Table of Contents

• Introduction: Underground Utilities and the Potential of AR

• Common Challenges in Underground Utility Works

• How AR Sees Through Underground Utilities and Its Benefits

• Using AR to Approach Zero Construction Errors

• Why Inspection Accuracy Improves

• On-Site Introduction of AR Technology and Necessary Preparations

• Simple Surveying Techniques That Support High-Accuracy AR

• Easy AR Adoption with LRTK Simple Surveying

• FAQ

Introduction: Underground Utilities and the Potential of AR

Beneath roads and sites lie countless underground utilities such as water pipes, gas pipes, and power cables. These are vital components supporting urban infrastructure, but because they are hidden underground it is difficult to accurately grasp their positions during construction, which can lead to construction mistakes and accidents. Recently, solutions that use AR (augmented reality) technology to let you simply hold up a smartphone or tablet and seemingly “see through” the ground to view buried utilities have been attracting attention. If AR can visualize the locations of underground pipes and cables, it can ease concerns like “what is buried here?” and is expected to bring us closer to zero construction errors. In addition, during post-construction inspections, AR can improve accuracy compared to traditional methods that rely on drawings and intuition, enabling quality control that even designers and supervisors will accept. This article explains the current state of technology that allows “seeing through underground utilities with AR” and why its effects can eliminate construction errors and improve inspection accuracy.

Common Challenges in Underground Utility Works

In works involving underground utilities, there are frequent human errors such as accidentally damaging existing pipes during excavation or installing pipes in positions that differ from the design. For example, accidental damage to water or gas pipes can lead to major troubles like significant construction delays or service interruptions in surrounding areas. Because the underground situation is invisible, construction personnel must proceed carefully relying on design drawings and past burial records, but if old drawings are inaccurate or memories of locations are unclear, there is always uncertainty until excavation reveals the actual situation. Under these circumstances, workers must be cautious, which can lead to reduced construction efficiency.

Furthermore, after burying utilities, backfilling must be done, but prior to that it is necessary to perform surveying and photography for records. Traditionally, at completion workers would measure pipe positions and depths with a tape measure and note them on paper, or photograph excavation sites, and later create drawings based on that information—a time-consuming process. If records are insufficient, the exact positions may be lost later, and when someone digs nearby in the future the problem of unknown locations of buried utilities can arise. In short, underground utility works always carry the risk of being “invisible,” and that has been the root cause of construction mistakes, inefficiencies, and record deficiencies.

How AR Sees Through Underground Utilities and Its Benefits

To solve these challenges, solutions using AR (augmented reality) to visualize the positions of underground utilities have emerged. Concretely, when you view the site through the camera of a smartphone or tablet, 3D models or positional information of buried pipes and cables are overlaid on the screen. It appears as if you are using special X-ray goggles to look beneath the ground—the virtual utility models emerge over the real landscape.

To realize this AR see-through, you need both accurate positional data of the underground utilities and technology to accurately determine the user’s current position on site. For the former, existing buried pipes can be modeled in 3D based on GIS or drawing data, and newly installed pipes can be modeled from design data or scan data acquired during construction. For the latter, satellite positioning like GPS or GNSS, or surveying using site control points capture the device’s position and orientation. The latest systems combine small high-precision GNSS receivers attached to smartphones with the phone’s built-in sensors to enable highly accurate alignment within a few centimeters (a few in). As a result, AR displays of utilities are overlaid almost exactly where they are in reality, allowing intuitive judgments like “if we dig here, we’ll hit the pipe right under this spot.”

The benefits of AR see-through are clear. First is improved safety. Knowing the positions of underground obstacles in advance with AR greatly reduces the risk of accidentally damaging pipes. Also notable is the reduction of workers’ anxiety. Eliminating the unease of working over unseen ground allows workers to proceed calmly and efficiently. Furthermore, smoother communication is another benefit. Instead of a site supervisor or designer saying “be careful around here, there should be a pipe” verbally or via drawings, they can share the AR screen on site and point out “you can see the pipe here,” eliminating mismatched understanding. In these ways, AR visualization directly contributes to safe and secure construction.

Using AR to Approach Zero Construction Errors

Why can the use of AR see-through bring us closer to zero construction errors? There are two main reasons.

The first is that AR can prevent damage accidents to buried utilities. As noted above, even when workers excavate cautiously based on experience and drawings, misunderstandings or measurement mistakes due to invisibility can lead to damage to other pipes. But if you know the positions of utilities via AR, you can accurately grasp distances and depths such as “excavate this many meters and you’ll reach the pipe,” which drastically reduces human errors like over-excavating or hitting with a machine bucket. Damage to underground utilities is one of the most serious construction mistakes, and by using AR to nearly eliminate such incidents you can make a substantial step toward literal “zero construction errors.”

