Pile-driving Work Is Changing! Improved Accuracy and Efficiency Achieved by AR Civil Engineering

Table of Contents

• Challenges of on-site pile-driving work

• Challenges of earthwork volume measurement

• What is AR pile-driving navigation

• How to use AR pile-driving navigation

• Benefits brought by AR guidance

• Immediate on-site earthwork volume measurement

• Simple surveying with LRTK

• Frequently Asked Questions

Challenges of on-site pile-driving work

In civil engineering and construction, installing foundation piles at the exact positions specified in the design is extremely important. Even a deviation of a few millimeters can lead to distortion of the superstructure or a reduction in the overall strength of the building, directly affecting safety and quality. Therefore, pile-driving work requires rigorous precision control that does not tolerate even millimeter-level errors.

However, laying out pile positions in the field exactly as marked on drawings is by no means easy. Normally, this layout (staking out) work is carried out by a team including skilled surveyors, who measure distances and angles from control points using a total station (optical surveying instrument) or tape measure and mark the ground accordingly. Even to accurately set out a single pile requires multiple stages of point verification, and on large sites where dozens of piles are installed, staking out positions alone can sometimes take more than a full day. It is a craft that depends on experience and manpower, and it represents a significant burden in terms of efficiency.

As long as people perform surveying and marking manually, the risk of human error cannot be avoided. Slight misreadings or transcription mistakes can lead to pile position shifts and cause rework in later stages. For example, on-site failures can occur such as setting up the surveying instrument on a tilt, which throws off the height reference and necessitates redoing the foundation heights. Even with careful double-checking, it is difficult to eliminate mistakes based solely on human attention, and ensuring pile-driving accuracy is a major source of pressure for site managers.

Conventional pile layout work also faces safety and work-environment constraints. Surveying on steep slopes or unstable footing places a heavy burden on workers, and marking tasks in areas where heavy machinery is operating increase the risk of collisions between machines and personnel. On sites surrounded by buildings or trees, the surveying instrument’s line of sight can be obstructed, preventing accurate measurement; in confined urban sites, long-distance staking out can be difficult. These physical constraints are also a significant concern.

In short, current pile-staking workflows require much time and manpower, while attention must also be paid to precision control and safety, making it a constant challenge to balance efficiency and accuracy.

Challenges of earthwork volume measurement

On civil sites, understanding how much excavated soil must be transported out and how much fill must be brought in—the earthwork volume—is also an important task. Accurate earthwork data are indispensable for progress management, transportation planning for surplus soil, and as-built reporting to project owners. However, accurately measuring earthwork volumes on site is not easy, and traditionally many measurements have been rough estimates based on experience and intuition. For example, to estimate the volume of a temporarily piled mound of soil, workers have manually shaped the pile, measured its height and width with a tape measure, and fitted it to an approximate geometric shape to calculate a rough estimate. Naturally, this method can introduce large errors and has relied heavily on the eye of skilled personnel.

There are methods to calculate earthwork volumes more accurately using three-dimensional surveying, but historically these required expensive specialized equipment such as drone aerial photography or terrestrial laser scanners, and could not be easily used on every job site. As a result, on many sites people have made approximate visual judgments like “it’s about this much,” or have later commissioned specialist firms to resurvey. If it takes time to grasp earthwork volumes, reporting and decision-making are delayed, affecting the overall efficiency of the construction. The difficulty of obtaining accurate earthwork volumes immediately on site has been a major challenge for schedule and cost control.

What is AR pile-driving navigation

A new approach that has emerged to solve these staking-out problems combines AR technology with high-precision positioning: AR pile-driving navigation. It overlays guidance information to specified coordinates onto the screen of a smartphone or tablet in augmented reality, so that virtual arrows or pins appear over the camera view of the site and guide the user to the exact point where a pile should be driven. It is easy to understand by imagining the AR mode in a map app that displays arrows to a destination. Applied to pile layout, it intuitively shows on your smartphone screen “this is the pile center.”

The key to AR pile-driving navigation is its integration 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 accuracy of several meters, which is insufficient for indicating precise pile positions on construction sites. What is used instead is high-precision GNSS positioning technology such as RTK, which reduces GPS errors to a few centimeters or less by using correction information from base stations or satellites. In Japan, the Quasi-Zenith Satellite System “Michibiki” provides a centimeter-level positioning augmentation service (CLAS) (cm level accuracy (half-inch accuracy)), making high-precision positioning available without installing dedicated base stations. By attaching an external high-precision GNSS receiver to a smartphone and enabling RTK, the current position can be obtained in real time with accuracy comparable to a total station.

