Quantitative threshold analysis and mitigation of multi-scale parasitic modulation via inverse physical modeling

During hypersonic reentry, the plasma sheath induces complex parasitic modulation on electromagnetic signals, characterized by the strong coupling between amplitude attenuation and phase shift. Based on the established multi-scale nonstationary channel model, which decomposes plasma dynamics into large-scale trajectory trends, meso-scale angle-of-attack oscillations, and small-scale turbulence, this paper conducts a systematic quantitative threshold analysis for each scale. For small-scale turbulence, we identify a scattering threshold, where the phase jitter exceeds the Quadrature Phase Shift Keying (QPSK) tolerance, leading to an error floor. For meso-scale dynamics, we reveal a tracking failure threshold related to the receiver’s phase-locked loop bandwidth. For large-scale attenuation, the energy threshold leading to radio blackout is verified. Based on the deterministic nature of the derived channel model, we propose a signal reconstruction scheme based on inverse physical modeling. By computationally decoupling the amplitude attenuation and phase rotation, the distorted signal state is restored. The restoration of signal orthogonality serves as validation for the proposed multi-scale coupling mechanism.