Table of Contents

• What it means to display buried utilities in AR

• Challenges of relying on paper drawings

• Benefits of AR display for buried utility management

• Technologies and preparations required for AR display of buried utilities

• Field implementation examples and growing adoption

• Key points for smooth implementation

• Democratizing high accuracy with LRTK easy surveying

• Conclusion

• FAQ

Buried utilities (water and sewer pipes, gas pipes, power cables, etc.) are lifelines of social infrastructure, but because most of them are hidden beneath the ground, they are not visible in everyday life. Precisely because they are invisible, accidents in which existing pipes are accidentally damaged during roadworks or excavation operations continue to occur. Ruptured aging water pipes can cause large-scale leaks, damage to gas pipes can create the risk of gas leaks or explosions, and severed power cables can cause blackouts—damage to buried assets can seriously disrupt social life. Indeed, damage to buried utilities is reported nationwide every year, and in many cases the cause is that the parties involved “did not accurately know what was buried there.”

To prevent such accidents, great care has traditionally been taken in the maintenance and management of buried utilities. At the completion of installation work, it is common practice to record the routing and depth of pipes by surveying and keep drawings along with photographs. On site, experienced workers typically rely on those drawings and ground markings (burial marks) and proceed while estimating, “the pipe is probably somewhere around here.” As needed, ground-penetrating radar surveys or trial excavations (actually digging to confirm) are also performed to verify the locations of buried assets in advance. However, relying on paper drawings and human intuition has its limits, and it is not easy to accurately picture how pipes intersect underground. In urban roads and other places with complex histories of past repairs, multiple pipes and cables run in all directions, and discrepancies between drawing information and actual site conditions are not uncommon. As a result, stories of workers being startled to find a pipe at a depth they thought would be clear are far from rare.

In short, the biggest challenge in managing buried utilities is “how to make the unseen visible.” If the subsurface situation could be grasped intuitively, near-miss incidents during excavation would obviously be reduced, and inspections of aging pipes and planned replacements could be dramatically streamlined. What has attracted attention in recent years is the “visualization” of buried utilities using AR (augmented reality) technology. Pointing a smartphone or tablet camera at the ground and overlaying virtual representations of underground pipes on that live view—this technology makes it possible to visualize the locations of buried assets as if you could see through the ground. Once a long-held dream, this capability is now becoming practical. The era is dawning when people no longer have to squint at paper drawings to share an intuitive understanding of subsurface conditions on site. A new common sense—“Say goodbye to paper drawings!”—is starting to take root in the field.

What it means to display buried utilities in AR

AR (Augmented Reality) is a technology that overlays digital information such as CG onto the real-world view seen through a camera. Applied to visualization of buried utilities, AR can virtually “make visible” the locations of underground pipelines. For example, if you point a smartphone or tablet camera at the ground, the screen can display water pipes or gas pipes beneath the surface superimposed on the actual scene. Because the display makes it appear as if the ground is transparent and the pipes can be seen, anyone can intuitively understand “what is buried directly beneath these feet and how” at a glance.

However, accurate alignment is essential to display buried utilities correctly in AR. Relying on smartphone GPS can result in errors of several meters, causing virtual pipes to appear in the wrong place. That would be far from “seeing through” the ground and could even create dangers from misidentification. Traditionally, calibration work such as placing markers on site or manually adjusting positions was necessary, but placing markers one by one across extensive buried networks is not realistic. The technologies that solve this problem are described in the next section.

Challenges of relying on paper drawings

In the past, paper drawings and design documents were the only way to understand underground utilities. But relying on paper drawings at the site comes with several issues.

• Information tends to become outdated or inaccurate: The contents of drawings are not always up to date. Even if routing changes or relocations occur after burial, the drawings are not always updated. Older infrastructure is particularly prone to such oversights, and situations can arise in which pipes are not where the drawings indicate, or pipes that were not shown on the drawings turn out to be buried.

• Difficult to interpret on site: It is not easy to correctly locate on the actual ground the pipe positions shown as two-dimensional lines on a drawing. Holding a paper drawing and measuring distances from site reference points with a tape to guess “around here” is laborious. Physical difficulties such as hard-to-spread drawings in wind or rain, or poor visibility inside a dark manhole, also make on-site reading hard.

