A5040896620- Soil Moisture and Remote Sensing
- Geophysics and Gravity Measurements
- GNSS positioning and interference
- Arctic and Antarctic ice dynamics
- Methane Hydrates and Related Phenomena
- Ocean Waves and Remote Sensing
- Climate change and permafrost
- Ionosphere and magnetosphere dynamics
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Precipitation Measurement and Analysis
- Cryospheric studies and observations
- Oceanographic and Atmospheric Processes
- Soil Geostatistics and Mapping
- Maritime Navigation and Safety
- Coastal and Marine Dynamics
- Underwater Acoustics Research
- Spacecraft Design and Technology
- Spacecraft and Cryogenic Technologies
- Planetary Science and Exploration
- Remote Sensing and LiDAR Applications
- Advanced Frequency and Time Standards
- Inertial Sensor and Navigation
- Underwater Vehicles and Communication Systems
- Calibration and Measurement Techniques
- Freezing and Crystallization Processes
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2020-2024
GFZ Helmholtz Centre for Geosciences
2013-2022
Technische Universität Berlin
2021
Norwegian Polar Institute
2021
University of Bremen
2021
The Ohio State University
2018
University of Potsdam
2014
Year-round observations of the physical snow and ice properties processes that govern pack evolution its interaction with atmosphere ocean were conducted during Multidisciplinary drifting Observatory for Study Arctic Climate (MOSAiC) expedition research vessel Polarstern in Ocean from October 2019 to September 2020. This work was embedded into interdisciplinary design 5 MOSAiC teams, studying atmosphere, sea ice, ocean, ecosystem, biogeochemical processes. The overall aim characterize cover...
GEROS-ISS stands for GNSS REflectometry, radio occultation, and scatterometry onboard the International Space Station (ISS). It is a scientific experiment, successfully proposed to European Agency in 2011. The experiment as name indicates will be conducted on ISS. main focus of dedicated use signals from currently available Global Navigation Satellite Systems (GNSS) L-band remote sensing Earth with study climate change. Prime mission objectives are determination altimetric sea surface height...
The precision of sea surface altimetry using bistatically reflected signals the Global Navigation Satellite System (GNSS) is typically one to two orders magnitude worse than dedicated radar altimeters. However, when scattering coherent, electromagnetic phase carrier signal can be tracked, providing precise ranging measurements. Under grazing angle (GA) geometries, conditions for coherent are maximized, enabling phase-delay altimetric techniques over waters. This work presents first...
This paper evaluates the potential use of reflected signals from Global Navigation Satellite Systems as a source opportunity for retrieval absolute ellipsoidal heights over sea ice. Accurate estimation surface level would be helpful determination ice thickness, key parameter classification and characterization masses. Our analysis is based on altimetric estimations coherent differential phase between direct both cross- co-polar signals. For this purpose, GPS waveforms have been collected...
Abstract Precipitable water vapor (PWV) is an important parameter for climate research and a crucial factor to achieve high accuracy in satellite geodesy altimetry. Currently Global Navigation Satellite System (GNSS) PWV retrieval using static Precise Point Positioning limited ground stations. We demonstrated the kinematic method with shipborne GNSS observations during 20‐day experiment 2016 Fram Strait, region of Arctic Ocean between Greenland Svalbard. The shows agreement ~1.1 mm numerical...
The global navigation satellite system (GNSS) Transpolar Earth Reflectometry exploriNg (G-TERN) was proposed in response to ESA's Explorer 9 revised call by a team of 33 multi-disciplinary scientists. primary objective the mission is quantify at high spatio-temporal resolution crucial characteristics, processes and interactions between sea ice, other components order advance understanding prediction climate change its impacts on environment society. articulated through three key questions....
[1] This paper evaluates the usage of reflected GPS signals for Earth observations to study changes sea level and sea-ice in remote sensing. In a coastal setup, ∼670 m above Disko Bay (Greenland), with different carriers L1 L2 were recorded. A method is presented that analyses interferometric phase between direct derives height reflecting surface. The analysis includes ray tracing an estimation signal coherence. It shown coherent reflections are related coverage. Absolute heights derived...
Abstract Sea surface topography observations are deduced from an airborne reflectometry experiment. A GNSS (Global Navigation Satellite System) receiver dedicated for was set up aboard the German HALO (High Altitude Long Range) research aircraft. Flights were conducted over Mediterranean about 3500 m above sea level. signal path model divided into large‐ and small‐scale contributions is used phase altimetry. The results depict geoid undulations resolve anomalies of topography. For whole...
Global Navigation Satellite System Reflectometry (GNSS-R) has long been explored for retrieving sea ice properties, but in-situ validation in the central Arctic during freezing season is rare, limiting its application. The primary objective of this study to advance current understanding multi-polarization GNSS-R remote sensing ice. This paper presents observations from full-polarization GNSS-R(FpolGNSSR) prototype  during MOSAiC expedition. FpolGNSSR, with four polarization channels...
The Passive REflecTometry and dosimeTrY (PRETTY) satellite has been launched into a low Earth orbit, of about 570 km altitude, on 9th October 2023. Its main payload is dedicated to reflectometry using signals Global Navigation Satellite Systems (GNSS). on-board receiver provides delay maps the Earth-reflected signal. objective mission exploit for ocean sea ice altimetry.Observations are recorded in grazing angle geometry. It means that incident reflected ray reach maximum elevation at...
