Leibniz Universität Hannover Faculty Faculty of Civil Engineering and Geodetic Science
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Institute of Geodesy
 
Institute of Geodesy Research Research Projects
Finished Research projects

Finished Research Projects

Terrestrial Gravimetry

  • Establishing an Advanced Mexican Gravity Standardization Base
    This joint research project serves for following main scientific objectives: a) supporting the realization of a state of the art national gravity standard in Mexico fulfilling highest accuracy demands in metrology, b) supporting the establishment of a base for a national reference frame for geo-scientific purposes, c) supporting the improvement of a global gravity potential field model for fundamental research in earth science
    Led by: Dr.-Ing. Ludger Timmen
    Team: Dr.-Ing. Ludger Timmen, Dr.-Ing. Manuel Schilling
    Year: 2016
    Funding: Physikalisch-Technische Bundesanstalt Braunschweig
  • Traceability of the FG5X-220 to the SI units
    The Micro-g LaCoste FG5 is a free-fall gravimeter with a laser interferometer in Mach-Zehnder configuration which uses simultaneous time and distance measurements to calculate the absolute value of g. The instrument itself contains the necessary standards, a rubidium oscillator and a He-Ne Laser, and operates independent of external references. These internal standards need regular comparisons.
    Led by: Dr.-Ing. Ludger Timmen
    Team: Dr.-Ing. Ludger Timmen, M. Sc. Manuel Schilling
    Year: 2012
    © IfE / M. Schilling
  • Improved compensation of vibrational noise in the laser interferometer with applications in absolute gravimetry
    Led by: Dr. Sergiy Svitlov
    Year: 2011
    Funding: DFG
    Duration: 2011 - 2018
  • Absolute gravimetry in Denmark
    Led by: Dr.-Ing. Ludger Timmen
    Team: Dipl.-Ing. Olga Gitlein
    Year: 2003

Gravity Field and Geoid Modelling

  • Regional gravity field modeling & relativistic geodesy (CRC 1128, C04)
    Led by: Dr.-Ing. Heiner Denker
    Team: Dr.-Ing. Miao Lin
    Year: 2014
    Funding: Deutsche Forschungsgemeinschaft (DFG)
    Duration: 01.07.2014 – 30.06.2018
  • The recovery of Earth’s global gravity field from GOCE observations
    The ESA’s GOCE (Gravity field and steady-state Ocean Circulation Explorer) mission was the first to jointly apply SGG (satellite gravity gradiometry) and SST-hl (satellite-to-satellite high-low tracking) techniques to map the Earth’s gravity field. It delivered hundreds of millions of observations in four years’ lifetime, from 2009 to 2013. My Ph.D work is to recover a global gravity field model that is described by 62,997 spherical harmonic coefficients (up to degree/order 250) from the huge amount of GOCE observations.
    Led by: Prof. Dr.-Ing. Jürgen Müller
    Team: Dr.-Ing. Hu Wu
    Year: 2011
    Funding: Stipendium
    Duration: 2011-2016
  • GOCE-GRavitationsfeldANalyse Deutschland – GOCE-GRAND II WP220 – Regionales Validierungs- und Kombinationsexperiment
    Within the framework of the project, high-quality validated terrestrial gravity field data sets (in particular deflections of the vertical and gravity data) were generated in Germany and Europe for the external validation of GOCE products. These data were used for the validation of existing satellite gravity models on the one hand and for the calculation of corresponding combined quasigeoid solutions for Germany and Europe on the other hand.
    Led by: Dr.-Ing. Heiner Denker (WP220 - IfE)
    Team: Dr.-Ing. Christian Voigt
    Year: 2005
    Funding: Research and development programme GEOTECHNOLOGIEN, funded by the Federal Ministry of Education and Research (BMBF) and the German Research Foundation (DFG), Förderkennz. 03F0421D
    Duration: 01.09.2005 – 31.08.2008

