基于6 类噪声项拟合模型的光纤陀螺噪声特性分析方法

针对传统的陀螺噪声特性分析方法出现拟合模型不准确的问题,提出一种基于6 类噪声项的拟合模型及分段拟合方法。采样某型光纤陀螺数据,分析了导致拟合模型不准确的内在机理,指出在光纤陀螺随机噪声中存在低频正弦项噪声成分,该项噪声在传统的5 类噪声拟合模型中通常被忽略。对于精度较高的光纤陀螺,这种忽略处理导致其拟合模型不合理、拟合系数结果不准确。通过对实测陀螺信号进行时域、频域分析,确定正弦项噪声的频率,将正弦项噪声纳入拟合模型中,提出一种包含6 类噪声项的拟合模型,同时为减小正弦项噪声、量化噪声项、零偏不稳定项、速率斜坡项等因相关时间相近而带来的耦合误差,提出一种分段拟合方法。针对某型光纤陀螺的实测数据的Allan 方差,基于6 类噪声项的拟合模型,采用文中所提方法进行噪声特性分析。结果表明:六类噪声项的拟合模型的拟合误差很小,拟合系数准确、可信。

Analysis Method for the Noise Characteristics of Fiber Optic Gyroscope Based on Fitting Model of Six Noise Items

A kind of fitting model and piecewise fitting method based on six kind of noise is proposed to solve the problem that the fitting model will probably be inaccurate by the traditional analysis method for the noise characteristics of fiber optic gyroscope. The reason of leading to the inaccuracy of fitting model is analyzed according to the data of a fiber gyroscope. It is found that a low frequency sinusoidal noise exists in the random noise of fiber-optic gyroscope. Compared with other gyroscope noises, this noise is small so that it was ignored in the traditional fitting model for five noise items, which may lead to the irrationality of fitting model and the inaccuracy of fit coefficients for optical fiber gyroscope,especially high precision optical fiber gyroscope. A fitting model for six noise items, including sine noise, is established by analyzing the time and frequency domains of measured gyroscope signal to determine the frequency of sinusoidal signal. A subsection fitting method is proposed to reduce the fitting error coupled by the approximating correlation time of sinusoidal noise, quantization noise, zero offset instability and rate ramp. The measured data of fiber optic gyroscope is analyzed with Allan variance based on the fitting model for six noise items. The results show that the fit error of the fitting model is small, and the fit error coefficient is accurate and credible.