Solve the Surveyor Shortage with RTK AR! High-Accuracy Surveying Anyone Can Do

The construction and civil engineering industries are currently facing a serious shortage of experienced surveyors. The number of construction workers in Japan has declined by about 30% from its peak, and with the workforce aging, many companies are confronting a situation where "there is work but not enough people" to do it. Surveying is no exception: nearly 40% of technicians are aged 55 or older, while young entrants account for only about 10%. If this continues, there is a growing concern that the transfer of skills will be severed when veterans retire, leading to an overwhelming shortage of personnel capable of performing surveying tasks.

This labor shortage is causing various problems at surveying sites. Surveying that traditionally required a team of two or more to operate heavy equipment such as total stations has increasingly stalled due to a lack of personnel. Work that depends on the experience and intuition of skilled veterans tends to become person-dependent, and if a particular veteran is absent, the entire project can be halted while waiting for surveying. In addition, handwritten field notebooks and manual drafting take time and effort, and there is a risk of rework due to data transcription errors. To eliminate personnel shortages, inefficiencies, and the risk of mistakes, it is essential to transform the surveying process itself.

One promising solution that has attracted attention in recent years is a new surveying method called "RTK AR," which combines high-precision positioning technology RTK with AR (augmented reality). By integrating advanced technology with familiar devices such as smartphones, a solution has emerged that allows anyone to perform highly accurate surveys in a short time even on sites lacking experienced surveyors. In this article, we explain in detail how RTK AR technology can help solve the surveyor shortage and improve field work efficiency and quality control, taking into account trends such as ICT construction, i-Construction, and on-site DX (digital transformation).

GNSS and RTK High-Precision Positioning Technology

First, let’s review the foundational technology that supports RTK AR: RTK positioning. RTK stands for Real Time Kinematic, a method that uses GNSS (global navigation satellite systems such as GPS, GLONASS, and QZSS) signals to measure positions with high accuracy in real time. Standalone positioning can suffer from satellite signal errors that cause deviations of about 5–10 m (16.4–32.8 ft), but RTK positioning uses observations from two receivers—a base station (fixed) and a rover (mobile)—and compares their data to correct errors based on relative differences, achieving horizontal and vertical positioning accuracy of a few centimeters (centimeter-level accuracy, half-inch accuracy).

In civil engineering surveying and construction management, centimeter-level precision is required for accurate layout and as-built verification according to design drawings. Traditionally, accuracy was ensured by total station distance measurement and leveling, but in recent years RTK-GNSS has advanced, and methods for obtaining high-precision coordinates directly from satellites are becoming widespread. The Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative also recommends RTK-GNSS as part of ICT construction, and RTK has become indispensable for digital surveying on site, such as drone photogrammetry and machine guidance. However, conventional RTK equipment often required large fixed units or expensive antennas and specialist knowledge, which posed barriers to widespread adoption.

Use of AR (Augmented Reality) on Construction Sites

Next, let’s look at AR (Augmented Reality), the other pillar of RTK AR. AR overlays digital information onto real-world images, projecting virtual objects or guides onto the scene viewed through a smartphone or tablet camera, or dedicated goggles. On construction sites, there has been a growing trend to use AR to visualize design data from drawings and coordinates obtained by surveying in situ.

For example, stakeout work that used to rely on drawings and tape measures can be done with AR by displaying virtual stakes and markings on a smartphone screen. Operators can be guided to the correct locations by arrows or virtual stakes on the screen without physically marking the ground, allowing even inexperienced workers to intuitively perform accurate layout. AR can also display planned structure models for as-built verification or visualize the locations of buried utilities at the site to avoid excavation, making it useful for construction management and safety checks. By overlaying digital information on real scenes, AR enables on-site understanding of information that is difficult to grasp from drawings or numbers alone.

