Real-time locating system: Difference between revisions

The physical layer of RTLS technology is usually some form ofoften [[radio frequency]] (RF) communication, but. someSome systems use optical (usually [[infrared]]) or acoustic (usually [[ultrasound]]) technology instead ofwith, or in additionplace toof RF., RTLS Tagstags. andAnd fixed reference points can be [[transmitter]]s, [[Receiver operating characteristic|receivers]], or both, resulting in numerous possible technology combinations.

The term RTLS was created (circa 1998) at the [[ID EXPO]] trade show by Tim Harrington (WhereNet), Jay Werb, (PinPoint), and Bert Moore, (Automatic Identification Manufacturers, Inc.(, AIM)). It was created to describe and differentiate an [[emerging technology]] that not only provided the automatic identification capabilities of active [[RFID]] tags, but also added the ability to view the location on a computer screen. It was at this show that the first examples of a commercial radio based RTLS system were shown by PinPoint and WhereNet. Although this capability had been utilized previously by military and government agencies, the technology had been too expensive for commercial purposes. In the early 1990s, the first commercial RTLS were installed at three healthcare facilities in the United States and were based on the transmission and decoding of [[infrared light]] signals from actively transmitting tags. Since then, new technology has emerged that also enables RTLS to be applied to passive tag applications.

RTLS are generally used in indoor and/or confined areas, such as buildings, and do not provide global coverage like [[global positioning system|GPS]]. RTLS tags are affixed to mobile items, such as equipment or personnel, to be tracked or managed. RTLS reference points, which can be either transmitters or receivers, are spaced throughout a building (or similar area of interest) to provide the desired tag coverage. In most cases, the more RTLS reference points that are installed, the better the location accuracy, until the technology limitations are reached.

A number of disparate system designs are all referred to as "real-time locating systems",. but there are twoTwo primary system design elements: are locating at choke points and locating in relative coordinates.

Another way to calculate relative location is ifvia [[Mobile tagging|mobile tags]] communicate directlycommunicating with eachone another. The tag(s) other,will then relay this information to a location processor.

SystemsSome thatsystems use locating technologies that do notcan't gopass through walls, such as infrared or ultrasound,. tendThese torequire beline moreof accuratesight in(or annear indoorline environmentof becausesight) onlyto tagscommunicate andproperly. receiversAs thata haveresult, linethey oftend sightto (orbe nearmore lineaccurate ofin sight)indoor can communicateenvironments.

RTLS can be used in numerous [[logistics|logistical]] or operational areas such asto:

* locate and manage assets within a facility, such as findinglocating a misplaced tool cart in a [[warehouse]] or medical equipment in a hospital

* notificationcreate ofnotifications newwhen locationsan object moves, such as an alert if a tool cart improperly has left the facility

* to combine identity of multiple items placed in a single location, such as on a pallet

* to locate customers, for example in a restaurant, for [[food delivery|delivery of food]] or service

* to maintain proper staffing levels of operational areas, such as ensuring guards are in the proper locations in a [[correctional facility]]

* to quickly and automatically account for all staff after or during an [[emergency evacuation]]

** [[Toronto General Hospital]] is looking at RTLS to reduce quarantine times after an infectious disease outbreak.<ref name="toronto">{{cite web|url=http://www.rfidjournal.com/article/articleview/9266/1/1/ |title=Toronto General Hospital Uses RTLS to Reduce Infection Transmission |publisherlast=Swedberg |first=Claire |website=RFID Journal |date=2012-02-28 |access-date=2016-04-28 |archive-url=https://web.archive.org/web/20120626233043/http://www.rfidjournal.com/article/articleview/9266/1/1/ |archive-date=2012-06-26 |url-status=dead}}</ref> After a recent [[SARS]] outbreak, 1% of all staff were quarantined. With RTLS, andthey would have more accurate data regarding who had been exposed to the virus, could havepotentially reducedreducing the need for quarantines.<ref name="toronto"/>