The second is that AR encourages construction that follows the design. In underground utility works, pipe routes and depths are designed in advance, but site conditions may require minor adjustments, and variability in construction accuracy can result in pipes being buried away from their intended locations. Traditionally, once backfilled and the surface restored, it was not easy to confirm whether pipes were installed correctly. However, by using AR during construction, workers can visualize the design model (or guideline lines based on design values) on site and constantly compare their work to the ideal. For example, if you check on AR whether “the pipe slope matches the design” while installing, accuracy improves dramatically compared to relying on intuition. Because the constructor can see the correct answer in real time, rework and redoing are prevented and quality assurance is achieved. Designers will also be reassured when they can immediately see their designs realized in the field. AR see-through provides scientific backing to parts of site work that used to depend on “feel and experience,” contributing to the eradication of construction mistakes.

Why Inspection Accuracy Improves

AR see-through technology also proves highly effective in the post-construction inspection and testing phase. Traditionally, because completed underground utilities cannot be directly inspected visually, inspectors relied on drawings and record photos to infer positions and sometimes performed trial excavations to verify. This consumes time and risks oversights and measurement errors due to incorrect assumptions about pipe locations.

With AR, inspectors or supervisors can simply hold up a smartphone on the completed site and confirm the positions of buried utilities on the screen. For example, they can check whether “the hydrant piping is buried in the correct position as per the design” by comparing the AR-displayed model to the current situation. If the construction result deviates from the design, the discrepancy is immediately obvious on AR. If depth information is included in the AR display, vertical errors can also be detected by comparing with measured values from the surface. In other words, AR enables intuitive and accurate verification that is superior to the traditional method of mentally matching drawings to the site.

Moreover, improved inspection accuracy is supported by enhanced data recording. The data prepared for AR see-through (3D scans, point cloud data obtained during construction, etc.) become high-accuracy record materials. Inspectors can reference these to verify details that paper records cannot capture. For example, a 3D model generated from point cloud data allows detailed inspection of pipe diameters and joint conditions and, if necessary, measurement of dimensions. Inspections based on such digital records reduce omissions and the chance of human error, thereby improving the reliability of inspection work. For designers and owners, being able to confirm both via data and AR visuals that a facility is accurately built and safe to operate provides solid assurance.

On-Site Introduction of AR Technology and Necessary Preparations

The idea of seeing through underground utilities with AR is very appealing, but there are several challenges to overcome when actually introducing it on site. First, you must prepare digital data of the underground utilities as a prerequisite. If existing infrastructure positional information is not digitized, you need to acquire position information from past drawings or measurement by detection equipment and organize it into a database. For new installations, generate data by preparing 3D models at the design stage or by scanning and recording positions during construction. In any case, having accurate three-dimensional information to display in AR is the essential prerequisite.

Next is the preparation of equipment and environment for using AR on site. In the past, AR see-through required dedicated AR goggles or high-performance PCs, but today smartphones and tablets are sufficiently practical. Recent smartphones have excellent cameras and sensors, and models equipped with LiDAR scanners can even capture 3D point clouds on the spot. However, to achieve stable, high-accuracy AR outdoors across a wide site, a smartphone’s standalone GPS typically has too large an error, so devices that assist high-precision positioning are helpful. For example, attaching a smartphone-compatible RTK-GNSS receiver and using correction information from a base station can determine the current position with positioning errors on the order of a few centimeters (a few in). Cloud services that integrate with smartphones are also important. By storing and managing underground utility data and scans acquired on site in the cloud, you can download them on-site for AR display and share the latest information in real time among stakeholders. If data can be checked and edited in the cloud and immediately reflected in the field AR view, remote designers can understand site conditions from the office and issue instructions.

At introduction, there is also concern about personnel training. However, recent AR solutions have intuitive user interfaces, and there are growing examples where site workers can use them without pre-training. If AR spreads as a tool that anyone can use rather than being left to specialists, it will become part of daily work. The keys are “simplicity” and “integration into everyday workflows.” In that sense, AR see-through that can be completed on familiar devices like smartphones is expected to penetrate the field.

Simple Surveying Techniques That Support High-Accuracy AR

Behind the success of AR see-through for underground utilities is the advancement of surveying techniques that support accurate data acquisition and alignment. Particularly important are simple surveying methods that allow easy high-accuracy position measurement on site. Traditionally, surveying was performed by specialists using expensive total stations or GNSS equipment, and was not something general construction staff could readily handle. But with digital technology advances, it is becoming possible for anyone to achieve centimeter-level (half-inch-level) positioning using smartphones and small devices.

