandfilei.e.thestring<S01>inthecommandfilewillbereplacedbythefirststring,<S02>bythesecondandsoon.Ifonethestringsiscalledspace(alllowercase),thecorresponding<SXX>entrywillbereplacedbyablankcharacter(Thisprovidesameanstoun-commentlines)


Basicuse:Thingstocheck

• Checkonnumberofambiguities(biases)fixed– grep FINAL<summaryfile>

• A3incolumn“Fixd”meansfixed,1meansstillfloatingpointestimate

• Ifstillnon-fixedbiasesoratmosphericdelaysareestimatedthensmoothingsolutionshouldbemade(back_type smooth)

• outputinNEU,geodetic,DHU,XYZcoordinates.NEUaresimpleNorthEastdistancesandheightdifferencesfromfixedsite.(Convenientforplottingandsmallpositionchanges).DHUissimilarbutdifferencearefromtheaprioricoordinatesofthesite.


Moreadvancedfeatures

• Trackhasalargehelpfilewhichexplainsstrategiesforusingtheprogram,commandsavailableandanexplanationoftheoutputandhowtointerpretit.

• Itispossibletoreadasetofambiguitiesin.–WorksbyrunningtrackandextractingFINALlinesintoanambiguityfile.Setting7fortheFixdcolumnwillforcefixtheambiguity.ambiguityfileisthenreadintotrack(-aoptionorambin_file)


Advancedfeatures

• Commandsallowcontrolofhowthebiasesarefixedandeditingcriteriafordata

• Editingistrickybecauseonmovingplatform,jumpsinphasecouldsimplybemovement

• IonosphericdelayandMW-WLusedforediting.

• Explicitedit_svs command• Explicitaddandremovebiasflags


MainTunablecommands• BF_SET<Maxgap><Mingood>

– Setssizesofgapsindatathatwillautomaticallyaddbiasflagforpossiblecycleslip.Defaultis1,buthighratedataoftenmissesmeasurements.

• ION_STATS<Jump>– Sizeofjumpinionosphericdelaythatwillbeflaggedascycleslip.Can

beincreasedfornoisydata• FLOAT_TYPE<Start><Decimation><Type><Floatsigma

Limits(2)><WL_Fact><Ion_fact><MAX_Fit><RR>– Maincontrolonresolvingambiguities.Floatsigmalimits(forLCand

WL)oftenneedresettingbasedondataquality.– <WL_Fact><Ion_fact>controlrelativeweightsofWLandLGchi-

squaredcontributions.– RRisrelativeranktolerance

• Fcodeinoutputisdiagnosticofwhybiasesarenotresolved.


Othercommoncommands• USR_ADDBF<site><prn#><time(ymdhms)>Allowsusertoaddabiasfileatsite<site>forPRN<prn#>at

time<time>.Firstvalidmeasurementatoraftertimewillbeflags.

• USR_DELBF<site><prn#><time(ymdhms)>Allowsusertodeleteabiasfileatsite<site>forPRN<prn#>at

time<time>.Thetimemustmatchwithin50%ofsamplinginterval.


TrackOutputFiles• Trackoutputsprogressdirectlytothescreenandthisoutput

canbere-directedwith>toafile.(Generallytrack_xxx.out)• Summaryfile(track.sum bydefault)• Positionfiles(NEU,GEOD,DHU,XYZ)• Phaseresidualfiles(optional)• Wide-lanevaluefiles:(optional,sometimeusefulifcycleslip

missed)• Meaningofoutputentriesdiscussedinhelpfile.


Summaryfile

• Thisfileisashortsummaryoftherun.Itlists– filesandparametersthatwereusedfortherun– Processnoisevalues– Anyeditingspecifiedbytheuser– FINALbiasflagreport.TheFixdcolumnindicatesifthebiaswasfixed(denotedbyvalue3).

– Summaryofresidualscatterasfunctionofsiteandsatelliteandversuselevationangle(TheseareRMSdifferencesfromfixedstation)• GenerallyresidualRMSshouldbelessthan10mmalthoughvaluesupto20mmcanbeOK.


