dv-hop的定位算法，已知网络中几个锚节点就可以计算出网络中其他点的坐标，但这种算法有时由于网络密度的稀疏，可能误差会有一些-dv-hop positioning algorithm, known to the network a few anchor nodes on the network can calculate the coordinates of other points, but this algorithm is sometimes due to the sparse network density may be some errors