That said, using AR outdoors for surveying with high accuracy posed challenges. Traditional AR systems that tried to align without markers or GPS but relied solely on a smartphone camera and sensors suffered from drift as users moved, causing the display to gradually shift. Errors on the order of several meters are inadequate for civil engineering uses, so a method to align virtual models precisely with real-world coordinates was required. Combining with the aforementioned RTK high-precision positioning solved this problem: by basing AR overlays on the accurate coordinates provided by RTK, stable spatial visualization with no drift can be achieved even during long work sessions.

RTK AR Enables “High-Accuracy Surveying Anyone Can Do”

Combining RTK positioning with AR display has brought groundbreaking changes in productivity and labor savings. Surveying tasks that once required a skilled surveyor and an assistant working as a two-person team can now be completed by a single person using RTK AR. Pocket-sized RTK-GNSS receivers that attach to smartphones have been developed, enabling centimeter-level positioning without carrying heavy tripods or prisms—just a smartphone is enough. Moving to a survey point and pressing the “measure” button on the screen instantly records high-precision coordinates, eliminating the need for staff signaling or handwritten notes.

Moreover, the AR navigation feature mentioned earlier allows a single person to accurately handle stakeout and installation positioning. The smartphone screen shows the direction and distance to the target point in real time, and as the user approaches, the virtual marker locks into the specified position. By following this guidance and making minor adjustments, even first-time workers can stand on the intended point. Because novices can reliably set out stakes by following the device’s guidance rather than relying on veteran intuition, anyone can perform accurate stakeout work, enabling rapid upskilling of inexperienced staff. In addition, devices such as iPhones with LiDAR sensors can easily scan the surroundings while walking to obtain 3D point cloud data. Point clouds acquired this way are automatically tagged with absolute coordinates from RTK, allowing immediate use without complex post-processing or alignment.

Thus, RTK AR embeds surveying know-how in the system, standardizing and automating work. Dedicated app interfaces are intuitive and easy to use, so even technicians unfamiliar with specialized equipment can become proficient quickly. Positioning data and photos are automatically recorded digitally, eliminating concerns about manual calculations or transcription errors. With advanced technology support, inexperienced field personnel can immediately produce high-accuracy results, yielding significant benefits for training and eliminating person-dependence.

Streamlining Surveying Operations and Contributing to On-Site DX

Introducing RTK AR dramatically improves efficiency and quality across the entire surveying process. Because data are digitized and shared on site in real time, reporting and inspection lead times are shortened, preventing rework and enabling rapid decision-making. This aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s promotion of on-site DX (digital transformation of construction sites) and is a powerful aid when limited personnel must cover multiple sites. The specific benefits are as follows:

• Alleviating labor shortages and reducing costs through labor saving: Survey crews can be reduced from 2–3 people to 1, easing personnel shortages and significantly cutting labor costs. Fewer people can cover more sites efficiently, directly improving productivity.

• Shorter work times: Fast positioning and automated data processing dramatically shorten the time from surveying to drawing preparation, quantity calculation, and reporting. On-site data can be shared to the cloud and checked immediately, enabling as-built verification that used to take days to be completed the same day.

• Improved surveying accuracy and data quality: RTK-GNSS enables measurements with centimeter-level accuracy (half-inch accuracy), producing high-quality deliverables that meet standards. High-density point cloud measurement captures the whole site, allowing comprehensive data collection without omissions or missed measurements. High accuracy reduces re-measurement work and raises the level of quality control.

• Improved safety: Shorter work times reduce the time workers spend on site, lowering risks of heatstroke or accidents during hot weather or night shifts. On busy road construction, shorter surveying times minimize exposure to danger.

• Reduced human error: Measurements and photos are automatically recorded and organized digitally, eliminating errors from handwritten notes or data transcription. Real-time awareness of missing data prevents rework caused by mistakes.

• Easier skill acquisition and elimination of person-dependence: Simple smartphone app-centered operation enables anyone to learn quickly, reducing reliance on veteran surveyors. Stable surveying with less variability between individuals becomes possible, allowing organizational sharing of know-how.

