AR markers that bring innovation to the field: a new approach to labor and efficiency savings

Table of contents

• Introduction

• What is an AR marker?

• Use cases of AR markers

• Benefits brought by AR markers

• Challenges and countermeasures when introducing AR markers

• The future of field operations opened by AR markers

• Simple surveying with LRTK

• FAQ

Introduction

In recent years, a new approach called AR markers has attracted attention in fieldwork for civil engineering and construction. This method combines AR (Augmented Reality) technology with positioning technology to display virtual markers (lines, pins, etc.) on the real-world view through a camera, making it appear as if physical markers actually exist on site. For example, simply pointing a smartphone can make boundary lines or pile locations appear on the ground, enabling accurate positioning by merely “looking” at the site. Such AR markers hold the potential to revolutionize traditional surveying and staking work.

Conventionally, field tasks like surveying and pile driving required skilled surveyors operating equipment with multiple people, installing batter boards and staking positions based on drawings. However, amid labor shortages due to a declining birthrate and aging population and the push for workstyle reform, there is a strong demand for methods that allow one person to perform surveying and positioning quickly and accurately. AR technology is expected to meet this need. By using AR markers, field personnel can be guided to target positions with a smartphone in hand or display virtual marks on the spot for confirmation, achieving substantial labor savings and efficiency improvements.

This article focuses on AR markers that bring innovation to the field, explaining in detail how they work, their benefits, concrete use cases, and key points for introduction. At the end, we touch on simple surveying using LRTK, a solution that lets you easily experience these new technologies, and present the forefront of field DX.

What is an AR marker?

In short, an AR marker is a new fieldwork method that combines high-precision GNSS positioning (RTK: Real Time Kinematic) with AR display. A dedicated compact RTK-capable GNSS receiver is attached to a smartphone or tablet, and the device’s current position is calculated in real time with centimeter-level accuracy (half-inch accuracy) using correction information delivered from satellites. At the same time, virtual lines, pins, and other markers are overlaid on the AR app’s camera view to intuitively indicate target points on drawings or positions to be installed.

With conventional smartphone AR, the built-in GPS has errors of several meters, making it difficult to align virtual objects accurately with the real world. The innovation of AR markers lies in solving this problem through the high-precision positioning of RTK, making the virtual and real world nearly coincide. Field personnel can reach drawing-specified points simply by following the AR markers shown on the screen. Upon reaching the target, they point the smartphone and confirm where the virtual marker shown on the screen corresponds on the actual ground, then perform tasks such as driving a stake or marking that position. Conversely, it is also easy to instantly display the coordinates of points measured on site in AR and compare them with design data to check for consistency.

Thus, AR markers can be regarded as a next-generation surveying and construction solution that fuses “centimeter-level positioning” and “visual AR navigation.”

Use cases of AR markers

• AR visualization of land boundaries: AR visualization of boundary lines is powerful in on-site boundary meetings and parcel boundary confirmations. Previously, people had to rely on boundary stakes or temporary marks and say “the boundary is around here,” but displaying a virtual boundary line on a smartphone screen enables all stakeholders to instantly share the boundary location. By viewing the same AR display, parties can intuitively point and say “this is the boundary,” deepening mutual understanding with neighboring landowners and facilitating smoother agreement formation.

• AR guidance for pile driving: Accurate positioning is critical in pile driving for civil engineering. Traditionally, survey personnel measured locations with tape measures and transits based on drawings, chalked the ground, or drove wooden stakes as markers, which required manpower and time. With AR markers, a smartphone can navigate to preconfigured pile positions, and when arriving at the target, a virtual pile (AR marker) is displayed standing on the ground in the real-view screen. Because workers need only install the actual pile at that point, intermediate chalking steps can be omitted. Reports indicate cases where pile positioning with traditional optical surveying took about six times longer than the latest AR guidance, showing that AR guides can drastically shorten work time. Moreover, in steep slopes or waterside areas where installing physical markers is difficult, AR can indicate positions on the screen, making pile-driving guidance feasible in scenes that were previously challenging.

• AR verification of as-built conditions: AR markers are also useful for as-built inspection during and after construction and comparing results with design drawings. For example, overlaying a design model of a completed structure onto the real view in AR allows immediate confirmation of whether the structure’s position and shape match the drawings. It is also easy to display measured on-site point data in AR on the spot and compare it with design values to verify deviations. Measurement results and current-condition photos can be shared to the cloud instantly, enabling real-time as-built confirmation and instruction from remote offices. Compared to traditional checks on drawings, AR-based visual verification is much easier to understand and helps prevent mistakes and rework.

