What is RTLS
Last scan tells you where something was. A real-time location system (RTLS) reports where tagged people, vehicles, tools, or materials are while they still move, at the accuracy the next floor action needs.
What RTLS means on the floor
ISO/IEC 24730 describes RTLS as a wireless system that locates an item in a defined space at a time that is real time or close to it. On a plant floor that means a live wing, aisle, bay, or coordinate updating often enough that logistics can send a driver to the right place instead of starting a search. It is not the bin typed at putaway. It is not the station a scanner last saw. Plants use it for asset tracking and forklift tracking that must stay true during the shift, not only at the next checkpoint.
It is also not outdoor GPS reused indoors. Satellite signals drop under steel roofs and dense racking. Indoor RTLS uses radios, gate readers, or sensors on the vehicle itself to place the asset on a hall map people already know. Vendors often call that indoor layer an indoor positioning system. RTLS is the plant name for the same job when the output has to drive a live decision, not a one-off survey.
What last-scan systems do not tell you
Most floors already record location in pieces. A barcode at the dock says the pallet entered. A WMS putaway writes a bin. A MES complete says the job left Station 4. An ERP transfer says the stock moved to a storage location. Those are events. They are true at the moment someone scanned or confirmed. They go stale the second a forklift takes a detour, parks in a buffer, or drops the cage one aisle over because the assigned face was blocked.
That is why empty walks survive in plants that already own warehouse software. An ID on a pallet is not a live location. WIP cages drift. Returnable stillages sit behind a line that is not theirs. A vehicle reported as en route can still be waiting at a shared aisle. RTLS does not replace those systems. It fills the minutes between their events so the map matches the hall and inventory management decisions stop depending on the last successful scan alone.
Tags, anchors, and a live map
A working RTLS has three parts the floor can point at. Tags or beacons announce who they are. Fixed anchors, locators, gateways, or readers sit at known spots in the hall. A location engine turns that radio picture into a position, then a map places the location where operators already look: north buffer, dock 2, Line 3 inbound. On BLE, either side can move. Fixed gateways can track beacons on assets, or battery beacons can sit still while a gateway on the forklift calculates its own place. Without the map, you have a table of coordinates. With the map, a supervisor sees the same hall the driver is standing in.
The radio is not one product. Technology options include Bluetooth Low Energy (BLE), RFID, ultra-wideband (UWB), vehicle SLAM, Wi-Fi, yard GPS, and related builds surveyed under RTLS technologies out there. BLE commonly serves medium-precision location around 1–3 m (3–10 ft) for aisle and bay work, including both fixed-gateway layouts and gateway-on-truck layouts for powered vehicles such as forklifts and automated guided vehicles (AGVs). RFID splits into gate presence, proximity reads, and ceiling arrays that report a live X, Y, and Z, often around 1 m (~3 ft). UWB and SLAM commonly serve exact floor position when the mark itself matters. Wi-Fi can fill a large area when the plant already has access points and does not need a tight location. Yards still use GPS because the sky is open. One hall can mix those options on one map. The comparison layer sits under compare RTLS technologies.
What the plant does with the location is the second half of the system. A live position can stop a search, feed a no-go zone rule, rebuild a spaghetti diagram, or show dwell in a blocked buffer. None of that happens if the team only stores coordinates in a historian nobody opens during the shift.
Location accuracy is the decision that matters
Accuracy is not a brochure number you maximize. It is how wrong the location can be before the next action fails. Zone presence only needs to know the asset is in this wing of the building, often on the order of about 2,000 m² (~21,500 ft²), or that it passed a chokepoint. Medium-precision search needs the aisle or buffer: a 1–3 m (3–10 ft) reading is enough to kill a multi-minute walk, and for most plant logistics jobs that band is already precise. The last meters (last few yards) are still covered on foot. Exact floor position at sub-meter (~3 ft) starts to matter when "near the line" is not the same as on the mark. Many no-go zones already work at medium precision. A gate RFID read at a dock door is the presence job. Ceiling-antenna RFID RTLS draws a continuous path, often around 1 m (~3 ft), when the plant already prefers RFID tags. The accuracy split for logistics track is under zone presence vs medium-precision logistics track.
Indoor GPS is the trap in a lot of first meetings. It works in the yard. Under a metal roof it does not. Buying a tighter radio than the decision needs also has a cost: more anchors, shorter tag batteries, denser calibration. Start with the floor question under start with the decision, not the technology. Metal racking, moving forklifts, and concrete walls bounce radio. Treat published ranges as what a maintained industrial install usually holds, then walk a short aisle on your floor before you grow the grid.
How plant teams choose a system
1. Name the question this quarter will enforce - If the question is which aisle holds the last pallet of that SKU, medium-precision location around 1–3 m (3–10 ft) is the honest start. If you only need to know the asset is still in this wing, zone presence or a chokepoint read is enough. If the question is exact floor position on a mark, the mark tolerance sets the accuracy band you must buy. Do not buy sub-meter (~3 ft) hardware for a search problem, and do not ask a medium-precision layout to certify a centimetre (inch) floor mark.
2. Separate presence from path - Dock confirmation, shipping-door control, and cage hand-off often need checkpoint RFID or a reader at a known point. Continuous forklift paths, empty-round analysis, and live search need a stream that updates while the vehicle moves. That stream can be BLE, UWB, SLAM, or ceiling-antenna RFID RTLS. A gate or a proximity read is a different RFID price point and does not draw that path. Mixing a presence job into a continuous-path purchase, or the other way around, is how plants overpay for gates they could have scanned, or under-instrument halls they expected to map.
3. Put the location on a hall people already trust - Coordinates in a table still force a translation step. The operational picture logistics and production will actually use is a live digital twin, the same layer described under types of digital twins. If the map does not match the columns and doors on the floor, the RTLS project becomes another screen nobody opens.
4. Own the tags like you own radios - Batteries, mounting, and lost badges are part of the system. A cheap tag that dies every quarter will quietly turn the map into last week's guess. Match update rate to the decision: search can ping slower than a safety zone.
Once the position sits on a live twin
This is where twinzo sits after the concept is clear. The product job is not a second location vendor. It is the live hall view that can ingest BLE, UWB, RFID, SLAM, or the systems you already run, then place those locations next to material state and production signals. Live logistics uses that picture for internal logistics optimization and for industrial fleet management that the dock already owns. The same stream builds a spatially oriented dataset, the stored place-and-time record under the map that later models need. Correlation and causality analytics then read that record for hall-wide patterns and root causes, on equal footing with the shift search job. Supervisors use the same model for production monitoring when a line is waiting on a load that left the dock late. Capability detail lives on the features overview. A longer primer on radio mix lives in getting started with RTLS.
The concept to lock first is simpler than the stack. RTLS answers where the tagged thing is now, at the accuracy the next action needs, on a map the shift already understands. Buy that. Then let the twin carry the location into live logistics, the stored place-and-time record, and the pattern work that continuous improvement already owns.
Get in touch if you want to walk the same location question on your own facility model.