一种改进的补偿因子区域不变CS算法及Simulink模型建模

An improved chirp scaling algorithm featured by invariance of compensation factors in a region and its modeling by Simulink

摘要:

相位补偿因子、距离向补偿因子和方位向补偿因子的产生是合成孔径雷达实时CS（Chirp Scaling，调频变标）算法中的关键。针对一种现有的补偿因子区域不变CS算法进行了改进，对于更新步长内各单元的统一补偿因子，采用该区域内所有单元频率平均值对应的补偿因子，代替原来使用的第一个单元对应的补偿因子，使得最终的补偿结果相比于原有算法更加均匀，计算量与原有算法相当。经过Matlab仿真验证，改进算法的成像指标得到提升。为便于生成FPGA代码，采用Simulink工具搭建了用于生成改进算法中三种补偿因子的模型。将Simulink模型输出的代码加载到Vivado软件中，对Vivado输出的补偿因子与由Matlab输出的精确补偿因子进行了对比，精度满足要求，验证了所搭建Simulink模型的准确性。

Abstract:

The generation of the phase compensation factor, the range compensation factor and the azimuth compensation factor are the key in the real-time CS (chirp scaling) algorithm of synthetic aperture radar. An existing CS algorithm featured by the invariance of compensation factors in a region is improved. For the unified compensation factor in units inside the update step size, the compensation factor corresponding to the average frequency of all units in a region is used to replace the compensation factor corresponding to the first unit, which makes the final compensation result using the improved algorithm is more uniform than that of the original algorithm. The computation load of the improved algorithm is equivalent to that of the original algorithm. Through Matlab simulation, the imaging performance of the improved algorithm is improved. In order to facilitate the generation of FPGA code, the Simulink tool is used to build a model for generating three compensation factors used in the improved algorithm. The output code of Simulink model was loaded into Vivado software. The compensation factor outputted by Vivado is compared with the accurate compensation factor outputted by Matlab. The output generated by Vivado meets the accuracy requirement, which verifies the correctness of the built Simulink model.