AR Panel Placement Verification Spotlighted at Solar Expo: Dramatic Reduction in Installation Errors and Improved Accuracy

At this year's solar power-related exhibition (hereafter "Solar Expo"), the technology of verifying solar panel placement on-site using AR (augmented reality) attracted considerable attention. While the solar power market is expanding, construction sites face many challenges such as panel placement errors, discrepancies with design drawings, labor shortages, and increased costs from rework. As a practical solution to these problems troubling industry stakeholders, AR technology that projects and verifies installation positions on-site was proposed. This article explains in detail the challenges at solar power installation sites and AR technology as a solution, specific use cases and benefits, and how DX (digital transformation) can be applied across the workflow from design to construction and inspection. Finally, it touches on simple surveying using the latest technology "LRTK," which supports high AR placement accuracy, and considers the outlook this brings to the solar power industry.

Current State of the Solar Power Market and On-site Challenges

Buoyed by momentum for renewable energy promotion, installations of solar power systems are accelerating across Japan. As installation projects increase from residential roofs to mega-solar sites, the following issues have been pointed out at sites:

• Panel placement errors: Slight deviations in panel mounting positions or angles can cause overall system distortion or interference with adjacent structures. For example, a difference of a few centimeters in a racking support column position can cause mounting bracket hole positions not to line up or wiring to be out of reach. As a result, additional on-site work or adjustments become necessary, leading to quality degradation and reduced power generation efficiency (e.g., not receiving the expected sunlight, inability to secure maintenance walkways).

• Design errors and inconsistencies with drawings: If initial site surveys or designs are inadequate, discrepancies such as “the actual slope was steeper than designed” or “the obstacle’s location differed from the drawing” may be discovered at the construction stage. Oversights during the design phase can lead to situations where panels do not fit in the planned locations or become shaded once installed. In such cases, design rework or sudden plan changes on site occur, causing overall project delays and cost increases.

• Labor shortages: The rapid spread of solar power has outpaced the availability of experienced construction technicians and surveyors. For mega-solar construction across vast sites, many surveying and construction staff are ideally needed, but chronic labor shortages force a small crew to handle countless panel installations. Aging veteran staff and a lack of younger workers compound the issue, increasing individual workloads and the risk of human error.

• Rising rework costs: Delays due to the above mistakes and personnel shortages often lead to rework (redo). Removing and repositioning installed panels or piles, reassembling racking, and performing additional wiring or reinforcement work result in significant time loss and financial burden. If schedule delays push back inspections or handovers, trust with clients may be affected. Environmental impacts from increased material waste and heavy equipment operation also cannot be ignored, so it is essential to complete work accurately and efficiently in one go.

In response to these challenges, the industry expects construction DX through use of digital technologies. Among these, on-site AR verification of panel placements has drawn attention as a trump card that supports construction sites both in accuracy control and efficiency improvement.

Overview of AR Technology and Its Application to Solar Panel Installation

AR (augmented reality) is a technology that overlays digital information onto the real-world view. Through a smartphone or tablet camera, virtual objects or lines appear on the screen as if they exist in front of you. Applying this technology to solar panel installation makes it possible to project panel layouts and reference lines from design drawings onto the actual site.

For example, even when nothing has yet been installed on a roof or land, an AR app can display the panel layout according to the design, visually indicating installation positions and angles. Because it looks as if virtual panels are floating on-site, installers do not need to interpret drawings in their heads and can work while confirming the completed image on the spot. Compared with the traditional method of measuring dimensions with paper drawings and a tape measure and marking them manually, following on-screen guides is intuitive. The clarity of direct spatial guidance enables workers who are not veterans to position equipment at accurate locations and orientations, significantly reducing human error.

Moreover, recent AR construction support systems combined with high-precision positioning technologies can achieve AR displays accurate to within a few centimeters. Simple AR functions previously suffered from drift where the displayed position would slowly shift as the device moved. However, by continuously correcting the device’s position and orientation using GNSS (satellite positioning) and inertial sensors, virtual objects remain precisely fixed at their intended real-world positions even while walking around. This is revolutionary for using AR in construction, and demos at the expo impressed attendees with comments like “the display really doesn’t drift!” With AR accuracy improvements enabling seamless overlay of real space and digital designs, on-site use for solar panel installations has become a practical reality.

AR Use Cases: From Residential Roofs to Mega-Solar Sites

AR-based panel placement verification is being applied across a variety of site sizes and types. Below are representative use cases by scene.

