Infrastructure Inspection × AR Civil Engineering: A Smart Inspection Revolution for Aging Countermeasures

Table of Contents

• Aging social infrastructure and the importance of inspections

• DX and AR technologies spreading in the construction industry

• Examples of AR use in infrastructure inspection

• Benefits brought by AR introduction

• The smart inspection revolution opened by AR civil engineering

• Simple surveying with LRTK

• FAQ

Aging social infrastructure and the importance of inspections

Much of Japan’s social infrastructure was developed intensively during the high economic growth period (the 1960s–70s), and many of these assets are now facing aging-related issues. There are approximately 700,000 road bridges and about 10,000 road tunnels nationwide, and the number of structures such as water and sewer pipes, port facilities, tunnels, and bridges that are over 50 years since construction is rapidly increasing. To ensure the safety of these infrastructures, the national government requires standardized close-up visual inspections every five years for bridges, tunnels, and the like, and all municipalities and managers implement planned inspections.

However, the sheer scale of inspection targets is colliding with a severe shortage of on-site engineers and workers. In many municipalities, the aging of technical staff who manage infrastructure and the lack of younger workers are progressing, making securing personnel to carry out inspections a major challenge. In fact, it is said that more than half of experienced engineers involved in infrastructure maintenance are 45 years old or older; retirements are occurring one after another while new entrants are declining. As a result, the burden of inspecting and maintaining a vast number of facilities with a limited workforce is increasing, raising concerns about inspection delays, reduced accuracy, and even the risk of accidents caused by overlooking serious deterioration.

Accidents caused by aging infrastructure are by no means someone else’s problem. Serious accidents attributed to infrastructure aging—such as concrete wall collapses and tunnel ceiling slab falls—have occurred domestically and internationally, delivering a major shock to society. Preventing such accidents requires planned inspections and preventive maintenance as countermeasures against aging. However, as noted above, there are limits to current analog-centered inspection methods due to manpower shortages and heavy workloads. What is attracting attention, therefore, is improving efficiency through the use of digital technologies. Through DX (digital transformation) in infrastructure maintenance and management, a shift to “smart inspections” that can ensure safety even with limited personnel is expected.

DX and AR technologies spreading in the construction industry

In recent years, the construction and civil engineering industries have also been undergoing operational reforms driven by digital technologies. Led by the Ministry of Land, Infrastructure, Transport and Tourism’s “i-Construction” initiative and public–private efforts to promote construction DX, on-site digital transformation is accelerating with drone surveying, BIM/CIM (3D models), and AI-based image diagnostics. Among these technologies, one of the most notable is AR (Augmented Reality). AR is a technology that overlays digital information on real-world scenes through a smartphone or tablet, and it is becoming increasingly familiar to the public through applications like Pokémon GO and AR navigation in map apps.

What once seemed like science fiction, AR has become a realistic tool on construction and civil engineering sites thanks to rapid technological advances and higher-performance devices in recent years. A major factor is that advanced AR experiences are now possible not only with dedicated AR glasses (smart glasses) but also with handheld smartphones such as iPhones and Android devices. By using the camera and sensors of smartphones or tablets to display 3D models and guidance on site, AR is expected to enable intuitive spatial understanding. Additionally, because many site personnel are already familiar with smartphones, AR can be introduced without special training, which is an attractive feature.

AR use in construction is being explored across stages from design to construction management and maintenance. For example, on construction sites, teams can share the completed structure’s appearance by displaying life-size AR models, or visualize the positions of buried pipes and cables to reduce excavation risks. Remote support is also possible, where an experienced engineer in another location can provide instructions and advice through AR to on-site workers, holding the potential to change how site work is performed. These cutting-edge applications—sometimes referred to as “AR civil engineering”—are being regarded as promising smart technologies that could become industry standards in the future.

Examples of AR use in infrastructure inspection

AR technology can be applied in various ways on the front lines of infrastructure maintenance and inspection. Here are some specific use cases.

• Deterioration diagnosis by overlaying past data in AR: During inspections of structures such as bridges and tunnels, past design drawings or information on deterioration points recorded in previous surveys can be overlaid on the current structure’s live image using AR. This enables immediate understanding of the progression of deterioration and whether deformations have occurred, allowing precise identification of parts that require repair. By reducing the need to compare paper drawings or photos, and by confirming “the problem right there now” on site, AR helps prevent inspection omissions and improves accuracy.

• Visualization of underground infrastructure: Buried water and sewer pipes, gas pipes, and cables that cannot be seen directly can be visualized with AR as if through a see-through view. If location information or 3D scan data of buried pipes is available in advance, simply pointing a smartphone or tablet camera at the ground can display the underground piping routes in AR. This significantly reduces the risk of accidentally damaging other pipes during excavation and can eliminate the need for exploratory digging when old drawings are inaccurate, making it more efficient to locate buried objects. AR’s ability to visualize the unseen is powerful for underground infrastructure renewal and understanding aging pipes.

