椭圆拟合方法在磁罗盘罗差校准中的应用  

Application of ellipse fitting method to calibration of magnetic compass deviation

作　　者：孙宏伟[1] 房建成[1] 李艳[2] 

机构地区：[1]北京航空航天大学仪器科学与光电工程学院新型惯性仪表与导航系统技术国防重点学科实验室,北京100191 [2]中国人民解放军总参谋部第55研究所,北京100190

出　　处：《光学精密工程》2009年第12期3034-3039,共6页Optics and Precision Engineering

基　　金：国防基础科研重大项目(No.D2120060013);国家自然科学基金重点资助项目(No.60736025)

摘　　要：磁罗盘在使用过程中受周围铁磁物质的影响致使航向精度降低,因此对磁罗盘进行校准是十分必要的。针对传统的磁罗盘罗差校准算法存在系数矩阵易奇异导致算法不稳定的问题,提出了改进的最小二乘椭圆拟合算法。分析了外界磁干扰对磁罗盘输出的影响,建立了罗差的椭圆模型,通过对系数矩阵的奇异性进行分析,采用最小二乘方法实现了对椭圆模型误差系数的辨识。该算法克服了原有算法的不稳定性,对校准过程中的突变干扰有很强的抑制能力,同时将六维特征矢量的求解转化为三维特征矢量求解,在保证校准精度的情况下降低了计算量。多位置转台实验验证了该方法的有效性和实用性,校准后的磁罗盘精度由0.8°提高到0.4°,满足了导航系统的需求。It is essential to calibrate the compass deviation for a magnetic compass , for the navigation precision of the magnetic compass can be affected by the ferromagnetic materials in working environments. A improved least square ellipse fitting method was presented in this paper to improve the sta bility of the traditional calibration method that the coefficient matrix may be singular. The effect of the magnetic interference on the output of magnetic compass was analyzed and a ellipse model for the compass deviation was established. By analysis on the singularity of a coefficient matrix, the error coefficients of the ellipse model were identified by the least square ellipse fitting method. Experimental results show that the method suppresses the instability and prevents from the pulse disturbance. Moreover, by transforming six dimensional eigenvector＇s solutions into three dimensional eigenvector＇s solutions, it can reduce the computation load while keeping the precision. The multi-position experimental results prove the validity and practicality of this method and show that the precision of the calibrated magnetic compass is improved from 0. 8° to 0. 4°, which meets the requirement of the navigation system.

关 键 词：磁罗盘 罗差 校准 最小二乘法 椭圆拟合 奇异性 

分 类 号：V249.32[航空宇航科学与技术—飞行器设计]