• Detached house roofs: Even for houses with complex roof shapes, AR can project and confirm panel layouts in advance. It is possible to check on-site whether panels will fit while avoiding obstacles such as chimneys and vents, and whether slopes and orientations match the design, allowing layout adjustments on the spot if necessary. Also, showing the completed image to homeowners on-site helps prevent misunderstandings like “it looks different after installation,” and aids in gaining prior agreement.

• Ground-mounted solar farms (open field): AR demonstrates its value on vast sites with many panels, such as mega-solar constructions. By showing the designed rows of panels and foundation pile positions on the ground with AR while workers walk and mark, a single person can set many positions in a short time. Tasks that previously required a survey team to measure each pile location can now be completed by marking according to AR guides, greatly reducing manpower and time. AR is also effective at preventing pile-driving mistakes across thousands of piles while maintaining overall alignment.

• Parking lot carports: For carports with panels installed over parking lots, designs need to consider vehicle placement and shade movement. With AR, you can virtually project panel roofs and pillar positions over parking spaces to intuitively examine impacts on vehicle movement and sun exposure. You can confirm on-site whether pillar positions will obstruct vehicles and whether roof coverage is sufficient, preventing post-installation touch-ups due to image mismatches. It also helps confirm harmony with the surrounding environment, useful for explaining aesthetic considerations.

• Large factory and warehouse rooftops: On wide flat rooftops densely covered with panels, AR can display guideline grids according to the planned layout. Workers simply walk the roof and mark according to grid lines and panel frames shown on the screen to achieve perfectly aligned panel placement even on expansive roofs. Since equipment like air conditioning units and exhaust ducts can also be displayed in AR, it’s easy to verify at a glance whether placement avoids those items. Traditionally, laying out positions on a large rooftop required much effort with tape measures and chalk, but AR enables rapid and accurate layout checks and marking.

As shown above, AR panel placement verification demonstrates effectiveness as a pre-construction confirmation and guidance tool across sites from residential to industrial. The strength of being able to “reproduce the design drawing directly on-site” is being utilized in diverse applications.

Benefits from Improved Pre-installation Verification Accuracy

When AR dramatically improves pre-installation verification accuracy, the benefits to the site are significant. The main advantages are summarized as follows.

• Prevention of construction errors: Following AR’s clear visual guides prevents mistakes caused by mismeasurement or misreading positions. As digital assistance supplements parts previously reliant on human reading and manual measurement, human errors such as “drilling holes in the wrong place by mistake” or “missing a marking” can be dramatically reduced. Consequently, the probability of completing the work correctly on the first attempt increases, greatly reducing rework. From the perspectives of quality trouble prevention and safety assurance, this is a step toward zero installation errors.

• Consensus building with customers and stakeholders: Sharing the completed image in advance via AR has a major impact on communication with owners, local residents, and clients. When installing panels on a residential roof, showing the homeowner “this is how it will be installed” on-site makes the eventual appearance concrete and reassuring. For large projects, using AR at community briefings to demonstrate visual impacts helps gain understanding. Because everyone can view the same final diagram, consensus formation becomes smoother, avoiding disputes such as “we weren’t told” or “it looks different from expectations.”

• Increased construction speed and efficiency: Using AR reduces the time required for layout marking and inspection, accelerating overall construction. Large sites that previously needed days for surveying and setting out can be completed quickly with AR navigation, allowing installation work to start sooner. By reducing rework through error prevention, project schedules are shortened. Additionally, because on-site communication can proceed while viewing AR imagery, time spent pointing and confirming drawings is reduced, improving team coordination. Efficiency gains also help mitigate labor shortages, enabling small crews to work at a pace beyond previous capabilities.

In addition, achieving design-level accuracy in construction contributes to maximizing power generation performance and equipment lifespan. Maintaining optimal panel orientation and spacing yields the simulated power output, and arranging for unobstructed maintenance access helps prevent future problems. AR’s pre-verification raises not only immediate site efficiency but also the long-term outcomes of projects.

Integrating DX into the Design–Construction–Inspection Workflow

AR panel placement verification is not just an on-site gadget but enables a new workflow that consistently uses digital data from design through construction and post-completion inspection. It connects processes that were traditionally fragmented and advances construction DX. Let’s look concretely at this flow.

• Design stage – In the initial planning and design phase, optimal layouts are considered using detailed site data and simulations. If digital design data created in BIM software or PV simulation tools can be projected on-site via AR, you can pre-check discrepancies between desktop plans and actual site conditions. For example, designers can walk candidate sites with a tablet displaying virtual panels in AR to identify issues that drawings alone wouldn’t reveal, such as “this tree might cast shade in the afternoon.” On-site feedback can be immediately reflected in the design, enabling creation of higher-fidelity plans. These digitally optimized layouts then transfer smoothly to the construction phase.

