Latest AR Civil Engineering Developments: Technological Innovation Advancing on Site

Table of Contents

• New possibilities AR technology brings to civil engineering construction sites

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

• Benefits of introducing AR

• What is the latest AR technology with LRTK

• Simplified surveying with LRTK

• FAQ

In recent years, the use of AR (augmented reality) technology has been advancing on construction and civil engineering sites. Initiatives that overlay 3D design models and construction information onto real-world scenes via smartphones and tablets have attracted attention, enabling intuitive visualization of construction progress and completion images by superimposing virtual objects on site views. This brings many benefits such as reducing construction errors, streamlining quality checks, and promoting information sharing between project owners and sites.

However, conventional smartphone AR often suffers from alignment errors of several meters (several ft), and it has been a challenge to meet the centimeter-level accuracy required for civil construction management and surveying. In recent years, the combination with satellite positioning RTK (Real-Time Kinematic) technology has attracted attention. By using the RTK method to correct satellite positioning errors in real time, smartphone AR misalignment can be reduced to about a few centimeters (a few in), enabling high-precision AR display.

Such “RTK-enabled AR” technology is expected as a new solution supporting the construction industry’s DX (digital transformation). Within initiatives like the Ministry of Land, Infrastructure, Transport and Tourism–led *i-Construction* and the trend toward construction ICT, it is gaining attention as a promising tool to enhance and streamline on-site operations. This article introduces the revolutionary changes AR technology brings to civil construction sites and concrete use cases, and concludes with an explanation of the latest AR solution using the smartphone surveying tool LRTK.

New possibilities AR technology brings to civil engineering construction sites

With the introduction of AR, construction management tasks that used to require mentally matching paper drawings to the site are beginning to change dramatically. Because digital design information can be overlaid on the actual construction site and checked on the spot, data-driven construction management that does not rely on experience or intuition has become possible. Layout marking (setting out) and as-built checks, which tended to depend on veteran skills, can be performed accurately by anyone with AR guidance. AR greatly contributes to early detection of surveying and construction errors that occur during work and to reducing rework. In fact, there are reported cases where displaying design drawings on site with AR enabled immediate correction of construction defects, preventing later rework and material waste.

Furthermore, AR is a technology that addresses labor shortages and skill succession issues in the construction and civil engineering industries. From major general contractors to local small and medium-sized contractors, heavy equipment operators and site supervisors are beginning to use AR in practice. For example, in earthwork projects, an operator can project the designed finished terrain model onto reality through a tablet and perform excavation and fill while confirming heights. In foundation work, site supervisors can display foundation layout on AR so that structures can be installed accurately even in the absence of experienced personnel. In this way, AR raises the quality and efficiency of on-site work, and its potential impact on construction management is significant.

AR use cases in civil engineering construction

Now let's look at concrete examples of how AR is used on civil construction sites.

Pile driving guidance (streamlining pile layout with AR)

To install piles at the correct positions that form the foundation of structures, it is essential before construction starts to perform layout setting out on site based on coordinates on drawings. Traditionally, pile layout has been done by surveying teams measuring distances from reference points using total stations or tape measures and installing stakes or batter boards on the ground. However, manual layout work requires high levels of skill, takes considerable time and effort, and can become difficult in certain terrain or weather conditions; even small surveying errors can lead to later construction mistakes.

By using RTK-enabled AR, such pile layout work can be revolutionarily streamlined. Through a smartphone or tablet screen, virtual piles or markers (AR markers) can be displayed at the positions specified in the drawings, so workers can simply move toward the markers superimposed on the real scene to identify the designated points. The screen shows real-time arrows and distance information, guiding workers to the pile positions like a construction-site GPS navigator. As you approach the correct position, fine distances such as “x cm (x in) remaining” are displayed on the screen, and when the target point is reached, the virtual pile and the real marker align perfectly and the positioning is confirmed. Even inexperienced staff can intuitively determine accurate pile positions, enabling layout work to be completed in a short time without relying on veteran intuition.

