One-person Surveying Is Possible! Labor Savings and DX of 3D Surveying Realized with LRTK

In recent years, the construction and surveying industries have rapidly adopted 3D surveying. Point cloud data, which can digitally capture terrain and structures in their entirety, makes it possible to visualize complex site conditions that were difficult to grasp with traditional 2D drawings or photographs. As a result, 3D data is attracting attention across design, construction, and maintenance. Until now, however, many people have associated 3D surveying with expensive laser scanners or drone (UAV) photogrammetry. These approaches often required specialized surveying teams and significant upfront investment, making them a high barrier for small and medium-sized sites.

Now, new technologies are dramatically lowering these barriers. Using a solution called "LRTK," which combines a smartphone with a compact RTK-GNSS receiver, you can perform 3D surveying with centimeter-level accuracy with surprising ease. Tasks that previously required multiple people can be done as one-person surveys using LRTK. This greatly reduces labor and time, streamlines on-site surveying operations (labor savings), and — because the acquired data is already digital — accelerates DX (digital transformation). This article explains the benefits and practicality of 3D surveying with LRTK, comparing it to conventional technologies.

How 3D Surveying Is Changing Sites and the Latest Trends

First, what is 3D surveying? The core of 3D surveying is point cloud data — a 3D dataset that represents objects and terrain surfaces as a collection of countless points. By assigning X, Y, and Z coordinates (and often color information) to each point, you can accurately record the site's shape as it is. There are several acquisition methods, such as laser scanners, photogrammetry, and MMS (mobile mapping systems), but they all share the ability to capture extensive 3D information in a short time. For example, point clouds of an urban intersection captured by a state-of-the-art terrestrial laser scanner can reproduce fine details of buildings and roads with a high density of points.

The major advantage of these 3D surveying technologies is that they allow you to digitally record the site in its entirety. Point clouds can capture complex terrain and as-built conditions that planar drawings and limited photographs cannot, enabling seamless data capture for later slicing into arbitrary cross-sections or remeasuring required dimensions — in other words, reusable data. From a single set of 3D data, you can visualize discrepancies between design drawings and actual construction, or automate volume and quantity calculations, dramatically improving the accuracy and efficiency of construction and as-built management. For example, on one site, a LiDAR survey using a tablet to inspect cracks in a structure reduced tasks that used to take 1–3 days for photo compositing and drafting down to a few minutes, cutting outsourced inspection work by 30–40%. In this way, 3D surveying is fundamentally transforming how site records are kept.

Driven in part by the Ministry of Land, Infrastructure, Transport and Tourism’s *i-Construction* (ICT construction) initiative, drone- and mobile-device-based 3D surveying is rapidly penetrating worksites. Site measurements that once relied on veteran surveyors are becoming tools anyone on site can handle thanks to advances in digital technology. One of the most recent trends is the emergence of simple 3D surveying using smartphones and RTK — LRTK.

"3D Surveying Anyone Can Do" with a Smartphone + RTK

Modern smartphones are equipped with LiDAR sensors that can scan surrounding spaces and instantly acquire point cloud data up to several meters away. By combining a smartphone’s built-in LiDAR with high-precision RTK-GNSS (real-time kinematic) positioning, 3D surveying that once required specialized equipment has been transformed. Specifically, by attaching a compact RTK-GNSS receiver (an LRTK device) that can be mounted on iPhones or iPad Pros and receiving correction data from a base station over the network, the smartphone itself becomes a surveying device with centimeter-level accuracy.

With smartphone + RTK surveying, you can continuously scan the surroundings simply by walking while holding the phone, and every point in the resulting point cloud is assigned a global coordinate (absolute coordinates in a world geodetic system). For example, during a small bridge inspection, a worker can hold the smartphone under girders and piers to LiDAR-scan the structure and capture the entire 3D point cloud alone. Because the RTK receiver from LRTK continuously corrects the phone’s position to centimeter-level accuracy, there is no need to worry about gradual drift or distortion of point cloud data while moving. Since accurate coordinates are assigned to every captured point, measurement accuracy is maintained even over extended ranges, so you can confidently measure as-built conditions of long objects and distances between distant points.

In practice, the fact that anyone can easily capture coordinate-tagged point clouds with a single pocket-sized device is revolutionary. Surveying work that used to require tripods or mounted equipment can increasingly be completed with just a smartphone. LRTK devices weigh only a few hundred grams, include built-in batteries, and require no cumbersome cable connections. Essentially, just by "holding up your smartphone and walking," you can create accurate 3D models of terrain and structures in a short time. Because the system is so easy to use that even non-licensed surveyors can operate it after minimal training, site supervisors and foremen have begun to adopt it themselves. LRTK, which enables anyone, immediately, to perform high-precision 3D surveying in the field, can be considered a new "best-fit" solution for many sites.

