Visualizing Underground Utilities with AR! Preventing Construction Mistakes and Improving Inspection Accuracy for Peace of Mind

Table of Contents

• Introduction

• The challenges of underground utilities and construction mistakes

• What it means to visualize underground utilities with AR

• Why AR visualization can prevent construction mistakes

• Improving inspection accuracy by using AR

• Key points to keep in mind when introducing AR

• Easier AR use with simple surveying using LRTK

• FAQ

Introduction

Various infrastructure facilities are buried beneath the ground at construction sites. Water pipes, sewer pipes, gas pipes, power cables, communication cables—lifelines that support our daily lives—are laid underground. If these buried utilities are accidentally damaged during excavation or piling work, there is a risk of serious accidents such as explosions or fires from gas leaks, water outages or power outages, and large-scale communication disruptions. In fact, more than 100 incidents of damage to underground utilities are reported domestically each year, making safety assurance and prevention of construction mistakes an important issue.

To prevent accidents caused by underground utilities, it is essential to accurately understand in advance what is buried under the construction site and where it is located. However, because the underground is not visible, traditionally workers had to rely on drawings and records of installation locations. Old drawings may have misaligned positions or pipelines that were not updated. There are also methods to investigate buried objects with metal detectors or radar surveys, but they require specialized equipment and effort and do not guarantee 100% detection. On site, workers can only excavate cautiously while guessing “there should be a gas pipe around here,” and less experienced workers face a higher risk of mistakes.

In recent years, AR (augmented reality) technology for “visualizing” underground utilities has attracted attention. AR is a technology that overlays computer-generated information on camera images from a smartphone or tablet. Using AR, the positions of pipes and cables hidden underground and not directly visible can be displayed on the device screen as if viewed through the ground. For example, when a worker holds up a smartphone, a water pipe buried under the road might be displayed as a blue line. By making the unseen “visible,” AR makes it easier to plan safe construction that avoids underground utilities, allowing heavy equipment operators and workers to perform their tasks with greater confidence. AR display also enables efficient checks during post-construction infrastructure inspections when the underground equipment locations can be confirmed. The use of AR technology is expected to prevent construction mistakes and improve inspection accuracy, providing reassurance to all stakeholders. This article explains in detail how AR visualizes underground utilities, its benefits, and points to consider for implementation. At the end of the article, we also introduce a method using a new technology called “LRTK” that enables anyone to perform high-precision surveying easily.

The challenges of underground utilities and construction mistakes

To prevent accidents caused by underground utilities, it is necessary to identify installation locations before starting work and to ensure proper caution on site. In practice, drawings of installed pipes and cables are requested from relevant parties in advance, and the ground at the worksite is typically marked with spray paint, such as “Gas pipe here.” Trial excavations (carefully digging in advance to confirm) or surveys using detectors are also performed as needed. However, the accuracy and update status of drawings vary, so markings may be slightly off, or buried utilities not shown on the drawings may exist. Even with careful investigation, human error cannot be completely eliminated.

Against this backdrop, major accidents involving underground utilities continue to occur. In the 1980s, more than 300 incidents occurred annually, but strengthened measures later temporarily reduced that to under 100 incidents. Recently, however, the number has hovered around 150–200 incidents per year, and on-site risk remains high. For example, if a gas pipe is accidentally damaged, the surrounding area becomes dangerous, work is halted, and restoration and compensation require enormous effort and cost. For contractors, it can lead to a loss of trust, and for clients and managers it becomes a serious headache. Underground utilities and construction mistakes remain a major issue that needs to be resolved.

The main challenges are summarized below:

• Invisible buried utilities: Workers cannot intuitively grasp what is buried underground, making it difficult to visualize positions.

• Variability in information accuracy: If drawings or ledgers are old or inaccurate, discrepancies with actual installation positions can occur.

• Burden of pre-investigation: Investigations and marking before excavation are time-consuming and labor-intensive, placing a heavy burden on the site.

• Human error: It is difficult to completely eliminate human errors such as overlooking drawings, marking mistakes, or misunderstandings.

• Impact in the event of an accident: If a buried utility is damaged, it not only poses safety risks but also leads to schedule delays, economic losses, and reduced social trust.

What it means to visualize underground utilities with AR

So what exactly does it mean to “visualize” underground utilities using AR? Simply put, it is the display of digital information that indicates the positions of pipes and cables buried underground over the camera image of a smartphone or tablet. It appears on the screen as if you are seeing through the ground, with images of buried objects appearing. This does not mean that the actual underground is being directly viewed; rather, virtual graphics are displayed based on pre-prepared positional data of “what is where.” From the user’s perspective, however, it feels almost the same as directly confirming underground conditions on site.

There are three major elements required to realize AR visualization of underground utilities.

• Position data of buried utilities: This is the information on underground utilities used as the basis for visualization. Prepare data that shows the routes and depths of water pipes and cables in advance. Existing installation drawings, GIS data, or BIM/CIM models can be used, and for new installations 3D data can be created during the design stage.

