Table of Contents

• Challenges of on-site pile-driving work

• What AR coordinate navigation is

• How to use the AR pile-driving guidance app

• Benefits of AR guidance

• Use for confirming pile centers

• Efficiency in pre-construction preparation

• Why site supervisors are satisfied

• 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 indicate the positions of buildings and equipment on site are indispensable. These processes require pinpointing exact positions on site based on the coordinate values shown on drawings, and they are crucial for construction accuracy and safety. However, determining pile-driving positions using conventional methods is by no means easy.

Typically, aligning positions for pile-driving and layout required advanced surveying skills and considerable effort. A team including a surveyor would use a total station (optical surveying instrument) and tape measures to measure distances and angles from reference points and mark the ground with stake marks or chalk. Even finding a single pile position demanded multiple measurement steps, and on large sites where dozens of piles are installed, it was not uncommon for positioning alone to take a full day or more. Moreover, because people perform surveying and marking by hand, there is always a risk of human error. A small misreading or transcription mistake can shift a pile position and cause rework or construction defects later in the process.

Additionally, efficiency and safety issues cannot be overlooked. For example, when establishing reference points on steep slopes or muddy ground, poor footing can endanger workers and complicate the task. 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 locations, it may even be physically difficult to drive stake marks, forcing compromise by marking approximate positions. In short, traditional pile-positioning workflows required substantial manpower and time while posing challenges for precision control and safety. To solve these onsite problems, a new “pile-driving guidance” solution that leverages AR technology and high-precision positioning has emerged in recent years.

What AR coordinate navigation is

“AR coordinate navigation” 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 live camera view of a smartphone or tablet. Think of it like a map app that displays arrows on the camera view to guide your direction, applied to guiding pile-driving positions on construction sites. If you preload the design coordinate data from drawings into the app, the AR overlay can visualize instructions like “drive a pile here” directly in the real world.

A key to making this system work is linking it with positioning technology that can determine the smartphone’s current location with centimeter-level precision (cm level accuracy (half-inch accuracy)). Ordinary built-in smartphone GPS produces errors on the order of several meters (several ft), which is insufficient for accurately indicating pile positions on construction sites. What’s used instead is high-precision GNSS positioning such as RTK (Real Time Kinematic), which dramatically improves accuracy by using correction information from base stations or satellites. In Japan, services like the quasi-zenith satellite system Michibiki (QZSS) provide centimeter-class positioning augmentation services (CLAS), making RTK positioning increasingly accessible even without dedicated base stations. By attaching an external high-precision GNSS receiver to a smartphone and enabling RTK, you can measure your position with accuracy comparable to conventional optical surveying instruments.

Combining high-precision current position information with AR display has evolved pile-driving guidance into something like a car navigation system for construction sites. The real-world view on the smartphone screen shows the direction and distance to the target in real time. For example, when you select the desired pile position data, the screen can display guidance such as “5 cm (2.0 in) east to the target” or “10 cm (3.9 in) north,” allowing the worker to take a few steps and stand exactly at the design point. When the worker reaches the target, a virtual pile (AR marker) rises from the ground in the camera view, intuitively indicating “this is the pile tip position.” Even inexperienced staff can identify the correct point simply by following the arrows and markers visible through the phone.

How to use the AR pile-driving guidance app

Below is a general procedure for using AR coordinate navigation to determine pile-driving positions.

• Prepare design data: Preload the design coordinate data for the piles required by the project into the app. Upload the target pile position information from coordinate lists or CAD drawings to the cloud so it can be called up on site.

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

• Select the target: Choose the pile number or point you want to guide to within the app. Tap the desired point from the registered coordinate data to set it as the navigation target.

• Start navigation: The direction and distance to the target are displayed on the screen in real time, and guidance begins. If the target is far, a large arrow appears in the center of the screen showing the direction to move; as you approach, the display switches to fine distance guidance such as “remaining ○ cm.” By following the instructions, you can approach the correct position without complex drawing interpretation.

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

• Execute pile-driving: Once the exact position is confirmed, mark the point and signal the pile-driving machine operator to drive the pile. With AR markers visible across even large sites, you won’t lose sight of the intended point and can install piles at the targeted locations.

• 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 recorded coordinates, enabling later bulk confirmation in the cloud of “how many centimeters each pile was installed from the design position.” Having digital construction records on site makes it easy to prepare reports for clients or proof of quality.

