Projekt SATNAV-SIM, 'Entwicklung eines Systemsimulators fuer ein Satellitennavigationssystem GNSS 2' Abschlussbericht

A simulator is built up to support and to optimize the development of a future satellite navigation system. A can Model all important element of the system. With this tool the interaction between the navigation components can be checked and important parameters can be interpret. The reaction of the hole system or of some components can be evaluated for definied error sources. Mathematical models for the system elements have to be developed and integrated in the software code of the complex simulation tool. The transmission channel of the signals is also a system element. (orig.)SIGLEAvailable from TIB Hannover: F98B1360+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA) GmbH, Bonn (Germany)DEGerman

Ein lernfaehiger Fuzzy-Verteilungsschaetzer zur adaptiven Analyse von Radardaten

Presented is a new learning fuzzy distribution estimator (LFVS). It estimates similarities between pattern distributions and the distribution of a signal which is to be analysed. Learning capability gives a high flexibility to the system. Its application is not restricted to SAR data analysis. Compared to conventional estimation algorithms, there are two significant advantages of the fuzzy approach: One is that the gradual similarity between density distributions can be established, and the other is the estimation of reliability without additional computations. The fuzzy distribution estimator is applied to compress SAR raw data and it is a main modul of a new fuzzy classification system. This system allows a user adaptive classification of SAR image data. In addition to the classification itself, the user gets pixel by pixel classification reliability. Pixels belonging to several classes - a typical problem of low resolution radar images - are well detected. (orig.)Available from TIB Hannover: RN 437(99-03) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Aspekte der Uhrensynchronisation, Zeithaltung und -verteilung bei der Konzeption zukuenftiger Satelliten-Navigationssysteme

The thesis investigates time aspects of satellite-based navigation systems to be newly developed. All three areas of clock synchronisation, time keeping and time dissemination are covered. As a start-up the conventional systems GPS and GLONASS are discussed. One- and two-way synchronisation methods are described in a mathematical manner, and a new evaluation method for a TDMA-Crosslink is introduced. Carrier phase observations are analysed for their applicaation in clock comparisons. An overview about precision oscillators is given, and the main impacting noise types are described. A design algorithm for a system time based on a clock ensemble is derived. Tools are developed to estimate clock errors with respect to navigation and timing users. The author developed a simulation tool for clocks and a system time which was used on four different study cases to optimise the system. Finally, recommendations are given for the structure of future navigation systems, i.e. the European GALILEO. (orig.)Die Dissertation befasst sich ausfuehrlich mit Zeitaspekten bei der Entwicklung neuer Satelliten-Navigationssysteme. Dabei wird vor allem auf die eng miteinander verknuepften Aspekte der Uhrensynchronisation, Zeithaltung und -verteilung eingegangen. Zunaechst wird sich an den konventionellen Systemen GPS und GLONASS orientiert. Ein- und Zweiweg-Synchronisationsverfahren werden mathematisch hergeleitet und eine neue Auswertemethode fuer einen TDMA-Crosslink wird vorgestellt. Die Traegerphasenmessung wird fuer Uhrenvergleiche betrachtet. Ein Ueberblick erfolgt zu Praezisionsoszillatoren und deren grundlegend zu beachtetenden Rauschprozessen. Ein Algorithmus zum Entwurf einer auf einem Uhrenensemble basierenden Systemzeitskala wird skizziert. Schliesslich werden Routinen fuer die Abschaetzung des Uhrenfehlers im Navigationssystem fuer Navigations- und Zeitnutzer entwickelt. Ein vom Autor erstelltes Simulationsprogramm zur Uhren- und Systemzeitgenerierung liefert anhand von vier verschiedenen Szenarien Aussagen zur Optimierung des anvisierten Systems. Somit koennen abschliessend Empfehlungen fuer den Aufbau zukuenftiger Navigationssysteme, z.B. des europaeischen GALILEO, gegeben werden. (orig.)SIGLEAvailable from TIB Hannover: RA 437(1999-46) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

SATPOS - Satellitenpositions- und Zeitbestimmung fuer GNSS-2. Bd. 2: Bahnbestimmung bei Intersatellit-Verbindungen Abschlussbericht

SIGLEAvailable from TIB Hannover: F00B1160 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Bonn (Germany)DEGerman

Vollpolarimetrische Helligkeitstemperatur-Verteilungen von natuerlichen und kuenstlichen Objekten bei einer Frequenz von 90 GHz

The aim of this work is to make fully polarimetric thermal radiation of real objects accessible to possible applications. First, realistic orders of magnitude of fully polarimetric effects in the Stokes vector of emissivity are studied by some scattering models as for example periodic surfaces and bianisotropic media. Moreover, the design, construction and calibration of a fully polarimetric, quasioptical radiometric measurement system for high resolution measurements of real objects at 90 GHz is considered. With it, results for the Stokes vector in dependence of the aspect angle were obtained for a periodic plastic surface, a plate of wood from a fir, and an anisotropic cloth as well as for two dimensional measurements of several objects including anti-personal-mines and a car. Together with results of calculations, this leads to some starting points of new applications for the analysis of the complete polarimetric information in respect of touchless material control, object classification and terrain models. (orig.)SIGLEAvailable from TIB Hannover: RN 437(98-19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