• High-accuracy positioning: A system to accurately determine the current position and orientation of the AR-capable device itself. Outdoors, GPS or GNSS (satellite positioning) is used, but ordinary GPS has meter-level errors, so RTK (real-time kinematic) methods are used to secure centimeter-level positioning. In some cases, manual alignment referencing known points on site is performed.

• AR-capable devices and apps: Devices such as smartphones or tablets capable of AR display and applications to display utility data. In recent years, consumer mobile devices have enhanced AR features (camera, gyro, LiDAR sensors, etc.), making it possible to use AR on site without expensive specialized equipment.

With these elements in place, actual usage is simple. First, load the buried utility data into the device’s app and perform positioning of the device. Then, pipes or structures buried underground are displayed as virtual 3D objects or lines over the camera view of the site. For example, “gas pipe at a depth of 1 m (3.3 ft)” or “power cable from here to here” can be drawn on the screen, allowing workers to fine-tune work positions or dig carefully while watching. AR-displayed utilities update in real time according to the viewpoint, enabling understanding of positional relationships from any angle without having to mentally visualize drawings in three dimensions. AR visualization of underground utilities fills on-site information gaps and enables more intuitive and reliable construction decisions.

Why AR visualization can prevent construction mistakes

Visualizing underground utilities with AR directly contributes to preventing various mistakes during construction. Human intuition from “visible” information is extremely important. Compared to imagining pipe positions from drawings, anyone can more accurately grasp positional relationships when blue or red lines appear in AR. So why specifically does AR lead to reduced construction mistakes? Here are the main reasons.

• Eliminates misreading of drawings: AR resolves human errors such as excavating after overlooking drawings or installation markings. Because full-scale pipe positions are shown on AR, workers can intuitively understand safe work areas without constantly referring to paper drawings. Mistakes like misinterpreting scales or misplacing positions on site are less likely.

• Avoids interference with buried utilities in advance: AR visualizes the positional relationship between existing buried utilities and structures to be constructed. For example, if another pipe runs under the proposed excavation area, it is immediately noticeable on the AR screen. By discovering interference risks before construction, design or construction methods can be modified to prevent situations where “excavation uncovers a pipe and work stops.”

• Ensures everyone on site shares the same awareness: AR-displayed information can be shared by everyone present. Points of caution that existed only in the minds of veterans become visible to everyone, including newcomers. Discrepancies such as “I wasn’t told” or “I didn’t know due to communication failure” are reduced, making it easier to align the team and prevent mistakes collectively.

• Real-time feedback: Because the position of underground utilities can be checked with AR while work is in progress, workers can immediately notice if they are getting too close to a hazard. For example, a backhoe operator monitoring pipe positions through a tablet from the cab can make much safer fine adjustments than before. Real-time feedback allows work to progress while avoiding risks as they arise.

In this way, AR can realize “seeing is believing” on site. As a result, human error is greatly reduced, preventing pipe damage and rework due to construction defects.

Improving inspection accuracy by using AR

AR is powerful not only during construction but also for post-construction infrastructure inspections and maintenance work. Because buried utilities are normally not visible, inspections were often carried out by comparing site conditions with drawings and searching while guessing where pipes might run. With AR visualization, inspectors can accurately grasp the locations of buried utilities from above ground, enabling efficient and reliable inspections.

For example, during routine inspections of aging pipes, displaying the water pipe route with AR while searching for leaks allows efficient detection of anomalies. Tasks that previously involved probing with listening rods or metal detectors can be concentrated by following the AR display guide. When searching for buried valves or shut-off valves, visualizing approximate positions with AR can minimize the need for excavation.

AR is also useful for as-built inspections after new construction. By overlaying pre-construction design data and the actual constructed structures in AR, you can confirm on site whether installations match the design. If the position or elevation of installed pipes differs from the design, the deviation is immediately apparent on the AR display. This enables inspections that previously required returning with photos or survey data to be conducted in real time on site.

In addition, the ability to record and share the visual information obtained via AR contributes to improved accuracy. If an inspector captures and saves images of the AR screen they are viewing, the record becomes a “visualized” record that includes the positions of underground pipes not visible in ordinary photos. When reviewing later in the office, the situation can be reproduced more accurately than by simple notes or drawings, improving the precision of reports. When sharing information among stakeholders, AR images and videos reduce the chance of misinterpretation.

Thus, AR supports inspections down to the smallest details, enabling thorough and reliable checks. As a result, the reliability of infrastructure maintenance is enhanced, facilitating early detection and prompt response to problems. Improved inspection accuracy also contributes to longer infrastructure lifespans and reduced maintenance costs.

Key points to keep in mind when introducing AR

While AR visualization offers great benefits, there are several points to be aware of when implementing it on site. To make the most of the technology, keep the following in mind.

• Accuracy management of buried utility data: If the data used for AR display is inaccurate, the whole effort is futile. If only old drawings are available, re-survey as needed and prepare the most accurate position information possible. If new buried utilities are discovered during construction, reflect them in the data for future use.

• Ensuring positioning accuracy: GNSS-based positioning is essential for AR use. Large errors can cause misaligned displays and create hazards. If possible, use RTK-capable receivers, use correction information services, or calibrate on site using known points to maximize positioning accuracy. In areas where GNSS is unstable, such as streets with high-rise buildings, consider using ground-installed target markers for alignment.