Benefits brought by AR markers

• Work with fewer people and shorter time: Using AR markers can drastically reduce tasks that previously took a surveying team a long time for positioning. With high-precision GNSS performing both position measurement and target guidance simultaneously, one person can complete work in a short time, leading to productivity gains through labor savings.

• Intuitive and simple operation: Since users only follow AR guidance on the smartphone screen, even non-experts can easily find points. The burden of complex coordinate calculations and drawing interpretation is reduced, and the system can be used on-site after a short training period, directly contributing to operational efficiency.

• Instant verification and information sharing: Measured results can be immediately displayed in AR and compared with the design model on site. By taking photos and sharing them with positioning data via the cloud, stakeholders in remote locations can share the situation in real time, enabling rapid deliberation and decision-making.

• Cost reduction: A smartphone plus a compact RTK receiver can sometimes reduce initial investment compared to purchasing expensive specialized surveying instruments or total stations. Compared with conventional methods that require renting multiple devices or paying for manpower, a one-person-one-smartphone survey workflow can be economically advantageous.

• Improved safety: AR guidance allows indicating points from a safe distance or performing non-contact measurements even in hazardous locations, reducing the risk of workers entering dangerous areas. Because surveying can be performed without adopting awkward postures or requiring assistants, even at heights or on unstable ground, accident prevention is improved.

Challenges and countermeasures when introducing AR markers

• Matching required accuracy: Positioning accuracy with AR markers is generally on the order of several centimeters, which is sufficient for boundary display and pile-driving guidance but is not suitable for millimeter-level accuracy management or tiny displacement measurements. For tasks requiring very high precision—such as establishing reference points or deformation measurement—optical surveying instruments or high-performance laser scanners remain necessary. It is important to use different methods according to the application and select the technology that meets the required accuracy.

• Dependence on GNSS environment: In downtown areas with high-rise buildings, forests, or tunnels, satellite signals can be blocked and accuracy may suffer. In such cases, switch to local surveying from known points (offset measurements), or fix RTK at a temporarily open location and continue measurements in relative mode. For critical points, perform accuracy verification in the field environment in advance and, if necessary, combine conventional methods to ensure reliability.

• Handling equipment and power management: Although the smartphone + GNSS receiver combination is convenient, considerations for dust/water resistance and battery management are essential in field use. For long-duration work, supplement power with mobile batteries, and use straps or other fall-prevention measures for equipment. Initial operation may require some acclimation, but UIs are often intuitive, and users can become proficient through short on-site training.

• Consistency with existing data: When integrating surveying results with existing drawings or GIS data, pay careful attention to coordinate system consistency. Confirm in advance whether the system supports the plane rectangular coordinate systems and elevation references (geoid heights) used in Japanese public surveying, and check data compatibility by reconciling output coordinates with existing materials. Be careful to avoid coordinate shifts due to configuration errors.

The future of field operations opened by AR markers

With the advent of AR marker technology, surveying and construction sites are beginning to change dramatically. It truly is a groundbreaking technology that “brings innovation to the field.” An era in which anyone can perform high-precision positioning and surveying with just a smartphone is approaching, and tasks that once relied on skilled workers’ experience and intuition are becoming digitized and automated. This aligns with construction DX initiatives such as i-Construction promoted by the Ministry of Land, Infrastructure, Transport and Tourism, and AR markers have great potential to help solve challenges such as labor shortages, productivity improvement, quality assurance, and safety management.

In Japan in particular, a style in which each field staff carries a pocket-sized surveying device and performs high-precision surveying and as-built management alone is gradually spreading. This innovative workflow, unimaginable in the past, allows engineers to measure immediately, make judgments, and share results with stakeholders, dramatically improving efficiency and quality across the project. Of course, AR markers will not replace every scenario; there will remain situations where total stations and traditional surveying methods are appropriate. However, AR markers will become a commonplace tool for everyday civil surveying and construction management. As 5G networks are deployed and next-generation satellite positioning advances enhance accuracy and reliability further, precise positioning using AR will cease to be a futuristic dream and become an emerging new norm.

Simple surveying with LRTK

Finally, we introduce LRTK as a solution that makes it easy to adopt AR marker technology. LRTK is a high-precision GNSS positioning platform developed by a startup originating from Tokyo Institute of Technology, offering a one-stop set of a dedicated compact receiver, app, and cloud services with the concept of turning a smartphone into a centimeter-level surveying instrument (half-inch accuracy).

