AR markers that change layout marking work: anyone can easily align positions with high accuracy

Table of contents

• What is an AR marker?

• Traditional layout marking work and its challenges

• How layout marking changes with AR markers

• Benefits of introducing AR markers

• AR technology in construction and the future of surveying

• Recommended simple surveying with LRTK

• FAQ

What is an AR marker?

An AR marker is an image or shape that serves as a "landmark" to display digital information in the real world when read by a camera. When you point a smartphone or tablet camera at a specific marker (image), digital content such as 3D models or lines is overlaid at that location. In other words, an AR marker is a trigger to launch and place AR (augmented reality) content. Examples of AR markers include QR codes, custom geometric patterns, photos, and illustrations.

In the past, artificial graphic markers resembling two-dimensional black-and-white codes surrounded by black frames were mainstream. However, recent advances in image recognition technology have made it possible to use freely designed images such as logos and photos as markers. This enables using parts of construction drawings or on-site signs as AR markers, allowing more flexible use of AR.

Traditional layout marking work and its challenges

"Layout marking work" refers to the task on construction sites of marking reference lines and positions on actual surfaces according to drawings. It includes marking the locations of building columns and walls, the paths of service piping, and drilling points on floors and walls using ink or chalk. While indispensable for accurate construction, traditional layout marking has several issues.

• Labor-intensive and time-consuming: Layout marking is usually done by two or more people. One person measures according to the drawings while another makes the markings. For example, when measuring a set distance from a reference line, workers use a tape measure or laser distance meter to determine the position and mark it with chalk. Repeating this process for many points can take the entire day on large sites.

• Complex procedures and advanced skills required: Accurate alignment requires surveying knowledge and experience. Even when using dedicated instruments like total stations mounted on tripods, skilled operation is necessary. Because the process involves setting reference points, calculating angles and distances from them, and marking the points—a complex process—teams often must rely on veteran surveyors or skilled technicians.

• Risk of human error: Manual layout marking is prone to human mistakes such as measurement errors or misreading. Even one misplaced mark can cause components to not fit later, leading to rework. Noise and pressure on site can make small lapses in attention lead to errors. When only younger or less experienced workers perform the task, uncertainty often remains and veteran confirmation is still required.

• Time and cost burdens: If layout marking takes a long time, subsequent work is delayed and the overall schedule is affected. The cost of keeping skilled personnel for extended periods is significant. Cheap, simple surveying devices often lack the necessary accuracy, forcing teams to use expensive equipment or outsource to surveying specialists. These time and cost burdens impede productivity improvements on site.

How layout marking changes with AR markers

A new method that can solve these problems is layout marking using AR markers. Combining AR markers with a smartphone makes it possible for anyone to intuitively and accurately determine positions. Let’s look at how the work changes in practice.

First, as preparation, load drawing data or 3D models into an AR-capable app and place a reference AR marker on site. For example, attach a marker to a point on the floor and set that position as the reference point (origin). By aligning the drawing’s reference point with the physical marker position in the app, the digital design is ready to be overlaid on the real environment.

Next, when you view the site through a smartphone or tablet camera, virtual lines and marks are displayed on the floor or walls. For instance, lines indicating column centerlines, piping routes, or marks showing drilling points appear perfectly aligned with the actual floor or wall. Workers can simply trace the virtual line with a chalk box or place marks at the indicated positions on the screen.

The biggest difference is the dramatic reduction in alignment effort. Traditionally, workers repeatedly checked tape-measure measurements to ensure each position was correct, but with AR the overall positioning is pre-aligned by the marker, eliminating the need to remeasure each individual point. In extreme terms, layout marking can be completed by "just marking where the screen shows." Because the work is intuitive, highly accurate positioning is possible without advanced surveying skills, allowing younger staff to efficiently carry out layout marking without a veteran accompaniment.

Also, the AR marker method makes it easier for one person to work. With a smartphone in one hand and a marking tool in the other, single-person operation can be possible with some adjustments (while taking safety into account). What used to require pairs of workers can now be completed with minimal personnel as long as the device and marker are available. This labor-saving benefit is especially valuable on sites facing serious workforce shortages.

Benefits of introducing AR markers

Here are the concrete benefits of using AR markers for layout marking.

• Improved accuracy and fewer mistakes: AR-based alignment is based on digital drawing data, greatly reducing human reading errors. Because guides are always displayed at the design-specified positions, you can mark with high accuracy from a few millimeters to about 1 centimeter (0.4 in). As a result, rework and construction errors decrease, improving quality.

• Reduced work time: Measurement and marking can proceed in parallel, dramatically improving efficiency. Complex measurement calculations and redrawing of layout lines become unnecessary, and in some cases tasks can be completed in less than half the time compared to traditional methods. The freed-up time can be allocated to other tasks, contributing to overall on-site productivity improvements.

• Easy for anyone to use: Even without specialized surveying knowledge, workers can follow the on-screen instructions. The intuitive nature of the system makes it easy to train newcomers and non-specialist staff, relieving the burden on veterans and enabling the whole team to work more efficiently.

• Improved communication: Virtual models and lines shown in AR can be shared among multiple people on site. For example, supervisors and craftsmen can look at the screen together and attain a shared understanding like "this wall goes here," preventing miscommunication and simplifying explanations to clients. Sharing the completed-image on site makes client meetings smoother.

• Digital transformation (DX) for recording and collaboration: Systems using AR markers often record positional and work data digitally. You can digitize layout points and share them in the cloud or save photos of marked locations with position information, making information management that is difficult with analog work much easier. This advances the DX (digital transformation) of surveying and layout marking, streamlining coordination with subsequent processes and the creation of reports.

