Table of Contents

• New possibilities AR technology brings to construction management

• AR use cases in construction management - Pile-driving guidance (streamlining stake-out with AR) - As-built verification (immediate confirmation of construction results with AR) - AR visualization of boundary lines (displaying invisible boundaries on site) - AR verification of design data (on-site model comparison and validation) - Comparison and validation with point cloud data (utilizing 3D scan data)

• Benefits of adopting AR

• What is LRTK’s latest AR technology?

• Simple surveying with LRTK

• FAQ

In recent years, the use of AR (augmented reality) technology on construction and civil engineering sites has advanced, drawing attention to efforts that overlay 3D design models and construction information onto real-world views via smartphones and tablets. By superimposing virtual objects onto site conditions, progress and final appearance can be intuitively visualized, yielding many benefits such as reducing construction errors, streamlining quality checks, and promoting information sharing between clients and the site.

However, conventional smartphone AR often suffers from positioning errors of several meters (several ft), making it inadequate for construction management and surveying tasks that require centimeter-level precision (cm level accuracy (half-inch accuracy)). This is why combining AR with satellite positioning using the RTK (Real-Time Kinematic) method has attracted attention. By using RTK technology, which applies real-time corrections to satellite positioning errors, smartphone AR positioning errors can be reduced to a few centimeters (a few inches), enabling high-precision AR displays.

Such “RTK-enabled AR” technology is expected to become a new solution supporting DX (digital transformation) in the construction industry. Amid the Ministry of Land, Infrastructure, Transport and Tourism–led *i-Construction* initiative and the trend toward ICT in construction, RTK-enabled AR is increasingly seen as a promising tool for enhancing and streamlining field operations. This article explains the transformative changes AR brings to construction management and describes concrete use cases, then concludes with an introduction to LRTK’s latest AR solution.

New possibilities AR technology brings to construction management

AR is beginning to transform construction management tasks that previously required mentally matching drawings to the field. Because digital design information can be overlaid on the actual site and checked on the spot, management based on data rather than experience or intuition has become possible. Layout tasks and as-built checks that tended to rely on veteran skills can be performed accurately by anyone with AR guidance. AR helps detect surveying and construction errors early and reduces rework. There are reported cases where displaying design drawings in AR on site enabled immediate correction of construction defects, preventing later rework and material waste.

AR can also address labor shortages and the challenge of transferring skills in construction management. From major general contractors to small local construction companies, heavy equipment operators and site supervisors are beginning to use AR. For example, in earthworks, an operator can project the design’s finished terrain model through a tablet and work while verifying excavation and fill heights. In foundation work, a supervisor can display foundation layout positions in AR, enabling accurate installation of structures even without experienced personnel. In these ways, AR raises on-site work quality and efficiency, and its potential to improve construction management is very large.

AR use cases in construction management

Let’s look in order at the main examples of how AR is being used in construction management.

Pile-driving guidance (streamlining stake-out with AR)

To place piles that form a structure’s foundation at exact positions, a pre-construction stake-out based on coordinates in the drawings is essential. Traditionally, stake-out work has been performed by survey teams using total stations or tape measures to measure distances from reference points and install marks or batter boards on the ground. Manual stake-out requires high-level skilled labor and consumes considerable time and effort. Surveying itself can be difficult depending on terrain and weather, and small errors can lead to later construction mistakes.

RTK-enabled AR can dramatically streamline these stake-out tasks. Through a smartphone or tablet screen, virtual piles or markers (AR markers) can be displayed at the positions specified in the design drawings, so workers can simply move toward the markers overlaid on the real scene to identify the target points. The screen shows real-time arrows and distance information, guiding users to the target pile like a construction-site GPS. As you approach the correct position, fine distances such as “about ○ cm (○ in)” are displayed, and when the virtual pile aligns exactly with a real-world mark, positioning is confirmed. Even inexperienced staff can intuitively determine accurate pile positions, enabling stake-out in a short time without relying on veteran intuition.

