SMART ENERGY WEEK: Refining Construction Plans with High-Precision Positioning for Solar Panel Installations

In the renewable energy industry, the importance of high-precision positioning for solar panel installation sites is receiving renewed attention. At events such as the Smart Energy Week trade show, improving construction planning through digital technologies is a major theme. By increasing surveying accuracy at installation sites, it is possible to refine construction plans and consistently improve project quality from the planning stage through operation. This article explains in detail the importance of surveying for solar panel installation and the concrete benefits of using high-precision positioning (RTK/CLAS, etc.) for each process stage.

The Importance of Surveying in Solar Panel Installation

In solar power installation projects, accurate on-site positioning and surveying are the key to success. From rooftops to large-scale mega-solar farms and agrivoltaics (solar sharing for farming), surveying accuracy affects the entire project in every case. Below are the main important points of surveying for solar panel installation.

• Minimizing the impact of shadows: Solar panels are sensitive to shading; even slight shadows can significantly reduce power generation. Accurate surveying allows you to understand the positions and angles of shadows cast by surrounding buildings and trees and to adjust panel layouts accordingly. Precise positioning is indispensable for setting row spacing and tilt angles so that panels do not cast shadows on each other. For layout optimization that takes into account winter solar altitude and terrain undulations, millimeter-level measurement data (mm (about 0.04 in) level) can be useful.

• Ensuring construction accuracy and quality: To install panels and racks according to drawings, the positions of foundations and piles must be determined precisely. If positioning is off, bolt holes may not line up during rack assembly or panels may end up uneven, affecting construction quality. By establishing reference points through high-precision surveying, on-site errors can be minimized and all panels can be supported by a stable structure. As a result, the risk of post-construction defects is reduced.

• Layout optimization and land-use efficiency: Accurate on-site dimensions and elevation data directly enable layout designs that make maximum use of the site. Designing with low surveying accuracy can leave wasted margins or cause unexpected conflicts. By understanding the site shape to the centimeter level (cm (about 0.4 in)), you can optimize panel placement and tilt to suit the terrain, achieving the maximum generation capacity on limited land.

• Boundary confirmation and regulatory compliance: Panel placement must not violate land boundaries or building regulations. Incorrect surveying that leads to installation beyond property boundaries can cause disputes with neighbors or legal problems. High-precision surveying to correctly identify land boundaries and set-backs (distances from boundaries) ensures panels remain within permitted areas and allows construction to proceed with confidence. It also enables accurate identification of areas to avoid, such as power lines or underground utilities.

• Avoiding environmental and surrounding impacts: The local natural environment and terrain conditions around the site can be accurately understood through precise surveying. For example, detailed measurement of slope and drainage conditions within the site makes it possible to design layouts that avoid areas at risk of erosion or puddling. If valuable trees or protected ecological areas are nearby, panel placement can be adjusted based on high-precision location information to minimize environmental impact.

Thus, improving surveying accuracy underpins solar power projects and is an extremely important factor. Next, let’s look at the concrete benefits obtainable by utilizing high-precision positioning technologies.

Construction Benefits Brought by High-Precision Positioning Technologies

High-precision positioning technologies such as RTK and CLAS, which have become widespread in recent years, dramatically reduce GPS satellite positioning errors and enable centimeter-level positioning. RTK (Real Time Kinematic) enhances positioning accuracy using correction information from a base station, while Japan’s quasi-zenith satellite system “Michibiki” provides CLAS (a centimeter-level positioning augmentation service) that distributes wide-area correction data from satellites. By using these, GPS positioning that once commonly exhibited errors of several meters can be reduced to errors within a few centimeters. The main benefits of adopting high-precision positioning on site are as follows.

• High-precision installation positioning: You can precisely identify installation points for each panel and pile, faithfully reproducing plans on site. There is reassurance that foundation work requiring no more than a few centimeters of deviation, or rail installation on rooftops, can be carried out at the positions designed. This prevents cumulative placement errors and results in a neat overall solar power installation.

• Reduced shadow risk: High-precision positioning maintains the row spacing and placement angles assumed in simulations, minimizing the risk of shading from adjacent panels or surroundings. Especially on sloped or complex terrain, small deviations can cast significant shadows at certain times, but precise positioning reproduces planned simulation results and prevents generation losses.

