What is AR Pile-Driving Guidance? Achieving Precise Layout with High-Accuracy Positioning

Table of Contents

• Challenges of on-site pile-driving work

• What is AR pile-driving guidance

• How to use an AR pile-driving guidance app

• Benefits of AR guidance

• Use for pile-center confirmation

• Efficiency in pre-construction preparation

• Why site supervisors are convinced

• Simple surveying with LRTK

• Frequently asked questions

Challenges of on-site pile-driving work

On civil engineering and construction sites, pile-driving work to install piles that form the foundation of structures and layout work to mark the positions of buildings and equipment are indispensable. In these processes, you must identify on-site positions that match the numerical coordinates shown on drawings down to the last detail; this is a critically important process that determines construction accuracy and safety. However, determining pile-driving positions by traditional methods is by no means easy.

Typically, aligning positions for pile-driving and layout requires advanced surveying techniques and considerable effort. A team including a surveyor uses a total station (optical surveying instrument) and measuring tapes to measure distances and angles from reference points, marking the ground with stakes or chalk. Even determining a single pile position requires multiple measurement steps, and on a large site with dozens of piles, layout alone can take an entire day or more. Moreover, as long as humans perform surveying and marking by hand, there is an inherent risk of human error. Even a small misread or recording mistake can shift a pile position and cause rework or construction errors in later stages.

Additionally, issues of efficiency and safety cannot be ignored. For example, when establishing references on steep slopes or muddy ground, poor footing can expose workers to danger and hinder progress. When survey staff must mark pile positions in areas where heavy machinery is operating, the risk of accidents due to proximity between machines and people increases. In some places it can even be physically difficult to drive a stake, forcing compromises by marking approximate positions. In short, traditional pile-layout work has required large amounts of manpower and time while facing challenges in accuracy control and safety assurance. To solve these on-site problems, a new “pile-driving guidance” solution that uses AR technology and high-accuracy positioning has emerged in recent years.

What is AR pile-driving guidance

“AR pile-driving guidance” is a system that uses AR (augmented reality) technology to guide users to specified coordinates. It overlays markers and navigation information for target points (such as pile-driving positions) onto the camera view of a smartphone or tablet. Imagine the feature in some map apps that overlays an arrow on the camera view to indicate the direction to walk; AR pile-driving guidance applies that idea to guiding users to pile positions on a construction site. If you preload the app with the design coordinate data from the drawings, the AR overlay can visualize instructions like “install a pile here” directly in the real world.

The key to realizing this system is linking AR with positioning technology that can determine the smartphone’s current location with centimeter-level accuracy (half-inch accuracy). The typical GPS built into smartphones has an error on the order of meters, which is insufficient for accurately indicating pile positions on construction sites. What is used instead is high-accuracy GNSS positioning such as the RTK (Real Time Kinematic) method, which dramatically improves position accuracy by using correction information from base stations or satellites. In Japan, services such as the QZSS-provided centimeter-level positioning augmentation service (CLAS) are making it increasingly possible to use RTK positioning relatively easily without a dedicated base station. By attaching an external high-precision GNSS receiver to a smartphone and enabling RTK, you can measure your own position with accuracy comparable to traditional optical surveying instruments.

Combining high-accuracy current position information with AR display has evolved pile-driving guidance into essentially a construction-site navigation system. The smartphone screen displays the real scene with real-time navigation showing direction and distance to the target point. For example, if you select the target pile position data, guidance such as “Target: 5 cm (2.0 in) east” and “10 cm (3.9 in) north” may appear on the screen. The worker can follow those instructions and take just a few steps to stand exactly at the design position.

When the target point is reached, a virtual pile (an AR marker) appears on the ground in the camera view, intuitively confirming “this is the pile tip position.” Even inexperienced staff can identify the correct point without hesitation by following the arrows and markers visible through the smartphone.

How to use an AR pile-driving guidance app

• Prepare design data: Preload the app with the design coordinate data for the piles required by the project. Upload the target pile position information from coordinate lists or CAD drawings to the cloud so you can call them up quickly on site.

• Set up the device and positioning: On site, attach a high-precision GNSS receiver (RTK-capable device) to the smartphone and start the dedicated pile-driving guidance app. When the GNSS receiver acquires satellite signals and correction information and centimeter-level positioning accuracy (half-inch accuracy) is achieved, you are ready. Initialization of positioning takes several tens of seconds, and guidance can begin immediately.

• Select the target: Choose the pile number or point you want to guide to in the app. Tap the desired point from the pre-registered coordinate data, and that position becomes the navigation target.

• Start navigation: Direction and distance to the target are displayed in real time on the screen, and guidance begins. If the target is far, a large arrow appears in the center of the screen to indicate the direction; as you get closer it switches to fine distance guidance like “remaining: ○ cm.” By following the instructions you can approach the correct position without complicated drawing interpretation.

