UWB anchor placement — the independent design guide.
Anchor placement is the difference between a UWB pilot that holds 30 cm accuracy and one that misses the KPI by 60 weeks of contractor billing. Here is what an independent RF engineer checks across Sewio, Ubisense, Pozyx, Kinexon, Inpixon and any UWB ecosystem.
How vendors over-specify anchor count — and how to spot it.
Vendor reference designs default to 1 anchor per 80–120 m² for production-grade UWB. We have audited Tier-1 automotive sites where 40 anchors hit the same KPI as the vendor 80-anchor design — 50% saving on hardware AND install (€33,000+ per site).
Three structural pressures push density up: SLA buffer, unfalsifiability lock-in, and hardware revenue. All three work against the buyer.
The fix: ask the vendor to model 70% of their proposed anchor count against your KPI. If they refuse, that is the entire answer.
The five anchor-placement rules that actually matter.
1. Ceiling-height verified, not nominal. An anchor designed for 4.2 m mounted at 3.8 m changes coverage cone by 15–25%. Every mount point gets measured.
2. Geometric offset for multipath, not ceiling grid. Metal racking, glass and concrete-aggregate floors create multipath. Placement compensates via geometric offset.
3. Multi-time-of-day survey passes. A 09:00 survey does not see the 14:00 shift cycle. We run minimum three passes.
4. TDoA synchronisation tolerance budgeted into network design. A mis-cabled PoE switch quietly destroys positioning without logging an error.
5. Acceptance test under production load. Vendor commissioning at 06:00 in an empty bay is a different RF environment from 14:00 on a busy shift.
What the audit deliverable looks like.
For a 5,000 m² site, an independent audit produces: predictive RF model against the as-built environment,
device count justification with KPI sensitivity at 70/100/130% of vendor density, mount-point register, multi-time-of-day data, network design with TDoA timing tolerance, acceptance test plan.
Typical fee: €8,000–€18,000 per site. Typical install-bill saving: €20,000–€50,000 single site; €100,000–€400,000 on 5–15 site rollouts. See our infrastructure and install service.
Frequently asked questions
How many UWB anchors do I actually need per square metre?
Vendor reference designs typically specify 1 anchor per 80–120 m². Independent audits routinely show 1 per 150–180 m² hits the same KPI — 30–50% reduction.
Does this guide apply to all UWB vendors?
All of them. The physics of UWB anchor placement is vendor-neutral. Differences between Sewio, Ubisense, Pozyx, Kinexon, Inpixon are reference-design assumptions and SLA architecture, not RF physics.
Can we self-audit without hiring an independent consultant?
If you have an in-house RF engineer with UWB experience, yes. If you do not, the cost of getting it wrong (€33k+ per site) exceeds the audit fee (€8–18k).
What is the most common anchor-placement mistake?
Mounting on the ceiling grid for speed instead of using multipath-tolerant geometric offset. This accounts for most post-install accuracy regressions.
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