At sites that have introduced RTK AR, time required for pile-position marking has been greatly reduced compared to traditional methods; tasks that once took several people half a day have been completed quickly by one person in some reported cases. This leads directly to reduced manpower and cost; being able to position with centimeter accuracy (cm level accuracy (half-inch accuracy)) means almost no rework in subsequent processes. Also, workers can verify pile positions from a safe distance via the screen in hazardous heavy-equipment zones or on poor footing, improving safety. On concrete pavement where physical stakes cannot be placed or on steep slopes, AR display still enables accurate stake-out.

As-built verification (immediate confirmation of construction results with AR)

In civil engineering, as-built verification—checking that completed structures and regraded land match design shape and dimensions—is crucial. Traditionally, surveyors measured heights and positions in detail after work completion, then compared the returned data to drawings in the office to confirm quality. This process took time and required effort to organize and analyze measurement data.

With AR, much of as-built verification can be done in real time on site. For example, the design finished model or reference height lines can be displayed in AR over the actual object, allowing direct comparison with the constructed structure. In road embankment work, projecting the design finished line onto the ground and adding fill until that line disappears provides intuitive AR guidance to achieve the design form. After finishing, you can overlay the completed terrain with the design model on the smartphone camera view to inspect for slight hollows or shortages without overlooking them. Errors of a few centimeters (a few inches) that were previously easy to miss become instantly identifiable with AR, allowing immediate orders for additional cutting or filling.

Moreover, systems like LRTK can immediately acquire high-precision 3D point cloud data on site via the smartphone’s built-in LiDAR scanner or photogrammetry and compare it to design data. Because acquired point clouds have geographic coordinates, volume differences and cross-section deviations can be automatically calculated in the cloud. Even for complex terrain, detailed analysis such as “which part needs to be cut or filled by how many centimeters (how many inches)?” can be obtained in a short time, dramatically improving the accuracy and speed of as-built verification. Measurement data can also be used directly to create drawings and reports for inspections, resulting in major efficiency gains.

AR visualization of boundary lines (displaying invisible boundaries on site)

Accurately understanding property boundaries and construction extents is important for surveyors and construction managers. But boundaries are often shown only on drawings and are invisible on site. Existing boundary posts or markers can be hard to find when hidden by grass or terrain, and in some cases boundary points are not clearly marked at all. Confirming and sharing boundaries can therefore be time-consuming and carries the risk of disputes from misidentification.

RTK-enabled AR can visualize map boundary lines directly on site. If you register land boundary coordinate data in advance, simply pointing a smartphone camera on site will render the specified boundary line clearly in space. Even on vacant land, the screen will show boundary lines that would normally be invisible, so you can immediately understand “where the property starts and ends.” With RTK’s centimeter-level accuracy (cm level accuracy (half-inch accuracy)), boundary lines based on cadastral maps or design drawings can be displayed at their true positions, eliminating discrepancies in field recognition.

This AR boundary display is useful in many situations such as land surveying, land acquisition site visits, and pre-construction checks of work extent. For example, when planning road widening, it is difficult to convey the image of property boundaries to local residents with paper drawings alone, but projecting boundary lines and planned road widths on site using AR allows anyone to intuitively understand the situation. As a result, consensus building with residents becomes smoother. During construction, heavy equipment operators can refer to AR work-area lines to prevent unnecessary excavation or encroachment. Visualizing the “invisible information” of boundary lines thus greatly contributes to more efficient boundary confirmation and trouble prevention.

AR verification of design data (on-site model comparison and validation)

One goal of using design data (3D CAD or BIM/CIM models) on construction sites is to eliminate discrepancies between design and construction. AR verification of design models refers to overlaying a 3D design model onto the real scene on site to directly compare it with structures under construction or already completed. Because RTK-enabled AR ensures accurate alignment between the model and reality, you can immediately check on site, “Is this being built according to the design?”

For example, in bridge construction, displaying guides for bolt or column positions on the smartphone AR screen can prevent misalignment during component installation. For rebar placement or pipe routing, projecting the finished 3D model in AR lets workers continuously compare the model and the real object to ensure accurate installation. If positions or heights are off by even a few centimeters (a few inches), discrepancies between the model and reality become obvious on the spot. While RTK AR does not provide millimeter-level precision, it offers sufficient accuracy for on-site decisions in construction management.

