一种时域去走动的四阶模型SAR成像方法

针对大斜视SAR回波耦合性强问题，从提高斜距模型近似精度和距离徙动校正精度两方面对SAR成像进行了研究，推导了一种四阶SAR成像算法模型。首先为了提高模型近似度，将斜距展开到四次项，然后为了将距离向和方位向进行初步解耦，在时域进行走动补偿，通过级数反演法将信号转到二维频域进行距离弯曲校正，方位匹配滤波后得到聚焦后的SAR图像。该方法流程简单，便于实时处理。仿真结果表明，该方法具有较强斜视处理能力，取得了较高的成像分辨率。

Method of 4th-order model SAR imaging with range-migration in time domain

Considering that the coupling of high squint SAR echoes is strong, this paper studies SAR imaging in terms of enhancing the approximation accuracy of high squint model and correction accuracy of range-jittery, and derives a model for 4th-order SAR imaging algorithm. In this scheme, the squint range is first expanded to the fourth power term for enhancing the approximation degree, and the compensation of range-migration is done in time domain, for the preliminary decoupling of range and azimuth. The signals are transferred to the bi-dimensional frequency domain for performing the correction of range curvature, by using the reversion method of series, and the focused SAR image can be achieved by the azimuth match filtering. This proposed method is of easy flow and real-time processing. The simulation results show that the method is of higher capability of squint mode process-ing and imaging resolution.