Can surveying to design verification be completed on a smartphone!? How AR technology is changing exterior construction sites

On exterior construction (landscaping/exterior works) sites, rework and troubles often occur because work cannot be carried out exactly as the design drawings specify. A slight deviation from the site boundary can lead to disputes with neighboring properties, or an error in slope can prevent rainwater from draining properly—small mistakes can cause big problems. Why do these mismatches occur? Behind them lies a gap in how well the design intent is communicated to the field and the difficulty of sharing information on site.

In recent years, AR (Augmented Reality) technology has attracted attention as a trump card for solving these issues. Improvements in the performance of smartphones and tablets have made it possible to utilize AR on site without special equipment. In fact, tools have appeared that allow surveying and drawing verification with a single smartphone, and they are poised to transform exterior construction sites. This article looks back at typical design mistakes in exterior work and their causes, explains in detail how a smartphone-centered workflow using AR technology can solve these problems, and touches on the effects of AR-based visual consensus building, its use for client proposals, and its contribution to work-style reform enabling efficient operation with fewer people. At the end of the article, we introduce the latest tool that supports this realization, LRTK.

Typical design mistakes and construction troubles in exterior work

On exterior sites, small measurement errors or misunderstandings can cause discrepancies between the design and the finished result. Typical failure examples include the following:

• Boundary or positional deviations causing trouble: Misplacing a fence or wall so that it extends into a neighboring property after completion, or having gate positions shift from the drawing and requiring rework.

• Problems due to height or slope errors: Insufficient ground elevation measurement leads to incorrect paving or drainage slopes. After completion, rainwater may pool, or stair step heights may differ from the plan.

• Design collapse due to dimension errors: Misreading the approach width or garden layout dimensions leads to parts that do not fit as shown on the drawings when actually built. As a result, the design balance is disrupted and rework becomes necessary.

Most of these mistakes can be prevented by thoroughly confirming measurements and meetings before construction, but in the field people are often pressed for time or overlook detailed instructions on drawings. When multiple contractors are involved, differing interpretations and lack of coordination can also create mismatches. Because exterior work is performed outdoors, weather and terrain have large effects, and the site often requires on-the-spot judgment. If those judgments deviate from the designer’s intent, the finished result will be affected. In short, it is important to accurately share the design intent with the site and detect deviations at an early stage.

Why the design intent is hard to communicate to the site

So why aren’t design drawings and intent sufficiently communicated to the site? Two underlying factors are the understanding gap of drawing information and the fragmentation of information transmission.

First, there is the difficulty of imagining the finished form from the drawings. With only 2D plans and elevations, it is not easy for everyone on site to accurately envision the actual three-dimensional finished appearance. Designers and construction managers can imagine the 3D form in their heads, but some craftsmen and site staff are not good at reading drawings. As a result, even when construction follows the dimensions on the drawings, the finished image may subtly deviate from what the designer intended when fitted to the site.

Next, there is the problem of information being passed in fragments. Detailed specifications and changes decided at the design stage sometimes do not get fully shared with the site as work progresses. Exterior work often involves multiple fields—landscaping, civil engineering, electrical work—and there may be several drawings and instruction documents. For example, if the plan, section, meeting notes with the client, and email instructions are not centralized on site, workers may end up working with only partial information. Such omissions and confusion of information cause discrepancies with the design intent.

Moreover, insufficient communication between designers and contractors should not be overlooked. Paper drawings and verbal explanations alone may fail to convey subtle nuances or the intention of “how this should appear.” As a result, parts not written on the design drawings are left to on-site judgment, and if that interpretation differs from the designer’s expectation, mistakes and design inconsistencies occur.

Thus, there are limits to understanding and conveying drawing information, and an invisible wall has existed between the office and the site. But using AR technology can remove that wall and make it possible for designers, contractors, and clients to share the same completed-image.

Effects of AR-based visual consensus building

AR technology makes the finished image, which is hard to convey with drawings, visible “on site.” Imagine a completed exterior overlaid as CG on the unfinished site when viewed through a smartphone or tablet camera. Because it can be perceived as if the finished product were right in front of you, all stakeholders can intuitively share the design image.

