The real-time search system (RTLS ) is used to identify and track the location of objects or people directly automatically, usually within a building or other area that there is. The wireless RTLS tag is attached to the object or used by people, and in most RTLS, the reference point still receives the wireless signal from the tag to determine its location. Examples of real-time localization systems include tracking cars through an assembly line, finding merchandise pallets in a warehouse, or finding medical equipment in a hospital.
The physical layer of RTLS technology is usually a form of radio frequency (RF) communication, but some systems use optical (usually infrared) or acoustic (usually ultrasound) technologies rather than or other than RF. Tags and reference points can still be transmitters, recipients, or both, resulting in many possible combinations of technologies.
RTLS is a form of local positioning system, and usually does not refer to GPS or to cell phone tracking. Location information usually does not include speed, direction, or spatial orientation.
Video Real-time locating system
Origin
The term RTLS was created (circa 1998) at the EXPO ID trade show by Tim Harrington (WhereNet), Jay Werb, (PinPoint), and Bert Moore (Automatic Identification Manufacturers, Inc. (AIM)). It was created to illustrate and differentiate new technologies that not only provide automatic identification capabilities of active RFID tags, but also add the ability to view locations on a computer screen. It was in this event that the first example of a commercial radio-based RTLS system is shown by PinPoint and WhereNet. Although this capability has been used previously by military and government agencies, the technology is too expensive for commercial purposes. In the early 1990s, the first commercial RTLS was installed in three health facilities in the United States, and was based on the transmission and decomposition of infrared light signals from active tag transmission. Since then, new technologies have emerged that also allow RTLS to be applied to passive tag applications.
Maps Real-time locating system
Finding the concept
RTLS is commonly used in indoor and/or limited areas, such as buildings, and does not provide global coverage such as GPS. The RTLS tag is pasted into a mobile item to be tracked or managed. The RTLS reference point, which can be either a transmitter or a receiver, is placed in the entire building (or similar interest area) to provide the desired tag coverage. In many cases, the more RTLS reference points are installed, the better the location accuracy, until the technological constraint is reached.
A number of different system designs are all referred to as "real-time location systems", but there are two main system design elements:
Find the choke point
The simplest form of a choke location is where the short distance ID signal of a moving tag is received by a single fixed reader in the sensory network, which indicates the accidental location of the reader and the tag. Alternately, choke point identifiers may be accepted by moving tags, and then forwarded, usually via a second wireless channel, to the location processor. Accuracy is usually determined by a sphere that is stretched with the transmitter or receiver range of the choke point. Use of directional antennas, or technologies such as infrared or ultrasound blocked by the room partition, can support multiple geometry choke points.
Find in relative coordinates
The tag ID signal is received by many readers on the sensory network, and the position is estimated using one or more location algorithms, such as trilateration, multilateration, or triangulation. Equivalently, the ID signal from some RTLS reference points may be received by the tag, and passed back to the location processor. Localization with multiple reference points requires that the distance between the reference point in the sensory network is known to find the tags appropriately, and the distance determination is called ranges.
Another way to calculate relative location is if the mobile tag communicates directly with each other, then passes this information to the location processor.
Location accuracy
RF trilateration uses the approximate range of multiple receivers to estimate the location of a tag. RF triangulation uses the angle at which RF signals arrive at multiple receivers to estimate the location of a tag. Many obstructions, such as walls or furniture, can distort the approximate range and angular readings that lead to various quality estimates of location. Estimation-based estimates are often measured in accuracy for a certain distance, such as 90% accurate for a distance of 10 meters.
Systems that use location technology that does not pass through walls, such as infrared or ultrasound, tend to be more accurate in the indoor environment because only tags and receivers that have a line of sight (or near line of sight) can communicate.
Apps
RTLS can be used various logistics or operational areas such as:
- locate and manage assets inside the facility, such as finding misplaced tool baskets in storage or medical equipment
- new location notifications, such as a warning if the tool basket does not properly leave the facility
- to merge the identity of multiple items placed in one location, as in the palette
- to find customers, for example in restaurants, for food delivery or services
- to maintain appropriate staff levels from the operational area, such as ensuring the guard is in the right location in a correctional facility
- is quickly and automatically responsible for all staff after or during emergency evacuation
- to automatically track and record the progress of people or assets through a process, such as following the patient emergency room waiting time, time spent in the operating room, and the total time to go home. Such a system can be used for process improvement
- clinical class location to support acute care capacity management
Privacy issues
RTLS can be seen as a threat to privacy when it is used to locate people. The newly declared human rights of self-determination of information provide the right to prevent one's identity and personal data from being disclosed to others, and also to include disclosure of locality, although this is not generally applicable in the workplace.
