Digital beamforming in elevation for spaceborne HRWS SAR based on sparse DOA estimation

ABSTRACT

A digital beamforming (DBF) algorithm in elevation for spaceborne high-resolution and wide-swath synthetic aperture radar (SAR) systems is presented. According to the imaging geometry, a generalized signal model for SAR systems of multiple elevation channels is studied. The signals received by the channels are regarded as that coming from different direction-of-arrive (DOA) angles. Then, the key procedure for DBF is transformed to DOA estimation. Considering the sparsity of the received signals in spatial domain, the sparse-based DOA estimation algorithm is adopted. After obtaining the DOA angles, the weighted vector for DBF is achieved. Compared to the conventional algorithms, the proposed algorithm has no requirement for the number of snapshots and is more robust to signal-to-noise ratio. Finally, the effectiveness of the proposed algorithm is confirmed in simulations.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 61601090, 41471361, 41371439], Fundamental Research Funds for the Central Universities [grant number ZYGX2015J115], Key Laboratory of Satellite Mapping Technology and Application, National Administration of Surveying, Mapping and Geoinformation [grant number KLSMTA-201507] and Shanghai Aerospace Science and Technology Innovation Fund [grant number SAST2016037].