Relativistic Geodesy

Satellite Gravimetry

GNSS and Inertial Navigation

  • 5GAPS: 5G Access to Public Spaces
    In this research project, the positioning capabilities of the latest mobile communication standard 5G NR are investigated. Due to the increasing demand for communication and the widespread installation of 5G NR networks, terrestrial signal sources can provide an alternative or complement to GNSS signals when GNSS signals are unavailable or a limited by the environment.
    Led by: Prof. Dr.-Ing Steffen Schön
    Team: Kai-Niklas Baasch, M.Sc.
    Year: 2022
    Funding: Federal Ministry of Transport and Digital Infrastructure (BMDV), grant number: 45FG121_F
  • Correction of GNSS multipath effects for reliable autonomous localisation of highly automated vehicles in metropolitan areas (KOMET)
    The code range (code measurement) used in automotive applications often cannot provide the required resolution of the location due to the high measurement noise. The complex GNSS signal propagation (signal shading, multipath effects) in urban environments makes the determination of an accurate and robust positioning solution a particularly challenging task - e.g. for positioning in narrow street canyons. The research project aims to develop and implement innovative correction methods to reduce multipath effects in order to improve carrier phase-based GNSS positioning.
    Led by: Prof. Dr.-Ing. Steffen Schön, Dr.-Ing. Tobias Kersten
    Team: Dr.-Ing. Tobias Kersten, M.Sc. Fabian Ruwisch
    Year: 2020
    Funding: BMWi / TÜV Rheinland Consulting GmbH
    © Ch. Skupin (Bosch)
  • QGyro: Quantum Optics Inertial Sensor Research
    The objective of this research programme is to develop and test high-precision quantum inertial sensors that support conventional inertial navigation sensors in order to expand these sensors to up to 6 degrees of freedom and use them for autonomous navigation in various further development stages.
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: M.Sc. Benjamin Tennstedt, Dr.-Ing. Tobias Kersten
    Year: 2019
    Funding: Federal Minitry of Economics and Climate Affairs (BMWK / DLR), grant number: 50RK1957
    Duration: 2019 - 2022
  • Integrity Monitoring for Network RTK Systems
    From the advent of the satellite positioning techniques, civil users have always been trying to find a way to have more accurate and precise coordinates of their position. Differential concepts, from early days of GPS, have been considered. Applying the RTCM format, made the transmission of corrections possible from reference stations to the users. At first stage the corrections were casted to the users from one single station, which is called single RTK (Real Time Kinematic). This method is limited in some ways; degrading by increasing distance from CORS (Continuously Operating Reference Station), needed same signals at reference and rover and remaining the reference station errors. For compensating these shortages, the Network RTK concept appeared. In NRTK the corrections are produced using a network (at least three) of reference stations. The concept of Precise Point Positioning (PPP) is currently associated with global networks. Precise orbit and clock solutions are used to enable absolute positioning of a single receiver. However, it is restricted in ambiguity resolution, in convergence time and in accuracy. Precise point positioning based on RTK networks (PPP-RTK) overcomes these limitations and gives centimeter-accuracy in a few seconds.
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: Ali Karimidoona, M. Sc.
    Year: 2018
    Funding: German Academic Exchange Service (DAAD)
  • Kinematic GNSS positioning of Low Earth Orbiters (CRC 1128, B03)
    Strengthening the accuracy of kinematic orbits of Low Earth Orbiters through an adopted Precise Point Positioning (PPP) enhanced by GNSS Receiver Clock Modeling and the concept of a Virtual Receiver is the overall objective of this project.
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: M.Sc. Christoph Wallat
    Year: 2014
    Funding: DFG
  • Turbulence investigations and improved modelling of atmospheric refraction with VLBI and GNSS
    Improved characterization of refractivity fluctuations, determination of turbulence parameters and enhanced modelling of neutrospheric refraction effects
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: Dipl.-Ing. Franziska Kube
    Year: 2012
    Funding: DFG (SCHO 1314/3-1)
  • Verbesserte Positionierung und Navigation durch konsistente Multi-GNSS Antennenkorrekturen
    Investigation of effects of code phase delays (GDV) on the GNSS-based positioning and navigation as well as the development of a method for an adequate comparison of different calibration results.
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: Dipl.-Ing. Tobias Kersten
    Year: 2012
    Funding: BMWI | 50NA1216
  • Bürgernahes Flugzeug
    Improvement of quality and decrease of signal loss during GNSS-based curved landing approaches as part of the development of a "Metropolitain Aircraft".
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: Dipl.-Ing. Franziska Kube
    Year: 2011
    Funding: Government of Lower Saxony
  • Navigation und Positionierung in difficult enviornments
    Analyse of High-Sensitivity GNSS Sensors
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: Dipl.-Ing. Olaf Bielenberg
    Year: 2011
  • Modelling physical correlation of GNSS phase observations by means of turbulence theory
    Modelling of physikal Correlations on GNSS Phase Observables using the Approach of turbulence theory
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: Dr.-Ing. Markus Vennebusch
    Year: 2011
    Funding: DFG (SCHO 1314/1-1).
  • Modeling and correction of GNSS multipath effect through Software receiver and Ray tracing
    Describing Multipath by Software receiver and Ray tracing.
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: M.Sc. Marios Smyrnaios
    Year: 2011
    Funding: BMWI and German Aerospace Center (DLR)
  • Investigations of distance dependent systematic effects
    Correction models for distance dependent effects in small GPS networks
    Led by: Dr.-Ing. Steffen Schön
    Team: Dr.-Ing. Steffen Schön
    Year: 2006
  • Assessment of remaining systematic effects by interval mathematics
    Assessment of remaining systematic effects by interval mathematics
    Led by: Prof. Dr.-Ing. Steffen Schön
    Year: 2006
    Funding: Deutsche Forschungsgemeinschaft (DFG)

