Improving Construction Efficiency at Solar Power Plants | Visualizing Terrain with Point Cloud Data Using LRTK Smartphone Surveying | LRTK Surveying Completed with Just a Smartphone

Introduction: What “efficiency” means on solar power construction sites

On solar power plant construction sites, efficiency is always required. Large-scale solar panel installation work covers wide areas, and completing projects within short schedules is important from a business perspective. With limited personnel tasked with arranging numerous solar panels in mountainous areas or former farmland, waste-free work planning and speedy construction are indispensable. In recent years, attention to renewable energy projects has increased, and the number of solar power plant projects has grown. At the same time, labor shortages and an aging skilled workforce have progressed, making it difficult to cope with the old, experience-dependent, and inefficient methods used on some sites.

So what specifically does “efficiency” mean on solar power construction sites? It does not simply mean rushing the work; it means eliminating unreasonable tasks and waste, and proceeding through the process accurately and smoothly. The ideal is to reduce rework and surveying mistakes so that installation is done correctly the first time. Smooth information sharing between the site and the office and minimizing waiting time and communication losses also contribute to improved efficiency. One key to achieving this efficiency is the use of digital technology. In particular, in the foundational field of on-site “surveying,” new smartphone-based solutions are poised to dramatically change site efficiency.

The role of surveying in the solar power plant construction process

Surveying plays an essential role in supporting the design and construction processes of solar power plants. While surveying may be thought of as work for specialized technicians, surveying data are used at many stages from planning to completion on a solar power plant. For example, surveying is needed in the following phases:

• Pre-design site investigation: This is the stage for understanding the candidate site’s terrain. Accurately measuring site elevations, slopes, and surface forms helps with solar panel layout plans and earthwork (cut-and-fill) plans. Traditionally, surveyors used transits or GPS devices to measure many control points and create topographic maps.

• Layout marking and piling at the start of construction: This involves marking positions on site to place piles or indicate the extent of earthworks according to the design drawings. In solar panel projects, which require marking many piles and supports, experienced survey staff calculate dimensions from drawings and place stakes or markings on the ground. This process consumes manpower and time, and mistakes can lead to misaligned arrays.

• Progress checks during construction: Surveying performed during earthworks or foundation work to confirm whether construction is proceeding as designed. For example, checks determine whether the ground has been leveled to the specified elevation, whether the fill volume matches the plan, or whether foundation placements have shifted. Additional surveys are conducted as needed to identify deviations from the design.

• Inspection and recording at completion: After work is finished, the installed facility is inspected and recorded to confirm conformance with design drawings. While solar power plants may not require the same strict as-built control standards as heavy civil structures, measuring the shaped terrain and the positions and elevations of installed structures helps with future maintenance planning and land registry records.

Surveying data thus form an indispensable information foundation for design, construction, and maintenance stages of solar power plants. Conversely, if surveying is time-consuming or lacks accuracy, it affects the entire subsequent process. For example, insufficient initial topographic surveys may cause design errors, which could surface during construction as problems like “the slope was steeper than planned” or “not enough fill.” If pile layout is off, panel rows may curve or interfere with adjacent equipment. Therefore, it is no exaggeration to say that fast and accurate surveying directly influences construction efficiency and quality at solar power plants.

The impact of visualizing terrain data

Recently, the construction industry has advanced efforts to visualize site terrain and construction status with digital data. Where situations were once understood via paper drawings and site photos, it is now possible to visualize sites with rich data like 3D models and point clouds. Solar power plant construction is no exception—digitizing terrain brings many advantages.

First, visualizing terrain data deepens the shared understanding among stakeholders. For example, designers can review acquired 3D terrain models on a PC while considering layouts. Intuitively grasping undulations and slopes allows accurate decisions such as “let’s cut and flatten this hilly area” or “avoid this spot that will be shaded.” Site supervisors and construction managers also find that a visual terrain model conveys the situation more intuitively than numerical reports, enabling clearer instructions.

