The Ministry of Land, Infrastructure and Transport Also Promotes It! The World of i-Construction Realized with AR Civil Engineering

Table of Contents

• What is AR civil engineering?

• i-Construction promoted by the Ministry of Land, Infrastructure and Transport and AR technology

• Benefits AR technology brings to civil engineering

• Use cases of AR civil engineering

• Challenges in AR utilization and solutions with RTK

• Simple surveying anyone can do with RTK×AR (use of LRTK)

• FAQ (Frequently Asked Questions)

What is AR civil engineering?

A bridge planned for completion appears to float in lifelike detail over a construction site when viewed through a smartphone — such scenes are increasingly becoming reality in the world of civil engineering. Efforts to “visualize” work that used to rely on drawings and craftsmen’s intuition through digital technology are spreading. In practice, there are now systems that display a virtual stake at the drawing-specified location simply by pointing a smartphone at the site, enabling even inexperienced personnel to indicate survey points accurately. One of the technologies gaining attention in recent years in construction and civil engineering sites is AR (Augmented Reality). AR is the technology that overlays digital information on real-world scenery, allowing virtual objects and text to be displayed on the screen of a smartphone or tablet, or through dedicated smart glasses, over the view in front of you. This “reality × digital” fusion makes it possible to intuitively grasp information that previously could only be checked via drawings or numerical data. AR civil engineering refers broadly to efforts to apply AR technology in the civil engineering and construction sectors, and adoption is beginning across many stages, from planning construction to on-site work support. Tasks that used to depend on the experience and intuition of veterans can be “visualized” with AR so that anyone can understand them more easily, which is expected to improve work efficiency and accuracy. In recent years, smartphone apps with AR functionality have also emerged, making it increasingly feasible to use AR on site without special goggles.

i-Construction promoted by the Ministry of Land, Infrastructure and Transport and AR technology

Japan’s Ministry of Land, Infrastructure and Transport has been promoting the initiative called i-Construction since 2016 as a productivity revolution for construction sites. i-Construction actively introduces advanced technologies such as ICT (information and communication technology), robotics, and AI to achieve smart construction sites that can operate safely and efficiently with fewer personnel. The aim is to improve productivity and advance work-style reforms as countermeasures against labor shortages due to a declining birthrate and aging population, and against aging infrastructure. In fact, the number of construction workers in Japan has decreased by about 30% from its peak, and the aging of skilled site workers has become conspicuous. In surveying, technicians aged 55 and older account for nearly 40% of the total, while young entrants remain at only about 10%; if this continues, there are concerns about the break in the succession of skilled techniques and work stagnation. Against this backdrop, improving productivity and reducing manpower have become urgent issues. Furthermore, in 2024 the policy was strengthened as “i-Construction 2.0,” which set out three pillars for construction sites: (1) “automation of construction” through automation and remote control of construction machinery, (2) “automation of data linkage” through leveraging BIM/CIM data, and (3) “automation of construction management” using AR and digital twin technologies. In particular, in area (3) efforts have been intensified to project 3D models and as-built control diagrams created during the construction phase onto the field using AR technology to aid surveying and inspection. Combining AR with the digital twin technology that reproduces site conditions as data also makes advanced uses such as remotely supervising construction processes conceivable. With this national backing, the construction industry has recently been accelerating construction DX (digital transformation), and on-site adoption of AR technology has attracted even more attention. The Ministry has a target of reducing manpower on construction sites by 30% (increasing productivity by 1.5 times) by 2040, and further use of digital technologies, including AR, is seen as the key. In real construction sites, trials of as-built inspections and remote on-site presence using AR have been conducted, with reported results such as shortened inspection times.

Benefits AR technology brings to civil engineering

So what concrete benefits does AR offer when applied to civil engineering works? Here are the main advantages.

• Intuitive 3D visualization: Information that is hard to understand from drawings and numbers alone can be overlaid in three dimensions on the site scenery, allowing anyone to grasp the content intuitively. Because the completion image and the placement of structures can be visualized on site, stakeholders’ shared understanding deepens, reducing rework caused by communication gaps or misinterpretation. It also reduces the difference in information comprehension between veterans and younger staff.

• Improved work efficiency and reduced manpower: AR navigation can guide work procedures and automate layout tasks, enabling faster construction with fewer personnel. Surveying and marking work that previously required 2–3 people can be handled by one person using AR, allowing productivity to be maintained even at sites with labor shortages. As a result, it contributes to reductions in labor costs and shortening of construction schedules.

• Improved accuracy and fewer mistakes: Even in surveying and as-built inspections that require centimeter-level accuracy (half-inch accuracy), overlaying virtual models on real objects with AR makes it possible to instantly detect misalignments. Because digital data are displayed directly, human reading errors and recording mistakes are reduced, preventing rework and construction errors. This accumulation leads to improved quality control standards.

