3D Surveying Without Expert Knowledge: Starting Construction DX with LRTK

The construction industry is paying close attention to DX (digital transformation) driven by 3D surveying. Among the construction DX efforts that leverage ICT and AI, 3D surveying—which accurately digitizes site conditions—is a fundamental and important technology. Whereas three-dimensional measurement traditionally required expensive surveying equipment and specialized expertise, recent technological advances are making it possible for anyone to use these tools without expert knowledge.

This article explains the basics and benefits of 3D surveying, examines the challenges of conventional methods, and considers its role in construction DX. It also introduces “LRTK” as an example of a new technology that can be implemented with no expert knowledge required, and describes the transformation it brings to the field.

What is 3D surveying?

3D surveying (3D measurement) is a method of measuring the position and shape of objects or terrain as three-dimensional coordinate data (length, width, height). A key feature is that it captures three-dimensional shapes that conventional planar (2D) surveying could not. Specifically, sensors such as laser scanners and cameras are used to obtain point cloud data (a collection of many coordinate points) from the surface of the object, and 3D models of terrain or structures are generated from that point cloud. Methods of 3D surveying include aerial photogrammetry using drones, ground-based 3D laser scanner measurements, and, more recently, scans using LiDAR sensors built into smartphones. Because all of these approaches acquire the shape of the target as digital 3D data, they are highly useful for civil engineering works and infrastructure maintenance and management.

Benefits of 3D surveying

3D surveying offers many benefits not available in traditional manual-centered surveying. First, it enables efficient measurement of large areas in a short time. Using drones or laser scanners, large sites can be scanned in a short time to collect massive amounts of point cloud data, drastically shortening tasks that used to take days with planar surveying. In fact, there are reports where surveying that used to take two days was completed in half a day using drone surveying:contentReference[oaicite:0]{index=0}. Second, it provides high-precision, comprehensive data. Because point cloud data records the entire object, there are fewer oversights compared to measuring individual points by hand, and it can detect differences down to the millimeter:contentReference[oaicite:1]{index=1}. For example, measurements of structures inside deep foundation pits—which were difficult to measure conventionally—have been reported to be safely and accurately performed using point cloud measurement. Third, safety improvements are notable.

Fourth, there are cost reduction effects from avoiding rework. High-precision measurement allows construction errors to be detected early and prevents rework, resulting in shorter project schedules and reduced unnecessary costs.

Even in dangerous or inaccessible locations, remote 3D surveying eliminates the need for direct work, improving worker safety. The acquired data can be shared in the cloud as digital records, allowing all stakeholders to view the same 3D information and facilitating smooth information sharing between the site and the office.

Major use cases for 3D surveying:

• Earthwork management: Volume calculations for cut and fill, and estimation of soil transport quantities

• As-built inspection: Comparing point cloud data with design models to determine whether they meet required tolerances

• Construction progress management: Periodically scanning sites to record construction progress in 3D

• Infrastructure inspection: Using point clouds to capture displacements and damage of bridges, tunnels, etc., and analyzing long-term changes

• Disaster investigation: Rapidly grasping damage by aerial imaging and scanning immediately after a disaster

Challenges of conventional surveying and the barrier of specialized knowledge

Traditional surveying methods had several challenges, which contributed to the perception that “you need specialist knowledge to handle it.” The main issues are listed below.

• Time and labor burden: Manual surveying requires measuring and recording each point with a tape measure or total station, and measuring wide areas demanded enormous time and manpower. On sites with labor shortages, it was sometimes impossible to secure enough measurement points, reducing surveying frequency.

• Measurement errors and accuracy limits: Manual methods are always vulnerable to human error, and ensuring accuracy relied heavily on experience, with inherent limits. The data obtained was also limited, and because structures were captured only as discrete points, small deviations could be overlooked.

• Inefficient data management: Measurement results were recorded on paper drawings and tables, and managed by cross-referencing photo logs, making administration cumbersome. Digital data sharing did not progress, and finding needed information later was not easy.

