Research And Implementation Of Node Localization In Wireless Mobile Sensor Networks

With the rapid development of sensor technology, micro-electronics technology, wireless communication technology, integrated circuit technology and computer technology, low power consumption, low-cost, miniaturized wireless sensor network technology came into being. In the military and industrial applications of wireless sensor networks, in order to achieve the purpose of collecting environmental infor-mation accurately and efficiently, it is necessary for node with mobility. The concept of the wireless mobile sensor networks has emerged; meanwhile, the mobile node lo-calization has also become one of the key issues that cannot be avoided by research-ers.At present, domestic and foreign scholars have proposed many node localization algorithms. Most of these algorithms are based on the RSSI method, mainly measur-ing the distance of the node and the reference node by computing the received signal intensity of the node, so as to achieve the purpose of the unknown node positioning. In some special applications of wireless sensor networks, GPS and ultrasonic methods of positioning can also be adopted. This paper proposed a new node localization scheme, called multi-sensor scheme. This scheme is based on the inertial navigation systems. We improved the positioning method in the inertial navigation systems and integrated it into the wireless sensor networks.The proposed multi-sensor positioning scheme, include the displacement calcu-lation method and displacement calibration method. The displacement is calculated by the triaxial acceleration sensor and the orientation sensor. In the process of movement, the triaxial acceleration sensor obtains the acceleration of the node movement and the orientation sensor obtains the node posture instantaneously. After the acceleration data and the direction angles of the node are obtained, the displacement of the node’s movement can be calculated through the corresponding integral calculation. After the completion of the displacement calculation, we use the displacement self-calibration method and auxiliary calibration method to calibrate the displacement. In this paper, we use the line acceleration values when the calibration method, linear acceleration values smaller calibration method, the line acceleration values change when calibra-tion method, the direction attitude changes when the calibration method. When the line acceleration value and direction of the gesture value changed greatly at the same time, we adopt a variety of calibration methods to reduce the measurement error. Meanwhile, we used the extended Kalman filter to eliminate the error caused by the zero drift in order to improve the accuracy of the entire displacement calculation.Finally, the scheme was tested on a cell phone equipped with a three-axis accel-eration sensor and a direction sensor. Plenty of testing data indicate that this mul-ti-sensor solution fitted to test the small displacement. It has a larger accuracy in the small range test. As a self-localization multi-sensor solution, supplemented with the existing auxiliary locating methods, it can improve the efficiency and accuracy of the node localization significantly.