On sites that have introduced RTK-enabled AR, the time required for pile marking has been dramatically reduced compared with conventional methods. There are reports where pile layout that previously took several people half a day was completed quickly by a single person. This directly leads to workforce reduction and cost savings, and because positioning can be done with centimeter accuracy (half-inch accuracy), little rework is needed in subsequent processes. It also improves safety, since pile positions can be confirmed and guided from a safe distance rather than entering dangerous heavy-equipment operating areas or areas with poor footing. Even on concrete pavements where physical stakes cannot be placed or on steep slopes, AR displays can accurately indicate pile positions.

As-built management (instant on-site verification with AR)

In civil works, as-built management—confirming that completed structures or formed ground match the design geometry and dimensions—is an important process. Traditionally, after work completion, surveying personnel would measure heights and positions in detail on site and compare the returned data with drawings to verify quality. This process inevitably takes time, and organizing and analyzing measurement data requires effort.

With AR, much of as-built management can be performed in real time on site. For example, the designed finished model or reference height lines can be displayed in AR over the actual object to directly check post-construction structures. For road embankment works, projecting a preconfigured design finished-line onto the ground allows intuitive AR guidance: when the earth is filled until the line disappears, the result matches the design. After finishing, you can overlay the completed terrain and the design model on the smartphone camera image to check even minute bumps or shortages. Errors of a few centimeters (a few in) that were previously easy to overlook can be identified at a glance with AR, enabling additional cutting or filling instructions on the spot.

Moreover, systems like LRTK can immediately acquire high-precision 3D point cloud data on site using the smartphone’s built-in LiDAR scanner or photogrammetry functions, enabling comparison with design data. Acquired point clouds have absolute global positioning coordinates, so uploading them to the cloud and overlaying them with design models allows automatic calculation of volume and cross-section differences. Even complex terrain as-built verification can yield quick, detailed analyses such as which parts should be cut or filled by how many centimeters, dramatically improving the accuracy and speed of as-built management. The measured data can also be used directly for as-built drawings and reports, greatly streamlining those tasks.

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

Accurately understanding land boundaries and construction limits is a critical task for surveyors and construction managers. However, boundary lines are often only shown on drawings and are not visible on site. Even if existing boundary stakes or markers exist, they may be hidden by vegetation or terrain, and in some cases boundary points are not clearly indicated at all. Confirming and sharing boundaries has therefore been time-consuming and carried the risk of disputes due to misidentification.

RTK-enabled AR technology can visualize map boundary lines directly on site. If land boundary coordinate data is pre-registered in the system, simply pointing a smartphone camera at the site will render the specified boundary lines clearly in space. Even on vacant land with no visible markers, the screen will display boundary lines that would otherwise be invisible, so you can immediately understand “where the site begins and ends.” RTK's centimeter-level accuracy (half-inch accuracy) allows boundary lines based on cadastral maps or design drawings to be shown at their true positions, eliminating on-site recognition discrepancies.

This AR boundary-line display is useful in various situations such as land surveying, land acquisition attendance, and pre-checking construction extents. For example, in road widening planning, it can be difficult to convey boundary lines or planned road widths to local residents using only paper drawings, but projecting boundary lines and finished road widths on site with AR allows anyone to intuitively understand the situation, smoothing consensus building. During construction, heavy-equipment operators can refer to AR-displayed work-area lines to avoid excessive excavation or encroachment. Visualizing these otherwise “invisible” boundary lines greatly improves the efficiency of boundary confirmation and helps prevent disputes.

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

One of the purposes of using design data (3D CAD, BIM/CIM models, etc.) on construction sites is to eliminate discrepancies between design and construction. AR-based design model verification refers to overlaying the 3D design model onto the real scene and directly comparing it with the structure during or after construction. Because RTK-enabled AR ensures precise alignment between the model and reality, it becomes possible to immediately check on site “Is this being built as designed?”

For example, in bridge construction when installing bolts or columns, displaying the design position guides on a smartphone AR screen helps prevent misalignment during component installation. Reinforcement placement and piping installation can also be carried out accurately by projecting the finished 3D model in AR so workers can constantly compare the model with the actual work. If positions or heights are off by even a few centimeters (a few in), the discrepancy between the model and the actual object becomes evident at a glance. RTK-enabled AR does not provide millimeter-level precision, but it offers sufficient accuracy for on-site judgment whether deviations are within acceptable ranges for construction management.

