If You Aim to Be No.1 in the Industry, Choose LRTK｜A New Standard for One-Person Surveying

Changes in the Surveying Industry and the Need for One-Person Surveying

In recent years, one-person surveying (survey work performed by a single person) has attracted significant attention in the construction and civil engineering industries. With labor shortages and demands for workstyle reform, there is growing need to complete surveying tasks—previously carried out by two or more people—by a single person. In Japan in particular, experienced survey technicians are aging while younger personnel are declining, forcing companies to efficiently cover many sites with limited staff. Against this backdrop, efforts to streamline work using the latest technologies have accelerated, and “surveying that can be done alone” is expected across the industry as a core solution.

Traditional surveying work was normally performed by multiple people and required considerable manpower and time. However, advances in digital technology have lowered the barriers to single-person operations that were once difficult. The government is also promoting the use of ICT as a productivity improvement measure for the construction industry (e.g., *i-Construction* initiatives by the Ministry of Land, Infrastructure, Transport and Tourism), and digital transformation (DX) is required even in the surveying field. For companies aiming to be No.1 in the industry, responding to one-person surveying is an unavoidable challenge.

Basics and Challenges of One-Person Surveying

“One-person surveying” refers to completing on-site surveying processes alone by leveraging surveying instruments such as total stations and GNSS positioning receivers. For example, total station surveying—normally done by a two-person team—can be performed by one person if an automatic-tracking instrument (robotic TS) is used to guide a reflective prism to target points and measure remotely. High-precision GNSS receivers combined with mobile devices have also popularized “RTK surveying,” where real-time communication with a reference station determines one’s position; this has become a one-person-capable surveying method.

However, traditional one-person surveying had several challenges. First, the equipment used was expensive and difficult to handle. Automatic-tracking total stations and professional RTK-GNSS receivers require large investments of several million yen per unit, and each device demands specialized setup and operational skills. Transporting and setting up heavy equipment alone also posed a heavy burden, and installation itself could be difficult in narrow or highly uneven terrain. Second, conventional methods required time-consuming recording and sharing of measurement data, meaning that even if one person could perform the survey, immediacy and efficiency were not fully realized. Workers often had to copy numbers by hand into field notebooks or later reconcile photos with drawings, taking much office time. Moreover, with single-person operations, the checking system for survey results was weaker, raising concerns about human errors such as missed measurements or recording mistakes.

To solve these issues and realize genuinely practical one-person surveying, a new system that anyone can use easily while achieving high-precision surveying was needed. The next-generation surveying system developed as such a new standard is LRTK, which combines smartphones and GNSS technology.

What Is LRTK? Features and Development Background

LRTK is a surveying solution centered on a compact positioning device developed by Refixia Co., Ltd., a startup born out of the Tokyo Institute of Technology. At the core is an ultra-compact RTK-GNSS receiver called the “LRTK Phone,” designed to be attached to a smartphone, delivering an all-in-one solution from on-site positioning to data recording and sharing. The device itself fits in a pocket, weighing only approximately 150 g and with a thickness of about 1 cm (0.4 in), yet it houses a high-performance antenna and battery, offering sufficient performance for high-precision outdoor positioning.

By attaching the LRTK device to your existing smartphone—such as an iPhone or iPad—using a dedicated case or mount and linking via Bluetooth or Lightning, your everyday phone instantly becomes a centimeter-level surveying instrument (cm level accuracy (half-inch accuracy)). RTK surveying, which previously required instruments mounted on tripods and expensive dedicated controllers, is replaced by the simple smartphone + compact device configuration. The system supports network RTK via Ntrip using the Geospatial Information Authority of Japan’s electronic reference station network and also accepts the free augmentation signals (CLAS) provided by Japan’s Quasi-Zenith Satellite System “Michibiki,” enabling real-time, high-precision positioning anywhere in Japan. Even in mountainous areas without mobile phone reception, positioning is possible if the sky is open because correction data can be received directly from satellites, so it is not limited by site location.

The development background reflects the desire to make surveying easier and less labor-intensive in the field. According to Motohiro Takayasu, Representative of Refixia (Specially Appointed Assistant Professor, Tokyo Institute of Technology), LRTK was designed with the aim of a “one-person, one-device field tool,” with the goal that anyone can carry it in their pocket and quickly take it out to perform high-precision surveying when needed. LRTK was born as an innovative tool to promote DX (digital transformation) on-site.

