基于邻近点特征的地磁室内定位方法及性能分析

Geomagnetic Indoor Positioning Method and Performance Analysis Based on Proximity Points Feature

关键词:  地磁场  室内定位  定位误差  邻近点数  特征提取

Key words:  Geomagneticfield  Indoorpositioning  Positioningerror  Proximitypoints  Featureextraction

摘要:

地磁室内定位以其成本低、适用范围广、复杂度低的特点而受到广泛关注。然而,它的定 位精度不稳定,且指纹采集工作量较大。因此,提出了一种基于磁场信息的邻近点特征,可由指纹 数据求得,特征范围是0~1。经实验证明,邻近点特征与定位精度呈正相关关系。邻近点特征越 大的测试点定位误差越小,定位准确率越高。邻近点特征均值越大的室内区域定位误差越小。结 合邻近点特征与快速构建指纹库的方法,可以实现对室内区域定位精度的预判,为室内区域定位 方法的选择提供依据。针对邻近点特征较大的室内区域,提出了使用插值算法以减少指纹库的采 集量。在实验中,仅采集原有指纹点的29.6%依然具有较好的定位表现,对定位精度的影响较小。 使用邻近点特征可以极大地提高地磁室内定位的效率。

Abstract:

Geomagneticindoorpositioninghasbeenwidelyconcernedforitslowcost,widerangeof applicationandlowcomplexity. However,itspositioningaccuracyisnotstable,andthefingerprintcollectionworkloadisheavy. Inthispaper,afeaturebasedonmagneticfieldinformationof proximitypointcanbeobtainedfromfingerprintdata,andthefeaturerangeis0~1.Experiments showthatthecharacteristicsofadjacentpointsarepositivelycorrelatedwiththeaccuracyofpositioning. Thelargertheproximityfeature,thesmallerthepositioningerrorofthetestpoint,and thehighertheaccuracyofthepositioning.Thelargertheaverageofproximityfeature,thesmaller theindoorpositioningerror.Combiningthecharacteristicsofadjacentpointswiththemethodof quickconstructionoffingerprintdatabasecanrealizeprejudgmentofpositioningaccuracyoftheindoorarea, andprovideabasisfortheselectionoftheindoorpositioningmethod.Inviewoftheindoorareawithlargeproximityfeature, itisproposedtouseinterpolationalgorithmtoreducethe collectionoffingerprintdatabase.Inourexperiment,only29.6%oftheoriginalfingerprintpoints arecollected,whichhaslittleeffectonthepositioningerror.Theefficiencyofgeomagneticindoor positioningcanbegreatlyimprovedbyusingproximityfeatures.