A Must-See for Surveyors! Improve On-Site Efficiency with LRTK’s AR Stake Driving Guidance App

Table of Contents

• Traditional stake driving work and its challenges

• What is an AR stake driving guidance app?

• Main features of LRTK’s AR stake driving guidance app

• Benefits the AR stake driving guidance app brings to sites

• Utilization of simple surveying with LRTK

• FAQ

Stake driving work on construction sites (positioning and installing stakes according to design drawings) is a critical process that greatly affects the overall accuracy of a structure. However, conventional stake positioning has been time-consuming and labor-intensive, and often relied on experienced surveyors. Enter LRTK’s AR stake driving guidance app. By combining a smartphone with high-precision positioning technology, a new era is opening in which anyone can easily place stakes exactly where the drawings specify. This digital innovation, which overturns previous conventions, has the potential to dramatically improve on-site productivity. This article explains the problems with conventional methods and the innovations brought by the AR guidance app, and introduces the efficiency benefits this technology provides to sites.

Traditional stake driving work and its challenges

Traditional stake positioning work centered on manual methods using surveying instruments such as transits and auto-levels together with tape measures. As a result, various challenges arose in terms of ensuring accuracy and improving work efficiency. The main problems include the following points:

• Heavy personnel and procedural burden: Stake setting typically requires two or more people. The surveying instrument must be set up and measured, while an assistant measures distances with a tape and marks locations—complicated procedures that made positioning each point time-consuming. On large sites, completing all stake placements could take several days, becoming a bottleneck for the entire operation.

• Dependence on skilled technicians: Operating surveying equipment and deriving coordinates from drawings requires experience, and accurate stake positioning was difficult without a skilled surveyor. Newcomers were prone to mistakes, and shortages of skilled personnel and generational turnover posed problems. Because advanced skills were required, training took time.

• Site environment constraints: Optical surveying with total stations requires line-of-sight between the instrument and the target point. On sites with many obstacles or for night work, visual guidance has limits, and conventional methods may be difficult to apply. Additional work such as removing obstacles or installing temporary fixtures for surveying may be necessary.

• Risk of human error: Reading tape measures incorrectly or marking the wrong position were common human errors. If a stake position is wrong, rework occurs in later processes due to “misaligned positions,” leading to schedule delays and extra costs. Even deviations of just a few centimeters can affect the safety of an entire structure, so there is immense pressure in stake positioning—mistakes can delay the whole job, forcing constant tension on site.

To address these challenges, specialized equipment aimed at labor savings and error reduction has long been developed. However, high-performance total stations and automatic stake-driving navigators are expensive and require time to master, making them difficult for small and medium-sized sites or beginners to adopt. The industry has awaited technology that answers the on-site call: “Can we make stake positioning easier so anyone can accurately set stakes?”

What is an AR stake driving guidance app?

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

The app loads design coordinate data (positions where stakes should be driven) from the cloud in advance, and the operator selects 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 position; the worker simply follows that guidance to be led to the precise location. In addition, AR (augmented reality) display overlays virtual markers and arrows onto the smartphone’s camera view to visually indicate the target point in the real scene. For example, a pin may appear on the ground in the camera view at the design-specified position, so even those unfamiliar with surveying can intuitively understand “this is where the stake should be driven.” As one approaches the target, the distance display gradually decreases, and when it nears zero it indicates that the design coordinate and the actual position coincide. Mark the spot and drive the stake to complete the positioning.

The app’s operation is also simple. For example, stake setting proceeds in roughly the following steps:

• Select the coordinate of the target stake in the app and tap “Start Guidance”

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

• When the distance display nears zero, place and mark the stake at that location

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

Using the AR stake driving guidance app, stake setting that previously required multiple people can be completed by one person without hesitation. Because you just follow the smartphone navigation, advanced surveying skills are unnecessary. It’s like following a game marker—anyone can reach the exact stake position intuitively. Next, let’s look at the specific features of LRTK’s AR stake driving guidance app.

