CLAS-compatible LRTK Phone Enables Labor-saving Surveying Work: High-precision Positioning Even Outside Mobile Coverage

Table of Contents

• Current state and challenges of surveying work

• What is the LRTK Phone?

• High-precision positioning even outside mobile coverage with CLAS support

• Single-person survey workflows: Features of the LRTK Phone

• Use cases: from disaster response to infrastructure management

• Conclusion: the future opened by simplified surveying with LRTK

• FAQ

Current state and challenges of surveying work

Surveying work, indispensable for the maintenance of social infrastructure and construction sites, has several challenges in conventional methods. Typical surveying uses expensive instruments such as total stations (TS) and is generally carried out by two or more skilled operators. Recently popular GNSS surveying instruments that offer high precision are still large, expensive, and require specialized knowledge to operate. As a result, field surveying has required significant labor and cost, placing a heavy burden amid manpower shortages.

Main challenges pointed out in conventional surveying work:

• Large personnel burden: transporting and setting up heavy equipment requires multiple people, straining human resources.

• Equipment handling and maintenance: precision instruments require regular calibration and maintenance, and sending them to manufacturers for calibration involves time and hassle.

• Limits of GPS-only positioning: common GPS (GNSS) receivers or smartphone GPS can produce errors of about 5–10 m, making them unsuitable for surveying that requires high precision.

• Dependence on communications infrastructure: traditional RTK positioning requires correction data from base stations via the Internet, so high-precision positioning is difficult at sites without mobile coverage, such as mountainous areas.

Thus, even in situations that demand speed and precision, conventional methods involve a dilemma of time and manpower. In particular, surveying at disaster sites or remote locations has restrictions such as not being able to measure immediately when needed or having to wait for specialist contractors to arrive, hindering early recovery and efficient infrastructure management.

What is the LRTK Phone?

The LRTK Phone is a solution developed to address these challenges and realize labor-saving surveying. The LRTK Phone is a small, lightweight positioning device and system that works with a smartphone to enable centimeter-level (cm level accuracy (half-inch accuracy)) high-precision positioning. Although compact enough to fit in a pocket, it delivers accuracy comparable to conventional high-end GNSS surveying instruments.

Basic specs and features of the LRTK Phone:

• Smartphone-sized surveying device: With a lightweight, slim design of approximately 165g in weight and about 1 cm (0.4 in) thickness, it is literally portable with your smartphone. It’s easy to carry to the site and eliminates bulky tripods and mounting equipment.

• Centimeter-level (cm level accuracy (half-inch accuracy)) positioning accuracy: Equipped with a high-performance multi-GNSS receiver, RTK (real-time kinematic) technology enables astonishing accuracy of about 1–2 cm (0.4–0.8 in) horizontally and about 3 cm (1.2 in) vertically. This approaches the accuracy of first-class GNSS equipment used for national land surveying, and experiments have confirmed errors within a few millimeters in some cases.

• Smartphone integration: A dedicated smartphone app (currently supporting iPhone/iPad) connects to the device, allowing intuitive control of positioning start/stop, data recording, and other functions. Acquired coordinate data include latitude, longitude, and altitude information and can be confirmed in real time on the phone screen.

• Supports single-person operation: Surveying that used to require two people can be completed by one with the LRTK Phone. For example, height offset calculations that previously required an assistant are automatically corrected by the app when the device is mounted on a supplied monopod (pole). There is no need to have someone hold a prism, so being able to efficiently perform surveying alone is a major advantage.

• Built-in battery and long runtime: The LRTK Phone contains a rechargeable battery and can perform continuous measurements for about 6 hours. It can also be used while being powered from a mobile battery at the site, ensuring reliability during long work periods.

In this way, the LRTK Phone is a new surveying tool that combines “high-precision positioning,” “portability,” and “ease of operation.” It distinguishes itself from conventional surveying equipment by pursuing ease of use and portability while maintaining first-class instrument accuracy.

