Utilizing AR × High-Precision Positioning for Distribution Equipment Inspections: Achieving Labor Savings in Inspection Tasks with Smartphones

Conventional Challenges in Distribution Equipment Inspections

Inspections of power company distribution equipment (utility poles, transformers, switchgear, cables, etc.) are critical tasks that support stable power supply. Typically, inspectors patrol an area and visually check the exterior of utility poles and transformers to detect abnormalities. Tasks also include observing high-elevation equipment with binoculars and, when necessary, measuring values such as ground resistance. However, there are limits to working at height in harsh environments and to manually recording tasks; several issues regarding efficiency and accuracy have been pointed out. Major problems include the following:

• Dependence on individual expertise: Inspection know-how tends to rely on the experience of skilled workers and depends on personal intuition and tacit knowledge. There are concerns that maintaining quality becomes difficult when veterans are transferred or retire.

• Reliance on drawings and documents: On site, workers confirm equipment while referring to paper drawings and asset ledgers, but old drawings may not reflect updates and can differ from the actual situation. Especially in urban areas with frequent modifications, discrepancies between drawing information and field reality are not uncommon, sometimes forcing workers to rely on intuition.

• Complexity of inspection records: Inspection results are mainly recorded manually, following a flow of taking photos → making notes → organizing them into reports later. Correlating photos and notes to link locations and contents is cumbersome and risks entry errors or missing information. There is also the possibility of losing field notes or misreading them, which adds unnecessary effort to report creation.

• Effort and risk of safety checks: For work at height or inspections around live lines, thorough safety checks are indispensable. The process of multiple people pointing and calling out to check off a checklist imposes a heavy burden on site, and human error such as misidentifying equipment can lead to serious accidents. Completely eliminating human mistakes is difficult, and the risk of accidents is ever-present.

These issues indicate that there is room to improve not only efficiency in distribution equipment inspections but also the consistency of work quality and safety. In fact, there have been instances where oversights or reporting mistakes by less experienced personnel nearly caused trouble. Traditionally, this field had to rely on veterans' knowledge and manual work, but recently there has been a movement to introduce digital technologies on site. Against this backdrop, the power industry is accelerating efforts toward DX (digital transformation) for inspection and maintenance work. One particularly noteworthy approach is the next-generation inspection method combining AR (augmented reality) technology and high-precision positioning (RTK).

Precise visual assistance through the fusion of AR technology and RTK high-precision positioning

AR (Augmented Reality) overlays digital information—such as CG models and text—onto real-world images seen through a camera. RTK (Real Time Kinematic) positioning is a high-precision positioning method using GNSS (satellite positioning) that can determine locations with centimeter-level accuracy. RTK requires a base station that transmits correction signals, but recently networked RTK services that use infrastructures like the Geospatial Information Authority of Japan’s electronic reference station network have been developed nationwide, enabling mobile receivers to obtain correction data via communication networks. Because it is not necessary to install a dedicated base station on site, environments where centimeter-level positioning can be performed with a small receiver and a smartphone are becoming available. That said, high-precision positioning needs open skies to receive satellite signals well. Positioning accuracy may degrade in areas with high-rise buildings or dense trees, but Japan also offers the quasi-zenith satellite "Michibiki" and its CLAS (Centimeter-Level Augmentation Service), which can provide correction information directly from satellites even outside communication coverage; combining these technologies can achieve stable centimeter-level positioning. By combining AR and RTK, distribution equipment inspections can achieve both high positional accuracy and intuitive visual clarity at the same time.

For example, when a smartphone camera is pointed at a utility pole, the screen could display tags showing the names of devices installed on that pole and the inspection items. For buried distribution cables, pre-measured and registered route data can be visualized on the ground via AR, allowing operators to "see through" the ground to locate invisible cables when excavation is required. Past inspection histories and specification details from design drawings can also be displayed on the AR screen, enabling immediate onsite reference to information such as "this transformer was manufactured in 20XX" or "this switch was replaced ○ years ago."

However, accurately overlaying digital information onto real space requires highly precise alignment. Ordinary smartphone GPS can have errors of several meters, causing AR-rendered virtual equipment models to be significantly offset from their real positions and rendering the system impractical. Conventional AR systems often required placing markers (registration markers) at each site or manually adjusting model positions at the start. For widely distributed networks like distribution grids, placing and calibrating markers at every location is unrealistic.

