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, the construction and civil engineering industries have increasingly focused on “one-person surveying” — surveying work carried out by a single person. With labor shortages and work-style reforms demanding attention, the need to complete surveying tasks that traditionally required two or more people with just one person has grown. In Japan in particular, experienced surveyors are aging while younger talent is dwindling, forcing firms to efficiently cover many sites with limited staff. Against this backdrop, efforts to reduce labor through the use of cutting-edge technologies have accelerated, and “surveying that can be done by one person” is expected to play a central role across the industry.

Conventional surveying work has typically relied on multi-person teams, consuming significant time and manpower. However, advances in digital technology have lowered the barriers to solo work that were previously difficult. The government is also promoting the use of ICT to boost productivity in construction (e.g., the Ministry of Land, Infrastructure, Transport and Tourism’s *i-Construction* initiative), and digital transformation (DX) is becoming a requirement in the surveying field as well. Adapting to these industry changes and aiming to be the industry No.1, companies cannot ignore the challenge of accommodating one-person surveying.

Basics and Challenges of One-Person Surveying

“One-person surveying” refers to completing site surveying workflows alone using surveying instruments such as total stations and GNSS positioning devices. For example, total station surveys that normally require two people can be done solo using automatic-tracking instruments (robotic total stations), where a single operator guides the reflector prism to the target point and measures remotely. High-precision GNSS receivers combined with mobile devices have also enabled real-time positioning through communication with reference stations—so-called RTK surveying—which has become a popular method for solo surveys.

However, traditional one-person surveying has had several challenges. First, the equipment used has often been expensive and difficult to handle. Automatic-tracking total stations and professional-grade RTK-GNSS receivers require investments of several million yen per unit, and each device needs specialized setup and operational skills. Transporting and setting up heavy equipment alone is also burdensome, and installing such devices in confined spaces or on uneven terrain can be difficult. Second, conventional methods often involved time-consuming recording and data-sharing processes, meaning that even if surveying could be done by one person, immediacy and efficiency were not fully realized. Fieldworkers frequently had to handwrite numbers in field notebooks or later match photos with drawings, consuming much administrative time. Furthermore, solo work often reduces the opportunities for checking survey results, raising concerns about human error such as missed measurements or record-keeping mistakes.

To overcome these issues and achieve truly practical one-person surveying, a new system was needed: one that anyone could use easily while delivering high-precision surveying. The next-generation surveying system developed as this new standard is LRTK, which combines smartphones and GNSS technology.

What Is LRTK? Its Features and Development Background

LRTK (pronounced “L-R-T-K”) is a surveying solution centered on a compact positioning device developed by Reflexia Inc., a startup spun out of Tokyo Institute of Technology. At its core is the ultra-compact RTK-GNSS receiver “LRTK Phone,” which attaches to a smartphone and delivers an all-in-one workflow from on-site positioning to data recording and sharing. The device itself fits in a pocket, weighing only about 150 g and measuring roughly 1 cm thick, yet it houses a high-performance antenna and battery sufficient for high-precision outdoor positioning.

By attaching the LRTK device to your smartphone (iPhone or iPad) using a dedicated case or mount and connecting via Bluetooth or Lightning, your everyday smartphone instantly becomes a centimeter-level surveying instrument. Tasks that previously required tripod-mounted equipment or expensive dedicated controllers for RTK surveys can now be handled with a simple smartphone plus a compact device. The system supports network RTK via the Ntrip method using the Geospatial Information Authority of Japan’s reference station network, and it also accepts free correction signals (CLAS) provided by Japan’s quasi-zenith satellite “Michibiki,” enabling real-time high-precision positioning anywhere in Japan. Even in mountainous areas without cellular coverage, as long as the sky is visible it can receive correction data directly from satellites, so it is not limited by site location.

