Complete layout marking with just a smartphone! The full picture of a new era in civil surveying opened by LRTK

The importance of layout marking and on-site challenges

In construction and civil engineering, layout marking is the crucial initial process. If the lines and marks drawn on the ground or structures based on the design drawings are not accurate, every subsequent construction task will be affected. For example, if the foundation position or elevation is marked incorrectly, columns or walls may be misaligned or out of level, potentially requiring large-scale rework or repairs later. For this reason, layout marking is a key task that determines the quality and schedule of the work.

However, on-site layout marking involves many challenges. First, the process is time- and labor-intensive. On large sites or with complex structures, there are many measurement points, and even with several people it can take an entire day to finish layout marking. Next, the traditional method of manually measuring each point one by one inevitably allows small errors or oversights. Even experienced workers who work carefully find it difficult to achieve zero mistakes, and layout marking errors have always posed a risk of downstream construction mistakes and rework. Furthermore, the recent shortage of experienced veteran workers is a serious problem, and the transfer of skills to younger workers is not progressing. Because layout marking requires high accuracy, new solutions that reduce labor and prevent mistakes are urgently needed.

Traditional layout marking methods and their limitations

Until now, layout marking has relied on conventional technologies such as transits (optical surveying instruments) and tape measures, and even total stations. Each method has established procedures, but there are also many constraints and problems encountered on site.

• Layout marking with a transit + tape measure: The typical method uses two people, one setting up the transit to measure angles while the other measures distances with a tape and marks points. The equipment itself is relatively inexpensive, but the method depends heavily on manpower and requires experience. There is room for human error such as angle-reading mistakes or tape sag, and measurement errors can accumulate over wide areas. Working in scorching sun or on poor footing is physically demanding and requires attention to safety.

• Layout marking with a total station: Using a total station with electronic distance measurement allows one person to hold a prism while another measures and sights, simultaneously obtaining distance and angle. This greatly improves efficiency and accuracy compared to conventional methods, but it requires expensive dedicated equipment and skilled operators. Transporting and setting up the equipment is laborious, and it can be unsuitable for tight sites or high places. There are models with automatic tracking that enable single-person operation, but they are very costly. In short, even if a total station is introduced, cost and operation hurdles remain, and it is not something everyone can handle casually.

Thus, conventional layout marking methods are accompanied by effort and complexity to ensure accuracy. On sites, there has long been demand for a simple method that achieves “quick and reliable layout marking,” yet practical options were limited.

Advantages of smartphone RTK for layout marking

Recently, smartphone RTK positioning technology has been revolutionizing layout marking. By combining a smartphone with a compact GNSS receiver, centimeter-level positioning (half-inch accuracy) has become easily achievable on site, and the way layout marking is done is beginning to change dramatically. The notable advantages include:

• Single-person operation: With smartphone-based layout marking, there is no need to carry heavy tripods or special equipment and move around as a team. One person can walk the site and complete the marking at specified points. This reduces the effort of arranging personnel and helps address labor shortages.

• High accuracy and reduced errors: RTK positioning keeps errors within a few centimeters (within a few inches), enabling layout marking with accuracy far superior to manual methods. Guidance displays on the smartphone screen allow accurate positioning without relying on intuition or experience, so anyone can find the correct spot. As a result, point misplacement and marking errors decrease, lowering the risk of rework.

• Reduced work time: There is no time needed for equipment setup; you can start positioning and marking immediately after launching the app. Compared with traditional methods that measure and mark each point one by one, you can mark points rapidly in sequence according to instructions, achieving major time savings and enabling wide-area layout marking in a short time.

• Mobility and safety: Because the system is centered on a pocket-sized smartphone, work is nimble even in tight or elevated locations. There is no need to set up equipment on sloped or unstable ground, allowing safer and more flexible work. Surveying while moving is less burdensome, contributing to reduced physical fatigue for workers.

• Intuitive AR display: Arrows and virtual stakes (AR markers) are overlaid on the real-world view through the smartphone screen to visually indicate target positions. This allows on-site confirmation of drawing coordinates against the actual scene, so even first-time users can reach the target point without confusion. It is easy to operate the smartphone with one hand while marking with the other, making on-site handling especially convenient.

