Visualizing Surveying with AR×GPS! New Technology to Boost On-site Work Efficiency

In recent years, the construction and surveying sectors have increasingly adopted digital technologies such as drone surveying and 3D scanners, accelerating on-site innovation known as "construction DX." Against this backdrop, a new technology that combines AR (augmented reality) and GPS to intuitively "visualize" surveying work on-site and dramatically improve on-site work efficiency is attracting attention. By attaching a small high-precision GPS receiver to a smartphone and using AR to overlay surveying data and design drawings onto the real scene, anyone can perform accurate positioning and intuitively verify information without specialized instruments.

This article first summarizes the basics of GPS surveying and its conventional challenges, and then explains new solutions arising from the fusion with AR technology. It also presents concrete examples of efficiency gains on-site and the advantages across phases such as surveying (measurement), construction, inspection, and maintenance. Finally, we touch on ease of adoption, compatibility with existing digitalization efforts, and future development potential, exploring key points of on-site DX enabled by the latest technologies.

Basics and Challenges of GPS Surveying

Surveying using GPS (Global Positioning System) is a method of determining positions on the Earth using signals from satellites. If a receiver has a clear view of the sky, it can measure its position anywhere on the ground, and because it does not require line-of-sight alignment with a target like an optical distance meter (total station), it can perform positioning even when obstructed. Also, as long as reference points exist, coordinates in a global geodetic system can be obtained directly, making post-survey coordinate transformations and plotting on topographic maps smooth. Thus, GPS surveying offers the advantage of efficiently covering wide areas even by a single person, but there have been several challenges when using it for high-precision surveying.

• Ensuring positioning accuracy and technical hurdles: Standalone GPS positioning typically has errors on the order of several meters, which does not meet the accuracy required in construction and civil engineering surveying (several centimeters). Correction techniques such as RTK (real-time kinematic) can reduce errors to a few centimeters, but these require known base stations and dedicated high-performance GNSS receivers, making equipment cost and operational expertise barriers. In addition, conventional optical surveying can suffer from human errors such as improper instrument setup or reading mistakes, so ensuring accuracy often relied heavily on experienced personnel.

• Labor and inefficiency: Traditional surveying work has been manual and labor-intensive. For example, surveying with a total station requires two people—the measurer and the prism holder—and layout tasks such as stake-driving and string-line setup repeatedly occur. Work can be interrupted by bad weather, and project schedules are often delayed while waiting for surveying. Furthermore, post-processing such as converting field-collected survey data into drawings or compiling reports is cumbersome and a significant burden for on-site personnel.

• Information sharing and perception gaps: On-site, contractors often have to imagine the finished form only from paper plans and numerical instructions, leading to understanding gaps between veterans and newer staff. Especially in complex terrain or structures, grasping the completed image from 2D drawings is not easy, and insufficient conveyance of design intent can cause construction errors and rework. During site explanations to clients and stakeholders, plans and materials alone may not effectively convey the image, causing communication loss.

In this way, conventional surveying methods and GPS surveying had scattered issues including the difficulty of ensuring accuracy, low work efficiency, and challenges in information sharing.

New Solutions from Fusion with AR Technology

A trump card for solving these issues is the fusion of GPS positioning and AR (augmented reality) technology. AR overlays CG and data onto the real-world view seen through a camera, allowing virtual information to be drawn in physical space via smartphones or tablets. Applying AR to surveying realizes "visualization of surveying."

Specifically, using one’s position obtained by high-precision GPS as a reference, digital data such as points and lines from design drawings or previously measured coordinates are overlaid onto the real-world scene in real time. For example, if the position and height of a structure from the drawing are visualized on the ground with AR, you can confirm "this will be here" on-site without comparing to paper plans. Conversely, points measured on-site can be shown as virtual markers and shared with the team. This enables layout and verification work that used to be completed in the office after surveying to be finished immediately on-site, allowing confirmation and instructions to be made from the moment measurements are taken.