The use of AR technology in surveying and construction within the civil engineering field—recently referred to as “AR civil engineering”—has been gaining attention. Digitizing on-site work is expected to be a key to dramatically improving both accuracy and efficiency.

How to use AR pile-driving navigation

When actually using AR pile-driving navigation to stake out pile positions, the rough procedure is as follows.

• Prepare design data: Prepare the coordinate data for piles and structures to be installed on site in advance and load them into the surveying app. You can import target points to your smartphone via the cloud from a list of coordinates on paper drawings or from CAD data.

• Set up high-precision GNSS: Attach an RTK-capable high-precision GNSS receiver to the smartphone for outdoor use, power it on, and start positioning. With reception of correction information, position accuracy improves to the centimeter level (half-inch accuracy) (the so-called “Fix solution”), and when the current position on the map stabilizes, you are ready.

• Start AR navigation: Select the coordinate point you want to navigate to in the app and start navigation. An arrow icon for guidance and the remaining distance will appear over the camera view, so follow the on-screen directions and walk in that direction. If the remaining distance becomes, for example, about 0.05 m (0.16 ft; 5 cm (2.0 in)), the spot at your feet is the exact position for the pile.

• Mark the point: When you reach the target point, mark the ground with a pile marker or chalk. Some apps allow you to press an “Arrived” button to record the coordinates of that point and save them to the cloud. Reviewing the data history of all installed locations after piling is complete helps with post-construction verification and quality records.

• Move to the next point: After marking one location, select the next coordinate point and begin guidance in the same way. Because there is no need to repeatedly measure dimensions from drawings, you can smoothly lay out multiple consecutive points.

By following these steps, you can use digitized design coordinate data directly on site. With cloud connectivity, if drawing data are updated they instantly synchronize to everyone’s devices, preventing construction errors due to outdated drawings. Sharing recorded pile positions and site photos on the cloud also allows remote progress monitoring, improving construction management efficiency.

Benefits brought by AR guidance

Introducing digital AR guidance on site delivers various advantages compared to traditional methods. The main benefits are summarized below.

• Significant reduction in work time and personnel: AR navigation dramatically shortens the manpower and time required for staking out piles. What used to take two or more surveying staff half a day can be completed by one person carrying a device with AR navigation. With fewer personnel, workers can be allocated to other tasks, allowing efficient progress even on labor-short sites. On large sites installing many piles, each worker can use their own smartphone plus GNSS device to stake out different points simultaneously, speeding up the whole team. Losses caused by waiting for surveying are reduced, and effects on shortening the construction schedule are especially noticeable on large projects.

• Improved measurement accuracy and reduced mistakes: Digital coordinate-based guidance eliminates variability caused by individual measuring habits or calculation errors. Because everyone works from the same design data, differences in final quality between veterans and newcomers or position errors caused by miscommunication can be prevented. With cloud-based instant sharing of drawing revisions, discrepancies from missed communications do not occur. A system that produces the same result regardless of who performs the work provides great reassurance for quality control.

• Improved safety: Because fewer people are required on site, entry into hazardous areas such as unstable footing or zones with operating heavy machinery can be minimized. Situations that can be safely guided remotely increase, reducing physical burden and accident risk for workers. Also, where optical surveying instruments struggle to maintain line-of-sight in complex terrain, GNSS positioning can capture points through gaps between obstacles, allowing flexible response even on narrow sites or layouts with many curves.

• Bridging the gap between design and site: AR pile-driving navigation also serves as a tool to close the gap between planned drawings and actual on-site work. Because AR can display virtual piles or structural models on the ground, you can proceed with construction while sharing the completion image. For example, you can place virtual piles or columns in AR before driving piles to check for interference with surroundings. This can reveal clashes that were not apparent on drawings and prevent rework. Seamlessly linking design, construction, and verification based on data strongly supports site DX (digital transformation).

Immediate on-site earthwork volume measurement

Not only does AR pile-driving navigation enable high-precision staking out, but recently it has also become practical to measure earthwork volumes on site using just a smartphone. Advances in point-cloud technology and photogrammetry have produced services that can obtain three-dimensional models of terrain and soil and calculate volumes without specialized equipment. For example, by simply recording a video around a mound of soil with a smartphone, point-cloud data can be automatically generated in the cloud and an approximate volume calculated. Using this, there is no longer a need to manually level soil and measure cross-sections; you can grasp earthwork volumes immediately on site.

