Table of Contents

• Challenges of on-site piling work

• Challenges of earthwork volume measurement

• What is AR piling navigation

• How to use AR piling navigation

• Benefits brought by AR guidance

• Instant on-site earthwork volume measurement

• Simple surveying with LRTK

• Frequently Asked Questions

Challenges of on-site piling work

On civil engineering and construction sites, staking work to install piles that form the foundation of structures, and layout marking to show the exact positions of buildings and equipment on site, are indispensable. Based on the numerical coordinates on drawings, positions must be established on site with no deviation of even a few centimeters (a few inches), but traditional staking is by no means easy. Normally, this alignment requires advanced surveying skills and considerable effort: a team including surveyors 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 surveying steps, and marking dozens of piles across a wide site can easily take a whole day or more just for layout work.

Because surveying and marking are done manually by people, there is also the risk of human error. Small misreadings or recording mistakes can shift pile positions and cause construction errors or rework in later stages. For example, if a surveying instrument was not set level, the vertical reference can be off and the foundation height had to be redone after construction. Moreover, work on steep slopes or areas with poor footing can endanger workers or make tasks difficult. Marking piles in zones where heavy machinery is operating raises the risk of accidents due to proximity between machines and personnel. In addition, sites with many existing structures or trees may block the line-of-sight of surveying instruments and prevent accurate measurement, and tight urban sites can make long-distance layout marking difficult—these are physical constraints of the traditional approach. In short, conventional pile-staking layout is labor- and time-intensive and faces challenges in accuracy control and safety assurance.

Challenges of earthwork volume measurement

On site, calculating how much soil to excavate and how much fill to place—earthwork volume—is also extremely important. Knowing volumes is essential for progress reporting, planning transport of surplus soil, and as-built reporting to clients. However, measuring earthwork accurately is time-consuming, and in traditional sites people often rely on experience and intuition or measure roughly with simple tools. For example, to estimate the volume of a stockpile (surplus soil or fill), craftsmen would shape it and then measure height and width with a tape measure, approximating volume by fitting it to a simple geometric shape. Naturally, this method can produce significant errors and depends heavily on the skill and intuition of experienced workers.

There are also accurate methods using three-dimensional surveying, but traditionally these required specialized equipment such as drone aerial photography or terrestrial laser scanners and were not readily usable on every site. As a result, in many actual sites judgments are made by eye—“this much, roughly”—or measurements are left to specialist staff who report later. Delays in earthwork measurement slow decision-making and reporting, affecting overall construction efficiency. The inability to obtain accurate earthwork volumes instantly on site is a major issue for schedule and cost control.

What is AR piling navigation

A new approach to solve these problems uses augmented reality (AR) combined with high-precision positioning: AR piling navigation. This system overlays guidance information for specified coordinates on the screen of a smartphone or tablet. Simply put, it displays virtual arrows or pins on the live camera view of the site and navigates workers to the exact points where piles should be driven. It is similar to AR navigation features in car navigation or map apps, applied to pile-staking layout so the smartphone screen intuitively shows “this is the pile position.”

The key to making AR piling navigation work is linking AR with positioning technology that can determine the smartphone’s current position to centimeter-level accuracy (cm level accuracy (half-inch accuracy)). Ordinary smartphone GPS has errors of several meters, which is insufficient to indicate precise pile positions on a construction site. Instead, high-precision GNSS positioning methods such as RTK (Real Time Kinematic) are used; they use correction signals from base stations or satellites to reduce GPS errors to a few centimeters (a few inches). In Japan, the quasi-zenith satellite system “Michibiki” provides centimeter-level positioning augmentation services (CLAS), making high-precision positioning available without installing a dedicated base station. By attaching an external high-precision GNSS receiver to a smartphone and using RTK, the current position can be obtained with accuracy comparable to a total station.

Combining high-precision position information with AR display evolves on-site pile guidance into what can be called a “construction-site car navigation.” Direction and distance to the target point are displayed in real time on the live camera view, and workers can reach the correct position simply by walking in the direction indicated by an arrow. For example, when a user selects a desired pile point in the app, on-screen guidance like “5 cm (2.0 in) east to the target” and “10 cm (3.9 in) north” can appear. By adjusting a few steps according to the instructions, one can stand precisely at the design point. When the target point is reached, a virtual pile (an AR marker) rises from the ground in the camera view, clearly showing “this is the pile tip position.” Even inexperienced staff can identify the correct point simply by following the on-screen arrow and pin.

