山区航道虚拟航标基站布设间距研究

Base station spacing of virtual aids to navigation in mountain waterways

针对山区航道中布设虚拟航标基站缺乏指导方法的问题,从基站AIS信号覆盖的角度推导基站布设间距模型。首先,通过实地实验采集山区航道AIS信号场强,发现Egli模型总体上高估了山区航道中AIS信号衰减的速度,山体遮挡会造成AIS信号场强快速下降。然后,基于实验数据,采用曲线拟合误差的方法修正Egli模型的参数,得到适合于山区航道的AIS信号场强评估的修订模型。修订模型对AIS信号场强的评估精度提高到94%以上,较Egli模型提高了55%以上。最后,基于修订模型,以-107 d B·m作为基站信号覆盖范围边界,推导山区航道的虚拟航标基站布设间距模型。该模型能保证船舶接收到基站信号的可靠性高于80%。

To address the problem of the lack of guidelines for deploying virtual aids to navigation（ Ato N） base stations in mountain waterways,this research proposes a spacing model for base stations from the perspective of field strength estimations of the automatic identification system（ AIS） signal. First,we conducted a field experiment to capture the field strength of the AIS signal. The experimental results show that the Egli model overestimated the attenuation of the AIS signal in mountain waterways,and the palisades severely decreased the field strength of the AIS signal. With the experimental data,we were able to revise the parameters of the Egli model through curve-fitting. Consequently,we achieved a modified Egli model,which can better estimate the field strength of the AIS signal in mountain waterways. Our results show that this modified Egli model increased the accuracy of the estimated field strength of the AIS signal to more than 94%,which is over 55% higher than that of the original Egli model.Finally,taking-107 d B·m as the transmittal boundary condition of the base station＇s AIS signal,we derived a virtual Ato N spacing model for base stations in mountain waterways from the modified Egli model. This spacing model can ensure a signal reception rate higher than 80%.