Range Variation Monitoring with Wireless Two-Way Interferometry (Wi-Wi)

TL;DR

This paper presents a simple, low-cost wireless two-way interferometry technique for millimeter-precision range variation monitoring between remote sites, leveraging off-the-shelf modules and analyzing signal propagation delays.

Contribution

It introduces a novel, easy-to-implement method for precise distance variation measurement using wireless communication signals, suitable for integration into standard wireless chips.

Findings

Achieved millimeter-precision range variation monitoring.

Demonstrated a low-cost, simple alternative to existing systems.

Potential for integration into wireless communication hardware.

Abstract

We demonstrated a simple technique for monitoring range variation with millimeter-precision between two remote sites using off-the-shelf wireless communication modules. The need for the flexible positioning of wireless devices is significantly increasing as more devices are being connected and new services are being developed that require devices to collaborate with one another. We showed that one can monitor the distance variation by analyzing the propagation delay of the wireless communication signal between devices. We previously reported a technique for synchronizing clocks with picosecond precision by monitoring the time variation of two rubidium clocks located at remote sites. Precise measurement of the propagation time variation was necessary for precise synchronization of the clocks, and we used this information to estimate the distance with high precision. In a localized situation, our technique makes it easy to implement a millimeter-precision measurement system. Furthermore, it is less complex in terms of system design and can be a low-cost alternative to existing systems that require precise position measurement. We envision that this demonstrated protocol will be implemented in wireless communication chips and microprocessing units.