Centimeter-level surveying with just an iPhone! The power of LRTK that benefits PVsyst simulations

There is a tool indispensable for photovoltaic system design and energy yield prediction called PVsyst. PVsyst is a world-standard software that can simulate power generation with high accuracy by inputting meteorological data and panel layouts. Because it can account for shading from surrounding buildings and trees, it enables predictions that accurately reflect local site conditions. However, to maximize that accuracy you need detailed and precise survey data about the site’s topography and obstacles. This is where LRTK comes in. In this article, we explain in detail how LRTK technology, which enables centimeter-class positioning using only an iPhone, can enhance PVsyst solar power simulations.

The importance of PVsyst simulations and high-precision site data

In power generation simulations for solar plants, the success or failure depends on how accurately you can model site information. In PVsyst, in addition to weather conditions, you can input panel layout, azimuth, tilt angle, and also the effects of shading from surrounding terrain, structures, and trees. For example, if mountains or high ground surround the site you can set their elevation angles as a horizon profile, and nearby trees or utility poles can be modeled as 3D objects to calculate their shadows on the panels. The more precise the input data, the more reliable the simulation results.

In practice, however, obtaining such detailed data is not easy. Traditionally, gaining an understanding of on-site shading required measuring horizon angles with a compass and inclinometer or capturing all-sky photos using a special fisheye-lens camera. To grasp elevation differences in the terrain you would need careful topographic surveys by licensed surveyors or 3D map creation via drone aerial surveys. These conventional methods are time-consuming and labor-intensive, and require specialized equipment and skills. There are also methods that estimate from satellite imagery or existing maps, but they are limited in resolution and timeliness, and often diverge from actual site conditions due to tree growth or newly constructed buildings. As a result, even if you perform precise calculations in PVsyst, inaccurate input data can create discrepancies with reality, risking the failure of otherwise optimized designs.

Thus, high-precision on-site survey data is the key to improving solar power simulation accuracy. If you can capture site topography down to the centimeter and accurately measure the positions and heights of surrounding obstructions, reflecting that in PVsyst will allow you to accurately estimate shading impacts and power losses. Now imagine achieving such surveying with only an iPhone. The solution that makes this possible is called LRTK.

What is LRTK? Centimeter-class positioning enabled by the iPhone

LRTK is an ultra-compact RTK-GNSS receiver that attaches to smartphones (iPhone/iPad). RTK (real-time kinematic) is a positioning technique that corrects GNSS satellite errors to measure position; while typical GPS yields errors of several meters (several ft), RTK can provide positioning with errors of just a few centimeters (cm level accuracy (half-inch accuracy)). The LRTK device is designed so that anyone can easily use RTK positioning by attaching it to an iPhone and launching a dedicated app. It is lightweight and compact—only a few hundred grams—and fits in a pocket. Because the antenna and battery are integrated, you can perform surveying while walking the site without bulky tripods or cables.

Usage is simple. Bring the iPhone (with the attached LRTK receiver) to the point you want to measure and tap a button in the app. The latitude, longitude, and elevation of that point are instantly recorded with centimeter-level precision (cm level accuracy (half-inch accuracy)). Conversions to local geodetic systems like Japan’s plane rectangular coordinate system and calculations that consider geoid height are performed automatically, so the coordinates obtained in the field can be used directly in design drawings. The app also lets you record date/time and notes for each survey point—entering titles or field notes like “southwest corner of planned site” makes later data organization easier.

A notable feature of LRTK is that it can perform positioning even in mountainous areas without network connectivity. Conventional RTK surveying required a mobile data connection to receive correction information from a base station, but LRTK supports correction signals derived from Japan’s Quasi-Zenith Satellite System (such as CLAS), enabling high-precision positioning even where cellular signals do not reach. Since solar plants are often built in mountainous or high-elevation locations, the ability to survey without relying on communications infrastructure is a major advantage.

Recorded positioning data can be uploaded to the cloud and shared immediately. Survey points collected on-site are plotted on a map and can be checked in real time by remote team members. You can also calculate distances and elevation differences between measured points on the spot, eliminating the need to jot everything down in paper field books. With just one iPhone per person, multiple people can divide tasks and efficiently survey large sites. High-precision surveys that used to require professional surveyors or heavy equipment are becoming more accessible thanks to LRTK.

Point cloud data measurement made easy: iPhone LiDAR and LRTK integration

LRTK’s true value isn’t limited to point positioning. The latest iPhones include a LiDAR scanner that captures the surrounding environment as 3D point cloud data. The LRTK app combines this LiDAR capability with high-precision positioning to enable on-site 3D scanning. Simply walk while holding the iPhone and you can progressively capture point clouds of the terrain and structures in front of you. Because LRTK’s RTK-GNSS constantly and precisely tracks the device’s position, the captured point clouds are already tagged with global coordinates (latitude, longitude, altitude). This eliminates the troublesome step of later georeferencing the point cloud.

Traditionally, obtaining 3D point cloud data required expensive terrestrial laser scanners or drone surveys. Even with drones, correcting several meters (several ft) of positional error often required placing multiple ground control points (targets) beforehand and using them to correct the dataset after flight. Aerial surveys also cannot capture point clouds under tree canopies or behind structures that are not visible from above. In contrast, iPhone scanning with LRTK allows people to directly access and measure beneath obstacles and in narrow spaces, so there is less missing data, and distortions in the captured data are corrected in real time, enabling comprehensive and high-accuracy 3D modeling of the existing conditions.