Several leading trade unions have opposed the use of the RTLS system to track workers who call them "the beginning of Big Brother" and "privacy invasion". The general strategy for overcoming opposition to this system is often similar to the following. However, this loss of privacy can be overcome by other benefits for staff. For example, the Toronto General Hospital sees RTLS to reduce quarantine time after an outbreak of a contagious disease. After the recent SARS outbreak, 1% of all staff were quarantined, and more accurate data on who is exposed to the virus may reduce the need for quarantine.
Type of technology used
There are various system and design concepts to provide real-time location.
- Active radio frequency identification (RFID On)
- Active radio frequency identification - Infrared hybrid (RFID-IR On)
- Infrared (IR)
- Optical location
- Identify low frequency tagging
- Identify semi-active (semi-active RFID) radio frequency
- Passive RFID RTLS finds via Steerable Phased Array Antennae
- Radio catch,
- Ultrasound Identification (US-ID)
- Ultrasonic start (US-RTLS)
- Ultra-wide band (UWB)
- Bands are narrow-width
- Wireless Local Area Network (WLAN, Wi-Fi)
- Bluetooth,
- Group in noisy mood,
- The bivalent system
The general model for selecting the best solution to locating problems has been built at Radboud University of Nijmegen. Many of these references do not conform to the definitions given in international standardization with ISO/IEC 19762-5 and ISO/IEC 24730-1. However, some aspects of real-time performance are presented and placement aspects are discussed in the context of absolute coordinates.
Start and angulation
Depending on the physical technology used, at least one and often multiple combinations of range and/or angulation methods are used to determine the location:
- Arrival corner (AoA)
- Line-of-sight (LoS)
- Time of arrival (ToA)
- Multilateration (Difference of arrival time) (TDoA)
- Flight time (ToF)
- Two-way (TWR) corresponds to Nanotron patent
- Two Symmetrical Sides - Two Direction Directions (SDS-TWR)
- Near-field electromagnetic field (NFER)
Errors and accuracy
The real-time location is affected by various errors. Many of the main reasons relate to the physics of locating systems, and can not be reduced by improving technical equipment.
- No or no direct response
Many RTLS systems require direct and clear view visibility. For such systems, where there is no visibility from the mobile tag to the fixed node there will be no invalid results or results from the search engine. This applies to satellite locations as well as other RTLS systems such as arrival angle and arrival time. Fingerprinting is a way to address visibility issues: If the location in the tracking area contains different measurement fingerprints, the line of sight is not always necessary. For example, if each location contains a unique combination of signal strength readings from the transmitter, the location system will function properly. This is true, for example, with some RTLS-based Wi-Fi solutions. However, having a fingerprint of different signal strengths at each location usually requires relatively high transmitter saturation.
- Incorrect location
The measured location may appear completely corrupted. This is generally the result of a simple operational model to compensate for the plurality of sources of error. This proves impossible to serve the right location after ignoring the error.
- Search the backlog
Real time is not a registered trademark and does not have an inherent quality. Various screen offerings under this term. Because movement causes a change of location, it can not be denied the latency time to calculate a new location may be dominant with regard to movement. Neither the RTLS system that requires waiting for new results is not worth the money or operational concept requiring a faster location update does not match the selected system approach.
Locations will never be reported exactly , since real-time terms and precise terms directly conflict with aspects of measurement theory and also the precise term precision and the terms costs are contradictory in the economic aspects. That's not a precision exception, but limitations with higher speeds can not be avoided.
- Stable location error
Recognizing steadily reported locations other than physical presence generally indicates inadequate redundancy and visibility issues along the length of at least one link from the population anchor to a cellular transponder. Such effects are also caused by insufficient concepts to compensate for the need for calibration.
- The jitter location
Noise from various sources has an uncertain influence on yield stability. The goal is to provide a stable view of increasing latency as opposed to real time requirements.
- Leap location
Because mass-containing objects have limitations to jump, they are largely beyond physical reality. The reported location leap is not visible to the object itself generally indicates an improper modeling with the location machine. Such effects are caused by changes in the dominance of various secondary responses.
- Location creep
The location of live objects is reported to move, as soon as the action is taken biased by secondary path reflections with increasing weight over time. Such an effect is caused by a modest average and the effect indicates the absence of discrimination against the first echo.
Standard
ISO/IEC
The basic problem of RTLS is standardized by International Organization for Standardization and International Electrotechnical Commission, under ISO/IEC 24730 series. In this set of standards, ISO/IEC 24730-1 basic standards identify terms that describe the RTLS form used by a set of vendors, but do not cover the full range of RTLS technologies.
