AR-guided Efficiency for Distribution Equipment Construction: Field Innovation Enabled by High-Precision Positioning

The Need for Labor Saving and the Importance of Construction Accuracy in Distribution Equipment Work

On worksites for distribution equipment—the backbone of power infrastructure—the need for labor saving has been growing in recent years. This is due to the aging of skilled workers and labor shortages, which require that tasks be carried out efficiently with small crews. In addition, construction accuracy is critical when installing or upgrading distribution lines. For example, if the position of a utility pole shifts by just a few dozen centimeters, it can disturb the tension balance of the lines and the required clearance from surrounding equipment, potentially causing rework. Power companies must complete installations correctly the first time to avoid rework and equipment defects. This is where high-precision positioning technology combined with AR (augmented reality) for onsite support has attracted attention. By overlaying digital data onto the field with centimeter-level accuracy, tasks that used to rely on craftsmen’s intuition and experience are being transformed into data-driven smart construction. If design information can be projected onto the site with high positioning accuracy, even slight deviations can be detected and corrected on the spot, directly improving construction accuracy and preventing rework. As a solution that achieves both labor saving and improved accuracy, AR-guided construction is enabling a revolution in distribution work.

Surveying and Layout Challenges for Overhead and Undergrounding Works

Distribution equipment work includes overhead distribution line construction, which handles poles and lines, and undergrounding work (pole elimination) that buries cables underground. In these sites, pre-construction surveying and the layout marking (setting-out) of structures are crucial processes that determine construction accuracy. However, traditional methods have many challenges.

In overhead work, it is necessary to determine the precise position and height of newly installed poles. Typically, a surveying team uses coordinates from the drawings to drive stakes or mark the site, but this process consumes manpower and time. The routine of measuring points with a total station → comparing with drawings → marking on-site is cumbersome and requires repeatedly cross-checking plans to derive positions. In urban areas, work must be carried out with consideration for traffic and the surrounding environment, so it is required to finish layout marking quickly and accurately. Human-led work is prone to human error, and even minor measurement mistakes can disrupt later processes.

In undergrounding work, when burying power cables beneath roads, it’s necessary to accurately understand the positional relationships with other existing infrastructure such as gas pipes and water/sewer lines. Even if you check as-built drawings beforehand and mark the site, it is not uncommon for the information on the drawings to diverge from the actual conditions after years of renovations. In urban areas, underground piping is often densely congested, and there are frequent near-miss incidents where unexpected existing cables appear where they were not expected. Traditionally, veteran workers relied on experience and intuition—cautiously digging where they thought a specific pipe might be buried—but it was difficult to completely prevent mistakes. Ground-penetrating radar and trial excavations also have limits, making how to make the unseen visible a fundamental challenge in underground installation work.

Thus, in both overhead and undergrounding settings, accurate surveying and layout marking require significant effort and advanced skills, and achieving both efficiency and accuracy amid labor shortages has been a major issue.

How High-Precision GNSS (RTK) and AR Display Provide Position Guidance

One solution to these challenges is the technology of combining high-precision GNSS positioning with AR displays for position guidance. Traditional smartphone AR relies on built-in GPS, which often produces errors of several meters in alignment. That level of error is unusable for positioning poles or cables and required cumbersome manual adjustments such as placing markers on-site for calibration. For wide-area distribution line projects, placing markers and calibrating at each location is impractical and undermines the convenience of AR. However, by combining GNSS with RTK (Real-Time Kinematic) corrections, positioning errors can be reduced to a few centimeters, enabling AR alignment on-site with virtually no error. RTK applies real-time correction information from base stations to improve positioning accuracy, achieving centimeter-level accuracy both horizontally and vertically.

Recent smartphones also include advanced AR platforms and sensors: camera images combined with IMU (inertial measurement unit) data capture device movement, and high-end models even include built-in LiDAR (light detection and ranging) scanners. LiDAR enables capturing the surrounding environment as three-dimensional point cloud data in real time, allowing virtual objects (such as design models of poles or cables) to be stably overlaid on the real world and enabling occlusion handling so parts hidden behind obstacles are not shown. Combining this smartphone AR spatial recognition technology with RTK positioning that determines the device’s position to the centimeter level forms an approach called markerless high-precision AR. For example, if you preload 3D design data for pole positions or cable routes into the device, simply pointing the smartphone at the site will display the virtual model virtually exactly where it was designed to be. Virtual overlays that used to be off by meters can literally be reduced to “errors of just a few centimeters,” making AR guidance practically usable on-site for the first time.

