DX for Mega-Solar Site Management – Point Clouds and AR Completed with a Smartphone

Current State and Challenges of Mega-Solar Site Management

Interest in renewable energy is growing across Japan, and the construction of large-scale solar power plants—so-called "mega-solar" projects—is increasing. At these mega-solar sites, tens of thousands of solar panels are installed over vast areas, requiring large-scale earthworks and installation work. Site management therefore demands a wide range of tasks, including terrain surveying, progress checks for earthworks, verification of panel and mounting-structure placement, and documentation of construction status.

However, many aspects of mega-solar site management remain analog. For example, surveying typically requires specialized equipment and personnel, survey results are often written by hand onto paper drawings, and work instructions are commonly conveyed orally or via phone and email. On expansive sites, simply grasping progress often forces staff to walk every corner of the area, imposing a heavy burden.

On large sites, insufficient information sharing across processes often leads to mistakes and rework. For instance, confirming whether earthworks have achieved the planned elevation can be time-consuming, and if discrepancies are discovered later, additional labor is required to correct them in subsequent stages. Managing site photos and preparing reports is often done manually, placing another major load on staff. With shortages of personnel and engineers becoming more serious, there is a clear need to reconsider traditional, person-dependent, and inefficient site management methods.

Background Necessitating DX

One key solution attracting attention for these site management issues is digital transformation (DX) in construction sites. DX refers to fundamentally transforming and upgrading business processes through the use of digital technologies. Several factors drive the need for DX at mega-solar construction sites.

First is labor shortages and an aging workforce of skilled technicians. Managing expansive sites requires many personnel, but the construction industry overall lacks young talent while experienced workers are aging. Improving individual productivity is essential when operating complex sites with limited staff, making it urgent to advance labor-saving measures and automation through DX.

Second is increasing pressure to shorten construction periods and reduce costs. As demand for renewable energy grows, early commissioning of mega-solar plants is expected, making efficient execution of construction commercially important. Using digital technologies to shorten surveying and inspection times and to share data instantly is expected to reduce wasted waiting time and rework.

Third is a nationwide and industry-wide push to promote DX. Initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism's i-Construction encourage the use of ICT and 3D data in civil engineering and construction. Mega-solar sites are no exception, and adopting the latest technologies for visualization and remote supervision is expected to improve safety and quality.

Given these factors, the need is not only to replace conventional methods with digital tools but to transform site management itself via DX.

Surveying, Recording, and Management with Just a Smartphone

What specific tools are effective for DX? One answer is site management that can be done with a single smartphone. Modern smartphones have become highly capable, and some models now include high-precision GPS units for positioning and 3D scanners (LiDAR). By leveraging these, tasks that previously required dedicated surveying instruments and PCs can increasingly be completed with just a smartphone.

For example, attaching a dedicated RTK-GNSS receiver to a smartphone can instantly turn the phone into a centimeter-level surveying device. Previously, operating total stations or large GPS surveying equipment required trained surveyors, but with a smartphone app you can record position coordinates by pressing a button, allowing site personnel themselves to immediately survey required points. The acquired latitude, longitude, and elevation data are saved automatically, eliminating the need for handwritten notes.

Also, by using the smartphone camera and sensors, site documentation is dramatically streamlined. When a problematic spot is photographed, the photo can automatically be tagged with the shooting location coordinates and timestamp. The hassle of jotting notes on paper drawings while taking photos disappears, and everything is recorded digitally. Collected data can be uploaded to the cloud on the spot, reducing the post-office work of reorganizing reports after returning to the office.

By centering workflows around a single smartphone, the environment is being established in which surveying, documentation, and information sharing can all be completed on-site. Because workers are already familiar with smartphones, they are easier to adopt in the field, and equipping each person with a digital on-site tool delivers mobility and efficiency previously unattainable.

