Research And Application Of Localization Algorithm Based On RSSI In Wireless Sensor Network

Integrated modern sensor, micro-electronics, wireless communication, embedded computing, distributed information processing and other technologies, wireless sensor network (WSN) is an emerging research direction. Compared with the traditional networks, WSN is a data-centric wireless network with self-organizing and self-regulating characteristics, and can be widely used in military, agriculture, traffic, construction, emergent rescue and many other kinds of applications. Location information of each sensor node is essential to WSN. It is not only the basic of taking further measures and making decision-making, but also the research foundation of other key technologies (for example target tracking, routing supporting and network management) in WSN.Most of typical localization algorithms based on RSSI only have theoretical research, and the simulation environment needs idealized setting. They can't apply in actual environment or the actual test results are significantly different with the simulation results. Facing on the limitations of typical localization, lightweight localization technology research is carried out from four aspects in this thesis: environment attenuation factor model, person localization model, anchor selection strategy and angle weighted function. The important research results are as follows:①A weighted trilateration localization algorithm based on anchor node selection strategy and angle weighted function is put forward. The algorithm uses anchor node selection strategy to choose appropriate anchors, integrates multiple localization results based on angle weight to get high precision. It achieves higher localization accuracy and enjoys advantage on hardware.②A lightweight localization algorithm based on space compensated model and environment degradation factor model is put forward. The space compensated model is designed in order to minimize the localization error arosed by that the target node (the patrol soldier) and anchor node are in different planes. The existing RSSI-based localization technology which always uses wireless signal propagation theory model makes great error. By a large number of experimental data, the paper constructs the environment degradation factor model which decreases the error greatly.③Considering military patrol application environments, a lightweight localization application prototype system - multi-modal regional situation awareness prototype system based on WSN is built. Integrated weighted trilateration localization algorithm, compensated model and environment degradation factor model, a new localization strategy is put forward. The strategy is implemented on hardware platform (CC2430) and software platform (WSN stack). System performance tests full proof that the localization strategy has low hardware requirement and good localization accuracy. Also, the system can collect environmental information, monitor user's physiological information and interact with monitor center through multi-mode (voice, images and text).