Optimizing Spectral Waveband Selection for Spectral Radiation Detection of Hypersonic Vehicle

Space-based spectral radiation detection is one of the most effective approaches for detecting hypersonic vehicles. However, due to complex characteristics of the plasma sheath that is generated by aerodynamic thermal effect and envelopes hypersonic vehicle, space-based spectral radiation detection is still confronted with great challenges. Based on the mechanisms of spectral radiation and transmission, we establish a model to conduct optimal selection on spectral wavebands for detecting hypersonic vehicle. Through using the established model, we obtain the spectral radiation characteristics of plasma-sheath-enveloped vehicles (RAM-CII and HTV2) under different flight conditions (at 40-70-km altitude with 10-25-Mach velocity). The optimal spectral wavebands for space-based detection are analyzed and identified using the calculated spectral data, upon which the results reveal that significant differences exist in spectral radiation intensities of different flight status for those two vehicles. The overall radiation intensity of RAM-CII vehicle is higher than that of HTV2 vehicle, to which the optimized detection wavebands corresponding to velocity and altitude differ. Generally, at different altitudes, the optimal wavebands for both vehicles are 5.00-7.86, 2.59-3.44, and 1.81-2.10 \mu \text{m} . At different flight speeds, the optimal bands are 0.78-1.13 \mu \text{m} and 99-130 nm, respectively. Combined with the optimized speed and height bands, the optimal detection bands of RAM-CII vehicle and HTV2 vehicle are 5.00-7.86 \mu \text{m} , 2.59-3.44 \mu \text{m} , and 99-130 nm. The above findings can provide useful data for in-depth study of space-based spectral radiation detection.