Combining centimeter-level positioning via RTK with AR displays turns a smartphone into a "high-precision GPS surveying device + see-through overlay." Without expensive equipment or complicated operations, site workers can perform surveying and drawing verification simultaneously with a smartphone in hand, sharply improving productivity and accuracy. Following AR-displayed guides, even non-experts can intuitively set correct positions and heights, reducing human errors and promoting skill transfer. Also, because data is tied to the actual scene, explanations to clients and heavy equipment operators become easier, helping to eliminate communication losses.

Thus, the new method combining GPS surveying and AR is expected as a revolutionary approach that can resolve conventional challenges all at once.

Examples and Expected Scenarios of Improved Work Efficiency

How exactly does AR×GPS improve work efficiency on-site? Below are several case examples showing the effects.

• Virtual stake-driving to streamline construction: AR is effective even for traditional layout tasks such as stake-driving. Previously, positions were marked with wooden stakes or chalk, but placing virtual "stakes" in AR eliminates the need for physical stakes. By measuring the coordinates of stake positions indicated in the design with GPS and displaying virtual stakes or marks through a smartphone at those points, accurate positioning can be shown even on rock outcrops or steep slopes where physical stakes cannot be driven. At one site, confirming construction points while viewing design data overlaid in AR reduced rework from repeatedly laying out positions with paper plans and led to shorter meetings and reduced work time.

• Reproduction photography for regular inspections and improved efficiency: AR×GPS is useful for inspection of infrastructure as well. For example, in crack surveys at tunnel portals or slopes, it is necessary to reproduce the same viewpoint as the previous inspection for photographic comparison. Traditionally, technicians relied on experience to reproduce camera position and angle by comparing past photos with the site. With an AR-enabled surveying app, you can record the coordinates and camera orientation of the previous shot, and on-site the smartphone’s AR arrows and guides will lead you to the "same location and angle." In fact, LRTK smartphone apps display the angular difference with past photos numerically and change the frame to green when the misalignment reaches zero, making it immediately apparent when the same angle is reproduced. This system allows anyone to perform fixed-point observations easily, improving crack comparison accuracy and greatly reducing time spent on trial-and-error during shooting.

• Rapid survey data sharing in disaster response: AR×GPS is also helpful in initial emergency response. For example, immediately after heavy rain disasters, workers at a damaged site can instantly measure coordinates of necessary points with a smartphone and upload them to the cloud, while remote office engineers receive the data in real time and generate drawings. Processes that formerly required sending a survey team and creating maps now become "measure on-site and share immediately," dramatically accelerating damage assessment and recovery planning decisions. Thus, AR×GPS contributes significantly to operational efficiency not only during normal times but also in emergencies.

Benefits in Measurement, Construction, Inspection, and Maintenance Phases

AR×GPS is effective at all stages of civil and construction projects, from surveying to construction, inspection, and maintenance. Here are the main advantages in each phase.

• Surveying (measurement) phase: One person can perform high-precision measurements for field reference point surveys and as-built (quantity) measurements. RTK-GPS enables coordinate acquisition at centimeter-level accuracy, allowing site supervisors to handle surveying tasks that previously required skilled technicians, reducing personnel arrangements and scheduling burdens. As GPS can position even beyond obstructions, fewer measurements are missed in areas with poor sightlines, enabling efficient coverage of large sites. Acquired data can be shared to the cloud on the spot, smoothing handovers to subsequent processes.

• Construction phase: Positioning and dimensional verification on-site become intuitive. Project lines and finished heights from design drawings projected onto the ground via AR help workers and operators easily visualize the final form, preventing construction mistakes. Layout setup can be simplified or omitted, reducing rework and verification time for stake-driving. Displaying 3D BIM/CIM models in AR allows all stakeholders to share the completed image on-site, speeding meetings and consensus building.

• Inspection phase: As described above, AR guidance makes accurate comparisons with past data easy. On-site, you can precisely perform photography with the same framing and verify against previous measurements, helping prevent overlooking degradation and improving decision accuracy. Information can be unified across different inspectors, contributing to standardization and leveling of inspection tasks. Furthermore, if inspection results are digitized and recorded to the cloud on-site, report creation becomes more efficient and long-term asset management through accumulated data is enhanced.

