Table of Contents

• Current State and Challenges of Survey Work

• What Is an LRTK Phone?

• High-Precision Positioning Outside Cell Coverage with CLAS Support

• Features That Enable One-Person Survey Work: LRTK Phone Highlights

• Use Cases: From Disaster Response to Infrastructure Management

• Summary: The Future Opened by Simple Surveying with LRTK

• FAQ

Current State and Challenges of Survey Work

Surveying is indispensable for maintaining social infrastructure and at construction sites, but traditional methods have several challenges. Typical surveys employ expensive equipment such as total stations (TS) and are generally conducted by two or more skilled workers. Recently popular GNSS surveying instruments that provide high accuracy are often large, expensive, and require specialist knowledge to operate. As a result, on-site surveying has required significant labor and cost, placing a heavy burden amid workforce shortages.

Main challenges pointed out in conventional surveying:

• High personnel burden: Heavy equipment requires multiple people to transport and set up, straining human resources.

• Handling and maintenance of equipment: Precision instruments need regular calibration and maintenance, and sending them to manufacturers for calibration involves time and effort.

• Limits of GPS-only positioning: Typical GPS (GNSS) receivers or smartphone GPS can have errors of about 5–10 m (16.4–32.8 ft), making them unsuitable for high-precision surveying.

• Dependence on communications infrastructure: Traditional RTK positioning requires receiving base station correction data via the internet, so high-precision positioning is difficult at sites without cellular coverage, such as mountain areas.

Thus, even where speed and precision are required, traditional methods involve a dilemma of time and personnel. Especially in disaster sites and remote areas, there are constraints such as not being able to measure immediately when needed or having to wait for specialist contractors to arrive, hindering rapid recovery and efficient infrastructure management.

What Is an LRTK Phone?

To solve these issues and enable labor reduction in surveying, the LRTK Phone has emerged. LRTK Phone is a compact, lightweight positioning device and system that works with a smartphone to enable centimeter-level high-precision positioning. Despite fitting in a pocket, it delivers accuracy comparable to conventional high-end GNSS surveying instruments.

Basic specs and features of the LRTK Phone:

• Survey instrument the size of a smartphone: Designed as a thin, lightweight device weighing about 165 g, with a thickness of about 1 cm (0.4 in), it can literally be carried together with a smartphone. It’s easy to bring to sites and eliminates the need for bulky tripods and mounting equipment.

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

• Smartphone integration: A dedicated smartphone app (currently supports iPhone/iPad) connects to the device, allowing intuitive control of positioning start/stop, data recording, and various functions. Acquired coordinate data includes latitude, longitude, and height information, which can be viewed in real time on the smartphone screen.

• Supports solo operation: Surveys that used to require two people can be completed by one person with 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 pole. There’s no need for someone to hold a prism, so one person can efficiently perform surveys, which is a major advantage.

• Built-in battery and long operation time: The LRTK Phone itself contains a rechargeable battery and can perform continuous measurements for about 6 hours. It can also be used while powered from a mobile battery on site, providing reassurance for long work sessions.

In this way, the LRTK Phone is a new surveying tool that combines “high-precision positioning,” “portability,” and “ease of operation.” By securing accuracy comparable to Class-1 instruments while emphasizing usability and transportability, it sets itself apart from traditional surveying equipment.

High-Precision Positioning Outside Cell Coverage with CLAS Support

A major feature of the LRTK Phone is that it supports the CLAS service of the QZSS ("Michibiki") quasi-zenith satellites. CLAS (Centimeter-Level Augmentation Service) is a high-precision positioning augmentation signal provided by Japan’s QZSS. Normally, high-precision GNSS positioning requires correction information from ground 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 positioning even outside cellular coverage. For example, in forested mountain areas or construction sites on remote islands where mobile networks are unavailable, high-precision positioning is possible using augmentation data from Michibiki satellites. Even immediately after a disaster when communications infrastructure has been cut, 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 subscribe to or use internet-based RTK base station services; satellite signals suffice. This eliminates monthly service fees and the effort of setting up base stations.

• Real-time capability: Because correction information is continuously broadcast from satellites, high-precision positioning can start on site without waiting. Simply attach the dedicated antenna, press “CLAS mode” in the app, and the device will automatically acquire augmentation signals and obtain a Fix solution within minutes.

• Available nationwide in Japan: CLAS is designed to cover the entire country (multiple quasi-zenith satellites in orbit ensure that at least one is visible), so high-precision positioning can be expected even in remote mountain locations within Japan.

