Table of Contents

• Traditional pile-driving work and its challenges

• What is an AR pile-driving guidance app?

• Main features of LRTK’s AR pile-driving guidance app

• Benefits the AR pile-driving guidance app brings to the site

• Use of LRTK for simple surveying

• FAQ

Pile-driving work on construction sites (positioning and installing piles based on design drawings) is a critical process that greatly affects the overall accuracy of structures. However, traditional pile-positioning has been labor- and time-intensive and relied heavily on experienced surveyors. Enter LRTK’s AR pile-driving guidance app. By combining a smartphone with high-precision positioning technology, a new era is opening in which anyone can easily drive piles at the points specified in the drawings. This digital technology, which overturns conventional wisdom, has the potential to dramatically improve on-site productivity. This article explains the problems of conventional methods and the innovations introduced by the AR guidance app, and presents the efficiency benefits this technology brings to the field.

Traditional pile-driving work and its challenges

Conventional pile-positioning work has centered on manual methods using surveying instruments such as transits and auto levels together with tape measures. As a result, various issues arise in terms of ensuring accuracy and work efficiency. The main problems include:

• Large personnel and procedural burden: Pile layout typically requires two or more people; the surveying instrument must be set up and measured, and an assistant measures distances with a tape and marks points, following cumbersome procedures. Consequently, positioning a single point took time. On large sites, completing all pile layouts could take several days, becoming a bottleneck for the entire operation.

• Dependence on skilled technicians: Operating surveying instruments and deriving coordinates from drawings requires experience, and accurate pile positioning was difficult without a seasoned surveyor. Newcomers were prone to mistakes, and technician shortages and generational change became issues. Because advanced skills were required, training personnel also took considerable time.

• Site environment constraints: Optical surveying with total stations requires line of sight between the instrument and target points. In sites with many obstacles or during night work, visual guidance has limits, and conventional methods can be difficult to use. Extra work such as removing obstacles or erecting temporary fixtures for surveying is sometimes necessary.

• Risk of human error: Human mistakes such as misreading a tape measure or misplacing a mark were common. Incorrect pile positions lead to rework in later stages with “positions not matching,” causing schedule delays and additional costs. Even a few centimeters of deviation can affect the safety of the entire structure, so there is immense pressure to avoid mistakes in pile positioning. A single error can delay the whole operation, so the site is always under tension.

To address these issues, specialized equipment aimed at labor-saving and error reduction has long been developed. However, high-performance total stations and automated pile-driving navigation systems are expensive and require time to learn, making them difficult to introduce on small- to medium-sized sites or by beginners. A technology that answers the on-site demand for “something easier that allows anyone to accurately position piles” was eagerly awaited.

What is an AR pile-driving guidance app?

The latest AR pile-driving guidance app is a system that combines a smartphone with high-precision GNSS (Global Navigation Satellite System) technology to intuitively navigate workers to pile-driving positions. The key technology is RTK (Real Time Kinematic), a high-precision positioning technique that corrects satellite positioning errors in real time to enable positioning within an error of a few centimeters (a few cm (a few in)). LRTK is a small RTK-GNSS receiver that can be attached to a smartphone; with this device and a dedicated app, the smartphone itself becomes a surveying instrument with centimeter-level accuracy. The LRTK unit weighs approximately 165 g and is pocket-sized, about 1 cm (0.4 in) thick, and its internal battery allows about 6 hours of continuous positioning. It also supports high-precision augmentation signals (CLAS) provided by Japan’s quasi-zenith satellite “Michibiki,” enabling centimeter-level positioning even outside cellular coverage.

The app allows you to pre-load coordinate data from design drawings (the positions where piles should be driven) via the cloud and select the target coordinate on site. The smartphone screen then continuously displays an arrow indicating the direction to the target point and the distance from the current location; the worker simply follows that guidance to be led to the precise position. Moreover, AR (augmented reality) displays overlay virtual markers and arrows on the smartphone camera view to visually indicate the target point in the real scenery. For example, a pin can appear on the ground in the camera view at the design-specified location, so even those unfamiliar with surveying can intuitively understand, “This is where the pile should be driven.” As you approach the target, the distance display gradually decreases, and when it is almost zero, it indicates that the design coordinates match exactly. Mark the spot and drive the pile to complete the positioning.

