Dramatic Improvements in Piling Guidance Accuracy and Safety: Toward Zero Human Error with GNSS + AR

Table of Contents

• Innovation in piling guidance enabled by GNSS and AR

• Problems and risks inherent in conventional piling work

• Automation and high-precision piling guidance with GNSS + AR

• Toward zero human error: dramatic improvements in safety and efficiency

• Simple surveying procedure with LRTK

• FAQ

Innovation in piling guidance enabled by GNSS and AR

In recent years, cutting-edge technology that combines GNSS (Global Navigation Satellite Systems) and AR (Augmented Reality) has brought revolutionary changes to piling guidance methods on construction sites. Until now, tasks such as surveying and marking pile positions required heavy surveying equipment and multiple personnel, consuming significant time and effort. However, by leveraging high-precision GNSS positioning (centimeter-level methods such as RTK) on smartphones and overlaying digital design information onto real-world views via AR, the situation is rapidly changing. Simply attaching a compact high-precision GNSS receiver to a smartphone makes it possible to guide pile positions that previously required specialized equipment and skilled technicians, spawning a new workflow called "smartphone surveying." The fusion of GNSS and AR allows designers’ data to be visualized intuitively on site while providing accurate position guidance in real time, helping to address labor shortages and dramatically improve work efficiency and accuracy. In addition, the large reduction in work errors enhances overall safety, making the goal of zero human error increasingly attainable.

Problems and risks inherent in conventional piling work

Traditional methods for marking pile locations involved many inefficiencies and risks. To start, placing piles according to drawings typically required mounting specialized surveying instruments like total stations on tripods and a two-person team of a surveyor and an assistant to determine positions. Even installing a single pile in the correct location entailed complex steps such as measuring distances from reference points with tape measures and having staff adjust positions under the surveyor’s instructions. When installing many piles across a large site, surveying and piling alone could easily take more than a full day. Such manual, labor-intensive conventional methods significantly reduced overall site efficiency.

Moreover, relying on analog methods in conventional piling work carried a high risk of human error, leaving doubts about accuracy. For example, misreading or recording surveying numbers can lead to incorrect pile positions. Even small measurement errors that shift pile placement can cause rework (reinstallation) or downstream construction mistakes. Misaligned foundation piles compromise the quality and safety of structures, and if positional errors are discovered after construction, extensive repair work may be required. Also, inexpensive handheld GPS units can have positioning errors of 5-10 m (16.4-32.8 ft), making them unsuitable for precise piling. Consequently, projects had to rely on costly high-precision surveying equipment and experienced technicians, raising the cost barrier.

From a safety perspective, conventional piling work also had room for improvement. Operating heavy machinery while multiple workers stretch tape measures and give signals inevitably introduces risks of communication errors and unexpected movements leading to accidents. In particular, when workers guide machinery close to the equipment to indicate survey points, there is a significant hazard if survey staff enter the machine’s blind spots. In short, conventional methods faced challenges across efficiency, accuracy, and safety.

Automation and high-precision piling guidance with GNSS + AR

The trump card for resolving these issues is the automation of piling guidance using GNSS positioning and AR display. Systems composed of a smartphone fitted with a high-precision GNSS receiver and a dedicated app (for example, solutions like LRTK) can load coordinate data of pile positions defined in construction drawings and display the remaining distance and direction to the target point in real time on site. The smartphone screen can continuously show instructions like “East ○○ cm / North ○○ cm to the target point,” enabling workers to reach the correct position by simply taking a few steps as instructed. Tasks that once required several people and tape measures can now be completed by one person with a smartphone.

AR technology also enables “AR piling guidance,” where markers or virtual piles are overlaid on the live camera feed. Because the design pile positions are marked on the scene captured by the smartphone camera, workers can intuitively identify the point where “the pile should be driven.” Even without advanced surveying skills, workers can follow visual guides to determine pile locations, which is expected to greatly reduce measurement errors and rework. Sites that have implemented GNSS + AR systems have reported outcomes such as “dramatic reductions in the time required for piling work” and “improved pile installation accuracy with almost no corrective work in later stages.” By combining positioning accuracy with visual guidance, automation makes piling work dramatically more efficient and high-precision, bringing human-caused errors ever closer to zero.