Comparison with Conventional Surveying Methods – Differences from TS, Drone, and GNSS Surveying

To clarify the advantages of one-person 3D surveying with LRTK, let’s compare it with conventional representative surveying methods.

• Total Station (TS) surveying: A standard for terrestrial surveying, TS can measure each point with high accuracy, but it generally requires two people — an instrument operator and a prism holder. Surveying a wide area with TS can take a long time because many points must be observed, increasing labor. Because the terrain is often interpolated between measured points, sparse measurements limit the ability to capture terrain details. It can also be hard to track later who measured which points, leaving reliance on notes or photos.

• UAV (drone) photogrammetry: A method that uses aerial photos taken by a drone-mounted camera to generate 3D terrain models. It has the advantage of covering wide areas in a short time, and tasks that once took days can sometimes be completed in a few hours. However, aviation laws and pilot qualifications are required, and drones cannot be used in urban areas, indoors, or under bridges — in other words, environments where drones cannot fly. Ensuring photogrammetry accuracy may require many ground control points, and data processing after flight can take time. Areas obscured from view, such as the back sides of structures or ground covered by trees, cannot be captured in the point cloud and may require additional surveying later.

• Conventional GNSS surveying: Surveying with GPS/GNSS receivers can be done by one person when satellite visibility is good. Using network RTK services or a rover + base setup can provide centimeter-level positioning in real time. However, traditional GNSS surveying fundamentally consists of repeatedly acquiring coordinates point by point, so many measurement points are needed to capture an entire surface. GNSS reception can suffer interruptions or errors in certain environments, and precision may be inadequate in built-up areas or forests. Dedicated GNSS equipment is also expensive, and equipping multiple units can be a significant cost burden.

Each conventional method has its advantages, but they all have limitations in terms of personnel, time, and cost. On the other hand, smartphone surveying with LRTK can acquire surface 3D data in a short time with only one person, resolving many of these issues. For example, a site that took three days with TS might be completed in half a day with drone photogrammetry. In some tests using drones equipped with laser scanners, measurement time was reduced to 1/6 of conventional methods, cutting overall work schedules to less than half. With LRTK, you can achieve comparable efficiency gains in advanced 3D measurement using a far more accessible approach. An additional advantage of using a smartphone is that you can check results on the spot. If you missed necessary points, you can immediately remeasure, and you can calculate dimensions or volumes on the point cloud right away, reducing the need to bring data back to the office for redrafting and recalculation.

Benefits of Adopting LRTK – Labor Savings, High Accuracy, and Low Cost

Based on the above, here are the main benefits of introducing 3D surveying with LRTK.

• Significant labor savings (efficiency): Surveys that used to require two to three people can be completed by one person, greatly simplifying personnel arrangements and scheduling. With the same workforce, more surveying tasks can be handled, reducing labor costs and contributing to work-style reforms. Because point clouds capture surface information all at once, re-measurement is reduced, cutting rework. As noted earlier, there are examples where 3D measurement reduced tasks from days to minutes, showing large productivity gains.

• Centimeter-level accuracy: LRTK ensures positioning accuracy within a few centimeters using RTK-GNSS. This satisfies the precision required by the Ministry’s as-built management guidelines (roughly ± a few cm) and is sufficient for typical civil engineering surveying and as-built verification. Because measurements can be repeated easily, it's practical to adopt an operational workflow of frequent measurements to verify as construction progresses, allowing rapid work while maintaining accuracy on site. Variations due to reception environment or weather should be monitored, but mitigation measures are the same as for conventional GNSS surveying and do not require special skills. When necessary, validating with known control points can provide confidence in the results.

• Low-cost introduction: Historically, introducing 3D laser scanners or high-end UAV surveying equipment required investments in the hundreds of thousands to millions of yen. In contrast, surveying with a smartphone + LRTK greatly reduces initial costs. If you already have a LiDAR-capable smartphone or tablet, you only need a GNSS receiver. Even if purchasing a new device and receiver, total costs are said to start from around ¥200,000–¥300,000, making it far more economical than acquiring dedicated surveying equipment. Although LRTK Phone device prices have not been publicly announced, they are described as being at a "very affordable price so that each person can have one," making it feasible to equip all workers without a heavy budget burden. Operating costs are also minimal, limited mostly to cloud service fees and communication charges, and software updates are delivered online, keeping long-term running costs low.

