在无源信号的定位过程中,由于现实环境的复杂性和易变性,直接使用接收信号强度指示(RSSI)定位会受到环境中障碍物的干扰,导致整个系统中的已知参考节点接收到存在误差的定位参数信息,造成定位失准.为了滤除干扰因素、提高定位精度,提出了一种针对无源信号RSSI定位的最大似然估计(MLE)优化算法.该算法在参考节点接收信号强度与传输距离模型的基础上,求取无源信号在实际环境中传播时,接收信号强度RSSI的累计概率分布函数,并利用概率模型对未知节点进行位置坐标估计.与传统三边定位算法的仿真比较结果表明,该算法稳定性更高,并有效减小了定位误差.%In the positioning process of the passive signal,due to the complexity and variability of the real environment,directly using received signal strength indication ( RSSI) positioning,the process may be disturbed by obstacles in the environment,and causes the known reference nodes in the entire system to receive the reference positioning parameter information with errors, resulting in locating misalignment. In order to filter out the interference factors and improve the positioning accuracy,a maximum likelihood estimation ( MLE ) optimization algorithm for RSSI passive signal positioning is proposed. Based on the model of received signal strength and transmission distance of reference nodes, through getting the cumulative probability distribution function of the RSSI when the passive signal is transmitted in the actual environment,then the position coordinates of unknown nodes are estimated by using probabilistic model. The simulation comparison between the proposed algorithm and the traditional trilateration algorithm shows that this algorithm has higher stability,and it can effectively reduce the positioning error.
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