The characterization of global mean sea level is important to predict floods and quantify water resources for human use irrigation, especially in coastal regions. Recently, the application navigation satellite system reflectometry (GNSS-R) monitoring has been successfully demonstrated. This paper focuses on retrieval surface height within a field experiment that was conducted at Onsala Space Observatory (OSO) using phase-based altimetry method. A continuous phase tracking algorithm, which...
The spaceborne Global Navigation Satellite System-Reflectometry (GNSS-R) delay-Doppler map (DDM) data collected over ocean carry typical feature information about the surface, which may be covered by open water, mixed water/ice, complete ice, etc. A new method based on Doppler spread analysis is proposed to remotely sense sea ice using GNSS-R Northern and Southern Hemispheres. In order extract useful from DDM, three delay waveforms are defined utilized. waveform without shift as central...
This paper presents an altimetric method for ocean monitoring by remote sensing. It uses carrier observations of reflected GNSS signals. The is illustrated in a simulation study and applied to long term experiment yielding tide spectrum. concept based on residual Doppler frequency. A linear relation between residuals f 0 height departures Δ H from the surface level derived. In contrast existing phase‐based methods which are constrained smooth conditions, frequency‐based retrieval here...
This paper describes an altimetric method based on data recorded during experimental zeppelin flights over Lake Constance. Interferometric observations for this are obtained using a Master‐Slave receiver configuration. These contain the relative phasing of direct and reflected signals used altimetry. Separated antennas attached to record at slant elevation angles. Filtering is required remove contributions in geometry. Filtered corrected model, thus Doppler residuals retrieved. correction...
For the first time, rain effects on polarimetric observations of global navigation satellite system reflectometry (GNSS-R) are investigated. The physical feasibility tracking modifications in surface roughness by splash and salinity accumulation freshwater is theoretically discussed. An empirical analysis carried out using measurements a coastal GNSS-R station with two side-looking antennas right- left-handed circular polarizations (RHCP LHCP). Discernible drops RHCP LHCP powers observed...
GPS reflected signals have become a source of opportunity for remote sensing the Earth's suface. In this work, we present several capabilities technique in two different polar environments: Greenland and Antarctica. The first part is dedicated to retrieval sea-ice properties, giving emphasis study coherent phase altimetric roughness estimations, polarimetric measurements determination ice salinity variation. results show good agreement with tide model daily charts. On second part, some...
Reflection power derived from the global navigation satellite system (GNSS) observations and its sensitivity to sea-ice concentration are investigated in this article. A corresponding experiment has been conducted during Fram Strait cruise of Norwegian research vessel <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Lance</i> summer 2016. The dedicated setup with a GNSS Occultation Reflectometry Scatterometry (GORS) receiver dual-polarization...
Reflectometry measurements have been conducted aboard the German research icebreaker Polarstern during MOSAiC expedition (Multidisciplinary drifting Observatory for Study of Arctic Climate).Signals Global Navigation Satellite Systems (GNSS) were recorded using a dedicated GNSS reflectometry receiver retrieval sea-ice reflectivity.The primary goal is reflectometry-based monitoring sea ice as part climate study.The data set presented here covers expedition's first leg (late Sep. to mid Dec....
A geophysical model function (GMF) for sea ice concentration (SIC) retrieval is developed based on the spaceborne Global Navigation Satellite System Reflectometry (GNSS-R) data measured by TechDemoSat-1 (TDS-1) satellite. The spreading characteristics of onboard processed delay-Doppler maps (DDMs) change with surface roughness, which can be related to SIC. GNSS-R observable termed as differential delay waveform (DDW) generated from DDM first used in this article estimate Collocated SIC...
In the last years extreme flood events occur more frequently in Vietnam. Conventional satellite altimeters offer high altimetric accuracy but with insufficient spatial and temporal resolution. Ground based instrumentation enables a resolution, for point location only. GNSS-Reflectometry (GNSS-R) reveals new perspectives water level monitoring. To test possibility of using this innovative technique as gauge instrument, two weeks lasting measurement campaign was conducted Vietnam, February...
Abstract. Within the transpolar drifting expedition MOSAiC (Multidisciplinary Observatory for Study of Arctic Climate), Global Navigation Satellite System (GNSS) was used among other techniques to monitor variations in atmospheric water vapor. Based on 15 months continuously tracked GNSS data including GPS, GLONASS and Galileo, epoch-wise coordinates hourly zenith total delays (ZTDs) were determined using a kinematic precise point positioning (PPP) approach. The derived ZTD values agree 1.1...
GNSS reflectometry (GNSS-R) measurements were conducted in Sep 2012 over Lake Constance between Austria, Germany and Switzerland. A Zeppelin NT (New Technology) type airship equipped with a GORS (GNSS Occultation Reflectometry Scatterometry) receiver setup flight transects (up to 64 km long) at about 500 m altitude above the lake surface. The uses two downwards tilted antennas right-handed left-handed circular polarisation (RHCP LHCP) acquire reflected signal. An up-looking RHCP antenna...