One-person Work Made Safe! Streamlining Solar Construction Surveying with Smartphone RTK

Surveying Challenges at Solar Construction Sites

Surveying is an indispensable step at solar power plant (so-called mega-solar) construction sites. Accurate survey data are required for many purposes: site development planning for large areas, staking out panel installation positions, as-built surveys after construction, and earthwork volume calculations. However, traditional surveying methods have significant challenges.

First, surveying large areas requires enormous time and manpower. Surveying a mega-solar scale site (several hectares or more) with total stations or conventional GNSS equipment can force a team of multiple people to work for many days. In mountainous or sloped terrain with poor line-of-sight, it takes even longer, placing a heavy burden on labor costs and project schedules.

Next, the issue of dependency on skilled technicians cannot be overlooked. Setting up total stations and converting measurement data into drawings require advanced knowledge and experience, meaning many tasks must rely on seasoned surveyors. With labor shortages and an aging workforce across the construction industry, securing experienced surveyors is difficult, and surveying work tends to become dependent on specific individuals. Outsourcing to external surveying specialists also increases costs and makes frequent survey updates difficult.

Furthermore, inefficiencies in handling and sharing survey data have been a problem. Traditionally, measured point coordinates were written by hand in a field notebook, then entered into a PC back at the office for drawing — a common workflow. On large sites, the number of measured points becomes enormous, and simply organizing data manually requires considerable effort and time. Because field data could not be immediately shared with construction managers or designers, there was a time lag before survey results were fed back into design and construction, which could prolong the overall schedule.

In this way, surveying at solar construction sites has faced the dual challenges of “workload due to scale” and “inefficiency of traditional methods.”

The Era of Solo Surveying Opened by Smartphone RTK

One emerging solution to these challenges is the approach of solo surveying using smartphone RTK. As the name implies, smartphone RTK involves attaching a compact high-precision GNSS receiver to a smartphone and using RTK (Real-Time Kinematic) technology to turn the phone into a centimeter-level surveying instrument.

RTK positioning uses correction information distributed from known reference stations such as continuously operating reference stations to correct positioning errors from multiple satellite signals, such as GPS and Michibiki (Quasi-Zenith Satellite), in real time to within a few centimeters. RTK surveying, which once required stationary, expensive GNSS units or base stations, has recently become feasible with the convenient combination of a smartphone + pocket-sized receiver thanks to technological advances.

With smartphone RTK, surveying tasks that previously required a two-person team can be completed by a single person. Even without a veteran surveyor, site staff can walk the site with a smartphone in hand and quickly measure points one after another. Carrying a pocket-sized, easy-to-use surveying device and taking measurements whenever needed — this is what smartphone RTK enables.

The efficiency gains from smartphone RTK extend beyond just the surveying task. Shorter surveying time leads to shorter project durations and contributes to earlier revenue realization for solar power projects. If one person can quickly complete as-built surveys or staking, it becomes easier to work in parallel with other construction tasks, improving overall productivity. Truly, “solo surveying” is becoming a revolutionary practice that changes the norms at solar construction sites.

Main Benefits Brought by Smartphone RTK Surveying

Introducing smartphone RTK on site can be expected to bring the following benefits to surveying operations in solar construction:

• Efficiency and labor reduction through one-person operation: With smartphone RTK, surveying that once required multiple people can be done by a single operator. When each worker carries surveying tools and can measure points concurrently, surveying large sites speeds up dramatically. For example, where other crews had to wait for a surveying team to finish, individuals can take measurements autonomously, reducing idle time and significantly improving project-wide efficiency. The labor cost savings from reduced manpower are substantial, making this an effective measure against workforce shortages.

• Improved quality with centimeter-level accuracy: RTK positioning achieves very high accuracy, within a few centimeters, which enhances precision for tasks like locating solar panel racking and setting foundation piles. Compared to traditional tape-measure staking based on experience and intuition, errors can be minimized to the greatest extent, improving construction accuracy and quality control. In fact, reports indicate that when an RTK receiver for smartphone RTK is mounted on a pole, horizontal position errors can be less than 1 cm, matching the accuracy of professional surveying equipment in some cases.

