An Improved Real-Time Echo Separation Processing Scheme in Intermediate Frequency Domain.

Space-time waveform-encoding (STWE) synthetic aperture radar (SAR) has great potential to improve the performance of the future spaceborne SAR system. With the aim of solving the problem of overlapped echoes, one effective approach involves the use of digital beamforming (DBF) in elevation combined with the null-steering techniques. However, the traditional real-time echo separation scheme with single-null-steering techniques occupies huge digital resources. In this letter, a novel real-time echo separation processing scheme in intermediate frequency domain is proposed to overcome the disadvantage of the conventional scheme. Based on the 2-D simulation results, the proposed scheme has the same accuracy of separating the overlapped echoes as the traditional scheme. The detailed analysis of the system complexity indicates that the proposed scheme can greatly reduce the resource occupation. Moreover, the effectiveness of the proposed scheme is further verified and demonstrated by the experimental results on the X-band 16-channel DBF-SAR system. [ABSTRACT FROM AUTHOR]