Benefits of AR guidance

Using AR coordinate navigation for pile-driving guidance provides many advantages compared with conventional methods:

• Improved accuracy: Centimeter-level positioning (cm level accuracy (half-inch accuracy)) via high-precision GNSS and visual guidance through AR minimize deviations from design coordinates. Precisely identifying pile centers, which was difficult with only tape measures and manual layout, becomes easy, and stable accuracy can be attained without relying on a veteran’s intuition.

• Labor savings and efficiency gains: Positioning that used to require a survey team and hours of work can be completed quickly by one person with a smartphone. On sites with many piles, what once took a full day can be greatly accelerated, reducing personnel needs and shortening schedules. Fewer reworks and adjustments lead to faster completion and cost savings.

• Enhanced safety: AR guidance reduces the need for people to perform surveying and marking in hazardous locations. Even on steep slopes or unstable footing, you can verify positions from a safe distance using virtual markers. The risk of workers approaching operating heavy machinery decreases, contributing to accident prevention. AR displays also help identify target points under poor visibility, such as at night or in heavy fog.

• Digital records and quality assurance: Installation positions and errors for each pile can be recorded and shared digitally, making post-construction quality checks and reporting far easier. Centralized cloud management of coordinate data allows objective verification later of which piles deviated and by how much. Evidence submission to clients or inspection authorities becomes smoother, increasing confidence in construction quality.

• Mobility and ease of introduction: While specialized survey equipment can seem bulky and expensive, AR guidance using a smartphone combined with a compact GNSS receiver is highly portable and requires relatively low initial investment. There’s no need to carry heavy tripods or long cables, and you can operate one-handed while moving around the site. The convenience of quickly taking out the device and starting positioning and guidance is a major advantage for busy construction sites. Also, the intuitive smartphone app interface is easy for workers without specialized surveying knowledge to use, minimizing training costs.

Use for confirming pile centers

The pile-driving guidance app is effective not only for pre-driving positioning but also for post-driving “pile center confirmation.” Traditionally, after pile-driving was completed, separate surveying was required to check whether each pile center matched the design, which took time and effort. With AR coordinate navigation, you can efficiently perform that confirmation concurrently with construction.

Specifically, after driving a pile, immediately view the pile head through the smartphone camera and check the offset from the AR marker. If the virtual pile marker and the real pile overlap without offset, that proves the pile was installed at the design position. If there is a slight offset, the app displays numeric guidance such as “2 cm (0.8 in) east,” allowing you to understand the error amount on the spot. This way, you can instantly verify the accuracy of pile centers for all piles and take corrective measures as needed.

Furthermore, because installation position data and photos for each pile are saved to the cloud, there’s no need to remeasure back at the office. You can later review a list showing, for example, “Pile No. X was 3 cm (1.2 in) north of the design value,” making the preparation of as-built drawings and quality reports straightforward. Digitizing pile-center confirmation significantly reduces the workload for site supervisors and quality control staff.

Efficiency in pre-construction preparation

The AR pile-driving guidance app also brings great efficiency to pre-construction preparation. Traditionally, before work began, a surveying team would enter the site to verify reference points, do reconnaissance of pile positions, and make temporary markings. This required long on-site work and multiple personnel, but using AR coordinate navigation can simplify the process.

For example, site supervisors and responsible engineers can walk around the site with a smartphone and sequentially check planned pile positions in the app. If all planned pile coordinates are preloaded into the app, you can follow the on-screen navigation to visit each point in order. Even on large sites, you can quickly walk through all pile positions, make temporary marks as needed, and check for obstacles—completing reconnaissance solo.

Since design data is managed in the cloud, uploading the latest drawing coordinates from the office in advance ensures that accurate, synchronized position information is available on site. This prevents preparation errors due to overlooked drawings or data transcription mistakes. Thorough digital position checks before construction begins help prevent troubles such as “positions don’t match and require rework” once work starts. As a result, preparations before construction become smoother and the overall schedule gains buffer time.

Why site supervisors are satisfied

The benefits described above provide significant reassurance from the perspective of site supervisors who manage construction on site. First, the ability to objectively guarantee construction quality through improved pile-position accuracy and digital record management is of paramount importance. Supervisors can monitor in real time whether all piles are positioned according to design, and if deviations occur they can be detected and corrected immediately, greatly reducing the risk of discovering defects later and panicking. Quality inspection results backed by numeric data and photos make explanations to authorities and clients clear and persuasive.