Outputfilefromtrack• Trackoutputsextensiveinformationduringitsrun.– Theinitialoutputisstatusduringreadingoftherinexfiles.Errorsinthefilesarereportedhereandasummaryofsatellitesseen.• Mostcommonproblemhereisnosamplingrategiveninrinex file.CommandINTERVALneedstobeused.

– AninitialpseudorangesolutionestablishesthetrajectoryofthekinematicsitesandstatisticsondifferencesfromaprioricoordinatesandRMSscatteroftrajectoryaregiven.

– Biasflagsbeingadded duetojumpsinwide-lanesarereported.

– BadaprioricoordinatescanleadtoBADPREFITdata(seesite_pos)


Outputcontinued• SummaryofBiasflagsneededwithestimatesofnumbersof

cycles.Thesearereportedbysite,satelliteandepochrange.Initialsetare labeledINITIAL.

• EstimatesofmeanMW-WLandMeanIonosphericdelay (EX-WL)alongwithsigmaestimatesaregiven.(Acorrelationtimeisassumedinthesigmacalculation).

• Dependencesofbiasesaregivenwiththe‘DDbiasrefs’entries.Althoughlistedasoneways,valuesaredoubledifferences.


Outputcontinued• Iteratively,tracktriestoresolvetheambiguitiestointeger

values.– Floatingpointestimatesofthebiasesastheyareestimated.– RMSfitofthedoubledifferenceresiduals– Anybaddoubledifferencesarereportedandremoved(repeating

valuescanbeindicationofmissedcycleslip).– Biasflagfixingreport:Fixcolumn(TorF)indicatesifbiaswas

successfullyfixed.TheFcodecolumnindicateswhyitwasnotfixed.• Thissequenceisrepeateduntilaniterationwhennonew

biasesarefixed.• Thefinalpositionestimatesarethencomputedandoutputin

therequestedformats.


FcodeInterpretation• Forfloat_typeLCtheFcodeis• S-- Floatingpointestimatesigmatoolarge(SigLimit)• W-- MWWLsigmatoolarge• R-- Relativeranknotlargeenough• C-- Chi**2incrementtoolargeforthebestchoiceof

ambiquities• O-- Oneotherbiasinthedoubledifferencesnotfixedyet.

* BF S PRN Epoch Range F Estimate dLC Sig Limit Relative Rank Fix Fcode Change L1 L2 Residual L1 L2 Fits Best LC WL LG175 5 PRN 15 1 43 1 1.86 +- 0.24 SL 0.25 RR 2.36 F F --R-- dL1,2 3 3 dL12 0.31 -0.08 Fits 11.7 0.8 0.3 105.748 2 PRN 07 1 429 1 -0.16 +- 0.74 SL 0.25 RR 9660.51 F F S---O dL1,2 0 0 dL12 -0.28 -0.02 Fits 0.4 0.1 0.1 2.1


Improvingambiguityresolution• TheFcodes canindicatehowtofixambiguitiesthattrackby

defaultisnotabletofix.• Commonfixes:

– SandWindicatethattheestimatedsigmas onthefloatestimatesand/orMW-WLaretoolarge.Iftherelativeranksarelarge,thethesigmatolerancescanbeincreasedwiththeFloat_type command,

– Ifambiguitiesseemtohavethesamevaluethenuser_delbf canbeusedtoremoveanextraonebutcareshouldbetakenbecausesomereceiverscanhave1/1L1L2cycleslips.

– Chi-squaredincrementsmaybetoolarge(especiallyLG(ionosphere)andsometimesWLso,bydown-weightinginthefloat_type command,relativerankcanbeimproved.


Inputionosphericdelaymodel• Version1.26andgreateroftrackhavetheabilitytoreadagriddedionosphericdelaymodel.TheformatofthismodelisexpectedtomatchthecurrentIGSglobalionosphericmodelsavailablefromcddis.gsfc.nasa.govinthegps/productions/ionex/<yyyy>/<ddd>directory.

• CommandIONEX_FILE<filename>invokesthefeatures.TheEX-WLestimatesareaffectedbythismodelanditsinclusionshouldhelpambiguityresolutiononlongbaselines(>100km).


Useofinputambiguityfile

• Forcertainanalyses,itcanbeusefultomanuallysupplyambiguityfiletotrackusingeitherthe-aoptionortheamb_filecommand.

