Digitalization from Surveying to As-Built Management: A Field Revolution in Solar Construction

At solar power plant construction sites, digital technologies are gradually permeating processes from surveying to as-built management, and on-site operations are beginning to change dramatically. Construction that installs thousands to tens of thousands of solar panels across vast land areas involves a wide range of tasks, including topographic surveying, checking progress of earthworks, verifying panel and racking layouts, and preparing construction records. Traditionally, many of these tasks were handled manually and on paper, leading to significant issues in terms of efficiency and accuracy. Now, digitalization is solving these problems and bringing about a "field revolution" that delivers benefits such as labor reduction, higher precision, prevention of work errors, and faster information sharing. This article explains the flow of digitalization from surveying to as-built management on solar construction sites and its effects.

Current State and Challenges of Solar Construction Sites

Many processes at solar power plant construction sites are still managed using analog methods. For example, traditional surveying required specialized instruments such as total stations and surveying personnel, and the obtained measurements were written by hand on paper drawings. Work instructions were often communicated verbally or by phone or email, and on large sites site supervisors had to walk around to inspect progress in person, which was a heavy burden.

Furthermore, delays in information sharing between processes often lead to mistakes and rework. It can take time to confirm whether earthworks have been graded to the planned elevations, and discrepancies discovered later can result in rework. Management of site photos and the preparation of as-built documents and reports have also been mainly manual, placing a heavy burden on site agents and supervisors. Such person-dependent and inefficient management is becoming unsustainable amid labor shortages and an aging workforce of skilled technicians, and prompt improvements are required.

Background Driving the Need for Digitalization

A key solution gaining attention for fundamentally addressing these site challenges is construction site DX (digital transformation). It is not enough to simply digitize paper; efforts are needed to transform the business processes themselves through digital technologies to dramatically improve productivity and accuracy. The urgency of DX on solar construction sites is driven mainly by the following factors.

1\. Labor shortages and skills transfer issues: Managing vast sites normally requires many workers, but the construction industry as a whole faces a shortage of young personnel and an aging population of skilled workers. To operate complex sites with limited staff, improving each individual's productivity is essential. Advancing labor-saving and automation of surveying and management tasks through DX will be a key to future site operations.

2\. Demand for shorter construction periods and cost reduction: With rising demand for renewable energy, early commissioning of solar power plants is required. Efficient execution of construction is crucial for business, and using digital technologies to shorten surveying and inspection times and to share data instantly is expected to reduce wasted waiting time and rework. DX brings significant effects both in shortening schedules and cutting costs.

3\. National-level promotion of DX: Policies such as the Ministry of Land, Infrastructure, Transport and Tourism's "i-Construction" strongly encourage the use of ICT and 3D data in the construction industry. Solar power plant sites are no exception, and the adoption of the latest technologies—such as drone surveying, visualization with AR, and remote supervision—is expected to improve safety and quality.

High-Precision Surveying and Recording Easily Achieved with a Smartphone

One concrete tool supporting DX is "site management using smartphones." Recent smartphones have become highly capable; some models even include high-precision GNSS modules for positioning and 3D scanners (LiDAR). By attaching a dedicated compact RTK-GNSS receiver to a smartphone, a palm-sized smartphone can instantly transform into a surveying instrument with centimeter-level accuracy (half-inch accuracy). Where total stations or large GPS surveying equipment and trained surveyors were once required, now site personnel can record coordinates of required points instantly by simply pressing a button on a smartphone app. The acquired latitude, longitude, and elevation data are saved automatically, eliminating the need to jot notes on paper.

Also, by leveraging smartphone cameras and various sensors, site record-keeping can be dramatically streamlined. When a point of interest is photographed, the image file is automatically tagged with the shooting location coordinates and timestamp. There is no need to jot notes on paper drawings while taking photos—records can all be stored as digital data. Since recorded data can be uploaded to the cloud on the spot, the effort of returning to the office to recreate reports is also reduced.

By centering operations around a single smartphone, a system is emerging that allows the full sequence from surveying to recording and sharing to be completed on site. Because familiar smartphones are used, both veterans and younger workers can adapt easily, and by deploying a one-device-per-person digital field tool, unprecedented agility and efficiency can be achieved.

Visualizing Progress and As-Built with 3D Point Cloud Data

In earthworks for solar power plants, large-scale fill and cut operations are carried out, so accurately understanding site topography and managing progress and earthwork volumes is extremely important. This is where the power of 3D point cloud data comes into play. Point cloud data refers to three-dimensional survey data recorded as an aggregate of countless points (point cloud) representing the surrounding environment.

Traditionally, such 3D surveying required specialized methods like ground-based laser scanners or photogrammetry from drone aerial photography. However, in recent years some smartphones have been equipped with LiDAR (light detection and ranging) sensors, and by combining these with high-precision GNSS positioning, anyone can now easily perform on-site 3D scans. Simply walking around the site with a smartphone can capture point cloud data of terrain and structures, and each point is assigned geodetic coordinates (latitude, longitude, and height) so scan results are recorded with accurate positional information.

Using such 3D point cloud data greatly streamlines progress tracking and earthwork quantity management. For example, by scanning the terrain before earthworks begin and saving that data, then comparing it with periodic subsequent scans, you can accurately quantify how much earth has been cut or filled. Tasks that used to require surveyors to measure heights at multiple points and compute volumes from cross sections can now be automated by performing digital difference calculations between point cloud datasets, drastically shortening the time required. Moreover, overlaying the scanned as-built data with the planned design terrain highlights excess or deficit earth volumes and shape deviations at a glance.

