紫外临边成像光谱仪时间同步系统的优化

为了提高紫外临边成像光谱仪的系统在轨时间同步精度，提出了采用参考时钟源计算时钟漂移率的方法。对光谱仪的时间系统工作原理进行了分析，利用光谱仪系统中的1553 B 接口芯片的时标单元作为参考时钟源，获得连续的样本数据，确定了线性拟合计算时钟漂移率，实现对时钟漂移进行动态补偿和光谱仪时间系统优化。给出了基于GPS 时钟源的实时检测方法，采用高速FPGA 芯片设计了时间同步系统；应用仿真测试设备，记录光谱仪时间同步误差的动态变化，实现了动态测量优化后的光谱仪时间同步误差的目的。实验结果表明:优化后的系统实际测量开始时间误差13 ms，不同测量持续时间下的测量结束误差466.8 ms，不同积分时间下的测量结束误差362.5 ms，满足光谱仪数据反演精度时间系统误差512 ms 的要求。

Optimization design of time synchronization system in ultraviolet limb imaging spectrometer

To improve the time synchronization precision of ultraviolet limb imaging spectrometer, the algorithm of clock drift rate calculation which was based on reference clock source was put forward. Firstly, the principle of limb time system was analyzed, then by using time tag unit of 1553B interface chip as clock reference source, the continual sample data was obtained and clock drift rate based on linear fit was calculated. Lastly, dynamic compensation of clock drift rate and optimization of limb system were realized. With using GPS time synchronization system, time synchronization system of high speed FPGA chip was designed, therefore dynamic changes of limb time synchronization errors were recorded by simulation and test equipment, furthermore limb time synchronization errors were measured dynamically. Time synchronization precision was measured. Experimental results indicate that time synchronization errors are no more than 13 ms for imaging beginning time error, the imaging finish time errors no more than 466.8 ms in different imaging time and no more than 362.5 ms in different integration time, which meets the demand of no more than 512 ms of qualification.