For example, a palm-sized RTK receiver called LRTK Phone is attached to a smartphone for use. It weighs on the order of several hundred grams, is very lightweight, dust- and water-resistant, and has a built-in battery. It connects to a smartphone via Bluetooth or Lightning, and supports network-based RTK correction data and Japan’s QZSS Michibiki (CLAS signals), enabling real-time centimeter-level positioning (half-inch accuracy) anywhere in the country.

Using the dedicated LRTK app, in addition to basic functions such as single-point measurement, continuous positioning, and averaging measured points to improve accuracy, you can easily use AR-specific features like visualizing and navigating points in AR and photogrammetry to obtain coordinates of objects via the camera. Measured points are instantly plotted on a map, and photos taken are tagged with high-precision position and orientation information. Cloud integration allows captured survey data and images to be shared with the office on the spot, and later displayed in 3D or downloaded from a browser with a single tap.

By leveraging LRTK, simple surveying with just a smartphone becomes possible even without expensive specialized equipment. LRTK covers everything from positioning to recording and data sharing in an all-in-one manner, offering ease of introduction and cost benefits for small- to medium-scale construction sites and surveying projects. Field reports include comments such as “Thanks to LRTK, one-person-one-smartphone surveying has become a reality,” making it a catalyst for mainstreaming AR marker technology. If interested, please check the LRTK official site for more information.

FAQ

Q: What is required to use AR markers? A: In addition to a smartphone (ideally a device with a high-performance camera or LiDAR), you need an RTK-GNSS receiver capable of centimeter-level positioning (e.g., an LRTK device) and a surveying app that can use that data to display AR. You also need an Internet connection to receive RTK correction data (or an environment that can receive QZSS Michibiki CLAS signals). Additionally, prepare the coordinate data of points and lines you want to display or guide in advance and load them into the app.

Q: How accurate are the displayed positions? Is it comparable to conventional surveying instruments? A: Using RTK-GNSS provides accuracy on the order of several centimeters. This is comparable to conventional total stations or dedicated GNSS instruments. Although some error may occur depending on environment and satellite reception conditions, the accuracy is perfectly adequate for uses such as boundary confirmation or marking pile locations.

Q: What is LRTK? How is it different from RTK? A: RTK is the name of a high-precision positioning technique, while LRTK is a compact device (product name) that enables easy use of RTK positioning with a smartphone. By attaching an LRTK receiver to a smartphone, the phone can perform RTK-based centimeter-level positioning and function as a surveying instrument. In other words, LRTK is a tool that makes RTK technology easy to use on site.

Q: Are operation and configuration difficult? A: No, operation is simple. Attach the LRTK device to your smartphone, launch the app, and follow on-screen instructions to perform measurements and AR displays. Initial setup only requires configuring reception of GNSS augmentation services and connecting to the smartphone—no special procedures are needed beyond that. Someone with basic surveying knowledge should be able to use it intuitively.

Q: Can GNSS positioning be used in any environment? What happens in areas with poor reception? A: GNSS positioning using satellite signals achieves higher accuracy in open-sky locations. In forests with dense trees or urban areas with many high-rise buildings, satellite signals may be blocked or reflected, degrading accuracy. Satellite positioning generally cannot be performed underground or indoors. In such environments, perform calibration (position adjustment) using known on-site points or combine with conventional surveying methods as appropriate. However, the development of Japan’s QZSS has improved positioning stability in urban areas compared to before, and outdoors it now provides practically usable accuracy in many environments.

Q: Will smartphone AR surveying make conventional surveying instruments unnecessary? A: For many purposes such as boundary confirmation and pile driving, smartphone + RTK can increasingly serve as a substitute for traditional surveying. However, conventional instruments will not become entirely unnecessary. For example, tasks that demand millimeter-level precision like setting reference points or indoor measurements may still be better suited to total stations and other optical instruments. Nonetheless, the number of use cases where smartphone AR surveying sufficiently covers tasks such as temporary stake placement and as-built checks will continue to grow. It is realistic to replace parts of the workflow with AR surveying while combining it with traditional instruments as needed.

Q: Are introduction and running costs high? A: A configuration of a smartphone plus a compact RTK receiver and an app often costs less than newly introducing a total station or conventional high-precision GNSS equipment. If you already have tablets or smartphones, you may only need to bear the cost of the receiver and service fees. However, if you use satellite communication or Internet-based services (such as Ntrip) to obtain RTK correction data, usage fees may apply. There are solutions like LRTK that offer low-cost subscription plans or free augmentation signals, so consider options based on your budget and usage frequency.