These advantages, which are not merely extensions of conventional methods, have made the era of “anyone can do accurate layout marking immediately” a realistic prospect. The solution that embodies smartphone RTK layout marking is LRTK.

Main functions and features of LRTK

LRTK is a groundbreaking device-and-app system that turns a smartphone into a versatile surveying instrument. By attaching a dedicated compact RTK-GNSS receiver to a smartphone and using the app, an ordinary smartphone transforms into a high-precision positioning and measurement tool for the field. With LRTK you can complete everything from surveying and layout marking to 3D scanning and data sharing with just this one device. The main functions worth noting are:

• Coordinate navigation: When you specify coordinates obtained from design drawings or known control points in the app, a navigation function guides the user to those points. Relying on arrows and the distance to the target displayed on the smartphone screen, you move toward the point; when you get close, a virtual stake mark appears on the screen to pinpoint the exact spot. Even without specialized surveying knowledge, you can locate target points accurately, enabling anyone to drive stakes and set positions precisely.

• AR guidance and design data display: This function allows design lines and models to be AR-displayed directly on the smartphone camera feed. For example, instead of drawing chalk lines on the ground, you can project design lines through the smartphone to align positions, or overlay a 3D model of the finished structure onto a structure under construction to check for missing elements or clashes. It is also possible to visualize underground buried pipes through AR after backfilling to confirm their positions. Based on high-precision positioning information, LRTK achieves AR projection without offset, making it easy for all stakeholders to share a common on-site image.

• High-precision point cloud scanning: LRTK integrates with a smartphone’s built-in LiDAR scanner or camera to acquire 3D point cloud data simply by walking around the site. Each captured point is tagged with latitude, longitude, and elevation, so the scan results directly align with the public coordinate system (World Geodetic System). It enables comprehensive measurement of wide areas in a short time, reducing the worry of missed points later. From understanding terrain shape to verifying as-built conditions and calculating volumes of embankment or backfill, being able to use high-precision point cloud data on site is a major advantage.

• Cloud integration and data sharing: Measured coordinates, point clouds, photos, and notes are automatically synced to the cloud. The moment layout marking or measurements are completed on site, the data are uploaded and can be checked in real time from office PCs. No specialized software is required; data are visualized on maps and 3D views in a browser, enabling immediate sharing with supervisors or clients at remote locations. Generating a shareable URL lets partner companies view and measure the data, greatly reducing communication loss between the site and stakeholders.

• As-built support and analysis: Managing as-built dimensions of completed structures is important in civil works, and LRTK makes as-built measurement simple. You can extract arbitrary cross-sections from captured point clouds to compare deviations from design shapes, and calculate volumes and areas on the spot, allowing immediate quality checks based on measurement data. Inspection work that used to be done manually by experienced staff can be digitized to improve efficiency and reduce labor. Since analysis can also be performed in the cloud, it’s easy to upload site data to headquarters for checking and prompt feedback.

The fact that these functions are realized within a single smartphone app is LRTK’s strength. All you need is a smartphone and a palm-sized receiver. Carried as one device per person, it can be taken out and used for surveying and layout marking whenever needed. Initial costs are lower than traditional surveying equipment, and because the operation is intuitive for both young and experienced users, organizational adoption is easier. It is truly a convenient trump card supporting on-site DX (digital transformation).

Complete workflow from surveying to layout marking, inspection, and sharing by one person

Introducing LRTK significantly changes on-site workflows. Previously, tasks were divided—survey teams measured control points, construction managers performed layout marking, and inspection staff measured as-built conditions after completion. With LRTK, a single technician can handle surveying, layout marking, as-built measurements, and data sharing in an integrated manner.

For example, a technician can arrive at the site in the morning, measure and confirm known points with LRTK, and then proceed alone to perform layout marking at various locations. There is no need to alternately consult paper drawings and surveying instruments; simply follow the instructions displayed on the smartphone and mark the site.

