Smartizing Stake Driving Guidance with High-Precision GNSS and AR: Boosting Efficiency and Greatly Reducing On-Site Burden

Table of contents

• Challenges of traditional stake driving work

• Smartizing stake driving guidance with GNSS and AR

• Specific procedure for smart stake driving guidance

• Benefits of introducing smart stake driving guidance

• Simple surveying with LRTK

• Frequently asked questions

Challenges of traditional stake driving work

On civil engineering and construction sites, staking operations to place piles at precise locations based on design drawings and marking operations (setting out) to indicate column positions and other structure points on site are indispensable. Based on the numeric coordinates on drawings, it is necessary to set out positions on site with no error of even a few centimeters (a few inches), but traditional stake positioning 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 determine each stake position one by one by measuring distances and angles from control points. Even to indicate a single stake location requires multiple stages of measurement and marking, and when installing dozens of stakes over a wide site, the layout work alone can often take more than a full day.

Moreover, manual surveying and marking work carries the risk of human error. Small misreads or recording mistakes can lead to position shifts, potentially causing construction errors or rework in later stages. For example, if the reference setting is inaccurate, it may be discovered after staking that “the position doesn’t match,” requiring re-driving stakes or correcting structures. Forcing surveys on steep slopes or unstable scaffolding can endanger workers, and marking stake positions in areas where heavy machinery is operating increases the risk of contact accidents between equipment and personnel. There are also physical constraints such as being unable to secure line-of-sight for surveying instruments in sites with many visual obstructions, or the difficulty of long-distance setting out in narrow urban lots. In this way, traditional stake driving work has faced challenges of labor and time demands, precision control, and safety assurance.

In addition, the construction industry as a whole is increasingly affected by labor shortages and aging skilled workers, making it difficult to maintain traditional methods that rely on experienced personnel. The push for digital transformation (DX) on sites is partly driven by these human resource issues.

Smartizing stake driving guidance with GNSS and AR

One promising approach to solving these issues is “smart stake driving guidance,” which combines high-precision GNSS and AR (augmented reality). GNSS (global navigation satellite systems) refers to satellite positioning including GPS, and using methods such as RTK (real-time kinematic) can dramatically reduce positioning errors. Standard smartphone GPS can have errors of several meters, but RTK can reduce that error to on the order of a few centimeters (a few inches) by using correction data from base stations or augmentation satellites. In Japan, high-precision positioning services (CLAS) provided by the quasi-zenith satellite system “Michibiki” are being rolled out, and environments where centimeter-level positioning (cm level accuracy (half-inch accuracy)) can be used without installing dedicated base stations are becoming available. Recently, small RTK-capable GNSS receivers that attach to smartphones have appeared, allowing anyone’s smartphone to quickly turn into a high-precision surveying device.

AR technology overlays digital information on camera images from smartphones or tablets. For example, showing a virtual arrow or marker in the camera view of the real world can directly indicate “this is where the stake should be driven” on the screen. In other words, by linking high-precision GNSS-derived current position information with design-based stake coordinate data, the worker’s smartphone can provide navigation to the stake point. By following arrows and numeric guides on the phone screen, the user is guided to the target location, and when the destination is reached, a virtual stake appears precisely on the camera image. This “construction-site car navigation” system allows even inexperienced workers to intuitively identify exact points. Stake setting that previously required two or more people to extend a tape measure has evolved into a next-generation method that can be completed by one person holding a smartphone.

Actual sites that adopted GNSS × AR stake guidance reported that “the time required for stake layout was dramatically reduced, and stake re-drives and later-stage corrections mostly disappeared.” In one evaluation, replacing traditional optical surveying for stake layout with AR navigation reduced work time to about one-sixth, demonstrating substantially better performance than conventional methods in both precision and efficiency. The fusion of high-precision GNSS and AR has brought stake layout work to a revolutionary stage where efficiency, labor savings, and high precision advance simultaneously.

Specific procedure for smart stake driving guidance

Now let’s look at the basic steps of how smart stake driving guidance using high-precision GNSS and a smartphone is actually carried out.

1. Preparing design data: First, prepare the coordinate data of stake positions determined during the construction planning phase. Import a list of stake coordinates (latitude/longitude or planar coordinates) obtained from design drawings or CAD into a surveying app for smartphones so that points to be guided can be called up immediately on site. With cloud-enabled systems, design data uploaded from a PC in advance can be synchronized with on-site smartphones.

