The Gravity Recovery and Climate Experiment-Follow-On (GRACE-FO) mission, successfully launched on May 22, 2018, is a joint NASA-GFZ project to continue the the objectives and data sets of the original GRACE (2002-2017) mission.

The GRACE-C Mission is a joint NASA-DLR project to continue the time series of mass change measurements of the original GRACE and GRACE-FO missions, again with significant GFZ contributions.

The research group NEROGRAV focuses on improving and better understanding of sensor data, background models, and processing strategies of satellite gravimetry to increase the resolution, accuracy, and long-term consistency of mass transport time series.

Between 2002 and 2017, the US/German GRACE satellite mission provided monthly time series of gravity field models describing mass transport in the Earth system. These models are used by a broad scientific community to observe and analyze seasonal and sub-seasonal variations in the continental hydrological cycle, ice mass loss in Antarctica or Greenland, or surface and deep ocean currents. Since 2018, this time series has been extended by the GRACE Follow-on (GRACE-FO) mission and now spans more than 20 years. GRACE-FO was jointly realized and now operated in NASA/GFZ partnership.

The project G-MONARCH is investigating to what extent gravimetric methods can contribute to a better understanding and quantification of hydrological processes and storages in high-alpine catchments.

The GENESIS-D project, funded by the DLR space agency, is preparing the German scientific community to analyse the data from a future ESA ‘Space Tie’ satellite mission.

The International Centre for Global Earth Models (ICGEM) provides global Earth gravity field models and related data products to the international user community. The aim of the SAMDAT project is to extend and modernise the ICGEM service, including the existing database and the integrated calculation and visualisation services.

The Issyk Kul Observatory in Kyrgyzstan is used to monitor the quality of satellite radar altimetry in order to accurately measure sea level changes.

Our monitoring stations are a central element in the observation of processes in the Earth system. The stations are used worldwide, whether at the equator or at an altitude of 4000 m.

Central Asia is a hotspot of climate change and is characterized by increasing water scarcity. We are researching various aspects of these processes.

The Project Hydrometeorological Monitoring develops, builds and operates a network of monitoring stations for recording meteorological, hydrometeorological and climate changes in Central Asia.

In our section, highly precise orbits are routinely calculated for the Sentinel satellites of the Copernicus Earth Observation Programme of the European Commission and the European Space Agency (ESA).

In our section, the highly precise baseline determination between the two radar satellites TanDEM-X and TerraSAR-X is carried out on behalf of the DLR. These satellites fly in close formation and enable three-dimensional mapping of the Earth's surface with unprecedented accuracy.

GFZ operates the Tracking, Occultation and Ranging Payload (TOR) on the German radar satellite missions TerraSAR-X and TanDEM-X under an agreement between DLR and GFZ.

The project „Accurate long distance optical time transfer from ground to ground via a satellite link“ is part of the DFG Research Unit 5456 "Clock Metrology: Time as a New Variable in Geodesy". The RU aims to introduce "time coherence" as a new connecting variable for geodetic measurement techniques in order to help defining the International Terrestrial Reference Frame accurately in the millimeter range as required by the Global Geodetic Observing System (GGOS).

At GFZ, highly precise satellite orbits are calculated for both GPS and Low Earth Orbiting (LEO) satellites. These orbits are essential for the processing of GPS radio occultation data and their use in operational weather forecasting as well as for a better understanding of the ionosphere.

The "ADS - Harmonised Radar Altimeter Data" project collects and standardises satellite-based radar altimeter data from the last 40 years. This consistent water level data forms the basis for answering a wide range of questions from the ocean to the coasts and inland waters.

The project "COLSATI - Coastal sea level dynamics monitored by satellite altimetry and tide gauges" uses GNSS referenced tide gauge data from the North Sea coast to determine the accuracy and stability of current radar missions. The aim is to consolidate the trend estimates and investigate the dynamics of the coastal water level.

The flooding of Jakarta is often cited as an example of the consequences of rising sea levels. We are therefore looking at sea level changes and subsidence in Southeast Asia.

The project "Ready for SWOT - Application at GFZ" lays the foundations for the use of data from the innovative Surface Water and Ocean Topography (SWOT) mission. It explores the possibilities offered by SWOT for the investigation of coastal areas and inland waters in Central Asia.

The GRAV4GEO project aims to expand the resolution of currently available global gravity field models beyond their current limits using a forward gravity modelling technique that incorporates high resolution digital elevation and bathymetry models together with a laterally varying density model.

The project assesses the benefits of Next-generation Global Navigation Satellite Systems (NextGNSS) constellations beyond current GPS, GLONASS, Galileo, or Beidou for various key geodetic objectives, all of them meeting the requirements defined by the Global Geodetic Observing System (GGOS).

