太阳光谱辐照度仪波长扫描设计

Design of wavelength scanning for solar spectral irradiance instrument

针对当前气候变化对太阳光谱辐射的观测需求,为精确监测太阳光谱辐照度,研制了波长扫描型太阳光谱辐照度仪。该太阳光谱辐照度仪主要由光谱测量单元和波长扫描单元组成,其中波长扫描单元作为色散光谱的精密定位机构,是保障仪器测量精度的关键。为此,设计了基于小型交流伺服电机的波长精密扫描定位装置,采用定时器主从方式控制电机旋转,并利用STM32驱动线阵CCD工作,结合CCD检测的光斑质心位置与预设位置的偏差进行闭环控制,闭环控制精度小于2个像元宽度。最后,对线阵CCD的质心位置检测的重复性以及扫描定位装置的稳定性进行测试,测试结果表明CCD质心位置检测的标准差为0.0693,最大偏差不超过0.3像元宽度,系统运行时闭环精度小于2个像元宽度,满足波长扫描的重复性和稳定性要求。

To meet the current demand of climate change for solar spectral radiation observation,a wavelength scanning solar spectral irradiance meter is developed in order to accurately monitor the solar spectral irradiance.The solar spectrum irradiance meter is mainly composed of a spectrum measurement unit and a wavelength scanning unit.As the precise positioning mechanism of dispersion spectrum,the wavelength scanning unit is the key to ensure the measurement accuracy of the instrument.Therefore,a wavelength precision scanning positioning device based on a small AC servo motor is designed.In the device,the rotation of the motor is controlled by a timer,the linear CCD is driven by STM32 to work,then the closed-loop control is realized with the precision less than 2 pixels based on the deviation between the centroid position detected by the CCD and the preset position.Finally,the repeatability of the linear CCD centroid position detection and the stability of the scanning positioning device are tested.It is shown that the standard deviation of CCD centroid position detection is 0.0693,the maximum deviation does not exceed 0.3 pixels width,and the closed-loop accuracy of the system is less than 2 pixels width during operation,which meets the repeatability and stability requirements of wavelength scanning.