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

Introduction: What "efficiency" means on solar power construction sites

Efficiency is always required at solar power plant construction sites. Large-scale installation of solar panels covers wide areas, and completing work within short construction periods is important from a business standpoint. With limited personnel arranging many solar panels in mountainous areas or on 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 also grown. At the same time, labor shortages and the aging of skilled workers have progressed, and methods that rely on site-specific experience can no longer cope efficiently.

So what does "efficiency improvement" specifically mean at solar power construction sites? It does not simply mean rushing work, but rather eliminating unnecessary effort and waste and progressing processes accurately and smoothly. The ideal is to reduce rework and surveying errors and to get construction right the first time. Smooth information sharing between the site and the office, minimizing waiting times and communication loss, also contributes to improved efficiency. One key to realizing such efficiency improvements is the use of digital technology. In particular, in the field of surveying—which forms the foundation on construction sites—new smartphone-based solutions are poised to dramatically change site efficiency.

The role of surveying in the construction process of solar power plants

Surveying plays an important role supporting the design and construction process of solar power plants. While surveying is often thought of as work performed by specialized technicians, surveying data is used in many phases from planning to completion at solar power plants. Surveying is involved in phases such as the following.

• Pre-design site investigation: This is the stage of grasping the topography of potential plant sites. Accurately measuring site elevation differences, slopes, and surface undulations helps in planning panel layouts and earthworks (cut-and-fill plans). Traditionally, surveyors measured many points using transits or GPS instruments to create topographic maps.

• Marking and stake-driving at the start of construction: This involves marking positions on site to drive stakes or indicate earthwork extents as determined on design drawings. In solar panel construction, which requires positioning many stakes and supports, experienced survey personnel calculate dimensions from drawings and place stakes or markers on the ground. This takes manpower and time, and mistakes can cause array misalignment and other issues.

• In-process verification during construction: Surveying during earthworks or foundation work to confirm whether the work is proceeding according to design. For example, checking whether the ground has been leveled to the specified height, 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 record-keeping at completion: After construction, inspect and record whether the completed plant equipment matches the design drawings. Although solar power plants may not have as strict as-built control standards as civil engineering structures, measuring the formed terrain and the positions and elevations of installed structures helps with future maintenance planning and registration in land records.

Surveying data therefore provides an essential information foundation at each stage of design, construction, and maintenance of a solar power plant. Conversely, delays or low accuracy in surveying can affect the entire subsequent process. For example, insufficient initial topographic surveying can lead to design errors, and during construction you may discover "the slope is steeper than planned" or "fill is insufficient." If stake positions are mislocated, panel rows may be skewed or conflict with adjacent equipment. Thus, rapid and accurate surveying is crucial to construction efficiency and quality at solar power plants.

Impact of visualizing terrain data

In recent years, the construction industry has been moving toward visualizing site topography and construction conditions as digital data. What used to be understood via paper drawings and site photos can now be visualized with rich data such as 3D models and point clouds. Solar power construction is no exception, and digitizing terrain brings many advantages.

First, visualizing terrain data deepens common understanding among stakeholders. For example, designers can review 3D terrain models on a PC while considering layouts. Because they can intuitively grasp undulations and slopes, they can accurately decide, for instance, "cut this hillside to level it" or "avoid this area prone to shading." For site supervisors and construction managers, a visual terrain model is easier to grasp intuitively than numeric reports, enabling more accurate instructions.

Digitizing terrain also helps optimize construction planning. For example, by comparing pre-construction terrain data with post-construction design data, you can simulate where and how much to excavate or fill. You can calculate required earth volumes in advance and efficiently arrange dump trucks and disposal plans for excess soil. Since solar panel output is affected by solar incidence angle, you can run seasonal shadow simulations using terrain models and fine-tune panel placement. When data is visible, decisions that previously relied on experience can be made scientifically and quantitatively.

Furthermore, visualization of terrain and construction data is powerful for record-keeping and verification. Accumulating drone aerial images and 3D scan data taken during construction creates a digital record to review when and where work occurred. If subsidence or defects are found after construction, comparing current conditions with earlier terrain data helps identify causes and plan repairs. In this way, visualizing the site as data provides major benefits for both construction efficiency and quality control.

What is point cloud data? Features and benefits

A commonly used data format for 3D visualization of terrain and structures is point cloud data. A point cloud is a set of many points with spatial position information that represents the surface shape of an object with countless points. For example, when surveying terrain with a laser scanner, data is obtained as a dense cluster of points on the surfaces of hills and valleys. Plotting this cluster (the point cloud) makes it look as if the terrain itself has been reproduced in three dimensions.