High-precision positioning even outside mobile coverage with CLAS support

One major feature of the LRTK Phone is that it supports the QZSS “Michibiki” CLAS service. CLAS (Centimeter-Level Augmentation Service) is the high-precision positioning augmentation signal provided by Japan’s quasi-zenith satellite system “Michibiki” (QZSS). Normally, high-precision GNSS positioning requires correction information from base stations, but CLAS delivers that correction data directly to users via satellite.

Because the LRTK Phone can receive CLAS signals, it can achieve centimeter-level (cm level accuracy (half-inch accuracy)) positioning even outside mobile phone coverage. For example, in forested mountain areas or construction sites on remote islands where mobile networks do not reach, high-precision positioning is possible using augmentation information from the Michibiki satellites. Even in areas where communication infrastructure is cut off immediately after a disaster, the LRTK Phone alone enables accurate on-site positioning, making it extremely useful for initial response.

Benefits of CLAS support:

• Reduced communication costs and hassle: There is no need to contract or use Internet-based RTK base station services, as everything can be completed using signals from satellites. This eliminates monthly service fees and the effort of installing base stations.

• Real-time capability: Because correction information is continuously broadcast from satellites, you can begin high-precision positioning on site without waiting. Simply attach the dedicated antenna and press “CLAS mode” in the app to automatically capture the augmentation signal and obtain a Fix solution (high-precision solution) within minutes.

• Usable nationwide in Japan: CLAS is designed to cover all of Japan (with multiple quasi-zenith satellites in orbit so that at least one is visible overhead at any time), so the same mechanism can be expected to provide high-precision positioning even in remote mountains within the country.

In fact, the revolutionary CLAS support of the LRTK Phone has been recognized and introduced as a use case on the official Michibiki site operated by the Cabinet Office. It is now being adopted by local governments and companies and is attracting attention as a “high-precision positioning tool usable even outside communication coverage.”

Single-person survey workflows: Features of the LRTK Phone

The LRTK Phone not only offers accuracy and portability but also includes various functions to enable a single person to complete surveying. These features allow tasks that previously depended on multiple people or specialist contractors to be performed by one field staff member, making labor-saving surveying a reality.

Here are the main functions and their benefits.

• High-precision single-point positioning: When the LRTK Phone is mounted on a monopod (pole), it can acquire precise coordinates of any point just like traditional GNSS surveying equipment. On the app, simply indicate the point you want to measure and press the measurement button; after several seconds of observation, the point’s latitude, longitude, and altitude are recorded. Height offsets (instrument height) are automatically corrected by the app, so you don’t need to worry about the pole length. This allows leveling-like tasks previously performed by surveyors to be easily substituted.

• 3D point cloud scanning: The LRTK Phone works with a smartphone’s (iPhone) built-in LiDAR scanner or camera to capture surrounding structures and terrain as 3D point cloud data. For example, large slopes such as cliffs or embankments can be scanned by holding up the smartphone for just 1–2 minutes to obtain high-density point cloud data. Since the acquired point clouds are assigned absolute coordinates (geodetic coordinates), it is easy to merge them later with other survey data or overlay them on design drawings. 3D surveying that previously required specialized equipment or drones can now be performed by anyone in a short time.

• On-site visualization with AR: The device includes a function to display precise positional information in AR (augmented reality) on the phone screen. For instance, 2D/3D design data (BIM/CIM models, etc.) can be overlaid onto the real-world site view with no positional offset for checking. This enables intuitive comparison of “plans on drawings” and “conditions on site,” and is powerful for marking construction locations and inspecting as-built conditions. Processes that used to require skilled workers to set out stakes or scribe lines can be streamlined with AR display, and sharing images with clients and stakeholders becomes easier.

• Cloud integration and data sharing: Data measured and recorded with the LRTK Phone can be uploaded from the phone to the LRTK Cloud (a dedicated cloud service) on site. On the cloud, recorded survey points, tracks, photos taken, and generated point cloud models can be viewed in 2D maps or 3D views. From an office PC via a browser, you can view site data, measure distances and areas, and share information with stakeholders, allowing you to grasp the situation and give instructions without visiting the site. This enables remote collaboration where the field person collects data alone and office managers or designers immediately verify and utilize it.

