Research On Self-localization For Acoustic Sensor Array Network

Acoustic sensor array network, the basic idea of which is to combine the acoustic sensor array technology and wireless sensor network technology, is a new high-performance integrated model of information processing. Awareness of the physical location and orientation of each acoustic sensor array node is required for data fusion and network management. How to achieve self-localization efficiently in a lower cost is a meaningful work.Based on the locating techniques of wireless sensor network and the feature of acoustic sensor array network, two self-localization mechanisms are presented for acoustic sensor array network, one is based on mobile beacon and DOA (Direction of Arrival), the other one is based on target sound source and DOA. Simulation analysis and experimental validation are also presented for proposed mechanisms.Self-localization mechanism based on mobile beacon and DOA contains three main algorithms:BML (Basic Maximum Likelihood estimator), PCML (Propagation Compensated Maximum Likelihood estimator) and RML, (Recalculation Maximum Likelihood estimator). Mobile beacon can significantly improve the reuse of beacon nodes, effectively reduce the required equipment or labor costs. In particular, the impact of propagation delay is studied and regarding this PCML and RML have made the compensation. Key factors such as the speed of the beacon, DOA error and sensing range of the node, which affect node self-localization accuracy and computational complexity and other implications, are well analyzed.Self-localization mechanism based on target sound source and DOA first gets target's location or trajectory using the least squares estimator or extended Kalman filtering. Then unknown nodes can locate themselves through BML, PCML, or RML assuming targets as the beacon (i.e., pseudo-beacons). This self-localization mechanism is mainly for the following questions:1, due to the limited number of fixed beacon nodes, undesirable mobile strategy of mobile beacon or undesirable process of laying, etc, some of the nodes especially the nodes in edge of the network are not able to achieve effective self-localization; 2, due to physical impact or other factors during the working process, the location or orientation of some nodes have changed, and a re-self-localization is needed.In addition to the analysis in theory and simulation on proposed mechanisms, a real system, which combined the latest achievements of acoustic array technology and wireless sensor network technology, was set up and analysis through experimental data was also given to validate their feasibility and effectiveness.