Logistics / Warehousing / Asset Tracking
UWB Asset Tracker: Ultra-Wideband RTLS with TDoA and Two-Way Ranging for Warehouses
For a Bangalore warehouse-technology company we built an ultra-wideband (UWB) RTLS with custom UWB modules, TDoA and two-way ranging, and WMS integration. Completed by early 2025; retrieval times fell ~60% (client-reported).
What we did: We designed custom UWB modules and their low-power RTOS firmware, implemented Time Difference of Arrival (TDoA) and Two-Way Ranging (TWR) localisation, added mesh networking for large sites and edge processing for low-latency updates, and integrated live positions with the client's warehouse management system (WMS).
Warehouse-technology company, Bangalore, India6 monthsTeam of 6
Published Last reviewed:
Illustrative imageThe Challenge
The client needed to track assets inside warehouses with high precision and without GPS, which does not work indoors. Positions had to update fast enough for dynamic warehouse operations, the system had to scale to large sites, feed the client's warehouse management system in real time, and be cheap enough to mass-produce in India.
GPS-denied environment
Inside a warehouse there is no usable GPS signal, so positioning must come from a local radio system.
Impact: Indoor RTLS requiredLow-latency positioning
Assets move constantly; stale positions are of little use to warehouse operations.
Impact: Real-time updatesScale
Large warehouses need many tags and anchors to work as one system without the network becoming the bottleneck.
Impact: Large deploymentsCost for mass production
The hardware had to be cost-optimised so it could be manufactured in volume in India.
Impact: Mass-production BOMOur Solution
We designed a UWB real-time location system (RTLS). UWB measures radio time of flight very precisely, so positions come from timing rather than signal strength. We used two methods: Two-Way Ranging (TWR), where a tag and an anchor exchange messages to measure the distance between them, and Time Difference of Arrival (TDoA), where fixed anchors timestamp one tag message and the position is solved from the differences. Mesh networking scales the system across large sites, and processing at the edge keeps updates fast and reduces dependence on the cloud.
System Architecture
UWB modules, a localisation engine, and a live feed into the WMS.
UWB hardware
- Custom-designed UWB modules
- Low-power firmware for extended tracker battery life
- RTOS-based firmware
Localisation
- Two-Way Ranging (TWR) for tag-to-anchor distance
- Time Difference of Arrival (TDoA) for position solving
- Edge processing for low-latency updates
Network and integration
- Mesh networking for large warehouse deployments
- API integration with the client's WMS
- Real-time analytics from live positions
Key Design Points
| Radio | Ultra-wideband (UWB) |
| Methods | TDoA + Two-Way Ranging |
| Firmware | RTOS, low-power |
| Network | Mesh, for large sites |
| Processing | At the edge, low latency |
| Integration | API to the client's WMS |
What We Delivered
- Custom UWB module design
- TDoA and TWR localisation algorithms
- Low-power RTOS firmware for trackers
- Mesh networking for scalable deployments
- Edge processing for low-latency position updates
- WMS API integration for real-time analytics
- Cost-optimised design for mass production
Outcome
The system completed field trials in warehouses and was integrated with the client's WMS. The client reported that misplacement and retrieval times fell by about 60%. We do not publish a positioning-accuracy figure: accuracy depends on anchor layout and site conditions, and no test protocol for it is on record.
How to read the labels: Measured by client = measured by the client's own team in operation.
Misplacement and retrieval time
Measured by client~60% lower
Reported by the client
Field trials
Completed
Real-time positioning in warehouse conditions
WMS integration
Live
Positions feed the client's warehouse management system
Design duration
6 months
Team of 6
Technologies Used
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