AR-based visual consensus building has various effects. First, it enables the sharing of design intent without mismatch. Clients can confirm the appearance of a gate post or terrace simply by pointing a smartphone at their yard, without paper perspective drawings or models. Construction staff can also grasp three-dimensionally on site what impression a certain angle will give or how it balances with the building. Because everyone sees the same thing and can discuss it, disagreements like “it looked different from what I expected” can be resolved in advance.

It also leads to faster decision-making. For example, if a client asks during a meeting, “How would it look if we raised the fence height a little?”, the height can be changed on the AR and shown immediately. Without rewriting the drawings, everyone can confirm changes on the spot, accelerating consensus on plan revisions. This improves client satisfaction and reduces the risk of major rework later.

Furthermore, it helps promote understanding among site staff. Less experienced staff can understand at a glance “what and how to build” by viewing the completed image in AR. Instead of lengthy verbal or drawing explanations, sharing AR visuals lets the team intuitively grasp construction points, making it easier to align understanding across the team. In this way, AR visualizes the design and aligns everyone’s vector to create an environment that prevents mistakes and discrepancies.

Workflow for AR display, surveying, point-cloud acquisition, and position confirmation using a smartphone

How does the introduction of AR technology concretely change exterior site workflows? Here we follow a series of steps that can be completed using a smartphone, from surveying to design verification via AR display.

• High-precision site positioning and baseline setting: First, measure reference positions on the site accurately with a smartphone. Tasks that used to require total stations or levels for staking and water-leveling can now be done by obtaining coordinates of the current location to centimeter-level accuracy (half-inch accuracy) through a high-precision GNSS receiver connected to the smartphone or by matching known control points. This links the coordinate system of the design drawings with the real-world space and completes the spatial baseline alignment for AR display in a short time.

• Overlay display of design data using AR: Next, load the exterior design data into an AR app on a smartphone or tablet. Prepared 3D models and plan data are overlaid on the camera image and displayed at full scale. For example, a CG model of a planned wood deck or carport appears in a vacant yard and integrates with the real scene. If high-precision positioning is achieved, the outlines and placements of structures will be projected on site as shown in the drawings—effectively performing a “virtual staking-out.”

• On-site measurement and point-cloud scanning: While checking the AR display, perform additional on-site measurements or scans as needed. Using the smartphone camera or built-in LiDAR, you can obtain 3D point-cloud data of the terrain and structures simply by sweeping the surroundings. For example, scan existing trees and site elevation differences to acquire a digital terrain model and check for interference with the design model. On the AR screen you can also measure “how far is it from the building to the wall” or “whether the CG placement aligns with the actual stake positions.” These data acquisitions traditionally required specialized equipment and complex procedures, but the innovation is that they can be done intuitively with just a smartphone.

• Confirming design positions and marking: Compare the AR-projected design model with the actual site conditions and perform final confirmation of construction positions. For example, check whether temporarily placed blocks or spray markings on the ground coincide with the design lines on AR. If there is any deviation, you can correct and reestablish the position on the spot. If it aligns perfectly, it is evidence that the AR-based positioning is accurate, allowing you to proceed to construction with confidence. Also, by following guides displayed on the AR screen for staking or marking, even inexperienced workers can place structures at the design locations. In short, the smartphone screen itself serves as the surveying instrument and staking drawing.

• Data saving and sharing: After completing the series of positioning and AR checks, save and share measurement data and site photos via the cloud from the smartphone. If acquired coordinate values, point clouds, and images showing the AR verification status are automatically uploaded to the cloud on site, it reduces the effort of returning to the office to match drawings or compile reports. Real-time sharing between site, office, and client enables faster decision-making and approval processes.

With the flow described above, surveying, design verification, and record-keeping can all be completed with a single smartphone on modern AR-enabled sites. The key point is that the traditionally separate tasks of “surveying” and “drawing verification” can be performed concurrently. You can measure while confirming the design on site and immediately record the data, eliminating the time previously spent “taking data back to the office and poring over drawings to find mistakes.”

