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DeviationCalibratingforDigitalMagneticCompasswithoutHeadingReferenceZhangJingTianWeifengJinZhihuaDepartmentofInstrumentEngineeringShanghaiJiaoTongUniversityP.R.ChinaAbstract:Calibratingdeviationapproachescanbeextendedforadigitalmagneticcompasswhichcanobtaintri-axialmagneticfluxdensitiesandtiltanglesbesidesheadingoutput.Thispaperproposesthedeviationcalibrationstrategysuitableforimplementationonspotforanunmannedairshipwhichwillworkinsmalltiltangles.Basedonthedeviationcharacteristicsthispaperadoptsthreeapproachestocalibrateit.Thehardironstrengthiscoarselyestimatedbyrotatingthecarrierinacircle.Thustheremainingdeviationisconsideredassmallorder.Forhard-ironstrengthandsoft-ironcoefficientsleast-squareestimationatmulti-positiontestorrecursiveleastsquareandKalmanfilterforreal-timeestimationarerespectivelyapplied.ThecompensationresultsaretestedforHMR3300digitalmagneticcompass.Itshowsthatthecoarsecalibrationstepandaccuratecalibrationstepcanimprovetheheadingaccuracyundercarriermagneticdisturbance.1degreeheadingaccuracycanachievewhencarriertiltangleislessthan5degree.Thestrategyproposedinthispaperexpandsthepresentmethods.Itdoesnotneedaheadingreferencetoachieveaccurateestimationforhardir