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In this article, a hypersonic target electromagnetic (EM) scattering echo model combined with the inhomogeneous zonal medium model (IZMM) and the classical scattering center model (SCM) is proposed with a distributed satelliteborne array radar as the detection platform. A parallel physical optics (PO) method is used for multiview inverse synthetic aperture radar (ISAR) imaging of a moving hypersonic target covered with plasma sheath based on the analysis of high-resolution range profile in the S-X ultrawideband range, reconstructing 2-D EM scattering echo data (the target) and motion compensation. The results show that the surface of the inhomogeneous plasma sheath flow field is an excitation layer with random and irregular fluctuation characteristics, which increases the false scattering centroid of the 1-D range profile of the hypersonic target and can interfere with and disrupt the radar localization of the target along the radial direction. In addition, shallow scattering of EM waves occurs in the plasma sheath, and the average signal intensity of the target can gradually reduce from 0.5 x 10⁻⁵ at 60 km and 20 Ma to 0.1 x 10⁻⁵ at 30 km and 20 Ma, with a fivefold weakening of the overall scattered echo signal. In particular, the faster the hypersonic target travels at 30-km altitude, the weaker the imaged scattered echo signal becomes, with the average intensity of the imaged signal weakening by approximately threefold from 15 to 25 Ma. This study provides considerable technical support and data assurance to establish a synthetic aperture radar (SAR) automatic target recognition (ATR) database, and the findings of this study can be used as a reference for fine-structure feature analysis of hypersonic targets for feature extraction and the classification and identification of targets.

Using the parallel physical optics method, the range profile of a hypersonic vehicle with an electrically large size covered by 1-D inhomogeneous plasma sheath was studied. In this article, under the condition of far-field approximation, the improved physical optical method of 1-D nonuniform plasma coating of the conductive target was applied to calculate the scattered electric field of the target at different frequencies; then, 1-D Fourier inversion of the scattered electric field was carried out to obtain the 1-D range profile of the target. Numerical results showed that the temperature and pressure changes inside the plasma will have an impact on the range profile of the aircraft, and the intensity of the range profile of the target is inversely proportional to the temperature and pressure. In addition, the flight Mach parameters of the target aircraft, which affect the 1-D range profile, were also analyzed. The results showed that the larger the flight Mach number, the easier it is to detect the target aircraft. Finally, it was found that the nonuniformity of the plasma significantly influenced the 1-D range profile of the coated target; the intensity value of the range profile of the target aircraft (covered by the plasma sheath) at different flight heights was significantly lower than that of the pure metal target, resulting in the so-called “stealth” effect. This research provides some methods for effectively measuring and controlling hypersonic vehicles in adjacent space and alleviating the interruption of reentry communication.

To investigate the electromagnetic scattering problem related to a foil in a turbulent hypersonic plasma environment, the scattering field formulas for hypersonic plasma turbulence were improved by applying the anisotropic power spectrum. Using the theory of electromagnetic scattering of a conducting object, the second moment of a conducting object's scattering field is obtained in the hypersonic plasma turbulence. Finally, the backscattering cross-section of the foil surrounded by the hypersonic plasma turbulence was calculated. The results showed that the fractal dimension led to an increase in the complexity of the hypersonic turbulent structure, and thus had a greater influence on the electromagnetic wave scattering. The scattering cross-section of the foil in the hypersonic turbulence decreases rapidly. Meanwhile, the anisotropic parameters in the model represent scale-dependent stretching of the turbulent eddy. As the anisotropic parameters of the turbulence increase, there will be less scattering of the hypersonic turbulence. At this point, the total scattering cross-section of the foil in hypersonic plasma turbulence increases gradually. By improving the aerodynamic shape of the aircraft, it can produce a large number of anisotropic turbulent eddies which can effectively improve the passive jamming capability when the foil is cast.