How to choose a locating technology — before you talk to a vendor.
Most people arrive at this decision having already been shown a demo. This page works the other way round: start from the job that has to get done, and let that narrow the technology. It takes about six minutes to read, and it will save you a procurement cycle.
Start with the job, not the radio
Every vendor in this market leads with one technology, because one technology is what they sell. That is not dishonest — it is what being a vendor means. But it produces a predictable failure: a system that performs exactly as specified and still does not answer the question the business asked.
The useful starting point is a sentence with no technology in it. “An engineer cannot find the spare part they were told we hold.” “We do not know a shipment is late until it fails to arrive.” “We write off tooling every year that is probably still on site.” Those three sentences have three different answers, and only one of them is about accuracy.
The five questions that decide it
In practice the choice collapses onto five constraints. Work through them in order — the first one that binds hard usually eliminates most of the field.
- How precisely do you need to know? Not how precisely would you like to. There is a large cost step between which building, which room, which aisle and which shelf. Most warehouse problems are solved at room or zone level.
- What is the environment made of? Steel racking, liquids, cold chain, outdoor yard and clean room each rule things in or out. Metal is the single biggest determinant, and it is why a tag that works on a cardboard carton fails on a tool.
- What is being tracked? A pallet, a returnable container, a hand tool and a person have different size, value, movement and privacy profiles. Item-level and pallet-level are different programmes with an order of magnitude between their tag counts.
- Does it need a battery? Passive tags last for years and cost cents. Active tags report continuously and need managing — replacement schedules, disposal, and someone whose job it is. That operational cost is routinely left out of business cases.
- Who consumes the data, and how fast? A nightly reconciliation into an ERP is a different system from a live map on a screen. Real-time is expensive and frequently unnecessary.
What each family is actually good at
Honest summaries, including when not to use each. Ranges are indicative; real performance depends on the survey.
| Technology | Answers | Strong when | Avoid when |
|---|---|---|---|
| Passive RAIN RFID | Did it pass this point? | High tag counts, no batteries, goods-in and dispatch, cycle counting | You need continuous position between read points |
| BLE | Which room or zone? | Large areas cheaply, long battery life, phones as readers | You need sub-metre precision |
| UWB | Exactly where, to 10–30 cm | Safety, collision avoidance, tool control, dense congested space | The job only needs the aisle — the infrastructure cost is real |
| GNSS / RTK | Where outdoors | Yards, fleets, plant, long-range logistics | Indoors, or under structure |
| LoRaWAN | Coarse position, plus condition | Very large sites, sparse assets, sensor data alongside location | You need frequent updates or fine granularity |
| Vision | What is it, and what condition? | Goods-in inspection, damage capture, identity without tagging | Line of sight cannot be guaranteed |
If you want the head-to-head detail, the independent technology comparisons go deeper — including UWB vs BLE for RTLS and UWB vs RFID.
Four ways people pick the wrong one
- Specifying accuracy you do not need. The most common and most expensive error. Ten centimetres sounds better than three metres in a meeting, and costs several times more to install and maintain.
- Believing datasheet read ranges. Published figures are free-space, single-asset numbers. Inside a loaded steel rack you will not see them. Only a survey in your building tells you the truth.
- Buying a system before fixing the data. If your asset register is wrong, a locating system will tell you precisely where the wrong thing is. Master data comes first.
- Letting the integration be an afterthought. The radios are rarely what fails. The interface into the ERP, WMS or maintenance system is where programmes slip, and it usually depends on a third party.
Hybrid is the normal answer
Treating this as a single choice is itself a mistake. A working estate often runs a portal read at the dock, room-level BLE through bulk storage, UWB in one high-value area and vision at goods-in — because those are four different questions on one floor. What makes that coherent is not the radios; it is one identity scheme and one integration layer underneath them. Get that right and you can change any individual technology later without re-platforming.
How to test the decision before you buy
Whatever the shortlist says, prove it in your own building before committing. A proof of technology on rented hardware, against read-rate and accuracy criteria agreed in writing beforehand, costs a fraction of a rollout and is the only evidence that transfers. Set the acceptance test first — number of assets, stacking pattern, pass speed, antenna count and power — so that any supplier’s number is comparable to any other’s. Our RF site survey checklist covers what to measure, and the RTLS cost guide sets out what the whole thing actually costs beyond the hardware.
Frequently asked questions
Which locating technology is most accurate?
UWB, typically 10–30 cm. But accuracy is only the right question when the job needs it. Most warehouse problems are solved at room or zone level, where BLE or passive RFID cost a fraction of UWB.
Do I need RFID or RTLS?
Passive RFID tells you an asset passed a read point. RTLS tells you where it is now. If the question is did it arrive, RFID is enough. If the question is where is it, you need RTLS. The RAIN RFID vs RTLS guide covers the boundary in detail.
Can I mix technologies?
Yes, and most working estates do. The integration layer matters more than the radios.
How do I test the decision before buying?
Run a proof of technology on rented hardware in your own building, against criteria agreed in writing beforehand. Datasheet ranges will not be achieved in a loaded rack.
Where to go next
If you want a starting point in ninety seconds, the technology picker asks four questions and names a direction. If you would rather talk it through, independent RTLS consulting and industrial RFID strategy explain how we work — we sell no hardware, no software and no licences, and we take no commission from any vendor, so the recommendation is not paying for itself. To put numbers against it first, use the ROI calculator.