AR Inspections Are Changing This Much! The Present and Future of As-Built Inspections

Table of Contents

• What is AR inspection?

• Challenges of traditional as-built control

• Field use of AR technology: immediate checks through visualization

• Benefits of introducing AR inspections

• Points to consider when introducing AR

• Simple surveying realized with LRTK

• FAQ

What is AR inspection?

On construction sites, comparing as-built structures with drawings to confirm “Is this really built according to the design?” is a routine task for engineers involved in construction management. In recent years, however, this familiar scene has been dramatically transformed by AR (Augmented Reality) technology. By simply pointing a smartphone or tablet camera, digital drawings and 3D models can now be overlaid on the real view at full scale. You can intuitively superimpose the actual site and the design data, and immediately confirm on-site whether things are proceeding according to plan. This enables quality checks with unprecedented speed and certainty. The immediacy of on-site inspections has improved dramatically, and AR is attracting attention as a new technology that strongly supports DX (digital transformation) in construction management.

As-built control itself is a quality assurance process in civil engineering and building works that measures and verifies whether completed structures or formed terrain match the shapes and dimensions specified in the design drawings. During and after work, heights, thicknesses, slopes, and other measurements are taken at designated survey points, and deviations from design values are checked to determine pass/fail. Traditionally, staff would painstakingly measure heights and thicknesses using levels or total stations, then take the results back to the office to cross-check measured values against the drawings. Naturally, immediate on-site confirmation was not possible and the work took time and effort. As a next-generation method expected to solve these issues, as-built inspections using AR (as-built AR checks) have emerged. Applying AR technology to as-built control makes it possible to digitally “visualize” construction results on site and check as-built conditions instantly. Driven in part by the Ministry of Land, Infrastructure, Transport and Tourism’s *i-Construction* initiative, this approach has moved rapidly into practical use in recent years. The spread of the latest smartphones with high-performance cameras and LiDAR sensors means everyone can easily use AR in daily work. AR is now becoming active in the field of as-built control.

Challenges of traditional as-built control

As-built inspections (as-built control) are essential for ensuring quality, but traditional methods come with many inefficiencies and problems. Let’s summarize the representative issues.

• Long working hours: Because staff measured each survey point one by one using levels or total stations, vast amounts of time were required when sites were large or many survey points were involved. It was not uncommon for the process of bringing measurement results back and compiling them on drawings to take several days. The long quality-check cycle often caused rework.

• Dependence on manpower and skilled technicians: Accurate measurement and evaluation require experienced personnel such as surveyors, and two-person teams are frequently needed. With chronic labor shortages and an aging technical workforce, ensuring quality with limited personnel has become a major burden. Measurements that rely on the experience and intuition of veterans tend to be person-dependent and difficult to transfer.

• High equipment costs: Millimeter-level high-precision measurements require specialized equipment such as total stations (TS) and RTK-GNSS receivers, and assembling these can require an initial investment on the order of several million yen. Maintenance costs and theft risk also exist, making adoption difficult for small and medium-sized companies.

• Measurement errors and recording mistakes: Manual surveying workflows allow small errors to accumulate each time, and human error can creep in when transferring numbers noted on site to drawings. Discovering recording mistakes later can necessitate remeasurement and rework.

• Burdensome report creation: Preparing as-built drawings and reports based on measurements for submission to clients is a heavy task for field staff. Organizing photos and plotting measurements on drawings takes time, and sometimes the data collected on site cannot be effectively used for quality analysis.

• Delayed discovery of defects: Even if there are construction defects such as insufficient thickness or incorrect slope, these are often not noticed immediately; they are discovered after bringing data back and drawing it up—frequently the next day or later. By the time problems are discovered, concrete may have hardened or heavy equipment may have been removed, causing extra labor and cost for rework.

As described above, traditional as-built control methods suffer from a lack of immediacy and heavy burdens in terms of personnel and cost. There was a clear need for a new inspection method that can grasp as-built conditions accurately and intuitively in real time.

Field use of AR technology: immediate checks through visualization

So how can AR technology be used on actual sites? By overlaying digital information and directly “visualizing” as-built confirmation on site—rather than checking on drawings—you can perform immediate checks on the spot. Examples of use cases include:

• AR overlay of design models: Display 3D design data (BIM/CIM models, etc.) of buildings and civil structures over the site view to intuitively confirm the placement and dimensions on the spot. You can check through the camera whether columns or walls in the middle of construction are offset from the design positions. Differences from the intended finished shape that were hard to grasp from paper drawings or numerical data can be immediately understood as life-size visuals in AR.

