Articles


Real-Time Location System:
what they are and which benefits they can bring


What is RTLS?

The acronym RTLS refers to a Real-Time Location System, that is an hardware/software infrastructure based on IoT (Internet of Things) technologies that allows to identify, locate and trace individual objects or people present in a given context (such as, for example, a logistics site, a factory or a hospital).
BlueUp, innovative SME operating in the IoT and RTLS sectors since 2014, has created the acronym LAPS (Local Area Positioning System) which generalizes the concept of Indoor Positioning System (IPS) and refers to RTLS capable of locating and tracking people and/or objects in a spatially limited context, which can be indoor (hospital, warehouse, etc...) or outdoor (parking) or both (production site with outdoor warehouse).
An RTLS is not limited to just acquiring location data; thanks to sensors installed on the devices, it can also detect data of different nature, for example, the status of what is being tracked (movement, alarm events, ...) or environmental parameters (temperature, humidity, ...). The acquisition of this large amount of data in real time makes possible to obtain all the information necessary to create a real "digital twin", that is a virtual representation of a given physical environment.
In the Industry 4.0 paradigm, developing a Digital Twin means testing and understanding how the systems we are monitoring behave in a virtual simulation space. In the case of Digital Twins based on RTLS, starting from the position, movement and status data of assets or people, it is possible to improve a series of processes: reduce movement times and optimize routes, increase worker safety, acquire visibility on internal processes, increase operational efficiency, increase punctuality and the level of transparency of services provided to customers.
Le soluzioni RTLS trovano applicazioni in svariati ambiti:
Industry 4.0
Logistics
Healthcare
Smart Buildings

Specifically for applications related to production and logistics, there are many advantages brought by the adoption of RTLS solutions.
Improvement of logistics activities: by monitoring the position and movements of assets and people (operators/visitors) it is possible to obtain a marked improvement in logistics activities, reducing search times, eliminating the loss of tools and materials, automating the inventory.
Monitoring of production activities: the collection of data during the production process allows to check the progress, prevent errors, improve processes by eliminating bottlenecks.
Greater safety at work: thanks to RTLS it is possible to make workplaces safer, monitoring the position and status of lone workers or verifying unauthorized or uncontrolled access to areas at risk of safety. Thanks to the integration of sensors, it is possible to detect and notify alarm events in real time, such as bumps or falls.
Monitoring of environmental parameters: an RTLS system can be seen as a distributed network of wireless sensors capable of estimating not only the position data, but also of monitoring physical or environmental quantities: for example, it is possible to monitor the indoor climate and air quality to guarantee workers a healthy and comfortable work environment.

The components of an RTLS

RTLS systems constitute an hardware and software infrastructure which is made up of some basic components: tags, antennas, localization software.


Tag
Tags are wireless electronic devices that are applied to the objects/people to be tracked.
Tags are typically active devices, equipped with a battery, capable of autonomously sending information (unique identifier and any status information, such as battery level) to the antennas.
In the case of sensor integration, tags can also transmit physical or environmental parameters, such as temperature, together with their unique identifier.

Antennas
The antennas (also called "locators" or "anchors") are the fixed devices that make up the hardware localization infrastructure of the system.
The antennas, which receive the signals from the tags, are installed in a fixed position (on the ceiling, on the wall, on poles, ...), in order to guarantee the ideal radio coverage within the operating environment. Antennas typically require mains power, although solutions exist (such as the MeshCube platform ) where the antennas are battery powered.
The antennas, through a communication infrastructure (which can be wired or wireless, dedicated or shared), send the data received from the tags to a central system where the localization software resides, and which calculates the position of the individual tags in real time.

Localization software
The localization software (Positioning Engine) is the heart of the system: it receives the raw data from the antennas and, using dedicated algorithms, calculates the position of the individual tags.
Localization software typically also integrates advanced features such as the operational configuration of tags or communication with external application systems via API in HTTP or MQTT format.


