3D-WiFi: 3D Localization With Commodity WiFi

Recently, 3D localization has attracted intense interests with its enabled applications, such as smart healthcare, smart home, and smart robots. Conventional 3D localization technologies require to utilize the special-dedicated infrastructures with a large-scale deployment, which results in high cost. However, in order to accomplish an appealing tradeoff between location accuracy and infrastructure cost, designing and implementing a 3D localization system are still a challenging task to solve. To address this issue, we develop a novel 3D localization system by using commercial off-the-shelf (COTS) WiFi infrastructures at a low cost. First, we design a cost-effective hardware scheme to derive the orientation information for 3D localization. Then, we adopt a fusion method of multiple channel state information measurements to improve multipath resolution and identify the target direct path by the azimuth and elevation angle-of-arrival (AOA) and equivalent time-of-arrival estimations, which can be formulated as subspace-based sparse reconstruction with high accuracy. Finally, according to both azimuth and elevation AOA estimations of the target direct path, the target can be localized in 3D space at decimeter-level. We implement the proposed 3D localization system using COTS WiFi infrastructures and validate its performance with extensive evaluations in two indoor scenarios.