Precise GNSS clock-estimation for real-time navigation and precise point positioning [Elektronische Ressource] / André Hauschild

André Hauschild

Informations

• Publié par: technische_universitat_munchen
• Publié le: 01 janvier 2010
• Nombre de lectures: 29
• Langue: English
• Poids de l'ouvrage: 16 Mo

Extrait

¨ ¨FAKULTAT FUR BAUINGENIEUR-
UND VERMESSUNGSWESEN
PreciseGNSSClock Estimation
forReal TimeNavigation
andPrecisePointPositioning
Dissertation
von
Andre´ Hauschild
¨TECHNISCHE UNIVERSITAT
¨MUNCHENTechnische Universit¨at Munc¨ hen
Institut fur¨ Astronomische und Physikalische Geod¨asie
Precise GNSS Clock-Estimation
for Real-Time Navigation
and Precise Point Positioning
Andr´e Hauschild
Vollst¨andiger Abdruck der von der Fakult¨at fur¨ Bauingenieur- und Ver-
messungswesenderTechnischenUniversit¨atMu¨nchenzurErlangungdes
akademischen Grades eines
Doktor – Ingenieurs
genehmigten Dissertation.
Vorsitzender: Univ.-Prof. Dr.-Ing. U. Stilla
Prufer¨ derDissertation: 1. Univ.-Prof. Dr. phil. nat. U. Hugentobler
2. Priv.-Doz. Dr. rer. nat. habil. O. Montenbruck
3. Prof. Dr. R. B. Langley
University of New Brunswick, Kanada
Die Dissertation wurde am 27.04.2010 bei der Technischen Universit¨at
Munch¨ en eingereicht und durch die Fakult¨at fur¨ Bauingenieur- und Ver-
messungswesen am 28.06.2010 angenommen.Summary
In this dissertation, a complete system for GNSS clock offset estimation in real time
hasbeendevelopedandimplemented.Thethesisbeginswithanoverviewoftheatomic
standards on board of GNSS satellites. A brief review of the historic GPS satellites
is followed by a more detailed summary of the currently active satellites. The clock
performanceisanalyzedandcomparedamongthedifferentclocktypesandanoutlook
isprovidedtofuturesatellites.
The real time network, which provides the measurements for the real time clock
estimation, is presented. The existing techniques for real time dissemination of GNSS
measurementsareintroducedwithashortoverviewanddiscussionofexistingdatafor-
mats. Next, the stations selected for processing are introduced and the measurement
performanceischaracterized.AnoverviewoftheCOoperativeNetworkforGioveOb
servations (CONGO) is provided, which is the first receiver network for global obser-
vationsoftheGIOVEsatellites.
The REal TIme CLock Estimation (RETICLE) system, which has been developed
in the course of this thesis, is introduced in the next chapter. A general overview of the
system, is followed by the description of the models used for GPS and GIOVE obser-
vations and the design of the Kalman filter, which is the core algorithm of the system.
The solution for satellite clock jump detection and mitigation is described. Finally, the
effect of orbit errors on the clock estimation is analyzed and mitigation methods are
described.
Theanalysissectionstartswithorbitdeterminationresultsobtainedwithrealflight
datafromtheTerraSAR Xsatelliteinsimulatednearreal timeorbitdeterminationsce
narios.Theorbitaccuraciesforareduced dynamicsandakinematicorbit
areshown.Areal timecapablenavigationalgorithmisalsoanalyzedtodemonstratethe
potential performance if the RETICLE clock estimates would be broadcast via geosta
tionaryrelaysatellitesforon boarduse.
AnoverviewoftheIGSreal timepilotprojectispresentedinthefollowingchapter.
TheRETICLEclockshavebeensubmittedasacontributiontotheprojectformorethan
a year. The statistics derived by the analysis center coordinator from orbit and clock
comparisonswithrespecttotheIGSRapidproductarepresented.
ResultsfortheGIOVEreal timeclockestimationareThechapterbriefly
introduces the real time processing of the observations from the dedicated GIOVE
trackingnetworkandthegenerationofthecombinedGPS/GIOVEorbitandclockprod
uct.ThequalityoftheGIOVEreal timeclocksisanalyzedandresultsforsingle point
positioningandprecisepointpositioningwithGPSandGIOVEareshownforaselected
testcase.Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 OverviewandProblemStatement . . . . . . . . . . . . . . . . . . . . 1
1.2 CurrentStateoftheArt . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 ThesisOverview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4 ResearchContributions . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 TheAtomicStandardsofGNSSSatellites . . . . . . . . . . . . . . . . . . 9
2.1 HistoricGPSSatellites . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.1 BlockI . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.2 BlockIISatellites . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 CurrentGPSSatellites . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2.1 BlockIIASatellites . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2.2 BlockIIR/IIR MSatellites . . . . . . . . . . . . . . . . . . . . 10
