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Localization systems are becoming an important feature for many RFID-based inventory and warehouse management support tools, due to the ever increasing diffusion of Radio Frequency IDentification (RFID) in logistic processes. RFID-based Location system will allow offering value-added services to logistics operators, where RFID tags can be used for more than just labeling items. This paper proposes a Received Signal Strength (RSS) based positioning system for perishable products equipped with active UHF RFID tags, inside a refrigerated warehouse (4C°). A fundamental problem in the design of RFID based localization system is the evaluation and mapping of the signal attenuation, which depends upon several parameters (fading from obstacles in the transmission path, reflections off surfaces and relative antenna orientation). Such information should be considered in the design phase, where instead simplified theoretical approaches are frequently employed. Theoretical path loss models are however inadequate for a reliable prediction of the signal strength, which significantly affects the accuracy of distance measurement and ultimately the precision of localization. An accurate prediction of the coverage level is hence required for obtaining a reliable design. In this paper, a case study on the design of an RFID localization system is presented, comparing a realistic signal distribution, obtained considering the influence of reflections and refractions, and the theoretical approach based on simple path loss models. Realistic coverage maps are obtained by means of a simulation tool based on 2D ray tracing algorithm. [ABSTRACT FROM AUTHOR]

In the industrial warehouse design domain, today’s computerized information systems have gained a relevant interest due to the issues related to asset tracking and traceability. In such context, the employment of new information technologies on warehouse management systems has opened new business opportunities due to the sensible price reduction in the last years. This paper focuses on the technical issues related to the realization of wireless localization systems for warehouses, which are necessary for the implementation of random allocation policies, and in particular investigates the opportunities offered by RFID technology in such context. The enforcement of random allocation policies allows to increase the utilization coefficient of warehouses which is a critical issue, for example in refrigerated warehouses for perishable products. In particular, the development of localization systems based on trilateration is here considered, and an experimental model which links the received signal strength to the reading distance has been determined in order to take into account the specific features of the technology employed. A~methodology is hence proposed to overcome the simplifying assumptions theoretical attenuation models rely on, by fitting a mathematical model on experimental observations. The problem of the accuracy level required to locate Stock Keeping Units (SKUs) of fixed dimensions is also considered, resulting in the evaluation of the maximum allowed reading distance. On the basis of the obtained results, the optimal configuration of the fixed infrastructure in terms of the number of antennas and their position is finally defined. [ABSTRACT FROM AUTHOR]