No More Doubt About Pile Locations: Why You Should Use Smartphone Guidance for Solar Construction

In recent years, driven by the push for renewable energy, construction of solar power facilities has been accelerating across the country.

On solar construction sites, driving a vast number of piles into precisely the right locations is indispensable. If pile locations in the ground are off, assembling the mounting structures (that support the panels) can be impeded, and there is a risk of defects in the installed equipment after construction. Furthermore, if the spacing between rows is incorrect, panels may cast shadows on each other and reduce power generation efficiency, or the maintenance walkways may not be wide enough. Managing many pile locations over a large site is not easy, and traditional manual methods or surveying equipment used for marking pile positions carry an inherent risk of mistakes. This article explains the risks of pile-positioning errors that commonly occur on solar construction sites and the limits of conventional methods, and introduces an emerging solution: smartphone guidance. This technology, which allows operators to intuitively identify pile locations while looking at a smartphone screen, enables even inexperienced workers to perform unambiguous pile positioning, dramatically improving construction efficiency and accuracy.

Risks of pile-positioning errors and limits of conventional methods

Each pile that supports the solar panel mounting structure must be driven into its designated design location for the overall structure to be stable. If even one pile is misplaced, the spacing relative to adjacent panels will be off, placing undue stress on the support structure, or holes for rails and brackets may not align, causing problems after installation. Re-driving piles is time-consuming, and removing and re-driving already installed piles incurs additional time and cost. Pile-positioning errors are a serious risk that can lead to reduced on-site productivity, schedule delays, and extra expenses. In fact, problems caused by mislocated piles occur repeatedly at sites nationwide, causing many construction managers headaches.

So why do pile-positioning errors occur? Underlying causes include the limitations of traditional pile-marking methods. A common approach is for a surveying team to visit the site with construction drawings and mark pile locations by measuring distances from reference points with a tape measure or a transit (surveying instrument). However, solar sites are often large and uneven, so manual layout marking inevitably results in mistakes and deviations. For example, measuring long distances with a tape can accumulate errors of several centimeters, markers or stakes can be obscured by weeds or soil and be lost, and even when using surveying instruments, two or more people are usually required and operation demands specialized knowledge. On busy sites, mismeasurements can occur due to poor communication or missed checks, so relying solely on conventional methods makes it difficult to guarantee pile-placement accuracy. Moreover, with fewer veteran workers and increasing labor shortages, there are limits to continuing precision work that depends on individuals’ intuition and experience.

Examples of common issues with traditional pile-marking methods:

• Cumulative measurement errors over long distances causing positional shifts

• Marks for pile locations being erased by weather or hidden by vegetation and thus lost

• Surveying requiring multiple people, increasing labor costs

• Measurement errors due to instrument operation mistakes or communication failures

• Positional shifts caused by misreading drawings or transcription errors on site

Intuitive, high-precision pile placement with smartphone guidance

A trump card for solving these issues is on-site smartphone guidance technology. Modern smartphones, in addition to GPS, can utilize satellite positioning correction technology called RTK (Real Time Kinematic) to measure current position with centimeter-level accuracy—previously achievable only with specialized equipment. By attaching a dedicated high-precision GNSS antenna to a smartphone or receiving correction information from a base station over the internet, pile positions can be identified without deviation. In other words, a smartphone can serve the role of a high-precision surveying device, and it can now be brought to the site as a tool anyone can operate.

Smartphone-guided pile marking also excels in its intuitiveness. The target pile locations appear on the screen as map markers or AR (augmented reality) markers, and users can move toward the specified coordinates just like navigating to a destination in a map app. For example, the smartphone can display arrows or guide lines and instructions like “move 〇〇 cm north,” allowing the user to walk to the exact pile location with pinpoint accuracy. No complex surveying knowledge or calculations are required, and inexperienced workers can operate it intuitively, so you literally will no longer be unsure where to place piles. What used to require painstaking surveying can now be completed by simply looking at a smartphone screen—an innovative method that dramatically improves efficiency and accuracy in solar construction.

Moreover, GNSS-based guidance is effective even in poor-visibility environments. In places where reference lines cannot be drawn due to obstacles or vegetation, the smartphone continuously indicates current and target locations, allowing users to navigate around obstacles and still reach the exact designated coordinates. Even in mountainous areas outside mobile coverage, smartphones can maintain high-precision positioning by using augmentation signals from satellites, enabling stable guidance at remote solar sites.

Smartphone guidance is easy and low-cost to introduce

The latest smartphone-guidance systems also score highly for ease of deployment. All that’s needed is an everyday smartphone, a compact high-precision GNSS receiver, and a dedicated app. Attach the pocket-sized device to the smartphone, and the field becomes an instant high-precision positioning smart terminal. Heavy tripods and setup time are unnecessary, minimizing surveying preparation time. The equipment is easy to carry, so marking piles across a wide solar site is not burdensome.

Operation is simple, and dedicated apps feature intuitive interfaces. Anyone familiar with map or camera apps can quickly use them without special training. Since users just follow on-screen arrows or AR markers, even older workers can adopt the technology without resistance. Also, because smartphones are used, there’s less need to buy expensive surveying equipment or outsource to surveying experts, making it attractive for low-cost startup. It’s easy to prepare the number of devices appropriate for site scale, and a one-device-per-person approach is becoming common.