After finishing layout marking, the technician can immediately measure important parts’ as-built conditions using point cloud scanning and report to the office via the cloud the same day. Because the data collected on site are instantly shared with stakeholders, additional instructions can be received on the spot and potential rework areas corrected early. The traditional cycle of surveying → layout marking → inspection → reporting, which used to take several days, is dramatically shortened by LRTK.

Also, since LRTK’s operation is intuitive and requires no complicated setup, it can be used even by non-veterans. Young technicians with limited field experience can learn it quickly if they are comfortable with smartphones, enabling work previously left to specialist surveyors to be distributed across the team. Shifting from methods that depend on individuals to a system where anyone can measure helps mitigate the shortage of skilled workers. In other words, LRTK supports the shift to “smart construction” where each person can respond flexibly on site.

On-site use cases: from pile driving to structure installation

Now, let’s look at specific on-site applications of LRTK.

• Application to pile driving: LRTK is powerful when setting reference piles in roadworks and similar tasks. If design coordinates are pre-registered in the app, you simply follow the smartphone’s arrow guidance until you approach the position. When you get close, an AR stake appears on the screen to indicate the designated pile location. You then drive the actual pile into the ground at that spot. There is no need to repeatedly measure distance to determine positions, and the accuracy of each pile is reliably ensured. Pile-driving tasks that traditionally required a surveyor and a worker can now be done efficiently by one person.

• Application to structure installation: LRTK functions are also useful for aligning installations such as bridge bearings or prefabricated structures. For example, when installing a bearing plate on a bridge pier, you can AR-display the design position’s 3D model on the smartphone and adjust the actual part while comparing it with the model. Precise installations that used to rely on tape measures and “feel and experience” can now be performed while visually checking for misalignment via AR, enabling quick and highly accurate placement. It can also be used for pre-checking interference with surrounding objects by AR simulation during large equipment delivery and installation, aiding safety and planning. LRTK’s visual guidance brings unprecedented confidence and efficiency to various on-site scenarios.

The future of civil surveying and the role LRTK will play

Civil surveying is now at a major turning point. With the Ministry of Land, Infrastructure, Transport and Tourism promoting *ICT construction* and *i-Construction*, construction management that once relied on craftsmanship is rapidly shifting toward digitalization and automation. The fusion of GNSS, AR, 3D scanners, and cloud technologies is transforming the very nature of surveying.

In this context, LRTK’s role is substantial because anyone with a smartphone can behave like a surveyor. It brings what used to require costly equipment and specialized knowledge within reach, enabling each on-site worker to make data-driven decisions and take action. For example, you can instantly share “yesterday’s backfill volume” at a progress meeting or compare point cloud models across distant sites. Being able to digitally grasp the site’s real-time “now” leads to waste-free construction and precise decision-making.

As surveying equipment becomes smaller and more powerful and AI utilization advances, on-site DX will accelerate further. LRTK, as a pioneer, symbolizes this new era in civil surveying. In a future where not only surveying experts but also construction managers and individual tradespeople handle data, “easy-to-use and high-precision” tools like LRTK will be indispensable. Soon it may become commonplace to take out a smartphone on site and perform surveying, layout marking, and inspection. LRTK is expected to be a game changer that brings that future forward.

Conclusion: start simple surveying with LRTK

The world of civil surveying and layout marking is about to be transformed by smartphones and LRTK. Layout marking, which was important but laborious, can now be done quickly and precisely with a smartphone in hand. The impact of smartphone surveying is already appearing on sites in terms of labor savings, efficiency, and quality assurance through improved accuracy.

If you are worried whether this new technology will actually work on site, consider trying simple surveying with LRTK first. Once you use it, you will be surprised how points on a drawing appear seamlessly at the real location. After experiencing it once, you may find it hard to return to traditional layout marking. Intuitive LRTK will become a reliable partner for busy sites.

As a key to improving productivity and quality at construction sites, and as a future standard technology, try incorporating smartphone surveying with LRTK on your sites. The new era of civil surveying is already in your hands.