• Improved safety: Shorter work times reduce the burden of working in harsh environments such as extreme heat or at night. For example, reducing the time required for surveying on roads lowers the risk of traffic accidents. AR can also be used to visualize hazardous areas and no-entry zones, contributing to heightened safety awareness among workers. Such efforts are expected to reduce the risk of accidents and disasters.

• Contribution to skill transfer and human resource development: By embedding veteran know-how into AR systems, even inexperienced workers can perform at a certain standard by simply following machine instructions. The intuitive operation enables quicker proficiency, helping to eliminate dependence on individual skill and to make training of new workers more efficient. It also allows organizations to share know-how and reduce variability in skills across the workforce.

Overall, the adoption of AR is expected to streamline and sophisticate on-site work, significantly contributing to alleviating labor shortages and improving quality and safety.

Use cases of AR civil engineering

Next, let’s look at representative scenes of how AR technology is actually used on civil engineering sites.

• Use in the design stage: AR can display completion models of planned roads, bridges, and buildings on site so that harmony with the surrounding environment and landscape can be verified. Because it enables sharing of completion images that cannot be understood from drawings alone, explanations to clients and local residents become easier and it helps consider design changes. This smooths plan adjustments and consensus building taking topography into account.

• Use in surveying and staking: By using a smartphone or tablet to project reference points or stake positions from the design drawings onto the ground with AR, workers can use virtual stakes or markings displayed on the screen as markers to accurately set out positions. This reduces manual measuring and marking work, enabling even inexperienced personnel to quickly determine stake positions. It should reduce measurement mistakes that accompanied traditional manual work.

• Use in construction management and inspection: For completed structures, pre-created 3D design data can be composited with AR for verifying as-built conditions and quality inspections. Because construction-stage errors and dimensional deviations can be visually detected on site, rework can be prevented in advance. There are also attempts where supervisors in remote locations share AR images from the site to give instructions and perform inspections remotely. This allows on-site verification without relying on paper as-built drawings and tables, contributing to paperless operations.

• Visualization of buried utilities: The locations of underground water/sewer pipes and cables can be displayed with AR to prevent accidental digging during excavation. If data on buried utilities (such as GIS data) are prepared in advance, virtual piping routes will appear above the ground on site, aiding safe construction planning. This can prevent accidents that damage piping and delays in construction schedules.

• Engineer training and remote support: AR-based training materials can be used in on-site training to simulate heavy equipment operation and construction procedures, or to project demonstrations by veteran engineers for newcomers to replay, which is promising for education. Furthermore, experts can add real-time AR annotations to camera feeds from workers on site to provide remote guidance, enabling accurate support even when not physically present. This allows necessary instructions and training to be provided on site even in the absence of skilled personnel.

As such, AR technology can be applied widely from planning through construction and maintenance, bringing new value to civil engineering sites.

Challenges in AR utilization and solutions with RTK

Although AR is convenient, there are challenges that must be overcome for full-scale on-site use. Issues often pointed out include the high cost of dedicated devices, screen visibility outdoors, and the need to prepare 3D data for AR in advance, but the particularly critical problem is the accuracy of alignment. Unlike indoor AR that uses markers, when displaying virtual models in large outdoor sites relying only on smartphone sensors and GPS, a phenomenon called drift tends to occur where the display gradually shifts as the user moves. If the position shifts by several meters (several ft), it cannot be used for surveying or installing structures that require precision. The key technology that solved this problem was high-precision positioning technology RTK. RTK (Real Time Kinematic) is a method that uses GNSS satellite signals such as GPS and applies real-time corrections to reduce positioning errors to several centimeters (several in). By subtracting errors using the differences in satellite data observed at a base station and a rover, RTK can dramatically reduce positioning errors that are normally on the order of several meters (several ft). By basing AR displays on the accurate coordinates provided by RTK, discrepancies between virtual objects and reality can be reduced to almost zero. This enables stable displays without markers over long work periods, making AR practical as an on-site business tool even in wide outdoor construction sites.

