Conventional Surveying Methods and Their Challenges

Surveying is an indispensable task in civil-engineering projects, yet traditional methods come with several drawbacks.

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• Accuracy issues in conventional surveying:While total stations and optical levels can deliver high precision, even minor setup errors or human mistakes can introduce significant deviations. For example, failing to verify instrument levelling has led to height discrepancies of several centimetres—forcing a structure to be rebuilt. Such work demands experience and meticulous attention; consequently, accuracy often varies between seasoned surveyors and novices.

• Manual, time-consuming workflows:Traditional surveying and layout operations are largely analogue. Crews bring paper drawings to the site, install batter boards and wooden stakes, then check line and grade—an end-to-end process that absorbs significant manpower and time. Work frequently stalls while waiting for survey crews or due to bad weather. Post-processing is just as burdensome: translating field data into drawings and reports adds another layer of effort to already busy job sites.

• Design–field disconnect:Contractors must visualize the finished structure from 2-D drawings alone, creating ample room for misinterpretation. For complex geometries or challenging terrain, paper plans make it difficult to grasp the final form, and design intent can be lost. Even when briefing owners or other stakeholders on site, relying solely on drawings often lengthens the time needed for clear understanding.

As a result, traditional methods are riddled with inefficiencies—surveying errors translate directly into construction errors, and communication gaps trigger costly rework. A promising remedy is a new surveying approach that blends AR technology with high-precision RTK positioning. The next section explains how this “AR surveying” solution resolves the challenges outlined above.
 

The Impact of Combining AR with RTK Surveying

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The combination of AR and Real-Time Kinematic Positioning (RTK-GNSS) is transforming civil surveying and construction management. By overlaying 3D design models onto the real-world site based on high-precision location data, the following benefits emerge:

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Reducing Construction Errors: Detecting Design Deviations in Real Time

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With AR, design models can be projected directly onto the site, enabling real-time detection and correction of discrepancies between the plan and the actual site. For example, by visualizing the position of rebar and formwork using AR during construction, deviations that would normally be noticed later can be identified on the spot. Constantly verifying position and dimensions according to the design using AR significantly reduces human errors, rework, and dimensional mistakes. In fact, feedback has shown that the use of AR has been effective in "preventing construction errors", and it is expected to be a key tool for ensuring quality.

Shortening Work Time: Reducing Rework and Enabling Quick Verification
 

Surveying with AR + RTK replaces many manual processes with digital methods, leading to a significant reduction in work time. Just reducing the rework involved in adjusting stakes or re-surveying after checking drawings saves a lot of time, but that's not all. For example, on one site, the team used AR to overlay the CIM model on-site and immediately reused the screen captures as meeting materials, achieving significant labor savings.

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What previously took additional surveying and drawing creation can now be done by simply displaying the model in AR and taking photos. By instantly visualizing and sharing necessary information, AR simplifies the workflow and accelerates construction management, contributing to faster project completion and easing the strain of labor shortages.

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Ease of Remote Verification: Information Sharing and Remote Collaboration

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3D design data and surveying information handled by AR can be managed as digital data on the cloud, making it easy for stakeholders to share and verify the same information remotely. Even when not on-site, office staff or clients can understand the current situation through AR screen visuals or models hosted on the cloud. This reduces the need for travel for design meetings or site inspections, leading to savings in travel time and increased productivity.

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In fact, on one project, an attempt was made to explain construction steps during a web conference while live-streaming AR visuals from the site, successfully facilitating smooth communication with remote stakeholders.

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This kind of remote collaboration is particularly important in the context of recent health and work-style reforms, and AR is gaining attention as a tool that accelerates on-site "visualization".

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Specific Use Cases

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Let’s explore how AR + RTK surveying can be applied on actual civil engineering sites through specific scenarios.

