The Study Of Acoustic Source Localization Technology Based On Wireless Sensor Network's Node

Wireless sensor network is a combination of sensor technology, embedded computing, network and wireless communication technology, which is a new technology of information acquisition and processing. The problem of target localization is precondition of wireless sensor network for target recognition, monitoring, tracking and many other applications, that is also an important supported technology of wireless sensor network technologies . It is made up of a large number of sensor nodes deployed in the monitored region, the nodes can complete the sensation,collection and processing of specific target attributes or events, and inform timely the user by measuring the heat, infrared, sonar, radar or vibration signals to access to temperature, light intensity, noise, pressure, motorial object size, speed and direction such attributes of the target and under a multi-node collaboration of the network.Wireless sensor networks taking on characteristic of high reliability,easy deployment and scalability etc., are gradually paid attention to, and has been developing rapidly.In the thesis, acoustic source localization was applied to wireless sensor network node. In terms of hardware, acoustic source localization systems of Y-shaped array was designed. The system adopted TI company's TMS320F2812 digital signal processor as the hard core.It can caculate cross-correlation and the angle calculation for the acoustic signals acquired by the acoustic arrays, and reached precise localization of the acoustic source signal in real-time. In terms of software, first of all, simulation about the cross-correlation time-delay estimation algorithm and array algorithm was implemented at the theoretical point, and its results showed the feasibility of the algorithms. Secondly, the compiler and optimization of the program code and algorithm was taken by the use of program code development environment (CCS) of DSP and completed the design of each functional module. Finally, power is the lifeblood of wireless sensor networks. Low-power modes of the system was also designed and implemented in the idle, standby and halt modes, as well as the wake-up modes of the three low-power modes. It was enable the system in sleep mode and reduced the power consumption to 25% compared in normal operation mode, and extended the working life of the nodes.By experimenting the acoustic signals of target,and the localization ambiguity of periodic signal was solved fundamentally to improve the localizatin accuracy.Tests results showed that the maximum accuracy of system is about 4.0122°,and completed accurate localization of acoustic source.