Digitizing terrain also helps optimize construction planning. For instance, comparing pre-earthwork terrain data with post-design data allows simulation of how much excavation and fill are needed where. Required soil volumes can be calculated in advance, enabling efficient arrangements for dump trucks and disposal plans. Because solar panel output depends on solar incidence angles, terrain models can be used for seasonal shading simulations and fine-tuning panel layouts. When data are presented in a visible form, decisions that used to rely on experience can be made scientifically and quantitatively.

Additionally, visualizing terrain and construction-status data excels in recording and verification. Accumulating drone aerial photos and 3D scan data taken during construction creates a digital record that can later be reviewed to see “when, where, and what happened.” If ground subsidence or defects are discovered after construction, comparing with historical terrain data aids root-cause analysis and planning repairs. In this way, visualizing the site with data produces substantial benefits for both construction efficiency and quality control.

What is point cloud data? Features and advantages

A commonly used data format for 3D visualization of terrain and structures is point cloud data. Point clouds are collections of numerous points with spatial coordinates that represent surface shapes by many discrete points. For example, when terrain is surveyed by a laser scanner, the result is dense sets of points on hills and valleys. When plotted, this collection of points looks like a three-dimensional reproduction of the terrain.

The defining feature of point cloud data is that it contains highly detailed 3D information. Each point has X, Y, Z coordinates (and sometimes color or reflectance intensity), recording fine surface details of ground and structures. Complex shapes that flat plans or numerical data cannot fully represent can be preserved in point clouds as “clusters of points,” allowing arbitrary cross-sections to be taken and dimensions measured afterward. It is essentially a digital replica of the actual site.

There are many advantages to using point cloud data on solar power sites. First, a single measurement can acquire a vast number of measurement points, so there are few omissions like “I wish we had measured that spot’s elevation.” Needed information can be extracted from the point cloud, reducing re-surveying. Second, point clouds are visually intuitive—terrain irregularities appear directly as point density and distribution, making differences easy to understand even for non-specialists. Third, recent software and cloud services have made point cloud handling easier; you can freely rotate and zoom models on a PC and perform automatic volume calculations and comparisons, creating an environment where data utilization is straightforward.

However, conventional point cloud acquisition required expensive 3D laser scanners or drone imaging equipment and often specialized operators, which posed a barrier for small sites. In recent years, advances in camera and sensor technology have produced more accessible methods for obtaining point clouds. One such method is point cloud measurement using smartphones. Let’s look at how LRTK surveying completed with just a smartphone works and what strengths it offers.

How LRTK smartphone surveying works and its strengths

The increasingly popular LRTK smartphone surveying leverages a small device attached to a smartphone and a dedicated app to make previously specialist, high-precision surveying accessible to anyone. “LRTK” is a proprietary solution that develops Real-Time Kinematic (RTK) positioning techniques, and when combined with a smartphone it achieves centimeter-level positioning accuracy. Specifically, a slim RTK-GNSS receiver attached to the phone accurately computes satellite position information and provides real-time coordinates to the smartphone app. This allows a smartphone to determine its current position with accuracy comparable to traditional surveying instruments.

A major functional advantage of LRTK smartphone surveying is that it does more than simply measure position: it enables easy acquisition of on-site 3D data by integrating the smartphone’s camera and sensors. By launching the dedicated app and pointing the camera while walking, you can record surrounding terrain and structures as point cloud data. This combines smartphone-integrated LiDAR (light-based distance measurement) or image analysis (photogrammetry/SfM techniques) that reconstruct shapes from camera images with LRTK’s high-precision self-positioning. Conventional AR scanning on a phone suffered from coordinate drift as you walked, but LRTK continually corrects the global coordinates via GNSS, enabling stable measurements without point cloud distortion over long distances.

