Immediate On-Site Layout! AR Pile-Driving Navigation Lets Anyone Place Points with High Accuracy

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

On civil engineering and construction sites, pile-driving work to install piles that form the foundation of structures, and layout work to mark the precise positions of buildings and equipment on site, are indispensable. Based on numerical coordinates on drawings, positions must be established on site without even a few centimeters (a few in) of error, but traditional pile layout is by no means easy. Normally, this alignment requires advanced surveying skills and considerable effort: a team including a surveyor uses a total station (optical surveying instrument) and tape measures to mark pile positions by measuring distances and angles from control points. Even placing a single pile can require multiple measurement steps, and installing dozens of piles over a large site can easily take a full day or more just for layout work.

Because surveying and marking are done manually, there is also the risk of human error. Small misreads or recording mistakes can lead to displaced pile positions, causing construction errors or rework in later stages. For example, if the surveying instrument was not set up level, the height reference can be off and the foundation height may need to be redone after construction. Furthermore, work on steep slopes or unstable footing can endanger workers or slow progress. Marking piles in areas where heavy machinery is operating increases the risk of accidents due to proximity between machines and workers. In addition, sites with many existing structures or trees can prevent line-of-sight for surveying instruments and make accurate measurement impossible, and narrow urban sites can make long-distance layout difficult. In short, traditional pile layout is labor- and time-intensive and poses challenges for accuracy control and safety.

Challenges of earthwork volume measurement

On site, calculating earthwork volumes—how much soil to excavate and how much fill to place—is also extremely important. Knowing earthwork volumes is essential for progress reporting, planning transport for surplus soil, and reporting as-built quantities to the client. However, accurate earthwork measurement requires effort, and conventional sites often rely on experience and intuition or rough measurements with simple tools. For example, to estimate the volume of a temporary mound of soil (surplus soil or fill), craftsmen would shape the mound and use tape measures to record height and width, then fit it to a rough geometric shape to estimate the volume. Naturally, this method can produce significant errors and relies heavily on skilled judgment.

Although three-dimensional surveying can produce accurate earthwork volumes, it has traditionally required specialized equipment such as drone aerial photography or terrestrial laser scanners, and could not be easily used on every site. As a result, on many sites people estimate by eye—“about this much”—or specialist staff measure later and report results afterward. When earthwork measurement takes time, decision-making and reporting are delayed and can affect overall construction efficiency. The inability to obtain accurate earthwork quantities immediately on site is a major issue for schedule and cost management.

What is AR pile-driving navigation

A new approach that addresses these challenges is AR pile-driving navigation, which leverages AR technology and high-precision positioning. This system overlays guidance information for specified coordinates on the screen of a smartphone or tablet. Simply put, it displays virtual arrows or pins over the live camera view to navigate workers to the exact points where piles should be driven. Think of the AR navigation functions in car navigation or map apps—this applies the same concept to pile layout on construction sites, intuitively indicating “this is the pile position” through the phone’s screen.

The key to AR pile-driving navigation is integration with positioning technology that can determine the smartphone’s current location with centimeter-level (half-inch accuracy) precision. Built-in smartphone GPS usually has errors of several meters (several ft), which is insufficient for precise pile locations on construction sites. What is used instead is high-precision GNSS positioning such as the RTK (Real Time Kinematic) method, which uses correction signals from base stations or satellites to reduce GPS errors to a few centimeters (a few in). In Japan, centimeter-class positioning augmentation services using the Quasi-Zenith Satellite System “Michibiki” (CLAS) have been developed, making high-precision positioning available without installing dedicated base stations. By attaching an external high-precision GNSS receiver to a smartphone and performing RTK positioning, users can obtain current positions with accuracy comparable to a total station.

Combining high-precision position information with AR display transforms pile-driving guidance into a “navigation system for construction sites.” The direction and distance to the target point are displayed in real time on the phone’s live view, and the worker can simply walk in the direction the arrow points to reach the correct location. For example, when an app selects a target pile point, guidance such as “5 cm (2.0 in) east to target” or “10 cm (3.9 in) north to target” can appear on the screen. By following these instructions and adjusting a few steps, the worker can stand precisely at the design point. When the worker reaches the target point, a virtual pile (an AR marker) rises from the ground in the camera view, clearly indicating “this is the pile tip position.” Even inexperienced staff can pinpoint accurate points without confusion by following the on-screen arrows and pins.

How to use AR pile-driving navigation

Here is an overview of the typical steps to perform pile layout using AR pile-driving navigation.