• Confirm position: When you reach the target, a virtual pile (AR marker) appears on the real-world view of the smartphone screen, shown as if firmly standing on the ground. If the AR marker and the real ground align without offset, that is the pile center position according to the design. The worker can confidently mark the point or signal for positioning while confirming on the screen.

• Execute pile-driving: Once the accurate position is confirmed, mark the point and signal the pile-driving machine operator to install the pile. Even on large sites, the AR marker helps prevent losing sight of the target and allows accurate pile installation at the intended point.

• Save construction records: After pile-driving is complete, take and save photos with the smartphone camera on the spot. The photos are automatically linked with the measured coordinates, allowing you to later review in the cloud “how many centimeters each pile was installed from the design position.” Keeping digital construction records on site makes it easy to prepare reporting materials and quality verification for the client.

Benefits of AR guidance

• Improved accuracy: Combining centimeter-level positioning accuracy (half-inch accuracy) from high-precision GNSS with visual AR guidance minimizes deviation from design coordinates. Precisely identifying pile center positions that was difficult with only measuring tapes and manual layout becomes easy, providing consistently stable accuracy without relying on the intuition of experienced workers.

• Labor savings and increased efficiency: Layout work that previously required a surveying team and hours of work can be completed quickly by one person with a smartphone. Even on sites with many piles, layout work that used to take all day can be dramatically accelerated, reducing personnel needs and shortening schedules. Reducing rework and reinstallation can lead to shorter construction periods and cost savings.

• Improved safety: AR guidance reduces the need for people to perform surveying and marking in dangerous locations. For example, you can confirm positions on steep slopes or unstable ground from a safe distance by displaying virtual markers. The risk of workers approaching operating heavy equipment is also reduced, contributing to accident prevention. AR displays also help you see target points in nighttime or foggy conditions, making layout possible under poor visibility.

• Digital records and quality assurance: Installation positions and deviations for each pile can be recorded and shared as digital data, making post-construction quality checks and reporting much easier. Managing coordinate data centrally in the cloud allows objective verification later of which piles deviated and by how much, streamlining evidence submission to clients and regulatory authorities and increasing confidence in construction quality.

• Mobility and ease of introduction: While specialized surveying equipment can seem bulky and expensive, AR guidance that combines a smartphone with a small GNSS receiver is highly portable and relatively low in initial investment. You don’t need to carry heavy tripods or long cables; you can operate one-handed while moving around the site. The convenience of quickly taking out the device and immediately performing positioning and guidance offers great advantage on busy construction sites. The smartphone app interface is intuitive, so workers without specialized surveying knowledge can operate it, minimizing training costs.

Use for pile-center confirmation

Pile-driving guidance apps are powerful not only for pre-installation layout but also for post-installation pile-center confirmation. Traditionally, after pile-driving you would re-survey to confirm that each pile center matches the design, which required time and effort. Using AR coordinate navigation, you can efficiently perform that confirmation simultaneously with construction.

Specifically, after driving the pile, point the smartphone camera at the pile head and check for displacement relative to the AR marker. If the virtual pile marker aligns exactly with the real pile, it proves the pile was installed at the design position. If there is a slight displacement, the app will display a numeric value such as “2 cm (0.8 in) east,” allowing you to immediately grasp the error amount. In this way you can instantly verify the positional accuracy of all piles and take corrective measures as needed.

Furthermore, because installation position data and photos for each pile are stored in the cloud as mentioned above, you don’t need to remeasure after returning to the office. Later you can view a list showing, for example, “Pile No. X was 3 cm (1.2 in) north of the design,” facilitating the creation of as-built drawings and quality reports. Digitizing pile-center confirmation greatly reduces the burden on site supervisors and quality control personnel.

Efficiency in pre-construction preparation

AR pile-driving guidance apps also bring significant efficiency to pre-construction preparation. Traditionally, before starting work a surveying team would enter the site to check reference points and perform reconnaissance and preliminary marking of pile positions. This required long on-site work and multiple personnel, but AR coordinate navigation can simplify that process.

For example, site supervisors or responsible engineers can walk the site with a smartphone and sequentially check planned pile positions in the app. If all pile coordinates are preloaded in the app, you can circulate the points in order by following the on-screen navigation. Even on large sites you can view all pile positions in a short time, make provisional marks at key points, and check for obstacles—all by one person.

Also, because design data is managed in the cloud, uploading the latest drawing coordinates from the office before visiting the site ensures automatic synchronization of accurate position information on site. This prevents preparation mistakes due to overlooking drawing details or transcription errors. Conducting thorough digital position checks before construction begins prevents trouble such as “positions do not match and work must be redone” once work starts. As a result, the pre-construction process runs more smoothly and the overall schedule gains flexibility.

