First Spaceborne Demonstration of Digital Beamforming for Azimuth Ambiguity Suppression

Over the past years, the use of multiple antenna apertures combined with digital beamforming (DBF) has been spotlighted as a promising solution for the fundamental restriction for high-resolution and wide-swath spaceborne synthetic aperture radar (SAR) imaging. In this paper, we present the first spaceborne experiment of a DBF technique on receive, using the TerraSAR-X dual receive antenna mode. For this experiment, we implemented a DBF module, which includes the reconstruction filter as a digital beam former and associated signal processing for calibration and channel balancing. The experimental results exhibit the successful ambiguity suppression capability of the DBF and validate the high potential of the DBF both for advanced future and current SAR systems.