• Theambiguityfilecanbegeneratedbygrep’ing FINALinthetracksummaryoroutputfileandre-directingintoan


Othertunableparameters• Processnoisetobeusediftheatmosphericdelayisvariable– Ifnoiseistoolarge,thenheightestimatesandatmosphericdelayestimatesarehighlycorrelated

– Ifnoiseistosmall,thenatmosphericdelayvariationsmapintoheightvariations

– Foraircraft,tracknowhasprocessnoisethatdependsontherateofchangeofaltitude.

– Unitsofprocessnoisearerandom-walkchangeinmetersper unittime(standarddeviationgrowsassquareofnumberofepochs),wherethedefaultunittimeisthesamplinginterval,buttheunitcanbesetwiththetime_unit command


TrackCommands:“Rules”

• Trackcommandfilessharethepropertiesasglobk commandfiles:– Allcommandlinesmuststartwithalessoneblankspace;argumentsareseparatedbyspaces

– Orderofcommandsisgenerallynotimportantexceptthatlaterversionsofacommandreplacethepreviouslyassignedarguments

– Sitedependentcommandsintrackissuethecommandnamefirstandthenlinesthatcontainstationnamesandarguments(allisavalidname).


Plottingtrackresults

• sh_plot_track isascript(usingGMT)thatcanplottrackresults.Featuresarestillbeingaddedtothisscript.

• Forquickplotsweusethegamit/globk X-windowsprogram cplotx.

• WealsouseKaleidagraph (commercialprogram),Matlab andGMT

• OutputfilesareASCIIwithavarietyoftimetags(YYMMDDHRMINSEC,FractionalDayandEpochnumber)


Finalcomments• Themostcommonparametersthatneedtobechangedintrack

are:– Thedatagapthatwillautomaticallybetreatedasacycleslip(default

is1)butmosthighratedata(>=1Hz)hasgapsduetorecordingproblems.

– ThesigmalimitsfortheLCestimateandMW-WLestimatesoftenneedtobeincreased.Trackhasacorrelationtimeinsigmacalculationthatforthedefaultsettingcanmakethesigmas toolarge.

– Makesureantennaandreceiverinformation(ifmixed)arecorrect.– Treatmentoftheatmosphericdelay.Thereisahighcorrelation

betweentheatmosphericdelayandheightwhenbotharestochastic(RhoUA columninoutputtimeseries).

– WeightfortheEX-WL(effectedbytheionosphere)onlongbaselinesandwhentheionosphereisactive.Ionex_file commandmayhelp.


Trackcommands(The@denotesatleastoneblankinthelinesbelow).@OBS_FILE@SiteRX_file Type

Commandgivesthesite4-charcodesandthecorrespondingrinex filename.The

<Type>issettoFforafixedsite,andKforakinematicsite.e.g.,obs_filebish bisha289.97oFt39at391a289.97oK


TrackCommands@NAV_FILE<name><SP3/NAV>GivesthenameoftheSP3orNAVfilewithorbitsandclock

information(e.g.,igs SP3files).Whenprocessing24-hoursofdata,SP3filesfromtheprecedingand

postcedingdaysshouldbeconcatenatedtogether(headersremovedattheday

boundaries).e.g.,nav_file igs09274.sp3SP3

(GAMITprogramdoy canbeusedtogetGPSweekanddaynumberfromcalendardate).

IfNAVisusedasthetypethenabroadcastephemerisfileisused.


TrackCommands@MODE<Type>TheMODEcommandallowsthesettingofdefaultsforthetypeofdata

beingprocessed.Thesesettingcanthenbeoverwrittenifdesiredbyuseofthecommandsbelow.Threedefaultsettingmodesaresupportedfor<Type>:

AIR-- Assumedtobehigh-samplerateaircraft.Setstheanalysis_typetoLC,andallowsgapsof4-epochs,andminimumdataof120epochs(1minutefor2Hzdata).

SHORT-- Shortbaselinestaticdata(<1km).SetsanalysistypetoL1+L2andminimumdataof20epochs(10minutesof30secondsampleddata).Dataisstillprocessedaskinematicdata.

