How to Use the Japanese Translation of PVsyst: Improve Design Efficiency with High-Precision Positioning Data

PVsyst is the world-standard software widely used for designing photovoltaic (PV) systems and simulating energy production. By inputting meteorological data and panel layouts, it can calculate generation, losses, and performance ratio (PR) with high accuracy. It also accounts for shading from surrounding buildings and trees, enabling simulations that faithfully reflect local site conditions.

However, the English interface can be a barrier for Japanese users. No matter how advanced the simulation, insufficient site input data prevents achieving true performance. This article provides a concrete guide to setting PVsyst’s Japanese-language interface and using high-precision positioning data such as LRTK to streamline design work.

What is PVsyst

PVsyst is PV simulation software developed in Switzerland. It is used by PV engineers worldwide to calculate annual energy yields, various losses, and performance ratios (PR) based on meteorological data and the configuration and layout of panels and inverters. It also supports importing various meteorological datasets from around the world (in Japan, for example, NEDO’s solar radiation data), allowing simulations under solar conditions appropriate for the design site. Because it can consider shading effects from surrounding terrain, structures, and trees, PVsyst enables highly accurate generation forecasts that closely reflect site conditions. Simulation results can be output as detailed reports that automatically summarize monthly and annual predicted generation, breakdowns of losses, and performance metrics (such as PR). These outputs are useful for financial planning of power plants and optimizing equipment configurations. From large utility-scale plants to rooftop residential systems, PVsyst is an indispensable tool for generation forecasting and layout optimization during design.

How to use PVsyst in Japanese and tips

PVsyst allows switching the interface display language from English to other languages, including Japanese. For those uncomfortable with English, switching to Japanese makes menus and settings more intuitive. The steps to switch to Japanese and how to make the most of it are as follows:

• Change the language setting to Japanese: After launching PVsyst, select “Language” from the main menu and switch to “Japanese.” Depending on the version, the software may detect your PC’s language settings and automatically display Japanese on first launch.

• Toggle between Japanese and English displays: Some translations can be too long for the screen or make technical terms harder to understand. In such cases, press the `F9` key to temporarily switch that screen back to English to check the original wording (press `F9` again to revert to Japanese). Using this feature to compare the Japanese translation with the original English helps you understand operations more reliably.

• Understand technical terms: PVsyst’s manuals and help are primarily in English. If Japanese UI labels are unclear, it’s helpful to know the English terms. Use the `F9` key on the translated UI to confirm the English term, and then search official documentation or case studies using that keyword to resolve issues.

Using the Japanese interface makes PVsyst’s settings and report contents easier to understand for users not fluent in English. Especially for first-time users, start with the Japanese display to grasp the overall workflow, and refer to English as needed as you become more familiar with the tool to work efficiently.

The importance of site data for design accuracy

While PVsyst enables detailed simulation, its accuracy heavily depends on the precision of input data. In layout design and generation forecasting for PV plants, how faithfully you model site terrain and surrounding obstructions determines success or failure. In addition to meteorological conditions and panel layout, PVsyst can account for site elevation, terrain slopes, and shading from nearby structures and trees. For example, if the site is surrounded by hills or high ground, you can set this as a horizon profile by defining the horizon elevation angle for each azimuth, and nearby trees or utility poles can be placed as 3D objects under the near object shading settings so their shadow effects are included in calculations. The more precise the site input data, the more reliable the simulation results, leading to an optimized design with less waste.

However, obtaining such detailed site data is not easy. Traditionally, field surveys and surveying take time and effort and require specialized skills. Representative methods used to obtain shading and terrain information include:

• Manual measurement of shading angles: Using a compass and inclinometer to measure the shielding angle of the horizon relative to solar elevation for key directions.

• All-sky camera analysis: Using a fisheye-lensed camera to capture 360° of the sky and analyzing images to determine the shading range and shadowing time from surrounding buildings and trees.

• Detailed topographic surveying: Surveyors conduct leveling and GPS surveys on site to obtain cross sections and contour data including elevation differences. Recently, drones are also used to create 3D terrain models (point clouds or DSM) from aerial photos.

• Estimation from map data: Referencing existing geographic data such as maps and aerial photos from the Geospatial Information Authority of Japan, or satellite imagery, to estimate site elevation and surrounding conditions.

Each method has challenges. While manual measurements and all-sky cameras require relatively accessible equipment, they have limits in coverage and precision when multiple points must be measured by hand. Professional topographic surveys and drone photogrammetry yield high-precision results but incur significant time and cost and require specialized knowledge and machinery. Estimations from maps and satellite images avoid field visits but face limitations in resolution and data age—for example, a building that wasn’t present in aerial photos from a few years ago or trees that have since grown can change shading conditions.

As a result, no matter how precise the calculations in PVsyst are, if input data diverges from actual site conditions, simulation results will not match reality. A carefully planned plant can suffer from unexpected shading effects that reduce expected generation.

Using high-precision positioning data in PVsyst

So how can high-precision site data be concretely applied to improve design? Here we introduce key ways to import data obtained from high-precision GPS positioning into PVsyst to enhance design accuracy.

