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

In designing solar power plants, accurately understanding the site terrain and shading conditions is crucial. PVsyst is a representative software that can simulate the energy production and impacts of photovoltaic systems, and the accuracy of input data greatly affects the reliability of analysis results. In recent years, methods combining smartphones with advanced technologies have emerged that allow on-site surveying more easily and with higher accuracy than traditional approaches. This article explains how incorporating high-accuracy terrain, shadow, and structure data obtained by surveying with an iPhone and LRTK into PVsyst analysis can dramatically improve design accuracy and work efficiency. From the challenges of conventional surveying and modeling to the advantages of LRTK, field usage, data import workflow, and reflecting results in design, each step is explained in order. At the end of the article, we also introduce a simple phone-only surveying method using LRTK.

Challenges in Conventional Surveying and Modeling

In solar power plant design, surveying and 3D modeling are first performed to understand the site terrain and surrounding obstructions (structures, trees, etc.). However, conventional methods had many challenges. Terrain surveying required expensive, bulky equipment such as total stations or GNSS receivers, and skilled surveyors needed to obtain numerous measurement points on site. Drone photogrammetry has also become widespread, but flight time is limited by battery constraints, and data processing takes time and effort—such as measuring ground control points (GCPs) in advance for georeferencing. Ground-based laser scanners are another option, but those instruments are also costly and require specialized operational skills. Furthermore, in heavily forested sites aerial imaging can fail to capture the ground surface, meaning terrain under trees cannot be acquired.

Because these methods require cost and days to obtain detailed 3D point cloud data, project teams sometimes must proceed in the early design stages without sufficient information. If subtle terrain undulations or small obstructions around the site—such as utility poles or trees—are overlooked, there is a risk of discrepancies between PVsyst simulation predictions and actual performance. In fact, solar panels can suffer reduced output for the entire string even if only a part is shaded, so accurately estimating shading effects is indispensable. For example, if there are trees that cast long shadows in winter but they are not reflected in the model, the energy yield may be overestimated. Conversely, overdesigning to mitigate perceived shading risk can reduce installed capacity or increase array spacing unnecessarily, harming the plant’s profitability. In short, the uncertainty of conventional surveying and modeling constrained design accuracy and efficiency.

High-Accuracy On-Site Surveying with iPhone × LRTK

A cutting-edge solution to these challenges is smartphone-based mobile scanning. Specifically, this method combines an iPhone’s built-in LiDAR (light detection and ranging) sensor with high-precision GNSS RTK (Real Time Kinematic) positioning to 3D-scan the site, enabling detailed point cloud acquisition without relying on specialized equipment. iPhone 12 Pro and later models include LiDAR that can measure distance up to approximately 5 m (16.4 ft), allowing surrounding shapes to be recorded as collections of many points (point clouds). However, LiDAR on the phone alone does not include geographic coordinates (latitude, longitude, elevation) in the acquired data, so point clouds needed to be georeferenced afterward for surveying purposes. By combining RTK centimeter-level positioning (centimeter-level positioning (half-inch accuracy)) with phone scanning, accurate position information can be attached to phone-scanned point clouds immediately, and multiple scans across large sites can be integrated into precise 3D models. Standard GNSS positioning typically has errors on the order of several meters (several ft), but using RTK can improve accuracy to within a few centimeters (within a few in).

LRTK is a representative solution that realizes this phone × RTK surveying. It consists of a compact RTK-GNSS receiver (with an integrated antenna) that attaches to an iPhone and a dedicated app, enabling centimeter-level positioning and 3D scanning with the ease of one-handed operation. The dedicated app’s UI is intuitive and easy to understand, so it can be used on site immediately without specialized training. Because it supports RTK services such as QZSS “Michibiki” CLAS (centimeter-level augmentation service), stable high-precision positioning is possible even in mountainous areas or sites outside mobile reception where conventional methods were difficult. Acquired data can be saved and shared to the cloud on the spot, and point clouds can be checked on the phone while working. The iPhone thus becomes an all-purpose surveying tool comparable to traditional survey instruments, bringing innovation to time- and cost-intensive conventional methods. This phone × RTK 3D measurement approach is gaining attention in the construction and surveying industries and may become mainstream as a new surveying approach that does not rely on specialized equipment.

Using LRTK for on-site investigation of solar power plants offers the following benefits:

• High-precision 3D data: RTK enables acquisition of 3D data of terrain and structures with accuracy within a few centimeters (within a few in), ensuring complete capture of on-site information needed for design.

• Streamlined survey and design: Because surveying can be completed with only a smartphone and a small device, there is no need to arrange specialized contractors or heavy equipment, allowing site investigation and reflection in the design to proceed in a short time.

• Accessibility in difficult areas: Even in urban areas, mountainous regions, or under trees where drones cannot easily fly, walking while scanning enables acquisition of comprehensive point cloud data.

• Intuitive and safe operation: Real-time point cloud visualization on the phone prevents omissions, and there is no need to carry heavy equipment into hazardous locations.

• Immediate use of digital data: Because coordinates are attached to acquired data, it can be imported directly into design software without post-processing for georeferencing. Distances and heights can be measured immediately from on-site point clouds, aiding layout considerations.

Field Procedure for iPhone × LRTK Surveying

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

• Equipment and app preparation: Before surveying, attach the LRTK device to the iPhone and launch the dedicated app. Configure correction information over the network (Ntrip, etc.) so that RTK centimeter-level positioning (centimeter-level positioning (half-inch accuracy)) is available. (In areas without mobile coverage, the device will receive corrections via supported satellite augmentation services.)