Why site supervisors are convinced

The benefits described above are strong selling points for site supervisors who manage construction on site. First, supervisors can objectively guarantee construction quality through improved pile position accuracy and digital record management. Being able to grasp in real time whether all piles are positioned according to the design and to detect and correct deviations immediately greatly reduces the risk of having to address defects later. Quality inspection results backed by numerical data and photos make explanations to regulatory authorities and clients clear and persuasive.

Moreover, labor savings and improved safety make site management smoother. Completing layout work efficiently with fewer people allows supervisors to allocate resources to other important tasks. Reducing hazardous tasks lowers the risk of occupational accidents and lessens the overall safety management burden. Because inexperienced staff can perform accurate work by following the AR navigation, supervisors need not worry about variability in workmanship. The need for supervisors to continually check measurements or give instructions at every step is reduced, improving team coordination on site.

Additionally, using AR + high-accuracy positioning technology aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s promotion of “i-Construction” (efforts to improve site productivity and digital transformation). Sites that proactively adopt digital tools receive high evaluations from clients, and supervisors can confidently say “we manage accuracy with the latest technology.” A convincing and trusted pile-driving guidance app will boost the confidence and motivation of the entire construction team.

Simple surveying with LRTK

One solution that has emerged to easily realize RTK + AR pile-driving guidance is LRTK. LRTK is an all-in-one site DX tool comprising a small RTK-GNSS receiver that can be attached to a smartphone, a dedicated app, and cloud services, allowing a smartphone itself to function as a high-precision surveying instrument. By attaching a pocket-sized receiver to the smartphone you can obtain centimeter-level current position (half-inch accuracy) in real time, and immediately perform AR display on the basis of the acquired coordinate data. Previously separated processes—surveying, layout, record-keeping, and as-built management—can be completed with a single smartphone when using LRTK.

No difficult operations or advanced knowledge are required; even people without surveying experience can derive accurate pile positions just by following the smartphone screen prompts. It is truly an innovative tool that enables “anyone” to perform pile-position layout. Using simple surveying with LRTK dramatically improves efficiency and accuracy control for tasks that previously required much time and manpower. As a strong ally that powerfully supports on-site digitalization, LRTK will undoubtedly attract increasing attention going forward.

Frequently asked questions

Q. What equipment and environment are required to use AR coordinate navigation? A. Basically, you need a smartphone (or tablet) with the AR guidance app installed and a GNSS receiver capable of centimeter-level positioning (RTK-capable, e.g., an LRTK device). In addition, you need a communication environment (internet connection) to obtain correction information for high-accuracy positioning and an outdoor environment with sufficient satellite visibility. Having these in place allows smooth use of AR coordinate navigation on site.

Q. Can accurate pile layout be done with only the smartphone’s built-in GPS? A. Unfortunately, the GPS in common smartphones (standalone positioning) has an error of several meters, so it is unsuitable for precise pile layout. To achieve the centimeter-level accuracy introduced in this article, RTK-GNSS augmentation is essential. In other words, using dedicated high-precision GNSS devices or correction services (network RTK base station information or satellite correction signals) is necessary for AR guidance to demonstrate its true value. Solutions like LRTK enable high-accuracy positioning even with a smartphone, so you can be confident.

Q. Can people without surveying experience use it proficiently? A. Yes. AR pile-driving guidance apps feature intuitive user interfaces designed to be easy to use even for those without specialized surveying knowledge. You simply follow the on-screen guidance to move and confirm; no difficult calculations or advanced settings are required. Once you learn the basic operations, even non-experts can utilize the system effectively on site. In fact, there are cases where tasks that previously required a surveyor are now being handled by young staff with no problem.

Q. Will bad weather or poor radio conditions interfere with work? A. Generally it can be used outdoors regardless of weather, but GNSS positioning requires an open sky environment. Extreme weather such as heavy rain or snow does not in itself have a large effect on positioning accuracy (it may take longer to acquire satellites), but environments surrounded by buildings, tunnels, or indoors block satellite signals and prevent high-accuracy positioning. Also, if you use network-based RTK corrections you need to be within a communication area. In sites like mountainous regions with unstable communications, offline augmentation methods such as QZSS (CLAS) may be used. Note that AR markers themselves can be displayed at night, but because the camera must capture the real scene, some on-site lighting is necessary.

Q. Can this technology be used for purposes other than pile-driving? A. Yes—the range of applications extends beyond pile-driving. In construction and civil engineering, AR coordinate navigation can be applied to foundation layout, marking positions for equipment installation, checking as-built measurements, and more. You can also visualize the positions of buried pipes and cables with AR to improve safety during excavation, or overlay 3D design models onto live site video to intuitively share construction images. In short, AR visual guidance is effective in any situation where showing “accurate positions” on site is necessary.