LONG-- Longbaselinestaticdata(>1km).SetssearchandanalysistypetoLCandmininum dataof20epochs.Atmosphericdelayestimationisturnedonwith0.1m apriorisigma,andprocessnoisevarianceof1.d-6m**2/epoch(~1mmchangesevery30secondsfor30secondsampleddatawhichaccumulatesto+-5cminaday).Thesesettingsarethesameasatm_stats 0.10.001


TrackCommands@SITE_POS@Site<X(m)><Y(m)><Z(m)><Vx (m)><Vy (m)><Vz (m)>

<Epoch(yrs)>Siteisthefourcharacternameofthesite(morecharacterscanbe

includedbutonlythefirst4arechecked).Sitenamesthatdonotappearinthelistofsitestobeprocessedareignored).Theremainderofthelinecontainspositionandvelocityandtheepochindecimalyearstowhichthepositionrefers.

• Velocityisoptional• Ifthiscommandnotused,rinex headercoordinatesareused(can

beaproblemwithtruekinematicsitesthatmovelargedistances.Inthesecasespositionshouldbeforstartofdata.BADPREFITclockerrormessagesareanindicationthatcoordinatesmaybebad).


TrackCommands@SITE_STATS@Site<AprioriSigmainXYZ><RWnoiseinXYZ>Givesstatisticstoassigntothekinematicstationpositions.The<AprioriSigmainXYZ>arethethreesigmas inXYZfortheinitialpositionand<RWnoiseinXYZ>arethethreesigmas inXYZforthechangeinpositionbetweenepochsofdata.Sincethemotionofthekinematicsitesismodeledasrandomwalk(RW),thesigmaofthechangeinpositiongrowsasthesqrt(number ofepochs)

Ver 1.21andlater:RWnoiseissigmas (m)/sqrt(time unit)wheretime_unit commandisusedtosettimeunit.ALLcanbeusedforthestationnameandthesamestatisticswillbeappliedtoallkinematicsites(NOTE:thefixedsitedonotchangeposition).e.g.site_statsall202020202020

(20metersapriorisigmas andchangesof20metersbetweenepochs).Feature1.24:AddedPOSTasentryaftertheApriorisigmavalues,toallowspecificationaposteroi sigmaforpositionattheendofthedataspan.


Trackcommands@TIMEDEP_PROCNS@SiteSigXYZ(m/sqrt(t))StartYYMMDDMNSecEndYYMMDDMNSec

Allowstimedependentprocessnoisetobeaddedthestatisticsofasiteortoallsites.Thenoisesigmas areadded(inavariancesense)tothenoiseprocessesspecifiedintheSITE_STATScommand.Noteonlytherandomwalkprocessnoiseischanged.

Thiscommandisusefulforlong-baselineprocessingofsurfacewavearrivals(processnoiseincreasedduringsurfacewavearrivals).


Trackcommands@ATM_STATS@Site<AprioriZenithdelaysigma><RWnoiseinZenithdelay><RWdH/dt

noise/SCALE>Givesthestatisticsfortheatmosphericdelaysbysite.Thevaluesaretheinitialsigma

inmeters,RWchangesinmetersperepochand(addedversion1.2)adH/dtvariancetermsothatduringrapidheightchangesmoreprocessnoisecanbeaddedtozenithdelayestimate.Theprocessnoisevarianceis(<RWdH/dtnoise)*abs(dh/dt)>^2perepochwheredh/dt ism/s.Typicalvalueis0.00023

e.g.,atm_statst39a0.10.00030.00023

Settheapriorisigmaas10cmandallowsthedelaytochange0.3mmeveryepoch(for1Hzdata,thisleadto18mmnoisein1hr)and2.3mmperepochwhenheightischangingat10m/s(fastascentordesent)

TheSCALEoptioninsteadofthedH/dt term,estimatesanatmosphericdelayscalefactorasafunctionoftheheightdifferencebetweenthebase-stationandaircraft.Ifthebasestationisfarfromtheaircraftstartinglocation,thenaconstantatmosphericdelaytermatthebasestationshouldbeestimated.


TrackCommands@REF_NEU<X(m)><Y(m)><Z(m)>SetthetheXYZcoordinatesofthepointrelativetowhichNEUoffsetsarecomputed.Defaultisthecoordinatesofthefirstsiteintheobs_file list.

