AR construction preventing construction errors: A new standard for safety and quality

Table of contents

• Benefits of overlaying drawings with AR

• Preventing construction mistakes by visualizing boundary lines with AR

• Safely excavating by displaying underground utilities with AR

• Improving efficiency of layout marking and surveying using AR

• Challenges of AR implementation: accuracy and alignment

• Achieving "non-shifting AR display" with high-precision positioning

• Simple surveying and AR utilization starting with LRTK

• FAQ

Benefits of overlaying drawings with AR

On construction sites, mistakes are often discovered after construction due to misreading drawings or insufficient sharing of the intended image, leading to rework. For example, overlooking a small positional shift on a plan can result in a completed structure being off the property boundary by a few centimeters (a few in), or misinterpreting the indicated drainage slope can lead to rainwater not flowing properly in the finished work. Such cases are not uncommon. Behind these troubles lie issues such as the difficulty of grasping the final form from two-dimensional drawings alone and the designer’s intent not being fully shared among everyone on site.

Augmented reality (AR) technology is attracting attention as a new means to fill these gaps and improve construction quality. Because you can overlay design drawings or 3D models onto the real landscape through a smartphone or tablet camera, you can intuitively confirm the finished form on site. From site supervisors to tradespeople to clients, everyone can view the same AR image and share “what and how things will be built,” preventing mistakes due to mismatched perceptions. Displaying drawing data in AR on site before construction offers the following main benefits:

• Visualizing the final image: The appearance after completion, which was hard to imagine from paper drawings or cross-sections alone, can be experienced realistically by overlaying it on the actual scenery. Because the placement and height relationships of buildings and structures can be grasped at a glance, the designer’s intent can be accurately shared among everyone on site.

• Preventing construction mistakes: By overlaying the design model and the current landscape in AR and checking them, you can notice misalignments or interferences during construction on the spot. For example, if you check the formwork position in AR before concrete placement, you can detect and correct positional deviations of a few centimeters (a few in) in advance. Early detection and correction of errors significantly reduce the risk of rework.

• Facilitating consensus-building and improving client satisfaction: Using AR for explanations to clients or other departments makes it easy to share the completed image that is difficult to convey with paper drawings. It prevents misunderstandings such as “it’s not what I expected,” and enables concrete feedback at the proposal stage. Because the finished appearance can be reconciled and agreed upon in advance, it also contributes to higher satisfaction after handover.

• Improving efficiency of layout marking and surveying: Overlaying drawings with AR brings innovation to position-setting (layout marking) on site. Because you can display design reference lines and positions on the ground in AR while marking, stake location setting that once required experienced surveyors can be performed accurately by anyone. As a result, work time can be shortened and surveying/verification can proceed efficiently even at sites with a labor shortage.

Preventing construction mistakes by visualizing boundary lines with AR

On construction sites, accurately understanding site and building boundary lines is extremely important. If a building is shifted from the planned position and crosses the boundary due to a slight misunderstanding, it can lead to disputes with neighbors or be deemed an illegal building. Traditionally, boundary confirmation relied on survey maps and on-site boundary markers (stakes/plates) and visual judgment, but fitting lines on the drawing to the site mentally required experience and risked overlooking a positional error of a few centimeters (a few in).

With AR, you can visualize the boundary lines and building layout lines shown in the design drawings directly on site. If you preload site boundary data into a smartphone or tablet AR app, virtual boundary lines will appear on the bare ground. By comparing actual boundary markers with the AR lines, you can intuitively grasp positional deviations of a few centimeters (a few in) that are hard to detect by eye. Also, because exterior wall and structure placement lines can be shown on the ground in AR, you can confirm before foundation work whether the “designated building position” maintains appropriate clearance from the boundary. Such prechecks prevent errors of being too far or too close to the boundary, reducing the risk of rework later.

Moreover, AR display of boundary lines is useful for explanations to neighboring residents and for building consensus. The site extent and setback positions, which are difficult to convey with paper drawings alone, become obvious when visualized with AR. Explanations like “the boundary runs from here to here, and we will install the fence along this line” can be shown overlaid on the actual scenery, making it easier to obtain understanding from the surrounding community. As a result, troubles arising from misunderstandings about boundaries can be prevented in advance, allowing construction to proceed safely and smoothly.

Safely excavating by displaying underground utilities with AR

Buried items under the ground such as water and sewage pipes and power/communication cables are major risk factors during construction. Accidentally damaging existing infrastructure can delay the schedule, affect local lifelines, reduce safety, and lead to serious accidents. Because buried utilities are not directly visible from the surface, workers had to rely on as-built drawings and other materials to infer their positions and dig carefully.

