说明：  基于RSSI的定位，已知发射节点的发射信号强度, 接收节点根据接收信号的强度, 计算出传播损耗, 利用理论的或经验的信号传播模型将传播损耗转化为距离, 然后再计算出节点的位置。
(RSSI-based positioning, known to the launch of the launch signal strength node, receiving node based on received signal strength to calculate the spread of wear and tear, or experience the use of the theory of signal propagation loss model will be spread into the distance, and then calculate the location of the node .)