机载成像光谱仪CCD制冷系统设计与实现

为减小紫外成像光谱仪中CCD暗电流噪声,提高系统信噪比,需要对CCD进行制冷.为此采用模拟比例-积分-微分电路设计了CCD制冷电路,利用Zregler-Nicholas经验整定方法确定比例-积分-微分参量,以实现降温速率不大于5℃/min、温度稳定度为±0.05℃,满足最大制冷温差.将该制冷系统应用于机载成像光谱仪进行了测试,结果表明:环境温度变化不会影响制冷效果,在达到制冷目标温度-20℃后,CCD探测器暗背景下光谱维噪声平均灰度响应值为1 072,暗背景信号非均匀性下降到0.5%,满足光谱数据反演要求.

The Design and Implementation of CCD Refrigeration System of Imaging Spectrometer

To decrease CCD dark current noise and improve the signal to noise ratio in airborne ultraviolet imaging spectrograph,CCD working temperature should be decreased as CCD is temperature sensitive device.So CCD cooling circuit was designed by adoping analog PID algorithm,and its parameters were determined by Ziegler-Nicholas method.The max cooling rate is less than 5 ℃/min and its temperature stability is about ± 0.05℃,satisfing the requirements of maximum cooling temperature difference.The cooling circuit has been tested on airborne system.The experimental results show that change of temeperature could not affect the cooling results.And after reaching the target refrigeration temperature of-20 ℃,dark background noise of spectral dimension CCD detector is 1 702 on average and dark signal response non-uniform decreases to 0.5 ％.The results meet the requirements of spectral data.