An Efficient Single-Anchor Localization Method Using Ultra-Wide Bandwidth Systems

Abstract

Ultra-wideband technology has the merits of high temporal resolution and stability, and it has been widely used for high-accuracy localization and tracking. However, most ultra-wideband localization systems need multiple anchors for trilateration, which results in high system cost, large messages overhead, and insufficient extraction of information. In this paper, we propose a single-anchor localization (SAL) mehtod that achieves high-accuracy multi-agent localization with high efficiency. In the proposed method, the anchor broadcasts the first two messages and then each agent responds one message to the anchor (quasi-)simultaneously. Based on the received message with superpositioned agent responses, the time-of-flight and angle-of-arrival information from all agents to the anchor can be extracted altogether. We implement the localization system in two indoor environments, and show that the proposed method can achieve decimeter-level accuracy for multiple agents using three messages. Our method provides design guidelines for high-accuracy and high-efficiency multi-agent localization systems.

Anchor-oriented Time and Phase-based Concurrent Self-localization using UWB Radios

“…There is a body of research on improving the performance of wireless systems under interference, including studies on avoiding interference by TDMA schemes, ALOHA, or combining localization and communication traffic [12]; mitigating interference [13], [14]; and exploiting interference [15]- [17]. More recently, researchers used (quasi-)simultaneous transmissions with UWB radios for indoor localization to increase air time efficiency by simultaneously extracting time of arrival (TOA) or phase of arrival (POA) of multiple transmitters from the combined from the channel impulse response (CIR) of the concurrently received packets [5]- [11], [18].…”

“…Traditional ranging systems make use of the ability of UWB radios to measure TOA of the arriving packet. Concurrency-based ranging systems measure range with multiple UWB transceivers by measuring the difference between TOA of later arriving packets and TOA of the first arriving packet [5], [7], [9], [18]. TOA-based solutions are not scalable in terms of the number of tags as they require two-way message passing between anchors and tags, and CIR can only accommodate a limited number of concurrent signals.…”

“…Our work explores the possibility of combining the idea of intra-anchor concurrency with inter-anchor concurrency (packets concurrently transmitted from multiple anchors) to measure AOA from multiple dual-UWB radio anchors on single-antenna tags. Another research study combines AOA with ranging (TOA) to build a single-anchor localization system [18]. However, this solution is not scalable in terms of the number of tags as it requires two-way message passing between anchors and tags, and CIR can only accommodate a limited number of concurrent signals.…”

Ultra-wideband Concurrent Ranging

“…Recently, these works have also inspired the use of UWB concurrent transmissions with angleof-arrival (AoA) localization. In Reference [60], a multi-antenna anchor sends a poll to which mobile nodes in range reply concurrently, allowing the anchor not only to measure their distance but also the AoA of their signals; combining the two enables the anchor to estimate the position of each node. The techniques we proposed in this article (Section 5) addressing the TX uncertainty, clock drift, and unreliability caused by packet loss, are applicable and likely beneficial also for this AoA technique.…”

Power Allocation and Parameter Estimation for Multipath-based 5G Positioning

“…An algorithm for localization and synchronization of cooperating full-duplex agents using a single-anchor is developed in [16]. The authors of [17] propose a protocol and an accompanying algorithm that enables a single-anchor to (quasi-)simultaneously receive messages from multiple agents in order to localize them using TOA and AOA measurements. The proposed approach is verified on an experimental setup.…”