This is where centimeter-level positioning with RTK is powerful. By combining a smartphone with an RTK-capable compact GNSS receiver, you can obtain highly accurate absolute coordinates of the current location. Feeding this into an AR app allows digital information displayed on the smartphone screen to be overlaid on real objects with negligible offset. In other words, markerless yet high-precision AR display becomes possible, and the positional discrepancy between virtual information seen through the camera and the actual object is nearly eliminated. Because operators can follow AR-displayed instructions to reliably interact with the correct equipment, this also helps reduce the risk of accidents due to human error, such as misoperation of switchgear.

Moreover, recent smartphones have begun to include LiDAR (light detection and ranging) sensors. LiDAR can instantly capture distances and shapes of surrounding structures, enabling AR objects to be stably rendered according to the environment and allowing accurate occlusion representation when objects are partially hidden. Combining RTK’s high-precision positioning with smartphone AR platforms and sensor technologies makes it possible to provide unprecedentedly precise and intuitive operational support even in distribution equipment inspection sites.

Intuitive inspections with smartphones and automated recording

Leveraging AR × high-precision positioning does not require large specialized equipment or complicated operations. Recently, compact RTK-GNSS receivers that pair with smartphones have become available, making high-precision positioning easier to use. Field inspectors can perform work using the single smartphone they always carry, intuitively obtaining information while working and simultaneously recording data.

For example, an inspector can hold a smartphone in one hand, launch a dedicated app, and simply point it at equipment. The camera image will overlay a visual indicator of the "next item to inspect." If the top of a pole is shown, arrows can point to deterioration-prone parts (insulators, fittings, etc.) and inspection items are displayed as text. Confirming and photographing according to the instructions causes photos to be automatically saved with associated coordinates and timestamps. There is no longer a need to later figure out which equipment or which part of the equipment a photo corresponds to.

Notes and observations can also be completed on the smartphone. Checklists can be filled out and voice comments recorded on the spot, eliminating the need to carry a paper notebook home. Furthermore, LiDAR-equipped smartphones can scan areas of interest to capture 3D point cloud data. For instance, capturing point clouds of a pole or fittings allows detailed dimensional analysis back at the office.

In this way, with a smartphone and AR app, photography, notes, and point cloud measurements are performed seamlessly and automatically recorded digitally. All data collected on site are linked to timestamps and high-precision position information, greatly reducing the time spent organizing photos or transcribing into reports after inspections. In fact, there are reported cases where a single smartphone per person covered everything from surveying (positioning) to inspection, recording, and AR-based completion checks, showing that an inspection workflow that can be completed with a small team and in a short time is becoming a reality without the need for specialized equipment or large teams.

Updating digital ledgers and remote reporting via GIS and cloud integration

Conventionally, field notes and photos taken on site were brought back and manually entered into ledger systems, causing time lags in data updates and risking entry errors. With inspections using AR × RTK, inspection data collected on site with a smartphone can be linked immediately to GIS or cloud-based digital ledger systems.

Specifically, inspection data recorded with a smartphone (photos, coordinates, inspection comments, etc.) can be uploaded to internal servers via the cloud in real time and shared with relevant departments. This allows the inspected content to be reflected in internal systems in real time, enabling staff to grasp the latest inspection status from the office.

Key effects of digital integration include:

• Streamlined reporting tasks: Inspection information is automatically compiled into electronic reports, reducing later form creation and transcription work. Photos and comments with location data are recorded as-is, removing the need to add positions or conditions when preparing reports.

• Real-time sharing and remote support: Cloud-based sharing makes it easy to share information between the field and the office, allowing inspection status to be checked and instructions issued from remote locations. In emergencies, headquarters can quickly consider countermeasures based on photos and detailed information sent from the field.

• Centralized data management: Photos, notes, and location information are accumulated directly in the digital ledger, preventing information omissions or reporting delays associated with paper records. Past data can be traced on maps during personnel changes, reducing the risk of information loss during handovers.

• Utilization of accumulated data: Accumulated inspection data can be visualized on GIS maps, making it easy to analyze the distribution and trends of abnormal occurrences. For example, overlaying inspection results over multiple years on a map helps identify areas with frequent equipment failures to prioritize preventive maintenance.

Additionally, experienced personnel working remotely can review data sent from the field and promptly provide appropriate advice, preventing on-site judgment errors and enabling rapid response. A cloud-connected inspection system not only improves on-site efficiency but also promotes total DX in distribution equipment management, from information sharing after inspections to analysis of long-term data.

