A golden age for spaceborne SAR systems

Spaceborne Synthetic Aperture Radar (SAR) is the only imaging sensor technology that can provide all-weather, day-and-night and high-resolution images on a global scale. Today, SAR data are used for a multitude of applications ranging from geoscience and climate change research, environmental monitoring, 2-D and 3-D mapping, change detection, 4-D mapping (space and time), security-related applications up to planetary exploration. With the launch of the SAR satellites TerraSAR-X and TanDEM-X, COSMO-SkyMed constellation, Radarsat-2 as well as Sentinel-1a a new class of SAR satellites was introduced providing images with resolution in the meter regime. A paradigm shift is however taking place in spaceborne SAR systems. By means of the development of new digital beamforming and waveform diversity technologies in combination with large reflector antennas, future SAR systems will outperform the imaging capacity of current systems by at least one order of magnitude. This paper will provide an overview of the state of the art in spaceborne SAR technologies and applications, and will describe the innovative techniques and technologies that will shape its future development.