Development of a Zigbee-Based Indoor Positioning System for Asset Tracking in a Nigerian Teaching Hospital

High-value medical equipment is frequently misplaced or stolen in large Nigerian teaching hospitals, resulting in treatment delays and financial losses. This project developed a Zigbee-based indoor positioning system for real-time asset tracking within a teaching hospital in Osun State, South West Nigeria. Eight Zigbee coordinator and router nodes (XBee Series 2) were mounted on the ceilings of four floors of a 60-bed ward block. Tracked assets were tagged with Zigbee end-device nodes, each transmitting received signal strength indication values to all router nodes within range every 10 seconds. A Python localisation server running a weighted centroid algorithm processed multi-node RSSI values to estimate asset position on a 2D floor plan with 1-metre grid resolution. Estimated positions were displayed on a hospital asset map accessible via a local intranet web page. The system was tested by tracking 10 tagged wheelchairs across a 4-floor ward block over 5 hours. Mean positioning error was 2.8 metres across all floor locations, with accuracy improving to 1.6 metres in areas covered by 4 or more router nodes. Asset map update interval was 12 seconds. Battery life of end-device nodes was 18 days on two AAA alkaline batteries. The study recommends upgrading the localisation algorithm to a particle filter approach for improved accuracy in multipath-rich hospital corridor environments and conducting a cost-benefit analysis of the system against a commercial RTLS solution for the hospital's administration.

Keywords: indoor positioning, Zigbee, asset tracking, teaching hospital, Osun State