• Hard to form a spatial image such as depth: Paper drawings may lack clear depiction of pipeline depths or three-dimensional relationships with other pipes. Even if a drawing lists “depth ◯ m (◯ ft),” mentally visualizing that in 3D is difficult and can cause misunderstanding. When multiple pipes overlap vertically, it is extremely challenging to form an accurate image from 2D drawings alone.

• Pre-checks are time-consuming: If the drawing data alone is not trusted, trial excavations or ground-penetrating radar surveys may be conducted. These are time-consuming and costly. Doing multiple trial digs or using expensive survey equipment is inefficient and ideally should be avoided.

Thus, there are limits to managing buried utilities based on paper drawings, and sites have long struggled with the “invisible.” The solution that has emerged is AR visualization of buried utilities, described in the following section.

Benefits of AR display for buried utility management

What changes when buried utilities can be displayed in AR? Here are the main benefits.

• Intuitive understanding of subsurface conditions: Because the pipes are displayed to scale on the screen, anyone can immediately understand the subsurface situation. Even newcomers can grasp “what is buried where” by pointing a smartphone, without relying on the intuition of experienced workers. There is no need to compare drawings and mentally construct a 3D image, so on-site decision-making is dramatically faster.

• Prevention of excavation damage: If the exact locations of buried assets can be confirmed in AR before excavation, accidents like inadvertently damaging a pipe can be greatly reduced. If the routing and depth of pipes are visible in advance, heavy-equipment operators can work more confidently, and the risk of accidental damage to gas or water pipes falls sharply.

• Improved efficiency of surveying and construction: AR display can eliminate many pre-works such as trial excavations and layout marking. Reducing the need to spread drawings, repeatedly verify locations by surveying, or measure multiple times shortens work time. For example, in pile-marking (layout) work, AR can navigate pile positions, allowing quick and accurate marking. Overall, productivity in buried utility construction and inspection improves.

• Effective use of digital records: AR contributes not only as a visualization tool but also to digital transformation (DX) of site record-keeping. For instance, when backfilling a newly installed pipe, scanning the excavation with a smartphone LiDAR before backfilling can automatically generate an accurate 3D model of the buried asset. Storing that data in the cloud allows future personnel to reproduce the pipe position and depth instantly by displaying it in AR on site. There is no need to recreate paper drawings later or spray pipe routes on the road—the digital data can be used directly on site.

• Easier consensus building among stakeholders: AR makes the subsurface situation understandable to everyone, facilitating smooth information sharing and explanations. Roadworks often involve multiple infrastructure operators—water, gas, power, communications—and viewing a shared AR screen reduces misunderstandings compared with each party bringing separate drawings. Showing a client or nearby residents, superimposed on the real scene, “this many pipes run here” provides persuasive explanation. Information that was hard to convey on paper drawings becomes obvious with AR visuals.

Technologies and preparations required for AR display of buried utilities

Accurate AR display of buried utilities requires elements on both the hardware and digital data sides. The key technologies can be divided into two major areas: position measurement and AR platform.

First, the foundation for AR display is the AR platform on a smartphone or tablet. Modern smartphones come with capable AR features, using camera imagery and built-in sensors (IMU) to track device motion and stably render virtual objects. High-end devices now include LiDAR sensors (infrared laser 3D scanning), which can capture the surrounding spatial geometry in real time. LiDAR precisely measures distances and shapes of the ground and structures, enabling virtual pipe models to be overlaid accurately onto the real world and enabling natural occlusion of parts that would be hidden underground. In other words, the stage for fusing real scenery and digital data is almost ready with standalone smartphones.

Next, decisive is high-precision self-positioning. Smartphone GPS alone has too much error, so RTK-GNSS (real-time kinematic positioning) is used to drastically improve positional accuracy. RTK corrects satellite positioning errors, and connecting an RTK-capable GNSS receiver to a smartphone lets the device’s position be tracked in Earth coordinates with errors down to the centimeter level. Achieving centimeter-level positioning once required large tripod-mounted equipment and complex setups, but now ultra-compact RTK receivers weighing a few hundred grams can be attached to a smartphone to achieve comparable accuracy. In Japan, augmentation signals from the quasi-zenith satellite system QZSS (Michibiki) and reference-station networks via the internet are available, enabling real-time centimeter-level positioning outdoors almost anywhere nationwide.

