摘要
提出了一种球面波照射下获得飞行器类目标远场RCS的变换算法。根据ISAR成像中目标反射率空间分布特性不随测试状态改变,建立了多散射中心模型;针对隐身目标自身高度较小、在竖直面上满足远场条件的特点,将入射球面波等效为柱面波照射;以目标像作为二次辐射源,导出了远近场之间的依赖关系式;利用目标全角域近场散射信息进行外推,获得了远场条件下各个角度的RCS值。该算法采用对频率求导的方法,降低了公式简化中的误差,又满足了步进频率系统的测试要求。仿真和实验表明算法准确有效。
An extrapolation algorithm from near-field scattering data to obtain RCS of aircraft is presented. According to the fact that objective reflectivity spatial distribution is unchanged with measurement state in ISAR imaging, here the multi-cattering center model is built at the very beginning. Then, the height of stealth target is always short, and the far-field condition can easily be satisfied on vertical plane, so the incident spherical wave is equivalent to cylindrical wave. Once more, the relationship between far-field and near-field is deduced by regarding image of the target as secondary radiation source. Finally, the RCS of target can be obtained with the scattering data of near-field extrapolated at full angular aspect. Taking derivative of the near-field data with respect to frequency, the error can be reduced in simplifying formula, and it meets the requirement of stepped-frequency system. The results of simulation and experiments show that the algorithm is precise as well as effective.
出处
《电波科学学报》
EI
CSCD
北大核心
2009年第1期39-42,共4页
Chinese Journal of Radio Science
关键词
RCS
近场
远场
多散射中心模型
二次辐射源
RCS
near-field
far-field
multi-scattering center model
secondary radiation source