Toward zero human error: dramatic improvements in safety and efficiency

Adopting the latest GNSS + AR technology on site makes it realistic to reduce human error to near zero. Cases where smartphone surveying systems were introduced have shown remarkable gains in efficiency and error reduction. For example, one municipality quickly adopted smartphone + GNSS surveying for disaster recovery works and succeeded in speeding up recovery and reducing costs compared with conventional methods. Being able to survey disaster-affected areas rapidly with limited personnel significantly shortened the timeline from recovery planning to construction start. This technology, developed by a university-launched venture, has been featured in the media as a leading-edge solution and highlights digital transformation (DX) in construction.

What concrete benefits can be expected from deploying GNSS + AR piling guidance on site? Key points are:

• Shorter work time: Time spent on surveying and marking pile positions is greatly reduced. There are reports of foundation marking work that used to take days being completed in hours. Even when measuring many points over large areas, a single person can sequentially perform guidance and measurement, directly shortening project schedules.

• Reduced personnel required: Surveying and marking tasks that previously took two to three people can be completed by one person, enabling work to proceed smoothly even on sites chronically short of labor. Because young or inexperienced employees can follow smartphone instructions to achieve high-precision location marking without relying on veteran surveyors, this helps mitigate skills shortages.

• Reduced human error: Accurate coordinates from GNSS and visual guidance from AR minimize opportunities for human mistakes, drastically lowering rates of errors such as misplaced piles or missed measurements. Being able to set a pile correctly on the first try eliminates rework and contributes to early detection of quality issues. As a result, overall project safety and quality improve. Eliminating unnecessary mistakes and redo work also reduces workers’ mental burden and contributes greatly to on-site safety.

By introducing smartphone surveying systems that utilize GNSS + AR, significant improvements can be achieved in time, personnel, and accuracy. Enhanced work efficiency and quality, combined with virtually zero human error, enable safe and reliable construction management.

Simple surveying procedure with LRTK

So how is surveying and piling guidance actually performed using a smartphone and GNSS? Here is an example workflow for simple surveying using the GNSS + AR system LRTK. LRTK is a solution in which a compact high-precision GNSS device is attached to a smartphone and surveying/guidance is performed via a dedicated app. When installing piles or setting reference points on site, the work procedure becomes very simple.

• Device attachment and start of positioning: Attach the high-precision GNSS receiver (LRTK unit) to the smartphone and power it on. When you launch the dedicated app, high-precision positioning using the RTK method begins in about several tens of seconds, and your current position is displayed on the smartphone screen with centimeter-level accuracy (half-inch accuracy).

• Preparation of survey data: Load coordinate data for the target points where piling or surveying is required into the app. A prepared list of coordinates from design drawings or CAD data can be uploaded via the cloud and synchronized to the smartphone on site.

• Coordinate navigation for position guidance: Use the app’s “coordinate nav” feature to select the target point and start guidance. The direction and distance from your current position to the target are displayed in real time, and you move according to the guidance. If you switch to AR mode as needed, arrows and markers indicating the guidance point are overlaid on the smartphone camera feed for even more intuitive positioning.

• Arrival at point and marking: When the distance display on the smartphone reaches zero, you have arrived at the target coordinate. Drive the pile there or mark the spot with a marking pin or spray. With high-precision GNSS positioning, you can determine the point accurately in one go without needing to remeasure later.

• Coordinate photo capture: Next, take photos of the surrounding situation for records and inspections. When you use the app’s built-in camera to photograph the target, latitude, longitude, elevation, and camera orientation information for the shooting location are automatically attached to the photo data and saved to the cloud. For example, if you photograph the pile you just installed and nearby structures, you can later use those geotagged photos as as-built records in the office.

• Data sharing and utilization: The measured point coordinates and geotagged photos can be uploaded to the cloud on site. Back in the office, opening the cloud map on a PC displays the pile positions and inspection photos obtained on site plotted on a map in a list. Those data can be exported to CSV or drawing formats as needed for deliverables and reports.

