Matrix pencil method for topography‐adaptive digital beam‐forming in synthetic aperture radar

Abstract Spaceborne synthetic aperture radar (SAR) with digital beam‐forming (DBF) in elevation uses very sharp time‐variant antenna beams to improve the signal‐to‐noise ratio (SNR) and range ambiguity‐to‐signal ratio. In acquisition scenarios of imprecisely known Earth topography, however, antenna pointing might be mismatched with surface geometry. To handle this issue, it is suggested that preprocessing is applied to DBF to determine the angle of the incident echo signal on the planar antenna array. The authors derive a method that estimates the direction of arrival on the acquired raw data with high accuracy in real time. The method is based on the matrix pencil, which is a common approach in mathematics for solving linear equation systems. As a key innovation, this paper describes further improvements and adaptions to SAR scenarios and provides a possible concept for practical implementation. For proof of concept, a series of different simulation tasks is performed.