An Efficient Method for Hyperbolic-Based Localization in SAR RFID Systems

Radio frequency identification (RFID) is one of the major wireless communication technologies and has been applied in the supply chain and retail network for a long time. By contrast, the application of RFID in localization emerges in recent years. Besides, neither precision nor real time of existing RFID localization methods is satisfactory enough. In this article, we propose a novel method called HyLoc for localization of RFID tags based on the hyperbolic model. The problem to locate RFID tags is modeled as the solution of hyperbolic equations formed by synthetic aperture radar (SAR). To solve the equations quickly, the linear least-squares (LLS) algorithm is first used to find the approximate solution, and then, the estimation error is corrected by the Taylor series method for higher accuracy. Comparisons of performance with the state-of-the-art methods in SAR RFID localization are carried out through simulations and experiments. The results show that the proposed method is closer to the Cram & x00E9;r & x2013;Rao lower bound than the holography method at high noise level and more efficient than the ordinary nonlinear least-squares (NLS) method without loss of accuracy.