卷帘快门sCMOS相机对空间碎片观测的影响研究

Study on the effect of rolling shutter sCMOS camera on space debris observation

同每个像素曝光开始及结束时间相同的传统科学级CCD相机相比,近年来出现的卷帘快门(rolling shutter)sCMOS相机工作时每个像素的曝光开始及结束时间不同,曝光时间相同,因此需要评估sCMOS相机像素之间曝光开始及结束时间不同对空间碎片测量精度的影响。首先测试了卷帘快门sCMOS相机的工作时序和最大延迟时间,并得出曝光不同步的改正公式,再以激光卫星为目标,测试了两种典型观测模式下空间碎片的天文定位精度,并对应用曝光不同步改正前后结果进行对比。测试结果表明sCMOS相机卷帘快门的工作时序与理论一致,边缘曝光延迟最大10ms;实测表明恒星位置内符合精度优于2arcsec,目标天文定位精度优于3arcsec。sCMOS相机能够用于空间碎片观测,能够实现较高的位置测量精度。

Compared to traditional scientific CCD cameras in which the exposure of each pixel starts and ends synchronously, rolling shutter sCMOS cameras have recently emerged and operate based on an asynchronous start and end time, but with the same exposure period. For space debris observation, it is necessary to evaluate the effect on the measurement accuracy due to the asynchronous exposure among the sCOMS pixels. Firstly, the working sequence and max delay of certain sCMOS cameras were tested, and a correction formula was obtained. Subsequently, several laser satellites were selected as observation targets to test the astronomic positioning accuracy of space debris under two typical observation modes. The differences before and after exposure with non-synchronization correction were then compared. The experimental results indicate that the working sequence of a rolling shutter sCMOS camera is consistent with a theoretical device, and the maximum delay in the border row is 10 ms. The results also indicate that the internal accord accuracy of the staller position is better than 2 arcsec, and better than 3 arcsec for the precision of object astronomic positioning. Rolling shutter sCMOS cameras can be used for space debris observation with high-precision position measurements.