The physical conditions shaping the result
Ultra-wideband (UWB) is a radio technology that transmits very short, low-power pulses across a wide frequency spectrum. Unlike Bluetooth beacons, which estimate distance by measuring signal strength (RSSI), UWB systems typically calculate position using time-of-flight (ToF) — the time a pulse takes to travel between a tag and fixed anchors. Because radio waves travel at a known speed, measuring that time interval yields a distance reading that is far less susceptible to the multipath and absorption problems that degrade RSSI-based systems.
In a controlled environment with clear line of sight and properly calibrated anchors, UWB can reliably achieve accuracy in the range of ten to thirty centimetres. That figure is not a guarantee: it depends on anchor geometry, the number of anchors in range, the presence of metal structures, and the quality of the on-site calibration. Any supplier quoting a single accuracy number without qualifying the test conditions is not giving you a complete picture.
A UWB indoor navigation installation consists of fixed anchors mounted at known positions, mobile tags carried by people or attached to equipment, and a positioning engine that computes coordinates from the measured ranges. For consumer-facing wayfinding — visitors navigating a museum or conference venue — the "tag" is typically the visitor's smartphone, provided it contains a UWB chipset. Support has grown in recent years, with UWB now present in a range of flagship smartphones, but it is not yet universal. For staff or asset tracking, dedicated UWB badges or tags are used instead.
It is worth understanding where UWB sits relative to other indoor positioning methods. Wi-Fi-based systems, covered in a neighbouring article, rely on existing infrastructure but typically deliver metre-level accuracy. Bluetooth beacons are inexpensive and widely supported but face similar RSSI limitations. UWB trades higher hardware cost and more complex installation for substantially better precision where that precision is genuinely needed.
Measure across devices and operating conditions
Where UWB justifies the investment
UWB makes most sense in environments where the operational cost of imprecision outweighs the capital outlay. A warehouse where pickers need to locate a specific bin to within a few centimetres, or a manufacturing floor tracking work-in-progress through tightly spaced stations, are typical examples. In healthcare, some hospitals use UWB to track high-value mobile equipment and monitor staff movement in restricted zones. These are cases where knowing "somewhere near that shelf" is not sufficient.
For visitor-facing indoor navigation in retail, museums and events, the calculus is different. Most wayfinding tasks — finding a particular gallery, a toilet, or an exhibition hall — do not require sub-metre precision. Standard Bluetooth or Wi-Fi positioning, combined with clear zone-based logic, often meets the need at lower cost. UWB becomes relevant in visitor settings only when the use case demands fine-grained location, such as guiding a visually impaired visitor along a precise path or triggering content at a very specific exhibit point without bleed from adjacent displays.
Anchor placement and calibration
UWB anchors need clear line of sight to the tags they are measuring. Metal racking, reinforced concrete columns, and even dense crowds can obstruct or reflect pulses, degrading accuracy. During planning, a site survey should identify these obstructions and determine anchor positions that provide overlapping coverage across the operational area. A minimum of three anchors is required for two-dimensional positioning; four or more improve robustness and enable three-dimensional tracking.
Calibration involves measuring the exact coordinates of each anchor — typically using a total station or high-accuracy surveying tool — and feeding those into the positioning engine. Some systems also apply environmental corrections to account for fixed reflectors or known signal paths. This is not a one-time task: any physical change to the space — new racking, moved partitions, altered ceiling grids — necessitates a review of anchor positions and potentially a recalibration.
Power and infrastructure
Fixed anchors usually require mains power, though some battery-powered options exist for temporary deployments. PoE (Power over Ethernet) is common, as it also provides the data connection back to the positioning server. Cabling runs are a real cost and logistics consideration, particularly in heritage buildings or leased spaces where drilling and trunking are restricted. For temporary event setups, the cabling requirement alone can make UWB impractical compared to battery-powered Bluetooth beacons that simply adhesive-mount to surfaces.
What changes invalidate the result
Assuming consumer devices will deliver full accuracy
A smartphone with a UWB chip does not behave identically to a dedicated industrial tag. Phone antennas are optimised for general connectivity, not precise ranging. The phone's orientation, whether it is in a pocket or held in hand, and the operating system's restrictions on background UWB scanning all affect real-world performance. If your business case depends on consistent sub-thirty-centimetre accuracy from visitor phones, validate that assumption with a pilot before committing to a full deployment.
Underestimating installation complexity
UWB is sometimes presented as "install the anchors and it works." In practice, achieving the quoted accuracy requires careful surveying, cable routing, network configuration, and iterative tuning. Expect the installation phase to involve multiple site visits, signal testing at representative points, and adjustment of anchor positions or engine parameters. Factor this professional services cost into the project budget rather than treating it as a minor add-on.
Ignoring maintenance overhead
Like any physical infrastructure, UWB anchors can fail, be displaced, or suffer cable damage. The positioning engine needs monitoring for degraded accuracy, and anchor firmware requires periodic updates. If the system is safety-critical — for example, controlling access to a hazardous zone — you need defined procedures for fault detection, fallback behaviour, and repair turnaround times. An asset register for anchors, comparable to the beacon inventory practices used in BLE deployments, is essential for keeping track of hardware locations, firmware versions and service history.
Privacy and consent
UWB tracking of staff or visitors generates location data that falls under UK data protection law. Even if the system uses anonymous identifiers rather than personal details, the combination of precise movement patterns and timestamps can be identifying in certain contexts. You need a clear lawful basis for processing, transparent privacy notices explaining what is tracked and why, and defined retention periods. For visitor-facing deployments, opt-in consent should be the default unless you have a compelling and separately justified reason for passive tracking. The same data minimisation principles that apply to Bluetooth and Wi-Fi analytics apply here, with the added sensitivity that UWB's precision makes the data more granular.
Questions to put to a UWB supplier
- What accuracy did you achieve in a deployment with similar building materials and layout, and how was it measured?
- What is the minimum number of anchors in line of sight required for your stated accuracy?
- How does the system handle tags that lose sight of all anchors — for example, in a lift or enclosed room?
- What happens to positioning accuracy when the space is crowded with people?
- What is the process for adding, moving or removing anchors after the initial installation?
- How does the positioning engine integrate with our existing wayfinding application or CMS?
- What ongoing monitoring and maintenance does the system require, and what alerts are provided for anchor failures?
UWB is a powerful tool for indoor navigation where precision genuinely matters, but it is not a universal upgrade path from Bluetooth or Wi-Fi positioning. The decision should follow from a specific operational requirement that cheaper technologies cannot meet, validated through a measured pilot in the actual environment, with a realistic budget that covers installation, calibration and ongoing maintenance — not just the cost of the anchors and tags.