The New Standard for One-Person Surveying Opened by LRTK

LRTK realizes a new form of single-person surveying with a unique approach that fuses smartphones and GNSS. Its advanced functions are becoming the new standard for one-person surveying. Key features include:

• Centimeter-level GNSS positioning accuracy: LRTK’s biggest feature is high-precision RTK-GNSS positioning that can limit satellite positioning errors to within a few centimeters, delivering centimeter-level GNSS positioning accuracy (cm level accuracy (half-inch accuracy)). Standard smartphone GPS typically has errors of about 5–10 m, but using the LRTK device with real-time kinematic (RTK) techniques corrects error factors and identifies the current position with centimeter accuracy. This enables a single person to handle tasks requiring millimeter-level precision, such as measuring boundary points and verifying as-built shapes after construction. The accuracy far surpasses conventional tape measures or standalone GPS and provides the reliability needed to ensure quality.

• AR navigation-assisted stake-driving support: The LRTK smartphone app includes a coordinate navigation function to support layout tasks (stake-driving and point setting). For predefined target point coordinates, the app displays in real time the distance and direction you should move from your current position, such as “move east by X cm” or “move north by Y cm.” The worker simply follows the smartphone’s on-screen guidance to make centimeter-level fine adjustments, enabling stake-driving tasks that once required multiple people to be performed accurately by one person. The smartphone camera image can also overlay virtual markings or arrows with AR (augmented reality), so when viewing the site through the screen a virtual stake or line is displayed at the target position. As you approach the intended point, markers lock into place, allowing even first-time users to identify installation points accurately without confusion. This intuitive AR guidance function dramatically improves the efficiency of one-person stake-driving and position-setting tasks, even for inexperienced technicians.

• 3D point cloud measurement using LiDAR scanning: By linking LRTK with LiDAR sensors and camera functions on higher-end iPhone and iPad models, wide-area 3D surveying by a single person becomes easy. Walking while scanning the surrounding terrain and structures, LRTK combines the position coordinates it acquires with the smartphone’s LiDAR data to generate high-precision 3D point cloud data where each point is assigned an accurate coordinate. Previously, wide-area terrain surveying required drone photogrammetry or expensive laser scanners, but with LRTK anyone can perform point cloud measurement without special skills. In locations where drones cannot be flown—such as urban areas—workers can simply walk and scan, eliminating restrictions. The acquired point cloud can be checked on the phone on-site and used for overall as-built understanding, volume calculations, and displacement monitoring. As a 3D surveying tool anyone can use, LRTK greatly expands the possibilities for on-site measurement.

• Automatic recording of positioning data and photo linkage: All points acquired with the LRTK app are automatically recorded digitally. Tapping the app’s “Position” button when registering a point instantly saves the three-dimensional coordinates (latitude, longitude, height) with a timestamp and satellite reception status, and point names are automatically numbered and stored in a list. There is no longer any need to copy numbers into a paper field book. Photos taken with the smartphone are automatically tagged with the shooting position coordinates and orientation, so when reviewing later it is immediately clear “where and in which direction a photo was taken.” This prevents human errors such as transcription mistakes or forgetting to link photos with survey points, ensuring that on-site data is accurately and completely recorded.

• Cloud sharing and real-time utilization: Another strength of LRTK is that surveyed data collected on-site can be uploaded and shared to the cloud instantly. With one tap in the dedicated app, you can send recorded coordinate lists and point cloud data to your company’s cloud service, allowing stakeholders to view results before you return to the office. Uploaded data can be immediately viewed on the web-based LRTK Cloud, where stakeholders can inspect plotted coordinates, notes, and attached photos on a map. 3D point cloud data can be displayed in three dimensions in a browser, enabling remote supervisors or clients to grasp on-site details. No dedicated software installation is required—sharing a web link is enough to show the latest survey results—so additional measurement requests or data deficiency notifications can be received in real time. Being able to utilize and review measured data immediately helps prevent rework and accelerates construction decision-making.