• AR measurement and inspection recording: By leveraging a smartphone’s camera and LiDAR sensor, it is possible to measure dimensions and distances of objects directly in AR on the spot. For example, you can measure and display the length or width of a crack in AR, mark its location, and save it as photos or 3D data. Tasks that traditionally required rulers or surveying instruments can be performed more easily, contributing to improved accuracy and reduced labor in inspection records. Because inspection data can be saved to the cloud in digital form, history management and comparison become easy, allowing immediate confirmation of changes from previous values in subsequent inspections.

• Use in remote support and training: AR can also serve as a real-time communication tool linking the field and the office. If an on-site worker shares camera footage via AR, an experienced engineer at a remote location can write virtual markings or instructions on that footage to provide appropriate inspection guidance in real time. This enables less experienced personnel to gain veteran expertise on the spot and respond accurately. AR can also display inspection procedures and checklists for use in training new staff. As a tool that standardizes tasks that once relied on human intuition and experience, AR is promising for enabling everyone to perform inspections to a consistent standard.

Benefits brought by AR introduction

So what concrete benefits can be gained by incorporating AR into infrastructure inspection? The main advantages are summarized below.

• Dramatic improvement in inspection efficiency: Since AR displays necessary information on site immediately, the time spent referring to drawings and documents is reduced, speeding up inspection work. Survey results can be displayed on the screen in real time, and AR navigation can guide you to the next inspection point. As a result, more facilities can be inspected with limited personnel, addressing severe labor shortages.

• Safety assurance and risk reduction: Inspections in high or confined spaces can reduce hazardous postures and long periods of restraint by using AR devices. For example, inspecting from a distance by adding AR annotations to drone footage or checking equipment blind spots with an AR camera can protect workers’ safety. AR visualization also reduces the risk of accidentally damaging other equipment, producing an accident prevention effect.

• Improved accuracy and prevention of oversights: Overlaying digital information with centimeter-level accuracy (half-inch accuracy) makes it harder to miss subtle misalignments and deterioration. Abnormalities overlooked by human visual inspection can be highlighted in AR, increasing detection rates. For instance, combined with crack-detection AI, AR can display AI-detected cracks as AR markings on the spot, approaching zero oversights. Accumulating inspection results as data also helps quantitatively grasp aging changes, contributing to improved accuracy.

• Knowledge transfer and labor-saving: As veteran skilled technicians decline, AR helps skills transfer by visualizing expertise. Intuitive points and cautions known only to experienced personnel can be shared on AR apps and used by anyone. This helps eliminate person-dependent practices and standardize work, enabling less experienced staff to conduct inspections at consistent quality levels. Supporting one person in handling multiple roles makes labor reduction realistic and enables small teams to operate.

• Cost reduction and infrastructure life extension: Improved inspection efficiency and accuracy also reduce unnecessary repairs and emergency responses. Early detection and planned responses to deterioration can prevent major failures or accidents, thereby suppressing repair costs. Conducting repairs and replacements at appropriate timings extends infrastructure assets’ life and is expected to reduce life-cycle costs. For effective use of limited maintenance budgets, smart inspection technologies including AR are powerful allies.

The smart inspection revolution opened by AR civil engineering

The use of AR technology is fundamentally changing how infrastructure inspections are conducted. Inspection tasks that were traditionally done by people relying on “experience and intuition” and visual checks are beginning to transition to data-driven digital processes. AR integrated with sensors and AI can instantly visualize quantitative data collected on site to support decision-making, making inspections more scientific and objective. This transformation rightfully deserves to be called the “smart inspection revolution.”

In practice, efforts to utilize high-precision AR on site have already begun. In Japan, systems combining tablets with high-precision GNSS positioning have been developed that can display buried pipes on site in AR, enabling the location of underground equipment without exploratory digging. Overseas, advanced cases achieving outdoor AR displays with centimeter-level accuracy (half-inch accuracy) have also emerged, drawing attention as symbols of DX in civil engineering. From bridge construction to urban infrastructure maintenance, the adoption of smart construction and smart inspection that fuse the real and the digital is steadily expanding.

Until now, on-site work commonly relied on craftsmen’s experience and checks against paper drawings. But the future where everyone routinely checks structures and underground conditions through AR as they work is near. As an effective countermeasure against aging, on-site digitalization and smartification are paths that cannot be avoided. The spread of AR civil engineering will dramatically improve the quality and efficiency of infrastructure inspections and usher in a revolution in the maintenance of safe and secure social infrastructure.

