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Improved NLCS Algorithm Based on Ellipse Model for One-stationary Bistatic SAR with Large Baseline |
ZHONG Hua HU Jian ZHANG Song SUN Minhong |
(School of Communication Engineering, Hangzhou Dianzi University, Hangzhou 310018, China) |
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Abstract In One-Stationary Bistatic Synthetic Aperture Radar (OS-BiSAR) imaging, imprecise description of 2-D range-azimuth space-variant property usually leads to deterioration of final SAR image rapidly. In order to solve this issue, a new ellipse model is proposed to precisely describe range-azimuth space-variant property of OS-BiSAR with large baseline, and an improved Non-Linear Chirp Scaling (NLCS) algorithm is also derived based on this model. First, a phase de-ramp operation is performed to remove the linear Range Cell Migration (RCM) and Doppler centroid in range frequency domain. Then, the residual RCM and high order range-azimuth coupling terms are removed. Thirdly, a new ellipse model is established to describe range-azimuth space-variant property of OS-BiSAR, and then the azimuth frequency modulation rate of space-variant echo is analyzed. Moreover, azimuth scaling function of NLCS and azimuth compression factors are re-derived. Theoretical analysis and simulation results show that the proposed model not only reveals the property of 2-D azimuth-variant in OS-BiSAR, but also provides a precise analytical expression to depict the 2-D range-azimuth space-variant property of OS-BiSAR. Furthermore, simulation results validate that the improved NLCS algorithm based on this new model has high imaging performance.
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Received: 30 September 2016
Published: 14 December 2016
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Fund: The National Natural Science Foundation of China (61301248, 61271214), Chinese Innovation Foundation of Aerospace Science and Technology |
Corresponding Authors:
ZHONG Hua
E-mail: hzhong@hdu.edu.cn
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