• Prepare design data: Prepare the design coordinate data for piles and structures to be installed on site in advance and load them into the app. You can import target points from a coordinate list on drawings or CAD data (DXF/DWG formats, etc.) to the smartphone via the cloud.

• Connect GNSS receiver to smartphone: Attach and activate an RTK-capable high-precision GNSS receiver on the smartphone outdoors and start positioning. When correction information is received and position accuracy improves to centimeter-level (half-inch accuracy), i.e., achieving a “Fix” solution, and the current position on the map stabilizes, you are ready to begin surveying.

• Start navigation: Select the target coordinate point to be guided in the app and start navigation. Guidance arrows and distance displays appear over the camera view, and by moving with the smartphone you approach the target point. For example, when you are within about 0.05 m (0.16 ft) (5 cm (2.0 in)) remaining distance, the spot beneath your feet is the precise location for pile driving.

• Mark the point: When you reach the target point, mark the ground with a pile or chalk. Some apps allow you to tap an “Arrive” button to record the point’s coordinates and save them to the cloud. After pile installation, you can review records of all installation locations as data.

• Proceed to the next point: After marking one location, select the next coordinate point and start guidance in the same way. Since you don’t need to spread out paper drawings and measure each dimension, you can carry out layout tasks continuously and smoothly.

With these steps, digitized coordinate data from drawings can be used directly on site. Using cloud connectivity, you can instantly respond to design changes and synchronize updated drawings across all devices. This prevents issues such as “working from an old drawing” or “installing at the wrong position due to communication errors.” If measured pile positions and site photos are shared on the cloud, progress can be checked remotely from the office, improving construction management efficiency.

Benefits brought by AR guidance

Digital guidance via AR pile-driving navigation brings significant benefits to the site. First, it greatly reduces personnel and working time. Layouts that previously required two or more surveying staff can be completed by one person walking with the device. Fewer people mean more flexibility in personnel allocation and potential cost savings from reduced labor. On large sites where multiple points need layout in parallel, each worker with their own smartphone and GNSS can locate different points simultaneously, speeding up the entire team. Traditionally, the surveying crew had to set points one by one in order, but with the new technology each worker can perform layout at different locations at the same time. This reduces schedule loss from waiting for survey crews and is especially effective on large-scale projects.

Second, the reduction of measurement errors and variability is a major advantage. Digital coordinate-based guidance ensures everyone follows the same design data, eliminating subtle deviations caused by individual measuring habits. It prevents subjective errors such as “veteran and novice produce different finish accuracies” or “differences in interpretation lead to inconsistent control point selection.” With cloud data sharing, everyone uses the latest information immediately when drawings are revised, preventing discrepancies from communication mistakes. This system ensures the same result regardless of who performs the work, providing strong quality-control assurance.

Improved safety is also notable. Because tasks can be completed by a single person, the number of people on site can be minimized, reducing entry into hazardous areas such as unstable footing or zones with operating heavy machinery. More situations can be guided remotely and safely, reducing physical burden and accident risk for workers. GNSS positioning also allows measurement of points even in complex terrain where line-of-sight for physical surveying instruments is difficult. Digital guidance can flexibly handle narrow sites and layouts with many curves.

Moreover, AR pile-driving navigation is useful as a tool to bridge the gap between design drawings and the site. AR can display virtual piles or structural models on the ground, allowing stakeholders to share the completed image on site before construction. For example, you can virtually erect piles or columns in AR prior to installation to check positional relationships with the surroundings. This helps prevent on-site discovery of interferences that were not apparent on the design drawings. Thanks to high-precision guidance that keeps AR displays aligned, it becomes possible to seamlessly connect planning, construction, and verification based on data.

Immediate on-site earthwork volume measurement

Beyond high-precision positioning for pile layout, smartphone-based immediate on-site earthwork measurement has become a reality. Advances in point cloud and photogrammetry technologies have produced tools that can obtain 3D models of site terrain and soil volumes and calculate volumes without special equipment. A representative example is smartphone-and-cloud earthwork measurement services. For instance, by walking around a mound of soil and recording video with a smartphone, a 3D point cloud can be generated in the cloud and the approximate volume automatically calculated. This eliminates the need for workers to shape the mound or measure cross-sections and calculate volumes using the average-section method. In short, “immediate on-site earthwork measurement” becomes possible.

