Achieving Precision Surveying for Solar Power Plants with a Smartphone: Improve Design Efficiency with LRTK and PVsyst

Accurate surveying to understand the on-site topography and surrounding environment is indispensable in designing solar power plants. However, conventional surveying has required specialized equipment and advanced skills, consuming significant time and cost. As a result, in early stages it has often been necessary to simplify terrain data or rely on general map information for design. Attracting attention in this context is a new surveying method using a smartphone and LRTK. LRTK is a high-precision positioning device that can be used with a smartphone, enabling centimeter-level (half-inch-level) surveying without relying on dedicated equipment. In this article, we explain in detail—from background and challenges to technology, usage methods, effects, and integration with AR and point cloud data—how precise surveying with a smartphone and LRTK can improve design efficiency and accuracy in designs using the world-standard solar simulation software PVsyst.

Background: The importance of on-site surveying in solar power plant design

With the recent acceleration of renewable energy deployment, many solar power plant projects are being advanced across various regions. Their success depends on accurately understanding the topography and surrounding environment of each candidate site and making appropriate design decisions. Accurately grasping local terrain and insolation conditions is crucial for determining plant layout and expected power generation. Slope angles and orientations, and the positions and heights of surrounding obstacles that can cast shadows (such as trees and buildings), greatly affect panel layout plans and shading loss calculations. Simulation software like PVsyst can produce more realistic generation forecasts when site-specific information like this is input. For example, recommended racking designs and row spacing differ between gently sloping and steep sites, and tall nearby structures can cause year-round shading losses. Designing without accurate survey data can lead to unexpected shading effects after completion or incompatibility with the land shape, necessitating design changes or reducing generation output. Therefore, obtaining precise surveying data from the early stages and reflecting it in the design is required.

Challenges: Problems with conventional surveying methods

Conventional surveying carries a strong image of “something to be entrusted to specialists,” and it is common to set up large-scale equipment and perform team-based work on site. High-cost specialized equipment such as transits, total stations, and GNSS positioning devices are used, and even placing reference points requires advanced adjustments by experienced personnel. Thus, even small-scale surveying work often must be outsourced to surveyors, creating high hurdles in terms of time and cost. Moreover, digitizing the obtained survey results and reflecting them in design takes effort, and real-time information sharing between the field and the office is not easy.

Because of these hurdles, initial designs for solar power plants sometimes omit detailed on-site surveying and rely on Geospatial Information Authority maps or simple site checks to determine layouts. In such cases, accurate slopes and the heights of adjacent objects cannot be grasped, posing a risk of discrepancies between simulated and actual generation. When detailed surveying is performed later in the project, it can result in reconsideration of panel placement or additional civil works (e.g., more land grading than anticipated), affecting project schedules and costs. In short, conventional methods present a dilemma of “knowing it’s necessary but not being easy to do,” which has been a major challenge for field engineers.

High-precision surveying enabled by Smartphone × LRTK

Small, smartphone-compatible surveying devices such as LRTK, which have appeared in recent years, are dramatically changing surveying conventions. They are attracting attention among site construction managers and engineers as “surveying instruments that fit in your pocket,” and there is a movement to have one per person to improve work efficiency. LRTK is an ultra-compact RTK-GNSS receiver attached to a smartphone, and a smartphone equipped with it instantly gains centimeter-level (half-inch-level) positioning capability. RTK (Real-Time Kinematic) is a technique for correcting satellite positioning errors; by using correction information from base stations or the Quasi-Zenith Satellite System’s centimeter-level augmentation service (CLAS), GPS positioning errors that are normally several meters (several ft) can be reduced to a few centimeters or less (a few in or less). LRTK supports multiple GNSS frequency bands and can continue high-precision positioning even in mountainous areas without internet by directly receiving CLAS signals. Dedicated smartphone apps allow users to check satellite reception and accuracy, making it possible for anyone to reliably achieve high-precision positioning.

The greatest advantage of surveying with smartphone + LRTK is its ease and responsiveness. Preparation is complete simply by attaching a pocket-sized device to a smartphone—no heavy tripods or complex setup are required. Tap a button on the smartphone screen at the point you want to measure, and the latitude, longitude, and elevation are recorded instantly. Even non-specialist personnel can gather sufficiently accurate data while moving around the site alone, making it far easier to perform the detailed early-stage surveying that was often postponed under conventional approaches.

Also noteworthy is the ability to leverage the smartphone’s high-performance sensors. Combining the smartphone’s camera and LiDAR (light detection and ranging) sensors (※LiDAR-compatible models) with LRTK’s high-precision position data allows on-site conditions to be captured directly as 3D point cloud data. By walking around the survey site and scanning the surroundings, a detailed 3D model composed of countless measurement points can be obtained in a short time. Because each point in the acquired point cloud has accurate coordinates, it is easy to later measure arbitrary distances, areas, and height differences or to calculate terrain variation and earthwork volumes. Point cloud data and survey coordinates can be shared to the cloud immediately from the field, allowing design staff in the office to confirm and use them in real time. In this way, LRTK technology, which transforms a smartphone into a “universal surveying instrument,” not only dramatically lowers the hurdle to surveying but also greatly expands the types of data obtained and how they can be used.

How to use in PVsyst design: Smartphone surveying procedures

High-precision survey data from a smartphone and LRTK can be directly applied to the solar power plant design workflow. Below is a typical procedure from on-site surveying to use in PVsyst.

• Acquiring site boundaries and basic information: Record the site’s boundary lines and shape using smartphone surveying. Measure positions at the four corners of the site and at characteristic points to determine the accurate area and shape of the land. This clarifies the areas where panels can be placed and provides an accurate extent for layout consideration in PVsyst.

