"Sugar-Cube" PLT: A Real-time Pedestrian Localization Testbed Utilizing Foot-mounted IMU/Barometer/Ultrasonic Sensors

In this paper, we propose a flexible multi-sensor hardware platform, "Sugar-Cube" Pedestrian Localization Testbed (PLT), for pedestrian navigation in GPS-challenged environments. The Sugar-Cube platform is the next generation of the Lab-On-Shoe platform [1] and aims to provide a flexible and easy-to-use development environment with a compact form factor. The proposed platform includes a micro-controller to collect measurements from a consumer-grade 9-axis Inertial Measurement Unit (IMU), a barometer, and an ultrasonic sensor and performs localization of a user in real-time. All source codes, hardware designs, and documentation related to the Sugar-Cube PLT will be available at [2]. We conducted a series of indoor walking experiments to verify the navigation accuracy of the Sugar-Cube platform and compared the navigation results with the Lab-On-Shoe system, which was equipped with near-tactical-grade IMUs. The experimental results showed that the Sugar-Cube platform could localize its user in real-time with a horizontal position Circular Error Probable (CEP) of 0.76 m and a vertical displacement Root-Mean-Square-Error (RMSE) of 0.24 after navigating for 60 s on mixed terrains, including flat planes, ramps, and stairs.