APS: An Auditable Positioning System Based on Angle-of-Arrival Proof of Location and Graph of Trust

With the fast growth of the Internet ofThings, location-based services are becoming more important for quality-relevantapplications. Quality-relevant applications often require to be auditable inorder to ensure quality of products and services. However, positioning systemstypically only provide position claims that are not secured and can be forgedor manipulated. This work proposes an auditable positioning system to tacklethis issue. The proposed system performs a proof of location to assert that thetracked asset tag was at the claimed position and immutably stores thisinformation on a distributed ledger. Additionally, an adaptive storage rate wasproposed to save disk storage on the distributed ledgers. A testbed based onBluetooth's Angle of Arrival positioning was implemented for the evaluation ofthe auditable positioning system. The evaluation shows that auditablepositioning is secure, feasible for low-power devices, and that adaptivestorage rates can significantly reduce disk usage and improve scalability.