Simple surveying with LRTK

Finally, we introduce LRTK, a cutting-edge solution that combines AR and GNSS technologies. LRTK is a system consisting of a compact high-precision GNSS receiver (RTK unit) that can be attached to a smartphone and a dedicated app, turning a single smartphone into a universal surveying device capable of centimeter-class positioning (half-inch accuracy). It features ease of use—no complicated initial setup is required, and you can immediately use high-precision positioning and AR displays simply by powering on the device. Whereas conventional AR surveying tools required marker placement and manual alignment adjustments, LRTK eliminates such cumbersome tasks.

With LRTK, surveying, layout staking, and inspection recording tasks that once required specialized equipment can be intuitively handled by a single person. For example, simply walking the site with a smartphone in hand will have AR arrows guide you to specified measurement points. Measurement results are displayed on the ground as virtual markers that can be confirmed and recorded accurately. Obtained point cloud data and design models can be shared to the cloud instantly and displayed in AR on another device easily. The UI is designed so that personnel without specialized knowledge can operate it, enabling anyone to perform advanced surveying and inspection easily.

Introducing LRTK to infrastructure inspection and construction management sites allows rapid, high-precision surveying and recording even with limited staff. As an entry point into AR civil engineering, smartphone-based simple surveying tools like this can accelerate on-site DX at a stroke. For municipalities and companies struggling with aging-countermeasure challenges, LRTK can be a reliable partner in advancing site smartification. Take this opportunity to take the first step toward smart inspections that incorporate the latest technologies.

FAQ

Q: What is AR civil engineering? A: “AR civil engineering” refers broadly to initiatives that utilize AR (Augmented Reality) technology in the construction and civil engineering fields. By bringing smartphones or tablets to the site and overlaying design data and measurement information on camera images, it is a method to streamline construction management and infrastructure inspections. Interest in AR civil engineering has been increasing recently, aided by the Ministry of Land, Infrastructure, Transport and Tourism’s promotion of i-Construction.

Q: What is required to introduce AR into infrastructure inspection? A: Basically, you need an AR-capable device (smartphone, tablet, or AR glasses) and digital data of the inspection targets. For smartphones or tablets, you install and use a dedicated AR app. High-precision technology to accurately align overlays—such as GPS/GNSS, markers, or sensors—is important. If 3D models or drawing data of inspection points are prepared, more useful information can be displayed in AR. Recently, solutions that scan the site with a smartphone camera and directly convert it into inspection data have also emerged.

Q: On site, should we use smart glasses or smartphones? A: At present, AR using smartphones/tablets is mainstream. Dedicated AR glasses (head-mounted displays) are expensive and may be burdensome to wear, whereas smartphones are widely owned by site personnel and familiar to operate. Tablets offer the advantage of a larger screen for easier viewing. On the other hand, AR glasses provide the benefit of hands-free operation, so as devices become smaller, lighter, and less expensive, they may become more widespread. Given current costs and usability, starting with smartphone AR is a realistic approach.

Q: Does introducing AR require high costs? A: Implementation costs vary case by case, but since smartphone and tablet-based methods are mainstream nowadays, it is often possible to start at relatively low cost. Costs will increase if you equip dedicated high-performance hardware and software, but you can feel the effects without large initial investment by first trying commercially available mobile devices and consumer AR apps. Solutions like LRTK, which can be attached to existing smartphones to achieve high-precision AR, offer good cost performance compared to traditional surveying equipment. Of course, required investment depends on scope and target tasks, but considering future efficiency gains and cost reductions, it is an investment that can be well justified.

Q: What is LRTK and what are its benefits? A: LRTK is a solution that converts a smartphone into a high-precision surveying and AR terminal by attaching a compact high-precision GNSS receiver. RTK-GNSS can improve positioning accuracy to a few centimeters (a few in), enabling far more accurate alignment for AR displays on site than before. Using LRTK, a single person can locate stake positions with a smartphone in hand or display acquired 3D data in AR on the spot, streamlining tasks that previously required teams or heavy equipment. It is designed to be operable without specialized knowledge, and simply adopting it can significantly advance on-site DX.

Q: What is the outlook for AR technology? A: AR technology will continue to evolve, expanding its application range in infrastructure maintenance and management. On the hardware side, devices will become smaller, lighter, and more wearable, making it possible to check AR information without hindering work. Combined with AI-based automatic analysis, advanced features such as automatically detecting and displaying abnormalities simply by pointing a camera at the site could become feasible. Integration with cloud services and IoT for real-time monitoring will also progress, and inspection tasks themselves are expected to become more labor-saving and automated. As these technologies mature and costs decrease, it’s likely that not only smartphones but all site staff will routinely use AR. Consequently, the quality and speed of infrastructure inspection will dramatically improve, greatly contributing to ensuring the safety of aging infrastructure.