市区环境下北斗B1信号双通道联合跟踪环路设计

Compass B1 signal Double-channel union tracking loop design in urban area application

  • 摘要: 北斗导航系统已正式公开其B1频点,为亚太大部分地区提供导航,授时,定位服务。在城市环境实现导航定位是其一项重点应用。但是,城市内遍布高楼,桥梁,树木等遮挡物,对卫星信号产生衰减,遮挡,使接收机接收到的卫星信号强度低于-150dBm,甚至达到-160dBm,远远小于设计的-130dBm。另外,城市道路中,大部分情况下接收机是运动的,所以遮挡与衰减不是固定的,而是动态变化的。所以如何在该种信号状况下完成跟踪,以及如何在信号短暂消失后快速恢复信号,是北斗导航系统在城市环境中应用的研究重点。本文,根据实际道路应用特点以及北斗导航手持单天线接收机信号跟踪特性,设计了一种使用两个通道跟踪一颗卫星的方法,对信号能量下降情况,两个通道分别采用环路保持和弱信号跟踪两种处理方式,完成在信号强度低于-160dBm的环境下的信号跟踪。并通过实际道路测试,证明该方法在定位可用性上有较大提升。

     

    Abstract: The B1 signal of Compass has opened its service to Asia-Pacific region which provide the service of navigation, timing and location. One of the main applications of Compass is to navigate in urban area. However, as there are a lot of huge Building, large overpass and trees which will blank and weaken the signal to -150dBm, or even to -160dBm, far less than the designed -130dBm, the receivers cannot receive the signal formally. Furthermore, the block and attenuation change in real time, it is difficult for receiver to work well in urban area. In the paper, a novel one satellite double-channel tracking method is designed according to the real urban situation and the single antenna handhold receiver property. When the power of the signal begins to decrease, the two channels will process the signal with loop keeping method and special designed weak signal tracking method respectively. After real urban test, it is proved that the new method will help the location to be more available.

     

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