For a modular-office-partition client building a circular-economy model, we deployed Real-Time Location Services using two BLE technologies. Channel Sounding (Bluetooth 6.0) gives 10–30 cm distance for secure inventory; CTE-based Angle of Arrival (Bluetooth 5.1) gives sub-metre directional guidance across large spaces. Each component's tag ID links to the material metadata behind its EU Digital Product Passport.
As an engineer at Full Stack Energy, my focus is always on technologies that deliver tangible value — particularly for clients committed to sustainable practice. Our recent Real-Time Location Services (RTLS) work with a customer in the modular office-partition sector brought two advanced Bluetooth Low Energy positioning technologies into focus: Bluetooth Channel Sounding, and Angle of Arrival (AoA) using Constant Tone Extension (CTE). For this customer, a circular-economy model isn’t just corporate social responsibility — it’s a strategic necessity, increasingly shaped by the evolving EU regulatory landscape.
Why does the regulatory landscape drive this?
In the EU, the push for a circular economy is significantly impacting construction. A key development is the introduction of Digital Product Passports (DPPs) under the revised Construction Products Regulation. Soon mandatory for many products, DPPs carry vital data on a product’s origin, composition, and potential for reuse or recycling. The EU mandates the content and digital accessibility of these passports but not the underlying physical identification method. Our application associates the comprehensive material metadata — the backbone of the DPP — with each physical component via its unique BLE tag ID, making metadata-database tracking an essential tool for compliance and efficient lifecycle management.
Channel Sounding: precise distance for inventory
Bluetooth Channel Sounding, introduced in the Bluetooth Core Specification 6.0 (finalised September 2024), offers precise distance measurement. It exchanges carefully timed signals across multiple radio frequencies between two BLE devices; by analysing minute phase shifts (Phase-Based Ranging) and the exact round-trip time (RTT), we determine the distance. Crucially, RTT can verify the PBR measurement, giving a robust defence against signal spoofing or relay attacks — an important consideration when tracking valuable assets.
Its advantages for partition components: it can work with a single antenna per device (simpler tags) while supporting up to four for better accuracy; achieves 10–30 cm precision for prompt location of specific panels, doors or framing; combines PBR and RTT to mitigate location spoofing and protect material-passport integrity; helps organise storage layouts for efficient space use; is cost-effective and power-efficient to suit long-life circular products; and uses multipath-mitigation algorithms to stay reliable in the reflective RF environments of stripped-down buildings.
CTE-based AoA: directional guidance for logistics
Angle of Arrival, enabled by the Constant Tone Extension in Bluetooth Core Specification 5.1 (finalised January 2019), offers a different and equally valuable insight: directionality. A tagged component sends a standard BLE packet with a Constant Tone Extension; specialised locators with a multi-element panel antenna analyse the subtle phase differences as the signal arrives across the array to calculate the angle of origin. With multiple locators, you triangulate position.
AoA relies fundamentally on a receiver-side multi-element antenna array, while the transmitting tag stays single-antenna, simple and low-cost. It provides directional guidance (“which way to go” to find a stack of panels), sub-metre accuracy (0.1–0.5 m) suited to room- or bay-level location, efficient on-site redeployment to the right component, scalability across thousands of tags and multiple floors, and a clear real-time map to streamline deconstruction planning — all logged against each component’s DPP.
Channel Sounding answers “where exactly is it?” with spoof-proof precision. AoA answers “which direction do I go to find it?” Together they turn finding into being guided.
Our strategic approach
The optimal solution often integrates both. Channel Sounding suits detailed inventory, secure storage and precise tracking of individual higher-value items within a defined area. CTE-based AoA suits large-scale logistics, asset flow across broader spaces, and directional guidance for personnel in dynamic environments. Deployed selectively, these BLE technologies support circular-economy models for building components, refined logistics, warehouse optimisation, safety through people and asset tracking, and many other industrial use cases — enabling a more sustainable, efficient future driven by the rising need for material passports and comprehensive metadata.
Where this connects
This is the kind of problem where hardware, firmware and analytics have to be co-designed — exactly the philosophy behind our bespoke hardware design and our indoor positioning project. Knowing which technology fits is itself the discipline we describe in custom hardware isn’t hard — knowing when to build it is.