* toaid in [[Continual improvement process|process improvement]] efforts by automatically tracktracking and time stampstamping the progress of people or assets through a process, such as following a patient's emergency room wait time, time spent in the [[operating room]], and total time until discharge. Such a system can be used for [[process improvement]]

Several prominent [[labor union]]s have comespoken out against the use of RTLS systems to track workers, calling them "the beginning of [[AuthoritarianMass personalitysurveillance|Big Brother]]" and "an [[invasion of privacy]]".<ref>{{cite web|last=Coren |first=Michael J. |url=http://www.nextgov.com/health/2011/12/vas-real-time-location-system-a-way-to-improve-patient-safety-or-big-brother/50231/ |title=VA's Real-Time Location System: A way to improve patient safety, or Big Brother? |website=Nextgov.com |date=2011-12-05 |access-date=2016-04-28}}</ref>

* Passive RFID RTLS locating via steerable phased array antennae<ref>{{cite web|url=http://www.rfctrls.com/how-rf-controls-technology-paves-the-way-for-the-internet-of-everything/ |title=How RF Controls Technology Paves the Way for the "Internet of Everything." &#124; RF Controls |website=Rfctrls.com |date=2014-05-07 |access-date=2016-04-28 |archive-url=https://web.archive.org/web/20141120081422/http://www.rfctrls.com/how-rf-controls-technology-paves-the-way-for-the-internet-of-everything/ |archive-date=2014-11-20 |url-status=dead}}</ref>

* [[Radio beacon]]<ref name="rfidjournalevents1">{{cite web|url=http://www.rfidjournalevents.com/live2005/press_releases/RF%20Code.pdf |title=RFID Technology from Texas Instruments and RF Code Brings Service and Safety to Guests at Steamboat Ski Resort |website=Rfidjournalevents.com |date=2005-04-05 |access-date=2016-04-28 |archive-url=https://web.archive.org/web/20110715180355/http://www.rfidjournalevents.com/live2005/press_releases/RF%20Code.pdf |archive-date=2011-07-15 |url-status=dead}}</ref>

* Wide-over-narrow band<ref>{{cite web|url=http://www.essensium.com/lost_systemtechnology.html |title=LOST - Essensium's Real Time Location System by Essensium|access-date=April 8, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20101010042307/http://www.essensium.com/lost_system.html |archive-date=October 1015, 20102021 }}</ref>

* [[Bluetooth]]<ref>{{cite book|pages=2726–2731 |doi=10.1109/WCNC.2007.506 |websitepublisher=Ieeexplore.ieee.org |date=2007-03-15 |chapter=Enhancing Accuracy Performance of Bluetooth Positioning |last1=Son |first1=Le Thanh |last2=Orten |first2=Po |title=2007 IEEE Wireless Communications and Networking Conference |isbn=978-1-4244-0658-6 |s2cid=12464772 }}</ref><ref>

* Clustering in noisy ambience<ref>{{cite web|url=http://mll.csie.ntu.edu.tw/papers/collaboration_pervasive2006.pdf |title=Collaborative Localization: Enhancing WiFi-Based Position Estimation with Neighborhood Links in Clusters |access-date=March 31, 2009 |archive-url=https://web.archive.org/web/20100108081602/http://mll.csie.ntu.edu.tw/papers/collaboration_pervasive2006.pdf |archive-date=2010-01-08}}</ref><ref>{{cite book|pages=143–150 |doi=10.1109/PERCOM.2003.1192736 |websitepublisher=Ieeexplore.ieee.org |date=2003-03-26 |chapter=WLAN location determination via clustering and probability distributions |last1=Youssef |first1=M.A. |last2=Agrawala |first2=A. |last3=Udaya Shankar |first3=A. |title=Proceedings of the First IEEE International Conference on Pervasive Computing and Communications, 2003. (Per ''Com'' 2003) |isbn=978-0-7695-1893-0 |s2cid=2096671 }}</ref>

