柱面非均匀弱磁场对光纤陀螺磁敏感性的影响

Effect on FOG Bias Error of Cylinder Nonuniform Distribute Weak Magnetic Field

摘要:

以光纤陀螺(FOG)某电路板为例,扫描分析了其磁场分布规律,并利用矩阵光学和光传输理论,建立了柱面非均匀磁场中Faraday非互易相位差理论模型,进而仿真分析了实际电路板的辐射磁场对光纤陀螺的影响。分析结果表明:1)柱面非均匀磁场与光纤环距离越小,FOG磁敏感相位误差越大;2)柱面非均匀磁场对FOG所产生的磁敏感误差与角度之间呈倾斜正弦曲线,且倾斜度随磁场与光纤环间距减小而加剧;3)当R<5r(磁场源位于光纤环外部,r为光纤环半径,R为磁场源与光纤环左侧边缘的距离)或R<0.5r(磁场源位于光纤环内部)时,非均匀磁场均大于同量级均匀磁场对FOG的影响;4)非均匀场的存在影响FOG偏离固有磁轴方向;5)对于距离FOG较近的一些辐射强度非常小的普通电路板,也会导致FOG输出的不稳定和方向相关性。上述结果对于理解和分析实际磁场对FOG的影响,具有实际指导意义。

Abstract:

Taking an optical fiber gyroscope(FOG) circuit board as the example, its magnetic field distribution was analyzed. And by using matrix optics and optical propagation theory, a theoretical model for Faraday nonreciprocal phase error was established in cylinder nonuniform magnetic field. The effects of radiation magnetic field on FOG were analyzed. Results indicate that, the nearer of the distance between the center of magnetic field and the fiber loop, the bigger of the bias error of FOG will be; the relationship between bias and magnetic field direction is a inclined sine, which becomes more gradient when the distance between the center of magnetic field and the fiber loop is nearer; the bias error caused by the nonuniform magnetic field is bigger than that caused by uniform magnetic field of equal intensity, when R＜5r (center of nonuniform magnetic field in fiber loop) or R＜0.5r(center of nonuniform magnetic field out of fiber loop); the existence of nonuniform magnetic field will affect the direction of magnetic axis; and the common circuit board with very weak radiate intensity will also cause unstable output of FOG and directional relativity.