BLE测距精度影响因素评估分析

Evaluation and analysis on influencing factors of BLE ranging accuracy

针对低功耗蓝牙(BLE)测距精度不稳定且误差较大的问题,提出一种BLE测距精度影响因素评估分析方法:选取BLE信距转换模型、信号传输角度、BLE协议版本和遮蔽环境等4种影响因素进行实测实验,分析全域函数模型、分段函数模型、终端和BLE信标相对角度大小、4.2和5.0不同协议版本、人体/易拉宝/纸板/穿孔铁板遮蔽环境等与BLE测距精度的关系。结果表明,基于分段拟合函数的BLE信距转换模型能小幅度提高拟合精度;信号传输角度越大等价距离圆上信号接收强度(RSS)值越小;同距离下不同BLE协议版本的RSS不相等;人体遮挡等遮蔽环境破坏BLE信号衰减规律而导致RSS降低。

Aiming at the problem of unstable bluetooth low energy(BLE)ranging and large error,the paper proposed an evaluation and analysis method on influencing factors of BLE ranging accuracy:four influencing factors,such as BLE signal-distance conversion model,signal transmission angle,BLE protocol version and masking environment,were selected to conduct field experiments;and then the relationship between the facorts including global function model,segmented function model,the relative angle size of terminal and BLE beacon,different protocol versions of 4.2 and 5.0,the shielding environment formed by human body/roll screen/cardboard/perforated iron plate,and BLE ranging accuracy was analyzed.Results showed that the BLE signal-distance conversion model based on piecewise fitting function could improve the fitting accuracy to a certain extent,and the larger the signal transmission angle,the smaller the received signal strength(RSS)value on the equivalent distance circle;moreover,the RSS of different BLE protocol versions under the same distance would be unequal,and the masking environment such as human body shielding would destroy the attenuation law of BLE signals,resulting in the reduction of RSS.