天线形变对风云卫星遥感图像的影响

Effect of Antenna Deformation on Remote Sensing Images of FY Satellites

为探究反射面天线形变对风云卫星毫米波和亚毫米波成像仪(MMSI)的亮温图像质量的影响,运用基于表面电流积分的物理光学方法计算天线辐射方向图,探究不同形式反射面天线形变下天线辐射特性的变化规律。结合MMSI的亮温图像的处理结果,评价图像质量的变化。实验结果表明:反射面天线的形变面积、形变位置和副反射面晃动发生变化时,天线的主瓣增益、副瓣电平和波束宽度等关键指标发生规律性变化,对MMSI的亮温图像质量产生不同形式的影响。当反射面天线的形变面积增大时,天线的主瓣增益减小,副瓣电平升高,进一步导致分辨率降低,噪声水平升高,亮温图像质量变差。

In order to explore the effects of the deformation of the reflector antenna on the brightness temperature image quality of millimeter and sub-millimeter sounding/imager(MMSI)carried by FY satellites,physical optics(PO)method based on surface current integral is used to calculate the antenna radiation pattern and then the variations of the antenna radiation characteristics are analyzed under different forms of deformation of the reflector antenna.Combining with MMSI's bright temperature image processing,we evaluate the changes in image quality.The experimental results show that when the deformation area,deformation position and sub-reflection surface sloshing of the reflector antenna change,the key indicators such as main lobe gain,side-lobe level and beam width of the antenna change regularly,and then the brightness temperature images of the MMSI are affected by different forms.The antenna gain decreases and the side-lobe level increases when the deformation area increases,then the resolution decreases,the noise level increases and the brightness temperature deteriorates.