MetaSonic: Advancing Robot Localization with Directional Embedded Acoustic Signals

Indoor positioning in environments where GPS cannot be used is a fundamental technology for robotics navigation and human-robot interaction. However, existing vision-based localization systems cannot work in dark environments, and existing wireless or acoustic localization systems require specific transceivers, making them expensive and power-intensive — particularly challenging for micro-robots. This paper proposes a new metasurface-assisted ultrasound positioning system. The key idea is to use a low-cost passive acoustic metasurface to transfer any speaker into a directional ultrasound source, with the acoustic spectrum varying based on direction. This allows any microrobot with a simple, low-cost microphone to capture such modified sound to identify the direction of the sound source. We develop a lightweight convolutional neural network-based localization algorithm that can be efficiently deployed on low-power microcontrollers.

Anchor Deployment

Our localization scenarios are evaluated in the following three rooms: a 3.5 m × 4 m small room, a 2 m × 14 m lobby, and a 5 m × 12 m large room. Four anchors are deployed in each scene. The deployment of anchors is as follows.

Demo Video

The video demonstrates a scenario where four anchors are deployed in the environment. As the robot moves, the spectrograms of the four anchors, as perceived by the robot, dynamically change with variations in position.