Wi-Fi localization achieves meter-level accuracy on campus network
Meter-Level Wi-Fi RTT Localization on a Production Enterprise WLAN
Networking and Internet Architecture
Summary
Indoor location tracking using Wi-Fi signals usually needs special equipment or setups. This study shows that everyday Wi-Fi routers in a university network can locate devices to about one meter accuracy without extra hardware changes. The researchers tested this on several phones across an office space with different physical obstructions. They found that fixed calibration for all devices doesn’t work well, suggesting smarter software adjustments for each router instead of new equipment.
What this means in practice
- •For enterprise network administrators: Use existing enterprise Wi-Fi networks for accurate indoor positioning without needing hardware upgrades or manual calibration.
- •For facility management teams: Track assets or personnel inside office buildings using current Wi-Fi infrastructure for meter-level accuracy during normal operations.
Authors
Enguang Fan, Binh Minh Tran, Klara Nahrstedt
Abstract
Wi-Fi Fine Time Measurement (FTM) promises indoor localization by reusing access points (APs) already deployed for connectivity, but prior evaluations mostly use APs purpose-deployed or calibrated for ranging, leaving it unclear whether a production enterprise WLAN can provide useful localization without localization-specific infrastructure. We evaluate Wi-Fi round-trip time (RTT) localization on IllinoisNet, a live campus WLAN whose APs were placed for coverage and capacity. Using five commodity Android phones at 10 static locations across a 50 m x 30 m office floor spanning LOS, NLOS, and multipath conditions, weighted nonlinear least squares achieves a median error of 1.21 m and a 90th-percentile error of 2.68 m, with no AP replacement, repositioning, or ranging calibration. Residuals vary in magnitude and sign across APs and propagation conditions, suggesting a single global correction is insufficient and motivating AP-aware software calibration rather than new localization-specific infrastructure.