Main features of LRTK’s AR stake driving guidance app

• Centimeter-class high-precision positioning: RTK-GNSS enables horizontal and vertical positioning with errors at the centimeter level. Simply attaching the small LRTK device to a smartphone achieves on-site accuracy comparable to conventional large surveying instruments. Ordinary smartphone GPS had errors of several meters (several ft), but this system reduces that to several centimeters (several in). Vertical accuracy is also excellent, so it can be applied to height measurements such as foundation top levels.

• Coordinate navigation function: The app displays a real-time direction arrow and distance to the set target coordinate to guide the worker. It leads you to the target like a car navigation system, so even without surveying expertise you can find the stake location without getting lost. You can also check the numeric differences between your current position and the target coordinates to understand the deviation quantitatively. As you approach the target, the distance display will approach zero, ensuring arrival at the specified position.

• Intuitive AR guidance: Virtual arrows and pins are displayed over the smartphone’s camera view to visually indicate the exact point where the stake should be driven. The AR display, based on high-precision positioning data, has minimal position offset, so design points are visualized as markers directly on the ground. Because AR markers remain visible on the screen, you won’t lose the marked ground point and have to search for it. Without relying on intuition or experience, you can reach the exact position simply by following the visual cues.

• Easy one-person operation: Stake setting, which used to require multiple people, can be completed by a single person following the app’s guidance. There is no need to carry and set up heavy equipment, and the physical effort of walking around the site is greatly reduced. Even on sites short on personnel, stake driving can proceed without disruption, directly enabling labor reduction and shorter work times. Also, because you can always check the deviation between your position and the target coordinate on screen, you can perform staking with confidence, without worrying “Is this position correct?”

• Cloud integration and data management: Design coordinate data can be uploaded from the cloud to the app in advance and easily retrieved on site for guidance. Survey data collected during work can also be shared to the cloud immediately, making it easy to verify stake results from the office. The app’s “positioned photo” feature automatically records coordinate information and orientation with photos taken at stake positions, allowing these images to be used directly as reporting materials. This eliminates the need to write positions on paper drawings or organize photos manually, drastically improving record-keeping efficiency.

Benefits the AR stake driving guidance app brings to sites

Labor savings and time reduction: With AR guidance, stake positioning that previously required two or more people can be completed by one person, and simplified surveying procedures result in a significant reduction in work time. The need for repeated measurements or resetting instruments is eliminated, allowing many points to be placed in a short time. For example, tasks that used to take half a day for stake placing may be completed in a few hours, greatly improving efficiency. Consequently, the overall project schedule can be shortened and labor costs reduced.

Prevention of surveying errors and quality improvement: Following digital navigation drastically reduces human error. Mistakes such as misreading a tape measure or miscommunication on position are eliminated, enabling accurate stake installation in one go. Small deviations of a few centimeters that could previously affect structural safety are minimized with this system. Improved construction accuracy prevents rework in later stages, contributing to overall quality and safety improvements of the structure.

Response to labor shortages: Even without veteran surveyors on site, anyone can accurately perform stake driving. Because advanced skills are not required, newcomers can contribute immediately, improving dependence on experienced staff. Greater flexibility in personnel allocation allows sites to operate with fewer people, making this a promising solution to chronic labor shortages. Teams led by younger personnel can also carry out surveying tasks, aiding generational transition. Veterans can concentrate on higher-level tasks, raising productivity across the site.

Cost reduction: The aforementioned labor savings and reduction in rework lead to overall on-site cost reductions. Shorter work times reduce labor costs, and material waste or rework expenses caused by mistakes are avoided. Efficiency gains free up resources for other tasks, raising the overall productivity and cost-effectiveness of projects.

