High-Precision GPS Positioning Is Changing Construction Sites! A New Era of Precision Construction

GPS (Global Positioning System) was originally developed in the United States for military use, but since being opened to the public it has been adopted across many parts of society because of its convenience. Thanks to GPS, car navigation systems and smartphone map apps can easily show our current location.

However, positioning technology on construction sites is now at a major turning point. Conventional GPS-based position measurements, while convenient, have had limitations in accuracy that made on-site use challenging. In recent years, however, centimeter-level high-precision GPS positioning—exemplified by RTK—has emerged, and this is beginning to dramatically change how construction work is carried out and managed. A true “new era of precision construction” is arriving.

This article starts by explaining the limitations of conventional GPS use, then describes how high-precision GPS positioning works and its power, and outlines the concrete changes it brings to construction sites. It also touches on the digitalization trend on sites through smartphone integration and cloud usage, and finally introduces the latest solution, LRTK, along with its features and benefits of adoption. Let’s explore the future of construction sites made possible by high-precision positioning technology.

Conventional GPS Use and Its Limitations

When measuring positions on construction or survey sites, the well-known GPS has long been used. The GPS used in everyday smartphone map apps and car navigation systems can determine positions with an accuracy of several meters (a few ft). This accuracy is sufficient for daily use, but it does not reach the level required for “precision construction” in building and civil engineering. For example, even an error of a few centimeters (a few in) in locating a building’s foundation or surveying the centerline of a road can cause serious problems.

Therefore, on traditional sites, where high-precision positioning was required, teams did not rely solely on GPS but combined it with surveying instruments such as total stations (electro-optical distance meters) and levels. Position information obtained from conventional GPS receivers remained uncertain due to satellite signal errors and atmospheric effects. In addition, near buildings or in mountainous areas, signals from satellites can be blocked or reflected, further degrading accuracy. In this way, ordinary GPS usage had limitations in both accuracy and environmental conditions, making precise positioning on construction sites challenging.

It should be noted that high-precision GPS receivers themselves have existed for some time, but their antennas and equipment were bulky, expensive, and required specialized knowledge to operate. As a result, except for some large-scale projects, they were rarely used routinely on general construction sites.

What Is High-Precision GPS Positioning (RTK, Centimeter-Level)?

In recent years, “high-precision GPS positioning” has attracted attention as a technology to solve this problem. As the name suggests, high-precision GPS positioning is a collective term for positioning technologies that achieve centimeter-level accuracy, with RTK (Real-Time Kinematic) being a representative method. RTK uses two receivers—a base station and a rover—and performs real-time error correction based on reception data at the base station, improving positioning accuracy to within a few centimeters. This can reduce errors that were around 5–10 m (16.4–32.8 ft) with regular GPS down to just a few cm (a few in). In other words, RTK is an advanced form of “differential positioning” that corrects GPS errors, and by using the carrier-phase of the radio wave—a very fine signal component—it achieves orders-of-magnitude better accuracy than conventional DGPS (meter- to decimeter-level).

To achieve high-precision positioning, it is also effective to receive satellite signals on multiple frequency bands and to use multiple satellite positioning systems (not only GPS but also GLONASS, Galileo, and QZSS/Michibiki). For RTK, a “network RTK” approach is becoming widespread in the field, where only the rover is set up on site and correction information is obtained from existing electronic reference point networks or Internet-based services. This makes it possible to achieve centimeter accuracy without preparing your own base station. In Japan, high-precision positioning services using the Quasi-Zenith Satellite System “Michibiki” have also been developed, allowing positioning accuracy to be improved by satellite augmentation signals even in mountainous areas with poor communication environments.

These technologies are making centimeter-level high-precision positioning more accessible. Beyond construction, applications of high-precision positioning are expanding to areas such as autonomous agricultural machinery guidance and position control for infrastructure-inspection drones, and the technology’s reliability improves year by year. Precision position-setting that once required specialized surveyors and expensive equipment is becoming easier to perform.

