Jens Wickert
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View article: Investigations into highly stable GNSS ground and space clocks using a network of globally distributed H-maser stations
Investigations into highly stable GNSS ground and space clocks using a network of globally distributed H-maser stations Open
Modeling station and satellite clocks in the GNSS analysis in order to reduce existing correlations requires a high level of stability for the corresponding clocks. In this contribution, we provide a comprehensive and up-to-date status reg…
View article: Assimilation of global navigation satellite system (GNSS) zenith delays and tropospheric gradients: a sensitivity study utilizing sparse and dense station networks
Assimilation of global navigation satellite system (GNSS) zenith delays and tropospheric gradients: a sensitivity study utilizing sparse and dense station networks Open
The assimilation of global navigation satellite system (GNSS) zenith total delays (ZTDs) into numerical weather models improves weather forecasts. In addition, the GNSS tropospheric gradient (TG) estimates provide valuable insight into the…
View article: DNS (v1.0): an open-source ray-tracing tool for space geodetic techniques
DNS (v1.0): an open-source ray-tracing tool for space geodetic techniques Open
We have developed an open-source ray-tracing tool for space geodetic techniques. The software uses the geometric optics approximation to calculate the signal travel time delay induced by the atmosphere between two given points. The softwar…
View article: Evolution of Post‐Sunset EPBs: Relationships to the EIA Induced by Pre‐Reversal Enhancement Electric Fields
Evolution of Post‐Sunset EPBs: Relationships to the EIA Induced by Pre‐Reversal Enhancement Electric Fields Open
This paper presents Global Navigation Satellite System radio occultation (RO) observational analyses on deducing the relationships and dependences between post‐sunset equatorial plasma bubbles (EPB) occurrences and equatorial ionospheric a…
View article: DNS (v1.0): An open source ray-tracing tool for space geodetic techniques
DNS (v1.0): An open source ray-tracing tool for space geodetic techniques Open
We have developed an open source ray-tracing tool for space geodetic techniques. The software uses the geometric optics approximation to calculate the signal travel time delay induced by the atmosphere between two given points. The softwar…
View article: A Global Assessment of Diurnal Discontinuities in ERA5 Tropospheric Zenith Total Delays Using 10 Years of GNSS Data
A Global Assessment of Diurnal Discontinuities in ERA5 Tropospheric Zenith Total Delays Using 10 Years of GNSS Data Open
The diurnal cycle of tropospheric Zenith Total Delays (ZTD) is critical for refining tropospheric models and understanding key geophysical and atmospheric processes. The fifth European Centre for Medium‐Range Weather Forecasts reanalysis E…
View article: Deep Neural Networks for Refining Vertical Modeling of Global Tropospheric Delay
Deep Neural Networks for Refining Vertical Modeling of Global Tropospheric Delay Open
Kinematic airborne platforms are becoming increasingly vital for Earth observation. They highlight the critical need for accurate tropospheric delay corrections across varying altitudes, especially as most existing models are limited to Ea…
View article: Neural Network-Based Retrieval Optimization of GNSS-IR for Sea Level Monitoring Under Different Elevation Angles
Neural Network-Based Retrieval Optimization of GNSS-IR for Sea Level Monitoring Under Different Elevation Angles Open
The Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) technique has been widely employed to retrieve sea levels by utilizing signal-to-noise ratio (SNR) data, yet its accuracy is often hindered by limitations impos…
View article: Sea Ice Detection from GNSS-R Data Based on Local Linear Embedding
Sea Ice Detection from GNSS-R Data Based on Local Linear Embedding Open
Sea ice plays a critical role in the Earth’s climate system, and its variations affect ecosystem stability. This study introduces a novel method for detecting sea ice in the Arctic Ocean using bidirectional radar reflections from the Globa…
View article: Seasonal–Longitudinal Variability of Equatorial Plasma Bubbles Observed by FormoSat-7/Constellation Observing System for Meteorology Ionosphere and Climate II and Relevant to the Rayleigh–Taylor Instability
Seasonal–Longitudinal Variability of Equatorial Plasma Bubbles Observed by FormoSat-7/Constellation Observing System for Meteorology Ionosphere and Climate II and Relevant to the Rayleigh–Taylor Instability Open