• Improved design accuracy: Incorporating high-precision on-site survey data into design improves the accuracy of generation forecasting simulations. Using detailed terrain models and obstruction data based on actual measurements allows planning that accurately incorporates, for example, annual irradiance variability and seasonal shadow movements. When design and construction match closely, post-completion generation performance approaches planned values and investment return forecasts become more reliable.

• Shorter construction periods and greater efficiency: Introducing high-precision positioning greatly shortens the time required for surveying and stakeout work. Surveys that used to require two to three people for several days can, in some cases, be completed quickly by a single person. Reducing rework due to construction mistakes shortens overall construction time, cutting labor costs and opportunity losses. Faster completion also contributes to earlier power generation and revenue.

• Legal consistency and accurate records: With high-precision surveying data stored electronically, the accuracy of construction records improves. Managing the precise coordinates of each panel and facility digitally provides reliable documentation for audits and permit submissions. High-precision positioning records serve as evidence that installations were carried out “as designed” for farmland conversion permits and other notifications. Accurate as-built data also facilitates planning for future expansions or equipment upgrades.

As described above, high-precision positioning technologies such as RTK/CLAS are powerful means to raise the quality, efficiency, and reliability of solar power installations. Next, we will look at how high-precision surveying is specifically used in each project phase (pre-construction, during construction, and operation).

Pre-construction Phase: Detailed Planning via High-Precision Surveying

In the early pre-construction phase of a project, site surveys and planning are the primary tasks. Introducing high-precision surveying in this phase enables more refined planning and risk reduction.

First, to accurately grasp the current condition of candidate sites, conduct topographic surveys using high-precision GNSS or drone surveying. For vast mega-solar sites, what once required survey teams to walk for days measuring elevations and distances can now be accurately obtained in a short time using RTK-capable GPS receivers. By digitizing ground undulations, existing structures, and tree positions to the centimeter level (cm (about 0.4 in)), you can fully understand a site’s potential and constraints.

Layout design based on precise survey data enables optimal panel placement following the site’s shape. For example, when arranging panels along property boundaries, knowing the boundary line to within a few centimeters allows you to utilize effective area to the limit. If terrain slopes are known, rack heights and step placements can be optimized at the planning stage, and earthwork arrangements can be properly scheduled. With accurate surrounding building and tree positions and heights, annual shadow simulations can be run in software to produce layouts that are less prone to shading.

In the pre-construction phase, environmental assessments and coordination with stakeholders are also required. Precise survey maps provide a common understanding among stakeholders, facilitating specific discussions such as “this is the construction area” or “this tree will be retained.” Attaching detailed drawings to applications to local governments helps smooth permit acquisitions.

Overall, high-precision surveying before construction plays the role of dramatically increasing the accuracy and persuasiveness of initial plans in solar projects, where it is often said that the outcome is decided at the first planning drawings.

Construction Phase: Ensuring On-Site Work with High-Precision Positioning

During actual construction, the key is stakeout work to install equipment and materials according to design. High-precision positioning is also extremely effective here. Traditionally, stakeout for hundreds to thousands of piles and racks across large sites was performed by survey teams using tape measures and transits. Manual stakeout inevitably led to accumulated errors and marking loss (marks fading or being lost).

Combining high-precision positioning with digital devices has made it possible for anyone to accurately identify pile locations. For example, a worker carrying a smartphone equipped with a small RTK-capable GPS receiver can walk around a wide site and reproduce the coordinates from the design drawing on the spot. Following maps or AR markers displayed on the phone screen, workers can reach a stakeout point with pinpoint accuracy based on guidance like “move x cm north.” Even without complex surveying knowledge, workers can find pile locations with a navigation-app-like experience, allowing less experienced staff to maintain construction accuracy.

This smartphone-guided stakeout drastically reduces rework from construction errors. Even a single misplaced pile can cause spacing errors with adjacent panels or bolt-hole misalignments in racks. If high-precision positioning allows all piles to be installed in the correct positions at once, unnecessary re-drilling and delays are avoided, reducing extra costs and improving site productivity.

