【摘要】 对于卫星导航系统，定位误差受对流层大气折射率影响，提高对流层大气折射率预测的精确性能够降低导航定位误差.对流层大气折射率是研究对流层对电磁波传播影响的主要参数，其预测的精确性对于无线电系统有重要意义.本文提出一种基于反向传播(back propagation,BP)的对流层折射率预测方法，将年、月、日、时刻、地表折射率、海拔高度作为网络模型的输入，输入海拔高度处的折射率作为模型的输出；类似地，通过调整输入和输出参数，还可以利用BP神经网络预测近地面1 km折射率梯度.在此基础上，利用香港地区和太原地区历史探空气象数据对新提出算法进行了计算分析，并与现有文献中的方法作了比较，结果表明：本文提出的方法在计算的精确性方面有一定的优势.更多还原

【Abstract】 Research on methods to improve the timing accuracy and timekeeping capability of timing signals under satellite timing. By using a crystal oscillator counter, the crystal frequency information at the moment of each second pulse is recorded; the recorded historical information is input into an extended Kalman filter(EKF) for filtering, to eliminate the random error of the satellite second pulse signal, and extract the accumulated time of the first frequency by the EKF is used as the training set, input into the long short-term memory(LSTM) network to establish a prediction model; the algorithm parameters are debugged using the control variable method to find the most suitable prediction model. The experimental results show that the maximum error of the timing signal output by the timing algorithm is 34 ns; the cumulative error of the timing algorithm in 8 hours is 1.001 μs, and the average error is less than 0.125 μs/h. This effectively improves the timing and timekeeping accuracy of the system.更多还原