基于复合信标的农田节点定位研究

Research on Farmland Node Localization based on Complex Beacon

及时准确的采集农田信息是精准农业的关键,节点定位问题也因此成为农田无线传感网络应用的核心问题,为解决此问题,这里提出了固定信标与移动信标的复合信标节点定位方法。使用装有GPS或其他定位系统的移动装置,作为移动信标节点,同时在传感监控区域内加入不同数量的固定信标节点。该复合信标节点定位方法有效的提高了节点定位精度,同时提高了节点覆盖率。采用加权最小二乘法与扩展卡尔曼滤波相结合的算法,通过仿真结果分析了随着信标数的增多,平均定位误差明显减小;同时通过增大初始状态误差斜方差阵,可以很好抑制增大的初始误差对EKF滤波精度的影响。

Timely and correct acquisition of field information is the key to implementing precision agriculture, and node localization thus becomes the core of farmland WSN （wireless sensor network） application. A complex beacon node localization in combination of fixed beacons and mobile beacons is proposed in this paper. By using mobile devices with GPS or other positioning system as mobile beacon node while adding different numbers of fixed beacon nodes to the sensing network, this localization algorithm could raise the coverage rate of network node and positioning accuracy effectively. Simulation indicates that this algorithm, in combination of weighted least squares estimation with EKF （Extended-Kalman Filter） could significantly reduce the average location error with the increasing of beacon numbers. Meanwile, the effect of the increasing initial error on accuracy of EKF filter could be efficiently constrained with the expansion of error oblique variance matrix.