Promotion of site DX: Introducing the AR stake driving guidance app accelerates digital transformation (DX) of surveying and construction. Work that relied on paper drawings and manual records becomes centrally managed as data. Cloud-based information sharing enables real-time reporting and verification between site and office, streamlining workflows. Standardization of stake positioning regardless of the operator—“the same accuracy no matter who does it”—is another major benefit. This aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction (ICT construction) initiative, and the app is expected to spread further as part of site DX.

Utilization of simple surveying with LRTK

The LRTK system is useful not only for stake guidance but also for a wide range of simple surveying tasks on site. Being able to perform various surveying and recording tasks with just a smartphone is a major attraction. Examples of 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 re-measure control points or boundary stakes alone, or easily record key site points as coordinates. If attached to a monopod (pole) and a height offset is set as needed, elevation can be measured with centimeter-level accuracy (half-inch accuracy).

• Photo + location information recording: With the aforementioned positioned photo feature, photos taken with the smartphone automatically include the exact coordinate and camera orientation. This allows clear recording of completed stake locations and tracking of defects found during inspections. Saved photos sync to the cloud immediately and can be shared instantly with remote managers.

• 3D scanning for as-built understanding: It is also possible to record the site as point clouds (3D data) using a smartphone’s LiDAR sensor or camera. Because LRTK’s high-precision position information is added, point cloud data acquired with a smartphone can be treated in true measured scale. Quickly recording foundation shape or ground undulations in 3D aids volume calculations for embankment and excavation—applications that were previously the domain of dedicated laser scanners or drones are now achievable with a palm-sized device. Acquired point cloud data can be shared via the cloud, making it easy for stakeholders to view and use the data on a PC.

Thus, with LRTK you can complete the sequence from stake driving to surveying and record-keeping using just one smartphone. As an innovative system that overturns conventional wisdom, it will strongly promote site digitalization and efficiency. In the near future, this technology may become an indispensable standard tool on surveying and construction sites. Consider adopting this AR stake driving guidance app on your site and experience its benefits firsthand.

FAQ

Q: What do I need to use the AR stake 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 be ready. High-precision positioning requires reception of correction information via the internet (or Michibiki’s augmentation signals), but this is usually handled automatically by the smartphone’s communication. (Currently, Android devices are not supported.)

Q: What level of positioning accuracy can be obtained?

A: Under favorable positioning conditions, you can generally obtain high accuracy of about 2 cm (0.8 in) horizontally and a few centimeters (a few inches) vertically (accuracy may degrade where satellite signals are obstructed). Accuracy varies with GNSS reception conditions, but it is typically sufficient for stake driving and as-built control.

Q: What kinds of sites and applications is it suitable for?

A: It can be used for all kinds of stake driving work, such as placing reference stakes in civil engineering or positioning on building sites. It is powerful even on complex terrain where line-of-sight is hard to maintain, as long as GNSS reception is available. Beyond stake driving, it is useful in various surveying scenarios such as ground surveys, boundary point checks, and recording locations during equipment inspections.

Q: Can people without surveying experience use it?

A: Yes. Thanks to the intuitive on-screen guidance, beginners can handle it easily. You simply follow the arrows and AR markers displayed in the app, so specialized surveying knowledge or complex equipment operation is unnecessary. After basic operational instruction, non-surveying personnel can perform stake setting on site.

Q: How are design data imported and surveying results used?

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 sima format, etc.) to the cloud in advance, you can select that data on site for stake guidance. Conversely, coordinates of points measured on site are saved and shared via the cloud and can be exported to CSV for reflection in CAD drawings. 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 has a splash-resistant design, so it operates normally in light rain. GNSS surveying is generally less affected by weather, so accuracy is largely maintained in rain. AR displays are visible at night if you sufficiently illuminate the ground with a headlamp or work light, so 24-hour operation is possible when needed. However, stop work for safety during heavy rain or thunderstorms with lightning. Positioning may also become unstable in extreme weather conditions such as typhoons.