Error Reduction in Positioning in RFIDs for Use in Medical Instruments

Abstract

A positioning system for medical instruments using RFIDs or IC tags and a wireless LAN has been in operation in Mie University Hospital since January 2012. The tags are mainly attached to infusion pumps and some of them are equipped with a function to detect the ON/OFF status of each pump. Although it is possible with this system to acquire various data which could be utilized for proper management of the medical instruments, cost required for battery exchange in IC tags is unignorable. In this study, we investigate suppression of battery consumption of the IC tags by reducing the number of channels used during transmission. The reduction in the number of channels, however, could lead to increased positioning errors of the tags. In order to improve the position estimating accuracy degraded from reducing the number of transmission channels, Bayes’ theorem was applied to the estimation with the result that the positioning errors could be reduced to less than about 3 meters even when the number of channels was three.