【摘要】 针对无线传感器网络的特点,提出了基于测量经伪随机码相移键控调制的声波信号在无线传感器网络的节点之间往返传播时间的测距方法.发起测距过程的主动节点向目标节点发送调制声波信号,目标节点收到调制声波信号后,根据声波信号所携带的数字信息重建该信号,并回传给主动节点.主动节点测量发出的声波信号和从目标节点返回声波信号之间的时延,同时考虑到对调制声信号进行重建造成的信号延迟,从而估算出节点之间的距离.参与测距的节点之间不需要进行时间同步,也不需要预先知道对方使用的伪随机序列.利用声波信号携带的伪随机码序列确定声波信号时延的范围,然后再从确定的范围内求出声波信号的时延,从而极大地减小了算法的运算量.更多还原

【Abstract】 According to the characteristics of wireless sensor networks,a novel ranging method was proposed based on measuring propagation time of acoustic signal modulated with pseudo-random number through binary phase shift keying(BPSK)and flying to and for between two sensor nodes in a wireless sensor network.A node,which launches a ranging process and is called an active node,sends modulated acoustic signal to another node,called a taget node,which demodulates the acoustic signal received from the active node,gets the pseudo-random number sequence carried by the acoustic signal,regenerates the received acoustic signal with the pseudo-random number sequence,and then sends it back to the active node.The active node measures the time delay between the acoustic signal it sent and the acoustic signal it received from the target node and then,taking into account the extra time delay caused by signal demodulation and modulation executed on the target node,estimates the distance between the two nodes.Precise time synchronization is not needed.The target node does not need to know in advance the pseudo-random number sequence sent by the active node.The active node,using cross-correlation function and the pseudo-random number sequences carried by the acoustic signals,determines the scope of general time delay first and then computes the precise value of the time delay in this scope.So the computational complexity or workload of the algorithm of this ranging method is much smaller than usual to compute the entire cross correlation function values.更多还原