The FormoSat-7/Constellation Observing System for Meteorology, Ionosphere, and Climate II (FS7/COSMIC2) program has acquired over three hundred thousand equatorial plasma bubble (EPB) observations from 2019 to 2023 in the equatorial and ne…
View article: Advancing Accuracy in Sea Level Estimation with GNSS-R: A Fusion of LSTM-DNN-Based Deep Learning and SNR Residual Sequences
Advancing Accuracy in Sea Level Estimation with GNSS-R: A Fusion of LSTM-DNN-Based Deep Learning and SNR Residual Sequences Open
The global navigation satellite system reflectometry (GNSS-R) technique has shown promise in retrieving sea levels using signal-to-noise ratio (SNR) data. However, its accuracy and performance are often limited compared to conventional tid…
View article: Assimilation of GNSS tropospheric gradients into the Weather Research and Forecasting (WRF) model version 4.4.1
Assimilation of GNSS tropospheric gradients into the Weather Research and Forecasting (WRF) model version 4.4.1 Open
In this study, we have incorporated tropospheric gradient observations from a Global Navigation Satellite Systems (GNSS) ground station network into the Weather Research and Forecasting (WRF) model through a newly developed observation ope…
View article: Ionospheric Impact on GNSS Reflectometry: A correction approach for the PRETTY satellite data
Ionospheric Impact on GNSS Reflectometry: A correction approach for the PRETTY satellite data Open
The ionosphere, spanning 60 to 2000 km above the Earth’s surface, plays a crucial role in Global Navigation Satellite System (GNSS) signal propagation, as signals traverse this layer on their path from the GNSS satellite to the recei…
View article: GFZRNX-QC: Advanced GNSS Data Processing and Quality Control for Multi-System Observations
GFZRNX-QC: Advanced GNSS Data Processing and Quality Control for Multi-System Observations Open
GFZRNX-QC software is designed to streamline the processing of Receiver Independent Exchange Format (RINEX) observations and the generation of overall information by providing a robust and efficient solution for data cleaning and quality c…
View article: Building a comprehensive picture of sea surface, troposphere and ionosphere contributions in precise GNSS reflectometry from space
Building a comprehensive picture of sea surface, troposphere and ionosphere contributions in precise GNSS reflectometry from space Open
Signals of Global Navigation Satellite Systems (GNSS) are subjected to propagation effects, like reflection, refraction and scintillation. Twenty years ago, a first dedicated payload has been launched on a satellite mission (UK-DMC) to stu…
View article: PRETTY – First experience from a 3U CubeSat In-Orbit Demonstrator for GNSS-Reflectometry under grazing angle geometry
PRETTY – First experience from a 3U CubeSat In-Orbit Demonstrator for GNSS-Reflectometry under grazing angle geometry Open
The PRETTY CubeSat In-Orbit Demonstrator (IOD) Mission has been finally launched on 9th October 2023 into a Sun-Synchrounous Orbit (SSO) in 560km height. The Launch and Early Orbit Phase (LEOP) was successful, meaning that communication wi…
View article: Diurnal Vegetation Moisture Dynamics and Water Stress: Insights from GNSS Reflectometry-Derived Vegetation Water Content
Diurnal Vegetation Moisture Dynamics and Water Stress: Insights from GNSS Reflectometry-Derived Vegetation Water Content Open
The dynamics of Vegetation Water Content (VWC) throughout the day reflect how plants cope with water stress, trying to replenish lost water during daylight hours. Traditional radar sensors have shown sensitivity to diurnal vegetation moist…
View article: Investigations into GNSS clock biases in a global network of IGS H-Maser stations
Investigations into GNSS clock biases in a global network of IGS H-Maser stations Open
Global Navigation Satellite Systems (GNSS) are based on measuring the time that elapses between the signal’s transmission at the satellite and its reception on the ground. Therefore, clock information is required on both sides. While…
View article: Validation of GNSS-based Integrated Water Vapor for the Swabian MOSES 2023 field campaign
Validation of GNSS-based Integrated Water Vapor for the Swabian MOSES 2023 field campaign Open
The Swabian MOSES (Modular Observation Solutions for Earth Systems) field campaign was conducted between June and September 2023 in the southeastern Black Forest, the Neckar Valley and the Swabian Alb in southwestern Germany. It focused on…
