RTLS-nauwkeurigheid — wat de cijfers eigenlijk betekenen.

Realistische nauwkeurigheid per technologie onder productiebelasting.

UWB (TDoA, goed ontworpen): 10–30 cm @ 95e percentiel gecontroleerd; 30–60 cm in een typische industriële baai; degradeert tot 100+ cm als de ankerdichtheid verkeerd is.

BLE - AoA: 50 cm tot 2 m @ 95e percentiel, afhankelijk van de dichtheid van de Locator, antennegeometrie en plafondhoogte.

RAIN RFID (locatie-niveau): 1–3 m op itemniveau onder een plafond gefaseerde array; aanwezigheid bij portaalleespunten.

GPS / GNSS (standaard): 3–5 m buiten; Werkt niet binnenshuis.

GNSS-RTK: 1–3 cm buiten met correcties; vereist onbelemmerd uitzicht op de lucht.

LoRaWAN geolocatie: 100–500 m via TDoA over meerdere gateways; Goed voor aanwezigheid, niet positieprecies.

SLAM (visueel / lidar): 5–20 cm in in kaart gebrachte omgevingen; verslechtert sterk als de omgeving verandert.

Waarom claims over leveranciersnauwkeurigheid meestal in het 95e percentiel zitten onder laboratoriumomstandigheden.

De meeste specificatiebladnummers gaan uit van zichtlijn, ontworpen dichtheidsplaatsing, gekalibreerde montage, geen productiebelastinginterferentie, enkelvoudig toetsen.

Echte productieomgevingen verlagen die cijfers met 30–100%.

Vraag leveranciers om de nauwkeurigheid van het 95e percentiel te citeren onder jouw omgeving. Ze zullen zich verzetten; Dat verzet het antwoord is.

Hoe nauwkeurigheid achteruitgaat — de vijf veelvoorkomende oorzaken.

Multipath van metalen reken, glas, roestvrijstalen panelen, vloeren van betonaggregaten, HVAC-kanalen.

Ankerbevestigingshoogte-drift — 200 mm van het ontwerp verandert de UWB-dekkingsconus met 15–25%.

Synchronisatiedrift — TDoA vereist nanosecondensynchronisatie; een verkeerd bekabelde PoE-switch vernietigt de nauwkeurigheid stilletjes van streek.

RF-blokkers geïntroduceerd na de survey — racking, bewaking, mezzanines.

Productie-belastinginterferentie — Afsluiting van de heftruckmast, dokdeurcycli, perscycli.

How to specify accuracy so vendors cannot hide behind lab numbers

RTLS accuracy is meaningless without percentile, environment and use-case conditions. A vendor quoting “10 cm” usually means a best-case or median result in a clean lab. Operators should specify accuracy as: technology + percentile (50th and 95th) + environment class (open / partitioned / metal-heavy) + tag motion + update rate + whether first-path NLOS was present. That sentence is what belongs in RFPs and pilot gates.

Realistic production bands. UWB: often 10–30 cm when geometry is good; can stretch toward 0.5–1.5 m under industrial NLOS if anchors are poorly placed. BLE AoA: roughly 0.5–3 m depending on density and multipath; BLE RSSI alone is typically multi-metre zone-level. Wi-Fi RTT: often 1–5 m depending on AP density. Passive RFID portals: not continuous accuracy — they deliver presence at a read point with a read-rate KPI instead.

Match accuracy to the locating decision. Warehouse asset find: 1–3 m may be enough. Ward equipment: room-level. WIP station presence or OR table distinction: sub-metre. Forklift–pedestrian safety: centimetre-class with low false negatives. Paying for UWB everywhere to answer room-level questions is a common budget failure.

Why pilots look better than day 60. Empty bays, ideal tag mounts, low traffic and vendor-tuned filters inflate early numbers. Production load adds mast occlusion, moving metal, body shadowing and layout drift. Build acceptance tests for peak conditions and re-measure after the first layout change.

Contracting tip. SLAs that only guarantee accuracy under the installer’s commissioning conditions are weak. Tie acceptance to your operational KPI and percentile under agreed live-load scenarios, and keep a remediation path (retune density/orientation) before any automatic hardware uplift.

Reporting accuracy to boards and vendors without losing the plot

Report locating accuracy as distributions over time and zone classes. A single site-wide average hides the cell that fails safety thresholds and the ward that already meets room-level needs. Pair accuracy charts with operational KPIs so leadership sees whether centimetres (or metres) actually changed search time, dwell or utilisation.

When vendors present new firmware claims, re-run the same production-load script before accepting a contractual accuracy uplift. Firmware can help; it does not repeal multipath. Keep a living accuracy register per zone as part of managed operations — especially after layout changes.

For hybrid estates, never average UWB and BLE error into one number. Publish separate bands per radio layer so buyers and operators set expectations correctly.

Accuracy and latency are twin locating requirements

A precise fix that arrives too late cannot drive a safety interlock or a station confirmation. Specify latency alongside accuracy in every pilot gate. Some workflows tolerate multi-second BLE updates; others need sub-second UWB. Measuring only centimetres while ignoring time-to-event produces systems that look accurate in reports and fail in operations.