• Selection of devices and apps: Consider dustproof/waterproof properties and screen readability when choosing devices for the field. Evaluate high-brightness display tablets that are visible in direct sunlight or hands-free smart glasses depending on the use case. Also check whether the AR app supports the desired data formats and provides sufficient Japanese display and support.

• Training field staff: Effective use of new technology on site requires proficiency. Provide operational training at rollout, and have staff get accustomed through rehearsals and small-scale trials using AR. Although it is intuitive, beginners may be confused at first. Establish rules and procedures with feedback from the field to ensure smooth adoption.

• Integration with existing processes: AR is a support tool and should be used alongside existing safety measures and construction management processes. For example, even when confirming with AR, continue to use trial excavations near important utilities and parallel checks with paper drawings. Avoid overreliance on AR and leverage traditional expertise to achieve robust safety management.

• Cost–benefit considerations: Carefully consider implementation costs and expected benefits. AR-capable devices have become more affordable, and software is increasingly available as inexpensive cloud services. However, implement in a way that matches the scale and frequency of your projects. Start with pilot projects to verify effectiveness before full rollout to avoid unnecessary investment.

By addressing these points, AR technology can be smoothly integrated into field operations and its benefits fully realized. With proper preparation and operation, visualizing underground utilities with AR should become the new norm on construction sites.

Easier AR use with simple surveying using LRTK

Finally, as a technology that makes AR visualization of underground utilities even easier, we introduce “LRTK.” LRTK is a pocket-sized surveying device that can be used by attaching a small high-precision GNSS receiver to a smartphone. Its greatest feature is that anyone on site can perform centimeter-level accuracy (half-inch accuracy) positioning alone, without specialized training or large-scale equipment.

Traditionally, obtaining accurate positions of buried utilities required surveying with a total station and other equipment. With LRTK, however, simply holding up a smartphone and pressing a button allows you to measure and record coordinates of buried utilities on the spot. For example, after burying a pipe, measuring several points with LRTK can digitize the pipe route with high accuracy. Sharing that data immediately via the cloud and importing it into an AR app enables accurate visualization of the pipe location from the moment construction is completed. LRTK lowers the barrier to surveying work, dramatically streamlining the data preparation needed for AR use.

LRTK not only measures positions but is also designed with AR integration in mind. By placing virtual objects at coordinates obtained with LRTK within an AR app on a smartphone, you can visualize stake positions or buried routes on the spot. LRTK is literally the bridge that connects measuring (reality) and showing (virtual).

Using such simple surveying tools makes high-precision data acquisition, which previously relied entirely on surveying specialists, something that site teams can perform. As a result, digital construction, including AR visualization of underground utilities, will become increasingly commonplace. LRTK is a powerful ally supporting an AR-based construction revolution. By adopting cutting-edge technologies wisely, let’s realize safer and more efficient construction sites.

FAQ

Q: Can AR really let you see beneath the ground? A: AR does not directly show the actual underground like an X‑ray imaging camera. It displays virtual information based on pre-obtained position data. However, if the data is accurate, it can feel as if the ground is transparent. The key is that AR is a technology that “shows” rather than “sees,” but from the on-site perspective it sufficiently visualizes underground conditions.

Q: Do I need special equipment or expertise to use AR? A: All you need are an AR-capable smartphone or tablet, a compatible app, and buried utility data. Recent smartphones come standard with AR capabilities, so you can get started without expensive specialized equipment. If you want higher accuracy, you can connect a GNSS receiver to your smartphone to achieve centimeter-level positioning. The operation itself is intuitive—just point the camera—so advanced IT skills are not required. With simple training, field staff can use it effectively.

Q: How do you prepare position information for underground utilities? A: For existing infrastructure, the first step is to obtain piping and installation drawings from relevant agencies. Since old drawings can be inaccurate, confirm actual positions as needed with ground-penetrating radar or trial excavations and correct the data. For new installations, create 3D information during the design stage. Using a simple surveying system like LRTK to measure on site and obtain high-precision coordinates is recommended. Once digitized, manage position information in GIS or the cloud and keep it up to date.

Q: How much does it cost to introduce AR? A: Costs vary by scale and method, but it is much more affordable than before. Dedicated AR hardware used to be expensive, but today you can use commercial smartphones and tablets to reduce hardware costs. GNSS receivers for improved accuracy are also becoming more affordable than conventional surveying equipment. Software is frequently available as subscription services at accessible price points. Considering the costs saved by preventing construction mistakes and improving efficiency (such as rework and accident response costs), the return on investment can be substantial.

Q: What is LRTK? A: LRTK is a GNSS solution that turns a smartphone into a high-precision surveying instrument. It consists of a pocket-sized device and a dedicated app, enabling anyone to easily obtain centimeter-level accuracy (half-inch accuracy) position information. It is an evolution of RTK‑GNSS technology made more user-friendly, and it supports on-site surveying as well as cloud sharing of acquired data and use in AR displays. It is attracting attention as a tool to streamline locating underground utilities and as-built management.