Research on Tagless indoor person localization system

In the Internet of Things (IoT), the requirements for person localization and monitoring are getting higher and higher. The accuracy of the positioning is increasingly important as Location Based Service (LBS) are developing more and more quickly. Indoor person localization technologies have attracted widespread attention. Nowadays, more and more technologies are used in indoor person localization system. Earlier techniques required people to wear devices that sent signals, such as infrared light or ultrasonic waves, to allow the system to localize the human body through cooperative processing of receiver devices installed in the monitored space. However, these techniques have many limitations, such as the cost of the wearable devices for monitoring many persons, and in some cases, or discomfort or other problems related to wearing a device (e.g., forgetting, interference with specific activities, or psychological effects of a constant reminder of being monitored). Therefore, it is particularly important to design tagless indoor person localization systems. They are usually composed of one or more sensors installed in different locations in the monitored space as needed, and they do not require the person to wear any specific equipment or to explicitly interact with the monitoring system. They detect certain biological characteristics of the human body or specific life signs, such as temperature, weight (pressure), electrical capacitance, effects on the propagation of ultrasonic or electromagnetic waves, infrared radiation, etc. to achieve recognition, localization, tracking, and can also achieve the inference of activity using specific processing of the sensor data. The most commonly used sensing techniques are infrared sensing, ultrasound sensing, Wi-Fi based sensing, radar sensing, sensing based on ZigBee radio, ultra-wide band radio sensing, sensing using visible light processing, capacitive sensing, and pressure sensing. In this work is researched the state-of-the-art of the techniques and the results for tagless indoor person localization systems in the past 15 years. Are analyzed first the development of tagless indoor person localization systems from the technical principles, algorithms, solutions of challenges, experimental design schematics and results. Then are introduced the typical sensing techniques, processing techniques, and compared the techniques using several performance metrics: accuracy, privacy, power consumption, cost, size and installation effort, noise immunity, and activity detection. Last is provided a summary of advantages and disadvantages of each technique to help designing and improving tagless indoor person localization systems.