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

Abstract

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 than 4 dB, verifying the effectiveness of the modeling methods of simulating electromagnetic scattering characteristics of non-uniform plasma coated targets.