• Ease of use through smartphone integration: The convenience unique to the smartphone-attached LRTK cannot be overlooked. Equipment preparation is completed simply by attaching the device to the smartphone, eliminating complicated setup tasks. Even at a first-time site, the time from power-on to satellite acquisition and obtaining an RTK “Fix solution” typically takes only tens of seconds, allowing surveying to begin almost immediately. The dedicated app is designed with a simple, intuitive interface so technicians unfamiliar with the latest surveying devices can master it with minimal practice. Because surveying know-how is standardized and consolidated within the app, anyone can achieve stable accuracy without relying on specific veterans, which is a major advantage. Carried in a pocket as a one-person, one-device tool, it can be taken out and used the moment anyone wants to measure, dramatically improving field mobility. An optional lightweight pole (monopod) allows stable posture for height measurements, and the app lets you easily change the offset value for height correction from ground to device with a single button. This outstanding portability makes LRTK a tool that significantly increases on-site surveying agility.

Comparison with Other Methods and LRTK’s Advantages

As described above, LRTK strongly supports one-person surveying with various advanced functions, and its advantages become clearer when compared with other surveying methods. Compared to traditional labor-intensive surveying, digital surveying with LRTK delivers overwhelming efficiency and accuracy. For example, total station use required setup and line-of-sight maintenance that demanded manpower and time, but LRTK uses satellite positioning, so as long as the sky is not obstructed you can move freely while measuring. Single-person optical distance meters like robotic TS are expensive and require regular adjustments, but LRTK is affordable and easy to maintain. Compared with conventional GNSS surveying equipment, LRTK also offers a far lower initial cost. Procuring dedicated high-precision GNSS receivers and field controllers used to require investments in the millions of yen, but because LRTK leverages smartphones, a high-precision positioning environment can be established for under several hundred thousand yen. Lower cost barriers make it easier for small and medium-sized enterprises and local governments that previously lacked high-precision equipment to adopt the technology.

Moreover, LRTK’s versatility stands out even when compared with other advanced measurement techniques. Drone photogrammetry and ground-based laser scanners can acquire 3D data quickly, but they face flight restrictions, high equipment costs, and require specialist skills. In contrast, LRTK’s person-walking measurement approach is less affected by Radio Law constraints or weather conditions and is easy for anyone to use. For example, in urban areas, indoors, or in forests—where drones are difficult to operate—LRTK can cover the site via walking scans or GNSS positioning. While LRTK can acquire high-precision point clouds comparable to expensive laser scanners, it offers superior mobility and simpler operation. Additionally, LRTK adds precision and functionality that ordinary smartphones alone cannot achieve. In short, the combination of ease × high precision is LRTK’s strength and a unique value that other methods do not provide.

Real-World Examples and Use Cases

What effects has one-person surveying with LRTK produced on sites where it has been introduced? Below are use cases from the construction industry and the public sector.

● Efficiency improvement example at a construction site: At a civil engineering construction site, adopting LRTK for as-built management surveying achieved significant efficiency gains. Tasks that previously required a two-person team and a full day were reportedly completed by one person in just a few hours after LRTK introduction. An approximate 70% or more reduction in work time was achieved, significantly reducing labor costs. The ability to obtain high-density surveying data in real time also enabled comprehensive site measurement, improving overall quality. Analyzing the acquired 3D point cloud data revealed areas that partial sampling methods had missed, aiding early detection of construction errors and preventing rework. LRTK’s introduction represents a good example of enabling accurate surveying by few people in a short period.

● Public sector use case: Local governments have also begun using LRTK as a DX tool for on-site surveying. For instance, in 2023 Fukui City was an early adopter of the LRTK system for surveys at sites affected by heavy rain disaster recovery. Staff could immediately survey discovered damaged areas with their smartphones, reducing round trips between field and office and recording detailed damage conditions in less time than before. As a result, lead times from recovery planning to construction start were shortened, contributing significantly to rapid recovery and cost savings. The relatively low device cost of LRTK was also attractive to municipalities. With simple training, staff could operate the system, allowing municipalities to switch surveying tasks from outsourcing to in-house handling, reducing costs and building internal technical capacity. Thus, one-person surveying with LRTK is proving effective in the public sector, and other municipalities are beginning to consider adoption.

How Work Changes with One-Person Surveying

One-person surveying using LRTK transforms field work processes. The main benefits include:

• labor reduction and lower personnel costs: By reducing required surveying personnel from the traditional two to three people down to one, this helps address labor shortages and substantially cuts personnel expenses. Limited staff can handle multiple sites in parallel, directly improving company-wide productivity.

• Reduced work time: Fast positioning and data processing dramatically shortens the lead time from surveying to drawing creation, quantity calculations, and reporting. Because data measured on-site can be shared to the cloud immediately, as-built verification that used to take days can be completed the same day. Fast checks enable shorter construction schedules and earlier progression to subsequent stages.

