A BLE based turnkey indoor positioning system for mobility assessment in aging-in-place settings

Indoor positioning systems (IPS) can be used to measure mobility at home, which is an important indicator for health and wellbeing. In this work, we designed and developed a Bluetooth Low Energy (BLE) based IPS that identifies individual users; does not require floorplans; and allows the end-users to perform on-site install/setup. Additionally, a dynamic calibration process is implemented to learn room boundaries based on the distribution of the BLE signal strength. The functionality and performance of IPS system were validated in two residential home settings. Raw and filtered relative signal strength indicators (RSSI) and variability of RSSI were measured during testing. Room detection was determined by comparing a user input location (ground truth) with the IPS detected location for over 300 positions. The IPS produced a 96% accuracy of correctly detecting room location when using RSSI and the additional motion sensors. The use of PIR motion and ultrasonic sensors information provided improved validity when compared with existing indoor positioning systems. The ease of use and modular design of this IPS makes it a good choice for implementation in larger scale smart healthcare monitoring systems.Author summary: Mobility is a critical indicator of health status, particularly for older adults with co-morbidities. Accurate, quantitative, and long-term measurements of in-home mobility provide valuable data to the healthcare team for diagnosis and interventions. Existing methods to measure mobility at home have poor compliances and/or are difficult to scale up to large number of users living in community dwellings. In this project, we designed and developed a smart indoor-positioning-system (IPS) technology that allows accurate measurements of in-home mobility, while remains low cost to implement and operate. The turn-key design of the IPS technology can be installed, set up, and calibrated by the end users (e.g., older adults and/or their caregivers) themselves. The system itself is low cost, and its operation requires minimal interactions with the old adult end users. These features significantly alleviated the burdens to the end users, which are key barriers to compliance and effectiveness of such technologies, making it feasible to scale up to large number of users in the community.