Self-Localization Systems And Algorithms For Wireless Sensor Networks

Study and development of Wireless Sensor Networks (WSN), have been proposed for a multitude of diverse applications. One of the most important applications is monitoring the environment which is dangerous and hardship for human. It has much meaning in the military and civilian fields.Self-localization technology is one of the most important technologies of Wireless Sensor Networks. In this thesis, self-localization systems and algorithms in existence of WSN are introduced and analyzed. Then a new kind of range free self-localization algorithm is developed based on DV-Hop algorithm. And a self-localization algorithm is promoted in 3D space.Communication radius of sensor nodes can be adjusted by hardware design. Under the premise of ensuring network connectivity, the smallest radius of communication is used to reduce communication energy. When maximum radius is used, most nodes of the monitoring space can have"handshake"with the beacon node. And this radius is recorded. Count the number of beacon node's neighbor nodes. If the number is too big, narrowing the communication radius gradually, until the number is proper. Sensor nodes transmit beacon node information, and then compute the distances between sensor nodes with formula. Finally coordinates of unknown sensor nodes are computed. In the algorithm there are two methods to compute distances between beacon nodes and unknown nodes. One is beacon node communication radius, and the other is using hop distances to compute. Compare tow results, error can be control in a certain range.100 sensor nodes are used in the computer simulation by software. Compare simulation results, which are got in different coverage and density beacon nodes, to get the best localization conditions. In this condition, accuracy of this algorithm is higher than DV-Hop algorithm. It can meet application needs.