Such AR verification enables early detection of construction errors and prevents rework. Deviations that were traditionally discovered only by post-completion surveying can be detected and corrected during construction with AR, reducing waste such as removing and reinstalling components later. If the client or the site supervisor checks AR footage together, mistakes from differing interpretations can be avoided. Sharing a digital “as-built” view among all stakeholders allows data-driven construction management without relying on veterans’ intuition. Before work begins, AR can also project finished models on site to check for clashes between structures or to preview the final appearance—practices that support on-site consensus building and quality assurance.

Comparison and validation with point cloud data (utilizing 3D scan data)

Recently, 3D point cloud data obtained from drones or laser scanners has begun to be used in construction management. A point cloud is a collection of countless measured points that digitally represent the shape of terrain or structures in detail. Using RTK-enabled AR, these point clouds can be displayed on site in AR and compared by overlaying them with design models or the actual scene.

For example, after an operator finishes excavation and filling in earthworks, they can scan the site with the smartphone’s LiDAR to obtain point cloud data. Because RTK assigns absolute coordinates to that point cloud, it can be treated in the exact same coordinate system as the design ground model. Displaying the design model and the acquired point cloud simultaneously on a tablet in AR will make overfilled protrusions or still-insufficient areas immediately apparent as shape mismatches or color differences. The major advantage is that you can intuitively check as-built conditions on site rather than comparing point clouds and design data back in the office.

You can also apply this to periodic inspections of existing structures by overlaying point clouds acquired at different times in AR to observe changes over time. Complex point cloud data is normally analyzed with specialized software, but AR overlays let you grasp differences from the perspective of the field. While detailed analysis and earthwork calculations can be done in the cloud using the acquired point clouds, AR display serves as a complementary, intuitive confirmation method. Point cloud comparison with RTK AR is a powerful tool for quickly finding discrepancies between design and reality and further enhancing the accuracy of quality control and as-built verification.

Benefits of adopting AR

• Improved surveying accuracy: Using centimeter-class high-precision GNSS (cm level accuracy (half-inch accuracy)) dramatically increases the reliability of position information displayed in AR. You can stake out boundary lines and structure positions on drawings without error, enabling detailed construction management that was previously difficult. Tasks are performed accurately based on data rather than relying on veteran workers’ intuition.

• Operational efficiency and labor savings: Time required for surveying, stake-out, and as-built verification can be greatly reduced. Following AR guidance allows workers to take the shortest route, making it possible for one person to perform what previously required several people. For example, pile-position stake-out that once took several people half a day may be completed quickly by one person, leading to significant efficiency gains, personnel cost reduction, and shorter schedules.

• Enhanced safety: AR reduces the need for workers to enter hazardous areas. As mentioned earlier, stake-out inside heavy equipment operating zones becomes unnecessary because positions can be guided from a safe distance. Completing surveying and verification quickly also reduces work during bad weather or at night, contributing to safety management.

• Smoother communication and consensus building: Digital information can be shared intuitively on site, improving communication among stakeholders. Presenting the finished image or boundary lines to clients, site staff, and local residents via AR provides a “seeing is believing” effect. Spatial images that are hard to convey on drawings can be shared on site, preventing rework and complaints from misunderstandings.

• Data utilization and promotion of on-site DX: Introducing RTK-enabled AR greatly advances field digitization. Positioning data, point clouds, and photo records are centrally managed in the cloud, reducing post-site data processing. Accumulated data can be used for analysis and reporting linked with BIM/CIM models, driving DX across operations. Using 3D data on site in ways that comply with *i-Construction* requirements also aligns with future public works standards and helps strengthen corporate competitiveness.

What is LRTK’s latest AR technology?

Finally, as a practical solution for easily introducing RTK-enabled AR on site, we introduce LRTK. LRTK is an all-in-one field DX tool that enables high-precision positioning and AR display using a single smartphone. By attaching a dedicated ultra-compact RTK-GNSS receiver (palm-sized) to a smartphone and launching the supported app, an ordinary smartphone instantly becomes a surveying device with centimeter accuracy (cm level accuracy (half-inch accuracy)). There is no need for complicated initial calibration or marker setup—just power on and high-precision AR is ready to use.

