Time Difference of Arrival Extraction from Two-Way Ranging

TL;DR

This paper presents a method to extract Time Difference of Arrival information from Two-Way Ranging processes, enabling scalable passive tag localization without synchronized anchors by accounting for clock offsets and drifts.

Contribution

It introduces a novel approach to derive TDoA data from Two-Way Ranging, removing the need for static or synchronized anchors in passive localization.

Findings

Formal error bounds are derived for the extraction method.

The approach works with both Double-Sided and Single-Sided Two-Way Ranging.

Additional carrier frequency offset estimation enhances accuracy.

Abstract

Two-Way Ranging enables the distance estimation between two active parties and allows time of flight measurements despite relative clock offset and drift. Limited by the number of messages, scalable solutions build on Time Difference of Arrival to infer timing information at passive listeners. However, the demand for accurate distance estimates dictates a tight bound on the time synchronization, thus limiting scalability to the localization of passive tags relative to static, synchronized anchors. This work describes the extraction of Time Difference of Arrival information from a Two-Way Ranging process, enabling the extraction of distance information on passive listeners and further allowing scalable tag localization without the need for static or synchronized anchors. The expected error is formally deducted. The extension allows the extraction of the timing difference despite relative clock offset and drift for the Double-Sided Two-Way Ranging and Single-Sided Two-Way Ranging with additional carrier frequency offset estimation.