The main feature of point cloud data is that it contains very detailed 3D information. Each point has X, Y, and Z coordinate values (and sometimes color or reflectance intensity), recording details down to small features of the ground or structures. Complex shapes that cannot be fully represented in conventional plan views or numerical data can be preserved in a point cloud as a "mass of points," allowing you to take arbitrary cross-sections or measure dimensions later. It is truly like a digital copy of the actual site.

There are many advantages to using point cloud data at solar power sites. First, a single measurement can capture an enormous number of measurement points, reducing the risk of missing data like "I should have measured that spot’s elevation." Required information can be extracted from the point cloud later, reducing re-surveying. Second, point clouds are visually intuitive: surface irregularities appear as point density and distribution, making differences easy to understand even for non-experts. Third, recent software and cloud services have made point cloud handling easier, allowing you to freely rotate and zoom 3D point clouds on a PC and perform automatic volume calculations or comparisons—creating an environment where data utilization is straightforward.

However, traditional point cloud acquisition required expensive 3D laser scanners or drone imaging equipment and often needed specialist operators, posing a barrier for small sites. In recent years, advances in camera and sensor technology have made more accessible point cloud acquisition methods possible. One of these is point cloud measurement using a smartphone. Next, we will look at how LRTK surveying completed with only a smartphone works and what strengths it offers.

How LRTK smartphone surveying completed with only a smartphone works and its strengths

LRTK smartphone surveying, which has recently attracted attention, uses a small device attached to a smartphone and a dedicated app to allow anyone to easily perform high-precision surveying that previously required specialized equipment. "LRTK" is a proprietary solution that builds on Real-Time Kinematic positioning and, when combined with a smartphone, achieves centimeter-level positioning accuracy (cm level accuracy (half-inch accuracy)). Concretely, a slim RTK-GNSS receiver attached to the smartphone calculates satellite position information with high precision and provides position coordinates to the smartphone app in real time. This enables the smartphone to determine its current position with accuracy comparable to conventional surveying instruments.

A major characteristic of LRTK smartphone surveying is that it not only measures current position but also integrates with the smartphone camera and sensors to easily capture 3D data of the site. By launching the dedicated app and pointing the camera while walking, you can record the surrounding terrain and structures as point cloud data. This combines smartphone-built-in LiDAR (optical distance measurement) or image analysis (photogrammetry/SfM techniques) that reconstruct shapes from camera images with LRTK’s high-precision self-positioning. Standalone smartphone AR scanning previously suffered from coordinate drift as you walked, but LRTK constantly corrects global coordinates via GNSS, enabling stable measurements where the point cloud does not distort even over long distances.

The point cloud data obtained in this way is tagged from the start with absolute coordinates like latitude, longitude, and elevation. That means when you later overlay this data on CAD drawings or other geographic information, it aligns precisely. Usually, creating point clouds from drone images requires alignment using ground control points, but LRTK smartphone surveying produces correctly georeferenced data on-site immediately, which is revolutionary. Obtained point clouds and coordinate data can be uploaded to the cloud from the smartphone with one click and shared and viewed instantly on an office PC. There is no need to install dedicated PC software; you can rotate and measure 3D point clouds in a browser and overlay them on drawing data. This facilitates "speed management," allowing stakeholders to confirm the site-measured data the same day and use it for decision-making.

Summarizing the strengths of LRTK smartphone surveying:

• Portability and ease of use: Since it only requires a smartphone and a palm-sized receiver, you don’t need to carry heavy tripods or equipment. Site workers can carry it in a pocket and measure immediately when needed.

• Single-operator work: Surveying and marking tasks that used to require two people can be performed by one person with a smartphone. The smartphone screen provides guidance so that no assistant is needed to accurately lay out positions.

• Multifunctionality: One device can handle a wide range of tasks—recording survey points, point cloud scanning, marking guidance, photo documentation, and AR display. For example, you could scan terrain in the morning, compare design drawings with the same data in the afternoon, and display stake positions in AR for marking in the evening—all on the same device.

• High accuracy: RTK-GNSS improves position accuracy from the several meters (several ft) errors of typical smartphone GPS to several centimeters (several in). Experiments show horizontal position errors of about 1-2 cm (0.4-0.8 in) in single-epoch positioning, and by time-averaging it can achieve accuracy of less than 1 cm (less than 0.4 in). Experiments have also confirmed that averaging stationary positions can keep errors to the millimeter level (about 0.04 in). Vertical heights are converted to actual elevations using geoid correction, providing sufficient accuracy for civil engineering works.

• Real-time AR utilization: Because of the high accuracy, overlaying design data onto the real world through the smartphone screen shows minimal offset, enabling intuitive on-site verification. For example, you can project the designed finished surface onto the ground in AR to display in color "how much more soil needs to be removed," or place virtual stakes to visualize stake positions. Digitizing aspects that previously depended on craftsmen’s intuition lets anyone perform tasks correctly without misunderstanding.

