title: HyBloc: Localization in Sensor Networks with Adverse Anchor Placement.
abstract: To determine the geographical positions of sensors, numerous localization algorithms have been proposed in recent years. The positions of sensors are inferred from the connectivity between sensors and a set of nodes called anchors which know their precise locations. We investigate the effect of adverse placement and density of anchors on the accuracies of different algorithms. We develop an algorithm called HyBrid Localization (HyBloc) to provide reliable localization service with a limited number of clustered anchors. HyBloc is distributed in nature with reasonable message overhead. Through simulations, we demonstrate that HyBloc provides more accurate location estimates than some existing distributed algorithms when there are only a few anchors. HyBloc also performs well when anchors are clustered together.
authors.affiliation: Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong; E-Mails:  kycheng@eee.hku.hk  (K-Y. C);  vtam@eee.hku.hk  (V. T.).
authors.forename: King-Yip
authors.initials: KY
authors.lastname: Cheng
authors.forename: King-Shan
authors.initials: KS
authors.lastname: Lui
authors.forename: Vincent
authors.initials: V
authors.lastname: Tam