Improved Accuracy in Solar PV Design: Strong PVsyst Support with iPhone × LRTK

In designing solar PV plants, accurately understanding the site terrain and shading conditions is crucial. PVsyst is a representative software that can simulate a solar power system’s energy output and the effects of shading, and the accuracy of its input data greatly influences the reliability of analysis results. In recent years, methods that combine smartphones with the latest technologies have emerged, enabling field surveys to be conducted more easily and with higher precision than before. This article explains how integrating high-precision terrain, shading, and structure data obtained via iPhone and LRTK surveys into PVsyst analyses can significantly improve design accuracy and work efficiency. We will walk through the challenges of traditional surveying and modeling, the advantages of LRTK, on-site usage, the data import workflow, and how to reflect the results in design. At the end of the article, we also introduce a simple smartphone-only survey using LRTK.

Challenges in traditional surveying and modeling

In solar PV plant design, surveying and 3D modeling are first conducted to understand the site’s terrain and surrounding obstructions (such as structures and trees). However, conventional methods have many challenges. Terrain surveying typically requires expensive, bulky equipment such as total stations or GNSS receivers, and skilled surveyors must collect many points on site. Drone photogrammetry has also become common, but long flights are difficult due to battery limits, and preprocessing is time-consuming—for example, measuring control points (GCPs) in advance for georeferencing. Ground-based laser scanners are another option, but those systems are costly and require specialized operation skills. In heavily forested sites, aerial imagery may not reveal the ground surface, preventing acquisition of terrain data beneath tree canopies.

Because these approaches require significant cost and time to obtain detailed 3D point cloud data, early-stage designs may sometimes proceed without sufficient information. Missing subtle terrain undulations or small obstructions around the site—such as utility poles or trees—can cause discrepancies between PVsyst simulations and actual performance. Solar panels can experience reduced output across an entire circuit even if only part of a string is shaded, so accurately estimating shading impact is essential. For example, if trees that cast long shadows in winter are not reflected in the model, the energy yield may be overestimated. Conversely, designing overly conservatively due to shading concerns—by reducing installed capacity or increasing array spacing—can reduce the plant’s profitability. In short, uncertainties in conventional surveying and modeling have constrained design accuracy and efficiency.

High-precision field surveying with iPhone × LRTK

A cutting-edge solution to these challenges is mobile scanning using smartphones. Specifically, this method combines the iPhone’s built-in LiDAR sensor with high-precision GNSS RTK (Real Time Kinematic) positioning to 3D-scan sites, enabling detailed point cloud collection without specialized equipment. iPhone models from the 12 Pro onward include LiDAR capable of measuring distances up to around 5 meters, allowing capture of surrounding shapes as point clouds. However, LiDAR scans from a smartphone alone do not include georeferenced position coordinates (latitude, longitude, elevation), so traditional surveying required post-processing to align point clouds with map coordinates. By combining RTK centimeter-level positioning, accurate location information can be attached to smartphone-scanned point clouds immediately, enabling integration of multiple scans into precise 3D models even across large sites. Regular GNSS positioning typically has errors on the order of meters, but RTK can improve accuracy to the order of centimeters.

LRTK is a representative solution that realizes smartphone × RTK surveying. It consists of a small RTK-GNSS receiver (with built-in antenna) that attaches to an iPhone and a dedicated app, allowing anyone to perform centimeter-level positioning and 3D scanning with single-handed ease. The app UI is intuitive and easy to use, enabling immediate on-site utilization without specialized training. Even in remote mountain areas or places outside cellular coverage, RTK compatible with augmentation services such as Michibiki’s CLAS (centimeter-class augmentation service) enables stable high-precision positioning. Acquired data can be saved and shared to the cloud on the spot, and point clouds can be reviewed on the smartphone during the survey. The iPhone thus becomes an all-purpose surveying device comparable to traditional instruments, bringing a revolution to time- and cost-intensive conventional methods. Smartphone × RTK 3D measurement methods are gaining attention in the construction and surveying industries and may become the mainstream new surveying approach that does not rely on specialized equipment.

Using LRTK for on-site surveys of solar PV plants offers the following benefits:

• High-precision 3D data: RTK allows acquisition of three-dimensional terrain and structure data with centimeter-level accuracy, enabling comprehensive capture of on-site information required for design.

• Streamlined surveying and design: Surveys can be completed with only a smartphone and a small device, eliminating the need to arrange specialist contractors or heavy equipment, so you can move from field survey to design reflection in a short time.

• Capability for challenging sites: In urban areas, mountainous regions, or beneath tree canopies where drones struggle to fly, walking scans can capture complete point cloud data without omissions.

• Intuitive and safe operations: Real-time point cloud visualization on the smartphone prevents missed areas and avoids taking equipment into hazardous locations.

• Immediate use of digital data: Because coordinates are attached to acquired data, no positional alignment is required in post-processing, and the data can be imported directly into design software. Distances and heights can be measured immediately from the field-acquired point cloud to assist layout planning.

On-site iPhone × LRTK surveying workflow

Below is the basic flow for conducting smartphone surveying using LRTK on site.

• Prepare equipment and app: Before surveying, attach the LRTK device to the iPhone and launch the dedicated app. Configure correction information over the network (e.g., NTRIP) so that RTK centimeter-precision positioning is available. (In areas without cellular coverage, the device receives corrections via supported satellite augmentation services.)