LRTK also includes functions that make point cloud scanning and volume calculation easy with a smartphone. Using the obtained 3D data, it can automatically compute volumes of excavated soil and the fill volume required for backfilling. For example, by comparing pre- and post-construction terrain data, the actual excavated volume (as-built) can be calculated. By comparing the design ground model with current terrain data, you can instantly determine excess excavation or insufficient fill. If you specify an area of interest on the cloud, a volume report is generated instantly. A color-coded heatmap can visualize “where and how much to excavate or fill,” and if necessary, overlaying that heatmap in AR on the real site provides intuitive instructions to on-site workers and heavy equipment operators.

Thus, using smartphones and cloud technology, earthwork calculations that once took days can now be completed on site. With real-time accurate quantity data, you can immediately estimate the number of trucks needed for surplus soil or compile progress payment reports the same day, dramatically improving construction management speed. Work no longer stalls while waiting for earthwork calculations, accelerating the site PDCA cycle.

Simple surveying with LRTK

Combining high-precision RTK positioning, AR technology, and point cloud scanning, LRTK has emerged as an all-in-one solution that enables anyone to easily perform pile layout and quantity measurement. LRTK consists of a compact RTK-GNSS receiver attached to a smartphone, a dedicated app, and a cloud service, turning the smartphone into a high-precision surveying tool. By simply attaching a pocket-sized GNSS receiver to a smartphone, you can obtain centimeter-level (half-inch accuracy) real-time position information, and immediately perform AR display and point cloud analysis on site based on the acquired data. Processes that used to be divided among specialists—surveying, layout, as-built management, and reporting—can be completed with just a smartphone using LRTK.

No complicated operations or specialized knowledge are required: even those without surveying experience can derive accurate pile positions by following the guidance on the smartphone screen. It is truly an innovative tool that realizes “pile layout anyone can do.” LRTK also includes functions to easily measure distances, areas, and volumes. You can calculate the distance between two points on point cloud data, compute area of a specified region, or derive earthwork differences between multiple terrain datasets; even without being a surveyor, you can obtain the numbers you need with a single button press. Because it streamlines recording and quantity calculation desk work after measurement, site productivity and accuracy control are significantly improved. LRTK is a cutting-edge technology compatible with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative, and is a reliable ally to drive digital transformation on sites.

Frequently asked questions

Q. What equipment and environment are necessary to use AR pile-driving navigation? A. Basically, you need a smartphone (or tablet) that supports AR guidance and a GNSS receiver that can provide centimeter-level (half-inch accuracy) positioning. Specifically, attach an RTK-capable high-precision GNSS unit to the smartphone and prepare a communication environment (mobile network, etc.) to receive correction information. In outdoor environments with sufficient satellite reception, combining these components allows smooth use of AR pile-driving navigation on site.

Q. Can accurate layout be achieved with only built-in smartphone GPS? A. Unfortunately, general smartphone GPS (standalone positioning) has errors of several meters (several ft), so it is unsuitable for precise pile layout. To achieve the centimeter-level accuracy introduced in this article, RTK-GNSS augmentation is indispensable. In other words, the true value of AR guidance is realized only when using dedicated high-precision GNSS devices or correction services from satellites and networks. Solutions like LRTK enable high-precision positioning on smartphones, so you can be assured.

Q. Can non-experts use it effectively? A. Yes. The system is designed for intuitive operation, so people without specialized surveying knowledge can use it. You only need to follow the guidance displayed on the smartphone screen to move and check positions—no difficult calculations or settings are required. Once you learn the basic operations, even non-experts can make effective use of it on site. In practice, tasks that used to require surveyors have successfully been performed by younger staff using this technology.

Q. Do weather or radio conditions affect the operation? A. Generally, it can be used outdoors regardless of weather. However, GNSS positioning requires an open sky, so accuracy cannot be achieved in locations surrounded by tall buildings, inside tunnels, or indoors. If using network-based RTK corrections, you must be within a communication coverage area. In mountainous or other areas with unstable communication, services that provide direct augmentation signals from satellites (for example, Michibiki’s CLAS) are sometimes used. Note that AR displays themselves work at night, but minimum lighting is required for the camera to capture the real scene.

Q. Can this technology be used for applications other than pile-driving? A. Yes; its applications extend beyond pile-driving. In construction and civil engineering, AR coordinate navigation can be applied to foundation layout, marking machine installation positions, and as-built measurement verification. It can also visualize the positions of buried pipes or cables in AR for safe excavation, overlay 3D BIM design data onto site footage to intuitively share construction images, and more. In short, in any situation where “accurate positions must be shown on site,” AR’s intuitive guidance will prove valuable.