Expert article
Where exactly was that? Localisation on the construction site
Every piece of documentation stands or falls with the location. In the structural shell that is the hardest detail of all to give — because no GPS works there.
Expert article by Open Experience GmbH. As of: September 2026
What does automatic localisation mean on the construction site?
Automatic localisation means determining the position of a capture or a person within the building without anyone setting it manually on a plan. Because satellite navigation is unreliable inside reinforced concrete structures, other methods come into play: image recognition identifies building elements in the capture and matches them against the 3D model, supplemented by sensor data fusion. This was investigated in the BMBF project ESKIMO; in production, positions are placed today on the floor plan or in the model.
Legal framework: Germany (Civil Code BGB, construction contract rules VOB/B, fee schedule HOAI). Other countries have different rules, and contractual agreements take precedence over the standard periods named here.
Why the location is the weakest link
The time and the author of a capture come about by themselves. The place does not — and without it, even the best documentation cannot be used in a dispute.
- GPS ends at the facadeIn reinforced concrete structures satellite navigation is imprecise to unusable — precisely where the documentation is being made.
- Rooms look alikeIn the structural shell one storey barely differs from the next. Mix-ups are the rule, not the exception.
- No networkMethods that need a connection fail regularly on the construction site.
- It cannot be done after the eventWhatever was not located during the walkthrough can only be guessed at in the evening.
Methods compared
No single method solves the problem on its own. That is why practice combines them.
| Method | Strength | Limit |
|---|---|---|
| *By hand on the floor plan* | Robust, available immediately, no extra technology | Costs one action with every capture |
| *QR code on the element* | Unambiguous, inexpensive, offline | Presupposes prepared elements |
| *Satellite navigation* | Usable outdoors and on the ground floor | Unreliable indoors |
| *Image recognition with model matching* | No manual action, works indoors | Presupposes a model and computing power, research status |
For most projects the combination of floor plan placement and QR code is the most dependable solution today.
How model matching works
The approach from the ESKIMO project exploits the fact that an image contains more than its subject: if an algorithm recognises doors, windows, columns and openings in a 360° capture, their arrangement forms a signature. That signature is compared with the topology of the BIM model — if it fits in one place only, the position is determined. Sensor data from the helmet system supplements this.
- Recognising instead of measuringIt is not the distance that is determined but the match with known building elements.
- Robust hardware neededOrdinary smartphones deliver neither 360° captures nor the computing power for this — hence the helmet camera system.
- Runs offlineOn the construction site no method may presuppose an internet connection.
What works without automation today
Placing the position by hand is unspectacular and deals with the greater part of the problem. In the Open Experience apps the position is set on the 2D plan or on the element in the 3D viewer — with the coordinate and the camera position stored. 360° captures sit at their capture point in the floor plan. That makes the defect, the photograph and the walkthrough findable, years later too.
The effort does not lie in setting the point, but in doing it the first time round instead of during rework at the office.
Locations that help nobody later
"Ground floor, back left"
In six months that is no longer a location but a riddle.
"As discussed"
The reference lives in the heads of two people — and in no document.
The image file name
IMG_4711.jpg contains no location, however firmly everyone assumes the opposite.
The wrong storey
The most common mix-up in the structural shell — and barely resolvable after the event.
Yesterday's plan
A position on a superseded floor plan points nowhere.
Better
A point in the current plan or the element in the model — set at the moment you are standing in front of it.
The state of play — viewed soberly
The methods developed in the ESKIMO project are proven and promising, but they are prototypes. For everyday work that means: automation takes the locating off nobody's hands, but the technology does take the trouble out of it. Anyone who places positions consistently in the plan today will have tomorrow the data on which automation becomes possible at all — and until then, documentation that can be found.
Frequently asked questions
Does GPS work on the construction site?
Outdoors and on the ground floor usually yes, inside multi-storey reinforced concrete structures as a rule not accurately enough. For locating individual building elements it is not sufficient there.
Do I need a BIM model in order to place positions?
No. The floor plan is enough. With a model the placement becomes three-dimensional and thereby more precise — and it is the precondition for automatic matching.
How does placing a position work without an internet connection?
Plan and model are held on the mobile device, the position is stored locally and synchronised later. Offline capability is not an added feature on the construction site but a basic condition.
What is the benefit of the QR code on the element?
It supplies the unambiguous assignment without any searching: scanning opens the right checklist or the right element reference. Particularly effective with recurring elements.
Is automatic localisation available today?
Not as a product function. It was trialled in the ESKIMO project. What is in production is manual placement in 2D and 3D — which already delivers the greater part of the practical benefit.
Does this capture movement data about employees?
Locating captures is something other than tracking people. Where employees would be affected, data protection and co-determination apply — that has to be settled before deployment, not afterwards.
Sources and legal basis
The legal statements in this article are based on the primary sources listed below. The article is not a substitute for legal advice in an individual case.
A location that is still correct in five years.
45 minutes on your project: placing positions in the floor plan, in the model and by QR code — and which of them will carry you fastest.