• Start LiDAR scanning: Start measurement using the app’s 3D scan function, hold the iPhone and walk around the site while scanning the surroundings with LiDAR. Capture terrain undulations and obstacles that may cast shadows on panels (trees, buildings, utility poles, etc.) with the camera and collect point cloud data. Because the point cloud is displayed in real time on the app screen, you can proceed while confirming there are no omissions.

• Handling large-area measurements: For large sites, you may not be able to scan the entire area in one pass. In that case, perform multiple scans by area. Because RTK gives a common coordinate reference to all point cloud data, integrating multiple scans into a single model later is easy. Dividing the measurement points as needed enables safe and reliable acquisition of data for the entire area.

• Save and verify data: When the necessary surveying is complete, stop measurement in the app and save the data. Acquired point clouds are stored on the phone and can be uploaded to the cloud for sharing with a PC. Using LRTK’s cloud service, you can send acquired point clouds from the field directly to office PCs and easily share them within the team. Using the app’s photolocation function to attach coordinate and orientation information to captured images will also help when reviewing site conditions later. Organizing photos and notes taken on site together is useful for subsequent design work. Finally, the ability to survey the point cloud on the spot to check for missing data is another advantage of phone-based surveying.

Importing Acquired Data into PVsyst

Next, import the acquired site data into PVsyst. LRTK yields raw data such as many 3D points (point clouds) and photos, but these must be processed into 3D models before being reflected in PVsyst’s 3D scene. For example, generate a mesh (polygons) representing the site surface from the point cloud and export it in Collada (.dae) or 3DS format. For obstructions like trees and buildings, measure their heights and outlines on the point cloud and replace them with simplified models such as cylinders or boxes. Once these model data are prepared, in PVsyst’s 3D scene (near shading) editor run “File -> Import -> Import 3D Scene” and load the created 3D data. Note that it is important to suitably simplify details in models generated from point clouds to reduce data size. Excessively large 3D models become difficult to handle in PVsyst, so adjust by reducing polygon counts while retaining necessary shape information.

In some cases you can also build the environment model manually in PVsyst while referencing the acquired data. For example, based on tree heights identified from the point cloud, place cylindrical objects of equivalent height in the PVsyst scene. However, obtaining detailed data with LRTK makes such modeling work smoother. PVsyst v8 also provides a function to automatically obtain terrain data from satellite imagery, but the resolution is coarse and cannot reflect local terrain and structures. Modeling from your own high-precision data further increases simulation reliability.

When data are successfully imported, a 3D scene that reproduces the site terrain undulations and surrounding obstructions is constructed in PVsyst. From there, placing the solar panel layout on this scene allows shadow analysis that reflects the actual terrain and environment. PVsyst can calculate panel irradiance loss (shadow loss) by time and solar elevation and detail the impact on annual production. With high-precision on-site data reflected, shadow occurrences at specific seasons and times can be accurately reproduced, allowing problem areas to be identified during the design phase.

Dramatic Improvements in Design Accuracy and Work Efficiency

The workflow above dramatically improves both design accuracy and work efficiency for solar power plants. Faithfully reflecting actual site terrain and shading in the model increases the reliability of PVsyst’s generation simulation results and greatly reduces uncertainty during planning. Improved simulation accuracy enhances the persuasiveness of explanatory materials to financial institutions and stakeholders, raising the overall credibility of the project.

For example, incorporating tree shading effects that are often overlooked in winter or planning layouts that reasonably follow terrain slope can minimize the gap between forecast and actual performance. Countermeasures such as tree removal or adjusting mount heights that mitigate shading can be considered in advance, enabling design decisions that minimize generation losses due to shading. Moreover, designs based on detailed 3D data reduce the risk of rework after construction, such as “the slope was steeper than expected and installation is difficult” or “unexpected shading occurs in some locations.”

There are reports that projects using LRTK for detailed 3D design eliminated rework during construction and ultimately achieved energy yields above expectations.

From an efficiency standpoint, rapid surveying with a smartphone and seamless data linkage significantly shortens the design cycle. Traditionally, it took more than a week to receive drawings or point cloud data from surveying firms and model them, but with LRTK you can acquire data on the same day as the site survey and begin PVsyst analysis immediately. With data available instantly, it becomes easy to compare multiple layout scenarios via simulation and derive more optimal plans in a short time. When designers themselves can collect and use on-site data, it reduces outsourcing costs and prevents communication loss. Additionally, once acquired, high-precision data can be reused for design changes or future expansion studies, contributing to long-term efficiency gains.

Conclusion: Take Design to the Next Stage with Phone-Only Simple Surveying

Accurate simulation and an efficient design process are essential for successful solar power projects. The new surveying and design method using iPhone × LRTK elevates the solar power plant planning process to the next stage. By easily acquiring high-precision on-site data and reflecting it in PVsyst analysis, you can simultaneously achieve improved accuracy in energy forecasts and greater design efficiency. The previously fragmented 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 considerable. Without large-scale equipment or specialized knowledge, anyone can easily perform centimeter-level 3D surveying (centimeter-level positioning (half-inch accuracy)). By adopting such technological innovations, solar power plant design becomes faster and more reliable than ever. As field DX (digital transformation) accelerates in the renewable energy sector, the phone + LRTK method can be viewed as a pioneer. If you are facing challenges in improving accuracy or efficiency in solar design work, consider introducing simple surveying with a smartphone and LRTK. Phone-based surveying expands the possibilities of solar PV design. The convenience of completing surveying through analysis with a single smartphone will support designers’ creativity and lead to the creation of new value.