Specific Examples of AR Construction Support with a Smartphone + Compact RTK Receiver (Pole Installation, Cable Routing, Junction Box Installation)

A high-precision AR system that combines a smartphone with a compact RTK-GNSS receiver is powerful across many construction scenarios in distribution work. Here are examples for pole installation, cable route laying, and junction box installation to illustrate applicable use cases.

• Guiding and verifying pole locations: For new pole installation, stakes are driven and holes excavated at positions specified in the design. AR construction support can display virtual pole models or markers on the smartphone screen to guide workers to the designated position. For example, as a worker walks the site holding a smartphone, an AR marker indicating the pole installation spot appears on the screen, guiding them like an AR navigator to the target location. Tasks that used to require two people measuring distance and angles can now be done by one person holding a pole-mounted device with a smartphone + RTK, following the on-screen guidance to mark the exact position. After excavation and pole setting, the virtual pole model overlaid on the real structure via smartphone AR allows immediate verification that the pole is in the designed position and plumb. Slight tilts or offsets can be detected on the spot and corrected before concrete cures, preventing construction errors.

• AR visualization of cable routes: AR is also useful for stringing overhead distribution lines and for setting cable routes in undergrounding projects. If the designed cable route is modeled in 3D in advance, a virtual cable suspended in the air can be rendered between poles through the smartphone. This lets teams visually confirm the planned stringing route and clearances in advance, checking for interference with trees or buildings and verifying heights at road crossings. For instance, it becomes immediately apparent that “if the cable runs at this height, there will be ○m of clearance above the sidewalk,” enabling rapid consideration of design changes if necessary. In undergrounding work, AR can display the excavation route for new cable conduits on the road surface. Before digging begins, pointing a smartphone at the road shows a virtual line indicating the trench’s position, width, and direction, allowing operators to excavate along the virtual line to achieve the planned route. Points where underground utilities must be avoided can also be highlighted in AR and shared, so all workers intuitively understand where to take care. As a result, survey personnel don’t need to be present for every action, and onsite workers can proceed accurately on their own, reducing labor and shortening task time.

• Improving accuracy for junction box installation: In pole-eliminated distribution networks, installing junction boxes (handholes and aboveground equipment) that connect buried cables is essential. AR guidance is also effective for positioning and height alignment of these installations. For example, when installing aboveground equipment beside a sidewalk, a life-sized virtual model can be displayed in smartphone AR to check compatibility with the surroundings while guiding workers to the precise installation point. Distances from road boundaries and other equipment are visualized on the screen, enabling placement that maintains required clearances. Because you can check space and visibility with a virtual model before moving the actual equipment, issues such as “it turned out to be more obstructive than expected” or “the inspection hatch is hard to access” can be identified in advance. For buried handhole installations, AR can indicate the lid level so that it sits flush with pavement, or show the connection angles to existing conduits in 3D. After installation, overlaying the design model on the camera view makes it easy to verify on the spot that the box is within the design coordinates, reducing the risk of re-excavation due to placement errors.

As described above, smartphone + RTK AR construction support serves as a visible guide in all phases of distribution equipment work, enabling less experienced workers to perform precise construction without relying on intuition.

Construction Errors Preventable by AR Guidance and Efficiency Gains (Time Savings, Reduced Dependence on Skilled Workers)

The benefits of AR-guided construction go beyond specific task support. There are reported effects directly linked to overall error reduction and efficiency improvements on site.

First, error prevention. Working with design models overlaid on real structures in AR lets workers detect and correct slight position deviations and construction mistakes on the spot. For example, if a pole foundation is offset from the design by several centimeters, the discrepancy is visualized in the AR view, allowing immediate correction. This leads to fewer quality defects and less rework, significantly reducing the risk of post-completion issues. In the past, defects might only be flagged during final inspections, necessitating rework, but with AR guidance encouraging a culture of “correct it on the spot,” unnecessary redo work can be avoided.

Next, improved work efficiency. AR guidance can consolidate multiple processes—surveying, layout marking, and inspection—into a single smartphone workflow. Eliminating the need to hold drawings and estimate positions by intuition reduces wasted movement and enables crews to perform only the tasks required at precise locations. This results in shorter work times and labor savings, allowing small teams to proceed smoothly. On sites where a single smartphone handled surveying, stake driving, and as-built recording, reductions in manpower, shortened schedules, and cost savings have been observed.

Moreover, reduced dependence on experienced workers is a major advantage. Tasks that once depended on the instincts of veteran workers are becoming accurate operations anyone can perform with the help of data and AR. By making the site conditions and design intent a shared language via AR, younger staff or newcomers can make appropriate decisions. For example, complex underground wiring plans become less error-prone when visible AR information is shared across the team, reducing miscommunication. Without relying solely on veterans’ verbal instructions or craft techniques, everyone can perform construction while looking at the same “correct answer,” which helps standardize work quality. As a result, safety improves (reducing miswiring or excavation accidents) and productivity can leap forward, making this approach a promising measure against chronic workforce shortages.