In practice, the LRTK Phone’s CLAS-compatible technology has been recognized and featured as a use case on the official Michibiki site run by the Cabinet Office. Adoption is progressing among local governments and companies, and it’s gaining attention as a “high-precision positioning tool usable even outside cellular coverage.”

Features That Enable One-Person Survey Work: LRTK Phone Highlights

Beyond accuracy and portability, the LRTK Phone includes various functions that allow a single person to complete surveying tasks. These functions enable field personnel to perform work that previously required multiple people or specialist contractors, making labor reduction in surveying a reality.

Let’s look at the main functions and their benefits.

• High-precision single-point positioning: Mounting the LRTK Phone on a pole lets you obtain coordinates of arbitrary points with high precision, similar to conventional GNSS survey instruments. On the app, simply indicate the point to measure and press the measurement button; after a few seconds of observation, the point’s latitude, longitude, and height are recorded. The app automatically corrects for instrument height (pole length), so you don’t need to worry about the pole length. This allows easy substitution for leveling-like tasks traditionally performed by surveyors.

• 3D point cloud scanning: The LRTK Phone can work 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 waving the smartphone for about 1–2 minutes to obtain high-density point clouds. Because the acquired point clouds are tagged with absolute coordinates (geodetic coordinates), they can be easily combined with other survey data or overlaid on design drawings later. 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 AR (augmented reality) display functionality that leverages high-precision position information. For instance, 2D/3D design data (BIM/CIM models, etc.) can be overlaid on the site view on the smartphone screen and checked with accurate alignment. This enables intuitive comparisons between the “plan on paper” and the “actual site,” helping with marking construction points and checking as-built conditions. Tasks that used to require experienced personnel for setting out can be simplified with AR, making it easier to share visual information with owners and stakeholders.

• Cloud integration and data sharing: Data measured and recorded with the LRTK Phone can be uploaded from the smartphone to the LRTK Cloud (a dedicated cloud service). On the cloud, recorded points, tracks, photos, and generated point cloud models can be reviewed 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, enabling situation assessment and issuing instructions without visiting the site. This enables remote collaboration where field personnel collect data solo and office managers or designers immediately verify and utilize it.

• Simple operation and automatic processing: The app interface is simple and intuitive so even users unfamiliar with technical terms can operate it. Starting/stopping positioning and data sync are one-tap actions, and complex settings are automated. Cross-functional guidance and tutorials are provided, and most users can start using it after about 5 minutes of instruction. This lets non-specialist field staff perform measurements, helping mitigate the shortage of survey technicians within organizations.

With this suite of functions, the LRTK Phone is more than just a positioning device—it is a comprehensive tool that supports on-site digitalization and efficiency. By consolidating tasks that used to require multiple devices and software into one smartphone + LRTK Phone setup, it saves time and labor while improving data consistency and accuracy.

Use Cases: From Disaster Response to Infrastructure Management

The capabilities of the LRTK Phone are supported by a range of real-world use cases. Here we examine its advantages from two perspectives: disaster response and infrastructure maintenance and management.

• Rapid situational awareness at disaster sites At sites of large landslides or earthquake damage, quick situational assessment and recovery planning are essential. Traditionally, survey teams needed time to arrive on site to measure terrain and delineate affected areas. In cases where the LRTK Phone was introduced, a single responder 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 an iPhone and LRTK Phone was implemented for surveying damaged sites, contributing to faster recovery and cost reduction. Precise data collected on site was shared via the cloud, allowing municipal offices and headquarters to grasp the situation immediately and accelerate subsequent actions such as deciding recovery policies and dispatching heavy equipment. Initial response that once took several days was drastically shortened, helping prevent further damage and enabling timely information provision to residents.

• Use in infrastructure maintenance and routine inspections LRTK Phone is also powerful for maintaining roads, bridges, slopes, and river facilities. Infrastructure managers need to know current dimensions and displacements for periodic inspections and repair planning, but until now they often had to contract survey firms or perform time-consuming manual measurements. Equipping field personnel with LRTK Phone allows them to measure and record needed points on the spot. For example, the depth and extent of a road subsidence can be measured on site and shared via the cloud so managers can accurately assess the situation from the office. For slope deformation checks, comparing previously scanned point clouds with newly acquired data can detect subtle soil movement or deformation. Abnormalities that might have been overlooked are expressed numerically, improving the quality of preventive maintenance. Additionally, using LRTK Phone’s AR function to visualize underground utility positions on site can help prevent accidental damage during excavation.

As these examples show, LRTK Phone is not merely a tool for improving survey efficiency; it becomes a platform that solves on-site problems and speeds decision-making. In disaster response, it supports life-critical rapid actions, and in infrastructure management, it empowers limited personnel to monitor extensive assets.