@TIME_UNIT<epoch/sec/min/hour/day>Setsthetimeunitforprocessnoise.Choicesareepoch(default),seconds,minuteshourorday.Intervalcommandmustbeusedtospecifysamplingintervalbeforethiscommandisused.(Evenwhentheintervalisgivenintherinex files).


TrackCommands@DATA_NOISE<L1><L2><P1><P2><Elev Weight>[PRN]Allowsspecificiation ofthenoiseintheL1phase,L2phase,P1

rangeandP2range,andtheweightgiventoelevationangledepedence (atver 1.20);varianceisscaledby(1+(W/sin(el))^2)whereWisthe<Elev Weight>.

Thesevaluesaffectthesigmas printedforthepositiondeterminations(Units:m forall,exceptweight)

Optional:PRNmaybeaddedandnoiseassignedtothatPRN(ifnon-PRNformisused,thiswillreplaceallPRNspecificvaluessousethenon-PRNfirstfollowedbyspecificPRNvalues


Trackcommands@DATA_TYPE<choice1><choice2>...Allowsspecificationofdatatypestobeusedingeneratingpositionestimates.Thechoicesare:L1-- L1onlyphaseL2-- L2onlyphaseLC-- IonosphericdelaycorrectedphaseP1-- L1pseudo-rangeP2-- L2pseudo-rangePC-- Ionosphericdelaycorrectedpseudo-range.Thedatatypesmaybecombinedineachofthechoices,e.g.,L1+L2wouldusebothL1andL2whileassumingthattheionosphericdelayis

negligible.Example:data_type l1l1+l2lc+p1Thiscommandsallowsmultiplesolutionstobeoutputfromtheonerun.

NOTE:Thefloat_type commanddeterminesthedatatypeusedtoresolveambiguities.


Completelistcommands@OBS_FILE@SiteRX_file Type@SiteRX_file Type@NAV_FILE<name><SP3/NAV>@MODE<Type>@SITE_POS@Site<X(m)><Y(m)><Z(m)>@REF_NEU<X(m)><Y(m)><Z(m)>@TIME_UNIT<epoch/sec/min/hour/day>@SITE_STATS@Site<AprioriSigmainXYZ><RWnoiseinXYZ>@TIMEDEP_PROCNS@SiteSigXYZ(m/sqrt(t))StartYYMMDDMNSecEndYYMMDDMNSec


Completelistcommands@ATM_STATS@Site<AprioriZenithdelaysigma><RWnoiseinZenithdelay><RW

dH/dt noise/SCALE>@ATM_BIAS@Site<Atmosphericdelayoffset(m)>@ATM_FILE<Filename>@USE_GPTGMF<Relativehumidity(0-1)>@ANTE_OFF@Site<ARPdN (m)><ARPdE (m)><ARPdU (m)><AntennaName>@BF_SET<Maxgap><Mingood>@DEBUG<StartEP><EndEP>@DATA_NOISE<L1><L2><P1><P2><Elev Weight>[PRN]


Completelistofcommand@DATA_TYPE<choice1><choice2>...@OUT_SIG_LIMIT<sigma(m)>@RMS_EDIT_TOL<n-sigmalimit>@EDIT_SSV<site><prn #><starttime><stoptime>@USR_ADDBF<site><prn #><time(ymdhms)>@USR_DELBF<site><prn #><time(ymdhms)>@AMBIN_FILE<filename>@ANTMOD_FILE<filename>@FLOAT_TYPE<Start><Decimation><Type><FloatsigmaLimits(2)>

<WL_Fact><Ion_fact><MAX_Fit>[RelRank]@MIN_TOLS<minLCsig><WLTau>@BACK_TYPE<string>@ION_STATS<Jump><IONPPM><IONWeight><IONheight><IONspatial>@POS_ROOT<string>


Completelistofcommands@RES_ROOT<string>@SUM_FILE<string>@WLS_ROOT<string>@RWL_ROOT<string>@OUT_TYPE<string>@IONEX_FILE<filename>@CUT_OFF<minelevationangle>@START_TIME<YearMonthdayhourminsec>@INTERVAL<seconds>@NUM_EPOCHS<number>@EXCLUDE_SVS<listofPRNnumberstobeexcluded>@STOPGO_MODE<Variancereduction>@MWWL_JUMP<tol cycles>


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