Real-Time Location System (RTLS)

What Is a Real-Time Location System (RTLS)?

Real Time Location System (RTLS) is a technology that accurately determines the real-time location of objects or people within a given area.

It is not a single, specific technology but rather a concept that can be achieved using various systems and methods for asset tracking and management. RTLS systems are designed to provide timely and precise location data, enabling organizations to make informed decisions based on the movement and whereabouts of assets, inventory, or individuals.

RTLS finds applications across different industries, with specific use cases in employee tracking and monitoring high-value assets. While it is utilized in various sectors, it is particularly prominent in healthcare, manufacturing, and mining industries.
 

How to Implement Real-Time Location System (RTLS)?

Implementing an RTLS system involves several key components and choices, including:

1. Transponders: Transponders are devices attached to objects or individuals to uniquely identify them within the RTLS system. Depending on the chosen technology and application requirements, transponders can take the form of RFID tags, Bluetooth beacons, smart devices, Wi-Fi tags, GNSS/GPS tags, ultrasound tags, infrared tags, or other specialized devices. These transponders respond to signals from receivers or readers.
2. Receivers: Receivers are hardware components equipped with a power source that captures signals from transponders and forwards the collected data to host computers or networked/cloud databases. Receivers can vary in type, including readers, location sensors, access points, beacons, and smart devices, depending on the selected technology and application.
3. Software: RTLS systems rely on software components to interpret and process the location data collected by receivers and transponders. The software may include firmware residing on the hardware, application software running on host computers or servers, and middleware used to connect firmware and application software. These software components work in tandem to create the desired functionality for the RTLS system.

RTLS Coverage Options

RTLS systems offer various coverage options, allowing organizations to tailor their tracking solutions to specific needs:

• Wide Area Coverage: This option involves locating objects or people on a global scale using global coordinates, often facilitated by technologies like GNSS (GPS). It is suitable for tracking items traveling across large distances, such as cargo containers.
• Local Area Coverage: Local area coverage focuses on tracking objects or people within a building or facility that shares the same network. This is commonly used in indoor environments for asset tracking within a specific location.
• Zonal Coverage: Zonal coverage targets tracking within predefined zones, such as rooms or offices within a larger area. It involves setting up hardware at intervals based on read range and read obstacles, offering precise location data within these zones.
• Choke Points: Choke points refer to areas that items or individuals must pass through for regular business operations, like doorways or entrances/exits. These narrower coverage zones are used to determine the location of items as they pass through specific points, often in warehouse or security applications.

What Technology Can Be Used for RTLS?

When implementing an RTLS system, organizations must select the most suitable technology for their specific application. Some prevalent technologies used for successful RTLS applications include:

• Bluetooth Low Energy (BLE): BLE technology utilizes beacons or tags that continuously broadcast signals to the surrounding area. These signals are picked up by devices with Bluetooth capabilities, such as receivers or smart devices, enabling real-time tracking within a defined area.
• GNSS/GPS: Global Navigation Satellite System (GNSS), commonly referred to as GPS, uses satellite signals to provide wide-area coverage and global positioning. GNSS tags calculate their location based on signals received from multiple satellites, making it ideal for outdoor tracking.
• Infrared Radiation: Infrared tags emit signals within a room or zone, making it suitable for room-level positioning. Receivers equipped with infrared sensors capture these signals and relay the data to host computers or databases.
• Passive RFID: Passive Ultra-High Frequency (UHF) RFID systems can be used for choke point, zonal, or local area coverage. By strategically placing RFID readers and antennas, organizations can track items as they pass through specific areas or zones.
• Active RFID: Active UHF RFID is typically used for local area and zonal coverage, especially in large outdoor environments. Active RFID tags continuously broadcast signals, and receivers capture this data to determine the location of tagged assets.
• Ultrasound Radiation: Ultrasound tags emit acoustic signals that are received by ultrasound receivers. This technology is suitable for room-level positioning and is highly accurate within defined zones.
• Ultra-Wideband (UWB): UWB technology involves tags continuously transmitting radio frequency (RF) energy. With the help of multiple receivers, UWB systems offer precise location data, often accurate within a few centimeters.
• Vision: Vision-based systems use cameras to monitor and recognize the locations of objects or people. High-quality cameras capture images or data, which are then sent to host computers or databases for tracking purposes.
• Wi-Fi: Wi-Fi-based RTLS leverages existing Wi-Fi infrastructure, where Wi-Fi tags or smart devices send signals to Wi-Fi access points. The data collected by these access points is used to calculate the location of tagged items.

Each of these technologies has its advantages and limitations, making it crucial for organizations to select the most appropriate technology based on their specific requirements and environmental factors.

Received Data & Granulation

To achieve accurate and granular location data, RTLS systems rely on various methods, including trilateration and the use of location indicators:

• Trilateration: Trilateration is a common method used to calculate positions based on the coordinates of three fixed points (receivers). By knowing the distances from each receiver to the target object, the system can narrow down the object’s location. Trilateration is often used in combination with multiple receivers capturing signals from a single tag.
• Multilateration: Multilateration is similar to trilateration but involves the use of more than three fixed points (receivers). The additional receivers further enhance the accuracy and granularity of location data.
• Location Indicators: Location indicators include measurements such as time, angle, or signal strength. These indicators provide additional data that helps improve the accuracy of location calculations.

Examples of location indicators and methods include:

• Time of Arrival (TOA): TOA calculates the elapsed time between a signal being sent and received, requiring synchronized clocks between tags and receivers.
• Time Distance of Arrival (TDOA): TDOA determines locations based on the time it takes for signals to reach multiple receivers.
• Time of Flight (TOF): TOF measures the time it takes for signals to travel from receivers to tags and back, often requiring precise timestamps.
• Angle of Arrival (AOA): AOA relies on the angles at which signals are received by multiple receivers with known positions.
• Received Signal Strength Indicator (RSSI): RSSI measures the strength of signals received by receivers, often used in RFID and related technologies.

By leveraging these methods and indicators, RTLS systems can provide detailed and accurate location data, enabling organizations to optimize their operations, improve security, and enhance asset management.