Thus, traditional labor-intensive surveying suffered from being “time-consuming,” “incomplete,” and “underutilized,” and fundamentally improving these issues became necessary in the modern era that demands sophistication and efficiency. Historically, achieving millimeter-level high-precision positioning on site required specialized equipment and skilled technicians, and the equipment itself cost several million yen or more:contentReference[oaicite:2]{index=2}. Such high hurdles made 3D surveying seem like “the work of experts,” raising the barrier to widespread use.

Additionally, 3D surveying using drones or laser scanners required control point measurements (known reference points) to align the acquired data to an accurate coordinate system, as well as sophisticated post-processing to correct point cloud distortions:contentReference[oaicite:3]{index=3}. These tasks demanded specialized knowledge and substantial time, further increasing the barriers to 3D surveying.

3D surveying propelled by construction DX

To solve the challenges above, innovative initiatives using surveying DX (digital transformation of surveying) and smart construction are progressing in the construction industry. Under initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism’s *i-Construction* (measures to improve productivity through ICT use at sites) and infrastructure DX promotion policies, the move to centralize the entire construction production process—from survey and measurement to design, construction, inspection, and maintenance—using 3D data is accelerating:contentReference[oaicite:4]{index=4}. Specifically, the use of point cloud data obtained by drone aerial photography or ground laser scanners and BIM/CIM models created during design for site management is becoming widespread, leading to dramatic improvements in construction accuracy and operational efficiency:contentReference[oaicite:5]{index=5}. As mentioned earlier, examples include significant time reductions from drone surveying and productivity improvements of about 30% through automatic control of construction machinery and IoT-based real-time visualization:contentReference[oaicite:6]{index=6}. By introducing 3D surveying technology, it has become possible to measure large areas non-contact and at high speed, and software can automatically analyze the detailed data for quality checks and quantity calculations. This makes it feasible to detect minute displacements that were difficult to observe with manual surveying, perform immediate pass/fail judgments, and rapidly create as-built documentation. Indeed, surveying DX is fundamentally changing construction management.

Emergence of technologies that remove the need for specialized knowledge

Recent technologies have made “3D surveying without expert knowledge” increasingly realistic. A representative example is high-precision surveying devices compatible with smartphones. For instance, a combination of a small GNSS receiver that attaches to a smartphone and a dedicated app enables centimeter-level positioning easily by anyone:contentReference[oaicite:7]{index=7}. Traditionally, centimeter-level RTK-GNSS surveying required expensive equipment and skilled operators, but with just a smartphone and a palm-sized receiver, positioning can be started with the press of a button and without complex settings:contentReference[oaicite:8]{index=8}:contentReference[oaicite:9]{index=9}. The acquired positioning data is automatically saved and shared in the cloud, making it possible to share information between the field and the office in real time. Some recent products support Japan’s satellite positioning augmentation service “Michibiki” CLAS signals, allowing devices to receive correction information directly from satellites and maintain accuracy even in mountainous or communication-outage situations. With these advanced technologies, the era has arrived in which site personnel can perform 3D surveying themselves without surveying expertise or advanced equipment operation.

Intuitive 3D scanning technologies that leverage smartphone cameras and sensors are also evolving. For example, there are solutions that allow virtually anyone to obtain point clouds simply by walking while holding a smartphone:contentReference[oaicite:10]{index=10}. By pointing the camera and moving through the site, high-precision point cloud data with position coordinates is automatically generated, and distance, area, and volume measurements are completed in the cloud:contentReference[oaicite:11]{index=11}. The previously cumbersome installation of control points is unnecessary, and the acquired point clouds can be used in formats that comply with the standards set by the Ministry of Land, Infrastructure, Transport and Tourism, providing quality sufficient for formal as-built documentation:contentReference[oaicite:12]{index=12}. Such “walk-and-scan” technologies enable site staff to intuitively conduct 3D surveying.

Moreover, a variety of 3D surveying devices tailored to field applications have emerged. For example, some high-precision GNSS devices include a 360° camera and allow hands-free positioning by mounting thin antennas on helmets or vests:contentReference[oaicite:13]{index=13}. Because workers’ exact positions can be known in real time, such systems can trigger alerts if a worker accidentally enters a restricted area, contributing to safety management:contentReference[oaicite:14]{index=14}. These new technologies not only increase surveying efficiency but also enhance on-site safety.