Progress Checks and Volume Management Using Point Cloud Data

In mega-solar construction, large-scale terrain formation and earthworks for filling and cutting materials are carried out, so accurately understanding the site shape and managing progress and earth volumes is crucial. This is where 3D point cloud data becomes powerful. Point cloud data records the surrounding environment as a collection of countless points (a point cloud) and represents three-dimensional surveying data.

Historically, such 3D surveys used laser scanners or photogrammetry from drone imagery and other specialized methods. Recently, however, some smartphones equipped with LiDAR sensors combined with high-precision positioning have made it possible for anyone to easily perform 3D scans of a site. Simply walking the site while carrying a smartphone allows you to collect point cloud data of terrain and structures, and because each point can be tagged with global coordinates (latitude, longitude, and elevation), scan results can be recorded with accurate position information.

Using this 3D point cloud data greatly improves efficiency in progress checking and earth volume management. For example, scanning the terrain before earthworks begin and saving that data, then comparing it with periodic follow-up scans, lets you quantify how much soil has been removed or added. Tasks that once required surveyors to measure heights at multiple points and calculate volumes from cross-sections can now be done by simply subtracting point clouds to automatically compute volume differences, dramatically shortening the process. Overlaying scanned as-built data with planned design terrain also makes discrepancies (excess or deficit earth volumes and shape deviations) instantly apparent.

Point clouds are also powerful for progress monitoring. Subtle terrain changes or degrees of completion that are hard to see with the naked eye can be compared in detail with 3D data. This enables early detection of areas falling behind schedule or parts with finishing issues, allowing corrective actions to be taken. On expansive sites like mega-solar farms, it used to be difficult to uniformly grasp the entire area, but point cloud scanning makes it possible to digitally "visualize" the whole site as a cloud of points.

Real-Time Verification of Design and Site with AR

Augmented reality (AR) technology is another notable solution that can significantly aid mega-solar site management. AR enables you to overlay design data onto real site views through a smartphone or tablet screen, meaning you can verify plans against actual conditions in real time.

Specifically, layout drawings or 3D models of earthworks plans can be displayed in AR and composited onto the actual landscape. Through a smartphone camera, rows of solar panels that have not yet been installed or the locations of equipment can be seen as if they were already there. When combined with high-precision positioning, AR will not drift after a few meters of walking, allowing you to continuously verify that design and actual positions align precisely.

This AR-based verification helps prevent construction errors and improve quality. For example, during foundation work, you can project the mounting-frame positions in AR and confirm whether marking positions are correct. Tasks that previously relied on tape measures or transits for setting out can be intuitively checked with AR, reducing human error. Additionally, when clients or designers visit the site, AR can be used to share a completed visualization: showing "this is how the panels will be lined up here" in 3D over the real scene helps all stakeholders share a spatial image.

AR is also effective for setting out in hard-to-access locations. On steep slopes or areas difficult to enter, AR can display virtual markers (stakes or lines), enabling safe position checks. By using AR, the gap between design and construction is bridged in real time, supporting smooth construction with minimal rework.

Automation of Photos, Records, and Reports and Cloud Sharing

The benefits of site DX extend beyond surveying and design verification. Daily photo documentation and reporting tasks can also be greatly streamlined and automated. During mega-solar construction, many record-keeping tasks occur, such as progress photography, various inspection records, and the preparation of daily reports. DX enables these tasks to be automated as much as possible and organized for cloud-based sharing.

For example, when a photo is taken with a smartphone app, metadata like date, time, location, and the responsible person can automatically be attached to the file. Photos can be organized into albums by work area, and entering descriptions can be standardized via templates to maintain consistent records. Data is uploaded to the cloud in real time, eliminating the need to copy photos via USB or send them as email attachments after returning to the office.

Report creation can also be simplified through DX. Daily and weekly reports, as-built management documents, and other forms that site supervisors previously prepared in spreadsheets or on paper can be auto-generated from the digital data collected on-site. For instance, by mapping surveyed data and photos into predefined cloud templates, a progress report can be almost complete automatically. Managing data in the cloud also ensures everyone has access to the latest information, preventing mistakes from referencing outdated drawings or data.

