关键词: 无线传感器网络, 到达时间差, 室内定位, 射频, 超声波

Abstract: Interferences and collisions among the signals of different beacons，to indoor location system with the decentralized architecture for wireless sensor networks，become the one of the important factors that decreases location accuracy.In this paper，an improved method to generate the random-delay-time is presented，and it can reduce the radio frequency collisions according to the relationship between beacon numbers and characteristic of radio frequency.In addition，serious interferences are decreased by using decreased-weight method at the same coverage of ultrasound from deferent neighbor beacons.To obtain the high location accuracy，an algorithm is also proposed to choice the proper distance information.

Key words: Wireless Sensor Network（WSN）, Time Difference of Arrival（TDOA）, indoor location, radio frequency, ultrasound