In fact, LRTK includes functions that make it easy to perform point-cloud scanning and volume computation using a smartphone. From acquired 3D data, it can automatically calculate the amount of surplus soil generated by excavation and the fill volume required for backfilling. By comparing pre- and post-construction terrain data, you can determine the actual excavated volume (as-built), or instantly grasp shortages or excesses by comparing the current condition against the design model. The cloud can instantly generate volume reports and, if needed, visualize where and how much soil to add or remove with color-coded heat maps. These functions greatly streamline quantity management for earthworks.

Simple surveying with LRTK

LRTK was developed as an all-in-one site DX tool that combines high-precision RTK positioning, AR technology, and point-cloud scanning so that anyone can easily perform pile-staking and quantity measurement. LRTK consists of a compact RTK-GNSS receiver that attaches to a smartphone, a dedicated app, and cloud services, turning a pocket smartphone into a surveying instrument with centimeter-level accuracy (half-inch accuracy). Just attach the pocket-sized GNSS antenna to your phone and you can obtain high-precision real-time position information, and based on that data you can immediately perform AR displays and point-cloud analysis on site. Processes that were traditionally divided among different trades or separate workflows—surveying, staking out, as-built management, and reporting—can be completed with a single smartphone using LRTK.

No complicated operations or specialist knowledge are required; even people without surveying experience can derive accurate pile-driving positions by following on-screen guidance. It is truly an innovative tool that realizes “staking out anyone can do.” LRTK also includes one-touch measurement functions for distance, area, and volume. You can calculate distance between two points on point-cloud data, compute arbitrary-area areas, or derive earthwork volume differences from multiple terrain datasets, allowing non-experts to instantly obtain the numbers they need. Because it streamlines even the recordkeeping and quantity calculations after measurement, site productivity and precision control dramatically improve. LRTK is a cutting-edge technology that supports i-Construction promoted by the Ministry of Land, Infrastructure, Transport and Tourism, and is a reliable ally that strongly advances digital transformation in the construction industry.

Frequently Asked Questions

Q. What equipment and environment are required to use AR pile-driving navigation? A. Basically, you need a smartphone (or tablet) that supports AR guidance and a high-precision GNSS receiver capable of centimeter-level positioning (half-inch accuracy). Specifically, attach an RTK-capable GNSS unit to the smartphone and prepare a communication environment (such as mobile network) for receiving correction data. In an outdoor environment with sufficient satellite signal reception, this combination enables smooth use of AR pile-driving navigation on site.

Q. Can you perform precise stake-out using only the smartphone’s built-in GPS? A. Unfortunately, the standalone GPS in typical smartphones can have errors of several meters, making it unsuitable for precision pile staking. RTK-GNSS corrections are indispensable to achieve centimeter-level accuracy (half-inch accuracy). In other words, only by using dedicated high-precision GNSS devices or augmentation services from satellites or networks can AR guidance demonstrate its full value. Solutions like LRTK make high-precision positioning possible even with a smartphone, so you can be confident in accuracy.

Q. Can people without surveying experience use it effectively? A. Yes. It is designed for intuitive operation, so people without specialized surveying knowledge can handle it. You simply follow the guidance displayed on the smartphone and move or mark the point, so no complex calculations or settings are necessary. Once you learn the basic operations, even non-veterans can use it effectively on site. There are actual cases where staking-out work that previously required a surveyor was successfully performed by younger staff using the system.

Q. Do weather or signal conditions affect the work? A. Basically, it can be used outdoors regardless of weather. However, GNSS positioning requires an open sky, so accuracy cannot be achieved in areas surrounded by tall buildings, inside tunnels, or indoors. If network RTK corrections are used, you need to be within a communication area. In regions with unstable signals, such as mountainous areas, services that receive augmentation signals directly from satellites (for example, the Michibiki CLAS) are sometimes used. AR display itself works at night, but because it overlays the live camera image, a minimum level of lighting is required.

Q. Can this technology be applied to tasks other than pile driving? A. Yes, its applications extend beyond pile driving. On building and civil sites, AR coordinate navigation can be applied to marking building foundations, equipment installation positions, and as-built measurement verification. It can also visualize the locations of buried pipes and cables in AR to assist safety checks during excavation. Moreover, 3D BIM/CIM design data can be overlaid on live site footage to intuitively share construction imagery during the design stage. In short, wherever “showing accurate positions on site” is necessary, intuitive AR guidance can be highly effective.