The app’s operation is also simple. For example, pile layout work proceeds as follows:

• Select the target pile coordinate in the app and tap “Start guidance”

• Move toward the target using the arrow and distance displayed on the screen

• When the distance display is near zero, install and mark the pile at that spot

• Register “Installation complete” in the app to finish the task

Using the AR pile-driving guidance app, pile layout that previously required multiple people can be done by one person without hesitation. Since you only follow the navigation on your smartphone, advanced surveying skills are unnecessary. It feels exactly like following a game marker, so anyone can accurately reach the pile-driving point. Next, we’ll look at the specific features of LRTK’s AR pile-driving guidance app.

Main features of LRTK’s AR pile-driving guidance app

• Centimeter-level high-precision positioning: RTK-GNSS enables both horizontal and vertical positioning with errors on the order of a few cm (a few in). By simply attaching the small LRTK device to a smartphone, you can achieve field accuracy comparable to conventional large surveying instruments. Conventional smartphone GPS had errors of several m (several ft), but this system reduces that to a few cm (a few in). Vertical accuracy is also excellent, so it can be applied to tasks such as measuring top-of-foundation elevations.

• Coordinate navigation function: The app displays a real-time directional arrow and distance to the set target coordinate to guide the worker. Like a car navigation system, it leads you to the target point so you can find the pile location without surveying expertise. The difference between your current location and the target coordinate can also be checked numerically, so you can grasp the magnitude of any offset. As you approach the target, the distance display approaches zero, ensuring arrival at the designated position.

• Intuitive AR guidance: Virtual arrows and pins are displayed on the smartphone camera view to visually indicate the precise point where the pile should be driven. The AR display, based on high-precision position data, has virtually no positional offset, so design points are visualized directly on the ground as markers. Because markers are always shown on the screen in AR, there is no worry about losing ground markings and searching for them. Without relying on intuition or experience, you simply move according to the visual instructions to reach the exact location.

• Easy one-person operation: Whereas pile layout traditionally required multiple people, the app’s guidance allows the task to be completed by one person. There is no need to carry heavy equipment and set it up, significantly reducing the effort of walking around the site. Even on sites short of personnel, pile-driving work can proceed without issue, directly reducing manpower and shortening work time. In addition, because you can always check the offset between your position and the target coordinate on the screen, you won’t worry “Is this the right position?” and can work with confidence.

• Cloud integration and data management: Design coordinate data can be uploaded to the app from the cloud in advance and easily recalled on site for guidance. Survey data collected during work can also be shared to the cloud immediately, making it easy to confirm pile-driving results from the office. The app’s positioning photo feature automatically records coordinate information and azimuth on photos taken at pile locations, allowing instant use as reporting material. This eliminates the need to write positions on paper drawings or organize photos, dramatically improving the efficiency of record-keeping.

Benefits the AR pile-driving guidance app brings to the site

Efficiency and time savings: AR guidance allows pile positioning that used to require two or more people to be completed by one person, and simplified surveying procedures significantly reduce work time. The need to measure repeatedly or reset equipment is eliminated, enabling many points to be positioned in a short time. For example, work that formerly took half a day for pile driving could be completed in a few hours, producing substantial efficiency gains. This contributes to shorter overall schedules and reduced labor costs.

Prevention of surveying mistakes and quality improvement: Following digital navigation greatly reduces human error. Misreading tape measures or incorrect position instructions disappear, enabling correct pile installation on the first try. Previously, even a few centimeters of deviation could affect the safety of the entire structure, but this system minimizes that risk. Improved construction accuracy prevents losses from having to redo work later. Ensuring pile-position accuracy leads to overall improvements in quality and safety of structures.

Addressing labor shortages: Even without veteran surveyors on site, anyone can accurately drive piles without hesitation. Because advanced skills are not required, newcomers can become productive team members, improving a situation that previously relied heavily on experts. Increased flexibility in personnel deployment allows sites to operate with smaller teams, making this a promising solution to chronic labor shortages. It also supports generational transition, enabling young teams to carry out surveying tasks. Veterans can concentrate on more advanced duties, boosting productivity across the site.

Cost reduction: The aforementioned labor savings and reduction in rework contribute to cost reductions across the project. Shorter work times compress labor costs, and mistakes that would cause material waste or rework expenses are prevented. The efficiency gains free up resources for other tasks, improving overall project productivity and achieving a cost-effective site operation.

Promoting on-site DX: Introducing the AR pile-driving guidance app accelerates the digitalization (DX) of surveying and construction. Tasks that relied on paper drawings and manual records are unified as data. With cloud-based information sharing, reporting and confirmations between the site and office become real-time, streamlining workflows. Standardizing previously person-dependent positioning tasks means anyone can achieve the same accuracy, which is a major advantage. This aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s push for i-Construction (ICT construction), and the app is expected to spread further as part of on-site DX.