Furthermore, high-precision positioning data can be shared to the cloud in real time. If the coordinate information of installed positions recorded on site is instantly shared with the office, as-built confirmation and form generation can be done quickly. Accumulating digital data from the construction phase simplifies preparing completion documents and ensures excellent traceability for quality control.

Additionally, integration with AR (augmented reality) technology is being used on construction sites. By overlaying design information onto live camera views on smartphones or tablets, it is possible to verify on the spot whether design and construction are aligned. For example, displaying the intended rack position and angle as an AR overlay makes deviations immediately detectable and correctable. These real-time verification methods suppress variability in construction quality and enable accurate work from the first pass.

Operation and Maintenance Phase: Long-Term Operation Supported by Precise Data

Even after a solar plant begins operation, data from high-precision positioning provides value in operation and maintenance. Long-term stable operation requires periodic inspections, maintenance, and occasional repairs, and the precise initial surveying information is useful in these activities.

If the facility layout is managed digitally at centimeter accuracy (cm-level, about half-inch accuracy), inspectors can accurately identify locations to be checked during routine inspections. Even for mega-solar sites with tens of thousands of panels, if each panel or string’s coordinates and ID are linked in advance, inspections can be conducted efficiently without omissions or duplication. If an abnormal panel is detected, accurate location information enables rapid site localization and reduces repair or replacement time.

High-precision location information is also powerful when integrated with drone inspections and monitoring systems. When a drone equipped with an infrared camera captures an anomalous panel, accurately correcting the drone’s GPS coordinates makes it easy for ground staff to find the corresponding location. Comparing terrain and environment data obtained during surveying with actual generation monitoring results enables analysis of causes, such as “this section has uneven irradiance.” For example, if generation decreases due to the growth of nearby trees over the years, comparing with initial survey data can detect the change and support decisions on proper tree trimming or equipment relocation.

When expanding or replacing equipment, the original high-precision survey data becomes the starting point for design. If you add panels to a site in operation, precise position and height information of existing equipment allows planning of interference-free additions. In repowering—replacing aging panels with higher-efficiency units—the original survey coordinates make planning exchanges easier.

Above all, using high-precision data during the operation phase contributes to increased assurance and reliability. In disasters or failures, a precise equipment map enables prompt response. Accurate site conditions are easier to share among stakeholders, facilitating remote support or objective explanations for insurance claims based on location information.

In this way, using high-precision survey data across the entire lifecycle, including post-construction, is expected to enable long-term efficient operation and trouble reduction of solar power facilities.

Introducing Easy High-Precision Surveying Using LRTK

We have seen the benefits of high-precision positioning at each project stage, but historically the barrier to introducing the necessary surveying equipment was high. Professional GNSS receivers and surveying equipment are expensive and complex to handle, and many situations required dependence on specialists. A solution that has emerged to break this situation is the easy RTK surveying device “LRTK” that uses smartphones.

LRTK realizes a pocket-sized surveying instrument by using a compact high-precision GNSS antenna receiver together with a smartphone. Simply attach the dedicated device to an everyday smartphone and launch the app, and centimeter positioning that used to require equipment costing millions of yen becomes possible. Also called smartphone RTK, this approach envisions each field staff member having a high-precision positioning tool at hand so surveying and stakeout can be done whenever needed.

For example, using LRTK you can obtain and use consistent high-precision position information from pre-construction ground surveys to construction stakeout guidance and operation-phase equipment inspections. The app automatically handles complex coordinate transformations and device operations, so even non-experts can master it with a few hours of training. Cloud integration enables real-time data sharing between site and office, allowing survey results to be immediately reflected in design revisions and construction management.

Such smartphone-based high-precision surveying solutions are rapidly advancing the digitalization and labor savings of surveying in the solar industry. Detailed layouts and fast construction that were difficult with traditional methods are becoming feasible through the spread of technologies like LRTK. Why not leverage these new technologies, which attract attention at industry events like Smart Energy Week, to advance your project’s construction planning to a higher level of accuracy and efficiency? With efficient surveying and reliable construction, you can maximize the value of your renewable energy business.