Using AR × High-Precision Positioning for Distribution Equipment Inspections: Reducing Inspection Workload with a Smartphone

Traditional Challenges in Distribution Equipment Inspections

Inspections of electric utility distribution equipment (utility poles, transformers, switches, cables, etc.) are essential work that supports stable power supply. Typically, inspectors patrol an area, visually checking the exterior of poles and transformers for abnormalities. Tasks also include observing high-elevation equipment with binoculars and, when necessary, measuring values such as grounding resistance. However, there are limits to high-elevation work in harsh environments and to manual recordkeeping, and several issues have been pointed out in terms of efficiency and accuracy. Major problems include:

• Workperson dependence: Inspection know-how tends to rely on the experience of veteran workers, depending on individual intuition and tacit knowledge. There are concerns that quality will be hard to maintain when veterans are transferred or retire.

• Dependence on drawings and documents: On site, workers confirm equipment while referring to paper drawings and asset registers, but outdated drawings may not reflect updated information and can differ from the actual situation. In urban areas with frequent modifications, it is not uncommon for drawing information to mismatch field reality, forcing workers to rely on intuition.

• Cumbersome inspection records: Inspection results are mainly recorded manually, following a flow of taking photos → making notes → later organizing into reports. Matching photos and notes to link locations and content is tedious and carries risks of input errors or missed information. Field notes can be lost or illegible, causing extra effort in report preparation.

• Effort and risk in safety confirmation: For high-elevation work and inspections around live lines, thorough safety checks are indispensable. The process of multiple people pointing and calling out and checking off checklists is a heavy burden on-site, and human errors such as misidentifying equipment can lead to serious accidents. Completely eliminating human error is difficult, and work is always accompanied by the risk of accidents.

These issues indicate that distribution equipment inspections not only have room for efficiency improvements but also pose risks of variability in work quality and safety. In fact, there have been cases where oversights or reporting errors by less experienced personnel nearly caused trouble. Traditionally, the field has had no choice but to rely on veteran knowledge and manual labor, but in recent years there has been a movement to introduce digital technologies into this field. Against this backdrop, the power industry is accelerating initiatives for DX (digital transformation) of inspection and maintenance operations. One approach attracting attention is the next-generation inspection method that combines AR (augmented reality) technology and high-precision positioning (RTK).

Precise Visual Assistance from the Fusion of AR Technology and RTK High-Precision Positioning

AR (Augmented Reality) overlays digital information such as CG models and text on the real-world image seen through a camera. RTK (Real Time Kinematic) positioning is a high-precision GNSS (satellite positioning) technique that can pinpoint position to within several centimeters (a few in). RTK requires a base station that transmits correction signals, but in recent years nationwide network-type RTK services using infrastructures such as the Geospatial Information Authority of Japan’s Continuously Operating Reference Stations have been established, allowing mobile receivers to obtain correction data via communication. Because there is no need to install a dedicated base station on site, an environment is emerging in which centimeter-class positioning can be performed anywhere with a small receiver and a smartphone. That said, high-precision positioning requires an open sky to receive satellite signals well. Positioning accuracy can decline in areas with high-rise buildings or dense trees, but in Japan the quasi-zenith satellite “Michibiki” offers CLAS (Centimeter-Level Augmentation Service), which can provide correction information directly from satellites even outside communication coverage. Combining these technologies can achieve stable centimeter-class positioning. By combining AR and RTK, inspection work on distribution equipment can simultaneously achieve both high positional accuracy and visual clarity.

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

However, accurately overlaying digital information on the real world requires extremely precise alignment. Ordinary smartphone GPS can have meter-level errors, causing virtual equipment models displayed in AR to be far offset from their actual positions, making them impractical. Conventional AR systems often required placing markers (alignment marks) at each site or initially adjusting model positions manually. For a distributed network like a power distribution grid, it is unrealistic to place and calibrate markers at every location.