Visualizing underground utilities with AR solves these problems. If you preload pipe and cable location information (drawing data or survey data) into an AR app, simply pointing a smartphone at the site will display the underground piping as if you were seeing through the ground. Like using an X-ray on the earth, you can immediately see what pipes are buried where, greatly reducing anxiety when deciding excavation locations.

For example, if there is information that “a water/sewer pipe runs at a depth of 1 m (3.3 ft) from here,” the pipe model can be displayed in AR at the 1 m (3.3 ft) depth beneath the ground. Workers can check the pipe’s routing through the screen as they excavate, and if they get close to an existing pipe they can immediately detect it and take evasive action. Displaying buried utilities with AR reduces the risk of accidentally damaging pipes, improving safety and construction efficiency. In supervisory or inspection settings, visual explanations of underground structures also smooth information sharing among stakeholders.

Improving efficiency of layout marking and surveying using AR

AR technology brings innovation not only to drawing checks but also to on-site measurement tasks such as layout marking and as-built surveying. Traditionally, tasks like staking positions or confirming structure heights required experienced surveyors to carefully use transits and levels. But with AR, anyone can intuitively confirm positions and dimensions according to the design.

For example, overlaying a rebar placement drawing in AR during reinforcement work allows you to check on the spot whether the number and spacing of rebar match the drawings. If there is a deviation, it can be noticed and corrected immediately, preventing reinforcement errors that might otherwise be discovered later. For road or site elevation checks, projecting the design’s finished elevation line into the space with AR and comparing it with the current embankment or excavation finish allows detection on the spot of errors such as “it looks flat but is actually a few centimeters (a few in) higher (or lower),” making it easier to judge whether compaction is insufficient or too much excavation occurred.

AR is also powerful for layout marking. Because reference lines and column centerlines (grid lines) based on design drawings can be displayed directly on floors or ground in AR, the labor of using tape measures or ink lines is greatly reduced. For example, projecting points indicating column positions or reference lines on the floor in AR and then marking along those markers enables accurate position setting. High-precision layout marking at a simple surveying level (簡易測量) can be achieved without relying on the intuition and experience of skilled workers, allowing young or small teams to work efficiently.

Challenges of AR implementation: accuracy and alignment

Although AR is convenient, to be truly useful on site it must overcome challenges of accuracy and alignment. Typical AR apps that run on ordinary smartphones or tablets can display models that are offset by tens of centimeters to several meters due to errors in the device’s GPS and various sensors. Indoors, the camera can correct position using wall and floor features, but wide outdoor civil and construction sites have few reference features, so display position errors and model scale drift are likely to occur.

Furthermore, overlaying drawing data onto the site coordinate system requires alignment between the model coordinates in virtual space and the actual survey coordinates. Many AR apps handle this by placing markers (QR codes, etc.) on site and reading them with the camera or by manually aligning the model to known points on site. However, these methods are time-consuming and can leave room for marker placement errors or human alignment error.

To achieve the accuracy required by construction sites—namely precision on the order of a few centimeters (a few in)—special measures are necessary. Especially when using AR over large sites, a positional error of several meters would make the overlayed drawings meaningless and impractical. To make AR a reliable tool on site, it is necessary to combine centimeter-level high-precision positioning (cm level accuracy (half-inch accuracy)) with low-effort coordinate alignment methods.

Achieving "non-shifting AR display" with high-precision positioning

A promising approach is combining high-precision positioning technology with AR to realize a “non-shifting AR display.” A representative example is RTK-GNSS (real-time kinematic GNSS), which reduces GPS positioning errors to within a few centimeters by adding correction information to satellite positioning. While a normal smartphone’s built-in GPS has errors on the order of meters, RTK-GNSS can achieve accuracy suitable for civil and construction site management.

LRTK is a solution developed to make RTK-GNSS easy to use on site. By attaching a dedicated compact antenna to a smartphone or tablet and receiving correction data from a base station via the Internet, you can continuously measure your position with centimeter-level accuracy. Feeding this high-precision self-positioning information into an AR app enables automatic and accurate alignment between design data and the real world.

The biggest advantage of introducing high-precision positioning is that it eliminates the cumbersome alignment work on site. Traditionally, it was necessary to set up surveying instruments at reference points on the drawing and carry out processes like driving stakes, but with LRTK simply standing at the location with a smartphone completes this. Design models are projected precisely to their designated positions based on world geodetic coordinates, so initial alignment adjustments are almost eliminated.