The point clouds obtained this way are tagged from the start with absolute coordinates such as latitude/longitude and elevation. In other words, when you later overlay this data on CAD drawings or other geographic information, it lines up precisely. Creating point clouds from drone photos often required separate ground control points for georeferencing, but LRTK smartphone surveying is groundbreaking because it provides correctly referenced coordinate data on site immediately. Acquired point clouds and coordinate data can be uploaded to the cloud with one click from the phone and shared and viewed on office PCs right away. There is no need to install dedicated PC software; you can rotate and measure 3D point clouds in a browser and overlay them with drawings. This makes it easy to confirm measured data with all stakeholders the same day and apply it to decisions—supporting a form of speed-driven management.

The strengths of LRTK smartphone surveying can be summarized as follows:

• Portability and ease of use: Because only a smartphone and a palm-sized receiver are required, there is no need to carry heavy tripods or equipment. Site workers can keep it in a pocket and measure whenever needed.

• Single-person operation: Surveying and layout tasks that traditionally required two people can now be performed by one person with a smartphone. Guidance is displayed on the phone screen, enabling accurate positioning without auxiliary staff.

• Multifunctionality: One device can handle recording measurement points, point cloud scanning, layout guidance, photo records, and AR display. For example, you can scan terrain in the morning, compare it with design drawings on the same data in the afternoon, and display pile positions in AR for marking in the evening—completing the workflow on the same device.

• High accuracy: RTK-GNSS improves positioning accuracy from the meter-level error typical of general smartphone GPS to centimeter-level. Experiments have shown horizontal positioning errors of about 1–2 cm for single measurements, and averaging over time can achieve sub-centimeter precision. Vertical measurements are corrected with a geoid model to provide survey-grade elevations suitable for civil engineering.

• Real-time AR use: The high accuracy allows design data to be overlaid on the real world through the smartphone screen with minimal misalignment, enabling intuitive on-site checks. For example, the designed finished surface can be projected onto the ground in AR to show how much more soil must be removed in color, or virtual piles can be placed on the ground to visualize pile positions. Digitizing tasks previously dependent on craftsmen’s intuition prevents misunderstandings and lets anyone proceed without guesswork.

• Offline capability: In addition to Internet-based corrections, LRTK receivers support centimeter-level augmentation information (CLAS) broadcast by Japan’s Quasi-Zenith Satellite System “Michibiki.” This means surveying can continue using satellite correction signals even in mountainous areas with no cell service. For remote solar plant construction, there is no need to worry about surveying stopping due to no network coverage.

• Low-cost adoption: Although details are discussed elsewhere, it is worth noting that initial costs can be kept lower compared to purchasing dedicated expensive equipment. Providing one device per worker is realistic, making it easier to roll out as a DX tool across an organization at an accessible price point.

On-site use cases (pre-earthwork / during construction / as-built control)

Below are concrete scenes of how LRTK smartphone surveying can be used at solar power plant sites along the construction progress.

• Pre-earthwork (pre-construction survey): Before work begins, smartphone surveying can quickly measure the site terrain. Walking and scanning the surface captures elevation differences and terrain shape as point cloud data. Designers can use this data to create optimal layouts and earthwork plans. Accurately estimating cut-and-fill volumes before mobilization prevents shortages or excesses of earthwork materials during construction and reduces costs. By overlaying existing terrain and design models in the cloud before starting, issues such as “the northern panels will be shaded by the slope as-is” can be identified early and design revisions made easily. Processes that used to take days to weeks from initial survey to design reflection can, with LRTK, enable same-day sharing of terrain data and immediate design review.

