GPS alone is too inaccurate for AR. So we fused it.

The result: 3D content that sticks to real places and gets more precise the longer the user walks. One URL, no app, fully offline.

Walk around your content — WebXR anchors hold, nothing floats
Any ordinary QR code = door + instant position fix
Real 6DoF in the browser: Android + Chrome today

// the code — a GPS anchor in ~5 lines

// the whole flow — gps-plus-slam-app-framework
const store = createSlamAppStore({ storageBackend: new NullStorageBackend() });
await initAR(container);         // one tap → 6DoF AR in the browser
const world = getArWorldGroup()!;
world.add(marker);               // marker: any three.js Object3D
createGpsAnchor({ object3D: marker, arWorldGroup: world, camera: getCamera()!,
  gpsPoint: { lat: 48.137, lon: 11.575 },  // ← your real-world spot
  getAlignmentMatrix: () => selectAlignmentMatrix(store.getState()),
  getGpsZeroRef: () => selectZeroReference(store.getState()) });

Scroll to walk in ↓ Jump to the demos →

Any ordinary QR code does two jobs.

One scan jumps straight into AR, no install — and pins the user to the exact spot they're standing on, before GPS has even warmed up.

Raw GPS scatters by meters. Fusion holds still.

Every GPS reading is an uncertainty circle around a different center. Averaging them nails the spot — and fusion with WebXR tracking keeps it nailed while the user moves.

This is what your users see.

Their own phone — or any WebXR-capable device — becomes the window. No download: arrows, labels and stories laid over the real world.

Works anywhere. Fully offline.

No cloud mapping, no scanning vans, no pre-scanned city centers — and no cloud positioning service that can be priced up or sunset. If the user can stand there, a story can live there. Dream up the real-world AR experience you always wanted to build: a forest with a magic portal that only opens at dawn, a plaza your users capture in 3D to take home, a park with your jump-and-run parkour.

What will you build?

Anything that needs precise global positioning, runs offline, and places 3D content in the physical world:

Guided tours & city walks with content at the real spots
Campus, venue & trade-fair navigation
Architecture previews & historic buildings at 1:1 scale
Make the invisible visible: what's hidden behind walls or long gone, shown on site
Reality capture: GPS-anchored 3D scans & Gaussian splats
Safety training & emergency drills on location

The code is on GitHub.

The demos below run on Android phones with Chrome — same engine, same repo. No signup — everything you need comes included. Clone it, run it, bring your favorite place to life.

Fork & start building

Or try the live demos

Anchor Starter Demo Place a GPS anchor, generate a link to it, and when the link is loaded it re-places the anchor at the exact same physical spot. QR-Tracking Demo Point at any printed QR code: it measures the code's real size from the depth map and glues a 3D axis + cube to it. Physics Demo Drop physics balls that bounce off the reconstructed real-world mesh: replay a recorded walk on the desktop and watch them settle on the captured surfaces. Minimal Example App Tap to place anchors with one part floating in GPS space and one part fixed in AR space — showing the regular alignment drift. Recorder App Record and replay user sessions from a real phone. Use them to simulate user behavior while developing, or view the captured content — images, point clouds, even reconstructed Gaussian splats.

Common questions

Which devices are supported?

Android phones support full 6-DoF tracking on Chrome today — that's why the framework currently works there and not on iOS. It targets standard WebXR, so any headset that fully supports that standard (including 6-DoF SLAM tracking) will work as well.

How accurate is the positioning?

Raw GPS is meters off; fusion averages it down. Try the demo apps to see whether it works for your use case — and use QR codes for extremely accurate, instant anchoring.

What's the license?

Does it need a server or an internet connection?

No. The GPS+WebXR alignment runs entirely on the device — there is no cloud positioning service involved. The page and content are static files you can host anywhere.

How do I start building?

Clone the repo and run the demo apps to learn the basics. The Minimal Example App is a good starting point, and the Recorder App is the most complex example — you can also use it to record realistic user input for your test-driven development.

GitHub repository Documentation npm: gps-plus-slam-app-framework