• Easy operation and automatic processing: The app interface is simple and easy to understand, allowing intuitive operation even for those unfamiliar with technical terms. Starting/stopping positioning and data synchronization are one-tap operations, and complex setting adjustments are automated. Cross-functional guidance and tutorials are also substantial, so “anyone can start using it after about 5 minutes of explanation.” This allows non-specialist field staff to carry out measurements themselves and helps alleviate the shortage of surveying technicians within organizations.

With these features, the LRTK Phone becomes not just a positioning device but a comprehensive tool supporting on-site digitization and efficiency. Tasks that used to require separate devices and software can be completed with a single smartphone plus the LRTK Phone, saving time and manpower and improving data consistency and accuracy.

Use cases: from disaster response to infrastructure management

The capabilities of the LRTK Phone are supported by various field use cases. Here we look at its benefits from two perspectives: disaster response and infrastructure maintenance/management.

1\. Rapid situational awareness at disaster sites In large-scale landslides or earthquake-damaged areas, quick situational assessment and recovery planning are required. Traditionally, survey teams traveled to the site to measure terrain and identify damage areas, which took time. In cases where the LRTK Phone was introduced, a single responsible person could go to the site immediately after a disaster, scan the surroundings, and instantly obtain high-precision 3D terrain data. For example, in Fukui City, Fukui Prefecture, a system using iPhones and the LRTK Phone was implemented for surveying disaster sites, contributing to early recovery and cost reduction. The precise data obtained on site were shared immediately via the cloud, allowing municipal offices and headquarters to grasp the situation and accelerate decisions such as recovery policies and deployment of heavy machinery. Initial response that previously took several days was dramatically shortened, helping prevent further damage and enabling timely information provision to residents.

2\. Use in infrastructure maintenance and routine inspections The LRTK Phone is also powerful in maintaining roads, bridges, slopes, and river facilities. Infrastructure managers need to know current dimensions and displacements for routine inspections and repair planning, but previously they often had to commission surveying companies or take time-consuming manual measurements. By equipping field personnel with the LRTK Phone, required locations can be measured and recorded immediately on site. For example, the depth and extent of road subsidence can be measured on site and shared via the cloud so managers can accurately understand the situation from the office. In slope deformation checks, comparing previously scanned point clouds with newly acquired data can detect slight soil movements or deformations. Abnormalities that might have been overlooked are represented numerically, improving the quality of preventive maintenance. Additionally, using the LRTK Phone’s AR function to visualize the positions of underground buried objects on site can help prevent accidental damage during excavation work.

As these cases show, the LRTK Phone is more than a tool for improving surveying efficiency; it is a platform that accelerates on-site problem solving and decision making. In disaster response it supports rapid initial actions that are directly connected to human lives, and in infrastructure management it helps monitor extensive assets with limited personnel.

Conclusion: the future opened by simplified surveying with LRTK

The CLAS-compatible LRTK Phone is changing conventional surveying by making “high-precision positioning available anywhere, to anyone.” With centimeter-level (cm level accuracy (half-inch accuracy)) precision even in remote mountains outside mobile coverage, and the ability for a single person to collect and share 3D site data, this workflow directly contributes to labor-saving surveying and brings overall efficiency and sophistication to operations.

Surveying has traditionally been a domain that had to be entrusted to specialists. As the concept of simplified surveying with LRTK spreads, it will become commonplace for field personnel to quickly obtain the data they need and use it for decision making. An era is approaching in which high-precision geospatial information can be used routinely without difficult settings or expensive equipment.

In industries such as infrastructure and construction, where labor shortages are becoming more serious, the LRTK Phone is a reliable partner that addresses these challenges through digital technology. Beyond labor and cost reductions, it contributes to improved on-site safety and the advancement of operations (for example, expanding into advanced data analysis). If simplified surveying with LRTK enables “surveying by anyone,” business processes themselves will be transformed, enabling faster and more accurate infrastructure management and construction.