Summary: The Future Opened by Simple Surveying with LRTK

CLAS-compatible LRTK Phone is transforming conventional surveying by making “high-precision positioning anywhere, by anyone” a reality. Centimeter accuracy is achievable even in remote mountain areas without cell coverage, and a single worker can complete workflows from 3D data collection to sharing on site—this directly reduces labor in surveying and brings overall operational efficiency and sophistication.

Surveying has traditionally been a domain entrusted to specialists. But as the concept of simple surveying with LRTK spreads, it will become commonplace for field personnel themselves 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 complex settings or expensive equipment.

Amid growing labor shortages in infrastructure and construction industries, LRTK Phone is a reliable partner that leverages digital technology to address these challenges. Beyond labor and cost savings, it contributes to improved site safety and advanced operations (such as downstream data analytics). If LRTK enables “surveying anyone can do,” business processes themselves will transform, enabling faster and more accurate infrastructure management and construction.

The future opened by simple surveying with LRTK is not limited to productivity gains. It seamlessly connects field sites and data, visualizes previously unseen information, and creates new value. Now that high-precision positioning is no longer exclusive, 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 approximately 1–2 cm (0.4–0.8 in) horizontal accuracy and about 3 cm (1.2 in) vertical accuracy. Comparisons with high-precision GNSS instruments at the same points have shown 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 GPS? A. Typical smartphone GPS can have errors of several meters, whereas the LRTK Phone uses a dedicated high-sensitivity GNSS antenna and multi-frequency receiver. In addition, it uses corrections such as CLAS from Michibiki and other reference signals (RTK corrections) to greatly reduce positioning error. In short, it evolves from single GPS positioning to high-precision positioning using multiple positioning references.

Q. How does it achieve high-precision positioning outside cellular coverage? A. The LRTK Phone can directly receive CLAS signals from the QZSS Michibiki satellites, so it can perform high-precision positioning even where cellular signals are absent. In such areas, attach the dedicated antenna included in the starter kit to the LRTK Phone, select “CLAS mode” in the app, and in an open sky wait a few minutes to receive augmentation information from satellites. Positioning will stabilize and centimeter-level accuracy will be obtained.

Q. Can people without specialist knowledge or skills use it? A. Yes. The LRTK Phone is designed to be usable by non-specialists. The smartphone app is simple and easy to understand; starting/stopping positioning and saving data are one-tap operations. The app automatically handles height corrections and coordinate transformations. Basic operations can be learned in a short training session, and many field staff report that “it was easier to use than expected.”

Q. How can positioning data be utilized? A. Measured coordinates and 3D point cloud data can be uploaded to the cloud for utilization. Cloud-synced data can be displayed as maps and 3D models in a PC browser, allowing distance/area measurements and comparisons with drawing data. LRTK Phone stores survey data in the Japanese geodetic system (Plane Rectangular Coordinate System), but the app and cloud can convert to arbitrary coordinate systems (e.g., WGS84 or the new JGD2024). This enables smooth integration with existing CAD drawings and GIS data.

Q. Do environment and weather affect positioning accuracy, such as in rain or in forests? A. Satellite positioning depends on sky visibility. In environments where satellite visibility is obstructed, such as inside forests or under overpasses, the LRTK Phone may take longer to achieve positioning or accuracy may decrease. During heavy rain or storms, ionospheric and atmospheric conditions can destabilize satellite signals. However, LRTK Phone uses multiple satellite constellations (GLONASS, Galileo, etc.) in addition to GPS, capturing as many satellites as possible to increase positioning success under difficult conditions. While environmental and weather constraints exist, LRTK Phone is designed to provide stable positioning in a wider range of conditions than conventional equipment.

Q. What is required to introduce the LRTK Phone? A. Basically, you need the LRTK Phone unit and a compatible iPhone or iPad to get started. Setup is easy: install the dedicated app from the App Store and connect the LRTK Phone to your smartphone via Bluetooth or Lightning. Antennas, a pole, and other positioning accessories are included in the starter kit, so you can begin surveying the day the kit arrives. No special license or qualification is required, and training can be completed in a short time.

Q. Is it a problem if I don’t have national qualifications like a licensed surveyor? A. For internal measurements and construction management within your own company, you can use the LRTK Phone without special qualifications. Its achievable accuracy is comparable to national standards and is suitable for many practical uses. However, be aware that legally defined “public surveying” tasks such as construction acceptance inspections or control point surveys require work to be performed under the supervision of licensed surveyors. Nonetheless, for general private-sector work and everyday surveying tasks, LRTK Phone can improve efficiency regardless of qualification status.