As described above, by using a system that combines a smartphone and GNSS, you can carry out intuitive operation for surveying, piling guidance, and record-keeping in an integrated manner without special hassle. The power of GNSS + AR has truly transformed on-site work. Today, with a pocket-sized device and a single smartphone, anyone can achieve high-precision and safe piling guidance.

FAQ

Q. What is GNSS? How is it different from the conventional GPS? A. GNSS stands for Global Navigation Satellite Systems, a collective term for multiple satellite positioning systems including GPS. Simply put, it is a satellite network for determining one’s position. Positioning using a conventional smartphone’s built-in GPS typically has errors of about 5-10 m (16.4-32.8 ft) due to satellite signal inaccuracies, but by combining GNSS with correction technology called RTK (Real-Time Kinematic), errors can be reduced to a few centimeters (a few inches). In other words, using GNSS + RTK enables centimeter-level positioning outdoors, making it suitable for precise tasks such as piling.

Q. What does AR-based piling guidance do? A. AR-based piling guidance overlays design pile position data onto live images on a smartphone or similar screen. For example, virtual piles or markers appear on the ground in the camera view, so workers can intuitively understand “place the pile here” by looking at the screen. There is no need to remeasure dimensions from drawings on site as in conventional methods; simply placing the pile according to the on-screen guidance allows accurate pile marking even without specialized surveying skills.

Q. Will site safety really improve by introducing GNSS + AR? A. Yes, safety improves significantly. First, because fewer people are needed for tasks, the number of personnel entering hazardous areas is reduced. There are fewer situations where assistants must signal near heavy machinery, lowering the risk of contact accidents and near-misses. Eliminating rework caused by surveying errors also prevents the unsafe conditions that arise when hastily redoing tasks. Moreover, preventing pile misplacement ensures structural quality, reducing concerns about accidents due to construction defects. In these ways, GNSS + AR enhances both on-site labor safety and the structural safety of completed works.

Q. What is required to introduce GNSS + AR piling guidance? A. At minimum, a high-precision GNSS receiver and a smartphone/tablet app that works with it are required. Attach the receiver to the smartphone and receive correction data for high-precision positioning (RTK service) via the Internet to start centimeter-class positioning immediately. Preloading design data (coordinate lists or drawings) into the app allows on-site guidance to those coordinates. Solutions like LRTK bundle the receiver, app, and cloud service, enabling deployment without special equipment setup or complex configuration.

Q. Can GNSS guidance be used in mountainous areas without cellular coverage? A. Yes. In Japan, network RTK services using the Geospatial Information Authority’s reference station network are common, but there are methods for sites without mobile coverage. For example, receivers compatible with the Cabinet Office’s Quasi-Zenith Satellite System “Michibiki” CLAS (Centimeter Level Augmentation Service) can receive correction signals directly from satellites, enabling real-time high-precision positioning without Internet connectivity. Alternatively, a portable base station can be set up on site. LRTK supports such diverse correction methods, so high-precision piling guidance is possible even in remote mountains or isolated islands.

Q. Can people without specialized knowledge or certifications operate this system? A. Yes. GNSS + AR guidance systems are designed with an intuitive user interface and are easy to understand; with brief operational training, even those with little field experience can use them. Devices like LRTK were developed to overturn the notion that surveying is only for specialists and aim to be usable by anyone on site. No special qualifications are required—simply follow the app’s guided steps to perform high-precision piling guidance and surveying, so even those new to surveying can adopt the system with confidence.

Q. Can this technology be used for tasks other than piling? A. Yes. GNSS + AR positioning technology is applied in many areas beyond piling. For infrastructure maintenance and inspection, geotagged photo records clearly document “which location and which direction were photographed.” Other uses include visualizing boundary lines for land development, displaying locations of underground utilities via AR, and visualizing hazard locations for safety training. In short, GNSS + AR is powerful for any work requiring precise location. The high-precision positioning and intuitive AR display developed for piling guidance will be key to improving efficiency and safety across many future construction and surveying scenarios.