View article: GNSS Precipitable Water Vapour for Climate Monitoring
GNSS Precipitable Water Vapour for Climate Monitoring Open
Aside from main geodetic applications, the Global Navigation Satellite System (GNSS) is now an established observing system for atmospheric water vapour which is the most important greenhouse gas as it is responsible for around 60% of the …
View article: GNSS radio occultation data for weather forecast and climate research
GNSS radio occultation data for weather forecast and climate research Open
The GNSS radio occultation (RO) technique uses GNSS (Global Navigation Satellite Systems) signals received aboard low Earth orbiting satellites for atmospheric limb sounding. Refractivity and temperature profiles are derived with high vert…
View article: GNSS Precipitable Water Vapor for Climate Monitoring
GNSS Precipitable Water Vapor for Climate Monitoring Open
Water vapour is under-sampled in the current climate-observing systems and obtaining and exploiting more high-quality humidity observations is essential for climate monitoring. Global Navigation Satellite System (GNSS) is an established ob…
View article: Deep Learning in Spaceborne GNSS Reflectometry: Correcting Precipitation Effects on Wind Speed Products
Deep Learning in Spaceborne GNSS Reflectometry: Correcting Precipitation Effects on Wind Speed Products Open
Deep learning techniques have shown the capability in GNSS reflectometry (GNSS-R) for retrieving geographical parameters based on GNSS-R observations. Recent studies have proved that such data-driven approaches can significantly improve th…
View article: GNSS-R Snow Depth Inversion Study Based on SNR-SVR
GNSS-R Snow Depth Inversion Study Based on SNR-SVR Open
The global navigation satellite system reflectometry (GNSS-R) technology has shown significant potential in retrieving snow depth using signal-to-noise ratio (SNR) data. However, compared to traditional in situ snow depth measurement techn…
View article: Snow Depth Retrieval Using Detrended SNR From GNSS-R With Bidirectional GRU
Snow Depth Retrieval Using Detrended SNR From GNSS-R With Bidirectional GRU Open
Snow depth monitoring is crucial for hydrology, climate research, and avalanche prediction. While traditional global navigation satellite system (GNSS) reflectometer methods offer cost-effective snow thickness retrieval, they suffer from p…
View article: Assimilation of GNSS Tropospheric Gradients into the Weather Research and Forecasting Model Version 4.4.1
Assimilation of GNSS Tropospheric Gradients into the Weather Research and Forecasting Model Version 4.4.1 Open
In this study, we have incorporated tropospheric gradient observations from a Global Navigation Satellite Systems (GNSS) ground station network into the Weather Research and Forecasting (WRF) model through a newly developed observation ope…
View article: Combined GNSS reflectometry–refractometry for automated and continuous in situ surface mass balance estimation on an Antarctic ice shelf
Combined GNSS reflectometry–refractometry for automated and continuous in situ surface mass balance estimation on an Antarctic ice shelf Open
Reliable in situ surface mass balance (SMB) estimates in polar regions are scarce due to limited spatial and temporal data availability. This study aims at deriving automated and continuous specific SMB time series for fast-moving parts of…
View article: Characterizing Ionospheric Effects on GNSS Reflectometry at Grazing Angles from Space
Characterizing Ionospheric Effects on GNSS Reflectometry at Grazing Angles from Space Open
Coherent observations in GNSS reflectometry are prominent in regions with smooth reflecting surfaces and at grazing elevation angles. However, within these lower elevation ranges, GNSS signals traverse a more extensive atmospheric path, an…
View article: Tidal harmonics retrieval using GNSS-R dual-frequency complex observations
Tidal harmonics retrieval using GNSS-R dual-frequency complex observations Open
Tidal analysis and methods for estimation and prediction of ocean tidal constitutes are essential in a large area of scientific disciplines, for example, navigation, onshore and offshore engineering, and production of green energy. Ground-…
View article: Sea Ice Detection from GNSS-R Data Based on Residual Network
Sea Ice Detection from GNSS-R Data Based on Residual Network Open
Sea ice is an important component of the polar circle and influences atmospheric change. Global navigation satellite system reflectometry (GNSS-R) not only realizes time-continuous and wide-area sea ice detection, but also greatly reduces …