多频段典型地表的双站雷达散射回波预测

Multi-band Bistatic Radar Echo Prediction from the Terrian Surfaces

双站雷达在反隐身、超低空防御方面具有独特优势,但双站测量装置较为复杂,地表参数的准确获取工作耗时耗力,且精度难以保证,地表双站雷达散射数据极其匮乏。为解决上述问题,该文以L/S/X/Ku波段裸土、水泥地和粗糙沙地后向散射实测数据为例,忽略地表的精细结构,采用等效面散射模型和遗传算法反演了各地表的等效介电常数和粗糙度参数,获取其等效参数统计特征,实现对地表双站雷达散射回波的预测。结果表明:该等效面散射模型保证了地表的后向和双站散射回波预测精度;地表双站雷达散射回波随入射波频率的增大而增大;随散射角的增大先增大而后减小,并在镜像方向出现最大值;随散射方位角的增大,地表散射回波先减小而后增大,HH极化双站散射回波的最小值一般出现在90?方位角处,而VV极化双站散射回波的最小值位置随入射角的增大从90?方位角向小角度方向偏移,并与入射波频率、地表湿度以及粗糙度参数相关,该双站散射特性可用于地表参数的反演以及目标的反隐身研究。

Bistatic radar has an advantage in the anti-stealth and low altitude defense, but the bistatic scattering data measured from the terrian surface are extremely scarce. To solve this problem, the genetic algorithms and the backscattering data from the soil, concrete and the sand surface in L/S/X/Ku band are used to retrieve the effective permittivity and the roughness parameters of the land, and then the bistatic scattering data are predicted. The research above proves that the land equivalent surface scattering model is effective. The bistatic scattering echo increases with frequency, and it first increases and then decreases along with the scattering angles, first decreases and then increases along with the scattering azimuth angles. The minimum value of the bistatic scattering echo always appears in the 90 degree azimuth angles for the HH polarization, and it shifts from 90 degree azimuth angles to the small angle direction for the VV polarization. And also it is related to incident frequency, the moisture and the roughness of land. The bistatic scattering characteristics of land surface can be used for the anti-stealth research and the inversion of the land parameters.