How to use AR piling navigation

Here is a general procedure for using AR piling navigation for pile layout.

• Prepare design data: Prepare the design coordinate data for piles and structures to be installed at the site in advance and load them into the app. Points can be imported from a coordinate list on drawings or CAD files (DXF/DWG etc.) to the smartphone via the cloud.

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

• Start navigation: Select the target coordinate point you want to navigate to in the app and start navigation. Guidance arrows and distance indicators will appear on the camera view, and by carrying the smartphone and moving you will approach the target point. For example, when you are within about 0.05 m (0.16 ft) — about 5 cm (2.0 in) — of the target, the spot beneath your feet is the exact position for pile driving.

• Mark the point: Upon reaching the target point, mark the ground with a pile or chalk. Some apps let you tap an “Arrived” button to record that point’s coordinates and save them to the cloud. After piling is complete, you can review records of all installed locations as data.

• Proceed to the next point: After marking one point, select the next coordinate and start guiding in the same way. Because there is no need to spread paper drawings and measure out each dimension, you can proceed smoothly and continuously with layout work.

Following these steps lets you use digital drawing coordinates directly on site. With cloud linkage, design changes are immediately available and the latest data is synchronized to everyone’s devices when drawings are updated. This prevents problems like “working from an old drawing” or “installing in the wrong place due to miscommunication.” Sharing measured pile positions and site photos on the cloud also lets office staff check progress remotely, improving construction management efficiency.

Benefits brought by AR guidance

Digital guidance using AR piling navigation brings significant benefits to the site. First, it greatly reduces personnel and work time. Traditional staking that required two or more surveying staff can be completed with just one person walking with the equipment using AR guidance. Fewer staff frees up manpower for other tasks and reduces costs. On large sites with many points, multiple workers can each use their own smartphone + GNSS to stake different points simultaneously, speeding up the whole team. Previously, survey teams had to mark points sequentially, but with the new technology each worker can simultaneously perform layout work at different locations. This reduces delays waiting for surveying and is especially effective for large-scale projects.

Next, AR guidance significantly reduces measurement errors and variability. Because guidance is based on digital coordinates shared by everyone, subtle differences caused by individual measurement habits disappear. It prevents subjective errors such as “veteran and novice produce different finish accuracies” or “interpretation differences cause inconsistent control points.” Cloud-shared data ensures everyone uses the latest information when drawings are revised, eliminating discrepancies caused by communication errors. A system where anyone gets the same result provides strong assurance for quality control.

Safety improvements are also notable. Because tasks can be completed by one person, the number of personnel exposed to hazards is minimized, reducing entry into dangerous areas such as poor footing or zones with operating heavy machinery. Remote guidance becomes more feasible, reducing physical burden and accident risk for workers. GNSS positioning can measure points even in complex terrains where line-of-sight for physical surveying instruments is difficult, allowing flexible response in narrow sites or curved layouts.

Furthermore, AR piling navigation is useful as a tool to bridge the gap between design drawings and the site. AR can display virtual piles or structure models on the ground so you can share the completed image on site while proceeding with construction. For example, you can place virtual piles or columns in AR before driving piles to check spatial relationships with surroundings. This helps prevent on-site clashes that were not noticed on drawings. With high-precision guidance that keeps AR aligned, you can seamlessly connect planning, construction, and verification based on data.

Instant on-site earthwork volume measurement

Not only does AR piling navigation enable high-precision layout, but recently instant on-site earthwork volume measurement using smartphones has become a reality. Advances in point cloud and photogrammetry technologies enable obtaining three-dimensional models of site terrain and stockpiles and calculating volumes without special equipment. A representative example is a smartphone-and-cloud earthwork measurement service. For instance, walking around a stockpile and recording a video with a smartphone can generate a 3D point cloud on the cloud and automatically calculate an approximate volume. This eliminates the need for workers to shape piles, measure cross-sections, or use average-section methods. It truly makes instant on-site earthwork volume measurement possible.

