A Phase-Based Technique for Localization of UHF-RFID Tags Moving on a Conveyor Belt: Performance Analysis and Test-Case Measurements

Abstract

A new phase-based technique for localization and tracking of items moving along a conveyor belt and equipped with UHF-RFID (Ultra High Frequency -Radio Frequency IDentification) tags is here described and validated. The technique is based on a synthetic-array approach that takes advantage of the fact that the tagged items move along a conveyor belt whose speed and path are known a priori. In this framework, a joint use is done of synthetic-array radar principles, knowledge-based processing, and efficient exploitation of the reader-tag communication signal. The technique can be easily implemented in any conventional reader based on an I-Q receiver and it does not require any modification of the reader antenna configurations usually adopted in UHF-RFID portals. Numerical results are used to investigate the performance analysis of such method, also furnishing system design guidelines. Finally, the localization capability is also demonstrated through a measurement campaign in a real conveyor belt scenario, showing that a centimeter order accuracy in the tag position estimation can be achieved even in a rich multipath environment.

Order-of-Arrival of Tagged Objects

“…where ⇠ 1 , ⇠ 2 and ⇠ 3 are the local basis vectors for the curvilinear coordinate system. 3 The curvilinear system is defined such that the first vector ⇠ 1 changes direction point to point according to the conveyor direction. Based on this definition, the first coordinate of the curvilinear system determines the OOA of the N o tagged objects.…”

“…As an example, network localization and navigation is employed for handling goods in warehouses, in the automatic steering of items in supply chains, and in the routing of luggage in airports. The sorting and tracking of goods and things moving along a known trajectory, is an essential process for all the aforementioned applications and is referred to as order-ofarrival (OOA) tracking [1]- [3].…”

Chipless Radio Frequency Identification (RFID) Sensor for Angular Rotation Monitoring

“…Together with this employment based on the encoding of a univocal identification (ID) number in the electromagnetic footprint of the RFID tag, (which has reached a good point of maturity), an additional declination of the RFID technology is represented by the realization of sensors. Several directions have been explored in this sense, spanning from something as simple as measuring temperature [3,4] and gas [5,6], to more complex usage in healthcare [7,8], structural monitoring [9,10], localization [11][12][13], as well as food chain control [14,15]. However, although the presence of an integrated circuit (IC) in a RFID tag guarantees interesting features (in terms of large data storage and reprogrammable capability), it also poses some constraints on the item price and operating environmental conditions.…”

RSSI Measurements for RFID Tag Classification in Smart Storage Systems

“…N the context of the Internet-of-Thing paradigm, the UHF radio frequency identification (RFID) technology is gaining increasing attention for item-level tagging in smart spaces [1] such as smart cabinets/shelves and smart fitting rooms [2]- [5]. In addition to automatic real-time inventory, the UHF-RFID passive technology can be used to implement low-cost radiolocalization techniques for item localization in indoor scenarios [6]- [10]. In this context, a measurement system locating a tagged object in shelves/drawers allows developing additional capabilities, as, for example, to avoid misplaced items in pharmaceutical or retail environments [11] (e.g.…”