Moreover, centimeter-level positioning with LRTK dramatically improves the stability of AR displays. Even when walking around a wide site, models do not float or shift in the field of view and remain fixed in the correct positions. While regular AR can experience gradual drift as you move, high-precision GNSS corrections act as the “AR eye,” maintaining accurate positions. This enables reliable AR use for large-scale surveys spanning multiple locations or extensive as-built inspections.

High-precision positioning also contributes to vertical alignment. Because RTK-GNSS can precisely measure elevation, the height reference of models displayed in AR can also be accurately matched. Whether showing the depth of buried utilities in AR or verifying embankment heights in earthworks, the displayed vertical position matches measured values, increasing trustworthiness.

Simple surveying and AR utilization starting with LRTK

To fully utilize AR on construction sites, two keys are required: high-precision positioning technology and digitized design data. LRTK provides a simple platform that realizes both, strongly supporting on-site DX (digital transformation). With just an antenna attached to a smartphone, you can handle cloud sharing of drawing data, high-precision position corrections, on-site checks via AR display, and even point cloud measurement in a single workflow.

For example, upload design drawings (CAD data or BIM models) to the LRTK cloud and start the smartphone app on site to immediately display and confirm the drawings in AR. No complex equipment setup or special skills are required, and intuitive operation allows you to start simple surveying. Marking stake locations can be done by following the app’s guides, allowing even newcomers to perform accurately. By combining with LiDAR scanners built into recent smartphones and tablets, you can quickly capture 3D point cloud data of construction areas and use it for as-built checks and earthwork quantity calculations.

By using LRTK in this way, on-site surveying and verification work that used to depend on specialist surveyors can be performed easily by anyone. Visualizing drawings, boundaries, and buried utilities with AR helps prevent construction mistakes, while simple surveying enables high levels of efficiency and accuracy in site management. If you feel challenges in pre-construction position checks or mistake prevention, consider updating your site workflows with an AR solution that uses LRTK. The use of AR technology is becoming a new standard for preventing construction mistakes and for safety and quality management.

FAQ

Q: Do I need special equipment or expensive devices to use AR? A: No. Modern smartphones and tablets can basically utilize AR technology. You can start simply by installing a compatible app on a handheld device without dedicated AR glasses. If you require high accuracy in earnest, combining a compact GNSS antenna (for example: an LRTK antenna) to improve positioning accuracy will enable more reliable AR displays.

Q: Is smartphone GPS alone sufficient for AR drawing display? A: For simple checks, a smartphone’s built-in GPS can be used. However, its accuracy is limited to the meter level. To obtain the precision required for construction, a system that corrects positions to the centimeter level, such as RTK-GNSS, is needed. With ordinary GPS, discrepancies can occur between the drawing’s building positions and actual positions, causing walls and other elements to be off by tens of centimeters (tens of in). For important position checks, we recommend combining AR with high-precision positioning.

Q: How should drawing data for AR display be prepared? A: First prepare digital design files or models (CAD data, BIM models, or even image files). While 3D data is ideal, 2D drawings can also be displayed in AR by pasting them on the ground or converting lines. Using LRTK’s cloud service, you can upload your drawing files and easily call them up on site to overlay them in AR.

Q: Is AR adoption progressing in the construction industry? A: Yes. With policies such as “i-Construction” promoted by the Ministry of Land, Infrastructure, Transport and Tourism, the use of AR and 3D data is rapidly expanding. Not only major general contractors but also small and medium-sized construction sites are increasingly adopting tablet-based drawing sharing and AR for construction checks. Against a backdrop of increasing young technicians and labor shortages, AR as an easy-to-use digital tool is contributing to site improvements.

Q: Is it okay to skip traditional surveying and rely solely on AR for position verification? A: AR is fundamentally an auxiliary tool, and final inspections and critical reference setting should still be confirmed with traditional surveying instruments such as total stations. However, AR is very effective for in-progress checks and simple alignment. By continuously monitoring deviations between design and construction with AR and combining conventional surveying at key points, you can prevent mistakes while maintaining a balance between efficiency and quality.

Q: What are the costs and effort to introduce AR on site? A: The barrier to AR introduction is not as high as you might think. You can leverage existing devices such as smartphones and tablets, and many AR apps are low-cost or free. Even when adding high-precision positioning, small GNSS antennas (like LRTK ones) are more affordable than total stations and do not require special licenses. Initial preparation involves digitizing design data and uploading it, but once the workflow is established, on-site operation is simple. Considering the costs of traditional surveying equipment and rework, the benefits of AR are likely to justify the investment. You can begin with pilot implementation on small projects or specific phases and scale up as you gain familiarity. As drawing digitization progresses, the effectiveness of AR increases, and industry-wide promotion of BIM/CIM will further support adoption.