基于阈值机制与距离校正的WSN改进DV-Hop定位算法

在无线传感器网络的DV-Hop定位算法中，未知节点定位只考虑离它最近的锚节点的平均跳距，用它乘以跳数代替真实距离去进行定位，会导致较大的定位误差。针对DV-Hop算法以上的不足，本文提出了一种精度较高的基于阈值机制与距离校正的DV-Hop改进算法TMCD-DV-Hop。改进算法首先计算跳数阈值，考虑最近锚节点之外的其他锚节点在局部范围和全局范围的影响，依据阈值选择最优的校正平均跳距来估计距离，并对参与定位的单跳通信半径内的锚节点进行组合优化后，采用质心算法得到一个估计坐标，同时利用加权最小二乘法得到另一个估计坐标，最后以两个估计坐标的算术平均值作为未知节点的定位坐标。仿真实验表明，在同等网络环境中，改进后的TMCD-DV-Hop算法较DV-Hop算法更能有效地降低定位误差，提高定位精度。

An Improved DV-Hop Localization Algorithm Based on Threshold mechanism and Correcting distance for Wireless Sensor Networks

In the wireless sensor network DV-Hop localization algorithm,the location of unknown nodes only consid?ers the average hop distance from its nearest anchor node,which is used to multiply the number of hops to replace the real distance but thus,it will lead to large positioning errors. This paper proposes a high-accuracy localization al?gorithm TMCD-DV-Hop,which is a developed DV-Hop algorithm of relative high accuracy,based upon threshold mechanism and distance correction and the developed algorithm firstly calculates hop thresholds,and the effect of the other beacon nodes lying outside the nearest anchor node in the local range and global range is considered ,thus, best corrected average hop distance has been chosen to estimate the distance,and an estimated coordinate is gained by centroid algorithm after the combinatorial optimization of anchor nodes within the single-hop communicative radi?us,meanwhile,another estimated coordinate is gained by weighted least-squares method. At last arithmetic mean of two estimated coordinates is considered as orientation coordinate for unknown nodes. Simulation experiment mani?fests that in the same network environment,developed TMCD-DV-Hop algorithm could better lower down position?ing errors than DV-Hop in the end the positioning accuracy is elevated.