Such AR verification enables early detection of construction errors and prevention of rework. Minor deviations that would have been discovered only by post-completion surveying can be detected and corrected during construction with AR, reducing wasteful dismantling and rework later. When the project owner or site supervisor views the AR imagery together for checks, mistakes caused by differences in recognition can also be avoided. Sharing a digital “finished form” among all stakeholders during construction makes data-driven construction management possible without relying on veteran intuition. AR can also be used before work begins to project the finished model on site to check for interference between structures or to preview the post-construction appearance. These practices are highly effective for on-site consensus building and quality assurance.

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

Recently, cases of using 3D point cloud data acquired by drones or laser scanners for construction management have increased. Point clouds are collections of countless measured points that digitally represent the shapes of terrain and structures in detail. Using RTK-enabled AR technology, this point cloud data can be displayed on site in AR and overlaid with design models or the actual scene for comparison.

For example, after an operator completes excavation and filling on an earthwork project, suppose they scan the site with a smartphone’s LiDAR to acquire point cloud data. Because RTK gives the point cloud absolute coordinates, the data can be handled in exactly the same coordinate system as the design ground model. If the tablet screen simultaneously displays the design model and the acquired point cloud in AR, protruding or deficient parts due to overfilling or underfilling become immediately distinguishable as shape mismatches or color differences. The major advantage here is the ability to check the as-built intuitively on site rather than comparing point clouds and design data back in the office after completion.

It is also possible to overlay point clouds acquired at different times in AR to observe aging or changes during periodic inspections of existing structures. While complex point cloud data is typically analyzed using specialized software, overlaying it in AR allows differences to be understood with an on-site feel. Acquired point cloud data can of course be used in the cloud for detailed analysis and volume calculations, but AR display complements this as an intuitive verification method. RTK-enabled AR point cloud comparison is a powerful tool for quickly detecting discrepancies between design and actual conditions, raising the precision of quality control and as-built verification.

Benefits of introducing AR

Introducing AR technology on site yields many benefits, such as the following.

• Improved surveying accuracy: Using high-precision GNSS at the centimeter-class increases the reliability of position information displayed in AR dramatically. It becomes possible to set out boundary lines and structure positions from drawings without error, enabling meticulous construction management that was previously difficult. Work can be carried out accurately based on data rather than relying on veteran workers’ intuition.

• Operational efficiency and labor savings: Time required for surveying, layout setting out, and as-built verification can be greatly reduced. Following AR guidance allows work to be done by the shortest routes and minimal steps, enabling one person to perform tasks that previously required multiple people. For example, pile layout that once took several people half a day may be completed quickly by one person, a dramatic efficiency improvement that leads to reduced labor costs and shorter schedules.

• Improved safety: AR reduces the risk of workers entering hazardous areas. As noted above, layout work that required entering heavy-equipment operation zones can be done from a safe distance using AR guidance. Completing surveying and verification tasks in a short time also reduces work in bad weather or at night, contributing to safety management.

• Smoother communication and consensus building: Digital information can be shared intuitively on site, smoothing communication among stakeholders. For project owners, site staff, and local residents, demonstrating the finished image or boundary lines with AR produces the “seeing is believing” effect. Sharing spatial images that were hard to convey with drawings prevents misunderstandings that lead to rework or complaints.

• Data utilization and promotion of on-site DX: Introducing RTK-enabled AR itself advances on-site digitization significantly. With positioning data, point clouds, and photo records managed centrally in the cloud, office data整理 tasks after returning from site are reduced. Accumulated data can be used for analyses and reporting linked with BIM/CIM models, contributing to overall DX. As represented by *i-Construction*, on-site use of 3D data is becoming a requirement for public works, and the ability to handle advanced digital construction will strengthen a company’s competitiveness.

What is the latest AR technology with LRTK

Finally, as a concrete solution for easily introducing RTK-enabled AR on site, we introduce LRTK. LRTK is an all-in-one on-site DX tool that enables both high-precision positioning and AR display with a single smartphone. By attaching a dedicated ultra-compact RTK-GNSS receiver (palm-sized) to a smartphone and launching the companion app, an everyday smartphone quickly transforms into a centimeter-class surveying instrument. There is no need for complicated initial calibration or marker installation; turn it on and you can immediately use high-precision AR.