RTLS technologies

RTLS systems can work with different technologies (GPS, RFID, Wi-Fi, Bluetooth Low Energy or BLE, Ultra-Wide Band or UWB), which differ in terms of performance (precision and latency of the position data), complexity infrastructure and total cost, including not only hardware and software, but also design, installation and maintenance services.
Let's see in more detail how the different technologies work:
GPS is the favorite technology for location applications, and is now present in all mobile devices. In this case, the tag is equipped with a GPS receiver that receives signals from GPS satellites and uses them to determine the geographic location of the object or person, and tracking software is integrated within the tag itself. To transmit position information to a centralized supervision and control system, the tag must also be equipped with a long-range connectivity system, such as LTE, NB-IoT, LoRa.
The advantages of using GPS for RTLS are related to the global coverage and the possibility of using an existing infrastructure. However, GPS-based RTLS systems has some limitations related to the difficulty or impossibility of using them in indoor environments, high battery consumption and the cost of the tag. GPS technology is mainly used for tracking vehicles on a geographical scale.
RFID technology uses radio waves to communicate between a reader and an RFID tag attached to the monitored object or person. RF energy is also used to power (in the case of "passive" tags, or wake up in the case of "semi-active" tags) the RFID tag. The RFID readers are placed in the environment and emit radio waves which are picked up by the RFID tags, which respond with a unique identification number. The readers then receive the identification number from the tags and forward it to software which uses the identification number to determine the location of the tag.
The main advantages of RFID technology for RTLS are the low cost and low (or zero) power consumption of the tag. However, due to the reduced communication distance between the antenna and the tag and the fluctuations in the received power value at the antenna, this technology is not very suitable for distributed RTLS applications. It is typically used for punctual localization applications, such as transit control from gates.
The WiFi technology used for RTLS applications works through a network of WiFi access points (APs). Assets that are to be monitored are equipped with WiFi receivers, which collect signals from APs and use them to calculate their location based on the strength of the signal received from each AP.
The main advantage of WiFi technology is related to the possibility of using existing WLAN infrastructures, eliminating or reducing the cost for antennas. However, WiFi-based RTLS solutions suffer from limitations due to the high cost and high power consumption of tags, poor accuracy, and problems sharing the WLAN network with other devices.
In BLE (Bluetooth Low Energy) technology, tags periodically transmit a packet of BLE advertising, containing the tag's unique identifier. The package can be formatted according to standard technologies for BLE beacons (such as iBeacon or Eddystone) or with proprietary formats (as in the case of Quuppa technology). BLE receivers, sometimes referred to as "BLE gateways" or "BLE locators", are placed throughout the room, usually on the ceiling or wall. Based on the localization algorithms, the complexity, and consequently also the cost, of the BLE receivers varies:
• for RTLS systems based on RSSI (Received Signal Strength Indicator), that is the received power value, the receivers are simple BLE gateways, with WLAN or LAN interface;
• in the case of systems based on AoA (angle of Arrival), the locators are more complex and integrate antenna arrays with algorithms capable of calculating the direction of incidence of the BLE signal.
BLE technology has many advantages when used for RTLS applications: the reduced consumption and low cost of the tags, the high scalability, the possibility of offering extremely diversified solutions in terms of costs and performance, the high degree of integration with devices and sensors IoT adopting BLE as their communication technology.
Within the RTLS solutions that use BLE technology, we can also include solutions that adopt BLE compatible radios, but are not compliant with the BLE standard. Of particular interest among these solutions is the Mesh 2.4GHz technology, which makes possible to create localization systems characterized by a completely wireless infrastructure (the anchors are battery powered and communicate via radio via mesh), ensuring high simplicity and scalability and a lower total cost of implementation than most of the alternative technologies.
RTLS based on UWB (Ultra-Wide Band) is structured using UWB tags that transmit ultra-wideband signals (with a bandwidth greater than 500MHz) with low power. The use of UWB signals (i.e. short duration pulses, in the order of a few nsec or less), allows to calculate the distance between the tag and the UWB antenna by estimating the time of flight of the signal itself. There are several algorithms that use UWB technology, among which the main ones are:
ToF (Time of Flight), based on the time that elapses between the start of transmission by the tag and the start of reception of the response signal from the antenna (for this reason the methodology is also called TWR, Two-Way Ranging), a value which is proportional to the distance between the tag and the antenna;
TDoA (Time Difference of Arrival), in which the difference in the instant of arrival at the various receiving antennas of the signal transmitted by the tag is calculated, from which it is possible to estimate the absolute distance with respect to the various antennas.
The main feature of the UWB is its high precision in determining the tag's position in real time. However, UWB suffers from some limitations, including the high total cost of infrastructure, the higher cost of the tags compared to BLE, the high energy consumption of the tag, especially for applications with low latency tracking.

BlueUp RTLS solutions

The RTLS solutions offered by BlueUp are all based on the Bluetooth LE standard or compatible wireless protocols. In fact, among all the available technologies, BLE emerges as a key technology for RTLS applications thanks to a series of characteristics: flexibility, scalability, low cost, reduced energy consumption, integration with IoT systems.
BlueUp offers three different RTLS solutions that differ in performance, cost and installation complexity.

MeshCube is a unique solution on the market, with a completely wireless infrastructure based on a communication network in Wirepas Mesh 2.4GHz technology. With this technology all design, installation and wiring costs are reduced to almost zero, making it extremely economical and suitable for automatic inventory applications, asset tracking in logistics and hospitals, distributed monitoring using sensors.

LocateBLE allows the localization of assets and people in real time through algorithms based on RSSI (Received Signal Strength Indicator) and trilateration. The rewarding feature of LocateBLE is its independence from hardware: the platform, in fact, is designed to be compatible with multiple types of BLE antennas on the market: BLE beacon gateway, WiFi access point with BLE interface, Zigbee or mesh modules with support BLE extension. This flexibility makes LocateBLE suitable for a wide range of applications.

Finally, in case location accuracy is the key requirement, AccuRTLS is the ideal solution. AccuRTLS provides state-of-the-art performance, with real-time tracking and accuracy down to a few tens of centimeters in a real operating environment, thanks to RTLS BLE Angle of Arrival technology, developed by Quuppa, of which BlueUp has been a partner since 2017.
For this technology, BlueUp develops and produces Quuppa Approved tags, certified directly by Quuppa to be fully compatible with functional, performance and mechanical level with Quuppa technology.


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