An example workflow:

• Prepare coordinate data: Load pile coordinate data into the smartphone app or cloud based on the construction plan

• Start guidance: Launch the app on site and select the point (pile location) to guide to

• On-site guidance: Move according to the arrows and distance shown on the smartphone until reaching the specified pile position

• Mark the pile location: Mark the target point and, if necessary, indicate the position with a temporary stake or spray paint

• Verify with AR: Use the camera-based AR display to confirm the virtual pile center aligns with the mark and fine-tune if there is any deviation

• Drive the pile and record: Once position is confirmed, drive the pile and save positioning data and photos to the cloud to complete the record

Smartphone guidance enables safe single-person operations

One major benefit of smartphone-guided pile positioning is that a single person can complete the work. Traditionally, accurate pile marking required several people to operate surveying equipment or hold long tapes at both ends. With smartphone guidance, one worker can walk the site with a smartphone in hand and mark pile locations sequentially. Even without assistants or experienced surveyors, anyone can use their own smartphone to achieve high-precision positioning, contributing to labor-saving surveying and pile marking. Performing positioning alone also streamlines work compared to having multiple people call out measurements, reducing wasted movement and waiting.

Single-person operations are reliable because the smartphone continuously displays deviations from the target coordinates numerically and graphically for real-time verification. For example, when a worker reaches a pile point, the smartphone may display “Error from target point: 2 cm,” and if within tolerance, the pile can be driven immediately. There is no need to ask someone to re-measure or rely on a guess like “around here.” As a result, small crews can carry out pile driving confidently and efficiently, improving overall site productivity and peace of mind.

In practice, some solar sites that adopted smartphone guidance reported that the days required for pile marking dropped to less than half of traditional methods. This technology, which achieves both labor reduction and efficiency improvements amid labor shortages, is expected to spread further.

Additionally, pile-driving machine operators themselves can use smartphone guidance. Previously, operators needed a ground assistant to direct pile locations, but if the operator can view pile positions on a smartphone from the cab, work can proceed safely without an assistant. Reducing personnel around heavy equipment also lowers the risk of struck-by incidents and other accidents.

Prevent construction errors with AR-based pile-center verification

Smartphone guidance also excels at on-site construction verification before and after pile driving. When viewing the site through a smartphone camera, design pile positions and heights are overlaid as AR (augmented reality) elements. For example, after driving a pile, pointing a smartphone at it will instantly show whether the virtual pile center (the centerline) displayed on-screen matches the actual driven pile. If there is a deviation, it can be adjusted immediately, so pile-center misalignment is not overlooked and can be corrected on the spot. It’s also easy to use AR to display virtual straight lines or partition lines for a row of piles to check whether any single pile is out of alignment.

Moreover, when design pile positions are physically difficult to install due to terrain or boundary constraints, virtual piles in AR can be used to detect and share issues in advance. For instance, if subsurface obstacles are present or piles cannot be driven near a property boundary, virtual piles allow stakeholders to share information early and consider countermeasures.

This visual verification via AR greatly contributes to preventing construction mistakes. Traditionally, errors were often discovered only after re-surveying following pile driving or when components failed to fit in later stages. But with smartphone AR, on-site verification of as-built conditions enables early detection and correction of errors, minimizing rework. The result is improved quality control and enhanced overall safety on site. The assurance of not leaving invisible misalignments unaddressed benefits both workers and construction managers alike.

Cloud integration creates a seamless link between field and office

As a platform supporting smartphone guidance, cloud integration plays a key role. Pile coordinate data and survey results can be managed centrally in the cloud, allowing on-site information to be shared immediately with the company and subcontractors. For example, construction managers can check pile measurement data in real time from an office PC via the cloud and verify for deviations. Because everyone can view the same up-to-date data instead of relying on paper drawings or verbal reports, communication errors are reduced and project management proceeds more smoothly.

If a list of coordinate data for the construction plan is uploaded to the cloud in advance, on-site smartphone apps can call that data for guidance. When design changes occur, updates are immediately reflected on field devices via the cloud, preventing piles from being driven based on outdated information. Conversely, saving as-built pile positions and photos to the cloud helps with the preparation of inspection documents and as-built management. Cloud storage also serves as a backup, providing peace of mind in the event of device loss or other incidents. In this way, cloud integration connects the field and office seamlessly, further improving the efficiency and reliability of pile-driving work in solar construction.

Conclusion

Smartphone-guided pile-positioning technology brings many benefits to solar construction sites. In particular, using an RTK positioning system on smartphones such as [LRTK](https://www.lrtk.lefixea.com/lrtk-phone) can achieve the following effects:

• RTK-guided pile coordinates: Navigate to pile positions with centimeter accuracy so even inexperienced personnel can place piles without hesitation

• AR-based pile-center verification: Overlay virtual and actual piles to detect and correct centerline deviations on the spot

• Labor-saving surveying by a single person: Significantly reduce the need for specialist staff and enable efficient single-operator positioning

• Prevention of construction mistakes: Reduce human error through digital guidance and immediate verification, aiming for zero rework

• Cloud-based information sharing: Synchronize data between field and office to share progress and measurement results in real time

Sites that have implemented smartphone guidance report feedback such as “work became dramatically more efficient” and “we were surprised by accuracy comparable to specialized equipment,” and the conventional wisdom on site is beginning to change.

With the familiar combination of smartphones and compact high-precision GNSS devices, high-precision pile positioning that was once difficult is now achievable by anyone. By advancing construction DX to match the times, solar power construction sites have the potential to dramatically improve productivity, quality, and safety. There’s no need to be unsure about pile locations anymore. Consider adopting smartphone guidance as a new partner on site to achieve efficient and reliable solar construction. Riding the wave of the Ministry of Land, Infrastructure, Transport and Tourism-led i-Construction (ICT construction), smartphone-guidance technology is likely to become a new standard in solar construction sites.