Five Key Tag Technologies Powering Real‑Time Location Systems

Five Key Tag Technologies Powering Real‑Time Location Systems

Real‑time location systems (RTLS) combine three core elements: software, readers, and location tags. While GPS tags can transmit directly via cellular, most RTLS solutions rely on one of several tag technologies. Below, we explore the five most common tag types, their strengths, and typical deployment scenarios.

1. Ultra‑Wideband (UWB) Tags

UWB tags emit ultra‑short, wide‑band pulses that enable centimeter‑level accuracy. Readers detect the arrival time of these pulses, calculate precise distances, and relay the data to a central server. UWB is ideal for environments where pinpoint location matters, such as barcode scanners in warehouses or high‑density inventory systems.

Key considerations:

• Very low power signal—minimal interference with Wi‑Fi or cellular.
• Short operating range requires dense reader placement and meticulous calibration.
• High data throughput demands a stable, low‑jitter IP backbone.

Leading UWB Providers

• Redpoint Positioning
• DecaWave
• Zebra

2. Wi‑Fi Location Tags

Wi‑Fi tags operate at the network layer, broadcasting beacon frames that are captured by existing access points. Because they piggyback on routine Wi‑Fi traffic, they can achieve power efficiencies that allow months of battery life. Accuracy typically falls within one meter, improving when operating on the 5 GHz band with up to 80 MHz of bandwidth.

Advantages:

• Leverages pre‑existing Wi‑Fi infrastructure.
• Balanced trade‑off between coverage and precision.

Notable Wi‑Fi RTLS Solutions

• Versus
• AeroScout

3. Infrared (IR) Tags

Infrared RTLS uses light pulses transmitted from tags to ceiling‑mounted readers. The absence of radio waves eliminates wall penetration, providing unequivocal room‑level accuracy. However, deployment requires a dedicated IR network, often paired with Wi‑Fi or RFID to mitigate individual system limitations.

Infrared Systems

• Versus (Wi‑Fi + Infrared)

4. Passive RFID Tags

Passive RFID tags are inexpensive and consume no battery, but they demand high‑power readers and short read ranges. They are prevalent in airports, shipping, retail, and libraries. In medical settings, companies like KitCheck use passive tags within a high‑power reader enclosure to inventory pharmaceuticals quickly.

Passive RFID Vendors

• View Technologies

5. Active RFID Tags

Active RFID tags transmit their own radio signal, enabling broader coverage. Location is derived from signal strength or trilateration across multiple readers. Popular active tags include iBeacon BLE units, which are low cost ($2–$10) and non‑proprietary. Challenges include wall penetration and potential false positives, addressed by advanced filtering algorithms in systems like AirFinder.

Active RFID Providers

• AirFinder
• Visybl
• BluVision

Choosing the Right Tag Technology

When evaluating RTLS options, consider accuracy, range, power budget, infrastructure cost, and environmental constraints. Download our white paper to guide your selection and implementation strategy.