2.3 FutureGPSSatellites . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.1 BlockIIFSatellites . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.2 BlockIII . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4 GIOVESatellites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3 Real TimeTrackingNetwork . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.1 NetworkArchitecture . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.2 SiteCharacteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.3 GIOVETrackingNetwork . . . . . . . . . . . . . . . . . . . . . . . . 24
4 Real TimeClockEstimation . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1 RETICLEOverview . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.2 ModelingofGNSSObservations . . . . . . . . . . . . . . . . . . . . . 32
4.2.1 ReferenceStationPosition . . . . . . . . . . . . . . . . . . . . 34
4.2.2 RelativisticCorrection . . . . . . . . . . . . . . . . . . . . . . 34
4.2.3 Tropospheric . . . . . . . . . . . . . . . . . . . . . 35
4.2.4 AntennaPhaseCenterCorrection . . . . . . . . . . . . . . . . 36
4.2.5 PhaseWind UpCorrection . . . . . . . . . . . . . . . . . . . . 37
4.2.6 CodeBiasCorrection . . . . . . . . . . . . . . . . . . . . . . . 38
4.3 FilterDesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.4 SatelliteClockDiscontinuityDetection . . . . . . . . . . . . . . . . . 52
4.4.1 DiscontinuityDetectionandRecoveryScheme . . . . . . . . . 53
4.4.2 ExamplesofGPSClockJumps . . . . . . . . . . . . . . . . . 54XII Contents
4.4.3 ProblemsandLimitations . . . . . . . . . . . . . . . . . . . . 59
4.5 EffectsofOrbitErrorsonClockEstimation . . . . . . . . . . . . . . . 61
4.5.1 IGSUltra RapidPredictedOrbitErrorAnalysis . . . . . . . . . 61
4.5.2 EffectsofRadial,TangentialandNormalOrbitErrors . . . . . 63
4.5.3 MethodsforMitigation . . . . . . . . . . . . . . . . . . . . . . 73
5 PerformanceAssessmentwithPreciseOrbitDetermination . . . . . . . . 77
5.1 ClockAccuracyAssessment . . . . . . . . . . . . . . . . . . . . . . . 77
5.2 OrbitDeterminationProcedure . . . . . . . . . . . . . . . . . . . . . . 79
5.3 PODResultsandComparisons . . . . . . . . . . . . . . . . . . . . . . 82
5.3.1 ReducedDynamicsOrbitDetermination . . . . . . . . . . . . . 82
5.3.2 KinematicPointPositioning . . . . . . . . . . . . . . . . . . . 90
5.3.3 KalmanFilterbasedReal TimeNavigation . . . . . . . . . . . 92
6 IGSReal TimePilotProject . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.1 OverviewandStatus . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.2 Real TimeProductComparisons . . . . . . . . . . . . . . . . . . . . . 98
7 GIOVEReal TimeClockEstimation . . . . . . . . . . . . . . . . . . . . . 105
7.1 Real TimeClockProcessforGIOVE . . . . . . . . . . . . 106
7.2 CombinedGPS/GIOVEPositioning . . . . . . . . . . . . . . . . . . . 111
7.2.1 SinglePoint . . . . . . . . . . . . . . . . . . . . . 111
7.2.2 PrecisePointPositioning . . . . . . . . . . . . . . . . . . . . . 112
8 Summary,ConclusionsandFutureWork . . . . . . . . . . . . . . . . . . 117
TableofSymbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
TableofAbbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1331. Introduction
1.1 OverviewandProblemStatement
TheGlobalPositioningSystemhasbeenthemostwidelyusedsatellitenavigationsys
tem for decades. The range of applications is manifold and reaches far beyond navi
gation and time transfer, which have been the original purposes of the system. Many
scientific applications of GPS require precise orbit and clock offset information. One
specific example, which will be discussed in further detail in this dissertation, is the
precise orbit determination (POD) of satellites in low Earth orbit (LEO). A growing
number of satellite missions requires the satellite orbit to be determined shortly after
thegroundstationpass,becauseitisthefoundationforconsequentdataanalysisofthe
satellite’s payload. The observations of the LEO satellite’s GPS receiver are available
shortly after the data dump to the ground station, but for positioning with these data,
precise orbit and clock data of the complete GPS constellation is also required with
the same low latency. Predictions of clock offset and drift, which are provided for ex
ample in the predicted part of the IGS ultra rapid orbits or the broadcast ephemerides,
deviate quickly from the true values by several decimeters or even meters. This degra
dationisduetoth