• Construction stage – During construction, finalized design data is loaded into AR-compatible apps for site use. Field staff work with a smartphone or tablet and follow digital design overlays on the actual site while carrying out tasks. The workflow begins with calibration at reference points to align the device, then staff install components following on-screen lines and markers. There are systems that provide navigation like “north by XX cm, east by XX cm” to guide staff to pile-driving points, eliminating the need to repeatedly check paper drawings and measure out dimensions. By checking positional correctness on AR at key points, deviations during construction can be corrected immediately. Digital navigation enables high-precision construction without relying on craftsmen’s intuition or experience.

• Inspection and maintenance stage – AR is also effective for post-completion inspections and regular maintenance. Inspectors hold up a device on-site to overlay the design (or BIM model) onto the finished work for comparison. This allows visual detection of deviations of a few centimeters that are hard to spot with the naked eye, enabling more efficient and accurate inspections than before. For example, if “only this row appears slightly off,” comparing the as-built to the ideal position in AR makes it immediately clear. When inconsistencies are found, corrective actions can be taken and photos taken with AR overlays saved as digital construction records. These records are useful for future maintenance planning and root cause analysis if problems occur. Presenting AR visuals during official inspections can also streamline approval. By incorporating AR into the workflow, design, construction, and inspection data are consistently utilized, realizing an ideal DX.

Ease of Use via Smartphones and Tablets

One major feature of AR construction support is that it can be used with a handheld smartphone or tablet. No expensive dedicated equipment or special headsets are required; on-site staff can simply install an app on their usual mobile device to start AR-based placement verification. Intuitive user interfaces are designed so that anyone can operate them, allowing workers without special training to master the system after a short explanation.

For example, at a demo during the expo, an experienced construction manager could identify pile positions simply by walking along AR lines shown on a smartphone screen, saying it felt like using a car navigation system to arrive at the pile-driving spot. Younger technicians likewise commented that it felt like a game to perform on-site positioning, indicating the interface is readily accepted regardless of age or experience.

The smartphone/tablet approach also offers mobility and low cost. Previously, transporting stationary surveying equipment and large drawings made mobility on roofs and uneven sites burdensome. An AR system that only requires a smartphone and a small accessory can be used single-handedly on a roof to perform on-the-spot checks. The compact equipment runs on built-in batteries, enabling quick deployment anywhere. From a cost perspective, using existing devices is cheaper than purchasing dedicated hardware and reduces preparatory burdens. No need for per-site lends or setup simplifies introduction, so the system can be flexibly deployed from small sites to simultaneous multi-site operations.

In short, AR construction support on smartphones and tablets is attractive because it is “usable by anyone, anywhere, immediately.” This lowers psychological barriers to adopting new technology and is an important factor promoting industry-wide uptake.

Accuracy Improvement through BIM/CAD Data Integration

Behind AR panel placement verification lies smooth integration with design data. Modern AR applications can directly import digital data such as design drawings and 3D models and overlay them on-site. For example, CAD drawing data (DWG/DXF, etc.) and BIM models created by designers can be loaded into the app and displayed in AR. This allows faithfully reproducing detailed design plans on-site without simplifying them.

Traditionally, creating site layout drawings or entering coordinate lists into surveying equipment involved extra work, but CAD/BIM-integrated AR eliminates that. Once the design data is available, AR automatically displays it at the correct locations in the field, ensuring office and site always share the same information. When design changes occur, updating the data immediately reflects in the AR display on-site, enabling construction to proceed according to the latest plan without transmission errors.

Furthermore, using BIM models enables checking not only panel placement but also related structures, cable routes, and equipment on AR. For example, showing racking structural models and cable routing derived from BIM data allows checking interactions with auxiliary works at the same time as panel installation. Thus, AR–BIM/CAD integration is key to directly linking design accuracy with construction accuracy and closing the gap between drawings and the actual site.

Reactions at the Solar Expo and Exhibitors’ Initiatives

At the Solar Expo, AR construction support technology drew intense interest from visitors. Many contractors, designers, and municipal officials visited booths and watched smartphone-based AR demos intently. One booth featured the tagline “Your smartphone becomes a centimeter-class surveying instrument!” and live demonstrations of AR guidance using a smartphone fitted with a small accessory. When staff mirrored the phone screen onto a large display and showed virtual lines and points on the exhibition floor, observers were amazed to see CG guides fixed precisely on the floor even though nothing physical existed there.

