CentiTrack: Towards Centimeter-Level Passive Gesture Tracking with Commodity WiFi

TL;DR

CentiTrack is a novel passive gesture tracking system using only three commodity WiFi devices, achieving centimeter-level accuracy without extra hardware or sensors by denoising CSI signals and applying advanced signal processing algorithms.

Contribution

This work introduces CentiTrack, the first system to achieve centimeter-level passive gesture tracking with standard WiFi devices, eliminating the need for specialized hardware or prior signal learning.

Findings

Achieves centimeter-level tracking accuracy.

Operates with only three commodity WiFi devices.

Outperforms existing methods in accuracy, range, and cost.

Abstract

Gesture awareness plays a crucial role in promoting human-computer interface. Previous works either depend on customized hardware or need a priori learning of wireless signal patterns, facing downsides in terms of the privacy concern, availability and reliability. In this paper, we propose CentiTrack, the first centimeter-level passive gesture tracking system that works with only three commodityWiFi devices, without any extra hardware modifications or wearable sensors. To this end, we first identify the Channel State Information (CSI) measurement error sources in the physical layer process, and then denoise CSI by the complex ratio between adjacent antennas. Principal Component Analysis (PCA) is further adopted to separate the reflected signals from noises. Benchmark experiments are conducted to verify that the phase changes of denoised CSI are proportional to the length changes of dynamic path reflected off the hand. In addition, we adopt the Multiple Signal Classification (MUSIC) algorithm to estimate the Angle-of-Arrivals (AoAs) of dynamic paths, and then locate the initial position of hands with triangulation. We also propose a novel static componnets elimination algorithm for tracking correction by eliminating the components unrelated to motion. A prototype of CentiTrack is fully realized and evaluated in various real scenarios. Extensive experiments show that CentiTrack is superior in terms of tracking accuracy, sensing range and device cost, compared with the state-of-the-arts.