• Accurate horizon profile settings: With high-precision positioning from LRTK, you can acquire terrain information around the site (heights of distant hills and buildings) and accurately determine horizon elevation angles for each azimuth. Reflecting that data in PVsyst’s horizon definition tool allows for precise consideration of shading relative to sunrise/sunset times and solar elevation throughout the year. This leads to realistic evaluation of generation losses during early morning and late evening.

• Shading simulation of surrounding objects: Measured coordinates and height data for nearby trees, utility poles, and structures can be used in PVsyst’s 3D shading features. By placing objects at the correct scale in the 3D scene using measured dimensions, you can simulate shadows cast on panels by season and time of day with high precision. For example, if you measure multiple trees, you can quantitatively evaluate how much shade each tree casts on panels over the year and adjust the layout (such as avoiding shadows or optimizing spacing) accordingly.

• Introducing detailed terrain models: On large or undulating sites, the terrain itself affects generation. By collecting many high-precision positioning points with LRTK, you can create a 3D terrain model from the point cloud. Importing such terrain models into PVsyst (or adjusting array layouts in PVsyst to match terrain cross sections) and setting panel tilt angles and heights to reflect actual conditions enables reproduction of generation impacts due to slopes and shading caused by valleys and hills. Advanced analyses—such as placing panel layouts on 3D models generated from LRTK point clouds and animating shadows on each panel in PVsyst—are also possible. These results are useful for identifying potential problem areas during design (for example, a specific row experiencing extended morning/evening shading) and informing design modifications.

By leveraging high-precision positioning data from LRTK, the reproducibility of PVsyst simulations dramatically improves. Using models that correctly reflect site realities makes post-construction performance predictions more reliable, increasing confidence in investment decisions. When making fine adjustments during design (layout tweaks or equipment selection), basing decisions on measured data reduces rework and ultimately leads to greater design efficiency.

Simple surveying with LRTK and benefits for field adoption

A recently notable method for obtaining high-precision site data is smartphone-based simple surveying. (Japan’s i-Construction initiative by the Ministry of Land, Infrastructure, Transport and Tourism also emphasizes ICT and labor-saving in surveying.) A representative solution is known as “LRTK,” which brings centimeter-level surveying—previously only possible by specialists—within easy reach.

What is LRTK? In short, it is an ultra-compact high-precision GPS receiver (RTK-GNSS device) that can be attached to a smartphone. Using RTK (Real-Time Kinematic) technology to correct positioning errors, it reduces typical GPS errors of several meters to centimeter-level accuracy. Connect an LRTK device to a smartphone, launch the dedicated app, and press a button at the point you want to measure—the device immediately records the latitude, longitude, and elevation with high precision. Measurement results are automatically converted to Japan’s plane coordinate system and elevation, allowing coordinates obtained on-site to be used directly in design drawings or CAD coordinate systems.

The on-site advantages of LRTK surveying include:

• Easy one-person surveying: LRTK is designed for intuitive smartphone operation and can be used by non-specialist surveyors. The compact device weighs only a few hundred grams and includes antenna and battery, eliminating bulky tripods and long cables. You can walk the site holding the device in one hand and control the smartphone with the other to record measurement points quickly. Tasks that used to require two people can often be done solo with LRTK, covering large areas in a short time.

• Immediate sharing and utilization of collected data: Measured position data can be uploaded to the cloud in real time or plotted on the smartphone map for on-site confirmation. Multiple measured points can have distances and elevation differences calculated on the spot, removing the need for handwritten notes. Because data collected on-site can be reflected in PVsyst designs immediately, lead times from field survey to simulation are significantly shortened.

• Positioning even where communications are unavailable: LRTK supports augmentation signals derived from Japan’s Quasi-Zenith Satellite System (QZSS), allowing centimeter-level positioning to continue even in mountainous areas or remote islands without cellular coverage. Many PV project candidate sites are in suburban or mountainous areas, so the ability to survey without relying on communication infrastructure is reassuring. No additional base stations or communication equipment are required, simplifying the equipment setup and reducing potential troubles.

If multiple LRTK devices are available, several team members can survey simultaneously. This enables dividing a large site among people to cover it quickly, turning multi-day surveys into single-day operations in some cases. Combining LRTK with the LiDAR scanner on the latest iPhones allows rapid acquisition of 3D point clouds of site terrain and structures. Because these point clouds are tagged with high-precision position coordinates from the start, they can be used directly to create 3D terrain models for detailed PVsyst simulations.

Introducing smart simplified surveying with LRTK greatly improves the efficiency of PV system design. By collecting necessary site data quickly in-house, you can proceed with planning based on accurate information from the early design stages. Tasks that previously required outsourcing to surveying specialists can be internalized, offering schedule and cost benefits. In real projects, using LRTK data has been shown to reduce design rework and improve the accuracy of generation estimates. For example, accurately measuring a ridge line with LRTK and revising a layout to account for a previously overlooked mountain shadow improved the annual predicted generation. In another case, detecting a slight slope on a seemingly flat site with centimeter accuracy allowed optimization of racking heights, preventing unexpected post-construction generation losses.

If you want to improve PV plant design efficiency and field productivity, consider introducing LRTK-based simplified surveying. Smart surveying using the latest technologies enables reliable designs with limited personnel and contributes to overall project optimization. As surveying and design digitalization (DX) progresses, execution of PV projects will become increasingly efficient and reliable. For more information about LRTK, please see [here](https://www.lrtk.lefixea.com).