Site burdens and personnel challenges faced by surveyors

Surveying work, indispensable on construction sites, has traditionally placed a heavy burden on technical staff, including surveyors. Generally, surveying has been performed by two or more people: one person operates the surveying instrument while another stands at the survey point holding a staff. This arrangement has persisted for many years, meaning that multiple personnel are required for a single survey, and planning staff and coordinating work schedules can be a frequent challenge. In addition, the physical burden of transporting and setting up heavy equipment in harsh environments such as mountainous or sloped terrain, and the fatigue from long hours of work under intense sun or in cold regions, have posed significant stresses for surveyors.

Furthermore, the construction industry is currently experiencing chronic labor shortages and an aging workforce, and the number of people who can perform surveying is declining. As veteran surveying technicians reach retirement and leave the field while fewer young entrants join, the average age of surveyors is rising each year. As a result, those who can "perform surveying" have become valuable, and the burden on each individual has increased. There are cases where limited personnel must cover multiple sites, or where other work is interrupted while waiting for surveying, making productivity improvement a major issue.

To solve these site burdens and personnel challenges, improving the efficiency of surveying work and achieving labor reduction (reduction of required manpower) is essential. In particular, there is growing expectation for new technologies and workflows that allow surveying to be "completed by one person." If measurements can be taken immediately at the required place and time, the time spent waiting for a survey crew is reduced and losses from stopping heavy machinery or other work can be minimized. In an era of labor shortages, the surveying field also needs transformation so that sites can be managed with small teams.

The possibility of surveying completed with a smartphone

Traditional surveying brings to mind expensive, specialized equipment such as total stations and GPS survey instruments. However, in recent years, improvements in smartphone performance and advances in positioning technology have made the prospect of "completing surveys with a smartphone" increasingly realistic. Smartphones are already widely used on sites and contain a variety of sensors such as cameras, accelerometers, and GPS. By combining these with high-precision positioning attachments and dedicated apps, surveying tasks that once required specialized instruments can increasingly be performed with just a smartphone.

This trend is also driven by the digitalization and ICT utilization of construction sites promoted by initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction. As efficient practices using new technologies—such as photogrammetry from drones and point cloud measurement by 3D laser scanners—become more common, smartphone surveying is attracting attention as one component of that shift. If the smartphone in your hand can become a high-precision surveying instrument without carrying special equipment, the way work is done on site will change dramatically. Technological progress is overturning the conventional wisdom that “surveying requires large equipment and multi-person teams,” and one symbol of this shift is smartphone surveying devices like the LRTK Phone.

Technical features and operation flow of the LRTK Phone

LRTK Phone is a smartphone-mounted RTK positioning device developed by Refyxia, a startup originating from Tokyo Institute of Technology. By simply attaching an ultra-compact RTK-GNSS receiver to a dedicated smartphone case with one touch, an iPhone or iPad instantly becomes a versatile surveying instrument with centimeter-level accuracy (cm level accuracy (half-inch accuracy)). Compact enough to fit in a pocket and weighing approximately 150 g, it is light enough to carry at all times and quickly take out for measurements when needed. It has a built-in battery and antenna, allowing one-handed operation without complicated wiring or external power sources.

The operation flow is also simple and intuitive. First, attach the LRTK Phone unit to the smartphone and launch the dedicated app. When powered on it begins acquiring GNSS satellites and becomes ready for high-precision positioning using the RTK method. Where network connectivity is available, it can receive correction data from reference stations and start positioning immediately. In areas without mobile signal, such as mountainous regions, it supports the centimeter-level augmentation service (CLAS) provided by Japan’s Quasi-Zenith Satellite System, Michibiki (cm level accuracy (half-inch accuracy)), enabling high-precision positioning even outside internet coverage. After positioning begins, select the mode suited to your purpose in the app—such as “record current position,” “point measurement,” “continuous measurement,” or “start guidance”—and follow the on-screen instructions. For example, in point measurement mode, pressing a button at the desired point records the latitude, longitude, and elevation at that instant. Measurement data automatically includes metadata such as time and satellite reception status, eliminating the need to take paper notes on site.

Measured data is not only saved on the smartphone but can also be uploaded to the cloud with a single tap for sharing. By sending data to the LRTK dedicated cloud service, staff in the office or clients can instantly access the information. Uploaded survey points are plotted on a map, and coordinate values and notes for each point can be viewed. Measurement data can also be exported as CSV or in the Ministry of Land, Infrastructure, Transport and Tourism’s SIMA format, allowing smooth import into design software and CAD. The ability to share information in the cloud directly from the field and greatly reduce post-field office data processing is another major advantage of adopting the LRTK Phone.