LRTK also includes functionality to easily perform point cloud scans with a smartphone and calculate volumes. Based on the acquired 3D data, it can automatically compute the volume of excavated soil or the fill required for backfilling. For example, by comparing terrain data before and after construction, you can calculate the actual excavated volume (as-built). From the difference between the design ground model and the current terrain data, you can instantly determine excess excavation or deficient fill. If you specify an area on the cloud, a volume report is generated instantly. A color-coded heat map can visualize “where and how much to excavate or fill,” and overlaying that heat map on the real site via AR can intuitively direct workers and equipment operators.

Thus, by leveraging smartphones and the cloud, earthwork volume calculations that once took days can now be completed on site. Having accurate quantity data in real time enables immediate estimation of truckloads for surplus soil and same-day progress reporting, dramatically speeding up construction management. Work no longer halts while waiting for volume calculations, accelerating the PDCA cycle on site.

Simple surveying with LRTK

Combining RTK high-precision positioning, AR, and point cloud scanning, LRTK emerged as an all-in-one site DX 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 instrument. By attaching a pocket-sized GNSS receiver to a smartphone you can obtain centimeter-level position information in real time and immediately perform AR displays and point cloud analysis on site. Processes that were previously divided—surveying, layout marking, as-built management, and reporting—can now be completed with a single smartphone.

No complicated operations or specialized knowledge are required; even those without surveying experience can find correct pile positions by following on-screen guidance. It is truly an innovative tool that realizes “pile staking anyone can do.” LRTK also includes features to easily measure distances, areas, and volumes. You can calculate the distance between two points on point cloud data, compute the area of a specified region, or derive volume differences from multiple terrain datasets—so non-surveyors can obtain the numbers they need with the push of a button. Because it streamlines post-measurement recordkeeping and quantity computations, site productivity and accuracy control improve markedly. LRTK is compatible with the i-Construction initiatives promoted by the Ministry of Land, Infrastructure, Transport and Tourism and is a reliable partner for accelerating digital transformation on site.

Frequently Asked Questions

Q. What equipment and environment are required to use AR piling navigation? A. Basically, you need a smartphone (or tablet) that supports AR guidance and a GNSS receiver capable of centimeter-level 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 open outdoor environments where satellites provide sufficient signals, combining these components enables smooth use of AR piling navigation on site.

Q. Can accurate layout be done with only the smartphone’s built-in GPS? A. Unfortunately, ordinary smartphone GPS (standalone positioning) has errors of several meters and is unsuitable for precise pile staking. Achieving the centimeter accuracy described in this article requires RTK-GNSS augmentation. In other words, dedicated high-precision GNSS devices or correction services from satellites or networks are essential for AR guidance to realize its full potential. Solutions like LRTK make high-precision positioning possible even with a smartphone.

Q. Can non-experts use it effectively? A. Yes. It is designed for intuitive operation, so those without specialized surveying knowledge can use it. Users simply follow the guidance on the smartphone screen—no difficult calculations or settings are required. Once basic operations are learned, even non-experts can use it effectively on site. In practice, tasks that previously required surveyors have been performed successfully by younger staff using this technology.

Q. Do weather or radio conditions affect operation? A. Generally, it can be used outdoors regardless of weather. However, GNSS positioning requires an open view of the sky, so accuracy will degrade in locations surrounded by tall buildings, tunnels, or indoors. If you use network-based RTK corrections, you must be within a communication area. In mountainous regions with unstable communications, services that receive augmentation signals directly from satellites (for example, Michibiki’s CLAS) may be used. AR displays themselves can work at night, but some minimum lighting is needed for the camera to capture the real scene.

Q. Can this technology be used for applications other than piling? A. Yes. Its applications extend beyond piling. In building and civil works, AR coordinate navigation can be applied to foundation layout, machine installation marking, and as-built measurement verification. It can also visualize the locations of buried pipes and cables in AR to assist safety checks during excavation, or overlay 3D BIM design data on site footage to intuitively share construction imagery. In short, AR guidance is effective in any scenario where accurate on-site positioning is required.