Use of LRTK for simple surveying

The LRTK system is useful not only for pile-driving guidance but also for a wide range of on-site simple surveying tasks. The ability to perform various surveying and recording tasks easily with just a smartphone is a major attraction. Possible uses include:

• Single-point surveying: With an LRTK-attached smartphone, you can measure the coordinates of any point on the spot with high accuracy. For example, you can remeasure benchmark points or boundary stakes alone, or easily record coordinates for key points on site. If attached to a monopod (pole) and a height offset is set as needed, you can also measure elevations with cm level accuracy (half-inch accuracy).

• Photo + location recording: As mentioned earlier, the positioning photo feature automatically attaches accurate coordinates and the camera’s orientation to photos taken with the smartphone. This is useful not only for recording completed pile locations but also for clearly recording the locations of defects found during inspections for later tracking. Recorded photos are synchronized to the cloud immediately and can be shared instantly with remote managers.

• 3D scanning for as-built capture: Using a smartphone’s LiDAR sensor or camera, you can record the site as a point cloud (3D data). Because high-precision position information from LRTK is added, point cloud data acquired with a smartphone can be handled in true measured scale. You can quickly record foundations and ground irregularities in 3D and use the data for earthwork volume calculations, making applications that formerly required dedicated laser scanners or drones possible with a palm-sized device. Acquired point cloud data can be shared on the cloud and easily viewed and used by stakeholders on a PC.

In this way, with LRTK you can complete a series of tasks—from pile-driving to surveying and documentation—using just a smartphone. As an innovative system that overturns conventional wisdom, it will be a powerful tool to drive on-site digitalization and efficiency. In the near future, this technology may become an indispensable standard tool in surveying and construction sites. Consider adopting this new surveying method using the AR pile-driving guidance app and experience its effects firsthand.

FAQ

Q: What do I need to use the AR pile-driving guidance app?

A: Basically, an iOS device such as an iPhone and the dedicated high-precision GNSS receiver “LRTK” device are required. Install the LRTK app from the App Store and attach the LRTK unit to your smartphone to get started. High-precision positioning requires reception of correction information via the Internet (or augmentation signals from the Michibiki satellite), but this is usually handled automatically via the phone’s connection. (Currently, Android devices are not supported.)

Q: What level of positioning accuracy can be achieved?

A: Under good positioning conditions, you can generally obtain high accuracy of about 2 cm (0.8 in) horizontally and several cm (a few in) vertically (accuracy may degrade where satellite signals are blocked). GNSS reception conditions affect accuracy, but the system provides sufficient precision for typical pile-driving and as-built management.

Q: What kinds of sites and uses are suitable?

A: It can be used for all kinds of pile-driving tasks such as setting reference piles for civil engineering works and position layout on building sites. It is effective even on sites with complex terrain where line of sight is difficult, as long as GNSS reception is available. Beyond pile-driving, it is useful in a variety of surveying scenarios such as ground surveys, boundary-point checks, and positional records during equipment inspections.

Q: Can people without surveying experience use it?

A: Yes—thanks to the intuitive on-screen guidance, even beginners can handle it easily. You only need to move according to the arrows and AR markers displayed in the app, so specialized surveying knowledge or complicated instrument operation is unnecessary. With basic operation training in advance, non-specialists can carry out pile-layout work on site.

Q: How do I import design data and use survey results?

A: The LRTK app supports import/export of various coordinate data. If you upload a coordinate list (CSV format, LandXML format, the Geospatial Information Authority of Japan’s standard sima format, etc.) to the cloud in advance, you can select that data on site for pile-driving guidance. Conversely, coordinates of points measured on site are saved and shared via the cloud and can be exported as CSV for reflection in CAD drawings as needed. This enables smooth data linkage without carrying paper drawings or USB memory.

Q: Can it be used in rain or bad weather?

A: The LRTK unit is water-resistant, so it operates fine in light rain. GNSS surveying is generally less affected by weather, so accuracy is largely maintained in rainy conditions. At night, AR displays are visible if you sufficiently illuminate the ground with a headlamp or work light, so 24-hour operations are possible when needed. However, stop work for safety during heavy rain or thunderstorms. Also note that positioning may become unstable under extreme weather conditions such as typhoons.