Lunar Laser Ranging (LLR)

Space Sensor Technologies

  • Swarm ESL/DISC: Support to accelerometer data analysis and processing
    Led by: Prof. Dr.-Ing. Jakob Flury
    Team: Dr.-Ing. Sergiy Svitlov, Dr.-Ing. Akbar Shabanloui
    Year: 2016
    Funding: ESA (DTU Space)
    Duration: 2016-2020
  • Disentangling gravitational signals and errors in global gravity field parameter estimation from satellite observations (SFB 1128, C01)
    Range-rate residuals from the estimation of global gravity field parameters from GRACE satellite-to-satellite tracking reveal a range of systematic effects that limit the accuracy of the estimated parameters. The project investigated the characteristics of time series of range-rate residuals. It addressed how drops in the K-band ranging signal-to-noise ratio at specific inter-satellite Doppler frequencies propagate to anomalies in range-rate residuals, as well as anomalies during penumbra transitions. A part of the project at TU Graz, in the group of Prof. Mayer-Gürr, studied options to use wavelet parameters in the SST gravity field parameter estimation.
    Led by: Prof. Jakob Flury
    Team: M.Sc. Saniya Behzadpour
    Year: 2014
    Funding: DFG
    Duration: 2014-2018
  • Highly physical penumbra solar radiation pressure modeling with atmospheric effects
    During penumbra transitions of an Earth orbiter, the solar radiation hitting the satellite is strongly influenced by refraction and absorption of light rays grazing the Earth’s atmosphere. The project implemented solar radiation pressure modeling including these effects. Model results were tested by comparing with measurements of the accelerometers of the GRACE low Earth orbiters.
    Led by: Prof. Jakob Flury, Tamara Bandikova
    Team: Robbie Robertson (Virginia Tech, Blacksburg, VA)
    Year: 2010
    Funding: RISE/QUEST
    Duration: 2010
  • In-Orbit System Analysis of the Gravity Recovery and Climate Experiment (GRACE) Mission
    Precise determination and control of satellite attitude plays a key role for satellite geodesy in general, and for Satellite-to-Satellite Tracking in particular. The project provided the first in-depth characterization of GRACE pointing biases and pointing variations. Investigations addressed star camera inter-boresight angle variations, the weighted camera sensor head combination, as well as error propagation to inter-satellite ranging and accelerometer observations. Results led to significant improvements in the operational GRACE data processing.
    Led by: Prof. Jakob Flury
    Team: Tamara Bandikova
    Year: 2009
    Funding: Exzellenzcluster QUEST
    Duration: 2009-2015
    © IfE / Bandikova

CRC 1128 (geo-Q)

QUEST

  • Satellite Navigation using high precise Oscillators
    Examination of high precise Oscillators in the application area of Satellite Navigation
    Led by: Prof. Dr.-Ing. Steffen Schön
    Team: Dipl.-Ing. Ulrich Weinbach
    Year: 2011
    Funding: QUEST
  • Potential Field Determination and high precise Oscillators
    Determination of the Earth's Gravity Field using high precise Oscillators
    Led by: Prof. Dr.-Ing. habil. Jürgen Müller
    Team: Dr.-Ing. habil. Enrico Mai
    Year: 2011
    Funding: QUEST (Quantum Engineering and Space Time Research)
  • Highly physical penumbra solar radiation pressure modeling with atmospheric effects
    During penumbra transitions of an Earth orbiter, the solar radiation hitting the satellite is strongly influenced by refraction and absorption of light rays grazing the Earth’s atmosphere. The project implemented solar radiation pressure modeling including these effects. Model results were tested by comparing with measurements of the accelerometers of the GRACE low Earth orbiters.
    Led by: Prof. Jakob Flury, Tamara Bandikova
    Team: Robbie Robertson (Virginia Tech, Blacksburg, VA)
    Year: 2010
    Funding: RISE/QUEST
    Duration: 2010
  • In-Orbit System Analysis of the Gravity Recovery and Climate Experiment (GRACE) Mission
    Precise determination and control of satellite attitude plays a key role for satellite geodesy in general, and for Satellite-to-Satellite Tracking in particular. The project provided the first in-depth characterization of GRACE pointing biases and pointing variations. Investigations addressed star camera inter-boresight angle variations, the weighted camera sensor head combination, as well as error propagation to inter-satellite ranging and accelerometer observations. Results led to significant improvements in the operational GRACE data processing.
    Led by: Prof. Jakob Flury
    Team: Tamara Bandikova
    Year: 2009
    Funding: Exzellenzcluster QUEST
    Duration: 2009-2015
    © IfE / Bandikova

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