As-built Verification and Inspection Records: Smartphone, Point Cloud, and Cloud Integration

High-precision AR guidance contributes not only during construction but also to post-construction as-built verification and future inspection records. By using a smartphone’s LiDAR scanning and RTK positioning, it is possible to accurately record structures in 3D immediately after construction and manage that data in the cloud.

For example, in an undergrounding project where conduit was installed, scanning the conduit and excavation area with a LiDAR-equipped smartphone before backfilling can digitally preserve the exact route, depth, and shape of the installed conduit. Point cloud data acquired with an RTK receiver attached to the phone is automatically tagged with high-precision world coordinates and uploaded to the cloud. The system can automatically generate 3D models (meshes) of the conduit sections from the point cloud, removing the need to take measurements and produce drawings or paint markings on the road after backfilling. Just scanning completes a detailed 3D as-built record, preserving installation positions in millimeter-scale precision that paper as-built drawings cannot convey.

These as-built data can be immediately shared and managed via the cloud. Point clouds and generated models scanned on-site are accessible from office PCs or other devices, and can be imported into asset management ledgers or GIS systems for long-term storage. The cloud enables one-click analyses of point cloud data—measuring depths and dimensions on arbitrary cross-sections or automatically calculating excavation and backfill volumes—so supervisors and construction managers can obtain necessary numerical information without redrafting CAD drawings or manual calculations. Cloud sharing also allows off-site personnel to review the point cloud model and provide instructions. Even when not on site, supervisors can verify as-built conditions in real time and give appropriate advice such as “backfill slightly more here,” enabling the organization to elevate construction quality collectively.

Accumulated 3D as-built data are also powerful for future inspection work. Instead of digging up paper drawings during annual inspections or equipment replacements, teams can display the cloud 3D model in AR for on-site confirmation. For example, if you re-excavate the same location years later, displaying the scanned conduit position in smartphone AR reveals what is buried at what depth at a glance. Without needing to interpret drawings, anyone can immediately understand past buried conditions and plan accurate digging regardless of experience. For equipment replacement planning, overlaying past repair history onto current point cloud data in AR helps identify which sections to replace and assess degradation on the spot. By enabling preventive maintenance based on data, organizations can plan replacements with margin and prevent accidents. In this way, integrating smartphone scanning, point clouds, and cloud-based data management seamlessly connects as-built verification through maintenance. Because information does not degrade over time and high-precision spatial coordinates remain available, improvements in accuracy and efficiency can be expected across the life cycle of distribution infrastructure.

Implementation Example of Smartphone RTK + AR Guidance + Point Cloud Management: Field Innovation with LRTK

Finally, as a concrete solution that realizes the high-precision positioning, AR guidance, and point cloud management described above, we introduce a system called LRTK. LRTK is a smartphone GNSS high-precision platform developed by Lefixea, a startup originating from Tokyo Institute of Technology, and consists of a compact RTK-GNSS receiver and a dedicated app. When the receiver—weighing several hundred grams and attached to the back of a smartphone—is powered on, RTK satellite acquisition is completed in just tens of seconds, allowing centimeter-level AR displays to begin immediately without troublesome initial calibration. Unlike conventional AR surveying tools, there is no need to place markers or perform coordinate alignment adjustments for each site; simply starting the device enables high-precision spatial overlays. LRTK also includes cloud integration features, allowing design data and point cloud survey data to be downloaded to the device for AR display or uploading field-acquired data for immediate sharing. It is designed to be intuitive for non-expert workers, and there are reports that one smartphone per person covered surveying, layout marking, inspection, photo records, and AR simulation on actual sites.

By using LRTK, it becomes possible to dramatically improve field productivity and safety without costly surveying equipment or large teams. Applications include transparent visualization of underground utilities, as-built verification of structures, and real-time construction navigation, making it a true “all-purpose surveying tool” and a trump card for on-site DX. It aligns with the construction industry’s digitalization trends led by the Ministry of Land, Infrastructure, Transport and Tourism's *i-Construction*, and the adoption of smartphone RTK + AR in distribution equipment work represents a major step toward DX. Power companies and contractors can bring their sites to the next level by adopting these advanced technologies. The LRTK official site publishes case studies in solar panel installation and civil infrastructure inspection, and suggests applications to distribution line work as well. If interested, please refer to the [LRTK official site](https://www.lrtk.lefixea.com/) for hints on field innovation. The day when advanced positioning technology and AR-enabled visible construction rewrite the norms of distribution equipment construction is just around the corner.