Currently some standards are published:
- ISO/IEC 19762-5: 2008 Information technology - Automatic identification and data collection techniques (AIDC) - Synced vocabulary - Part 5: Finding the system
- ISO/IEC 24730-1: 2014 Information technology - Real time searching system (RTLS) - Part 1: Application programming interface (API)
- ISO/IEC 24730-2: 2012 Information Technology - Real-Time Location System (RTLS) - Part 2: Spectrum Direct Distribution Spectrum (DSSS) 2.4 GHz air interface protocol
- ISO/IEC 24730-5: 2010 Information technology - Real-time search system (RTLS) - Part 5: Spectrum spread spectrum (CSS) on 2.4 GHz air interface
- ISO/IEC 24730-21: 2012 Information technology - Real-time location system (RTLS) - Section 21: Spectrum Direct Density Spectrum (DSSS) 2.4 GHz air interface protocols: Transmitters operating with single spread codes and using encryption DBPSK data and BPSK deployment schemes
- ISO/IEC 24730-22: 2012 Information technology - Real-time location system (RTLS) - Section 22: Spectrum Direct Density Spectrum (DSSS) 2.4 GHz air interface protocol: Transmitters that operate with multiple scattered codes and use encoding QPSK data and offset scheme Walsh offset QPSK (WOQPSK)
- ISO/IEC 24730-61: 2013 Information Technology - Real Time Location System (RTLS) - Section 61: Frequency repetition of the Ultra Wide Band frequency (UWB) airframe loop frequency
- ISO/IEC 24730-62: 2013 Information technology - Real time location system (RTLS) - Section 62: Frequency repetition of high frequency pulses Ultra Wide Band air interface (UWB)
These standards do not specify specific methods for computing locations, or location measurement methods. This can be defined in specifications for trilateration, triangulation or hybrid approaches for trigonometric computations for planar or spherical models from terrestrial regions.
INCITS
- INCITS 371.1: 2003, Information Technology - Real Time Finder System (RTLS) - Part 1: 2.4 GHz Air Interface Protocol
- INCITS 371.2: 2003, Information Technology - Real Time Finder System (RTLS) - Part 2: 433-MHz Air Interface Protocol
- INCITS 371.3: 2003, Information Technology - Real Time Finder System (RTLS) - Part 3: Application Programming Interface
More restrictions and discussion
In RTLS applications in the Healthcare industry, various studies are published addressing the limitations of RTLS adopted today. Currently the technology used RFID, Wi-fi, UWB, all based on RFID is dangerous in the sense of interference with sensitive equipment. A study by Dr Erik Jan van Lieshout of the University of Amsterdam's Academic Medical Center published in JAMA (Journal of American Medical Equipment ) claims "RFID and UWB" can shut down patient equipment rely on "as" RFID causes interference on 34 of the 123 tests they perform. "The first RTLS Bluetooth providers in the medical industry supported this in their article:" The fact that RFID can not be used near sensitive equipment should in itself be a red flag for medical industry. "The RFID journal responded to this study and did not exclude it by explaining the real solution:" The Purdue study showed no effect when the ultrasonic frequency (UHF) system was kept at a reasonable distance from medical equipment. So putting the reader in the utility room, near the elevator and the door above between the hospital wing or department to track assets is not a problem. "But the case of" maintaining a reasonable distance "may still be an open question for RTLS adopters and technology providers in medical facilities.
In many applications it is very difficult and at the same time it is important to make the right choice among the various communication technologies (eg, RFID, WiFi, etc.) that RTLS might include. incorrect design decisions made in the early stages can lead to catastrophic results for the system and significant loss of money to repair and redesign. To solve this problem, a special methodology for RTLS design space exploration was developed. It consists of steps such as modeling, requirements specification and verification into an efficient process.
See also
- Awareness context
- Indoor positioning system
- Location awareness
- Positioning technology
- Track and track
- Vehicle tracking system
References
Further reading
- Malik, Ajay (2009). RTLS For Dummies . Wiley. p.Ã, 384. ISBNÃ, 978-0-470-39868-5. Ã,
- Indoor Geolocation Using Wireless Local Area Networks (Berichte Aus Der Informatik), Michael Wallbaum (2006)
- Local Positioning System: LBS apps and services, Krzysztof Kolodziej & amp; Hjelm Johan, CRC Press Inc. (2006)
External links
- Geographic location-based app development
- A real-time location primer search
- International Lobby Statement on Real Location Determination
- ISO JTC1 (TC122) SC31 WG5 Homepage in RTLS
- ISO JTC1 (TC122) website SC31 WG5 at MIIM
- Companies that drive international standardization on eg. RFID and RTLS in the US
- The actual schedule and scope of the RTLS standardization in ISO JTC1, TC122 and SC31
- funding Car-to_Car's communications program from the European Union
- The Non-Line-of-Sight Localization System by CMR @ UNSW
Source of the article : Wikipedia
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