目前的轨道谱分析是基于用等间隔采样数据描述轨道不平顺特征，而机车实际运行速度的变化必然导致采样的非均匀性，传统的谱分析方法必然产生原理误差。为提高非均匀采样信号分析的准确性，研究了平稳随机过程非均匀采样序列，导出了非均匀采样信号的功率谱表达式，应用该表达式分析了采样间隔服从正态分布的非均匀采样情况，证明了非均匀采样信号功率谱表达式包含了均匀采样这种特例，涵盖了经典理论，验证了新公式的正确性，并提出了进行轨道谱分析时用于求取功率谱表达式中所含有的采样间隔的概率密度函数等统计特征量的方法。

Current spectral analysis for track irregularity is based on sampling data at a uniform interval, but the train is of fluctuation velocity, therefore the accuracy of routine spectral analysis is in doubt. A nonuniform sampling sequence was studied to set up the power spectral density(PSD) formula of nonuniform sampling signal. The new formula was applied to analysis the nonuniform sampling cases when the sampling interval is of the Gaussian distribution probability density function. The result shows that the PSD formula of nonuniform sampling signal includes the classic uniform sampling signal’s PSD formula, which verifies the accuracy of the new formula. Finally a method was put forward to measure the probability density function of the sampling interval for the track irregularity spectral analysis.