A Novel Real-Time Echo Restoration Algorithm From Ambiguous Signals in High-PRF SAR

Real-time echo restoration from signals containing range ambiguities is a technique challenge for high pulse repetition frequency (PRF) synthetic aperture radar (SAR). In this letter, to ensure real-time processing, a novel azimuth phase coding (APC) scheme is utilized to realize the processing of raw data in groups, which is conceived for a conventional SAR system. Meanwhile, an advanced fast algorithm is proposed to further decrease the computational complexity of the restoration processes. The proposed scheme is validated by the simulated point-like and distributed targets SAR data. The quantitative analysis results show that the ambiguous signal can be at least suppressed by 40 dB and the image average range ambiguity separation error (RASE) is less than -60 dB. Finally, compared with some conventional methods in computational complexity and memory cost, the results illustrate that the processing efficiency has been significantly improved and the memory resource occupation has been significantly reduced. Particularly, the proposed fast algorithm improves the computational efficiency by about 80 times.