A Glimpse into the Future of Spaceborne SAR
Prof. Alberto Moreira
In a changing and dynamic world, high-resolution and timely geospatial information with global coverage and access is becoming increasingly important. Spaceborne radar plays an essential role in this task, as it is the only sensor technology which provides high-resolution imagery on a global scale independent of the weather conditions and sunlight illumination.
This talk will first provide an overview on the state of the art in spaceborne synthetic aperture radar (SAR). One prominent example is the TanDEM-X mission, the first bistatic radar in space consisting of two satellites in close formation flight. TanDEM-X has already generated a global digital elevation
model (DEM) of the Earth with unparalleled quality and resolution. A second edition of a global DEM, called “Change DEM” is being generated and will become available in late 2022. All topographic changes occurred between the two DEM acquisitions will become available for the first time on a global scale.
The second part of this talk describes the paradigm shift that is taking place in spaceborne SAR systems using multi-channel concepts with digital beamforming. The rapidly growing user community poses demanding requirements for data with higher resolution, larger coverage and higher timeliness. This is driving the development of new technologies for achieving high-resolution wide-swath (HRWS) imagery for the global monitoring of dynamic processes on the Earth’s surface. At the same time, low-cost, lightweight systems based on NewSpace concepts are being implemented with the objective to image small areas with a very short revisit time. Last but not
least, the combination of full-fledged SAR systems with disruptive NewSpace SAR concepts offers a wealth of new system approaches for multistatic SAR missions with enhanced imaging capabilities. One example is the HRWS mission with the MirrorSAR concept which consists of a main X-band
satellite and three small receive-only satellites using the MirrorSAR concept of a space transponder. The HRWS MirrorSAR mission will provide high-resolution imagery with a benchmark 20 to 100 times higher than TerraSAR-X in terms of swath width and spatial resolution. Furthermore, a global DEM
with 4 m x 4 m sampling and 2 m height accuracy will be generated on a yearly basis for a variety of scientific, commercial and governmental applications.
The ultimate goal for spaceborne SAR remote sensing is the deployment of a space-based sensor web consisting of a radar observatory with a constellation of satellites which is able to provide realtime geospatial information as an essential contribution to solving societal challenges of global dimension related to climate change, sustainable development, resource scarcity, land use, food
security, environmental protection, disaster monitoring and management as well as civil security.