中文摘要：

时间同步是传统测距的前提条件，也直接影响测距的精度．为消除测距对时间同步的前提限制和扩大测距的应用范围，提出了时间同步与节点测距混合算法．该算法结合了基于到达时间差的测距机制和网络时间协议中的时钟同步机制，通过逆推时间非同步情况下相互测距的意义，不仅能实现时间同步，还可以实现相对测距甚至绝对测距．理论分析和仿真实验表明该算法较RBS和TPSN在鲁棒性、同步精度和消息交换量方面有较好的效果．

英文摘要：

Time synchronization and distance measurement are the infrastructure for any distributed system including wireless sensor networks. Time synchronization methods rely on some sort of message exchange between nodes, the same to distance estimation. Although many researchers have investigated time synchronization or distance measurement, but little work has Been published on the relationship between them. Time synchronization is a prerequisite for conventional distance measurement and directly affects the accuracy of distance measurement in wireless sensor networks. In order to eliminate the restriction of time synchronization for distance measurement and expand the scope of distance measurement application, the authors present a coordinated algorithm for time synchronization and distance measurement （CATSDM） by backward analyzing the meaning of asynchronous paired ranging, which can realize not only time synchronization but also relative ranging and even absolute ranging. It combines time difference of arrival＇s ranging mechanism and network time protocol＇s synchronization principle. The task of TDOA is to correct time skew. The task of NTP is to correct time offset. Theoretical analysis and simulation results show it outperforms in terms of robustness, accuracy and the number of message exchange than TPSN （timing-syn protocol for sensor network） and RBS （reference broadcast synchronization）.