• During construction (progress management and pile placement guidance): LRTK smartphone surveying is useful during earthworks and piling phases. For example, after a bulldozer levels the ground, simply walking the site with a smartphone collects the finished ground point cloud. Comparing it with the design finished ground elevation in the cloud makes it obvious whether the surface has been leveled to the specified height. Low or excessively high fill areas can be color-coded, enabling clear instructions to equipment operators. For pile installation, importing pile coordinate data from design drawings into the app lets the smartphone guide workers like a car navigation system to the correct points. The screen can display guidance like “0.1 m east, 0.05 m north to the target point,” and switching to AR mode overlays virtual arrows or pile markers on the camera view to indicate placement points. This allows less experienced staff to identify pile positions without confusion, enabling site staff without surveying expertise to complete pile layout themselves. In the field, there are also reported maintenance use cases where geotagged photos saved to the cloud beforehand helped teams head straight to repair locations using the photo-positioning function. The ability to measure and confirm on the spot at various moments during construction greatly reduces process losses.

• As-built control (final inspection and records): At project completion, LRTK can easily create 3D as-built records of completed terrain and structures. Scanning the entire site after earthworks yields a detailed point cloud of the finished ground. Comparing this with the design data makes it possible to inspect the entire site for conformance. Areas piled too high or insufficiently excavated beyond tolerance will be automatically highlighted in color, making it easy to see where corrections are needed. For vast solar plant sites, combining drone imaging or LRTK drones (large-scale solutions) can quickly cover the whole site, with walk-based scans filling in details. As-built point cloud data can be organized directly as deliverables for electronic submission or shared as materials for stakeholders, contributing to streamlined preparation of inspection documents. Storing these 3D as-built records also creates an asset that allows accurate recreation of past conditions for future facility expansions or inspections, supporting lifecycle management of the plant.

Effects of adoption: impacts on construction efficiency, quality, and cost

What specific effects can be obtained by adopting LRTK smartphone surveying? Below are the impacts summarized from the perspectives of the main points: construction efficiency, quality, and cost.

• Improved construction efficiency: Surveying and layout work time can be drastically shortened compared with traditional methods. Tasks that previously required several people and half a day—such as layouting pile positions—can be completed by one person in a few hours. The ability to measure immediately when needed reduces waiting time. Site supervisors can perform checks without waiting for surveying teams, alleviating bottlenecks across the schedule. Cloud sharing reduces the effort to prepare reports from the field and compresses the time spent organizing data and producing drawings. As a result, effects appear as shorter schedules and productivity improvements, enabling more projects to be handled with limited time and personnel.

• Improved quality: Higher surveying accuracy and more frequent checks improve construction quality. For example, pile position errors kept within a few centimeters increase panel alignment accuracy and reduce strain on cabling and connectors. In earthworks, constant leveling to the design cross-section prevents ponding in low areas and avoids material waste from excessive fill. Repeated real-time measurement and verification during construction reduce rework and standardize finish accuracy. Combining photos and point clouds for records allows detailed tracing of construction status later, raising the standards of quality assurance and trouble response. In short, LRTK smartphone surveying contributes not only to working “faster” but also to building things “correctly,” laying the foundation for high-quality solar power plants.

• Cost reduction: Efficiency and quality improvements ultimately lead to cost savings. In terms of labor costs, reducing the number of people and hours required for surveying cuts those expenses. Outsourced surveying costs can be reduced if previously outsourced tasks are performed in-house. Reducing rework lowers wasted material and heavy equipment operating costs. Shorter schedules decrease site overheads (temporary offices, security, temporary facilities), and earlier power generation reduces lost revenue opportunities. The adoption equipment itself is more affordable than large laser scanners or dedicated surveying instruments, and training costs are lower. Overall, adopting LRTK smartphone surveying offers very high return on investment.

Frequently asked questions (accuracy / usability / operating environment, etc.)

Finally, here are common questions from site personnel about LRTK smartphone surveying in Q&A format.

Q: Can smartphone surveying really achieve centimeter-level accuracy? A: Yes. In environments where satellites can be properly received, horizontal positioning within a few centimeters—and under good conditions, around 1 cm—can be achieved. Experiments have confirmed that averaging stationary measurements can reduce errors to the sub-millimeter scale in some cases. Vertical accuracy is also achievable for civil engineering use because elevations are corrected using geoid models. By leveraging RTK-GNSS high-precision positioning technology, accuracy comparable to traditional surveying instruments is assured.