Main functions

• RTK positioning: LRTK Phone uses Real-Time Kinematic (RTK) methods to determine positions with errors down to a few centimeters. By combining satellite signals with correction data from reference stations, it acquires high-precision global coordinates (World Geodetic System) and plane rectangular coordinates. It stands apart from conventional smartphone built-in GPS with meter-level errors, providing field accuracy comparable to surveying instruments.

• AR (augmented reality): By combining high-precision position information with 3D design data, virtual objects or drawings can be overlaid on the smartphone screen. For example, if the positions of buried pipes are pre-scanned, the pipe models can be displayed as AR during subsequent excavations so anyone can avoid underground utilities accurately while working. Virtual objects remain fixed in the correct position even while walking around, aiding verification of as-built conditions and consensus-building with clients.

• Coordinate guidance: This function guides the user to a specified target coordinate. Arrows and distance information are shown on the smartphone screen, and alerts are provided by sound or display as you approach the target point. This makes it easy to find pile-driving positions or reference points shown on design drawings in the field. Tasks that previously required experienced intuition or instrument-based staking can be handled by less experienced workers using the guidance function.

• Point cloud acquisition: Using the smartphone camera or a LiDAR scanner (on supported devices), you can scan the surrounding environment and acquire 3D point cloud data. LRTK Phone can tag acquired point clouds with high-precision positional coordinates, producing point clouds with absolute coordinates that can be used directly in survey drawings and terrain models. Operation is simple—point the camera and walk—and large areas can be scanned in a short time. From the resulting point cloud data you can measure distances and areas or calculate volumes (earthwork) on the cloud. Data output that conforms to the Ministry of Land, Infrastructure, Transport and Tourism’s as-built management guidelines means it can be submitted as official as-built deliverables.

• Photo logging: LRTK Phone is also powerful for photo documentation of site conditions. Regular smartphone photos suffer from large GPS errors, and in places with poor signal such as tunnels or under bridges, accurate location logging is impossible. With LRTK Phone, each photo can be tagged with centimeter-level coordinates and orientation information when taken (cm level accuracy (half-inch accuracy)). For example, when documenting disaster damage or photographing damage during bridge inspections, the exact location where each photo was taken can be demonstrated, which is extremely helpful for later analysis and sharing.

Use cases

• Pile-driving work: In foundation work, LRTK Phone’s coordinate guidance function is powerful for locating pile-driving positions. If the center position data of piles specified in the design drawings are input into the app, workers can simply follow the on-screen guidance to find the required location. This reduces the need for surveyors to set up batter boards or perform marking, enabling efficient pile centering by a single person. It can also be used to find survey stakes obscured by vegetation or reference points under snow, shortening work time.

• As-built verification: Smartphone surveying is useful for verifying as-built conditions in earthworks. Scanning development sites, embankments, and excavation areas with LRTK Phone allows quick acquisition of accurate 3D models of the finished terrain. Overlaying these with the design 3D model makes it easy to check at a glance whether the result matches the design. Deviations are shown as color-coded heat maps, allowing immediate identification of overfill or undercut areas. Point cloud data can automatically calculate embankment and excavation volumes, instantly reflecting quantity management and as-built documentation—drastically streamlining processes that previously took days.

• Disaster response: Smartphone-based surveying is extremely useful at disaster sites caused by earthquakes or heavy rain. In emergencies when large-scale surveying equipment cannot be deployed, a pocket-sized LRTK Phone can provide situational awareness. For example, at a large landslide site where rapid sharing of damage information is needed, scanning the collapsed terrain with LRTK Phone and uploading to the cloud allows the office or disaster response headquarters to immediately view 3D data. Even when communication infrastructure is disrupted, surveying using satellite augmentation information is possible, supporting initial surveys in isolated areas. In fact, during the Noto Peninsula earthquake, reports indicate that LRTK Phone was effective in field investigations, enabling small teams to efficiently record damage.

• Infrastructure inspection: Smartphone surveying technology is applied to routine inspections of infrastructure such as bridges, tunnels, water pipes, and power facilities. When inspectors take photos with LRTK Phone, the longitude, latitude, and elevation are recorded, allowing accurate tracking of “which point” a photo corresponds to later. For measurements at height or in hazardous locations, remote positioning functions allow coordinates to be obtained from a safe distance, reducing the need for unsafe postures or working at height. This contributes to both labor savings and improved safety in infrastructure maintenance. Centralized cloud management of inspection history also streamlines analysis of changes over time and planning for repairs.

