Aiming at general positioning mode provided by Zig Bee networks is just a passive way of monitoring

design a passive and active ways of bi-directional positioning system. The system hardware structure and compile method for bi-directional positioning Zig Bee protocol stack are given; through building Zig Bee network

moving node and coordinator can acquire the RSSI for positioning at the same time

and use fingerprint database based on path loss model and the three kinds of limited area localization algorithm for positioning calculation respectively.Experimental results show that this system can realize bi-directional positioning mode such as active positioning and passive positioning at the same time

and positioning precision can reach within 2 m.