Radar Concepts Department

Radar Concepts
Mission Tandem-L
The Tandem-L mission is a satellite mission currently proposed by the Institute for the global observation of dynamic processes on the Earth's surface - in a quality and resolution never before achieved.
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The Radar Concepts department develops innovative techniques, technologies and information retrieval algorithms for future radar remote sensing systems, missions and applications. The research areas cover a wide spectrum, including the investigation of new SAR imaging modes and instrument architectures based on digital beamforming and multi-aperture signal processing, the design and analysis of bistatic and multistatic satellite systems and missions, and the quantitative retrieval of bio/geo-physical parameters from interferometric and polarimetric SAR data. Further key topics are wide-area traffic monitoring, end-to-end simulation of SAR systems and missions, modeling of propagation effects in the ionosphere, and the development of new sensor concepts for both terrestrial and extraterrestrial missions and applications.

Besides its research activities, the Radar Concepts department provides notable support to the Satellite SAR Systems department in view of the implementation and conduction of approved SAR missions. Examples are the development and operation of the science service segment, the definition, implementation and validation of algorithms for higher-level products, and the assistance in various engineering aspects related to mission and instrument design and performance. The Radar Concepts department is moreover involved in a large number of national and international third-party studies and plays an active role in the definition of ESA missions, e.g., via the participation in the BIOMASS Mission Advisory Group (MAG) or by various proposals for future Earth Explorer Missions.

The department’s activities are guided by its strategic focus on the conception, development and design of pioneering radar missions for cutting-edge remote sensing applications. A recent example is the development of the Tandem-L mission concept with its highly innovative radar satellites providing a number of unique Earth observation products. The long-term vision is the development of an intelligent, reconfigurable, scalable and affordable network of cooperating radar satellites, which will serve together as a global real-time microwave observatory of our planet Earth. Such an observatory satisfies not only the ever-increasing user demands regarding operational availability, timeliness, resolution and data quality, but it paves also the way for new and revolutionary applications and services.

Research and Project Groups

NewSpace SAR

The NewSpace SAR group develops disruptive and cost-effective SAR solutions for frequent and enhanced Earth monitoring, based on the exploitation of small satellites, distributed and fractionated concepts, waveform diversity, and cognitive approaches. The group aims at establishing the foundation for an application-driven system design, spreading the on-going NewSpace revolution to SAR remote sensing and posing the basis for future Earth observation missions that will yield remarkable societal benefits. The group continuously interacts with other departments and groups of the Institute, other DLR Institutes, as well as external organizations. The group is involved in studies of the European Space Agency (ESA) and the European Commission (EC), has a research collaboration with the NASA Jet Propulsion Laboratory (JPL), and has recently started a cooperation with the New Zealand Space Agency/University of Auckland. In particular, this cooperation concentrates on research related to the design and the development of a low-cost SmallSats SAR to address dedicated applications of interest for the New Zealand Government, such as the monitoring of fishing vessels and measurement of surface deformations using persistent scatterers.

Information Retrieval

The Information Retrieval group focuses on the development, implementation, validation and calibration of new algorithms and techniques for the derivation of innovative higher-level information products from actual and future spaceborne radar missions. The broad expertise and experience of the group allows for a wide spectrum of activities. One central task is the development of innovative processing techniques as well as modelling and inversion algorithms for the generation of new information products from multi-parameter SAR measurements and the definition and implementation of the associated performance analysis models. Of the same importance is the development of innovative techniques and methods for the calibration of complex instrument modes and data sets of future SAR missions. The Information Retrieval group leads and contributes to several national and international studies and is active in the science and science advisory teams of national (as TanDEM-X and Tandem-L), European (as BIOMASS and SAOCOM-CS) and international (as ALOS, GEDI and NISAR) SAR missions and mission proposals.

SAR Missions

The SAR Missions group develops and elaborates proposals for future mono-, bi- and multistatic radar missions. The high-level user requirements are analyzed and translated into a set of detailed mission requirements, from which appropriate mission concepts are derived. The mission definition relies on in-depth investigations and simulations regarding the end-to-end SAR system and mission performance taking into account acquisition frequency and coverage, orbit and satellite formation geometry, etc. Implementation trade-offs are assessed and the mission design is optimized by implementing global-scale performance models, which are used to simulate and evaluate the performance of higher-level products for different acquisition timelines. The new mission concepts employ also highly advanced SAR imaging techniques and technologies like multi-channel receiver systems, digital beamforming, and multistatic satellite formations. The research activities encompass novel algorithms for bi- and multistatic SAR focusing and synchronization, distributed and fractionated SAR systems like MirrorSAR, new mission concepts in medium Earth and geosynchronous orbits, and experiments with TerraSAR-X and TanDEM-X to demonstrate new SAR imaging modes and applications. With its unique know-how, the SAR Missions group is involved in a large number of third-party studies and it has elaborated over the past years a number of bi- and multistatic mission proposals like PicoSAR, SESAME and IRIS. It furthermore supports the Satellite SAR Systems department with dedicated investigations in the areas of bistatic synchronization, end-to-end simulation and mission performance assessment.

SAR Techniques

The SAR Techniques group develops innovative radar instrument concepts for SAR satellites. The primary focus is on the conception, design, analysis, optimization and demonstration of innovative digital beamforming and multiple-input multiple-output (MIMO) radar techniques, modes and architectures that pave the way for future SAR missions with unprecedented imaging capabilities. The group has more than fifteen years of experience in all aspects of radar instrument analysis and it has developed a suite of sophisticated software tools to analyze the performance of SAR systems. To experimentally test and verify new SAR techniques and applications, a modular ground-based MIMO radar demonstrator has been developed, which is highly reconfigurable. A research focus is the development of multi-aperture SAR processing algorithms, both for ground-moving target indication and high-resolution wide-swath SAR imaging. Further research activities encompass the calibration and data reduction in multichannel SAR systems and the development of new hybrid, adaptive and cognitive SAR systems. With its know-how and experience in all aspects of SAR instrument design, the SAR techniques group is involved in a large number of third-party projects and supports the Satellite SAR Systems department during the development of Tandem-L.

Pol-InSAR

The main objective of the Polarimetric SAR Interferometry (Pol-InSAR) group is the development, implementation and validation of innovative algorithms and methods for the inversion of bio- and geophysical parameters from Pol-InSAR data, acquired in repeat- or single-pass, mono- or bistatic, single- or multiple-baseline configurations. The coherent combination of SAR interferograms at different polarizations and baselines by means of Pol-InSAR has been developed from the very beginning within this group and is today an established technique for the estimation of the structural parameters of volume scatterers such as forests, snow and ice. The development of inversion techniques and the validation of Pol-InSAR applications are performed in close collaboration with international experts and institutions. Further research topics are the application of SAR polarimetry and bistatic SAR polarimetry. The group proposes, designs, supervises and evaluates scientifically air- and spaceborne experiments necessary for the validation of the developed methodology/procedures in the framework of dedicated campaigns. It contributes also to a number of national and international science development studies and supports the science of ongoing and future missions such as TerraSAR-X, TanDEM-X, Tandem-L or BIOMASS through active participation and/or the coordination of the science teams.

Contacts

Prof. Dr.-Ing. Gerhard Krieger

Head of Deparment: Radar concepts
Microwaves and Radar Institute
Radar concepts
Muenchener Strasse 20, 82234 Wessling
Germany