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Applications in Surveying

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By integrating AR into surveying tasks, on-site positioning and verification work are dramatically streamlined. For example, previously, positioning was done with surveying equipment based on drawing coordinates, and stakes and markers were placed manually. With AR, the target positions can be displayed on the device screen, guiding the user to the correct locations. As you approach the point, the model appears, making it easy to confirm "this is the design position." In fact, there have been reports of AR being used to accurately display signpost locations even in areas obscured by vegetation.

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Even without physical markers, AR, backed by high-precision RTK, can accurately indicate the target position. Additionally, by simply walking around with a smartphone or tablet, multiple point verifications can be performed, reducing the need for a full surveying team. Since surveying data is stored digitally, it can be easily shared via the cloud and passed on to the next phase of the project. This shift from "measuring and writing" to "seeing and understanding" improves efficiency, reducing the burden on surveyors and accelerating work speed.

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Applications in Construction Management

AR also becomes a powerful tool for construction management tasks. For example, in AR construction management, design models can be overlaid onto the construction site, allowing for on-the-spot verification of whether the work aligns with the design. This includes verifying the position and slope of steel beams and pipes or simulating the work range of heavy machinery and incorporating it into temporary plans. In one case, during the construction of an elevated bridge foundation, a heavy machinery interference issue arose, but after overlaying the heavy machinery model and site conditions in AR and creating image documentation, the situation was understood instantly, leading to rapid resolution.

Spatial issues that are difficult to convey through floor plans or cross-sections can be intuitively shared using AR, bridging the gap in understanding between stakeholders. Additionally, visualizing construction steps in AR makes it easier to share the on-site vision, even with less experienced staff, which helps junior engineers support construction management. Furthermore, by saving AR display photos or videos as construction records, they can serve as convincing documentation for future verification and reporting. For site managers, AR is a next-generation tool that supports quality, schedule, and safety management.
 

Benefits in Infrastructure Inspection

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The usefulness of AR is also increasing in the field of infrastructure maintenance and inspection. When identifying repair areas on aging bridges or tunnels, overlaying pre-made 3D models or drawing information with AR allows workers to quickly determine which components need to be repaired and to what extent. Visualizing underground utilities, in particular, offers a significant advantage.

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AR Visualization of Underground Utilities (Pipes):
With high-precision AR, the location of underground pipelines can be accurately overlaid onto the actual road surface. By understanding the location and type of buried pipes in advance, the risk of accidentally digging into another pipe can be prevented, leading to improved safety.

Workers can check the position of underground pipes, cables, structural specifications, and maintenance history in real time through smart glasses or tablets on-site, allowing them to perform inspections and repairs efficiently and accurately. Additionally, with both hands free to work, flexibility increases, and using AR to guide complex procedures helps reduce the potential for human error.

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In large-scale infrastructure management, such as railways and highways, integrating inspection data into the cloud and displaying it on-site with AR can significantly accelerate decision-making and improve situational awareness.
 

Introducing LRTK: A High-Precision AR Surveying Tool for Everyone

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Finally, we introduce LRTK, a groundbreaking tool that makes AR utilization on-site more accessible. LRTK is a solution developed by our company, consisting of a compact RTK-GNSS receiver that attaches to an iPhone or iPad, along with a dedicated cloud service. With this tool, your smartphone transforms into a versatile surveying device with centimeter-level accuracy, and you can also use its AR functionality to display 3D models directly on-site.

The key feature of LRTK is that no on-site coordinate calibration is required. Traditional AR systems required initial alignment of the model to the real-world site, and as the user moved, the model would gradually drift. However, LRTK uses precise position data from RTK-GNSS to ensure that the relationship between the model and reality remains consistent, even as the user moves around. This makes LRTK the only tool that allows anyone to easily use high-precision AR.

In fact, reports show that even those with limited surveying expertise can accurately display models at the correct positions using LRTK, and its ease of use has gained high praise among site professionals.

By uploading measurement data and design 3D models to the LRTK Cloud, multiple people can share and view the same model remotely, and point-cloud data can be automatically overlaid with design data.

LRTK is truly a next-generation tool that can be used consistently from surveying to construction management and maintenance.