一种提高海洋SAR定位精度的方法
A Means of Improving Accuracy of Positioing for Ocean SAR
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摘要: 在无参考点海洋SAR定位方法中,多普勒中心频率估计对定位精度有着重要的影响.该文从理论和仿真两个角度研究了信噪比对多普勒中心频率估计的影响,给出了多普勒中心频率和信噪比的理论及仿真关系曲线.在此基础上针对海洋回波信号较弱的特点,在海洋SAR系统设计中增加一个多普勒测量模式.和普通成像模式相比,该模式通过降低带宽的方式来提高回波的信噪比,从而提高了定位精度.Abstract: Estimation of Doppler central frequency has an important effect to accuracy of fixed position in the fixing approach with no reference points for ocean SAR. The effect of Signal-Noise-Ration (SNR) to the estimation of Doppler central frequency has been studied using theoretical method and simulation technique, and results are given in curves. Based on above results, a Doppler measurement mode is adopted in the design of ocean SAR. Compared to common imaging mode, this mode increases SNR of ocean echo by decreasing the bandwidth, then accuracy of fixed position can be improved.
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