基于斜距等效的弹载双基前视SAR相位空变校正方法

发布时间：2018-09-01 10:29

【摘要】：作为一种特殊的新型双基合成孔径雷达(SAR)成像模式,弹载双基前视SAR(Missile-borne Bistatic Forward-Looking SAR,MBFL-SAR)可实现末端俯冲段前视2维成像。然而距离历程中双根号及高阶项的同时存在导致其2维频谱难以有效获得,且收发平台高度的不断变化和运动方向的不同造成回波相位的空变特性。该文提出一种基于斜距等效的MBFL-SAR相位空变校正方法。该方法利用修正的双曲线斜距模型将具有双根号和高阶项的距离历程表达式等效并简化为单根号斜距表达形式,进而利用驻定相位原理求得其高精度2维频谱;随后通过多项式高阶拟合的方法精确补偿频谱中空变的相位项,完成场景成像聚焦。该方法可高精度成像且相对于传统方法聚焦性能有显著提高。最后,通过仿真验证了所提方法的有效性。
[Abstract]:As a special new bistatic synthetic aperture radar (SAR) imaging mode, the bistatic forward looking SAR (Missile-borne Bistatic Forward-Looking SAR,MBFL-SAR) can realize the 2-D forward imaging of the terminal subduction segment. However, the existence of dual root and higher order terms in the distance history leads to the difficulty of obtaining the two-dimensional spectrum effectively, and the spatial variation of echo phase is caused by the constant change of the height of the transceiver platform and the difference of the direction of motion. In this paper, a MBFL-SAR phase space change correction method based on oblique distance equivalent is proposed. By using the modified hyperbolic oblique distance model, the distance history expression with double root sign and higher order term is equivalent and simplified to a single root sign oblique distance expression, and then the high-precision two-dimensional spectrum is obtained by using the stationary phase principle. Then the phase terms of the frequency spectrum are accurately compensated by polynomial high order fitting to complete the scene focus. This method can be used for high accuracy imaging and can improve the focusing performance compared with the traditional method. Finally, the effectiveness of the proposed method is verified by simulation.
【作者单位】：西安电子科技大学雷达信号处理国家重点实验室;
【基金】：国家自然科学基金(61001211,61303035,61471283) 中央高校基本科研业务费(K5051202016)~~
【分类号】：TN957.52

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