The system was developed out of a desire to make surveying more accessible and labor-saving. According to Mr. Takayasu Motohiro, CEO of Reflexia (a specially appointed assistant professor at Tokyo Institute of Technology), LRTK was designed with the goal of a “one-person-one-device” field tool—something anyone can carry in a pocket and quickly use to perform high-precision surveying when needed. LRTK was born as an innovative tool to promote on-site DX (digital transformation).

How LRTK Creates a New Standard for One-Person Surveying

LRTK’s unique approach of fusing smartphones with GNSS realizes a form of solo surveying that was previously unattainable. Its advanced features are becoming the new benchmark for one-person surveying. Key characteristics include:

• Centimeter-level GNSS positioning accuracy: LRTK’s most notable feature is its high-precision RTK-GNSS positioning, which reduces satellite positioning errors to within a few centimeters. While typical smartphone GPS has errors of around 5–10 m, using the LRTK device and real-time kinematic (RTK) techniques corrects those error sources to pinpoint positions with centimeter accuracy. This enables one person to perform tasks that require millimeter-to-centimeter precision, such as boundary point measurements and as-built checks. It provides reliability and measurement quality that far exceed tape measures or standalone GPS devices.

• Stake-driving support via AR navigation: The LRTK smartphone app includes a coordinate navigation function to support staking and layout work. For preset target coordinates, it displays in real time how far and in which direction you need to move—for example, “move east by ○ cm” or “move north by ○ cm.” The operator simply adjusts position by a few centimeters according to the smartphone display, allowing staking operations that once required multiple people to be handled solo with accuracy. The app can overlay virtual markings or arrows on the camera view using AR (augmented reality), showing a virtual stake or line on the screen as you approach the target. Markers lock into place as you get closer, making it easy to identify the exact installation point even on an unfamiliar site. This intuitive AR guidance function dramatically improves efficiency for solo staking and layout tasks, even for less-experienced technicians.

• 3D point cloud measurement using LiDAR scanning: By combining LRTK with LiDAR sensors and camera functions on high-end iPhone and iPad models, wide-area 3D surveying by a single person becomes simple. Walking around while scanning lets the LRTK-provided position coordinates be fused with the smartphone’s LiDAR data to produce high-precision 3D point cloud data with accurate coordinates for each point. Where wide-area terrain surveys once required drones or expensive laser scanners, LRTK allows easy point cloud acquisition without specialized skills. It is useful in locations where drones cannot fly—urban areas, for example—since a worker can simply walk and scan. The captured point cloud can be checked on the smartphone on-site and used for as-built overviews, earthwork volume calculations, displacement monitoring, and more. As a solution for 3D surveying anyone can perform, LRTK greatly expands on-site measurement possibilities.

• Automatic recording of positioning data and photo linkage: All measured points captured by the LRTK app are automatically recorded digitally. Tapping the app’s “Position” button when registering points instantly saves that time-stamped latitude, longitude, and altitude (3D coordinates) along with satellite reception status, and point names are auto-numbered and accumulated in a list. There’s no need to transcribe numbers into a paper field book. Photos taken with the phone’s camera are automatically tagged with capture coordinates and orientation, making it immediately clear where and which direction each photo was taken. This prevents human errors like transposition mistakes or forgetting to link photos to points, ensuring comprehensive and accurate recording of field data.

• Cloud sharing and real-time utilization: A major strength of LRTK is the ability to upload and share survey data to the cloud on the spot. With a single tap in the dedicated app, recorded coordinate lists and point cloud data can be sent to your company’s cloud service, allowing stakeholders to review results before you return to the office. Uploaded data can be instantly viewed on the web-based LRTK Cloud, where plotted points, coordinate values, notes, and attached photos are accessible to relevant parties. 3D point clouds can also be rendered in a browser, enabling remote supervisors or clients to grasp site details. No specialized software installation is required—sharing a web link allows others to view the latest survey results, facilitating real-time feedback on additional measurements or data corrections. Immediate utilization of measured data minimizes rework and speeds construction decision-making.