• Maintenance phase: For maintenance of infrastructure such as roads and bridges, AR×GPS is a powerful tool. Combined with LiDAR-equipped iPhones/iPads, high-precision, georeferenced 3D point cloud data of the site can be acquired and used for monitoring changes over time and assessing as-built conditions. Overlaying point clouds from multiple time points enables quantitative evaluation of sediment accumulation or structural displacement, aiding priority decisions in maintenance planning. If AR displays past repair histories or underground utility locations on-site, workers can respond quickly and safely. In this way, AR×GPS contributes to advanced data utilization and faster decision-making even in the maintenance phase.

Ease of Adoption and Compatibility with Digitalization

Introducing new technology on-site can seem daunting or costly, but AR×GPS surveying also boasts a low adoption barrier. The required hardware is a standard smartphone and a small high-precision GNSS receiver. No special surveying instruments or dedicated server equipment are necessary, and operation is done on a smartphone familiar to most workers. Positioning and recording can be performed by simply following an intuitive app UI and pressing buttons; the system is designed to be usable without complicated settings or specialist knowledge. It is easily accepted by both young and veteran staff, minimizing training costs.

One solution that makes AR×GPS easy to realize is LRTK. LRTK consists of a smartphone-mounted high-precision GPS device (receiver), a surveying app, and cloud services; by attaching a pocket-sized device to a smartphone, anyone can immediately start using centimeter-level positioning and AR functions. The compact device weighs only about 165 g and has a thickness of about 13 mm (0.51 in), with an internal battery and antenna in a single integrated, portable unit, making it realistic to use as a "one-per-worker site tool." Despite its high precision, the price is kept affordable, allowing adoption on a limited budget. In fact, purchasing a single unit can lead to short payback periods through reduced time waiting for surveying and lower costs for outsourcing surveys.

LRTK also suits a small-start approach. You can begin with small projects or limited processes, letting site staff experience usability and benefits while gradually expanding use. With cloud integration, data is automatically shared and stored, making digital linkage with other systems (CAD, BIM, construction management software, etc.) smooth. Paper forms and manual entry are reduced, and since data is electronic from the start, it aligns well with DX initiatives. On-site voices include, "Once you experience this convenience, you can't go back to the old way," making it a valuable investment for management in both productivity improvement and workstyle reform. The technology also aligns with industry DX trends promoted by the Ministry of Land, Infrastructure, Transport and Tourism, such as *i-Construction*, so introducing AR×GPS surveying has high compatibility with corporate digitalization strategies.

Future Development Potential

Surveying and construction support technologies using AR×GPS will continue to evolve. On the hardware side, AR displays currently implemented on smartphones and tablets may migrate to hands-free devices such as AR glasses (smart glasses) or helmet-integrated displays, projecting data directly into the worker’s field of view. That would allow essential information to be visible even while both hands are occupied, further improving efficiency and safety.

Positioning technology will also advance. If systems that achieve centimeter accuracy using satellite communications alone—like augmentation signals (CLAS) from Japan’s quasi-zenith satellite Michibiki—become widespread, stable positioning will be possible even in mountainous areas and remote islands where communication infrastructure is weak. Moreover, integrating multiple satellite constellations (GNSS) will improve positioning accuracy and reliability, and new solutions may appear for urban "GNSS positioning dead zones" and indoor spaces where high-precision positioning was previously difficult. For example, combining camera-based visual positioning (VPS) or 5G-based localization techniques could enable AR alignment inside tunnels and buildings, creating a comprehensive positioning network that seamlessly connects outdoors and indoors.

On the software side, AI could analyze the vast accumulated surveying data and inspection records to automatically detect anomalies and propose optimized construction plans. A future where AR devices display real-time alerts like "anomaly likely here" is conceivable. Additionally, if a digital twin of the entire construction site is managed in the cloud and synchronized with the field in real time, remote supervision such as checking and directing on-site work through AR from the office could become possible.

In this way, the wave of on-site DX driven by AR×GPS is expected to expand further. As technology advances, its applications may grow from measurement, construction, and maintenance to education and training, and even integration with autonomous construction systems. What now seems cutting-edge may well become commonplace within a few years, with AR-based surveying and drawing verification taken for granted. AR×GPS surveying, which can dramatically improve on-site efficiency and accuracy, will be a key technology to watch in the future of the construction and surveying industries.