2. Setting up GNSS device and positioning: On arrival at the site, attach a small RTK-GNSS receiver (high-precision GNSS unit) to the smartphone and power it on. The phone and receiver connect wirelessly via Bluetooth, and satellite acquisition and RTK initialization complete in a few tens of seconds. If using a network RTK service, ensure the phone can receive correction information via a communication environment (mobile network, etc.) and confirm positioning has reached centimeter-level accuracy (cm level accuracy (half-inch accuracy)). Once ready, the smartphone is able to measure high-precision current position in real time, providing accuracy comparable to conventional surveying instruments in a palm-sized device.

3. Guidance to stake position: When you select the stake number or point to be guided in the surveying app, the direction and distance to the target are displayed on the screen. For example, if instructed “a target point 6.3 m (20.7 ft) to the northeast,” hold the smartphone and proceed 6.3 m (20.7 ft) to the northeast. An on-screen arrow indicates heading, and the distance display shrinks as you approach, showing “remaining 50 cm (19.7 in)”, “remaining 10 cm (3.9 in)”, and so on. When you arrive at the target coordinate, the distance display becomes 0 m (0 ft), and the phone notifies you, “You have arrived at the destination!” Looking through the camera, you will see a virtual stake marker (AR stake) standing on the ground without offset. The worker marks that indicated position and drives the stake according to the plan. Even on large sites, the digital arrow and AR stake ensure there is no worry about missing the intended point.

4. Saving and sharing construction records: After driving a stake, take a photo with the smartphone camera on the spot to record it. Photos are automatically tagged with GNSS-derived coordinates and uploaded to the cloud. There is no need to transfer data by USB back at the office; completion data for stake driving can be shared immediately from the site. With digital records of “which stake was driven where,” creating inspection or reporting documents later is streamlined. Having photos with location information enables objective evidence-based reporting to clients and quality assurance.

As described above, using a stake guidance system that combines a smartphone and GNSS makes it possible for people without surveying expertise to achieve accurate stake layout simply by following on-screen instructions. There is no need to pull tape measures or compare drawings on each task; surveying, recording, and position guidance on site can be completed with a single smartphone, which is a major innovation.

Benefits of introducing smart stake driving guidance

Introducing such smart stake driving guidance on site brings various benefits over traditional methods in terms of accuracy, efficiency, and safety. The main effects are summarized below.

• Improved accuracy: Centimeter-level guidance via RTK-GNSS almost eliminates stake position deviations. Precise construction according to design drawings becomes possible, preventing assembly failures or repair work caused by stake center misalignment. This enables safe delegation of stake driving even in projects requiring very high accuracy, such as high-rise buildings and bridges.

• Dramatic improvement in work efficiency: Time spent on surveying and layout is greatly reduced. Since positioning that used to require multiple people can be completed by one person, there is no need to adjust personnel assignments. In some cases, stake layout that used to take half a day can be completed in just a few tens of minutes, so productivity improves significantly. The labor savings also translate to reduced personnel costs.

• Labor reduction and skill leveling: Because workers only need to follow on-screen guidance, stake layout can be performed without a skilled surveyor. Tasks that previously relied on specialists can be handled by general workers, making adoption easier even on sites suffering from labor shortages. With only a smartphone and a small receiver required, initial costs can be kept low, making operations such as one device per person on site realistic. This contributes to standardizing skills across the site and reduces dependency on specific individuals.

• Improved safety: There is no need to force workers into hazardous locations for stake layout. Using AR displays, positions can be confirmed from safe locations for unstable slopes or otherwise inaccessible spots by placing virtual markers remotely. Reducing surveying near heavy equipment lowers the risk of contact accidents, and workers’ physical burden is reduced so they can work more safely and with greater composure.

• Quality control and data recording: Digital positioning data and photo records are automatically stored, making post-construction quality inspections and reporting easier. A record of which stake was placed at which coordinates is useful for later position checks or additional work. Presenting objective evidence to clients and regulatory authorities enables highly reliable quality management.

• Promoting on-site DX with multiple uses: Once this smartphone surveying system is introduced, it can be leveraged for many purposes beyond stake driving. In addition to setting out, it can be applied to as-built measurements (measuring post-construction shapes), locating buried utilities, and AR projection of 3D design data on site. For example, you can scan surrounding terrain with a smartphone’s LiDAR between staking tasks and save it as a 3D point cloud with accurate RTK position information, overlaying it with the design model on the spot to check deviations. Digitizing work that relied on paper and intuition dramatically improves on-site productivity and the quality of information sharing.