AR technology in construction and the future of surveying

While layout marking using AR markers is revolutionary, AR applications in construction are not limited to this. Markerless AR that aligns positions without markers, and AR combined with GNSS (satellite positioning), are among the next-stage developments.

"Markerless AR" recognizes floors and walls directly with the camera to detect planes and place models. It enables AR display without dedicated markers, making it convenient, but slight errors can occur when placing models with high accuracy in large spaces. For quick visual checks this is sufficient, but for precise layout marking there can still be concerns.

On the other hand, for wide-area outdoor surveying and positioning, integration with high-precision GNSS (such as RTK positioning) is attracting attention. If an RTK GNSS receiver can determine the smartphone or tablet’s position to centimeter-level accuracy, absolute-coordinate-based AR display becomes possible without physical markers. Linking design coordinate data to the current position enables real-time guidance like "move 5 cm east to the specified point" and accurately overlays marks for stake positions on the camera view. The combination of high-precision GNSS and AR is revolutionizing sites by enabling tasks such as staking and infrastructure inspection across large development sites to be performed efficiently by a single person.

Going forward, surveying and layout marking will evolve from using AR markers as an entry point to more advanced AR-plus-positioning technologies. As site DX accelerates, high-precision positioning—once the exclusive domain of specialists—is becoming accessible to anyone. Although adoption is still limited to some advanced sites, it is highly likely that these technologies will become commonplace within a few years.

Recommended simple surveying with LRTK

As a notable solution that leverages AR markers and high-precision GNSS, we introduce a simple surveying system called LRTK. LRTK combines a smartphone with a compact high-precision GNSS receiver and enables positioning and surveying using a dedicated app’s AR features.

In the LRTK system, a palm-sized GNSS device (weighing about 165g) is attached to the back of a smartphone. This device achieves centimeter-level positioning using the RTK method, providing horizontal accuracy of about ±1–2 cm (±0.4–0.8 in) and vertical accuracy of about ±3 cm (±1.2 in). Achieving accuracy comparable to conventional optical surveying instruments or large GNSS equipment with minimal hardware is a major advantage. It also supports network-based correction information and Japan’s Quasi-Zenith Satellite System "Michibiki" CLAS signals, enabling real-time high-precision positioning even in sites with poor communications.

Using LRTK technology makes AR-guided layout marking even more accessible. For example, if stake positions or reference points in construction drawings are loaded into the app as coordinate data, the smartphone screen can display guidance like "X cm remaining to the target point," and you simply walk according to the instructions to reach the correct position. As you approach, virtual stakes or marks appear in the camera view, clearly indicating the installation point. What used to require several people for stake positioning can be completed quickly by one person using LRTK.

LRTK-based simple surveying is being adopted by local governments and construction companies. Its ease of use—just a smartphone and a compact device—has made it a focus as the "first step of on-site DX." Leave behind paper drawings and manual surveying and step into data-driven smart construction. With LRTK-enabled centimeter-level simple surveying, anyone can experience high-precision positioning starting tomorrow.

FAQ

Q: Can layout marking with AR markers really achieve good accuracy? A: Yes. If an AR marker is used for accurate alignment, you can mark positions according to design drawings. Accuracy depends on camera resolution and marker size, but under appropriate conditions AR can indicate positions close to millimeter-level precision. However, absolute accuracy depends on where the marker is placed, so it is important to position the reference marker carefully. For wide-area surveying, combining with high-precision GNSS can keep errors within a few centimeters.

Q: What preparation and equipment are needed to use AR markers? A: No special expensive equipment is required; basically you can start with a smartphone/tablet and printed markers. First load your layout drawings into a compatible app, then attach printed AR markers (or QR codes) at designated on-site positions. By having the camera recognize the marker, you align the drawing coordinates with the actual space. Then follow the on-screen guides to make your marks. Accurate calibration of the drawing and marker positions in advance is the key to success.

Q: Are AR markers effective outdoors under strong sunlight or on large sites? A: AR markers can be used outdoors, but environmental conditions require attention. Under strong direct sunlight the camera may have difficulty detecting markers. Using larger markers, creating shade, or fitting a hood to the tablet can improve detection. One marker has a limited coverage area on large sites, but you can place multiple markers for each area or combine them with high-precision GNSS positioning to handle wide areas.

Q: Are there methods to align positions without AR markers? A: Yes. There are markerless AR and GPS-based AR methods. Markerless AR recognizes surrounding floors and walls directly and is used for small indoor tasks. GPS or GNSS methods can align digital coordinates with real space without physical markers. However, ordinary GPS accuracy is on the order of meters, so RTK-level centimeter accuracy is required for layout marking. Currently, AR marker methods are mainstream because they are easy and accurate, but GNSS-hybrid approaches are expected to increase in the future.

Q: Can people with no surveying or layout marking experience use AR markers effectively? A: Yes. Once you learn the basic operations, beginners can use them. The advantage of AR marker systems is that you get results by following the on-screen instructions. The app is intuitive, and you will grasp the workflow after a few uses. Tips for more accurate use include firmly fixing the marker, keeping the camera steady, and periodically checking for position drift. It’s recommended to try it in a simple location first and then introduce it in actual work sites once you are comfortable.

Q: What is simple surveying with LRTK? A: LRTK combines a compact RTK GNSS receiver and a smartphone app to enable anyone to perform centimeter-level surveying and positioning. Without large surveying instruments or specialized knowledge, an LRTK device attached to a smartphone measures the current position with high precision and guides you to points using AR navigation. It is designed so even newcomers can accurately perform staking and as-built measurements, and its adoption is growing as a "simple surveying solution you can do with just a smartphone." With LRTK, an era has arrived in which everyone can work with surveyor-level accuracy based on clear coordinate data.