Localization of position using radio frequency identification array

Abstract

In distribution centres, usability of an automated guided vehicle depends on the accuracy of its positioning system. In manufacturing industries and global supply chains, one of the biggest operational costs is to manage movement of goods and materials within the distribution centres. This type of goods movement involves numerous trips. A wide variety of technologies have been proposed but there are still issues in terms of cost, accuracy, line of sight, and installation. To overcome these issues, the inclusion of radio frequency identification (RFID) transponders as a location data source has been found to be promising. The advantage of an RFID system is that it can read a large number of transponders without simultaneous line of sight of the transponders. This paper describes a low-cost, highly flexible two-dimensional positioning system using an RFID array. A large number of experiments are performed and the position of an object is computed by the weighted average method. The effectiveness of different weighting functions to find an optimum strategy for calculating the localized positions over the area of the array is evaluated. Preliminary experimentation shows that this system is capable of locating an object within the array to an accuracy of 31 mm, with an average accuracy of 67 mm, using an array with a 350 mm spacing between tags.