• Maintenance and other uses: LRTK Phone is expected to be useful across a wide range of infrastructure maintenance tasks such as roads and railways. For example, scanning and recording the locations of buried utilities during normal operations reduces the risk of damaging underground facilities during construction. It can also be applied to forestry and farmland management, enabling small teams to collect terrain data over large areas. Leveraging the ease of surveying with a smartphone, innovative use cases are expanding across various fields.

Differences from traditional methods and labor-reduction effects

Smartphone surveying with LRTK Phone differs from traditional surveying methods in several revolutionary ways. First and foremost is the change in personnel structure. Traditionally, multiple people were required for surveying tasks, but with smartphone surveying one person can complete the work, producing significant labor-reduction effects. Beyond reducing labor costs, this increases flexibility in personnel allocation, allowing staff to be reassigned to other important tasks. Especially in today’s environment of skilled labor shortages, it is difficult to “secure an extra person for surveying.” If each worker carries an LRTK Phone, they can measure immediately when needed, improving overall site productivity.

Next, the difference in mobility and ease of use is also noteworthy. Setting up and packing a total station takes time, and GNSS survey instruments require setup and transportation of large antennas. Precision instruments also often require specialized knowledge to operate, making them difficult for non-experts. By contrast, LRTK Phone requires little time to attach and launch the app, allowing you to start surveying the moment you decide to. The intuitive UI of the smartphone app enables those with limited expertise to operate it easily, and the app guides users to reduce measurement mistakes. The mobility to obtain high-precision data at the exact moment you want to measure is a strength not found in traditional methods.

Furthermore, the smooth digital integration of collected data is a major difference. Conventional surveying often involves analog steps such as handwritten field books or data transfer via USB memory. With smartphone surveying, data is digital from the start and saved/shared in the cloud, eliminating transcription errors and data entry work back at the office. Real-time exchange of information between the field and the office can accelerate the PDCA cycle of construction management.

The labor-reduction effects arising from these differences are not limited to reducing the number of survey personnel. Across the site, idle time for heavy machinery while waiting for surveying is reduced, shrinking opportunity losses from halted work. Time and effort required to confirm and share survey results are also reduced, improving communication among stakeholders and preventing rework. In short, introducing LRTK Phone promotes overall site efficiency and can be a trump card for achieving maximum results with limited personnel.

Future prospects

The arrival of LRTK Phone, which enables smartphone-based surveying, is bringing major changes to how surveying is done. If such one-device-per-person surveying devices become widespread, the digital twin of construction sites will advance further. With the ability to record and share high-precision data from the site in real time, processes that have long consumed personnel and time in construction and quality management could be dramatically streamlined. In the future, every worker on site may carry a surveying device and be able to collect data with surveyor-level accuracy whenever needed. This does not mean surveyors will become unnecessary; rather, surveying specialists will guide the entire site while routine measurements are handled autonomously by each person. Specialists can then focus resources on higher-level analysis and planning, helping to maintain and improve site capabilities despite labor shortages.

Technically, smartphone surveying is expected to evolve further. For example, RTK positioning currently achieved by combining smartphones with external devices may eventually be realized by high-precision chips built into smartphones (in fact, some latest smartphones are beginning to include chips that support high-precision positioning). Integration with AR glasses could create new interfaces where surveying information is displayed in the worker’s field of view without holding a smartphone. Cloud-based AI analyzing accumulated point cloud data and photos to support automatic anomaly detection and progress management is another anticipated application. Triggered by LRTK Phone, the DX (digital transformation) of construction sites is expected to accelerate further.

Conclusion

As a solution to the on-site burdens and manpower issues that have troubled surveyors, the idea of surveying that can be completed with a smartphone is very attractive. LRTK Phone, as a representative example, brings centimeter-level accuracy via RTK positioning and a variety of measurement and recording functions to smartphones, creating a “versatile on-site surveying instrument” usable by anyone. This enables surveying tasks that previously required two people to be performed by one person, opening a path to maintaining productivity even at sites struggling with labor shortages.

The important point is to integrate new technologies into site workflows. Even sites accustomed to traditional methods will be surprised by the ease and accuracy once they experience smartphone surveying. You may think, “Is it really okay to measure this easily?”—but that is the benefit of the latest technology. By leveraging the knowledge and experience of surveyors and mastering the LRTK Phone as a tool, the value of surveying work itself should increase.

The era when on-site surveying can be completed with a smartphone is just around the corner. Surveying professionals and construction managers struggling with labor shortages and efficiency should consider adopting this new option. Simple surveying with LRTK is sure to be a driving force in advancing how work is done on site.