Indoor Positioning System based on Bluetooth Low Energy for Blind or Visually Impaired Users : Running on a smartphone

Abstract: Blind and visually impaired (BVI) users desire an indoor navigation tool that is inexpensive, convenient, and reliable. The purpose of this thesis is to examine the feasibility of using a smartphone as a platform for such a navigation tool. A good navigation tool should have both a good positioning accuracy and a user-friendly interface. Thus, one focus of this thesis is to improve the performance of an indoor positioning systems running on smartphones, as compared to existing systems. Another focus is to customize this indoor positioning system specifically for BVI users.  The proposed indoor positioning system is based upon Bluetooth Low Energy (BLE). It consists of two parts: BLE beacons deployed in the user’s environment and an Android phone which calculates its position and provides navigation assistance by audio and vibration. Two versions of the positioning software were developed based on different algorithms. One version uses a hybrid technique combining triangulation and fingerprinting. This version achieves a positioning accuracy of 1.83 meter, and volunteers (blind-folded sighted people) took on average 91.7 seconds to complete a complex 12-meter route. The other version uses a proximity algorithm, thus it does not give as accurate positioning results. With this algorithm, a blind user was able to finish a route of 115 meters consisting of two different floors in a building including entering/exiting an elevator and multiple office doors in 4 minutes 48 seconds. The blind user found the product to be helpful and user-friendly. Finally, we draw the conclusion that a smartphone can be a good platform for a BVI navigation tool, under the condition that the algorithm is proximity based and navigation utilizes a priori information about the environment. Another insight we gained is that we should put beacons on braille signs so that blind people can find them by using the navigation app.