Abstract: Positioning of distributed wireless sensor nodes is an important and fundamental problem in a wide range of applications, such as search and rescue, target tracking, supply chain management, disaster relief and smart environmenu. By deployed in physical environments, the nodes are envisioned to form ad hoc communication networks and provide sensed data without special communications infrastructure. In constrction project, equiped with RFIDs, the locations of materials and components become of immediate use if such construction resources arc to be tracked. hracking the locanon of construction resources enables effortless progress monitoring and supports real-time construction state sensing. hhis greatly improve the productivity and reduce the cost for the construction enterprise. For above reason, we gave a node positioning model in 3 dimensional space and specially discussed it's localization error. This model had successfully used in construction projrect management

Key words: Wireless sensor network, Cells, Reader, Tag, 3-dimensional positioning