Simple surveying anyone can do with RTK×AR (use of LRTK)

Combining RTK’s centimeter-level positioning (half-inch accuracy) with AR displays has given rise to one of the emerging innovative solutions: simple surveying. Surveying work that traditionally required a pair of skilled surveyors can be performed by a single person using RTK and AR. For example, with a pocket-sized RTK-GNSS receiver that can be attached to a smartphone and a dedicated AR app, it is possible to measure target points and set out stakes with just a smartphone in hand, without carrying heavy tripods or special equipment. By following the markers displayed on the screen and pressing a button when arriving at the designated position, high-precision coordinates are instantly recorded. Complex surveying calculations and field notebooks are unnecessary; even beginners can reliably acquire survey points by following machine guidance. AR navigation indicates stake positions without error, allowing inexperienced workers to place stakes at exact target locations. Furthermore, using a smartphone equipped with a LiDAR sensor makes it possible to scan the surroundings while walking and obtain high-density 3D point cloud data. Because the acquired point cloud is automatically tagged with accurate coordinates from RTK, it can be immediately used on site for as-built shape checks and earthwork quantity calculations.

In this way, new surveying methods using RTK×AR promote standardization and automation of surveying work. The acquired data can be shared via the cloud immediately, and as-built checks and quantity calculations can be performed on the spot. The days required for surveying have been greatly reduced, and processes that used to take several days including as-built inspections and reporting can in some cases be completed the same day. Reduced work time also lowers on-site accident risk, yielding benefits in both efficiency and safety. The shift from manual labor to digital measurement has also reduced human errors.

Nowadays, RTK-compatible smartphone surveying systems such as LRTK have appeared, and an era is approaching in which high-precision location information can be handled easily by anyone. Compared with traditional large and expensive surveying equipment, the lower initial cost and operational hurdles are also attractive. LRTK is designed so that, with a small GNSS receiver attached to a smartphone and an easy-to-use surveying app, high-precision positioning and AR-based position checks can be performed on site without specialized knowledge. Because it can be operated without relying on experts, it is easier for small construction companies to introduce and helps raise the overall capability of sites. It is truly a solution that embodies “surveying anyone can do,” and a strong ally for sites facing labor shortages and an aging workforce. The spread of such cutting-edge technologies will greatly contribute to the i-Construction理念 of the Ministry of Land, Infrastructure and Transport, such as achieving a 1.5x improvement in productivity and workforce reduction.

FAQ (Frequently Asked Questions)

Q: What is AR civil engineering? A: AR civil engineering is a general term for initiatives that use AR (augmented reality) technology in the civil engineering and construction sectors. By overlaying digital information on the real world, it is possible to visualize drawings and plans on site intuitively, which can improve work efficiency and accuracy.

Q: What is i-Construction? A: i-Construction is a productivity improvement initiative for construction sites proposed by the Ministry of Land, Infrastructure and Transport. It uses ICT and automation technologies to achieve manpower reduction and efficiency. It started in 2016. With the goal of reducing manpower on construction sites by 30% (increasing productivity by 1.5 times) by 2040, from 2024 it has been promoted as “i-Construction 2.0,” further encouraging the use of digital technologies such as construction machinery automation, data linkage, and AR-based construction management.

Q: How is AR technology used on construction sites? A: AR technology is used in various aspects of construction, such as confirming completion images during the design stage, supporting stake-out in surveying, performing as-built inspections after construction, visualizing the positions of buried utilities, and for newcomer training and remote support. For example, in surveying, virtual stakes displayed on a smartphone screen can be used as markers, enabling accurate staking even by inexperienced personnel. Introducing AR across such processes steadily advances on-site DX.

Q: Can surveying be easily performed with AR? A: Yes. Recently, smartphone surveying systems compatible with RTK-GNSS (e.g., LRTK) have appeared, allowing people without specialized skills to perform centimeter-level surveying in a short time. Because you simply operate according to AR visual guidance, accurate measurements can be obtained without the advanced surveying knowledge that used to be necessary.

Q: Will AR technology spread in the construction industry in the future? A: Yes, it is expected to spread. With the national promotion of i-Construction and growing recognition of AR’s usefulness, device miniaturization and lower costs are progressing, and AR is likely to be integrated into traditional construction workflows more and more. Because it is a technology familiar to younger generations of engineers, AR’s spread will also be a strong tailwind for securing human resources and creating attractive worksites.

Q: What is the difference between AR and VR? A: AR (augmented reality) overlays digital information on real-world scenery and is suitable for supporting on-site work. VR (virtual reality) reproduces entire virtual spaces on a computer and is mainly used for design reviews and simulation training. For example, AR allows you to check designed objects while standing on site, whereas VR is used to train work procedures in a virtual space. Because AR interacts with the real world and VR is completely virtual, their purposes and applications differ and they are used accordingly.

Q: What kind of system is LRTK? A: LRTK is the name of a high-precision surveying system that combines a smartphone with RTK-GNSS. A pocket-sized GNSS receiver is attached to a smartphone and used with a dedicated app to perform positioning and surveying while viewing AR guidance. It enables centimeter-class surveying (half-inch accuracy) without specialized knowledge and is an innovative tool supporting on-site DX.