Furthermore, the use of AR (augmented reality) to overlay acquired 3D data on the real world is advancing. By displaying 3D design models on a smartphone or tablet and overlaying them on actual site footage, it becomes possible to intuitively confirm differences between design drawings and the current state. For example, displaying the positions of previously scanned underground utilities in AR makes it easy for anyone to avoid them during excavation:contentReference[oaicite:15]{index=15}. AR functions are also useful for sharing the completed image between clients and contractors, reducing communication loss.

Starting construction DX with LRTK

:contentReference[oaicite:16]{index=16} *A small LRTK positioning device (LRTK Phone 4C) attached to an iPhone. Palm-sized, it can turn a smartphone into a high-precision surveying instrument.*

Among the many emerging technologies, LRTK was created specifically for practical use on construction sites. LRTK is a solution consisting of a smartphone-mounted RTK-GNSS receiver device and a cloud service developed by a startup originating from Tokyo Institute of Technology, enabling a smartphone to become a “surveying instrument for each person”:contentReference[oaicite:17]{index=17}:contentReference[oaicite:18]{index=18}. By attaching a compact receiver weighing about 125 g to an iPhone or iPad and launching the dedicated app, real-time positioning begins without complex setup, receiving correction information from base stations to calculate the device’s position on the smartphone to centimeter-level accuracy:contentReference[oaicite:19]{index=19}. LRTK has transformed centimeter-level positioning—which previously required total stations or expensive GNSS equipment—into a task anyone can perform:contentReference[oaicite:20]{index=20}. The ease with which site supervisors and construction managers can carry out surveying with a smartphone in hand truly makes it a “DX tool anyone on site can use.”

The impact of introducing LRTK is significant. For example, when a photo is taken with a smartphone, latitude, longitude, altitude, and camera orientation are automatically recorded, allowing a geotagged photo log to be created with a single tap:contentReference[oaicite:21]{index=21}. In earthworks, volumes for fill and excavation can be calculated instantly from acquired point cloud data, and deviations from the design model can be color-coded to make as-built discrepancies immediately visible. Because the resulting 3D data is managed and shared in the cloud, information measured on site can be shared instantly with the office or clients, enabling rapid decision-making. Even in mountainous areas without connectivity, models supporting CLAS satellite signals can perform standalone positioning, making it possible to conduct high-precision surveys and share information in disaster-stricken areas as long as an LRTK terminal is available:contentReference[oaicite:22]{index=22}. From a cost perspective, LRTK is far more affordable than traditional equipment, making one-device-per-person deployment realistic:contentReference[oaicite:23]{index=23}. Instead of expensive equipment being used only by specialized departments, an era is dawning where site workers can pull an LRTK from their pocket and perform surveying whenever needed.

In practice, high-precision positioning technologies including LRTK are being adopted across a wide range of sectors, such as construction consultants, surveying companies, construction firms, infrastructure-related companies, and local governments, and their compact, high-precision, and affordable characteristics are accelerating adoption:contentReference[oaicite:24]{index=24}. These innovative solutions are expected to significantly contribute to the advancement of i-Construction and DX in the construction sector promoted by the Ministry of Land, Infrastructure, Transport and Tourism:contentReference[oaicite:25]{index=25}.

As described above, 3D surveying is no longer the exclusive domain of surveyors. Riding the wave of DX, 3D surveying without specialist knowledge is dramatically improving on-site productivity and quality. It can also help address urgent industry issues such as the 2024 problem (limits on overtime hours) and chronic labor shortages by streamlining surveying with smart technologies.

Of course, introducing digital technologies also requires human resource development and a review of traditional workflows. However, if site technicians become proficient with these ICT tools and fully leverage the data, the benefits of DX will be maximized. If you are considering adopting 3D surveying, you might start by evaluating solutions like LRTK that are easy to implement. By taking the first step to start construction DX with LRTK, you can bring the power of digital surveying to the field and elevate construction efficiency and accuracy to the next level.

Harness advanced technologies and let 3D surveying spark a wave of digital transformation on your sites. The sooner you act, the greater the gains and competitive advantages are likely to be.

The digital wave is already upon us. Embrace technology on-site proactively so you don’t fall behind.