As shown above, RTK AR resolves many issues related to on-site surveying and strongly promotes construction DX.

Using 3D Point Cloud Data for Precise Quality Control

One-person surveying with RTK AR also makes it easy to capture terrain and structures as 3D point cloud data for quality control. Scanning the surroundings with a smartphone’s LiDAR or camera generates high-density point clouds with accurate coordinates assigned from RTK for each measured point. Simply walking a large site to measure allows you to grasp surface as-built conditions, and data capture includes details that partial sample surveys used to miss. The obtained point clouds record ground undulations and structure shapes in three dimensions, enabling quantitative quality assessments such as automatic calculation of fill and excavation volumes and deviation analysis of shapes. For example, acquiring a point cloud of an entire development site allows later comparison with design data to calculate excess or deficiency of earthwork, or to visually verify terrain changes before and after construction.

Furthermore, point clouds and surveying coordinates obtained with RTK are valuable as the basis of a digital twin. By overlaying your measured point clouds on the same coordinate system as public 3D city models such as the Ministry of Land, Infrastructure, Transport and Tourism’s PLATEAU or your BIM/CIM construction models, you can intuitively grasp deviations from design plans. If as-built data collected on site are overlaid on the design 3D model in AR, you can conduct quantity inspections on the spot or use the data for design-change deliberations. Point clouds shared on the cloud can be checked remotely by stakeholders inside and outside the organization and used as materials for as-built reports and maintenance management. Photos taken with an RTK AR app are automatically tagged with capture position and angle, turning simple image records into precise, map-linked records.

By utilizing 3D data obtained with RTK AR, the actual site can be faithfully reproduced digitally and visualized, enabling precise quality control and consensus building that were difficult with traditional methods.

Case Studies: Use at Construction Sites and Municipalities

Actual sites that have introduced RTK AR report corroborating results.

Construction site efficiency case: At one civil engineering site, introducing RTK AR dramatically shortened surveying time. As-built measurements that previously took two people a full day were completed by one person in a few hours, achieving approximately over 70% reduction in work time. Despite this, data density improved markedly, enabling full-site capture and early detection of defects that sampling inspections had previously missed. As a result, rework and additional construction were prevented, yielding significant improvements in both quality assurance and shortened construction schedules.

Municipal use case: Local governments have also begun using RTK AR for on-site surveying DX. For example, Fukui City promptly implemented an RTK AR system in 2023 for damage surveys following disasters. Because staff can start surveying disaster sites immediately with a smartphone, the need to travel back and forth between the field and the office has been greatly reduced, enabling rapid, detailed recording of damage. This shortened lead times from recovery planning to construction start, contributing significantly to early restoration and cost savings. The relatively low introduction cost is attractive to municipalities, and performing surveys in-house rather than outsourcing has led to cost reduction and the internalization of technical skills. Inspired by such successful cases, other municipalities are increasingly considering RTK AR adoption.

Conclusion: Simple Surveying and AR Display with LRTK

RTK AR technology can be a powerful solution to the shortage of surveying technicians. Even without enough skilled personnel, digital technology makes it possible for anyone to perform high-precision surveying and balance efficiency with quality. A representative example is the smartphone-attached RTK system LRTK. By attaching a dedicated device to a smartphone and launching the app, the site itself becomes a high-precision surveying instrument, enabling end-to-end tasks from positioning to stakeout guidance, point cloud scanning, and cloud sharing. Newcomers without specialist knowledge can immediately become effective, and the issue of “waiting for surveying” when veterans are absent can be resolved. In fact, many construction companies and municipalities have begun adopting LRTK for simple surveying and AR display, achieving labor savings and DX simultaneously.

Sites struggling with labor shortages stand to gain the most from introducing this new surveying method based on RTK AR. Consider proactively adopting technologies like LRTK that enable high-accuracy surveying anyone can do, and take a step toward the next generation of smart construction.