Point clouds are also powerful for progress management. Subtle terrain changes and work progress that are difficult to perceive with the naked eye can be compared in detail using 3D data. This allows early detection of areas lagging behind schedule or where finishing quality is problematic so countermeasures can be taken. On vast sites such as mega-solar facilities, uniformly grasping the entire site was previously difficult, but by utilizing point cloud scans, the whole site can be digitally "visualized" point by point.

Checking Design Data Against the Site with AR Technology

AR (augmented reality) technology is another promising solution that demonstrates strong effectiveness in on-site management for solar construction. By holding a smartphone or tablet up, design data can be overlaid on the live site view through the camera, allowing real-time comparison of planned drawings with the actual site conditions.

Specifically, overlaying panel layout drawings or 3D models of earthwork plans in AR on the actual site makes it possible to visualize the completed image of equipment that has not yet been installed. For example, during foundation work, AR can display the positions where panel racks will be installed, enabling confirmation that marked pile positions match the design. Where traditional methods used tape measures and transits for setting out and verification, AR enables intuitive detection of misalignments and helps reduce human error.

Not only construction personnel but also clients and designers visiting the site can share the vision of the completed project through a tablet. Explanations such as "panels will be arranged like this here in the future" can be presented as 3D visuals overlaid on the real landscape, making it easier for all stakeholders to grasp the spatial image.

AR is also effective for setting out in locations that were previously difficult. Even on steep slopes or in areas hard to access, AR can display virtual markers (stakes or lines), enabling safe position verification. Resolving gaps between design and site using AR strongly supports smooth construction without rework.

Automating Site Records and Cloud Sharing

The benefits of digitalization extend beyond technical aspects such as surveying and design verification. It also brings great effects in automating and streamlining daily site records and reporting tasks. During construction of a solar power plant, vast amounts of record-keeping occur—progress photos, various inspection records, daily and weekly reports, and more. DX enables these tasks to be automated as much as possible and establishes systems for cloud-based sharing.

For example, when a photo is taken with a smartphone app, the image file is automatically linked with metadata such as date and time, location information, and the person responsible. Albums can be separated by work area and descriptive notes can be added to photos; by entering required items following templates, standardized records can be maintained. Since captured data is uploaded to the cloud in real time, there is no need to later copy images to office PCs or send them as email attachments.

Report generation can also be simplified through DX. Daily and weekly reports, as-built management documents, and other forms that site supervisors previously prepared using spreadsheets or paper can now be automatically generated from digital data collected on site. For example, simply mapping surveying data and photos into a predetermined cloud format can leave a near-complete progress report. Managing data in the cloud also allows anyone to access the latest information and prevents mistakes caused by using outdated drawings or data.

Cloud sharing also serves as a bridge connecting the site and remote locations. Managers and clients in distant offices can view site progress data and photos anytime via the Internet. This eliminates the waste of printing and carrying large amounts of paper to reporting meetings and speeds up decision-making. With centralized data management, construction records are easily referenced during post-handover maintenance and inspections, enabling DX benefits to be realized across the entire lifecycle of the solar power facility.

Case Study: Effects of DX on the Site

In practice, when a large-scale solar power plant construction site introduced a smartphone-centric DX tool, on-site management changed dramatically. As-built surveying that had previously been outsourced to an external surveying company and performed only about once a week could be carried out daily and quickly by site staff themselves, enabling construction management to be based on up-to-date terrain data at all times. AR-based design verification drastically reduced construction errors, preventing additional remedial work. In addition, photos and records shared via the cloud were viewable in real time by headquarters and subcontractors, greatly improving communication among stakeholders.

Reported major effects include the following:

• Reduced time for surveying and inspection work: Time required for surveying and inspection was reduced to a fraction of the previous amount, leading to lower labor costs and shorter schedules.

• Improved construction quality: Construction checks using AR and point cloud data reduced rework, cutting losses due to errors.

• Faster information sharing: With data immediately linked to the cloud, time spent waiting for instructions or reports was shortened.

• Easier skills transfer: Smartphone-centered tools are intuitive for both veterans and younger workers, making it easier for those unfamiliar with IT to become proficient.

• Improved safety and environmental impact: Survey work in hazardous areas decreased, and paper reduction through digitization contributed to environmental benefits.

Thus, promoting site DX brings innovation not only to productivity and quality but also to ways of working and safety. The effects are particularly pronounced at construction sites for solar power plants with large areas.

Solar Construction DX Realized with LRTK

One solution that strongly supports such site DX is our LRTK. LRTK is a smartphone-based site DX platform that provides all-in-one functionality required for site management through a dedicated compact GNSS receiver, a companion app, and cloud services. With this single solution, LRTK covers everything from simple surveying to precise positioning with RTK guidance, as-built management using point cloud scans, and cloud synchronization of site data, enabling anyone to easily implement advanced digital construction management.

For example, with LRTK, centimeter-level positioning and 3D scanning allow a single person to efficiently perform surveying and inspections. Features such as AR display of design drawings on the smartphone screen and RTK guidance that navigates the smartphone to specified coordinates for stake placement help prevent construction errors and reduce labor. All information captured and recorded on site is automatically synchronized to the cloud, allowing office personnel to instantly view and analyze it, and enabling smooth real-time remote support and progress sharing.

The LRTK series is compatible with the Ministry of Land, Infrastructure, Transport and Tourism's i-Construction initiative and is an optimal solution for promoting digitalization in construction and civil engineering. By adopting these latest tools, the benefits of labor reduction, higher precision, error prevention, and rapid information sharing at solar construction sites can be easily realized. As a step toward advancing the digital revolution on your sites, please consider utilizing LRTK.

For details on LRTK, please also visit the [LRTK official site](https://www.lefixea.com/lrtk).