With LRTK, design coordinate data and survey data are uploaded to the cloud in advance and synchronized with on-site terminals for use. For example, if a coordinate list of pile positions is registered in the cloud, selecting it on site starts AR navigation and lets anyone display virtual piles and receive coordinate guidance as described above. Similarly, importing line data from drawings enables AR display of boundary or planned lines, and uploading point cloud data allows on-the-spot comparison of current conditions and design. These operations are provided through an intuitive UI designed so that even non-surveying specialists can use them.

Using LRTK, which completes everything from surveying measurements to AR visualization with just a smartphone, work on site can proceed under a one-device-per-person system. Tasks that previously required separate equipment and software—surveying, layout setting out, as-built scanning, photo recording, and design verification—can be integrated and coordinated on a single platform with LRTK, achieving a dramatic increase in efficiency. Feedback from sites that have adopted LRTK includes comments such as “young employees could perform surveying and pile layout without issues” and “real-time cloud recording made reporting much easier.” Its low-cost entry point without needing expensive dedicated equipment makes LRTK attractive and accessible to small contractors and local governments that had previously been detached from ICT construction.

To fully realize the potential of RTK-enabled AR, choosing tools that are easy to use on site is key. LRTK, as a representative example, provides a practical solution that balances simplified surveying and high-precision AR display. If you are considering introducing RTK-enabled AR, be sure to consider LRTK as an option. Experience next-generation smart construction realized with a smartphone on site.

Simplified surveying with LRTK

LRTK’s simplified surveying revolutionizes traditional surveying tasks. With just a smartphone and a compact GNSS receiver, anyone can handle centimeter-class positioning, dramatically improving on-site surveying accuracy and work efficiency. Without relying on specialized personnel or expensive equipment, a single smartphone per person can perform coordinate measurement, pile driving guidance, and as-built verification, enabling advanced construction management even with a small crew. This easy surveying solution provided by LRTK steadily advances on-site DX and paves the way to next-generation smart construction.

FAQ

Q: What equipment is required to introduce AR? A: Basically, you can get started with a smartphone or tablet capable of AR display. GPS functionality is important for accurate outdoor alignment, and for higher-precision AR an RTK-capable GNSS receiver is useful. For example, using a small GNSS receiver that attaches to a smartphone (such as those used with LRTK) enables AR use with centimeter-class accuracy (half-inch accuracy). Note that advanced AR apps or dedicated software may also be required, so choose tools that match your intended use.

Q: Do I need specialized knowledge to use AR on site? A: No. More tools are designed to be usable without advanced specialist knowledge. Solutions like LRTK have intuitive operation screens, and site staff who can perform basic smartphone operations can conduct surveying and AR display themselves. They can be deployed on site with only simple training and do not require experienced surveying or CAD specialists.

Q: What is the difference between regular smartphone AR and RTK-enabled AR? A: Regular smartphone AR (using only GPS and gyroscopes) can have position errors of several meters (several ft). That may be fine for simple applications like games, but the error is too large for high-precision needs such as construction management. RTK-enabled AR reduces positioning errors to a few centimeters (a few in) by correcting satellite positioning, achieving much higher alignment between digital information and reality and making it suitable for professional uses like design verification and pile positioning.

Q: Can small sites or companies introduce AR technology? A: Yes. In fact, sites with limited personnel are likely to benefit more from AR technology. Recent AR solutions do not require expensive dedicated equipment and can be used on familiar devices like smartphones and tablets. Systems that leverage smartphones, such as LRTK, make it possible to introduce AR with low initial investment, so small and medium-sized contractors and local governments can adopt it. AR directly addresses labor shortages and operational efficiency, so small teams can make especially effective use of it.

Q: Will AR make traditional surveying and construction management unnecessary? A: AR is a tool to support on-site operations and does not make traditional surveying and construction management knowledge completely unnecessary. Interpreting AR-provided data correctly and judging quality still require the eyes and experience of technicians. However, because AR automates and streamlines many manual measurements and drawing comparisons, technicians can focus more on higher-level judgments and overall optimization. In other words, AR should be regarded as complementing and enhancing traditional techniques, not replacing them.