ReflecTrack: Enabling 3D Acoustic Position Tracking Using Commodity Dual-Microphone Smartphones
summary
Uses a smartwatch or earbud to emit inaudible FMCW and leverages a nearby reflective surface to create mirror microphones so a dual‑microphone phone obtains four ranges for triangulation. Implements an echo‑aware FMCW pipeline with a triangular chirp and CFAR peak detection to separate direct and echo paths. Built and tested system achieves median error 28.4 mm in a 60 cm cube and 22.1 mm in a 30 cm cube, works with everyday surfaces, tolerates noise and motion up to ~3 m/s, and powers 3D input, gesture and VR demos.
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chapters (14)
- 0:00Intro
- 0:243D tracking is not easily accessible in daily life
- 0:54Audio hardware on commodity mobile devices
- 1:11Acoustic Tracking Solutions on Mobile Devices
- 1:383D Tracking with Two Microphones
- 2:43Leveraging Echoes
- 3:00Echo-aware FMCW
- 3:11Triangular Chirp based FMCW
- 3:32Constant False Alarm Rate (CFAR) Peak Detection
- 4:04Triangulation
- 4:49Evaluation Study
- 5:45User Study
- 6:38Applications
- 6:57Contributions