If you've ever tried tracking objects indoors with conventional GPS, you know it falls short due to satellite signals struggling to penetrate walls, steel, and glass. For accurate indoor localisation, Ultra-Wideband (UWB) technology is the game-changer, delivering centimetre-level precision. This project reveals how to build a DIY indoor UWB positioning system using the powerful Qorvo DWM3000 UWB module paired with ESP32 microcontrollers, enabling real-time location tracking with up to 10cm accuracy.
Why Ultra-Wideband for Indoor Positioning?
Unlike GPS, which relies on satellites 20,000 km away, UWB uses ultra-short radio pulses sent between devices to measure time-of-flight with nanosecond precision. This allows it to deliver sub-meter accuracy indoors where Wi-Fi and Bluetooth fall short. The DWM3000 module complies with the IEEE 802.15.4z standard and supports advanced ranging techniques that filter out multipath interference common in indoor environments, ensuring reliable positioning even in cluttered rooms.
Core Components
- Qorvo DWM3000 UWB Module: The heart of the system, this compact transceiver module integrates antenna, crystal oscillator, and power management, designed specifically for precise ranging.
- ESP32 Board: Handles communication with the DWM3000 via SPI and streams real-time position data over Wi-Fi.
- Anchors and Tags: Anchors are placed at fixed, known points, while the tag is attached to the moving object to be tracked.
How it Works: From Ranging to Real-Time Positioning
Anchor Setup: Place at least three anchors in fixed, known coordinates in your indoor space.
- Tag Initialisation: The ESP32-equipped tag initiates communication with anchors.
- Two-Way Ranging (TWR): Through a double-sided exchange of precise timestamped messages, the tag calculates the distance to each anchor.
- Distance Calculation: The DWM3000 converts time-of-flight measurements into distances with corrections for antenna delay.
- Trilateration: A Python script receives distance data over Wi-Fi, calculates the tag's (x,y) position by finding the intersecting point from the distances to the anchors using least squares optimisation.
- Real-Time Visualisation: The calculated position is plotted continuously on a floor plan, enabling live indoor tracking.
Innovations and Tips for Accurate Tracking
The system leverages double-sided two-way ranging (DS-TWR) to cancel out clock drift errors between devices, an essential step for achieving centimetre precision. The firmware also implements median filtering to reduce noisy measurements and monitors signal strength to detect and compensate for non-line-of-sight (NLOS) conditions.
Antenna delay calibration is critical—each module’s internal delay is measured and compensated to ensure exact timing. For most setups with the DWM3000, a delay setting of 16350 device ticks works well.
Applications
This UWB positioning system excels in many indoor environments:
- Warehouse robotics and asset tracking
- Hospital equipment and patient location monitoring
- Factory tool tracking and safety zones
- Retail analytics and customer flow measurement
- Sports player movement tracking
- VR/AR interactive experiences
Ready to Build?
The project includes complete firmware for both tags and anchors, along with a Python visualisation script. The seamless integration of hardware, firmware, and software enables a scalable system ready to grow from small indoor environments to complex real-time location systems (RTLS) with multiple tags.
By combining the cutting-edge Qorvo DWM3000 UWB technology with easy-to-use ESP32 microcontrollers, you can unlock precise indoor location tracking that once required expensive, proprietary solutions. Dive into this DIY project to bring real-time, centimetre-level indoor positioning to your own workspace or product.
For full source code, circuit diagrams, and detailed setup instructions, check out the official project UWB Indoor Positioning System using ESP32.
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