陀螺仪噪声对轨道高低不平顺检测的影响

Influence of Gyro Scope Noise on Track Longitudinal Irregularity Inspection

基于Allan方差和功率谱密度的关系,测定陀螺仪的角度随机游走、零偏不稳定性、角速率随机游走等分形噪声的功率谱密度;利用测定的分形噪声功率谱密度计算对应噪声的比例因子,并采用快速傅里叶变换仿真三种分形噪声的时间序列样本。用最小二乘法拟合仿真分形噪声得到对数斜率并与分形噪声的标准功率谱比对,验证了仿真分形噪声的真实性。推导基于陀螺仪的轨道高低不平顺检测算法,并以正弦波窄带信号模拟轨道不平顺,通过链式法则对时间和空间求导以获取高低不平顺对应的陀螺仪角速率。陀螺仪角速率叠加仿真分形噪声后,基于陀螺仪的轨道高低不平顺算法获得轨道不平顺,减去相同的算法流程处理未叠加噪声的陀螺仪角速率获得的轨道不平顺,二者差值可表征陀螺仪噪声对轨道高低不平顺检测的影响。

Based on the relationship between Allen variance and power spectral density,the power spectral density of fractal noise such as angular random walk,zero bias instability and angular rate random walk of gyroscope was measured. The scale factor of the corresponding noise was calculated by using the measured fractal noise power spectral density,and the time series samples of three kinds of fractal noise were simulated by FFT transform. The logarithmic slope of the simulated fractal noise was fitted by the least square method and compared with the standard power spectrum of the fractal noise to verify the authenticity of the simulated fractal noise. The detection algorithm of track longitudinal irregularity based on gyroscope was deduced,and the track irregularity was simulated by sine wave narrowband signal. The angular rate of the gyroscope corresponding to the longitudinal irregularity was obtained by deriving the time and space through the chain rule. After the gyroscope angular rate was superimposed with the simulated fractal noise,the track irregularity was obtained based on the track irregularity algorithm of the gyroscope,and the track irregularity obtained by subtracting the same algorithm process to deal with the gyroscope angular rate without superimposed noise. The difference between the two can characterize the influence of gyroscope noise on the track longitudinal irregularity inspection.