This is where RTK’s centimeter-level accuracy (cm level accuracy (half-inch accuracy)) becomes powerful. By combining a smartphone with a small RTK-capable GNSS receiver, you can obtain highly accurate absolute coordinates of your current location. Feeding this into the AR app allows digital information displayed on the smartphone screen to be overlaid with the real object with virtually no offset. In other words, marker-less, high-precision AR display is achieved, and the positional discrepancy between virtual information seen through the camera and the real object is almost eliminated. Because following AR-displayed instructions lets workers reliably operate the correct equipment, it also helps reduce the risk of accidents caused by human error, such as misoperation of switches.

Additionally, recent smartphones have models equipped with LiDAR (light detection and ranging) sensors. LiDAR can instantly capture distances and shapes of surrounding structures, enabling stable AR object placement according to the environment and accurate occlusion rendering when objects are hidden behind others. Combining RTK’s high-precision location information with smartphone AR platforms and sensor technologies is enabling precise, intuitive work support in distribution equipment inspection sites like never before.

Intuitive Inspection Work and Automated Recordkeeping with a Smartphone

Using AR × high-precision positioning does not require special large equipment or complicated operations. Recently, small RTK-GNSS receivers that can link to smartphones have appeared, making high-precision positioning easier to use. Field inspectors can use the single smartphone they always carry to intuitively obtain information while working and simultaneously keep records.

For example, an inspector can hold a smartphone in one hand, launch a dedicated app, and simply point it at equipment. The camera feed will visually indicate “the next inspection point” overlaid on the image. When aiming at the upper part of a pole, arrows may point to components prone to deterioration (insulators, metal fittings, etc.) and inspection items will be given as text instructions. If the inspector follows the instructions and takes photos, the photos will be automatically tied to the coordinates and timestamp of the shooting location and saved. There is no later guessing about which part of which device a photo captured.

Notes and observations can also be recorded entirely on the smartphone. Checklist entries and voice comment recording can be done on site, eliminating the need to write in a paper notebook and bring it back. Moreover, with a LiDAR-equipped smartphone, you can scan a concerning equipment part to obtain a 3D point cloud. For instance, if you measure the deformation of a pole or fittings as point cloud data, you can later analyze detailed dimensions back at the office for advanced assessment.

In this way, photos, notes, and point cloud measurements are performed seamlessly via smartphone and AR apps, and digital records are created automatically. All on-site data are linked to timestamps and high-precision location information, greatly reducing the need to sort photos or transcribe reports after inspection. In practice, there have been reports of workflows in which a single smartphone per person handled everything from surveying (positioning) to inspection, recording, and AR-based verification of as-built conditions, making a small-team, short-duration inspection workflow a reality without specialized equipment or large crews.

Updating Digital Asset Registers and Remote Reporting via GIS and the Cloud

Traditionally, field notes and photos were taken back to the office and manually entered into asset register systems, causing time lags in data updates and risks of input errors. With inspections using AR × RTK, inspection data collected on-site with a smartphone can be linked immediately to GIS and cloud-based digital asset register systems.

Specifically, inspection data recorded on the smartphone (photos, coordinates, inspection comments, etc.) can be uploaded immediately to an internal server via the cloud and shared with relevant departments. This allows inspection results to be reflected in internal systems in real time, so staff can grasp the latest inspection status from the office.

Key effects of digital linkage include:

• Streamlined reporting: Inspection information is automatically compiled into electronic reports, reducing later form creation and transcription tasks. Because photos with site coordinates and comments are recorded directly, there is no extra work to add location or situation information to reports.

• Real-time sharing and remote support: Cloud-based sharing makes it easy to share information between field and office, enabling remote review and instruction. In emergencies, headquarters can quickly formulate responses based on photos and detailed information sent from the field.

• Unified data management: Photos, notes, and location information are directly linked to the digital asset register, preventing information loss and delayed transmission associated with paper records. When personnel change, past data can be traced on a map, reducing concerns about missed handovers.

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

It also enables bidirectional interactions where remote experts review data sent from the field and provide immediate advice, helping prevent erroneous on-site decisions and enabling rapid response. A system that directly connects the field and cloud not only streamlines on-site work but also promotes total DX (digital transformation) of distribution equipment management, from information sharing to analysis of long-term data.

Standardization and Labor Savings in Inspection Processes and Support for Training New Technicians

A system that uses AR × high-precision positioning brings standardization and labor savings to on-site inspection processes. Tasks that used to rely on the skill level of veterans can be leveled so that “anyone can perform them to a consistent quality” through digital means.

