Handling Positioning Errors in Location-based Services

Location–based services (LBS) shall typically only be provided within an authorized zone. This is enforced by location–based access control (LBAC) and affected by occurring positioning errors. Recent research has brought up different approaches for LBAC strategies. However, up to now it is unclear which strategy should be chosen for a given LBS and positioning system under realistic boundary conditions. In detail, the false authorization decision may cause severe additional costs when operating the underlying LBS. Hence, this paper presents a methodology to analyze the expected costs of LBAC strategies under the occurrence of positioning errors. The correlation to the practical costs occurring under realistic conditions is evaluated in an extensive case study. It is shown that in certain situations risk–based authorization is easily mislead by imprecise position error estimates and thus games away its theoretical superiority. In such situations, ignoring estimated errors may even yield lower expected costs of operating the LBS. The presented methodology contributes to finding the most suitable authorization strategy when deploying a LBS. This finally helps to reduce costs occurring from false authorization decisions when operating the LBS. Keywords—Location–based Access Control; Risk–aware Authorization; Positioning Errors