• Offline support: LRTK receivers support not only internet-based correction but also centimeter-level augmentation information (CLAS) broadcast by Japan’s quasi-zenith satellite "Michibiki." Therefore, even at sites without mobile reception, such as mountainous areas, the receiver can receive satellite correction signals and continue positioning. For remote solar power plant construction, surveying will not stop just because the site is out of range. Data can be stored on the device and synchronized later when connectivity is available. The equipment itself is built to be water- and dust-resistant (subject to the smartphone’s durability).

• Low-cost adoption: Although we will not go into detail here, initial costs can be lower compared to purchasing expensive dedicated equipment. It is realistic to equip many workers with one device each, and the price point makes LRTK an easy tool for promoting DX across an organization.

On-site use cases (pre-formation / during construction / as-built management)

Here are concrete scenes in which LRTK smartphone surveying is used on solar power sites, following construction progress.

• Pre-formation (pre-construction survey): Before work begins, you can quickly measure site topography with smartphone surveying. Walking the planned area while scanning the ground captures elevation differences and terrain shapes as point cloud data. Designers can use this data to prepare optimal layouts and earthwork plans. For example, estimating cut-and-fill volumes accurately before starting prevents excess or shortage of earthwork during construction, reducing costs. If you overlay the existing terrain and design model on the cloud in advance and run simulations, you can detect issues early—such as "the northern panels will be shaded by the slope"—and easily revise designs. Processes that used to take several days to weeks from initial survey to design incorporation can start design reviews the same day by sharing terrain data acquired with LRTK.

• During construction (progress management and stake-driving guidance): LRTK smartphone surveying is useful during earthworks and stake-driving phases. For example, after a bulldozer levels the ground, simply walking the site with a smartphone obtains a point cloud of the finished ground. Comparing it with the planned ground elevation in the cloud makes it immediately clear whether the site has been leveled to the specified height. Low or overly high fill areas are color-coded, enabling precise additional instructions to operators. For stake-driving, importing the design stake coordinate data into the app allows the smartphone to guide workers like a car navigation system to the correct locations. The screen shows guidance like "0.1 m (0.3 ft) east, 0.05 m (0.16 ft) north to the target point," and switching to AR mode places virtual arrows or stake markers on the camera image to indicate where to drive stakes. This enables less experienced staff to pinpoint stake locations without confusion, allowing site staff without surveying expertise to complete stake layout work themselves. In actual sites, use cases have been reported where geotagged photos were stored in the cloud beforehand, enabling accurate navigation to repair locations using those photos. The ability to measure and check instantly in various on-site situations greatly reduces process loss.

• As-built management (completion inspection and record-keeping): At project completion, LRTK makes it easy to create 3D as-built records of the completed terrain and structures. Scanning the entire finished site yields a detailed point cloud of the final ground surface. Comparing this to the design data makes it possible to inspect the entire site for conformity. Areas filled beyond tolerance or insufficiently excavated are automatically highlighted in color, making points requiring rework immediately apparent. For large solar sites, combining drone imaging or LRTK-equipped drones (large-scale solutions) can cover the whole site quickly, with detailed areas supplemented by walking scans. As-built point cloud data can be organized as deliverables for electronic submission or used as shared documentation, improving the efficiency of inspection document preparation. Storing these 3D as-built data also serves as an asset for lifecycle management of the plant, allowing accurate reconstruction of the past state for future expansion or inspection work.

Implementation effects: impact on construction efficiency, quality, and cost

What concrete effects can be achieved by introducing LRTK smartphone surveying? Here we summarize the impact in terms of the main points: construction efficiency, quality, and cost.

• Improved construction efficiency: Surveying and marking work time can be significantly shortened compared to traditional methods. Tasks that previously required multiple people and a half-day can be completed by one person within a few hours, for example. Because measurements can be taken whenever needed, waiting time loss is reduced. Site supervisors can check without waiting for a surveying team, resolving bottlenecks across the schedule. Cloud sharing reduces the work of preparing reports from site to office and compresses man-hours for data organization and drafting drawings. As a result, effects manifest as shortened schedules and increased productivity, enabling more projects to be completed with limited time and personnel.

• Improved quality: High surveying accuracy and frequent checks improve construction quality. For example, keeping stake positioning errors within a few centimeters increases panel alignment accuracy and reduces undue strain on wiring and connectors. In earthworks, constant leveling along design cross-sections prevents leaving low spots where water pools and avoids wasteful overfilling. Repeated real-time measurement and verification during construction reduce rework and standardize finish accuracy. Combining photos with point clouds enables detailed traceability of construction conditions later, raising the level of quality assurance and troubleshooting. LRTK smartphone surveying thus contributes not only to faster work but to getting it right, forming the foundation for high-quality solar power plants.