Cloud sharing also serves as an effective bridge between the site and remote locations. Managers and clients in distant offices can view progress data and photos over the internet at any time. This reduces the need to print and carry大量の紙資料 to meetings and speeds up decision-making. Centralized data management also makes it easy to reference construction records for maintenance and inspections after handover, allowing DX benefits to apply throughout the lifecycle of the mega-solar facility.

Case Studies and Effects of Implementation

In practice, when a certain mega-solar construction site introduced a smartphone-complete DX tool, site management was transformed. Tasks that had been outsourced to external survey companies and performed about once a week could now be carried out by site staff in short daily sessions, enabling construction management based on always-up-to-date terrain data. AR-based design verification drastically reduced construction errors and prevented the need for additional work. Photos and records shared via the cloud were accessible in real time by head office and partner companies, greatly improving communication among stakeholders. Reported outcomes of such on-site DX adoption include the following:

• Shortened time for surveying and inspection tasks: Work times were reduced to a fraction of previous durations, leading to labor cost savings and schedule compression.

• Improved construction quality: Checks using AR and point clouds reduced rework and cut losses due to mistakes.

• Faster information sharing: Immediate cloud synchronization of data shortened waiting times for instructions and reports.

• Easier technology transfer: Smartphone-centric tools are intuitive for both veterans and younger workers, making it easier for those less familiar with ICT to become proficient.

• Safety and environmental benefits: Fewer surveying tasks in hazardous locations and reduced paper use through digitization contribute to safety and environmental improvements.

Thus, DX-driven innovations in site management not only enhance productivity and quality but also positively affect working styles and safety. These effects are particularly pronounced on large-scale sites like mega-solar farms.

Promoting Site DX with LRTK and Suggested Uses

One solution gaining attention for strongly supporting such site DX is LRTK. LRTK is a smartphone-based site DX platform that provides all-in-one functionality required for site management through a compact dedicated GNSS receiver, an app, and cloud services. Specifically, it enables the following advanced functions with just a smartphone:

• High-precision positioning and point cloud scanning: An RTK-GNSS receiver attached to a smartphone lets you constantly know your on-site position to centimeter-level accuracy. Combined with the phone's LiDAR, you can obtain absolute-coordinate-attached 3D point cloud data with a single touch. This enables on-the-spot measurement of fill quantities and visualization of progress.

• AR-based verification of site and design: Design drawings and 3D models can be displayed in AR on the smartphone screen and superimposed on the real scenery for verification. LRTK's high-precision positioning prevents AR from drifting, ensuring accurate placement. You can overlay virtual models on structures under construction or mark stake positions in AR for practical use.

• Automatic organization of photos and records: Photos taken with the LRTK app are automatically tagged with coordinates and timestamps and managed in the cloud alongside maps and point cloud data in chronological order. You can even display past photos at the same location in AR for comparison, aiding observation of changes over time and report generation.

• Coordinate navigation: The app can navigate you to any point on design drawings. This enables a single person to reliably perform tasks like "install a stake at the specified coordinate" or "place equipment X meters from this point."

• Cloud sharing and team collaboration: All data acquired with LRTK is automatically synchronized to the cloud and can be viewed and measured immediately from a PC browser. Office-based engineers can quickly review on-site point clouds and photos and provide guidance, enabling smooth real-time collaboration.

By leveraging LRTK, surveying, checking, verification, recording, and sharing processes required for mega-solar site management can all be completed with a smartphone. Because these DX functions are integrated into a single tool, onsite adoption is straightforward. For large-scale solar power plant construction sites, LRTK can be a reliable partner for efficiency and quality improvement. When considering DX for site management, it is worth exploring the adoption of such smartphone-complete cutting-edge technologies.