Moreover, labor savings and improved safety make site management smoother. When positioning tasks are completed efficiently by few people, supervisors can allocate resources to other important tasks. Reduced hazardous work lowers the risk of occupational accidents, decreasing the supervisory burden for project-wide safety management. Because inexperienced staff can perform accurate work by following AR navigation, supervisors need not worry about variability in work quality. The need for supervisors to perform constant spot checks or issue repeated instructions is reduced, improving overall team coordination on site.

Furthermore, using AR plus high-precision positioning technology aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s “i-Construction” initiative, which promotes productivity improvements and DX on construction sites. Sites that actively introduce digital tools receive favorable evaluations from clients, allowing supervisors to confidently state “we manage accuracy with the latest technology.” A pile-driving guidance app trusted by site supervisors contributes to the overall sense of security and motivation across the construction team.

Simple surveying with LRTK

One convenient solution that brings RTK + AR pile-driving guidance to sites is LRTK. LRTK is an all-in-one site DX tool composed of a compact RTK-GNSS receiver that can be attached to a smartphone, a dedicated app, and cloud services, turning a smartphone into a high-precision surveying instrument. By simply attaching a pocket-sized receiver to a phone, you can obtain real-time current position with centimeter-level accuracy (cm level accuracy (half-inch accuracy)), and immediately display AR overlays based on the acquired coordinate data. The processes that were previously divided—surveying, layout, recording, and as-built management—can be completed with just one smartphone using LRTK.

No complicated operations or advanced knowledge are required; even people without surveying experience can follow the smartphone screen prompts to derive accurate pile-driving positions. It truly realizes “pile position layout that anyone can do.” By using LRTK for simple surveying, tasks that formerly consumed manpower and time are remarkably streamlined, and precision control is dramatically improved. As a strong ally that actively promotes on-site digitalization, LRTK will undoubtedly attract increasing attention.

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, a communication environment (internet connection) to obtain correction information for high-precision positioning and an outdoor environment with sufficient satellite visibility are required. With these in place, you can smoothly use AR coordinate navigation on site.

Q. Can precise pile-positioning be done with only the smartphone’s built-in GPS?

A. Unfortunately, typical smartphone GPS (standalone positioning) has errors on the order of several meters (several ft), so it is unsuitable for precise pile positioning. Achieving the centimeter-level accuracy discussed in this article requires augmentation via RTK-GNSS. In other words, only by using dedicated high-precision GNSS devices or correction services (network RTK base station information or satellite-based correction signals) can AR guidance realize its full potential. Solutions like LRTK make high-precision positioning possible even with a smartphone.

Q. Can people without surveying experience use it?

A. Yes. The AR pile-driving guidance app features an intuitive user interface designed so that even those without specialized surveying knowledge can use it. You simply follow the on-screen guidance to move and confirm, with no difficult calculations or advanced settings required. Once you learn the basic operations, even non-veteran staff can use it effectively on site. There are already cases where positioning work that used to depend on surveyors has been handled successfully by young staff alone.

Q. Will bad weather or poor signal conditions interfere with work?

A. Generally, the system can be used outdoors regardless of weather, but GNSS positioning requires an open view of the sky. Extreme weather such as heavy rain or heavy snow does not typically have a large impact on positioning accuracy (though satellite acquisition may take longer), but locations surrounded by buildings, tunnels, or indoors block satellite signals and prevent high-precision positioning. Also, network-type RTK corrections require communication coverage. In mountainous areas or other locations with unstable communication, offline augmentation methods such as Michibiki (CLAS) may be used. While AR markers can be displayed at night, the camera needs to capture the real scene, so a certain level of lighting at the site is required.

Q. Can this technology be used for purposes other than pile-driving?

A. Yes. Its applications extend beyond pile-driving. On building and civil engineering sites, AR coordinate navigation can be applied to foundation layout, marking positions for installing structures, measurement checks of as-built conditions, and more. It can also visualize the positions of buried pipes or cables in AR to aid safe excavation, or overlay 3D design models onto live site footage to intuitively share construction images. In short, AR visual guidance is valuable in any scenario where “accurate positioning” needs to be shown on site.