Standardization and labor-saving of inspection processes and support for training new technicians

Systems leveraging AR × high-precision positioning bring standardization and labor savings to field inspection processes. Tasks that previously depended on veteran expertise can be standardized digitally so that "anyone can perform them with consistent quality."

For example, if the AR app incorporates equipment-specific inspection checklists and procedures, field workers simply follow the smartphone screen to complete all required inspections without omissions. This reduces human error and prevents variation in work among multiple personnel—an important advantage for quality control.

Digital assistance is also expected to reduce the labor required for inspection tasks. Faster identification of inspection targets through AR visual support, automated recording that eliminates post-processing, and other such efficiencies cumulatively shorten task time. As a result, a single worker can cover more equipment than before, helping address labor shortages. Managing more equipment with limited resources directly leads to cost reductions and workforce savings. In some cases, inspections that previously required two-person teams may be performed safely by a single person (by combining remote veteran monitoring, for example). With an aging on-site workforce and concerns about future staffing shortages, labor savings achieved through DX enable maintaining management quality with limited personnel.

Furthermore, AR inspection support is highly effective for the training and development of junior technicians. When a smartphone is pointed at equipment and its name and inspection points are displayed, even newcomers can immediately see what and how to check. The system complements knowledge without relying on veterans’ "intuition," providing reassurance. Learning while receiving guidance in front of real equipment enhances the quality of OJT (on-the-job training). Because digital-native generations are familiar with smartphone-based tasks, their motivation to learn can also increase.

Veteran technicians will welcome having their know-how accumulated in digital tools to support younger staff. As a means to eliminate the personalization of field know-how and make knowledge transfer more efficient, AR × high-precision positioning inspection support holds significant value in the power industry undergoing generational change.

Simple surveying and AR inspection support using the high-precision positioning technology "LRTK"

Finally, as a concrete solution example to easily realize AR and high-precision positioning on site, we introduce a cutting-edge technology called "LRTK." LRTK is an integrated system that enables anyone to perform centimeter-accuracy positioning and AR visualization easily using a compact RTK-GNSS receiver that attaches to a smartphone and a dedicated app. The smartphone-sized receiver is attached to the back of the device and weighs only a few hundred grams, offering excellent portability. Positioning data are wirelessly transferred from the receiver to the smartphone, where the app performs real-time AR display and recording. While many conventional AR surveying tools require pre-placed markers or complex initial calibration, with LRTK the RTK can achieve a Fix within a few tens of seconds after powering on, allowing high-precision AR to start immediately. No special calibration work is needed, and its readiness for immediate use on arrival at the site is a major strength.

LRTK also excels at cloud integration: design drawings and point cloud survey data can be downloaded to the field for AR display, and conversely, measured data can be uploaded to the cloud and shared instantly. The interface is intuitive, enabling workers without specialized knowledge to use advanced positioning and AR features.

In recent years, public-sector examples of smartphone RTK use have emerged—for instance, Fukui City in Fukui Prefecture adopted a smartphone positioning system (LRTK Phone) for disaster recovery. In this way, the usefulness of smartphone + RTK positioning + AR in infrastructure maintenance is being validated. Field cases using LRTK have reported consolidating positioning, inspection, recording, and AR display into a single smartphone, enabling small teams to complete field work. The ability to achieve on-site DX without expensive surveying equipment or large teams is a major attraction. LRTK is a versatile tool with broad applications beyond distribution equipment maintenance, including buried cable detection, disaster damage recording, and as-built management after construction.

Summary: By combining AR with RTK high-precision positioning, distribution equipment patrols and inspections are rapidly becoming smarter. The benefits—increased efficiency, improved safety, and smoother knowledge transfer—are immense. Remarkably, these advances can be realized using a familiar device: the smartphone. Overseas examples already show AR-assisted tools being used for bridge and factory equipment inspections. In Japan, initiatives such as drone and AR use for transmission line patrols are beginning, and these advanced technologies are becoming a new standard. If your organization faces challenges in equipment management, consider proactively adopting these latest technologies. The new DX-era inspection styles will greatly contribute to on-site labor savings, and to improved safety and reliability. Harnessing smartphones and cutting-edge technologies, let’s pioneer a new era of distribution equipment management.