The Importance of Precision Construction on Site

On construction sites, structures must be built in the locations and dimensions specified by the design drawings. For example, if the positions of building columns or bridge piers are off by even a few centimeters (a few in), structural distortions may occur after construction or connections with other members may be compromised. In civil engineering, if the alignment of roads or tunnels deviates from the plan, it can affect safety and durability. In tunnel construction in particular, a slight error in excavation direction can lead to misalignment when tunneling from both ends, and positioning accuracy can determine the success of the project. In this way, “precision construction” is extremely important for quality assurance and safety management.

In addition, digitalization in the construction industry has been progressing, and construction planning using 3D models such as BIM/CIM is becoming more common. To accurately reproduce these digital design data on site, positional discrepancies must be minimized. Without the ability to measure positions precisely, even carefully planned high-precision digital designs cannot be reliably realized in the field. In other words, high-precision positioning technology is a foundational technology that supports digital construction and construction DX (digital transformation). High-precision positioning is also a core element in ICT utilization on construction sites promoted by the Ministry of Land, Infrastructure, Transport and Tourism’s “i-Construction” initiative.

Furthermore, precision positioning contributes to construction efficiency. If accurate position-setting can be done correctly the first time, rework and retries are reduced, leading to shorter schedules and cost savings. Conversely, surveying errors or position deviations that require corrections in later stages cause extra work and costs. Introducing high-precision positioning technology that can be used on site is therefore important to realize precision construction.

Changes on Site Brought by High-Precision GPS (Layout, As-Built, Point Clouds, etc.)

The introduction of high-precision GPS has brought various changes to concrete work processes on construction sites. Major examples where significant effects are beginning to appear include the following areas:

• Improved efficiency of layout work: Layout tasks for buildings and structures traditionally required survey teams to mark lines on site with plumb lines or tape measures based on drawings, which was time-consuming. With high-precision GPS, you can instantly identify points exactly as defined in the design coordinates, dramatically speeding up the marking of control points. Manual measurement errors are also reduced, which decreases rework in later stages and improves quality.

• Faster and higher-precision as-built surveys: High-precision GPS is also powerful for “as-built surveys” that confirm the shape of the ground after embankment or excavation, or structures after concrete placement. Previously, it was necessary to measure each designated point one by one, but with equipment equipped with a high-precision GPS receiver you can walk the site and quickly acquire many points’ elevation and position data in a short time. The obtained data are recorded digitally, making volume calculations and as-built documentation easy.

• 3D point cloud data for site records: Combined with drone aerial photography or terrestrial laser scanners, high-precision GPS can produce 3D point cloud data with accurate georeferencing. In particular, with drone surveying, equipping the aircraft with a high-precision GNSS allows accurate reconstruction of the ground surface from many aerial photos, significantly reducing the need for control point surveys. Detailed topographic surveys that were previously outsourced to specialists can now be performed quickly by site teams using relatively simple GPS-linked equipment. By analyzing the acquired point cloud data, you can visualize pre- and post-construction terrain changes and display subtle as-built differences in color, enabling advanced digital management.

• Automatic control of construction machinery (machine guidance): Increasingly, construction machines such as bulldozers and excavators are fitted with high-precision GPS to automatically adjust blade or bucket heights during operation. Even without relying on operator experience, machines can grade soil to the designed slope and elevation based on GPS position data, improving finish accuracy and reducing rework. This contributes to reducing operator burden and labor requirements. Such ICT-driven construction machinery is only possible with high-precision GPS.

Smartphone Integration and Cloud Support for Site Digitalization

To make the most of high-precision GPS positioning performance, usability and data utilization mechanisms are also important. The keys are smartphone integration and cloud support. If a familiar smartphone can be used as a positioning device on site instead of specialized, difficult surveying instruments, various personnel—not just technical specialists—can handle position information. Measurements can be taken while viewing maps or drawings in a smartphone app, and results can be immediately checked as numbers or graphs. Intuitive operation makes it easy for staff without formal training to use, which raises overall IT literacy on site. With a shortage of experienced survey technicians, spreading tools that anyone can use helps address manpower shortages and skills transfer issues.

