In the typical urban environment, GPS standalone can hardly satisfy the requirement of continuous positioning, particularly in the weak signal or no signal environment. Fortunately, this problem can be solved by using the integration method based on GPS and non-LOS (Line of Sight) positioning such as RFID positioning. To solve the problem of computational load in the traditional GPS/RFID integration based on all selection of RFID observations, this research proposed an optimal selection method of RFID observations with the minimum positioning error under the wcighted observation condition. The experiment results show that the geometric distribution of precision in the environments, such as shadow or blockage, can be improved by using the proposed method, and both availability and accuracy of positioning can be improved efficiently. Moreover, the computational load can be decreased dramatically through this proposed method.%在典型的城市环境中,单一GPS定位模式已很难满足连续定位的要求,采用GPS和其他非LOS(Line of Sight,视线矢量)定位方法(如RFID定位方法)进行组合可实现弱信号或无导航信号环境下的定位.针对GPS/RFID组合定位系统中全选RFID观测值所带来的较高的计算复杂度的问题,提出了一种在加权观测值条件下使组合定位误差最小的RFID观测值优选方法.实测实验结果表明,采用这种优选RFID观测值的GPS/RFID组合定位系统可改善在GPS信号受遮挡条件下的GDOP值,有效提高单一卫星导航定位系统的定位可用性和定位精度,并大大降低了系统的计算复杂度.
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