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| Robust Channel Mismatch Estimation in Multichannel HRWS SAR Based on Range Spectrum Analysis |
| FANG Chao① LIU Yanyang② SUO Zhiyong① LI Zhenfang① CHEN Junli③ |
①(National Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, China)
②(Shanghai Institute of Satellite Engineering, Shanghai 201109, China)
③(Shanghai Academy of Space Technology, Shanghai 201109, China) |
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Abstract In multichannel High-Resolution and Wide-Swath (HRWS) Synthetic Aperture Radar (SAR) systems, channel amplitude and phase mismatches would degrade the performance of azimuth ambiguity suppression as well as range sampling mismatches. To address this problem, a robust estimation method based on range spectrum analysis is proposed in this letter. The method includes two steps: firstly, by exploiting the interferometric phases between the range spectrums of adjacent channels, the proposed method can robustly estimate range sampling mismatches by the combination of phase unwrapping and a weighted least squares fitting. Secondly, based on the theory of spatial cross correlation, an accurate Doppler centroid and phase mismatches could be obtained from constant phases between adjacent channels. Compared with traditional methods, the proposed method overcomes the effect of phase wraps and jumps on polynomial coefficient estimation. It not only improves the robustness of parameter estimation but also can simultaneously obtain the Doppler centroid and phase mismatches. Experimental results based on airborne real data and simulated data validate its effectiveness of the proposed method.
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Received: 24 October 2017
Published: 10 May 2018
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| Fund:The National Natural Science Foundation of China (61471276, 61601298, 61671355, 41371439) |
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Corresponding Authors:
SUO Zhiyong
E-mail: zysuo@xidian.edu.cn
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