Combining a smartphone camera with high-precision positional information also enables AR (augmented reality) construction support. For example, through the smartphone screen you can overlay design lines or 3D models of the finished structure on the real scene. This makes it easy to visually identify excavation locations or the positions of buried objects and to share the completed image on site. Because high-precision GPS automatically handles complex alignment, anyone can use high-accuracy AR displays.

Moreover, with cloud support, survey data, photos, and notes collected on site are instantly saved and shared to the cloud. There is no need to return to the office to copy data via USB or bring back paper drawings with handwritten notes. Through the network, the latest site information can be shared in real time with the office and other stakeholders, enabling rapid progress reporting and quick response when problems occur. Accumulating data in the cloud also makes it easy to reference and analyze past construction records and measurements. Digital data management reduces human errors such as misreading handwritten notes or transcription mistakes, improving information reliability. Smartphone and cloud integration thus advance full site digitalization and play an important role in construction DX.

Introduction to LRTK and Benefits of Adoption

Finally, the LRTK introduced here is a state-of-the-art, simplified surveying solution that integrates the high-precision GPS positioning and smartphone/cloud connectivity described above into an all-in-one package. It consists of a compact receiver small enough to fit in your pocket and a smartphone app, allowing anyone to easily perform centimeter-precision positioning. The major feature of LRTK is that RTK positioning, which formerly required specialized institutions and expensive equipment, can be handled with just a smartphone in hand at the site.

The LRTK receiver weighs only 165 grams and includes a built-in battery; it connects wirelessly to a smartphone. On site, you simply mount the smartphone and receiver on a dedicated pole (monopod) and survey, enabling efficient one-person operation. Button operations are simple, so even beginners can start high-precision positioning without hesitation. Positioning data are tagged in real time with latitude, longitude, and elevation information, and the app can convert and display them as map coordinates or reference point coordinates.

In terms of accuracy, LRTK achieves centimeter-level precision comparable to first-class surveying GNSS equipment. It delivers horizontal positioning accuracy of approximately 1–2 cm (0.4–0.8 in) and vertical accuracy within a few centimeters (a few in), so height measurements that are difficult with normal GPS are not a problem. With the use of satellite augmentation signals, accuracy can be maintained even in mountainous or out-of-coverage areas, and municipalities have begun using LRTK for disaster situational awareness. In private construction sites as well, site supervisors and construction managers are increasingly carrying LRTK to perform necessary surveys on the spot.

LRTK also offers rich software features.

For example, the LRTK app can provide functions such as:

• AR-based site support (projection display of design data, etc.)

• 3D point cloud scanning (high-density point clouds from smartphone sensors and photos)

• Pile-driving coordinate navigation (guidance to specified coordinates)

• Geotagged site photo capture (photos with position and orientation)

• Automatic cloud sync and data sharing

With this single solution, surveying, design verification, and as-built management can be handled seamlessly, making it highly valuable as a site DX tool.

The benefits of adoption are also clear. By using LRTK, companies can reduce outsourcing surveying costs while obtaining data quickly in-house. Site staff can perform surveys when needed, reducing waiting times and smoothing construction scheduling. Furthermore, by enabling construction that does not rely on paper drawings or string-lines, LRTK shifts work away from intuition-based practices by experienced personnel toward reproducible, data-driven construction. The result is both improved quality control and cost reductions through labor savings, making it an attractive investment for decision-makers. Initial adoption costs are also lower compared to conventional surveying equipment, making LRTK accessible from a cost perspective.

High-precision GPS positioning technology is becoming an everyday tool on site rather than something special. The fusion of precise positioning and digital technology will accelerate further, and sites that can adapt to these changes will lead the industry. By leveraging solutions like LRTK, you can be at the forefront of the new era of precision construction, achieving improved productivity and quality assurance ahead of competitors.