• Cost reduction: Improvements in efficiency and quality ultimately reduce costs. Labor costs decrease as the number and hours of personnel engaged in surveying are reduced. Outsourced surveying expenses can be cut if performed in-house. Reduced rework lowers wasted material and equipment operation costs. Shorter schedules reduce site maintenance expenses (site offices, security, temporary facilities), and earlier power generation reduces opportunity loss of electricity sales. The equipment itself is more affordable than large laser scanners or dedicated survey instruments, and training costs are lower. Overall, introducing LRTK smartphone surveying is a highly cost-effective investment.

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

Finally, we summarize common questions from site personnel about LRTK smartphone surveying in a Q&A format.

Q: Can smartphone surveying really achieve centimeter-level accuracy? A: Yes. In environments where satellites can be received properly, horizontal positioning can be within a few centimeters, and under good conditions it can reach about 1 cm. Experiments have confirmed that averaging stationary positions can reduce errors to the millimeter level (about 0.04 in). Vertical height corrected by geoid models yields actual elevations suitable for typical civil surveying and stake-driving. LRTK uses high-precision RTK-GNSS positioning technology, ensuring accuracy comparable to conventional surveying instruments.

Q: Can non-specialist operators use it? Is the operation difficult? A: Operation is very simple: follow the smartphone app prompts, press buttons, and move according to on-screen guidance. The UI is designed to be intuitive so that basic operations can be learned in a few hours of training or by reading a manual. For stake-driving guidance, the screen displays arrows and distances, so following the instructions gets you to the target point. Point cloud scanning is automatically captured while walking and viewing the camera. Site staff report comments like "I could do the positioning like a game" and "I was worried at first but quickly got used to it." The system is designed as a surveying tool anyone can use.

Q: Can it be used at remote mountain sites without cellular reception? Is an internet connection required? A: LRTK smartphone surveying supports offline use. Normally correction information for high-precision positioning is received via the internet, but in areas without mobile reception the device can receive augmentation signals directly from Japan’s satellite positioning system (Michibiki). Therefore, surveying at remote or island solar site locations is possible without loss of accuracy. Of course, cloud synchronization and sharing occur after returning to an area with reception, but data can be stored locally on the device in the meantime. The equipment is designed for outdoor durability (subject to the smartphone’s durability).

Q: How can measured data be used? Can it be imported into existing CAD or software? A: Measured data can be viewed and measured directly in the cloud and exported in standard file formats. For example, point clouds can be exported as LAS or XYZ files, and measured coordinate points can be exported as CSV or DXF for import into the civil CAD or drafting software you normally use. The data is tagged with Japan’s geodetic coordinate system and elevations, so aligning with other survey results and design data is easy. It also supports the deliverable requirements (3D survey data and photo management) specified in ministry guidelines such as Japan’s Ministry of Land, Infrastructure, Transport and Tourism “As-Built Management Guidelines,” making the data suitable for electronic submission or explanatory materials. In short, field-measured data can be put to immediate use in office workflows.

Conclusion: LRTK supporting the future of solar construction sites

To achieve both efficiency and quality improvement at solar power construction sites, active use of digital technology is essential. Surveying and measurement are fields undergoing dramatic evolution thanks to innovative solutions like LRTK smartphone surveying. Precision surveying that once required specialists can now be performed easily by site personnel, which has the potential to fundamentally change construction management.

With LRTK smartphone surveying, you can visualize data across vast solar sites down to the smallest details and share it among all stakeholders while advancing the project. It helps achieve a high-level balance of efficiency, quality, and cost, supporting safe and reliable construction. As demand for renewable energy infrastructure increases, such digital tools will become key drivers of productivity improvement and workstyle reform on sites. It is not an 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 (simplified surveying with LRTK)

If this article has sparked your interest in LRTK smartphone surveying, consider evaluating its adoption while imagining concrete use cases. For needs such as reducing site surveying labor or leveraging data to enhance construction management, LRTK offers a simple and immediately effective solution. The ease of starting with just a smartphone is attractive, and you can begin with small plots or pilot deployments to experience the benefits.

LRTK simplified surveying is already being adopted on many construction sites. It is not limited to solar power plants but is contributing to "site DX" across civil engineering and maintenance fields. Site staff report that "stress from waiting for surveying has decreased" and "we can focus on work without carrying paper drawings," indicating positive feedback. As these voices show, LRTK smartphone surveying is more than just a new technology—it has the potential to transform how work is done on site.

If you are involved in solar power plant construction, consider LRTK smartphone surveying as an option. It can be a reliable partner for achieving efficiency and quality improvements while promoting DX on site.