Improving Pile-Driving Guidance with On-Site DX: Big Accuracy Gains from GNSS Positioning + AR Guidance

Table of contents

• Introduction

• Challenges of Traditional Pile-Driving Guidance

• Improving Pile-Driving Guidance with GNSS Positioning + AR

• Error Reduction and Accuracy Improvements from AR Pile-Driving Guidance

• Centimeter-Level Positioning with RTK

• Further Possibilities for On-Site DX with Smartphone Surveying

• Conclusion: A New Era of Simple Surveying Enabled by LRTK

• FAQ

Introduction

In recent years, the construction industry has focused on improving on-site work efficiency through ICT and DX (digital transformation). However, in practice, positioning tasks such as surveying and pile-driving still consume significant time and manpower, and challenges such as labor shortages and the aging of skilled technicians are becoming more serious.

A promising solution to these issues is the fusion of smartphones, GNSS (global navigation satellite system) positioning technology, and AR (augmented reality) for on-site guidance. By obtaining centimeter-level position information with high-precision GNSS positioning (such as RTK) and overlaying it onto live site imagery via AR, on-site work can now be supported intuitively and accurately. Simply combining a smartphone with a small, high-precision GNSS receiver allows pile-driving guidance tasks that once required dedicated surveying instruments and a multi-person team to be performed easily by a single person.

This article focuses on pile-driving guidance in the context of on-site DX and explains in detail the new construction-support methods that leverage GNSS positioning and AR technology. From the challenges of traditional methods to the innovations brought by the latest technologies and the resulting benefits, we summarize everything clearly and conclude with solutions for practical “simple surveying” on site.

Challenges of Traditional Pile-Driving Guidance

Traditional methods for pile-driving (positioning) at construction sites involved various inefficiencies. To stake out points on the ground according to design drawings, it was common to set up a dedicated surveying instrument such as a total station on a tripod and have two people—a surveyor and an assistant—do the work. Even to mark a single point, cumbersome steps were required: measuring distances from a reference point with a tape measure, marking, and the surveyor signaling while the assistant adjusted the stake position. On large sites with many stake points, surveying and pile-driving alone could take more than a full day.

There is also a significant risk of human error inherent to manual work. Small reading mistakes or marking errors can shift stake positions, causing rework later in construction or even misalignments in the structure itself. The time and effort required to re-stake piles or correct later-stage work have been factors that reduce overall site productivity. Moreover, inexpensive GPS devices traditionally had errors of 5–10 m and could not be used for precise pile-driving, forcing reliance on expensive surveying equipment and skilled technicians. As a result, positioning work incurred substantial costs and time, burdening small and medium-sized projects. The aging of skilled surveyors and the shortage of successors further exacerbates the situation, and maintaining traditional methods is expected to become increasingly difficult.

Improving Pile-Driving Guidance with GNSS Positioning + AR

The key to solving the above issues is automating pile-driving guidance by combining GNSS positioning data and AR display. If coordinate data for stake positions defined in the construction drawings are preloaded into a smartphone app, the system can compare current position from high-precision GNSS and display the remaining distance and direction to the target point in real time. For example, the screen can show numeric guidance such as “10 cm north, 5 cm east to the target point,” allowing workers to reach the precise location by moving only a few steps according to the instructions. Tasks that previously required multiple people using tape measures can now be completed by a single worker with a smartphone.

Using GNSS+AR guidance dramatically reduces the labor and time required for pile-driving. There is no need to prepare dedicated equipment or have a surveying team stand by, enabling immediate surveying and staking when needed. Since one person can complete the work, personnel scheduling is simplified, and positioning can be performed smoothly even on sites with labor shortages. Reports from sites that adopted state-of-the-art digital pile-driving systems indicate substantial time savings. For example, pile-driving surveying that previously required two people and more than a full day was completed by one person in less than half a day after introducing digital tools, clearly demonstrating efficiency gains.

Error Reduction and Accuracy Improvements from AR Pile-Driving Guidance

The true value of combining GNSS and AR for pile-driving guidance lies in its high accuracy and error-reduction effects. By superimposing virtual markers or marks that indicate the target pile position onto the smartphone camera feed, workers can intuitively identify the exact point to drive the pile through the screen. Even without advanced surveying skills, workers can set piles by following visual guidance, significantly reducing human errors such as misjudging positions or misreading survey points. Naturally, re-staking is greatly reduced and rework to correct misalignments in later stages is almost eliminated.