* [[Angle of departure]] (AoD) (e.g., Bluetooth direction finding<ref>{{Cite web|url=https://bluetoothle.wiki/direction_finding|title=direction_finding [Bluetooth® LE Wiki]|website=bluetoothle.wiki|access-date=2020-01-23}}</ref> features a mobile-centric RTLS architecture<ref>{{Cite web|url=https://quuppa.com/quuppas-role-regarding-the-new-bluetooth-sig-direction-finding-feature/|title=Quuppa's Role Regarding the New Bluetooth SIG Direction Finding Feature {{!}} Real-Time Locating System (RTLS)|date=2019-02-14|website=Quuppa|language=en-US|access-date=2020-01-23}}</ref> - see US 7376428 B1)

The basic issues of RTLS are standardized by the [[International Organization for Standardization]] and the [[International Electrotechnical Commission]] under the ISO/IEC 24730 series. In this series of standards, the basic standard ISO/IEC 24730-1 identifies the terms describing a form of RTLS used by a set of vendors, but does not encompass the full scope of RTLS technology.

In RTLS application in the healthcare industry, various studies were issued discussing the limitations of the currently adopted RTLS. Currently used technologies RFID, Wi-fi, UWB, all RFID based are hazardous in the sense of interference with sensitive equipment. A study carried out by Dr Erik Jan van Lieshout of the Academic Medical Centre of the University of Amsterdam published in ''JAMA'' (''Journal of the American Medical Equipment'')<ref>{{cite web|url=http://jama.jamanetwork.com/article.aspx?articleid=182113 |title=JAMA Network &#124; JAMA &#124; Electromagnetic Interference From Radio Frequency Identification Inducing Potentially Hazardous Incidents in Critical Care Medical Equipment |website=Jama.jamanetwork.com |access-date=2016-04-28}}</ref> claimed "RFID and UWB could shut down equipment patients rely on" as "RFID caused interference in 34 of the 123 tests they performed". The first Bluetooth RTLS provider in the medical industry is supporting this in their article: "The fact that RFID cannot be used near sensitive equipment should in itself be a red flag to the medical industry".<ref>{{cite web|url=http://www.locatible.com/blog/rfid-and-uwb-dead-medical-industry/ |title=RFID Dead in the Medical Industry? &#124; |website=Locatible.com |access-date=2016-04-28}}</ref> The RFID Journal responded to this study not negating it rather explaining real-case solution: "The Purdue study showed no effect when ultrahigh-frequency (UHF) systems were kept at a reasonable distance from medical equipment. So placing readers in utility rooms, near elevators and above doors between hospital wings or departments to track assets is not a problem".<ref>{{cite web|url=http://www.rfidjournal.com/articles/view?4198 |archive-url=https://web.archive.org/web/20130420012804/http://www.rfidjournal.com/articles/view?4198 |url-status=dead |archive-date=April 20, 2013 |title=Good and Bad News About RFID in Hospitals |date=21 July 2008 |publisher=RFID Journal |access-date=2016-04-28}}</ref> However the case of ”keeping at a reasonable distance” might be still an open question for the RTLS technology adopters and providers in medical facilities.

In many applications it is very difficult and at the same time important to make a proper choice among various communication technologies (e.g., RFID, WiFi, etc.) which RTLS may include. Wrong design decisiondecisions made at early stages can lead to catastrophic results for the system and a significant loss of money for fixing and redesign. To solve this problem a special methodology for RTLS design space exploration was developed. It consists of such steps as modelling, requirements specification, and verification into a single efficient process.<ref>{{cite journal|title=A methodology for design space exploration of real-time location systems.|author1=Kirov D.A. |author2=Passerone R. |author3=Ozhiganov A.A. |journal=Scientific and Technical Journal of Information Technologies, Mechanics and Optics|volume=15|issue=4|pages=551–567 |year=2015|doi=10.17586/2226-1494-2015-15-4-551-567|doi-access=free}}</ref>

* [https://books.google.com/books?id=aV3LBQAAQBAJ Local Positioning Systems: LBS applications and services], Krzysztof Kolodziej & Hjelm Johan, CRC Press Inc (2006)