Device-free localization (DFL) based on the received signal strength (RSS)measurements of radio frequency (RF)links is the method using RSS variation dueto the presence of the target to localize the target without attaching anydevice. The majority of DFL methods utilize the fact the link will experiencegreat attenuation when obstructed. Thus that localization accuracy depends onthe model which describes the relationship between RSS loss caused byobstruction and the position of the target. The existing models is too rough toexplain some phenomenon observed in the experiment measurements. In this paper,we propose a new model based on diffraction theory in which the target ismodeled as a cylinder instead of a point mass. The proposed model can willgreatly fits the experiment measurements and well explain the cases like linkcrossing and walking along the link line. Because the measurement model isnonlinear, particle filtering tracing is used to recursively give theapproximate Bayesian estimation of the position. The posterior Cramer-Rao lowerbound (PCRLB) of proposed tracking method is also derived. The results of fieldexperiments with 8 radio sensors and a monitored area of 3.5m 3.5m show thatthe tracking error of proposed model is improved by at least 36 percent in thesingle target case and 25 percent in the two targets case compared to othermodels.
展开▼