The future opened by simplified surveying with LRTK is not limited to improved work efficiency. It seamlessly connects sites and data, visualizes previously unseen information, and creates new value. Now that high-precision positioning is no longer exclusive but accessible to everyone, why not bring its benefits to your site?

FAQ

Q. Can the LRTK Phone really achieve centimeter-level positioning? A. Yes. By combining RTK technology and satellite augmentation information, the LRTK Phone achieves about 1–2 cm (0.4–0.8 in) horizontal accuracy and about 3 cm (1.2 in) vertical accuracy. Comparisons measuring the same points with high-precision GNSS equipment have confirmed errors within a few millimeters in some cases. Therefore, it enables precise positioning that ordinary GPS cannot provide.

Q. How does it differ from a smartphone’s GPS? A. General smartphone GPS has errors of several meters, but the LRTK Phone uses a dedicated high-sensitivity GNSS antenna and a multi-frequency receiver. In addition, it reduces positioning errors significantly by using corrections such as CLAS from Michibiki and RTK corrections from other reference signals. In short, the major difference is an evolution from “single GPS positioning” to “high-precision positioning using multiple positioning references.”

Q. How does it achieve high-precision positioning where there is no mobile coverage? A. The LRTK Phone can directly receive the Michibiki CLAS signal, so it can perform high-precision positioning even where mobile signals do not reach. Usage is simple: at a site outside coverage, attach the dedicated antenna included in the starter kit to the LRTK Phone, select “CLAS mode” in the app, and wait a few minutes in an open-sky location. The device will receive augmentation information from satellites, stabilize positioning, and acquire the current position with centimeter-level (cm level accuracy (half-inch accuracy)) precision.

Q. Can people without specialized knowledge or skills use it? A. Yes. The LRTK Phone is designed to be operable by non-experts. The smartphone app is simple and easy to understand; starting/stopping positioning and saving data are one-tap operations. Complex calculations such as height correction and coordinate transformations are handled automatically by the app. Basic operation can be learned with short training, and many field staff say, “It was easier to use than I expected.”

Q. How can positioning data be utilized? A. Measured coordinate data and 3D point clouds can be uploaded to the cloud for utilization. Synchronized cloud data can be displayed as maps or 3D models on a PC browser for measuring distances and areas or comparing with drawing data. The surveying data obtained by the LRTK Phone are saved in the Japanese geodetic system (plane rectangular coordinate system), but the app or cloud can convert them to arbitrary coordinate systems (e.g., WGS84 or the new JGD2024). This allows smooth integration with traditional CAD drawings and GIS data.

Q. Do environmental conditions such as rain or forests affect positioning accuracy? A. Satellite positioning is affected by sky visibility. In environments where satellite visibility is obstructed, such as inside forests or under elevated structures, the LRTK Phone may take longer to position or experience degraded accuracy. Heavy rain or storms can also destabilize satellite signals due to ionospheric and atmospheric effects. However, the LRTK Phone is designed to use multiple satellite constellations (GLONASS, Galileo, etc.) in addition to GPS to capture as many satellites as possible, improving positioning success rates under difficult conditions. Although there are limitations due to weather and environment, it is expected to perform stably in a wider range of situations than conventional equipment.

Q. What is needed to introduce the LRTK Phone? A. Basically, you can start with the LRTK Phone device and a compatible iPhone or iPad. Setup is easy: install the dedicated app from the App Store and pair the LRTK Phone with the smartphone via Bluetooth or Lightning connection. Antennas and a monopod (pole) necessary for positioning are included in the starter kit, so you can begin surveying on the day it arrives. No special licenses or qualifications are required for introduction, and operational training is brief.

Q. Is it a problem if users do not have national qualifications such as a licensed surveyor? A. For in-house measurements and construction management using the LRTK Phone, it can be used without special qualifications. The achievable accuracy is comparable to national standards and is sufficient for many practical tasks. However, please note that services defined as “public surveying” by law, such as acceptance checks for public works or control point surveys, must be performed under the supervision of a licensed surveyor. Nevertheless, for general private-sector work and routine surveying tasks, the LRTK Phone can improve efficiency regardless of whether users hold specific qualifications.