Preventing construction errors by comparing design with as-built on site

The AR-based methods described above also have a tremendous effect on quality control during and after construction. In particular, the ability to immediately verify the design against the as-built on site leads to early detection and correction of construction errors.

Traditionally, it was common to discover problems only after completion, when measurements with a total station or tape measure were taken and then compared to drawings back at the office. If concrete had already hardened or heavy equipment had been removed in the meantime, correcting a discovered error could entail significant cost and effort. Using AR, you can intuitively check on the spot whether construction is proceeding according to the design, preventing mistakes before they become serious.

For example, consider verifying formwork positions with AR before concrete placement. Display the designed shape of the foundation concrete on the smartphone AR screen and overlay it on the on-site formwork. If the formwork position or dimensions deviate from the design model, the discrepancy will be clearly visible on the screen. Immediate corrective instructions can fix the issue before pouring concrete, preventing fatal rework. Similarly, when checking the height and straightness after placing block walls, if you display the design reference lines and height standards on AR, you can detect deviations on the spot. Small tilts or sags of a few centimeters, which might be missed when relying on craftsmen’s intuition, are amplified through the camera and made visible.

As a more advanced use, comparing point-cloud data with design data to visualize errors is now being realized on site. Scan the finished structures with the smartphone LiDAR, compute the differences between that point cloud and the design 3D model in the cloud, and generate a color-coded heatmap image of discrepancies. Import that into the smartphone and display it in AR; you can then intuitively grasp “which parts are higher or lower than the design” when overlaid on the actual structure. For example, highlight in red a part of the slab that is 5 cm (2.0 in) higher than the design. The heatmap AR that makes errors obvious at a glance helps identify areas needing immediate repair and dramatically improves the PDCA cycle of quality inspection.

If on-site design verification via AR becomes routine, variability in construction quality will be greatly reduced and a system that snuffs out potential mistakes on the spot will be established. Construction managers will be freed from the anxiety of “I’ll have to check whether this matches the drawings later…” and can proceed confidently while ensuring quality at each step.

Application to client proposals and progress explanations

AR technology is not only powerful for management and verification by contractors but also as a tool for proposals and explanations to clients. In exterior work, sharing the completed-image with the client at the proposal stage is key to securing contracts and improving satisfaction, and AR makes this communication dramatically smoother.

In proposal-stage use, bring a smartphone or tablet to the client’s home before construction and display the planned exterior design in AR around the garden and entrance. Since you can place CG models of carports, wood decks, plantings, and lighting in the real space, the client can realistically experience how these elements will look on their own house. This not only removes anxiety about “what if it looks different after completion,” but also elicits concrete requests or feedback on the spot, such as “this tree looks taller than I expected, so I’d like a shorter shrub instead.” Because clients can sense texture and depth that catalogs and drawings cannot convey, aligning understanding with the client becomes much easier.

AR is also effective for explaining construction progress. When reporting to clients at a partially completed site, you can create the effect that the completed exterior is visible through the smartphone screen even when only the framework is in place. Statements like “a fence will be installed here later” or “this space will be sodded” are conveyed at a glance when the completed image is overlaid in AR. Clients can imagine the final outcome while waiting for completion and gain reassurance about progress; sudden on-site changes are more easily understood when explained visually with AR.

Moreover, you can respond immediately to client requests for image changes. If, during construction, a client says “I want to expand this flower bed after all,” redesigning typically takes time. But if you adjust size and placement in the AR system, you can show the new plan on the spot. If the client likes it, consensus is reached immediately and rework is minimized. In this way, AR-based proposals and explanations also contribute to building trust with clients. If clients feel “this contractor explained everything thoroughly until the end,” it will lead to higher satisfaction after handover and positive word-of-mouth.

