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

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 launch the node transmission signal strength, the receiving node according to received signal strength, transmission loss calcula

For free space path loss, fc=1.5GHz (Carrier frequency) If we take different antenna gains such as 1.(Gt=1,Gr=1)and 2.(Gt=1,Gr=0.5)and 3.(Gt=0.5,Gr=0.5) When we reduce the antenna gains (i.e. the transmitting gain or the receiving gain) there is

衰落是由于发射机与接收机之间空间位置的微小变化引起的，描述小范围内接收信号场强中瞬时值的快速变化特性，是由多径传播和多普勒频移两者共同作用的结果，包括由多径效应引起的衰落和信道时变性引起的衰落，具有信号的多径时延扩展特性和信道的时变特性-Fading is caused due to a slight change of the position of the space between the transmitter and the receiver, the characteristics

本系统为立体声调频收音机，设计采用RDA5807收音模块，与单片机相结合，使收音解调电路设计变的简单，实现FM收音并显示频率。我们通过矩阵键盘设定我们需要的频段，并设置音量大小，通过诺基亚5110液晶屏显示出来，并根据所显示接收信号的强度等级，判断收音所在地的信号强度。RDA5807模块具有65-108MHz全球FM接收频段相容的效果，具备噪声消除、软静音、低音增强、灵敏度高、噪声小、抗干扰能力强等功能，所以使用本模块很容易实现，且系统可靠稳定。-This system is design