Variable interval positioning method for smartphone-based power-saving geofencing

The objective of this research is to realize a method that detects a user's entrance to predefined geographic area so that appropriate services are provided without explicit user action. Though such geofencing technology is gathering attention due to its wide range of applications, it is a challenge to overcome trade-off between power consumption and detection accuracy. Conventional variable interval positioning methods fall short on battery saving due to difficulties such as sparse and erroneous position measurement data, and the unpredictable speed and trajectory of the terminal. In this paper, we propose a method for position detection whose activation frequency is determined by speed toward the target spot. The method is robust against positioning error and fluctuation of the terminal's movement by leveraging the access angle to the target spot. Simulation results show that the proposed access speed correction method reduces power consumption from 42% to 52% against conventional method, while holding the false negative ratio to detect the target spot to less than 5%.