Aiming at application scene of wireless sensor networks（ WSNs） in 3D space

based on centroid algorithm

put forward 3D positioning algorithm for WSNs

based on centroid of intersection region projection of anchor ball（ BCIP-3D）. This algorithm can determine possible space coordinates by working out centroid of mass which by anchor sphere intersection be projected to XOY plane and YOZ plane. The algorithm transforms the positioning problem from 3D space positioning solution to 2D positioning and reduces amount of calculation

and projection of anchor ball in plane is cycle which with the same center and radius as the anchor sphere. As a result

by working out the centroid of projection area

high precision space coordinate of unknown node can be obtained. The theoretical analysis and simulation experimental result both show that the algorithm has the characters of small amount of calculation

high precision of positioning and good stability.