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RTLS and RFID: Perspective on two complementary systems

TLDR: RTLS and RFID are location-based systems (LBS) with each having strengths that make them a fit for specific use cases, but they can also be combined to enhance the location fidelity, building trust in the system and enhancing its capabilities.

The Details:

RTLS and RFID are often compared as if they are competing technolgies. They are both location-based systems, but they are different, meaning they function differently in our operational digital twin.

These technologies are part of the backbone of the system's spatial awareness. Each technology has its own unique capabilities, strengths and limitations. They can function separately but when combined they offer many automation opportunities.

Let's define each of these systems

• RTLS: Real Time Locator Systems, a system of distributed sensors that compute the location of battery powered tags that are fixed to something that is being tracked.
• RFID: Radio Frequency Identification, a system of distributed exciters that send RF energy into spaces where small RFID tags harvest the energy and use it to reply back with their identification code.

Let compare and contrast each of these technologies

RTLS

• Tags require batteries (Active)
• Tags are large compared to RFID
• Tags are higher cost than RFID
• Active tags are located by a system of sensors
• Sensors are lower cost than RFID
• Sensors are longer range than RFID

RFID

• Tags do not require batteries (Passive)
• Tags are small compared to RTLS
• Tags are lower cost than RTLS
• Passive tags are located by a system of exciters
• Exciters are higher cost than RTLS sensors
• Exciters are shorter range that RTLS

Limitations and Application:

Like any technology there are limitations so design becomes critical when applying these technologies to a solution. Below are some of the challenges of each technology and where they are applied.

RTLS - "Geographic Ubiquity"

• Because RTLS tags cost more, the focus is on high dollar and high value equipment and people tracking.
• Because of the longer range, all of the building can be covered (geographic ubiquity).
• Good fit for employee duress, patient wandering, finding equipment

RFID - "Item Ubiquity"

• Because the RFID tags are smaller and cost less the focus is on tags as many items as possible (item ubiquity).
• Because the range is limited (but precise), choke points and points of building egress is covered.
• Good fit for loss prevention, PAR stocking, supplies, infant protection

Hybrid RTLS and RFID

• Put RFID tags on as many pieces of equipment as possible
• Put RFID tags and RTLS tags on high dollar, high value equipment
• Enhance existing use cases like loss prevention, equipment stocking, finding equipment
• Use hand scanners for finding hoarded equipment (hidden) or any time RTLS is not performing as expected
• Use RFID and hand scanners for finding RTLS tags with dead batteries
• Create workflow automation for mobile workflows that do courier services like lab samples, medications, gasses, supplies and even patients

Key Takeaways:

Having a strategy around location-based services is critical. If you have both RTLS and RFID, don't look at replacing one or the other without looking at how a hybrid approach could be a part of your strategy. Some hospitals have older systems and vendors are pushing them to upgrade, but perhaps keeping the older system and adding a newer complementary system is a better approach.

Future: Location-based services are at a point in their evolution where they exist as discrete systems, but you can expect they will enter a phase where these technologies will merge. By combining the strengths and deprecating the weaknesses, a much more capable system will emerge.

You can stay updated on advancements in positioning systems by following Why Where Matters.

Until next week,

Paul E Zieske ​Location Based Services Consulting ​​​