• Reduced mistakes through digital measurement: Smartphone RTK records measured values digitally on the smartphone and automatically handles coordinate transformations and averaging. Handwritten field notes and human reading errors are eliminated, substantially reducing survey mistakes caused by human error. For example, tapping a positioning button instantly records latitude, longitude, and elevation and automatically converts and saves them in the project’s coordinate system, such as a plane rectangular coordinate system. With no risk of digit misreading or entry errors, one-person operations can reliably ensure survey quality.

• Easy to learn and usable by anyone: Because smartphone RTK runs on smartphone apps, it offers intuitive, simple operation even for those unfamiliar with specialized equipment. Following on-screen prompts and pressing buttons is often enough to complete a survey, with results displayed in real time. Unlike traditional surveying instruments that require complex setup or difficult procedures, smartphone RTK can be learned quickly by newcomers or staff with limited surveying experience. As a tool that “anyone who has used a smartphone can quickly master,” it helps address technician shortages and the problem of work becoming dependent on particular individuals.

• Convenient data sharing through cloud integration: Survey positioning data and results collected on site can be uploaded and shared directly from the smartphone to the cloud. Position data and notes are automatically plotted on a web map, eliminating the need for manual office input from returned field notes. As long as there is internet access, the field and the office are instantly connected, allowing construction managers and designers to grasp the situation in real time. This speeds feedback from surveying to design and construction and streamlines team information sharing. There is no longer a need to exchange paper drawings or USB drives, and remote review and instruction become possible, making remote site supervision effective.

• Visual support and improved safety via AR technology: AR (augmented reality) features combined with smartphone RTK also provide significant on-site benefits. By overlaying models or stake positions from design drawings onto the actual scene through the smartphone screen as an AR display, workers can intuitively understand “what should be installed where.” For example, projecting a 3D model of a solar panel rack onto the ground via AR enables sharing of the on-site completion image if installed as planned, helping prevent construction errors and misunderstandings. Because smartphone RTK provides high-precision positioning, the virtual stakes shown in AR rarely deviate from the actual positions, allowing the pile-driving positions to be made as close to zero error as possible. These features also contribute to improved on-site safety. Scanning and visualizing buried elements (such as conduit) in AR and sharing them with equipment operators reduce the risk of damaging obstacles, and even with small crews, everyone can proceed with the same shared image, helping prevent accidents caused by human error.

As described above, solo surveying with smartphone RTK offers benefits across the board — from efficiency and labor reduction to accuracy assurance and safety enhancement. On solar power installation sites, this new surveying method strongly supports DX (digital transformation), becoming the key to enabling fast and accurate construction with limited personnel.

Smartphone RTK Surveying Realized by LRTK

To fully leverage the advantages of smartphone RTK, choosing a reliable tool is essential. Enter LRTK, an all-in-one surveying device developed by Reflexia. LRTK is an ultra-compact RTK-GNSS receiver that attaches to a smartphone, designed so anyone can easily perform centimeter-accurate positioning and various measurements.

Attach LRTK to a smartphone and the device is transformed into a high-precision surveying instrument. Although it is a pocket-sized device weighing only a few hundred grams, it supports Michibiki (CLAS) and network RTK, enabling stable positioning even at sites where mobile signals are weak, such as mountainous areas. Using the dedicated “LRTK app,” single-point positioning can be done with one tap, and plane rectangular coordinates and elevation (geoid height) are automatically converted and displayed. Each measurement can be tagged with a title or note, and all captured information can be uploaded and shared to the LRTK cloud with one click.

LRTK also features AR functions and point cloud measurement capabilities, allowing users to capture 3D point cloud data of the site using the smartphone camera and LiDAR, and to overlay design models in AR to check positional consistency — enabling a wide range of tasks with a single device. For example, after measuring control points, you can immediately 3D-scan the surrounding terrain with your smartphone and overlay CAD design data on the resulting point cloud for alignment checks. The cloud service provides automatic alignment of point cloud data with design models and instant earthwork volume calculations, making it a major advantage that surveying, design, and construction management can all be completed on a smartphone.

For surveyors, construction managers, and site supervisors, smartphone RTK is becoming a reliable partner that allows them to confidently entrust solo work. Especially by using products like LRTK, surveying operations for solar construction can be dramatically streamlined, realizing a new era of construction that combines labor reduction and high precision. If you feel current site surveying has problems, consider adopting a smartphone RTK solution. With advanced technology on your side, make solar power plant construction sites smarter and safer.