High-Performance Ranging (HPR)
Two-way ranging accuracy with little tag airtime
HPR is Noccela’s proprietary UWB positioning protocol, built on active-passive two-way ranging: a tag ranges with one base station while the other base stations in range listen in. That gives the accuracy and coverage of two-way ranging while keeping each tag’s airtime and energy use low, and it keeps a two-way radio link to every tag.
- Positioning accuracy (up to)
- 10 cm
- Coverage per base station (up to)
- 500 m²
- Active tags at 1 Hz within radio range
- 1,000
- Configurable update rate
- 0.1–50 Hz
Figures for Noccela systems using HPR. Capacity counts moving tags within radio range of a base station.
The trade-off HPR addresses
UWB positioning systems mostly use one of two methods. Each is good at something the other is not.
Two-way ranging (TWR)
The tag and a base station (UWB anchor) exchange messages, and the round-trip time gives the distance. With distances to three or more base stations, the position follows.
Strengths: accurate, wide coverage, no clock synchronisation between base stations, and the tag can receive.
Cost: several messages per base station for every position. With four base stations that is roughly an order of magnitude more transmissions than one blink, which limits tags per area and battery life.
Time difference of arrival (TDoA)
The tag sends one short blink. Base stations timestamp its arrival, and the differences between the timestamps give the position.
Strengths: one message per position, so tags last long and many fit in one area.
Cost: base stations must share a common clock to within a fraction of a nanosecond, because light travels about 30 cm per nanosecond. Accuracy drops outside the area the base stations enclose, and tags that only transmit need a side channel for configuration.
HPR
HPR keeps what ranging does well and cuts its airtime cost with active-passive two-way ranging (AP-TWR).
- Active-passive ranging: the tag exchanges messages with one base station, the active one. The other base stations in range listen passively and measure the same exchange, so one exchange serves all of them.
- Ranging-based: positions come from measured distances, so there is no timing network, and coverage is up to 500 m² per base station.
- Low airtime: a tag transmits once per position, not once per base station, so its airtime stays close to that of a blink.
- Two-way link: every tag can receive configuration, alerts and firmware.
- Thin base stations: the positioning logic runs in the engine, in the cloud or on-premise.
How active-passive two-way ranging works
One ranging exchange between a tag and a base station, measured by every base station that hears it.
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The tag polls
A tag that is moving wakes up and sends a short ranging poll. Tags at rest sleep and send nothing.
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One base station answers
One base station, the active one, replies and completes the two-way ranging exchange with the tag. The round-trip timing gives a distance that no clock synchronisation can disturb.
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The others listen
The other base stations within range are passive: they receive the same messages, record their own timestamps and transmit nothing. The tag has spent the airtime of one exchange, not one per base station.
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The engine computes the position
The positioning engine, in the cloud or on-premise, combines the active range with the passive measurements and the known base station positions, and streams the position to the platform and the APIs.
Because the active base station answers the tag, the link is two-way: the same exchange carries configuration, alerts and firmware to the tag. And because no base station needs a shared clock, each one needs only its PoE cable and calibrates its own position. How automatic calibration works
TWR, TDoA and HPR side by side
General characteristics of each method. Real systems vary with vendor, configuration and site.
| Property | Two-way ranging (TWR) | TDoA | Noccela HPR |
|---|---|---|---|
| How a position is made | The tag exchanges messages with each base station; distance comes from the round-trip time | The tag sends one short message (a blink); base stations compare its arrival times | Active-passive two-way ranging: the tag ranges with one base station and the other base stations in range listen in |
| Tag airtime per position | High: several messages per base station | Low: one blink | Low: one ranging exchange per position, however many base stations receive it |
| Base station clocks | No synchronisation needed | Must share a common time base to within a fraction of a nanosecond (cables or wireless) | No timing cables; one PoE cable per base station for data and power |
| Accuracy and coverage | High, also towards the edges of coverage | High inside the area enclosed by base stations; weaker outside it | Accuracy up to 10 cm; coverage up to 500 m² per base station |
| Tags per radio area | Limited by the airtime each tag uses | High | 1,000 active tags at 1 Hz within radio range; tags at rest do not use capacity |
| Tag battery life | Shorter: the tag transmits and listens more | Long | Typically several years, depending on utilisation and update rate |
| Link back to the tag | Yes | Usually not over UWB; configuration needs a side channel | Yes: configuration, alerts and over-the-air updates |
| Defined by | IEEE 802.15.4; FiRa Consortium; omlox | FiRa Consortium (downlink and uplink TDoA); omlox | Noccela (proprietary) |
Why the two-way link matters
Configuration
Change a tag’s update rate, sleep timeout or mode from the platform. A forklift tag can report often, a pallet tag rarely, and both can be changed later without touching the tag.
Alerts on the device
Make a tag buzz and flash when its wearer enters a zone, help someone find a tagged asset, or confirm on an Andon Button that a call was received.
Over-the-air updates
New tag firmware is delivered over UWB through the base stations, so improvements reach tags in the field without collecting them.
What HPR means for your use case
Assets in factories and warehouses
Workplace safety
Sports and animal tracking
Healthcare and care
Integrators and product builders
Tracking people? Define the purpose first, prefer safety-only modes and pseudonymised badges, keep retention short and consult employees before go-live. Privacy by design for people tracking
HPR and the standards
HPR is proprietary. It is Noccela’s own protocol, not a published standard, and it is not certified by a standards body. The radio it runs on follows the IEEE 802.15.4 UWB physical layer on channel 5.
The standards have moved on. The current base standard, IEEE 802.15.4-2024, includes the secure-ranging features first published as 802.15.4z. The FiRa Consortium added downlink TDoA to its core specification in 2023 and uplink TDoA, where infrastructure tracks tags, in 2025. omlox standardises two-way ranging, uplink and downlink TDoA, and an energy-saving two-way mode in which several anchors overhear a single tag exchange.
Active-passive ranging is not unique. Letting several anchors overhear one ranging exchange is an idea that other vendors and omlox pursue in their own ways. HPR is Noccela’s implementation, developed in our own products since 2017. What we publish about it is what it delivers in our products: the numbers on this page.
How to choose. If interoperability with third-party tags or smartphones is your first requirement, look for systems certified to an open standard. If you want accuracy, long tag life, a two-way link and a system that calibrates itself from one supplier, HPR is built for that.
Frequently asked questions
What is High-Performance Ranging (HPR)?
Is HPR two-way ranging (TWR) or TDoA?
Is HPR a standard?
Can third-party UWB tags or smartphones be used in an HPR network?
How many tags can an HPR system handle?
Does HPR need line of sight?
Test HPR on your own site
A pilot shows accuracy, coverage and battery life in your environment, with your assets and people, before you commit.