Contribution to work-style reform and small-team operation for exterior contractors

AR technology and smartphone use not only transform on-site work but also contribute to exterior contractors’ work-style reform. They become key to achieving high-quality construction efficiently with limited personnel amid labor shortages and an aging workforce.

First, they help prevent knowledge concentration. Surveying and staking tasks that historically relied on veterans’ intuition and experience can be performed accurately by younger staff with AR and smartphones. Visual guides reduce the “skills only veterans know,” enabling anyone on the team to achieve consistent accuracy. This prevents work from concentrating on specific skilled individuals and promotes sharing of knowledge and know-how. In handovers and new employee training, learning via AR-based hands-on experience rather than oral tradition speeds up skill acquisition.

Next, they enable labor-saving and efficiency. When single-person surveying with a smartphone becomes possible, tasks that used to require two people for total-station surveys can be done by one. A single staff member can walk the site with an LRTK-equipped smartphone, measure required points, and record them one after another, allowing other staff to work on different tasks in the meantime. For small exterior contractors, adopting the latest technology could make it feasible to handle multiple sites in parallel with a small team. If the time from surveying to drawing verification and record-keeping is greatly shortened, the amount of work handled in a day increases, contributing to reduced overtime and securing weekends off.

There are also benefits in responsiveness and information sharing. In the past, when an unexpected issue occurred on site, it was common to return to the office for redesign or reconsideration. But with cloud-connected AR systems, the site situation can be shared immediately and the office can send advice or revised designs. Remote supervisors or designers can discuss while viewing on-site AR footage and survey data in real time, minimizing downtime waiting for decisions. This is a great help for sites operating with few people.

Finally, leveraging AR and smartphones can also make the work itself more attractive, helping recruitment. Sites that master cutting-edge technology appeal more to younger people, aiding talent acquisition. If physical labor burden decreases and productivity rises, employee satisfaction improves. Adopting digital technology can help dispel the industry’s image of being “hard, dangerous, and leaving late.”

Convenience of simple surveying and AR display functions with LRTK

As seen so far, the combination of smartphones and AR brings various benefits to exterior sites. One solution supporting this realization is our company’s “LRTK.” LRTK is a groundbreaking system that converts a smartphone into a surveying instrument with centimeter-level accuracy (half-inch accuracy) by attaching a palm-sized high-precision GNSS receiver to the smartphone and using real-time satellite positioning corrections (RTK method). This allows smartphone GPS, which previously had errors of several meters (several ft), to determine current position with an accuracy of several centimeters (several in). No special configuration is required: simply attach the LRTK device to the smartphone and launch the dedicated app so anyone can immediately use high-precision positioning and AR display.

With LRTK, you can perform the entire workflow on a smartphone—from surveying to point-cloud measurement, position-guidance, and AR projection of design data. For example, attach the LRTK receiver to an iPhone or Android device and walk the site to complete coordinate acquisition of necessary points and 3D terrain scans. Acquired data are saved to the cloud in real time, allowing immediate information sharing with staff in the office. Of course, if you load design drawings or 3D models into the app, you can accurately overlay and display them on site in AR mode. LRTK’s centimeter-class positioning (half-inch-class) enables non-shifting AR projection, making construction management possible without having to imagine things in your head.

Despite these advanced functions, LRTK balances ease of use and low cost from the site perspective. The device itself is compact and lightweight with a built-in battery so it is not burdensome to carry like a handheld GPS or mount on a helmet. Compared to conventional surveying equipment, the initial cost is significantly lower, making it accessible for small and medium exterior contractors. The smartphone app features an intuitive UI, and even site staff without specialized knowledge can master it with short training. It is truly a tool that enables “anyone to perform high-precision surveying easily,” and can be described as the next-generation construction support system compatible with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative.

AR technology and smartphone surveying are accelerating toward becoming the standard in exterior construction as well. By using LRTK, even small teams can efficiently handle surveying to as-built management and achieve both quality and productivity. If you are considering changing your site with smartphones and AR, please consider introducing LRTK. Equip yourself with cutting-edge digital technology and upgrade your exterior construction sites to the next stage.