Liu Ran, Yuen Chau
Highly relevant in Singapore’s densely populated urban setting, the Indoor Relative Positioning System localizes the positions of mobile users in an indoor environment. In addition to ambient sensors in the environment, such as WiFi and FM, the system utilizes inertial measurement unit sensors on the users to estimate their positions. Peer-to-peer information is also used to correct the users’ paths. For example, the Bluetooth device carried by user A is able to detect other users nearby, helping user A locate his peers effortlessly. Logistics and factories are just two of the areas where this useful innovation can be applied.
You can find more details at https://www.sutd.edu.sg/Research/Research-News/2014/3/Indoor-Relative-Positioning-System