How Accurate Is UWB in 3D?

We Tested Z-Axis Tracking With a Robot Dog

UWB works great on flat ground — but what about stairs? We strapped a UWB module to a robot dog and ran a real-world test.

Vertical Positioning Indoors: A Real Challenge

UWB (Ultra-Wideband) is one of the most promising technologies for precise indoor positioning. It’s already used in smart factories, logistics automation, robotics, and sports performance tracking.

But most UWB positioning tests focus on the X and Y axes — horizontal movement. So what about the Z-axis? Can UWB accurately track vertical movement?

At FREEGROW, we decided to find out. We equipped one of our in-development robot dogs with a UWB tag and sent it up and down stairs to test real-time 3D tracking.

Our Goal: Real-World 3D Positioning With UWB

The robot dog used in this experiment is part of FREEGROW’s ongoing R&D efforts. It’s being developed for industrial use — smart factories, patrol automation, and research platforms.

This Z-axis test had three key objectives:

• Validate the feasibility of 3D indoor tracking using a robot dog
• Observe how the Z-axis data changes when walking up and down stairs
• Evaluate the precision of real-time vertical positioning using UWB

Test Setup

To measure Z-axis data, we created a simple indoor test environment:

• Location: Office meeting room
• Anchor configuration: 4 UWB anchors
• Anchor placement: Mounted on the ceiling in a square formation
• Tracking mode: Real-time trilateration via ceiling-mounted anchors

The Result: Accurate Z-Axis Tracking in Real Time

As soon as the robot dog began to climb the stairs, the UWB tag started transmitting its coordinates in real time.

And the graph told the full story:

• The Z-axis graph rose gradually with each step upward
• At the top, it leveled off and remained steady
• As the robot came back down, the graph descended precisely

This clearly showed that UWB sensors can track vertical movement with high precision in indoor spaces — not just horizontal.

But… Can’t GPS Do This?

We often get this question:

“Can’t GPS handle indoor positioning?”

The answer: not really. GPS is designed for outdoor use and typically suffers from signal dropouts and 1–5 meters of error indoors.

UWB, by contrast, delivers centimeter-level accuracy, even in cluttered, signal-rich environments.

When it comes to precise indoor 3D tracking, UWB clearly outperforms GPS.

What We Confirmed

• With just 4 anchors, UWB can achieve accurate 3D indoor tracking
• Z-axis changes are reflected in real time
• Positioning error is within centimeters
• Applicable to robotics, drones, logistics automation, and smart factories

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Try It Yourself With FREEGROW’s UWB Dev Kit

GrowSpace UWB Creator Kit

With the GrowSpace Creator Kit, you can build your own real-time indoor tracking system — with just 3 anchors.

Ideal for:

• Robotics developers
• Smart factory & warehouse innovators
• Teams comparing UWB to GPS or BLE for indoor use

This plug-and-play kit includes everything you need to start testing. No proprietary software or complex infrastructure required.

See It in Action (Coming Soon)

We’ll be sharing the full test video soon. Watch the robot dog move step-by-step — and see the Z-axis graph react in real time.