• Start LiDAR scanning: Begin measurement with the app’s 3D scanning function, holding the iPhone and walking around the site to scan the surroundings with LiDAR. Capture terrain undulations and obstacles that could cast shadows on panels (trees, buildings, utility poles, etc.) with the camera to collect point cloud data. Because the app displays the point cloud in real time, you can confirm coverage and avoid omissions as you proceed.

• Handle large-area measurements: For wide sites that cannot be scanned in a single pass, perform multiple scans by area. Since RTK gives all point clouds a common coordinate reference, integrating multiple scan results into a single model later is straightforward. Divide the survey area as needed to safely and reliably collect data for the entire site.

• Save and verify data: After surveying the necessary area, stop measurement and save the data in the app. Acquired point cloud data is stored on the smartphone and can be uploaded to the cloud and shared with a PC. Using LRTK’s cloud service, you can instantly send point clouds from the field to office PCs and easily share them within the team. Adding coordinate and orientation metadata to photos via the app’s photogrammetry functions helps when reviewing site conditions later. Organizing photos and notes taken on site together with the point cloud aids subsequent design work. Finally, the ability to inspect the point cloud on the spot to confirm there are no gaps is another advantage of smartphone surveying.

Importing acquired data into PVsyst

Next, import the acquired site data into PVsyst. LRTK provides raw data such as large numbers of 3D points (point clouds) and photos, but these must be converted into 3D models to reflect them in PVsyst’s 3D scene. For example, generate a mesh (polygon) representing the ground surface from the point cloud and export it in Collada (.dae) or 3DS format. For obstructions like trees and buildings, measure heights and outlines on the point cloud and replace them with simplified models such as cylinders or boxes. Once these model files are prepared, in PVsyst open the 3D scene (near shading) editor and execute "File -> Import -> Import 3D Scene" to load your 3D data. Note that it’s important to simplify models appropriately to reduce data volume; overly large 3D models can be difficult to handle in PVsyst, so adjust by reducing polygon counts while retaining required shape information.

In some cases, you can also construct the environment model manually in PVsyst while referencing the acquired data—for example, placing cylindrical objects of equivalent height in the PVsyst scene based on tree heights identified in the point cloud. With detailed data from LRTK, such modeling tasks become smoother. PVsyst v8 also offers functionality to automatically retrieve terrain data from satellite imagery, but its resolution is coarse and may not capture local terrain and structures. Modeling from your own high-precision data further enhances simulation reliability.

If the data imports correctly, a 3D scene reproducing the site’s terrain variations and surrounding obstructions will be built in PVsyst. You can then place solar panel layouts on this scene to perform shadow analyses that reflect the actual terrain and environment. PVsyst can calculate panel irradiation reduction (shadow losses) by time and solar altitude and the impact on annual energy yield in detail. Reflecting high-precision on-site data enables accurate reproduction of shadowing conditions for specific seasons and times, allowing problem areas to be identified during the design phase.

Dramatic improvements in design accuracy and work efficiency

This workflow significantly improves the accuracy and efficiency of solar PV plant design. Faithfully modeling the actual site terrain and shading increases the reliability of PVsyst’s energy simulations and greatly reduces uncertainty during planning. Improved simulation accuracy strengthens explanatory materials for financial institutions and stakeholders, enhancing overall project credibility.

For example, incorporating winter tree shading that was previously overlooked or planning layouts that follow actual terrain slopes can minimize gaps between predicted and actual performance. Countermeasures such as tree removal or adjusting racking heights can be evaluated in advance to minimize losses due to shading. Moreover, designing from detailed 3D data reduces the risk of rework after construction, such as finding the slope steeper than expected or unexpected shading locations.

Cases where LRTK-enabled detailed 3D designs were used have reported elimination of construction rework and actual energy yields exceeding expectations.

On the efficiency side, rapid smartphone surveying and immediate data linkage greatly shorten the design cycle. Where it previously took over a week to receive drawings or point cloud data from surveying companies and model them, LRTK allows acquisition of on-site data the same day and immediate analysis in PVsyst. With instant access to data, comparing multiple layout options via simulation becomes easy, enabling selection of more optimal plans in a short time. Allowing designers to collect and use their own site data reduces outsourcing costs and communication losses. Additionally, the high-precision data obtained once can be reused for design changes or future expansion planning, contributing to long-term efficiency gains.

Conclusion: Take design to the next level with smartphone-only simple surveying

Accurate simulation and an efficient design process are indispensable to the success of solar PV projects. The new surveying and design approach using iPhone × LRTK elevates the solar PV planning process to the next level. By easily obtaining high-precision on-site data and reflecting it in PVsyst analyses, you can simultaneously improve energy yield forecasts and streamline design work. The previously divided field and design processes become seamlessly connected, enabling designers to devise optimal plans that accurately reflect site realities.

The significance of LRTK enabling smartphone-only surveying is substantial. Even without large equipment or specialized knowledge, anyone can now perform centimeter-precision 3D surveys easily. Adopting such technological innovation makes solar PV design faster and more reliable than ever. As digital transformation of field operations accelerates in the renewable energy sector, the iPhone × LRTK approach can be seen as a forerunner. If you face challenges in improving accuracy or efficiency in your solar PV design work, consider introducing simple surveying with a smartphone and LRTK. Smartphone surveying broadens the possibilities of solar PV design, and the convenience of completing surveying through to analysis with a single device will support designers’ creativity and the creation of new value.