无航向基准时数字式磁罗盘的自差校正ahref=11a.pdf

无航向基准时数字式磁罗盘的自差校正1

张静田蔚风金志华
(上海交通大学仪器工程系，上海，200030)

摘要：数字式磁罗盘除输出载体的磁航向之外，还能测量载体的水平姿态角和三个正交方向的磁通密度值，
这为磁罗盘自差的校正提供了更多的技术途径。针对某无人驾驶飞艇中安装罗盘吊舱的工作状态，本文提出
适合于野外作业环境无外部航向基准时数字磁罗盘的自差校正方法。通过分析自差产生的原因以及硬铁和软
铁磁力对自差的不同影响，采取了粗校和精校两步走的策略。先用磁力畸变特性进行硬铁校正，再把自差当
作小量，分别采用最小二乘法、递推最小二乘法和卡尔曼滤波器进行剩余硬铁磁力和软铁系数的估计。通过
HMR3300数字磁罗盘的自差校正实验表明，该方法能提高磁罗盘在干扰磁力下的测量精度，在载体倾斜<5°
条件下，航向角测量精度由原来的6°提高到1°。这种方法无需航向基准实现自差校正，扩展了现有的磁罗盘
校正方法，适宜于工程应用。
关键词：磁罗盘，自差，最小二乘法，卡尔曼滤波，校正

DeviationCalibratingforDigitalMagneticCompasswithoutHeadingReference
ZhangJing,TianWeifeng,JinZhihua
DepartmentofInstrumentEngineering,ShanghaiJiaoTongUniversity,P.R.China
Abstract:Calibratingdeviationapproachescanbeextendedforadigitalmagneticcompass,whichcanobtain
tri-axialmagneticfluxdensitiesandtiltanglesbesidesheadingoutput.Thispaperproposesthedeviationcalibration
strategysuitableforimplementationonspotforanunmannedairship,whichwillworkinsmalltiltangles.Basedon
thedeviationcharacteristics,thispaperadoptsthreeapproachestocalibrateit.Thehardironstrengthiscoarsely
estimatedbyrotatingthecarrierinacircle.Thustheremainingdeviationisconsideredassmallorder.Forhard-iron
strengthandsoft-ironcoefficients,least-squareestimationatmulti-positiontestorrecursiveleastsquareandKalman
filterforreal-timeestimationarerespectivelyapplied.ThecompensationresultsaretestedforHMR3300digital
magneticcompass.Itshowsthatthecoarsecalibrationstepandaccuratecalibrationstepcanimprovetheheading
accuracyundercarriermagneticdisturbance.1degreeheadingaccuracycanachievewhencarriertiltangleisless
than5degree.
Thestrategyproposedinthispaperexpandsthepresentmethods.Itdoesnotneedaheadingreferencetoachieve
accurateestimationforhardironstrengthandsoftironcoefficients,sothattheheadingdistortioniscalibrated.The
dataprocessusingrecursiveleastsquareestimationandKalmanfilterisintendedforon-linecircumstances.
Keywords:magneticcompass,magneticdeviation,least-squareestimation,Kalmanfilter,self-calibration

0引言
随着MEMS技术的发展，微小型磁罗盘相继问世，它将两个倾斜仪和三个磁阻传感器集成在一起，并带
有模数转换和微处理器，可在一定倾斜范围内输出航向信息，其