小型化光纤陀螺的轴向磁场误差特性建模方法探讨

Investigation on modeling methods of axial magnetic field error characteristics in small fiber optic gyroscope

小型化光纤陀螺的主要特点是光纤环径向尺寸逐步缩小,而轴向尺寸逐步增大,由此导致轴向磁场误差成为影响小型化光纤陀螺精度的重要因素之一。以小型化光纤陀螺轴向磁场误差特性为研究对象,依据光纤环中光纤的四极对称排列结构,提出轴向螺旋角展开分析法,利用Jones矩阵分别构建保偏型光纤陀螺及消偏型光纤陀螺的传输矩阵及轴向磁场误差模型,探讨光纤扭曲应力寄生圆双折射、轴向尺寸等因素与非互易性Faraday磁场相位误差的关系,得出光纤陀螺轴向磁场漂移误差的数学描述,以此为理论依据,探讨小型化光纤陀螺的轴向磁场误差因素,并提出相应的措施。

A significant feature of small interferometric fiber optic gyroscope is that the fiber ring radial size is becoming smaller,and the axial dimension is becoming larger.As a consequence,the axial magnetic field error becomes one of the important factors that affects the gyroscope precision.By studing the Faraday phase error of axial direction magnetic field in small interferometric fiber optic gyroscope,the coil helical angle expansion method is proposed based on fiber loop＇s quadrupolar winding distribution structure.Then,the transmission matrix and magnetic phase error models of interferometric depolarized fiber optic gyroscope and interferometric polarization maintaining fiber optic gyroscope in axial direction are respectively established by using Jones matrix.Based on these models,the relations between Faraday magnetic field non-reciprocal phase error and residual circular birefringence coming from twist of fiber in fiber loop,axial dimension are studied.Then the axial phase drift in interferometric depolarized fiber optic gyroscope and polarized interferometric polarization maintaining fiber optic gyroscope are deduced and described mathematically.Based on the theoretical models,the factors of axial magnetic field error in small fiber optic gyroscope are discussed,and the measures to deal with them are proposed.