模拟和数字加速度仪记录的一个主要问题是参考基线的失真和飘移。在地震作用下的土－结构相互作用分析时，直接由地面加速度记录积分得到的位移通常存在基线飘移。在大跨度结构相互作用分析中，这种飘移会对分析结果带来严重的影响。本文提出了一个简单的方法来移除长周期噪声进行基线调整。首先在时域内对加速度进行最小二乘拟合处理，接着通过EMD提取趋势项来进一步去除积分位移中的长周期影响。通过数值模拟信号和实测记录对比验证了此方法的可靠性。

A major problem encountered with both analog and digital accelerograms are distortions and shifts of the reference baseline. Accumulating experience indicates that direct integration of the ground acceleration data provided for seismic soil-structure interaction analysis often causes unrealistic drifts in the derived displacement. The drifts may have a significant effect on large-scale interaction analysis in which the displacement excitation is required as an input. The paper proposes a simple approach to remove long-period noise to acquire a realistic displacement-time series. In this approach, the acceleration data is firstly baseline-corrected in the time domain using the least-square curve fitting technique, and then using empirical mode decomposition (EMD) to extract signal trend to remove effect produced by long-period signal. Both simulated and field measured signal are employed in this study to demonstrate the feasibility of this approach.