高超声速类HTV2模型全目标电磁散射特性实验研究

Experimental investigation on all-target electromagnetic scattering characteristics of hypervelocity HTV2-like flight model

针对临近空间高超声速飞行器目标探测与识别研究的需求,开展了高超声速飞行器非均匀等离子体电磁散射特性模拟测量研究.利用弹道靶设备发射高超声速类HTV2模型形成模拟的超高速复杂外形目标,弹道靶高精度阴影成像系统和雷达测量系统分别测量高超声速类HTV2模型姿态、全目标C波段/X波段电磁散射特性,获得了不同实验条件下模型全目标雷达散射截面积(RCS)等实验数据.研究结果表明:在不同实验状态下,包覆等离子体鞘套的高超声速类HTV2模型同一测量波段的RCS差别超过1个数量级,模型姿态角对包覆等离子体鞘套的高超声速类HTV2模型RCS影响较大,最大相差1个多数量级;在给定的实验条件下,模型尾迹C波段RCS远小于包覆等离子体鞘套的模型RCS,模型尾迹X波段RCS显著增强;高超声速类HTV2模型全目标C波段电磁散射能量主要分布在模型及其绕流区域, X波段电磁散射能量主要分布在模型及其绕流区域和等离子体尾迹区域.根据弹道靶实验条件,开展了包覆等离子体鞘套的高超声速类HTV2模型电磁散射特性数值仿真,仿真结果与实验结果之间的最大误差小于4 d B,验证了本文提出的非均匀等离子体包覆目标电磁散射特性建模方法的有效性.

According to the requirements for target detection and recognition of hypervelocity vehicles in near space,the simulation and measurement of corresponding electromagnetic scattering characteristics of non-uniform plasma generated by hypervelocity targets are conducted. A numerical calculation method with dynamic plasma parameters is developed and hypervelocity HTV2-like models launched by the ballistic ranges are used to simulate complex shape target flying at a hypervelocity velocity. The high-precision shadow imaging systems and radar measurement systems of the ballistic range are used to measure the model postures, the electromagnetic scattering characteristics of the whole targets and their flow fields in both C band and X band.The experimental measurement results of the radar cross section(RCS) of the models and their flow fields under different experimental conditions are obtained. The results show that the numerical simulation methods of unsteady high-temperature ionized air flow can be used to simulate the unsteady thermal chemical flow fields around the head and body of the simplified hypervelocity HTV2-like flight models. The electromagnetic scattering characteristics of the models and their plasma sheath differ by more than one order of magnitude under different experimental conditions. The total RCS of the model’s wake in the C band is much smaller than that of the model, and the total RCS of the model’s wake in the X band is significantly enhanced. The attitude angles of the models have great influence on their electromagnetic scattering characteristics and their RCSs with different attitude angles can differ by one order of magnitude. The electromagnetic scattering energy of the model in the C band is distributed mainly around the targets and their flow fields surrounding them. The X band electromagnetic scattering energy of the model is distributed mainly in the regions around the targets,surrounding flow fields and the wake flow fields. According to the experimental conditions of the ballistic range,the numerical simulation analyses of the electromagnetic scattering characteristics of the models and flow fields around them are carried out, and the maximum error between simulation and experimental results is less than4 dB, verifying the effectiveness of the modeling methods of simulating electromagnetic scattering characteristics of non-uniform plasma coated targets.