For example, GNSS receivers that link to smartphones or photogrammetry techniques using special markers have emerged to simplify site staking and measurement. These solutions are designed to be usable without specialized knowledge, and feature one-touch acquisition of control point coordinates or on-the-spot distance measurements between points. Using these simple surveying techniques, position information of buried utilities can be quickly measured and recorded during site work. As a result, the data necessary for later AR display can be left completely and accurately.

Also, acquired surveying data can be uploaded to the cloud immediately and accumulated as a digital ledger. Rather than relying on paper drawings or handwritten notes, the high-accuracy positions of utilities plotted on a cloud map become an asset useful for future maintenance or other construction. In this way, simple on-site surveying technologies are the unsung but essential support behind AR see-through.

Easy AR Adoption with LRTK Simple Surveying

Finally, as a concrete solution to make AR adoption even more approachable on site, we introduce simple surveying using LRTK. LRTK is a system that attaches a compact high-precision GNSS unit to a smartphone so a single worker can perform centimeter-level (half-inch-level) positioning and 3D scanning. On utility construction sites, if you scan buried utilities with an LRTK-equipped smartphone and upload the data to the cloud, information such as pipe shape and burial depth is automatically recorded as point cloud data with global coordinates. From that data a 3D model can be generated, so even after backfilling you can perform real-time see-through of underground pipes through a smartphone screen. Because measurement to AR display can be completed on site without specialized BIM modeling work, this enables everyday AR usage—so-called “AR for everyday use.”

High-precision data obtained by LRTK can be shared and utilized in the cloud. For example, office engineers can view point cloud data in the cloud to measure necessary dimensions or compute the volume of soil required for backfilling with a single click. Immediate digitization and visualization of field-collected information smooths coordination between the site and the office, eliminating unnecessary rework and information transmission errors.

Above all, LRTK’s strength is its ease of use by on-site personnel. With an intuitive smartphone app, it can be used without complex settings or special training, so workers who are not ICT-savvy can adopt it with little resistance. In practice, there are reports of sites where staff began using it without prior training and immediately found it helpful for work. New technologies prove their worth when they integrate into the toolbox of the site. LRTK simple surveying helps embed the cutting-edge AR see-through into daily operations and strongly supports the goals of zero construction errors and improved inspection accuracy.

FAQ

Q1. What is required to display underground utilities in AR? A1. Basically, you need 3D data that includes positional information of the underground utilities and an AR-capable device to display it. Specifically, utility 3D models or point cloud data, a smartphone or tablet, and ideally a GNSS receiver capable of high-precision positioning are required. Although modern smartphones alone can provide AR displays, use of RTK-GNSS equipment is increasingly common to minimize positional offsets.

Q2. What types of underground utilities can AR see-through be used for? A2. It can be used for virtually any underground infrastructure: water pipes, sewer pipes, gas pipes, communication cables, power cables, etc. Not only metal pipes but also resin pipes and cable conduits can be visualized on AR as long as their buried positions are known. Beyond buried utilities, it can also be applied to inspection of underground foundations, pits, tanks, and other structures. The strength of AR see-through is that anything whose position and shape are known can be displayed as a virtual model.

Q3. How accurate is AR see-through display? A3. Accuracy depends on the system configuration, but the latest AR systems using high-precision GNSS can reproduce utility positions with errors on the order of a few centimeters (a few in). For example, smartphone AR using RTK-GNSS corrections like LRTK places models based on accurate global coordinates, so the positioning is nearly identical to reality. However, small offsets can occur due to sensor calibration or the surrounding environment (such as satellite signal reception conditions). Even so, displaying unseen objects with an error of a few centimeters is practically sufficient for field work.

Q4. I’m worried about on-site introduction costs—are expensive devices necessary? A4. While dedicated AR glasses or professional surveying instruments can be costly, solutions that use smartphones or tablets can be introduced at relatively low cost. If you already use tablets on site, adding AR functionality is a natural extension and not a high hurdle. Peripheral devices like GNSS receivers are becoming compact and affordable. For example, smartphone-mounted RTK-GNSS units like LRTK are offered at price points far easier to introduce than traditional large surveying instruments. Cloud services are also commonly provided on a subscription basis, allowing you to limit initial investment and use the service only for necessary periods.

Q5. What precautions should be taken when using AR see-through on site? A5. First, ensure the accuracy and currency of the information displayed in AR. Using outdated data or inaccurate drawings for AR display can mislead users if the displayed positions differ from reality. Always prepare reliable data and update it when necessary. Also, because users look at the surrounding area through a device screen, take care not to neglect actual footing and safety checks. There is a non-zero risk of tripping or failing to notice obstacles if users focus too much on AR, so balance AR use with safety management. If those precautions are observed, AR see-through becomes a powerful support tool for on-site work.