• Improved surveying accuracy and data quality: Measuring with RTK-GNSS at centimeter-level accuracy produces high-quality data that meets strict precision requirements. Point cloud measurement enables dense scanning of entire sites, producing detailed survey results without omissions. Smaller errors reduce the need for remeasurement and corrections, enhancing quality control.

• Increased safety: Shorter surveying time reduces workers’ on-site exposure, lowering risks such as heatstroke and accidents. Nighttime work and surveying on busy roads can be completed quickly, avoiding prolonged exposure to hazardous environments. Efficient single-person work also reduces unnecessary gatherings at sites, lowering the risk of contact-related accidents.

• Reduced human error: With automatic digital recording and organization of measurements and photos, mistakes from handwritten notes or data transcription disappear. Missed measurements and omissions can be detected and prevented in real time, enabling production of reliable deliverables. Electronic data management also simplifies inspections and supervision, reducing rework in report preparation.

• Easier skill acquisition and reduced reliance on individuals: Because operations center on an intuitive smartphone app, even inexperienced personnel can learn quickly. With surveying know-how systematized, tasks that previously depended on certain veterans can be performed at a consistent level by anyone. Reduced dependence on individual experience allows organizations to maintain stable surveying quality across the board.

LRTK Survey Procedure and Implementation Flow

Despite its wide range of features, starting to use LRTK is surprisingly simple. The basic flow is as follows.

• Equipment and app preparation: First, obtain the LRTK device and attach the dedicated mounting case or adapter to the iPhone or iPad you will use. Next, download and install the official “LRTK” app, which is available free from the App Store. Pair your smartphone with the LRTK device (Bluetooth connection, etc.) in advance.

• On-site setup: When you arrive at the site, firmly attach the LRTK device to your phone and power it on. Launch the LRTK app and connect to the device; GNSS reception will start automatically. Wait tens of seconds; once the app shows an RTK “FIX solution” and the position stabilizes, you are ready to survey. There is no need to set up a heavy tripod, and startup procedures require very little time.

• Positioning and measurement execution: Move to the point you want to measure and tap the app’s “Position” button to record high-precision coordinates for that location. You no longer need an assistant to hold a prism. If you want to measure a wide area continuously, simply walk while holding the phone and automatic point cloud scanning will occur, generating a real-time 3D model of the surroundings. For stake-driving and position-setting tasks, use the coordinate navigation feature and follow the on-screen prompts to identify target positions accurately by yourself.

• Result confirmation and recording: Measured coordinate data and generated point cloud models are immediately visualized within the app, and distance and angle calculations can be performed on-site. If you take photos, they are automatically saved as high-precision record photos with positioning information. Recorded data is managed in a list in the app, and editing point names or adding notes is easy. Without a paper field book, all measurement results can be checked and managed on the phone, making on-site checks smooth.

• Data sharing and utilization: After surveying, upload measurement data to the cloud with one tap in the app. By the time you return to the office, stakeholders have already received the results and can view and confirm the data over the internet. If supervisors or clients in remote locations request additional measurements or data corrections, you can receive feedback on-site and immediately conduct additional measurements if needed. Proceeding while sharing information in real time minimizes subsequent “remeasuring” or reworking at the site.

As described above, using LRTK allows field surveys that previously required multiple people to be completed with remarkably simple procedures. Because it is so easy to use, even those attempting one-person surveying for the first time can feel secure. One-person surveying using smartphones and GNSS not only dramatically streamlines surveying operations but also, through rapid data sharing, greatly improves the accuracy of downstream construction management and decision-making.

Conclusion

One-person surveying, a new solution for the labor-shortage era, is becoming an industry-wide trend. Among such solutions, LRTK has established a new standard for accurate and efficient one-person surveying by fusing smartphones and GNSS into an innovative technology. LRTK’s high accuracy and ease of use make it a trump card for on-site DX that aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative. Companies and local governments that have introduced it are already seeing clear results in productivity improvement and cost reduction.

If your company aims to be No.1 in the industry, actively adopting the latest technologies is essential. Introducing one-person surveying with LRTK lets you evolve field operations at unprecedented speed and precision. Why not experience this next-generation surveying method that can be started with just a smartphone? LRTK will be a powerful partner to expand your on-site capabilities and lead your company to the top of the industry.