Sites that have implemented GNSS×AR pile-driving guidance report results such as “reduced variation in pile positions, and all points passed post-construction accuracy checks as per the drawings” and “no more redoing pile-driving, allowing safe progression to the next steps.” The combination of AR visualization and high-precision positioning has dramatically increased pile-driving accuracy. Positioning tasks that once caused anxiety can now be performed accurately by anyone with the help of digital technology.

As described above, introducing GNSS positioning and AR guidance dramatically improves the efficiency and accuracy of pile-driving tasks. The main benefits are summarized below:

• Labor reduction: tasks can be done by one person, greatly reducing required personnel

• Time savings: surveying and pile-driving time is significantly reduced

• Accuracy improvement: positioning accuracy increases and construction quality stabilizes

• Cost reduction: fewer re-measurements and rework lower total costs

• Safety improvement: less transport and setup of heavy equipment reduces safety risks

• Elimination of dependence on individuals: anyone can perform tasks without specialized skills

Centimeter-Level Positioning with RTK

So why is such high-precision positioning possible with a smartphone? The key is RTK (Real Time Kinematic), a representative method for high-precision GNSS positioning. RTK dramatically improves accuracy by applying real-time corrections to satellite position data: both a base station at a reference point and a rover (mobile unit) perform GNSS positioning simultaneously. Error information obtained at the base station is sent in real time to the rover for correction, reducing typical positioning errors of several meters to a few centimeters or less. In Japan, services such as the Geospatial Information Authority’s reference station network and the quasi-zenith satellite system “Michibiki” provide centimeter-level positioning augmentation services (CLAS), making RTK positioning possible without installing a local base station on site. Recent smartphones include high-performance multi-band GNSS chips and, when paired with an external compact antenna-integrated receiver, can achieve centimeter-level positioning comparable to dedicated surveying instruments. The advent of such “smartphone RTK” enables anyone to easily obtain high-precision position information, forming the foundation for improved accuracy and efficiency in tasks such as pile-driving guidance and various construction-management duties.

Further Possibilities for On-Site DX with Smartphone Surveying

Smartphone surveying that combines GNSS and AR holds many opportunities to further advance on-site DX beyond pile-driving guidance. For example, in infrastructure inspections and post-construction as-built management, a “coordinate photo” feature that tags a photo with the precise capture coordinates and camera orientation is useful. Storing geotagged photos in the cloud makes it clear later on “where and from what angle a photo was taken,” greatly improving efficiency for comparing changes over time and preparing reports. Combined with AR, it is also possible to display icons in the real world indicating where previous inspection photos were taken and capture new photos from the same angle.

AR can also overlay 3D design data on site to check as-built conditions on the spot, visualize underground buried structures to safely proceed with excavation, or visualize boundary markers and reference points to confirm them. In fact, a major construction company has started using BIM data combined with AR to visualize unseen piping routes inside walls before construction to prevent mistakes. This “visualization” via AR smooths on-site information sharing, significantly reducing communication loss and preventing human error.

Thus, smartphone RTK×AR technology is rapidly becoming a powerful tool for on-site DX across surveying and construction management, not limited to pile-driving guidance.

Conclusion: A New Era of Simple Surveying Enabled by LRTK

The smartphone surveying tool LRTK, which fuses RTK positioning and AR, is accelerating on-site DX in ways that overturn conventional wisdom. Anyone can now handle centimeter-level position information easily and overlay 3D design data onto the real world—what was a dream a few years ago is now reality. This new approach of “simple surveying” enabled by LRTK opens the door for anyone on site, not just specialists like surveyors, to use high-precision surveying in everyday work.

AR×RTK fusion technology is becoming the new standard in construction management and surveying, including pile-driving guidance. Actively adopting digital tools rather than clinging to traditional methods will be key to maintaining competitiveness in the construction industry. By using smartphone surveying solutions such as the LRTK series, which are compatible with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative, you can achieve smart site operations that balance accuracy and efficiency. The future of on-site DX has already begun—take this opportunity to introduce next-generation solutions on your site and experience the innovative construction management that AR×RTK delivers.