Visitors frequently asked whether such precise positioning was really possible with a smartphone and how reliable AR accuracy was. Staff patiently explained while walking around the demo area that simply launching the dedicated app and holding the device allowed centimeter-level positioning instantly, and that they used correction signals from Japan’s quasi-zenith satellite system Michibiki (CLAS) to maintain high accuracy even in mountainous areas. Watching the demo where the AR display hardly drifted as the phone moved, attendees peered closely at the screen. Comments like “I’ve never seen AR that doesn’t drift” and “This looks ready for actual site use” were common, and the technology made a strong impression across experience levels, from novices to veterans.

The expo also featured seminars on themes such as digital construction management and smart surveying, where AR technology was discussed. Presentations introduced real-world AR deployments at construction sites, drawing engaged audiences. Q&A sessions focused on practical concerns like implementation costs and how to import existing design data, reflecting high industry interest. Exhibitors used individual consultations and hands-on experiences at their booths to promote the advantages of their AR solutions, and the entire Solar Expo buzzed with interest in cutting-edge construction support technologies.

Reported Effects from AR Adoption: Use Cases

Companies that have implemented AR for panel placement verification have already reported remarkable effects. In one solar construction company, panel installation errors decreased by about 80% after adoption, and the time required for layout explanation and client approval was reduced to half of previous durations. By sharing an accurate pre-visualization via AR, on-site rework drastically decreased and stakeholder consensus accelerated, contributing significantly to overall schedule compression and cost reduction. A site manager commented that compared to the days of showing drawings and explaining verbally, visual presentation sped things up, highlighting improved communication efficiency.

In another case, a novice worker completed layout marking in a short time following AR guides with accuracy comparable to experienced staff. This allowed standardizing processes that had depended on veterans, increasing staffing flexibility. These use cases demonstrate that AR is not merely a novelty but a practical tool that dramatically improves on-site productivity and quality. With measurable results such as reduced installation errors and smoother communication, more companies are expected to adopt AR going forward.

LRTK Simple Surveying Technology Supporting AR Placement Accuracy

Backing the high accuracy of AR panel placement verification are modern simple surveying technologies. A typical example is a solution called “LRTK,” which, using a small device attached to a smartphone and a dedicated app, enables anyone to easily achieve centimeter-level positioning. LRTK employs an RTK-GNSS (real-time kinematic satellite positioning) approach and leverages correction information such as the centimeter-class positioning augmentation service CLAS from Japan’s Michibiki, providing 1–2 cm positioning accuracy nationwide outdoors.

Usage is simple: attach the device to the smartphone and launch the app. High-precision positioning begins in just a few tens of seconds, after which pointing the device to a point immediately records its precise coordinate values. No complex manual calculations or communication setup are required, and acquired points are automatically shared to the cloud, eliminating the need to bring measured values back to the office for re-entry. With LRTK, reference-setting tasks that once required a two-person team operating a total station can now be completed by a single person walking with a smartphone.

This high-precision smartphone positioning plays a crucial role in AR placement verification. To align AR displays exactly with real-world positions, it is necessary to know the device’s current position precisely; LRTK makes this possible. In other words, it is because of LRTK that “AR without positional drift” can be realized. On sites using LRTK, users report that “AR lines remain trustworthy without shifting, allowing us to work confidently.” This is because LRTK continually corrects the smartphone’s position to centimeter precision, keeping AR objects correctly anchored in real space.

Additionally, LRTK is useful in various on-site scenarios beyond AR placement checks. Using built-in LiDAR or cameras, it can perform 3D point cloud scanning of the site, overlay obtained point cloud data with design models to check as-built conditions and progress, and function as an all-purpose surveying and measurement recording tool. Since all this is completed with a single smartphone, LRTK is often called a “pocket-sized all-purpose surveying instrument.” Its small, lightweight nature makes it easy to carry on site and a reliable ally for construction managers overseeing multiple sites.

Thus, advanced positioning technologies like LRTK are the unsung pillars supporting AR construction support. Because sophisticated technologies operate invisibly in the background, users enjoy a comfortable and highly accurate AR experience without conscious effort. With further refinement of positioning devices and AR app integration, solar power construction sites will evolve toward a level where failures and rework are effectively eliminated. The AR panel placement verification technology that drew attention at the Solar Expo, supported by these underlying technologies, is certain to robustly drive DX in the renewable energy industry.