Ultra-wideband Concurrent Ranging

Abstract

We propose a novel concurrent ranging technique for distance estimation with ultra-wideband (UWB) radios. Conventional schemes assume that the necessary packet exchanges occur in isolation to avoid collisions. Concurrent ranging relies on the overlapping of replies from nearby responders to the same ranging request issued by an initiator node. As UWB transmissions rely on short pulses, the individual times of arrival can be discriminated by examining the channel impulse response (CIR) of the initiator transceiver. By ranging against N responders with a single, concurrent exchange, our technique drastically abates network overhead, enabling higher ranging frequency with lower latency and energy consumption w.r.t. conventional schemes. Concurrent ranging can be implemented with a strawman approach requiring minimal changes to standard schemes. Nevertheless, we empirically show that this limits the attainable accuracy, reliability, and therefore applicability. We identify the main challenges in realizing concurrent ranging without dedicated hardware and tackle them by contributing several techniques, used in synergy in our prototype based on the popular DW1000 transceiver. Our evaluation, with static targets and a mobile robot, confirms that concurrent ranging reliably achieves decimeter-level distance and position accuracy, comparable to conventional schemes but at a fraction of the network and energy cost.

High-Accuracy Ranging and Localization With Ultrawideband Communications for Energy-Constrained Devices

“…2) The Energy Efficiency of UWB devices: To the best of our knowledge, we are the first to compare the power and energy consumption of devices implementing the LRP and HRP PHYs as defined in the IEEE 802.15.4 standard [4]. Energy efficiency is starting to be a concern in UWB devices and, recently, concurrent ranging has been proposed as a solution to minimize the energy consumption in localization tasks at the application level [48]. Using this method, a tag can compute its location based on the time difference of arrival between multiple anchors' responses which are processed in a single message (rather than 2 × N messages, where N is the number of anchors, as in SS-TWR-based trilateration).…”

Principles and Trends of UWB Positioning Technology

“…특별히, UWB에서 TWR이 부각되는 이유는 UWB가 광대역 펄스를 사용함으로써 ToF 측정이 타 통 신방식에 비해 보다 정밀하기 때문이다 [8], [9] . [20], [21] . [22]～ [25] .…”

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

“…Concurrent TOA/TDOA systems suffer from lower accuracy caused by TX scheduling uncertainty in UWB radios [5], [7], [9]. Solutions for TX scheduling uncertainty problem either assume certain implementation (wired correction) or have one-packet cycle delay (wireless correction) [8]; or do not support moderately large transmission delays due to clock drift [19].…”