Q: Can non-professional surveyors use it? Is the operation difficult? A: Operation is very simple: just follow the smartphone app’s buttons and on-screen guidance. The UI is designed to be intuitive so that basic operations can be learned through a few hours of training or reading a manual. For example, pile placement guidance displays arrows and distances on the screen, so following the directions leads you to the target point. Point cloud scanning is also automatically performed while walking and viewing the camera. Site staff report comments such as “I could do layouting like a game” and “I was uneasy at first but adapted quickly,” indicating it’s designed as a surveying tool anyone can use.

Q: Can it be used at remote mountain sites with no signal? Does it require Internet access? A: LRTK smartphone surveying supports offline operation. While Internet-based corrections are normally used to receive high-precision positioning corrections, the equipment can also receive augmentation signals broadcast directly by Japan’s satellite positioning system (Michibiki). Therefore, surveying without loss of accuracy is possible at mountain or island sites out of cell coverage. Cloud synchronization and sharing will occur after returning to network coverage, but data can be saved locally on the device in the meantime. The equipment is also designed for outdoor durability such as water and dust resistance (※subject to the smartphone’s durability), so it can be used safely under harsh field conditions.

Q: How can the measured data be used? Can it be imported into existing CAD or software? A: Measured data can be viewed and measured in the cloud and exported in standard file formats. For example, point clouds can be exported in LAS or XYZ formats, and surveyed coordinate points can be output as CSV or DXF for import into typical civil CAD or drawing software. Data include plane coordinates and elevations in the Japanese geodetic system, making it easy to align with other survey results and design data. The outputs meet deliverable requirements such as those in the Ministry of Land, Infrastructure, Transport and Tourism’s “As-Built Management Guidelines” (requirements for 3D survey data and photo management), so they can be submitted directly for electronic delivery or as construction planning materials. In short, data measured on site can be immediately applied to business operations.

Conclusion: LRTK supporting the future of solar construction sites

To achieve both efficiency and quality on solar power plant construction sites, active use of digital technologies is indispensable. The field of surveying and measurement is undergoing dramatic evolution thanks to innovative solutions like LRTK smartphone surveying. The fact that precision surveying that once required specialists can now be performed easily by site personnel has the potential to change the very nature of construction management.

With LRTK smartphone surveying, even vast solar power sites can have detailed data “visualized” and shared among all stakeholders to advance projects. It helps realize a high-level balance of efficiency, quality, and cost, supporting safe and reliable construction. As demand for renewable energy facility construction increases, such digital tools are likely to become key instruments for improving site productivity and workstyle reform. It is no exaggeration to say that the future of solar power construction sites will be supported by technologies like LRTK.

A natural introduction for those considering adoption (simple surveying with LRTK)

If this article has piqued your interest in LRTK smartphone surveying, consider imagining specific use cases as you evaluate adoption. Whether you want to reduce on-site surveying labor or leverage data to enhance construction management, LRTK offers a simple, immediately effective solution. Its ease of starting with just a smartphone is attractive, and you can start with small areas or pilot deployments to experience the benefits.

LRTK-based simple surveying is increasingly being adopted at many construction sites. Beyond solar power plants, it is becoming a driver of “site DX” across civil engineering, facility maintenance, and other fields. Site staff frequently praise it, saying “stress from waiting for surveying has been reduced” and “I can focus on work without carrying paper drawings.” These comments suggest LRTK smartphone surveying is not only a new technology but also has the potential to transform how site work is done.

If you are involved in building solar power plants, why not consider LRTK smartphone surveying as an option? It can be a reliable partner that helps you achieve efficiency and quality while promoting on-site DX.