FAQ

Q1. How accurate is RTK surveying? A. General RTK-GNSS surveying can provide planar positioning errors of a few centimeters under good conditions, and vertical accuracy on the order of a few centimeters to at most a few tens of centimeters. Even smartphone-based RTK positioning can be expected to achieve accuracy comparable to dedicated surveying instruments when appropriate correction information is used. In practice, LRTK often achieves standalone positioning errors of about 1-2 cm (0.4-0.8 in), and averaging data over a certain period can yield sub-1 cm (<1 cm (<0.4 in)) accuracy in some cases. However, accuracy varies with satellite geometry and signal conditions, so for critical measurements it is safest to confirm a stable fixed solution (Fix) before proceeding.

Q2. Is RTK surveying possible in environments where satellite reception is difficult, such as near tall buildings or trees? A. Poor satellite reception can make it difficult to maintain RTK accuracy and keep a fixed solution. In urban areas surrounded by high-rise buildings or in forests, satellite signals can be blocked or reflected, causing unstable positioning. In such environments, multi-GNSS (multiple satellite constellations) and multi-band receivers can mitigate accuracy degradation to some extent by increasing the number of usable satellites. Another approach is to perform initial positioning in a temporarily open area, then continue work using the smartphone’s inertial sensors or AR markers to supplement position. If satellites cannot be captured at all, RTK surveying may be inapplicable, and switching to traditional total-station methods may be necessary.

Q3. Does LRTK support Michibiki’s CLAS service? A. Yes. LRTK offers receiver models that support CLAS, the centimeter-class positioning augmentation service provided by Japan’s quasi-zenith satellite “Michibiki.” With a CLAS-compatible model, you can achieve centimeter-level positioning using correction signals broadcast directly from Michibiki without relying on the Geospatial Information Authority’s reference station network or the Internet. This capability is valuable because, even outside mobile coverage in mountainous or offshore areas, as long as Michibiki signals reach the sky you can maintain high-precision positioning. Note that CLAS service areas are basically limited to Japan.

Q4. What should be done in environments where GNSS signals are completely unavailable, such as inside tunnels or buildings? A. Unfortunately, RTK positioning cannot be performed where satellite radio waves are completely blocked. For tunnel work or underground floors, it’s necessary to use alternative technologies. Examples include installing reference transmitters inside tunnels and using short-range radio ranging systems, self-positioning with IMUs (inertial measurement units), and SLAM techniques based on image analysis. LRTK is a GNSS-based tool and is most effective outdoors where satellites can be received. However, in some cases you can perform baseline alignment at a location where satellites are temporarily receivable (e.g., tunnel entrance or building rooftop) and then conduct short-duration work using AR markers or known ground points to maintain relative position. It’s important to combine RTK with other methods as the situation requires.

Q5. How does site work change before and after introducing LRTK? A. Before LRTK adoption, surveying and as-built verification often required requesting specialist departments or external surveyors and waiting for results. Matching planned drawings with actual site conditions often relied on visual estimates and manual calculations, leaving room for rework and mistakes. After adoption, site staff can perform positioning and measurement on the spot and immediately check and share results via AR, significantly changing workflow. Real-time construction management improves decision speed, and any mistakes can be detected and corrected early. Tasks that used to require 2–3 people can now be done by one person, giving more flexibility in personnel planning. In short, LRTK reduces both waiting time and rework, allowing the entire site to operate more efficiently.

Q6. Are durability and battery life of smartphones a concern on site? A. In many cases, smartphone durability and battery life are adequate for site use. Recent smartphones often feature dust and water resistance and can operate in dusty or rainy conditions. Using rugged cases and screen protectors reduces the risk of damage from normal site activities. Regarding battery life, since the GNSS receiver (LRTK device) often has a built-in battery, the load on the smartphone itself is reduced, making all-day operation feasible under normal use. Carrying a spare mobile battery provides additional assurance for long continuous operation.

Q7. If we want to advance on-site DX, where should we start? A. Start by reviewing your current workflows and identifying tasks that consume significant time or effort. If surveying or pile-driving is problematic, pilot smartphone surveying or other digital technologies in those areas to validate their effectiveness. Introduce solutions on a small scale or for select tasks, collect feedback from site staff, and gradually expand the scope. Gaining understanding from management and site personnel is also important—share cost-benefit analyses and success stories from other companies to build internal consensus. Referencing i-Construction initiatives and available subsidies from the Ministry of Land, Infrastructure, Transport and Tourism can help justify adoption. Smartphone surveying solutions like LRTK are intuitive and require little specialized training, facilitating on-site adoption. Begin digitalization within your means, accumulate successful experiences, and your on-site DX will steadily progress. We encourage you to give it a try.