直升机平台振动对太赫兹SAR成像的影响分析

Effects analysis of helicopter platform vibration on terahertz SAR imaging

太赫兹合成孔径雷达(SAR)能够克服传统机载SAR成像帧率低,慢动目标检测困难等问题。然而相比传统微波波段的SAR,由于载波的波长极短,太赫兹SAR对平台高频振动误差更为敏感。对于适合应用太赫兹SAR系统的直升机平台而言,其振动也明显强于传统的固定翼载机平台,平台振动引起的相位误差将严重影响成像效果。为克服平台振动对太赫兹SAR的影响,采用数值仿真方法,结合直升机平台的振动特性,较为全面地仿真分析了振动谱宽、振动幅度、谐振分量等因素对太赫兹SAR成像质量的影响,得出了平台振动参数与成像系统参数之间的约束条件。

The terahertz Synthetic Aperture Radar(SAR)can tackle with the problems of the low imaging frame rate and poor ability of detecting slow targets for the traditional airborne SAR.However,compared with the traditional SAR in microwave band,the terahertz SAR is more sensitive to the high frequency vibration error of the platform because of the very short carrier wavelength.Meanwhile,the vibration of helicopter platform which is suitable for the terahertz SAR is more violent than that of the traditional fixed wing aircraft platform.Thus,the phase error caused by the platform vibration has a serious effect on the imaging quality.To eliminate the effects of platform vibration on terahertz SAR,the numerical method is adopted to comprehensively analyze the effects of vibration spectrum width,vibration amplitude and resonance components on the imaging quality of terahertz SAR,combining the vibration characteristics of helicopter platform.The constraint conditions between the vibration parameters of platform and the parameters of imaging system are obtained.