This combination of smartphone + LiDAR + RTK eliminates the need for cumbersome marker placement and manual adjustments, allowing virtual models to be aligned with real-world coordinate systems. If you preload 3D models of buried utilities into an app, simply pointing the smartphone on site will overlay the subsurface models exactly beneath the real ground. Since LiDAR scans the terrain, the virtual pipes appear to be concealed within the soil, and depth relationships are intuitively understandable.

Finally, preparation of the buried-utility data to be displayed is important. To show utilities in AR, you need digital location data for the target pipes and cables. For new construction, design 3D models (such as CIM data) or pre-construction point-cloud measurements can be used. For existing infrastructure, 2D plans and profile drawings can be converted into 3D data by deriving latitude/longitude and elevation, and where necessary, on-site surveying can be performed to obtain accurate coordinates. Once the data is prepared and uploaded to the cloud, it can be called up on-site for AR display. Supported data formats vary by system, but AR platforms that accept common CAD drawings (e.g., DWG), Shapefiles, BIM/CIM models, and point-cloud data have begun to appear.

Field implementation examples and growing adoption

What once seemed like science fiction—“seeing through the ground on site”—is now being put into practice domestically and internationally. In Japan, systems combining tablet devices with RTK positioning have already been developed to display buried utilities in AR on site, allowing three-dimensional understanding of buried assets without drawings or trial excavations. Sites that have adopted these systems report marked improvements in safety and work efficiency. Overseas, technologies that realize centimeter-accuracy AR outdoors have also emerged, drawing attention to systems that perfectly overlay 3D design models onto real scenery on smartphones. Because complex underground infrastructure information can be intuitively shared and verified on site, adoption is being considered especially in countries advanced in infrastructure management.

Thus, initiatives for construction DX using RTK × AR are accelerating both in Japan and abroad, and applications are expanding from bridge construction to urban infrastructure maintenance. These efforts align with initiatives like the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction, making this an area expected to further penetrate field operations.

Key points for smooth implementation

To embed new technology in the field, keep the following points in mind.

• Accuracy and preparation of pipe data: Use the most accurate and reliable buried-utility location data possible. If the drawing’s coordinate system is unclear, correct it by surveying known points; update old information by re-measuring on site. Ensuring data accuracy is crucial. If there are multiple data sources, centralize them and convert/integrate into formats suitable for the AR system.

• Choose a high-accuracy yet user-friendly system: Prioritize ease of use in the field when selecting a system. Methods requiring lengthy initial setup or placement of dedicated markers will not fully leverage AR. A markerless AR solution that supports RTK-GNSS and automatically corrects position allows quick startup by simply powering on the device. Tools with intuitive Japanese UIs for smartphone operation and cloud integration for easy data synchronization can be adopted on site without specialist knowledge.

• Awareness and training for field staff: When introducing new tools, provide explanations and brief training to reduce resistance among workers. Many recent smartphone AR apps are intuitive—almost game-like—and hands-on experience lets users pick up the basics quickly. Once workers see it is often easier than interpreting paper drawings, they are likely to adopt it proactively.

• Start small and scale up: Begin by trying AR display in a limited area or simple cases to verify its effectiveness. If usefulness is demonstrated on a relatively simple pipe route, internal evaluation will rise and help push full deployment. Gradually expand the application scope and share success stories internally to foster field-wide adoption without resistance.

Democratizing high accuracy with LRTK easy surveying

LRTK (pronounced “el-ar-tee-kay”) is a solution that brings the RTK-GNSS technology described above into a form anyone can use with a smartphone. LRTK integrates an ultra-compact high-precision GNSS receiver attached to a smartphone with a dedicated app and cloud services to provide end-to-end positioning, data management, and AR display. The smartphone effectively becomes a centimeter-accurate surveying instrument, and a single device can handle surveying, layout marking, 3D scanning, photogrammetry, and AR visualization—making it a veritable all-purpose surveying tool for the field.