• Ease of use without specialist knowledge: LRTK’s simplicity is a major attraction. Following the surveying app's interface and pressing the appropriate buttons is enough to perform positioning and point cloud acquisition, meaning that even non-specialist staff can become proficient after brief training. Traditionally, analyzing survey results and drafting drawings required specialized software knowledge, but LRTK’s cloud services automatically plot data on maps and offer one-click calculations for distance, area, and volume. The app also supports complex coordinate transformations and reference plane settings, so those unfamiliar with equipment or coordinate systems need not struggle. It’s said that "with LRTK, all site notetaking becomes unnecessary," reflecting how much it digitizes previously manual measurement and calculation tasks. In short, you don’t need to hire specialized personnel to perform high-precision surveying — your existing staff can handle it.

The Future of Site DX Enabled by 3D Surveying Data

Point cloud data that can be easily obtained with LRTK becomes a powerful enabler for site DX (digital transformation). On-site management that used to rely on paper drawings and verbal explanations becomes instantly shareable and intuitively understandable with 3D data. For example, overlaying a design model on a point cloud captured during construction allows immediate verification of whether the as-built condition matches the design. Automatically generating cross-sections or heat maps (error distribution maps) from point clouds for quality control is also straightforward. This not only streamlines surveying and inspection processes but also facilitates data-driven, objective consensus building, improving communication between clients and site teams.

Because data captured with LRTK is uploaded to the cloud immediately, stakeholders in remote locations can share information in real time. Point clouds and coordinate information measured on site can be checked on PCs at the office or headquarters instantly, substantially speeding up decision-making. Recently, advanced examples have appeared where point clouds are transmitted in real time from drones or robots for remote headquarters-based supervision. This enables situation awareness without sending people into hazardous areas, improving safety and boosting productivity by reducing travel time.

LRTK also pairs well with AR (augmented reality) technologies, opening up new possibilities for site DX. By displaying absolute-coordinate point clouds or design data as AR overlays through a smartphone, you can visualize buried pipes before excavation or share completed-imagery on site, making such applications simple. Portions of work that once relied on craftsmen’s intuition can now be visualized digitally, allowing less experienced workers to operate with greater confidence. By integrating 3D data from LRTK with various digital tools, it becomes possible to promote comprehensive DX covering construction management, inspection, and maintenance.

In one municipality, for example, equipping all public civil offices with 3D point cloud processing systems to digitize as-built management for roads and rivers led to dramatic improvements in safety and productivity. A major construction company also demonstrated an automated surveying workflow using quadruped robots and drones equipped with LiDAR to measure inside and outside tunnels, instantly sharing point clouds remotely. This allowed headquarters staff to monitor site progress and as-built conditions without being on-site, moving toward the possibility of remote construction management without manned patrols. Adopting LRTK as an entry point for 3D surveying and digital technologies at your site can be the first step toward these advanced practices.

Conclusion: Start 3D Surveying to Achieve Labor Savings and DX

3D surveying using smartphones and point cloud technology overturns the traditional image of being "expensive and specialized," evolving into an accessible tool anyone can use. With the arrival of LRTK, even small and medium-sized sites can easily perform 3D surveying and leverage the data. The benefits range from improved efficiency in routine tasks such as as-built management and earthwork calculations to enhanced quality control through more accurate site records. Above all, point cloud data that digitally captures the site "as it is" becomes an indispensable new asset for future construction management.

That said, introducing new technology into the field naturally raises concerns such as "Can we really use it effectively?" or "Will it deliver the expected accuracy?" LRTK was developed as a field-oriented solution to dispel such concerns. By simply attaching a pocket-sized device to your smartphone, it automatically achieves cm-level positioning and point cloud acquisition, and data is shared instantly via the cloud. Prices are far lower than traditional surveying equipment, making LRTK appealing and accessible for small companies and local governments. If you feel "I’d like to try it on my site," check [the LRTK official site](https://lrtk.lefixea.com/) first. They offer consultation on initial deployment and demo requests, so you can experience the convenience and accuracy on an actual site.

Now is the time to adopt 3D surveying at low cost and use it to improve your site’s productivity, safety, and quality management. Accurately recording the site in 3D and fully leveraging the data narrows the gap between design and construction and leads to safer, more efficient site operations. Take this opportunity to take a new step and ride the wave of site DX — you’ll soon find yourself saying, "This really works for our site!"

LRTK dramatically improves on-site surveying accuracy and work efficiency. Details about this solution, ideal for the i-Construction era, are available on the official website. For product questions or consultations about implementation, please feel free to contact us via the [inquiry form](https://www.lrtk.lefixea.com/contactlrtk). Use LRTK to take your site to the next stage.