• Collecting terrain (elevation) data: Obtain elevation data within the site. On large sites, set measurement points at regular intervals to measure heights; using the smartphone’s scanning functions to create a point cloud of the entire ground surface is also effective. From the resulting thousands to millions of 3D points, create a digital terrain model (DTM) to accurately model slopes and elevation differences. In PVsyst, these terrain data can be used to optimize panel tilt and layout and to evaluate insolation differences due to topography.

• Measuring surrounding obstacles and shadow factors: Measure the positions and heights of objects that may block sunlight around the site (for example, tall trees or buildings to the south). By capturing tree tops or building edges with the smartphone’s camera AR functions or point cloud scans, you can obtain 3D positions with height information for those objects. This enables construction of a full 360-degree horizon profile and proximity object layout model, which can be reflected in PVsyst’s “definition of horizon” and “nearby shadow” scenarios. Accurate input of shading factors is indispensable for evaluating generation losses, especially at dawn/dusk and in winter.

• Modeling survey data and input to PVsyst: Prepare the collected survey data for import into PVsyst. Terrain and obstacle models derived from point cloud data can be polygonized or simplified in CAD software as needed and imported into PVsyst’s 3D scene. Alternatively, extract important measurement points (for example, locations where slope changes) and reflect them in PVsyst as terrain cross-sections or height maps. The latest versions of PVsyst make 3D model import easier, allowing you to run generation simulations with the surveyed terrain layout as-is.

• Design and simulation: Use the detailed terrain and surrounding information obtained in PVsyst to carry out panel layout and system design. For example, you can arrange panel rows in terraces to match the terrain model or avoid specific areas to optimize layout for on-site conditions. Because surrounding trees and structures are reproduced in the 3D scene, PVsyst can simulate the movement of shadows across seasons and times of day to quantitatively assess annual shading losses. By obtaining precise simulation results (expected generation and loss breakdown) based on on-site survey data, the accuracy of investment decisions and construction plans is greatly improved.

• On-site verification and feedback: Once the simulation-based design policy is determined, perform a field verification using the smartphone and LRTK. Use the smartphone’s navigation or AR display to check on-site whether the positioned panel rows are practical and whether the assumed clearances and access paths can be secured. If necessary, add survey data on the spot and feed it back into the design. This iterative process quickly resolves discrepancies between desk plans and actual site conditions, improving the completeness of the design.

By following the above steps, you can fully utilize the precise data obtained by smartphone surveying in PVsyst design and simulation. Projects that incorporate on-site information from the early stages will have smaller gaps after completion, minimizing divergence between predicted and actual generation.

Utilizing AR technology and point cloud data: Next-generation design and construction

Combining detailed point cloud data obtained by smartphone surveying with the high-precision positional information from LRTK is taking the integration of design and site work to a new level. A prominent example is the use of AR (augmented reality) technology. Conventional AR has often suffered from alignment errors, making it difficult to maintain accuracy in large outdoor projects. However, as smartphones can now continuously determine centimeter-level (half-inch-level) positions, it has become possible to align real space and digital design models precisely. If 3D models of designed solar panel rows and equipment are displayed in AR over the site scenery, they can be confirmed as if the actual objects were installed there. Because the models do not drift or float and are always displayed in the correct position and orientation as users walk around, on-site checks and stakeholder briefings can be performed intuitively and accurately.

For example, projecting a designed layout onto the ground via AR allows you to visually check clearances from site boundaries and spacing between rows on the spot. You can also compare the simulated shadow lengths and directions at specific times with the site and consider tree removal extents accordingly. Using AR enables you to grasp elements that might be overlooked on paper or a screen at real scale, facilitating smoother decision-making during the design phase.

Meanwhile, acquired point cloud data can be considered a precise digital twin of the site. Using it in design software allows detailed design review of site topography and obstacles from the office. Visualizing point clouds overlaid with design models is effective for examining the necessary scope of earthworks, retaining wall heights, or optimizing routing for pipes and cables. During construction, comparing the predicted completion model with as-built point clouds makes it possible to assess work quality, and displaying the locations of underground utilities in AR can reduce excavation risks.

Thus, survey data from smartphone + LRTK can be used not only for PVsyst generation simulation but across the entire lifecycle—from design to construction and maintenance—when combined with AR and point cloud technologies. In renewable energy projects, the boundary between digital and real continues to blur, enabling more efficient and reliable project execution.

Conclusion: The future of solar design opened by smartphone-only surveying

Surveying methods using smartphones and LRTK are bringing innovation to the solar power plant design process. Easy access to detailed on-site terrain and environmental data from the early stages dramatically improves the accuracy of simulations using PVsyst, minimizing rework and the risk of generation loss. The fact that surveying work, once reliant on specialists, can now be completed with a single smartphone symbolizes the DX (digital transformation) taking place in the renewable energy sector.

Designs supported by high-precision survey data make post-completion performance more certain and lend credibility to investment evaluations and stakeholder explanations. Through AR visualization and cloud-based information sharing, all project stakeholders can share the same on-site image, enabling smooth communication from planning through construction and operation.

Thanks to devices like LRTK, “smartphone-only, simplified surveying” has become a reality. If you face challenges in improving the design efficiency or accuracy of solar power projects, consider trying smartphone surveying. The technology in the palm of your hand will surely bring new possibilities to your projects. The integration of smartphone surveying and PVsyst simulation is likely to become a new standard in future solar power plant design. A scene where surveying and design are done with a smartphone in hand may soon become commonplace.