Point cloud data obtained via LRTK scanning can be uploaded to the cloud for immediate use. A dedicated web platform can display point clouds in a browser and enables required measurements without survey CAD software. You can compute distances, areas, and volumes between arbitrarily chosen points, or inspect cross-sections with a single click. For example, it can be used for pre- and post-earthwork volume comparisons across large sites. When constructing a solar power plant you may terrace slopes to create flat land; with LRTK you can capture the existing terrain as point clouds before construction, overlay that with the planned design terrain model, and automatically calculate cut-and-fill volumes, greatly streamlining earthwork quantity calculations that formerly consumed significant time from site supervisors and civil engineers.

Point clouds also capture surrounding trees and structures in detail. This information is useful for detailed shadow analysis in PVsyst. For example, scanning the forest around a site lets you determine the positions and heights of individual trees with centimeter-level error, from which you can derive obstruction angles relative to solar elevation and input them into PVsyst’s “nearby objects” shading fields to accurately estimate seasonal and diurnal generation losses. In practice, you can create a 3D terrain model from LRTK-acquired terrain and point cloud data, place panel layouts on it, and import that into PVsyst to perform advanced analyses such as per-panel shading simulations animated over time. Such simulations rooted in actual site conditions make post-construction performance more predictable and enhance the reliability of investment decisions and design optimization.

Design visualization and construction support via AR features

LRTK also includes features that leverage high-precision positioning for AR (augmented reality). AR overlays virtual objects onto the real-world view on a smartphone screen, and LRTK’s strength is its lack of positional drift. Conventional smartphone AR can suffer from GPS error and gyroscope drift that cause virtual objects to gradually shift from their intended locations. But with RTK precisely tracking device position, LRTK ensures that AR-displayed objects remain fixed at the correct locations no matter how much you move. This is highly useful on construction sites.

One use is visualizing design data. If you load a 3D design model (for example, a power plant layout CAD file or a BIM model) into the LRTK app, you can display that model in AR on-site. For example, a 3D model of the planned solar panel array can be overlaid on the actual site so you can visually confirm the post-construction appearance. This makes it easy to anticipate the visual impact of panel heights and arrangements on the surrounding landscape, aiding neighbor briefings and stakeholder consensus-building. Standing on the planned site and sharing an image of “this is how tall the panels will be here” helps close perception gaps during planning.

Another use is construction efficiency. LRTK’s AR can display virtual markers or stakes at specified coordinates and guide users to those positions. Using this, you can identify stake locations or equipment installation points on-site precisely according to drawing coordinates. Tasks that previously required surveyors to set out points or perform layout work can instead be accomplished by following on-screen arrows, allowing anyone to reach the correct points. Boundary markers obscured by vegetation or survey markers buried under snow can be located by pre-registering their coordinates and displaying them in AR. Even across extensive solar plant sites, LRTK’s guidance enables a single person to efficiently verify reference points and stake locations.

AR is also powerful for inspection and management during and after construction. By overlaying uploaded design data (for example, post-earthwork surface models or equipment layout drawings) from the LRTK cloud with on-site point cloud data, you can color-code deviations between design and as-built conditions. This allows intuitive checks of whether earthworks were completed as designed or whether racks and equipment are installed at the correct positions and heights. If discrepancies are found, you can highlight those areas in AR and take immediate corrective action on-site. Although solar plants are relatively simple structures, they contain many devices spread across wide areas, so manual inspection has limits. Leveraging LRTK enables data-driven smart inspections and helps raise quality control levels.

Benefits of adopting LRTK in renewable energy projects

As described above, LRTK offers a range of useful features across design to construction for solar power projects. The adoption benefits can be summarized as follows.

• Improved simulation accuracy: By reflecting detailed on-site survey data in PVsyst, energy yield predictions become dramatically more accurate. You can plan with shading losses and terrain-induced efficiency variations incorporated precisely, aiding optimization of system capacity and layout.

• Reduced surveying cost and time: Traditionally, you needed to commission survey companies or plan and obtain approvals for drone flights, which took time. With LRTK, personnel can collect necessary data quickly with an iPhone. No heavy equipment transport or battery swaps are required, and one person can work efficiently across large sites. This shortens lead time to planning and accelerates overall project schedules.

• Enhanced on-site design accuracy: Using point cloud data to inform design enables terrain-aware planning, reducing excess or insufficient earthworks and placing panels in areas with optimal insolation. Reducing discrepancies between design and the actual site lessens rework and prevents “this wasn’t expected” surprises later.

• Improved construction quality and safety: AR-guided stake placement and as-built checks help prevent construction and surveying errors. Reducing manual layout work lowers worker burden and human error. Because LRTK enables remote surveying and guidance even in steep or difficult terrain, it also reduces the need for people to enter hazardous areas.

• Faster information sharing and decision-making: Data captured with LRTK can be shared to the cloud immediately, allowing field survey results to be reviewed in real time by headquarters or design teams. Decisions and discussions can be based on live data, speeding up decision-making. AR-based visualization of the finished image also helps nontechnical stakeholders reach a common understanding, smoothing consensus building.

Conclusion: Next-generation field surveying starting with just an iPhone

In the world of PVsyst-based solar power simulations, the accuracy of on-site data is a decisive factor in simulation accuracy. The solution of centimeter-level surveying using an iPhone and LRTK can truly be called a game changer. By adopting LRTK, which combines ease of use and high precision, on-site surveying and point cloud acquisition that once required specialists can become part of everyday operations, improving quality and speed across all phases of renewable energy projects.

From planning through construction and operation, LRTK bridges field-oriented realism and digital technology. Now that “centimeter-level surveying with just an iPhone” is a reality, there’s no reason not to use this technology. Leverage LRTK to experience precise simulations based on field data and smarter construction management on your next project. Start the new era of surveying with a single iPhone and aim for further leaps in renewable energy projects.

For details and implementation of LRTK Phone, information is also available on the official website. If you’re interested, please also visit the [LRTK product page](https://www.lrtk.lefixea.com/lrtk-phone).