• Heatmap display of as-built deviations: It is becoming common to compare 3D as-built data obtained after construction (for example, point cloud scans) with design data and display deviations as a color-coded heatmap for on-site confirmation. If a heatmap automatically generated in the cloud from a comparison of the design model and the as-built point cloud is downloaded to a smartphone and overlaid on the camera view, it becomes instantly obvious which areas are higher or lower than the design. For example, evaluating surface coverage such as embankment or pavement thickness and immediately correcting defective areas supports a faster PDCA cycle.

• AR visualization of buried objects: The positions of structures and pipes buried underground can be displayed in AR for “see-through” confirmation even after backfilling. For instance, in sewer pipe work, if you scan the pipe with a smartphone before burial and store position-tagged point cloud data in the cloud, you can later identify the pipe’s alignment and depth through the smartphone screen even after it is covered. This lets anyone identify buried objects on the spot without marking the surface or carrying drawings, helping prevent construction mistakes and improve safety.

• Other applications: AR can also be used to display construction ranges and height references to guide heavy equipment operators, or to virtually mark concrete pour locations in advance. In training and education, AR environments that replicate sites can be used to practice safety procedures or support skill acquisition for work processes. The range of applications is expanding, but particularly the combination of as-built control × AR is seen as a use case that yields benefits soon after introduction.

By incorporating on-site confirmation via AR display, the workflow of as-built control itself is undergoing major transformation. Because data can be shared and checked on the spot, “immediate inspection and instant feedback” become possible, reducing rework and speeding decision-making. Remote on-site verification (*remote inspection*) and AR-based as-built inspections are still new initiatives, but in the future they are likely to become commonplace, enabling real-time quality control that bridges the site and the office. AR inspections are transforming the present state of as-built inspections and becoming the future standard.

Benefits of introducing AR inspections

How do the problems described earlier get resolved when you introduce AR-based as-built inspections? Here are the main benefits.

• Real-time confirmation and rapid corrections: Because as-built conditions can be checked immediately on site, the time lag from measurement to pass/fail determination disappears. If defects are found, corrective action can be taken on the spot, minimizing rework. There are dramatic time-saving reports—for example, inspections that used to take half a day have been completed in 5 minutes of actual work.

• Improved efficiency and reduced manpower: With just a smartphone and AR, one person can perform surveying and inspection, dramatically improving team productivity. Tasks that relied on the experience or intuition of veterans can be replaced by technology, so anyone can carry out efficient, high-quality construction management. This is a major advantage for ensuring quality with a small workforce amid chronic labor shortages.

• Cost reduction: You don’t need to purchase a full set of expensive surveying equipment; the solution can be introduced with a reasonable initial investment consisting of a smartphone and small devices. Efficiency gains in inspection and surveying, reduced rework, shorter schedules, and lower labor costs can also be expected. Deploying one smartphone per person often fits within budgets, making this a highly cost-effective solution.

• Improved accuracy and reliability: Centimeter-level positioning accuracy (half-inch accuracy) through RTK-GNSS and high-resolution point cloud measurement using smartphone LiDAR dramatically increase the reliability of as-built data. Measurement results are automatically saved to the cloud and can be output and used in formats that comply with the Ministry of Land, Infrastructure, Transport and Tourism’s as-built control guidelines. In recent years, AR use in as-built control has begun to be officially accepted, and data and records obtained via AR are now at a level that can be trusted as inspection documentation.

• Efficient data use and streamlined record tasks: Measurement data and site photos are saved and shared to the cloud on the spot, eliminating the need to transcribe notes into paper logs or replot data on drawings later. Point cloud data and coordinate information can be exported in industry-standard formats such as CSV, SIMA, and LAS, and seamlessly imported into existing CAD or GIS systems. Past measurement data can be easily searched and referenced in the cloud, greatly improving the efficiency and accuracy of record management compared to paper ledgers.

• Improved safety: Because you can measure remotely without entering hazardous areas, AR contributes to site safety. For example, even for steep slope surveys, you can check heights using AR from below to reduce risk. AR visualization of buried objects also reduces the risk of accidentally damaging pipes or cables during excavation. In this way, AR adoption brings great benefits not only in efficiency but also in safety.

As described above, AR-based as-built inspections are a revolutionary solution that increases the immediacy and accuracy of quality control while drastically reducing human and time costs. Many engineers who experience the benefits on site say they “can’t go back to the old way.” As understanding of these benefits spreads, AR inspections are expected to be adopted on more and more sites.

Points to consider when introducing AR

When newly introducing AR-based as-built inspections, keep the following points in mind to maximize the benefits.

