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A Method of PRF-Ambiguity Resolution Based on Range Frequency Domain

Synthetic aperture radar (SAR) image formation is an alternative approach to remote earth observation that provides several advantages over visible/infrared sensing technology. So SAR is currently used for a large number of applications. For high resolution SAR, the determination of the Doppler centroid is indispensable. When the squint angle is too big, the Doppler centriod is bigger than PRF which results in ambiguities. The method proposed in this paper starts from range frequency domain, firstly it splits many blocks in range, secondly it estimates fuzzy Doppler centriod using CDE, then the curve changed by range frequency can be derived by using polynomial curve fitting, lastly ambiguities and exact Doppler centriod can all be acquired. The effectiveness of this method has been demonstrated by simulation and measured data imaging experiment. Meanwhile the method introduced in this paper causes only low computational load.