BLE Locator · Beacon-Tag · Bluetooth 6.0 Channel Sounding

Bluetooth BLE Indoor Positioning (Locator / Beacon / Bluetooth 6.0)

Bluetooth positioning is P-Square's most cost-effective solution: tags are low power with roughly one year of battery life, hardware cost is low, and one Locator drives four read heads covering five points, cutting hardware volume to about a fifth and dramatically reducing cabling work. Four Bluetooth architectures are available, and P-Square is actively developing algorithms for Bluetooth 6.0 Channel Sounding (phase-based ranging). Deployed at a leading semiconductor manufacturer, healthcare providers, automotive plants (BMW, Audi) and construction sites.

Architecture 1: Bluetooth Locator Positioning

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Figure: Bluetooth Locator architecture — tags advertise, Locators scan, and the back end computes position with AI Fingerprinting.

Personnel, trolleys and assets carry BLE tags that advertise continuously; fixed Locators deployed across the site scan for them. Locators forward the signals over Ethernet to a switch (or through a plant private 5G network) to the positioning server, where the AI Fingerprinting algorithm computes position for display on the web platform.

The cost efficiency comes from the deployment model: one Locator unit can drive four extension read heads, covering five points in total. Compared with one unit per point, hardware volume falls to about a fifth and installation and cabling costs fall with it. Locators are compact and can be installed under raised flooring or inside suspended ceilings without affecting the appearance of the site.

Architecture 2: Bluetooth 6.0 Channel Sounding

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Figure: Bluetooth 6.0 Channel Sounding — phase difference replaces RSSI estimation for far more precise ranging.

Estimating distance from RSSI signal strength and then solving position by trilateration is readily disturbed by obstruction, human bodies and metal structures, so the error is large. P-Square’s mainstay AI Fingerprinting also reads RSSI, but never converts it into a distance — it matches the pattern of signals measured on site against a reference set built in advance, finding the position directly, so no distance-conversion error accumulates. In partitioned environments that is more than 30% more accurate than trilateration. The Channel Sounding introduced in Bluetooth 6.0 takes a third route, using PBR (Phase-Based Ranging): the Initiator and Reflector measure the phase difference across multiple channels to derive true range, breaking the RSSI limitation while retaining Bluetooth's low power draw and broad compatibility.

Ranging algorithms available under Bluetooth 6.0 include IFFT (inverse fast Fourier transform), Phase Slope, RTT (round trip time) and MUSIC (multiple signal classification). P-Square's core technology is an IFFT peak compensation algorithm based on PBR, validated on the Nordic nRF54L15-DK platform (Initiator / Reflector) with P-Square tags.

Four Bluetooth Positioning Architectures

Architecture	How it works	Best suited to
1. Locator-Tag	Tags advertise; fixed Locators scan and forward to the back end for computation. The Locator runs on an open platform (Raspberry Pi class), so it integrates flexibly: one unit extends over four 10 m USB cables to act as five sensing points, and it can be concealed above a suspended ceiling. Where a site already has Bluetooth tablets, those can serve as locators directly.	Personnel, trolley and asset tracking in plants, hospitals, automotive facilities and construction sites
2. Mobile smartphone positioning	The user's handset scans fixed beacons and computes its own position before reporting it.	Visitor wayfinding, mall navigation, wide-area personnel positioning without issuing badges
3. Beacon-Tag	Fixed beacons advertise continuously; a moving tag scans RSSI and re-advertises, and Locators receive it for AI Fingerprinting computation.	Sites where the tag must do the scanning; display via HDMI screen or a browser connected directly to the Locator
4. Bluetooth 6.0 Channel Sounding	Phase-based ranging replaces RSSI estimation for precise distance measurement.	Next-generation deployments: indoor positioning, asset tracking, smart wearables, safety monitoring

Bluetooth Hardware Specifications

Item	PTG_001 (label)	PTG_002 (wristband)	PTG_003 (label)
Bluetooth version	Bluetooth 5.0	Bluetooth 5.0	Bluetooth 5.0
Dimensions / weight	Φ39 × 15.5 mm, 50 g	Φ35.9 × 11 mm	38 × 38 × 9 mm
Antenna	PCB antenna	PCB antenna	PCB antenna
Advertising interval	100 ms – 5000 ms	100 ms – 5000 ms	100 ms – 5000 ms
TX power	-40 to +4 dBm (8 steps)	-40 to +4 dBm (8 steps)	-8 to +4 dBm
Battery / runtime	CR2477, about 1 year at 1 advertisement/second	CR2032, about 4 months	CR2032, about 3 months at 1 advertisement/second
Warranty	1 year	1 year	1 year

A BT-Dongle USB Bluetooth receiver is also available (22 × 16 × 6 mm, NCC CCAJ14LP4120T2). PTG_001 carries CE, FCC, RoHS, REACH approval.

Field Deployments

Construction site Locator system

Deployment scale at a single site for a major domestic construction contractor:

66 locating devices across 5 floors
5 gateways connected to the router over Ethernet
61 Locators relaying data over a mesh network
30 tags (BLE 4.0), six of which carry a g-sensor and duress button
Fire-resistant and waterproof housings; power adapters BSMI certified

Leading domestic semiconductor manufacturer: people and asset tracking

Locators were deployed over the plant’s existing network, with tags carried by staff and fitted to trolleys:

65 Locators covering the production area
Over 300 tags, on both people and assets
Used for people and asset tracking, cutting the time spent looking for staff and materials and improving day-to-day efficiency

Where It Is Used

Semiconductor and manufacturing: personnel duress, trolley and material container search, movement heat maps
Healthcare: medical equipment tracking, one-touch clinical duress, infection-control contact tracing
Automotive: personnel and asset tracking, as deployed for BMW and Audi
Construction sites: multi-floor personnel tracking, duress alerts, mesh backhaul
Long-term care: geofenced wandering prevention, fall reporting, wristband tags
Hotels, kindergartens and schools: trolley, asset and personnel tracking

Frequently Asked Questions

How long do Bluetooth tag batteries last?

At one advertisement per second, the PTG_001 label with a CR2477 cell lasts about a year and the PTG_002 wristband with a CR2032 about four months; the smaller PTG_003 lasts about three months. The advertising interval is adjustable between 100 ms and 5000 ms, so lengthening it extends runtime. Low-battery notification is supported.

What does one Locator driving four read heads actually save?

One Locator unit drives four extension read heads, covering five points in total. Compared with a full unit at every point, hardware volume falls to about a fifth and, more importantly, the amount of network cabling to be installed falls sharply — usually the dominant cost when retrofitting an existing building.

Does Bluetooth positioning lose accuracy in heavily partitioned buildings?

This is precisely where P-Square's core technology applies. Conventional trilateration degrades markedly as walls and obstacles increase; the AI Fingerprinting algorithm combined with structured map features improves accuracy by over 30% in partitioned environments, reliably determining which building, floor and room a person or asset is in.

Is Bluetooth 6.0 Channel Sounding available now?

P-Square is actively developing Channel Sounding algorithms, with an IFFT peak compensation algorithm based on PBR as the core technology, validated on the Nordic nRF54L15-DK platform. The value lies in replacing RSSI estimation with phase difference measurement, significantly improving ranging precision while retaining Bluetooth's low power draw and compatibility. Please contact the project team to discuss timing and applicability.

Deploy Bluetooth Positioning at a Sensible Cost

Contact the P-Square project team to assess Locator density and tag selection.

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