Laser retroreflectors have been or are being manufactured at the GFZ for various low Earth orbiting satellites in order to realise a GNSS-independent technology for orbit determination by means of Satellite Laser Ranging.

The MCGS project is developing particularly cost-effective, compact, low-power, GNSS-based measurement systems for geoscientific and engineering applications.

Ny-Ålesund is a research centre on Spitsbergen. The emission of radio waves is here generally limited to the bare minimum, in order to protect the many sensitive measuring devices on site, and even prohibited by the authorities in the 2-32 GHz frequency range. In the RSM-NYA project, the most important frequency ranges used locally are monitored and visualised via a web-based data portal.

Future generations of European global navigation satellite systems are expected to take advantage of recent breakthroughs in optical clock and optical data communication technology, progressions in atom interferometry and new concepts for autonomous spacecraft operations. Within project ADVANTAGE innovative architectures for future navigation systems are envisaged, designed and developed with wide ranging benefits for society, industry and science.

The project "High-frequency sea level altimeter data for the validation of GRACE ocean-dealiasing products" uses daily altimeter data to validate GRACE AOD-1B products.

The overall objectives of EGSIEM are a) to deliver the best time-variable gravity products for applications in Earth and environmental science research, b) to reduce the latency and to increase the temporal resolution of the gravity and related mass redistribution products, and c) to develop gravity-based indicators for extreme hydrological events and demonstrate their value for flood and drought forecasting and monitoring services.

GFZ/Section 1.2 is cooperation partner of the EU project FAMOS (Finalising Surveys for the Baltic Motorways of the Sea). FAMOS comprises all aspects of hydrographic surveying in the Baltic Sea Hydrographic Commission (HSHC) and the Baltic Marine Environment Protection Commission (Helsinki Commission – HELCOM).

GFZ-1 was the first GFZ satellite, designed for use in the field of satellite geodesy, equipped with laser ranging systems. The sperical satellite was used for determination of variations in the rotational characteristics of the Earth, for precise position determination and for the measurement of Earth's gravity field.

GGOS-SIM is a joint project with the Technische Universität Berlin (TUB) that aims at providing a tool for assessing and improving the quality of the International Terrestrial Reference Frame (ITRF). For this GGOS-SIM simulates the modern space geodetic techniques DORIS, GNSS, SLR, and VLBI, and the impact of new sites, co-locations, local ties, and technical improvements.

As the climate continues to warm, glaciers are retreating further and further. They often leave behind lakes that can suddenly erupt. The water stored in them poses a great danger to the population living below these lakes.

GNSS receivers now make it possible to determine heights with great precision in real time. We have installed this technology on buoys in various projects. This enables us to detect tsunamis on the ocean or to obtain information about water levels in rivers.

Tide gauges on the coasts have been providing reliable information about the rise and fall of sea levels for over 100 years. These time series enable us to observe long-term changes in sea level, but in recent decades also to detect tsunamis.

The Earth explorer satellite GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) is the first satellite mission within the framework of the Living Planet Programme of ESA. This satellite mission is mapping the Earth's gravity field on global scales with a spatial resolution of approx. 100 km which is considerably more precise than all gravity satellite missions to date.

GRACE is a joint project between the National Aeronautics and Space Administration (NASA) and the Deutsches Zentrum für Luft- und Raumfahrt (DLR). The mission has been proposed in 1996 jointly by the University of Texas at Austin, Center for Space Research (UTCSR), the German Research Centre for Geosciences (GFZ) and the Jet Propulsion Laboratories (JPL) in Pasadena.

The project "Influence of orbit modelling on sea level" investigates which orbit models provide the most consistent water level data and quantifies differences on seasonal to decadal time scales.

China and its coasts are experiencing both a rapid rise in sea levels and the subsidence of major cities on the coasts. Both effects together pose a danger to the coastal population.

The Lense-Thirring-Effect can be derived, for example, from the nodal drifts of the LAGEOS satellites with the help of the GRACE gravity field models.

As part of the GITEWS project, an automatic GNSS data processing system was developed at the GFZ for the Indonesian Tsunami Early Warning System INATEWS in Jakarta, Indonesia.

As part of the GITEWS project, an automatic system for determining ground motions and co-seismic deformations was developed at the GFZ. This supports a quick answer to the important question in tsunami early warning: whether an earthquake has triggered a tsunami.

Within the GITEWS project, GNSS reference stations have been developed at GFZ for applications in the field of early warning systems. 10 of these stations have been installed in Indonesia and integrated into the Indonesian INATEWS Tsunami Early Warning System.

Graphical user interfaces for GNSS-based technologies are the visible parts of programmes that enable users to operate GNSS devices and systems for processing GNSS data. For special monitoring tasks (e.g., in early warning), corresponding customised graphical user interfaces have been created at the GFZ.