In civil engineering and construction, workflows using LRTK are already being practiced: a single technician can perform surveying and layout marking alone, instantly share obtained point-cloud data and drawing information to the cloud, and use AR projection of buried-utility models for construction management. LRTK is designed so that even those without formal surveyor training can operate it, and smartphone-native workers can master it in a short time. This ease of use combined with high precision has made LRTK a key technology supporting DX in construction, aligning with the i-Construction initiative advocated by the Ministry of Land, Infrastructure, Transport and Tourism.

By adopting LRTK, anyone can obtain centimeter-accurate self-positioning at any time, greatly lowering the barrier for the surveying and coordinate-alignment preparations required for AR display of buried utilities. In effect, the time spent on per-site “position alignment” is eliminated, allowing immediate AR visualization. Not only do paper drawings become unnecessary, but traditional buried-utility management based on experienced intuition can be updated to data-driven smart construction. As simple, high-accuracy tools like LRTK become more widespread, on-site visualization of buried utilities is likely to become the new norm.

※For details on LRTK, please see the [official site](https://www.lrtk.lefixea.com).

Conclusion

AR display of buried utilities on site has the potential to dramatically improve safety and efficiency, overturning conventional practices. Work that once relied on paper drawings and intuition is being transformed into tasks where everyone can share the same “visible” information via a tablet. The fusion of centimeter-level positioning and smartphone AR is ushering in a major shift in subsurface infrastructure management. This technology, emblematic of site DX, is expected to spread further, and the day when “say goodbye to paper drawings” becomes the slogan is not far off. A working style in which construction and excavation proceed while confirming buried utilities in AR is gradually taking hold as the new norm. Why not get ahead of this trend at your site?

FAQ

Q: What is needed to introduce AR display of buried utilities? A: Basically, you need the smartphones or tablets to be used on site, a GNSS receiver capable of high-precision positioning (RTK-capable device), and the location data of the buried utilities you want to visualize. A dedicated AR app (software) that integrates these components is also required. With device + GNSS equipment + data + app, you can display buried utilities in AR on site.

Q: Do I need to procure special or expensive equipment? A: No. Large, tripod-mounted surveying machines are not necessary. High-precision GNSS receivers are now palm-sized and can be attached to smartphones, and their prices are lower than traditional surveying equipment. With a smartphone you already use, a small receiver, and a compatible app, you can implement the solution without investing in exceptionally expensive devices.

Q: How reliable is AR display accuracy? A: Using RTK-GNSS, positioning errors are generally confined to a few centimeters. In good outdoor conditions, deviations can be kept to around 2–3 cm (0.8–1.2 in), allowing underground pipes to be displayed almost exactly where they are. This is far more accurate than the several-meter errors typical of conventional GPS, making it possible to confidently locate buried utilities.

Q: Can AR be used when only old drawings exist? A: Yes. First, convert the pipe information drawn on existing paper drawings into digital data to create AR-ready models. If you are unsure about drawing accuracy, perform simple surveys with LRTK in key locations to correct positions. When AR reveals discrepancies between drawings and actual conditions on site, you can update the data on the spot and save it to the cloud, gradually building an accurate underground map.

Q: Can field workers operate it successfully? A: Yes; it is relatively easy to use. Smartphone apps are designed for intuitive operation and do not require special qualifications. Seeing pipes rendered on the screen makes the concept easy to understand, and both young and veteran workers often get comfortable with the system after brief use. Many say it is easier than interpreting paper drawings.

Q: Can AR glasses (smart glasses) be used instead of smartphones? A: Currently, smartphones and tablets are the mainstream solution. Use of AR glasses (e.g., helmet-mounted displays) is being explored, but issues such as very high cost, battery life, and outdoor visibility remain. For outdoor buried-utility visualization, mobile devices are the realistic choice today. In the future, if devices become smaller, lighter, and more widespread, hands-free confirmation with AR glasses may become feasible.

Q: Is the smartphone actually scanning underground to display pipes? A: No. The smartphone does not literally see through the ground. The pipes visible in AR are virtual models drawn based on pre-acquired and prepared buried-utility location data. Since smartphones cannot directly detect underground features, when no source data exists you must first conduct surveys or record buried assets to create the data. AR does not magically discover unknown pipes; it overlays known information onto the real world in an easy-to-understand way.