WiBall: A Time-Reversal Focusing Ball Method for Indoor Tracking

TL;DR

WiBall is a novel indoor tracking system that uses radio signal time-reversal focusing to achieve high accuracy without calibration, working effectively in non-line-of-sight conditions and scalable for multiple users.

Contribution

WiBall introduces a calibration-free indoor tracking method leveraging radio time-reversal focusing, enabling accurate non-line-of-sight tracking with minimal hardware.

Findings

Achieves decimeter-level accuracy in various environments.

Works effectively in non-line-of-sight scenarios.

Supports multiple users with a single device pair.

Abstract

With the development of the Internet of Things technology, indoor tracking has become a popular application nowadays, but most existing solutions can only work in line-of-sight scenarios, or require regular re-calibration. In this paper, we propose WiBall, an accurate and calibration-free indoor tracking system that can work well in non-line-of-sight based on radio signals. WiBall leverages a stationary and location-independent property of the time-reversal focusing effect of radio signals for highly accurate moving distance estimation. Together with the direction estimation based on inertial measurement unit and location correction using the constraints from the floorplan, WiBall is shown to be able to track a moving object with decimeter-level accuracy in different environments. Since WiBall can accommodate a large number of users with only a single pair of devices, it is low-cost and easily scalable, and can be a promising candidate for future indoor tracking applications.