With LRTK, design coordinates and survey data can be uploaded to the cloud in advance and synchronized with field devices. For example, if you register a coordinate list of pile-driving positions, selecting it on site starts AR navigation and anyone can execute the virtual pile display and coordinate guidance described above. Similarly, importing linear data from drawings enables AR display of boundary or planned lines, and uploading point cloud data allows immediate on-site comparisons with existing conditions. These operations are provided via an intuitive UI so that non-specialist surveyors can also operate the system.

By using LRTK, which completes surveying and AR visualization with a single smartphone, field operations can proceed on a one-device-per-person basis. Tasks that previously required separate equipment and software—surveying, stake-out, as-built scanning, photo records, design verification—can be integrated on a single platform with LRTK, achieving dramatic efficiency gains. Sites that have introduced LRTK report feedback such as “Young employees could perform surveying and pile-driving without problems” and “Real-time cloud recording made reporting much easier.” The ease of adoption without expensive specialized equipment is also attractive, making LRTK accessible to small contractors and local governments that were previously distant from ICT construction.

To fully realize the potential of RTK-enabled AR, selecting tools that are easy to use on site is key. LRTK is an example that offers a practical solution balancing simple surveying and high-precision AR display. If you are considering introducing RTK AR, consider LRTK as an option to experience next-generation smart construction.

Simple surveying with LRTK

LRTK’s simple surveying revolutionizes traditional surveying tasks. With only a smartphone and a small GNSS device, anyone can handle centimeter-level positioning (cm level accuracy (half-inch accuracy)), dramatically improving on-site surveying accuracy and operational efficiency. Without relying on specialized personnel or expensive equipment, one device per person lets users perform coordinate measurement, pile-driving guidance, and as-built verification—enabling advanced construction management even with small teams. This easy surveying solution provided by LRTK will surely advance on-site DX and open the path to next-generation smart construction.

FAQ

Q: What equipment is required to introduce AR? A: Basically, you can start with a smartphone or tablet capable of AR display. GPS functionality is important for accurate outdoor alignment, but RTK-GNSS–compatible equipment is useful for higher-precision AR. For example, using a small GNSS receiver that attaches to a smartphone (like LRTK) enables centimeter-class accuracy for AR. However, advanced AR apps or software are also needed, so choose tools that match your intended use.

Q: Is specialist knowledge required to use AR on site? A: No—tools designed to be usable without advanced expertise are increasingly available. Solutions like LRTK provide intuitive operation screens so site staff with basic smartphone skills can perform surveying and AR display. Operation is possible without seasoned surveyors or CAD experts, so with simple training you can deploy AR on site.

Q: What is the difference between ordinary smartphone AR and RTK AR? A: Ordinary smartphone AR (using only GPS and gyros) can have position errors of several meters (several ft). That may be fine for games or simple uses but is too inaccurate for construction management requiring high precision. RTK AR reduces errors to a few centimeters (a few inches) by applying satellite positioning corrections, providing far greater alignment between digital information and reality so it can be relied upon for professional tasks such as design verification and pile-position stake-out.

Q: Can small sites or companies adopt AR technology? A: Yes—small sites often stand to benefit most from AR. Modern AR solutions do not necessarily require expensive specialized equipment and can be used with familiar devices like smartphones and tablets. Systems like LRTK, which leverage smartphones, can be introduced with low initial investment, making them accessible to small and medium-sized construction firms and local authorities. AR directly addresses labor shortages and efficiency, so small teams can see particularly strong benefits.

Q: Will AR make traditional surveying and construction management unnecessary? A: AR is a tool to support field operations, not a replacement for traditional surveying and construction management knowledge. Interpreting AR data correctly and judging quality still requires engineers’ eyes and experience. However, AR automates and streamlines many manual measurements and drawing checks, allowing technicians to focus on higher-level decisions and overall optimization. In other words, AR should be regarded as a complement and enhancer of existing expertise rather than a substitute.