Subway train stop detection using magnetometer sensing data

The schedule of subway provides information on the arrival and departure of a train at stations. The subway passengers often refer to the subway schedule to make an appointment or to make their own schedule. Many apps on subway schedule are available for smartphone users. For example, in Korea, there are more than 10 apps that users can download to get the schedule of subway. However, most of the apps provide the schedule of subway based on fixed time table. As a result, there is no way to inform the differences between the time on the time table and the actual arrival time of a subway train. In this paper, we propose a method to provide correct information on the schedule of subway. Detecting the arrival of a train is required, and the difference between the time on time table and the actual arrival time of the train should be known. The method detects the arrival of a train based on the magnetometer sensing data. Then it identifies the arrived stop and computes the time differences between the schedule and the actual. The identified time differences are reflected to the time table to inform more correct schedule to the rest of the users. When we tested the detection accuracy of a subway train using the proposed technique at Seoul subway line, it showed over 90% accurate results. This indicates that the proposed method can be widely accepted to the subway schedule app developers.