• Phased implementation and internal training: Although AR surveying and inspection are intuitive and easy to adopt on site, it is advisable to provide basic operation training and set rules for data handling at the start. Deciding file naming conventions for acquired data and cloud sharing procedures in advance will prevent confusion during operation. Start by piloting on a few projects to verify accuracy and effectiveness, then scale company-wide based on the results. When using for the first time, verify errors against known control points to deepen understanding of devices and data.

• Combining with existing methods and data integration: Initially, use AR alongside conventional surveying equipment and methods—for example, compare measurements obtained with LRTK to total station measurements to understand error tendencies. Also test in advance whether cloud-exported data can be smoothly imported into existing CAD software and photo management systems. LRTK supports industry-standard data formats and is highly compatible with existing operations, but preparing operational workflows beforehand will make on-site use smoother.

• Prepare compatible devices: To run AR apps and point cloud scanning comfortably, provide the highest-performance devices possible. Generally, the latest iPhones and iPads and high-end Android devices are recommended. Older models may not support AR processing or LiDAR scanning or may run slowly. Large-screen tablets are suitable for detailed point cloud review, so consider using them on site according to the application.

Simple surveying realized with LRTK

One solution gaining attention for easily introducing AR-based as-built inspections on site is LRTK. LRTK is an innovative technology that converts a smartphone into a centimeter-class surveying device by attaching a small high-precision RTK-GNSS antenna to the phone. By applying real-time kinematic (RTK) satellite positioning corrections, it reduces GPS positioning errors that are typically several meters (several ft) to several centimeters (several in), allowing high-precision surveying with palm-sized equipment. Combined with LiDAR scanners and high-performance cameras built into the latest smartphones, you can scan the surroundings to obtain dense 3D point cloud data and complete tasks on the spot such as volume calculations, embankment quantity measurements, and checks of buried pipe depths. Acquired point cloud data and photos are automatically shared to the cloud, enabling you to confirm as-built conditions in real time from a remote office. No specialized equipment or complex setup is required—just attach the device to your smartphone, launch the app, and positioning begins immediately.

This kind of LRTK-based simple surveying is spreading rapidly across many sites. Developed with the aim of creating a “one-device-per-person universal surveying tool,” its affordable introduction cost has quietly sparked a trend at many construction sites. If you haven’t yet tried high-precision positioning or AR inspections, consider introducing LRTK. Once you experience the labor- and efficiency-saving benefits, you may find you can’t go back to the old way. With “as-built control DX starting with your smartphone,” site productivity and quality assurance will accelerate even further.

For product details or questions about introduction, please feel free to [contact us](https://www.lrtk.lefixea.com/contactlrtk). Let LRTK’s simple surveying bring your site forward into next-generation construction management.

FAQ

Q: What is AR inspection? A: It is an as-built control method that displays drawings and design data in AR over the actual site to check on the spot whether structures after construction match the plan. Rather than performing as-built inspections with paper drawings and surveying instruments, you visualize them digitally with smartphones to enable real-time, intuitive quality checks.

Q: What equipment and preparations are required to introduce AR inspections? A: Basically, you need a smartphone or tablet that supports AR display and high-precision positioning, a compatible high-precision GNSS receiver (RTK), and an application. For example, attaching an RTK-GNSS device like LRTK to the latest iPhone or Android device lets you combine centimeter-level position information and AR functions to perform as-built checks. In addition, digitalized design data such as prepared drawings or BIM/CIM models are indispensable.

Q: Is measurement accuracy sufficiently ensured? A: Yes. RTK-GNSS provides positioning with errors within a few centimeters, meeting the measurement accuracy required for as-built control. A GNSS receiver attached to the smartphone receives correction information in real time based on control points to accurately align 3D models and point cloud data with site coordinates. Verifications conforming to the Ministry of Land, Infrastructure, Transport and Tourism guidelines have been conducted, and the effectiveness of AR-based as-built inspection methods has been officially confirmed.

Q: How much does it cost to introduce? A: Introduction costs are significantly lower than traditional surveying equipment. By leveraging a commercially available latest smartphone and adding a small GNSS device, initial costs are roughly equivalent to a single high-precision GPS receiver and are very reasonable. Subscription-based plans are also available so you can operate at low cost for only the period required. Specific pricing depends on configuration and contract terms, but even provisioning one device per person typically yields a favorable cost-benefit balance.

Q: Is it compatible with Ministry of Land, Infrastructure, Transport and Tourism standards? A: Yes. Acquired point cloud data and design-comparison results can be output and submitted in formats that comply with the ministry’s as-built control guidelines. The latest guidelines even include wording indicating that “if as-built measurement results projected on site via AR are used for pass/fail determination, submission of traditional as-built control forms is not required,” and AR-based as-built control methods are increasingly being officially accepted. Thus, introducing AR inspections on site can be operated without issues regarding handling inspection documents.