Given these advantages, high-precision GNSS + AR stake guidance is expected to increasingly become the on-site standard. This aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s promotion of i-Construction (construction DX using ICT), and many sites have already begun adopting it. Sites that feel limited by conventional methods can evolve to the next stage by actively introducing digital technologies.

Simple surveying with LRTK

As an example of a solution that lets you immediately implement stake guidance using high-precision GNSS and a smartphone, we introduce LRTK. LRTK is an all-in-one site support tool consisting of a small RTK-GNSS receiver, a dedicated app, and cloud services. By simply attaching a receiver of about 150 g to a smartphone, a palm-sized smartphone instantly becomes a surveying instrument capable of centimeter-level positioning (cm level accuracy (half-inch accuracy)). The captured current position data synchronizes with design coordinates in the cloud and guidance displays in real time on the on-site smartphone screen, allowing surveying, positioning, and recording to be completed with a single smartphone.

Key features of LRTK include the ability to position stakes and set-outs to within a few centimeters using high-precision positioning, visualizing virtual stake markers with AR, and a coordinate navigation function that provides real-time direction and remaining distance simply by calling up registered stake data from the cloud. Remote guidance is also possible, enabling safe position confirmation from a distance in places where physically installing survey markers is dangerous. Tasks that traditionally required heavy, expensive equipment and training can be easily accomplished with a familiar smartphone using LRTK. The device itself is an integrated unit with a dustproof/waterproof design and built-in antenna and battery, so it can be used reliably even in harsh outdoor conditions. Bluetooth connectivity allows cable-free operation, so it won’t get in the way when walking around the site.

By using LRTK, stake driving work that relied on paper drawings and craftsmanship can be digitized to create a site where anyone can perform accurate layout. This is truly an innovative solution that makes “stake guidance anyone can do” a reality. The LRTK series achieves reduced work time and improved productivity through high-precision positioning, contributing to DX promotion in the construction industry. If you currently face issues with stake layout accuracy or work efficiency, introducing smart surveying technologies like LRTK offers a chance to greatly reduce on-site burden. For details, please visit the official LRTK website to check the latest information and case studies.

Frequently asked questions

Q. What equipment and preparations are required to use smart stake driving guidance? A. Basically, an AR-capable smartphone (or tablet) and a GNSS receiver capable of centimeter-level positioning are required. Specifically, attach an RTK-capable high-precision GNSS unit to the phone and prepare a communication environment (mobile network, etc.) to receive correction information. In outdoor environments with open sky, combining these enables smooth stake guidance on site.

Q. Can accurate stake layout be done with only the smartphone’s built-in GPS? A. Unfortunately, general smartphone GPS (standalone positioning) typically has errors of several meters, so it is unsuitable for precise stake layout. Achieving centimeter accuracy requires RTK-GNSS corrections; only with dedicated high-precision GNSS devices or augmentation services from satellites or networks can AR guidance demonstrate its full value. For example, using a solution like LRTK allows ordinary smartphones to perform high-precision positioning with confidence.

Q. Can less experienced workers handle it? A. Yes. Systems are designed for intuitive operation, so people without specialized surveying knowledge can use them. Workers simply follow the guides displayed on the smartphone screen for movement and position confirmation, without complex calculations or settings. Once basic operations are learned, non-experts can fully utilize the system on site. In practice, there are reports of young staff performing stake layout that previously required surveyors without issue.

Q. Do weather or surrounding conditions affect accuracy or operations? A. In principle, the system can be used stably regardless of weather so long as the environment offers a view of the sky outdoors. However, GNSS positioning requires receiving satellite signals, so accuracy deteriorates in locations surrounded by tall buildings, inside tunnels, or indoors. If using network RTK corrections, you also need to be within a communication area. In mountainous regions with unstable communications, services that receive augmentation signals directly from satellites (for example, Japan’s Michibiki CLAS augmentation) can be used. AR display is possible at night, but minimum lighting is required for the smartphone camera to capture the real scene.

Q. Can this technology be used for purposes other than stake driving? A. Yes. Its applications extend beyond stake driving. On building and civil engineering sites, AR coordinate navigation can be applied to marking foundation and anchor positions, machine installation positioning, post-construction as-built verification, and more. It can visualize the positions of buried pipes and cables with AR to assist safe excavation. Additionally, 3D design models and drawing data can be overlaid on site images to intuitively share the completed image. In short, GNSS × AR guidance is powerful in any scenario where “accurate position needs to be indicated on site.”