BLE Channel Sounding or UWB: Which Radio for Asset Tracking Tags?

What accuracy does an asset tracking product actually need?

Start from the workflow, not the radio. Asset tracking splits into three accuracy tiers, and each tier has a different hardware answer:

• Room or zone level, 3 to 5 m. Which ward holds the infusion pump, which dock door the pallet crossed. Plain BLE beacons with RSSI already do this.
• Bay or shelf level, 0.5 to 1 m. Which racking bay holds the tote. This is the tier Bluetooth 6.0 Channel Sounding targets.
• Bin, slot, or hand level, 10 to 30 cm. Which bin, which surgical kit, which forklift fork. This tier still belongs to UWB or camera fusion.

Most products over-specify. A hospital searching for pumps needs the right room, not the right shelf edge, and paying UWB tag prices for zone data burns margin. The reverse mistake is worse: promising slot-level accuracy on a 2.4 GHz phase measurement and discovering steel racking at pilot time. Buy the accuracy the workflow needs.

How does Bluetooth 6.0 Channel Sounding actually measure distance?

Channel Sounding, added in Bluetooth Core 6.0 in September 2024, gives BLE a real ranging mode instead of RSSI guesswork. It combines two measurements. Phase-based ranging hops across up to 72 channels in the 2.4 GHz band and measures carrier phase at each step. Round-trip timing measures time of flight and cross-checks the phase result, which also defeats simple relay attacks. The catch is physics: the whole 2.4 GHz ISM band spans about 83.5 MHz, and distance resolution scales with bandwidth. Silicon vendors show 10 to 30 cm in line-of-sight demos. In a building full of racking, forklifts, and people, multipath folds reflections into the phase estimate, and field results land closer to 0.5 to 1 m. The economics are the draw: Channel Sounding runs on single-chip SoCs like Nordic's nRF54 series, so a tag that already ships BLE gets ranging for near zero added BOM. The radio is nearly free. The physics is not.

Why does UWB keep the accuracy edge in cluttered buildings?

UWB ranges by timing nanosecond pulses across a 499.2 MHz channel, standardized in IEEE 802.15.4z and profiled by the FiRa Consortium. That bandwidth is the whole story. A 500 MHz channel resolves signal paths about 2 ns apart, roughly 60 cm of travel, so the receiver can pick the first arriving path, the direct one, and discard reflections off racking and concrete. Bluetooth's 83.5 MHz band cannot separate those paths. UWB is built to. The result in production systems is 10 to 30 cm typical two-way ranging error, with tuned installs reaching under 10 cm. That is why Apple has put UWB in every iPhone since the iPhone 11 and ships it in AirTag, and why forklift and tool-tracking RTLS vendors standardized on it years before Bluetooth 6.0 existed.

Datasheet accuracy claims are line-of-sight numbers. Multipath rejection is what survives contact with a warehouse.

Bandwidth is the moat.

What do the two radios cost in BOM, battery, and infrastructure?

Tag cost. A BLE Channel Sounding tag is one SoC, one antenna, one coin cell. A UWB tag adds a dedicated ranging IC, Qorvo DW3000 or NXP Trimension class, plus a second antenna and front end, typically a few dollars of extra BOM at volume. At 100,000 tags, that difference is a line item your CFO will read.

Battery. A BLE tag advertising once per second runs 3 to 5 years on a CR2032. UWB two-way ranging costs more energy per fix, so UWB tags survive on duty cycling: range on motion or on demand, sleep otherwise.

Infrastructure. BLE locators can piggyback on gateways you already deploy. UWB TDoA needs anchors with tight time sync and line of sight to tags, and every anchor needs power and often Ethernet. Anchor install, not tag price, is usually the largest cost in a UWB rollout. The tag is cheap. The ceiling is not.

Which radio should your product ship with in 2026?

Three rules cover most asset tracking products:

• Ship Channel Sounding when sub-meter is acceptable and you win on tag price, battery life, or BLE compatibility. Zone tracking, presence, loss prevention, and bay-level inventory all fit.
• Ship UWB when the workflow fails above 30 cm. Slot-level picking, tool crib control, surgical kit tracking, and anything feeding automation that acts on position.
• Ship both when precision is occasional. The AirTag pattern: BLE handles discovery and coarse location at microamp average current, then wakes the UWB radio for a precise fix. A dual-radio tag ranges precisely only in the seconds someone is searching, which protects the coin cell.

Also check your handsets. Every iPhone since 2019 carries a UWB chip, and Samsung and Google flagships ship UWB, while phone-side Channel Sounding support is only now arriving with Bluetooth 6.0 silicon. If workers locate assets with a phone in hand, UWB is the installed base today. Pick per workflow, not per datasheet.

You picked the radio. Who owns the positioning methods?

Radio choice is the easy half. The hard half is the positioning layer on top: how you schedule ranging exchanges, fuse RF with inertial or camera data, reject multipath, and turn raw ranges into positions a workflow can act on. That layer is where a decade of granted patents lives, and the standards bodies do not shield you from it. The Bluetooth SIG and IEEE license the protocol, not the system-level positioning techniques built on it.

Position Imaging holds hundreds of granted patents in RF ranging, real-time positioning, and vision fusion, including US 11,774,249, US 12,079,006, US 12,066,561, and US 12,000,947, and the portfolio is cited in filings by Apple and Bosch. Licensing does two things for a product team at once: it hands your engineers proven methods they do not have to reinvent, and it gives you freedom to operate before launch instead of a demand letter after. License the ranging IP. Spend your months on product.