SATPOS - Satellitenpositions- und Zeitbestimmung fuer GNSS-2. Bd. 3: Methoden der Zeitbestimmung Abschlussbericht

SIGLEAvailable from TIB Hannover: F00B1161 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Bonn (Germany)DEGerman

Polarimetric SAR interferometry

In this work, aspects of electromagnetic vector wave propagation and scattering are considered in relation to investigations on the role of polarisation in synthetic aperture radar interferometry. Based on the Maxwell equations, the underlying principles of radar polarimetry and SAR interferometry are introduced in order to treat a general formulation of vector wave interferometry. It is shown how polarimetric basis transformations may be introduced in SAR interferometry in order to form interferograms between all possible polarisation states. This reveals the strong dependency of the interferometric coherence on the states used to form the interferograms. Then, the coherence optimisation problem, involving maximisation of interferometric coherence is solved, leading to a new coherent polarimetric interferometric decomposition. For the interpretation of the addressed techniques, a simplified stochastic model for an elevated forest canopy is developed, and used to demonstrate the relevance of wave polarisation on the physical interpretation of SAR interferograms. Finally, the technique of polarimetric differential interferometry is introduced. The proposed algorithms are tested against fully polarimetric (scattering matrix) interferometric SIR-C/X-SAR data sets collected during 1994 along the Tien Shan test site over the SE Lake Baikal, Selenga Delta region of Buriatia in South East Siberia, Russia. (orig.)251 refs.Available from TIB Hannover: RA 437(1999-07) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Bestimmung von Regen- und Wasserdampfverteilungen und Transporten mit PRIRODA und Verifikation durch aktive polarimetrische Radarmessungen vom Boden und DIAL Messungen vom Flugzeug aus Schlussbericht

Rain rates as estimated by multispectral microwave radiometry from satellites are error prone depending on microphysical rain cloud structures and varying surface conditions. The initial goal was to verify rain rates estimated by PRIRODA measurements by simultaneous and coordinated measurements with the polarimetric Doppler radar POLDIRAD of DLR. Because reliable PRIRODA Data were not gathered nor available, these investigations were performed for well accessible SSM/I data of the DMSP satellites using similar microwave radiometer channels as on board of PRIRODA. POLDIRAD measurements were performed well coordinated with DMSP overflights for selected different weather situations. Thus, the different available algorithms will be evaluated and improved in relation to the cloud structures as observed by POLDIRAD. Multifrequency and polarimetric microwave radiometer measurements from ground show improvements in quantitative rain rate estimation when using the polarimetric signatures. The airborne water vapour DIAL has been completed to the end of the project period and its performance has been demonstrated. Measurements, coordinated with the microwave radiometers, however have not been possible before the end of the project. (orig.)SIGLEAvailable from TIB Hannover: F00B301 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman

Radar, Amplitude, Phase und Interferometrie Detection - RAPID Endbericht

RAPID was a joint project of the Deutschen Fernerkundungsdatenzentrum (DFD) and Institut fuer Hochfrequenztechnik from the German Aerospace Center (DLR) and Institut fuer Nachrichtenverarbeitung from the University GH-Siegen as partner. The goal was to develop and approve theories, algorithm and processingssystems to use the interferometric data from ERS. In a preoperational processing chain it is possible to generate coherence - and phase products and as final results digital elevation models (DEM). These products can be used by other projects, therefore other geoscientist must not developed these basics products for there applications. Specially DEMs are very necessary and useful. In various test regions the accuracies were investigated. The DEM from ERS tandem have an height accuracy of about 10 m and a geometric resolution of 30 m x 30 m. The preoperational system developed in RAPID in the basis for the InSAR systems for SRTM in 1999 and ENVISAT in 2000. In RAPID also the SAR processing, the coregistration of SLCs and the phase unwrapping was approved. With the chirp-scaling technique complete ERS are processed and up to ten datasets were coregistered. Special filter operations guarantee sufficient result in area with low coherence (<0.3). The phase unwrapping was approved by a new approach, the 2-dim Kalman filter. This filter was developed, implemented and tested with ERS data. (orig.)SIGLEAvailable from TIB Hannover: F99B32+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA) GmbH, Bonn (Germany)DEGerman

On-board SAR processing and data compression for spaceborne SAR systems. SAR-Verarbeitung und Datenkompression an Bord von satellitengestuetzten SAR-Systemen Final report. Abschlussbericht

With CD-ROMAvailable from TIB Hannover: F00B1259 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman