Interrogator Choice Methods for Improvement of Localization Estimation in LOS Indoor Environments

Abstract

RTLS(Real Time Location System) is a tracking technology for devices, assets and people and the accuracy of position is a critical issue in RTLS. In this paper, we propose two kinds of interrogator choice schemes, that is, random interrogator selection and combined interrogator selection methods to enhance the locating accuracy over indoor wireless LOS (line-of-sight) channels. The performances are compared with those of the conventional methods called as normal and reference interrogator choice schemes. These interrogator choice schemes are based on received signal strength(RSS) levels and trilateration method. A testbed is set up to measure and compare the positioning estimation error of the proposed methods and previous conventional ones. The experiments results shows that the accuracy of location estimation is enormously improved with the combined method as much as 3m especially in a hostile environment with some obstacles. Meanwhile, the differences of estimation errors are not so much as less than 0.2m without obstacles among the four kinds of interrogator selection methods.