For example, if the AR app contains checklists and procedures for each piece of equipment, on-site personnel can complete necessary inspections simply by following the smartphone screen, ensuring no inspections are missed. This reduces human error and prevents variability in work content among multiple inspectors, which is a major advantage for quality control.

Digital support is also expected to reduce the labor required for inspection work. Visual guidance via AR makes it quick to find inspection targets, and automated recordkeeping eliminates post-processing, all of which cumulatively shorten working time. As a result, one worker can cover more equipment than before, contributing to solutions for labor shortages. Managing many assets with limited resources directly leads to cost reductions and labor savings in inspection operations. In some cases, inspections that previously required two people may be conducted safely by a single person (combined with remote veteran monitoring, for example). As field personnel age and concerns about future labor shortages grow, DX-driven labor savings will help maintain equipment management quality with limited staff.

AR-supported inspection also excels in the training and development of young technicians. When a smartphone is pointed at equipment, the equipment name and inspection points are displayed, making it immediately clear to a newcomer what and how to check. The system supplements knowledge without relying on a veteran’s “intuition,” providing reassurance. Learning by receiving guidance while facing real equipment improves the quality of OJT (on-the-job training). Digital-native generations find smartphone-based work familiar, which can also improve motivation to learn.

Veteran technicians will welcome their know-how being accumulated in digital tools and used to support younger staff. As a means to eliminate workperson dependence and efficiently pass on skills, AR × high-precision positioning inspection support has significant value for the power industry during generational transition.

Simple Surveying and AR Inspection Support with the High-Precision Positioning Technology “LRTK”

Finally, as a concrete solution example to easily implement AR and high-precision positioning on-site, we introduce the latest technology called “LRTK.” LRTK is an integrated system that enables anyone to achieve centimeter-precision positioning and AR visualization using a small RTK-GNSS receiver that attaches to a smartphone and a dedicated app. The smartphone-sized receiver is attached to the back of the smartphone and weighs only a few hundred grams. Positioning data are transmitted wirelessly from the receiver to the smartphone, and the app performs real-time AR display and recording. Many typical AR surveying tools require prior marker placement or complicated initial calibration, but with LRTK you can power on the device, wait a few tens of seconds for RTK to fix (satellite lock), and immediately start high-precision AR. No special calibration work is required, and the ease of being ready to use as soon as you arrive on site is a major feature.

LRTK also excels at cloud integration: you can download design drawings and point cloud survey data on site for AR display, or instantly upload measured data from the field to the cloud for sharing. The interface is intuitive so that even workers without specialized knowledge can use advanced positioning and AR functions.

Recent public-sector examples of smartphone RTK use have emerged; for instance, Fukui City in Fukui Prefecture introduced a smartphone positioning system (LRTK Phone) for disaster recovery. In this way, the usefulness of combining smartphone + RTK positioning + AR in infrastructure maintenance is being demonstrated. On sites using LRTK, there have been reports of consolidating positioning, inspection, recording, and AR display into a single smartphone, enabling small teams to complete on-site work. The ability to realize field DX without expensive surveying equipment or large teams is a major attraction. It can be a “universal tool” effective not only for distribution equipment maintenance and inspection but also for locating buried cables, recording damage during disasters, and post-construction as-built management.

Summary: Inspection support technology that combines AR and RTK high-precision positioning is dramatically modernizing distribution equipment patrols and inspections. The benefits—improved efficiency, enhanced safety, and smoother knowledge transfer—are substantial. It is also groundbreaking that this can be achieved with an everyday device like a smartphone rather than special equipment. Overseas, AR support tools are already being introduced for inspections of bridges and factory equipment. Domestic initiatives such as drone and AR use for transmission line patrols are also beginning, and the use of these advanced technologies is becoming a new standard. If your company feels challenges in equipment management, consider proactively adopting such cutting-edge technologies. A new inspection style for the DX era will greatly contribute to on-site labor savings and improvements in safety and reliability. Embrace smartphones and advanced technologies to pioneer a new era in distribution equipment management.