• Ease of use through smartphone integration: The convenience unique to a smartphone-mounted system is not to be overlooked. Preparing equipment is as simple as attaching the device to your smartphone—no complex setup is required. On a first use, the time from power-on to obtaining an RTK “Fix” typically takes only tens of seconds, allowing you to start surveying almost immediately. The dedicated app’s interface emphasizes simplicity and intuitive operation, enabling technicians unfamiliar with advanced surveying equipment to become proficient after brief practice. Surveying know-how is standardized and embedded within the app, so anyone can achieve stable accuracy without relying on specific veterans. With one device per person carried in a pocket, you can take it out and measure the moment the need arises, significantly improving field agility. An optional lightweight pole (monopod) provides stable posture for height-sensitive measurements, and the app allows quick adjustment of offset values (height correction from ground to device) with a single button. This outstanding portability and handling make LRTK a tool that greatly enhances on-site surveying mobility.

Comparison with Other Methods and LRTK’s Advantages

As described above, LRTK strongly supports solo surveying through a variety of advanced features, and its advantages become clearer when compared with other surveying methods. Compared with traditional manual surveying, digital surveying with LRTK delivers overwhelming efficiency and accuracy. For example, total station use previously required manpower and time to set up equipment and secure lines of sight, but because LRTK uses satellite positioning, you can move freely and measure as long as the sky is not obstructed. Robotic total stations and similar one-person optical distance meters are expensive and require periodic calibration, whereas LRTK can be maintained affordably. Compared with conventional GNSS surveying equipment, LRTK’s initial introduction cost is dramatically lower. Equipping a site with dedicated high-precision GNSS receivers and field controllers once required investments on the order of millions of yen, but LRTK leverages smartphones so you can establish a high-precision positioning environment for well under several hundred thousand yen. Lower cost barriers make adoption easier for small-to-medium enterprises and local governments that previously could not afford high-precision gear.

Moreover, LRTK’s versatility stands out even when compared with other advanced measurement methods. Drone photogrammetry and terrestrial laser scanners can obtain 3D data quickly, but they face restrictions such as flight regulations, equipment costs, and the need for specialized skills. LRTK’s human-walking measurement approach avoids many regulatory and weather-related limitations and offers the advantage of being usable by anyone. For example, in urban areas, indoors, or forests where drone flights are difficult, LRTK can cover sites via walking scans and GNSS positioning. It can produce high-precision point clouds comparable to expensive laser scanners while offering superior mobility and simpler handling. LRTK adds capabilities that ordinary smartphones alone cannot achieve, delivering both ease-of-use × high precision, which is its unique value proposition unmatched by other methods.

Real-World Examples and Use Cases

What effects does LRTK bring to sites where it has been introduced? Here are examples from the construction industry and public sector use cases.

● Efficiency gains at construction sites: At a civil engineering construction site, introducing LRTK for as-built control measurement dramatically improved efficiency. Where as-built measurement once required two people and a full day, post-LRTK implementation a single person could finish the job in a few hours. Reported work time reductions of over 70% significantly reduced labor costs. The ability to capture high-density, real-time survey data also allowed comprehensive site measurement, improving quality. Analysis of the resulting 3D point cloud revealed areas that would have been overlooked by conventional spot measurements, aiding early detection of construction mistakes and preventing rework. LRTK’s introduction is a prime example of achieving high-precision surveying with fewer people in less time.

● Public-sector use cases: Local governments have also begun using LRTK as a DX tool for field surveys. For example, Fukui City quickly adopted the LRTK system in 2023 for surveys at sites affected by heavy rain disasters. Staff could immediately measure damages with the smartphone in hand, reducing repeated trips between field and office while recording detailed damage information faster than before. This shortened lead times from recovery planning to construction start, contributing significantly to rapid restoration and cost savings. The relatively low device cost was attractive to municipalities as well. After simple training, municipal staff could operate LRTK, enabling a shift from outsourced surveying to in-house handling—reducing costs and building internal capabilities. Thus, one-person surveying with LRTK is proving effective in the public sector, and other municipalities are beginning to consider adoption.

How Work Will Change with One-Person Surveying

One-person surveying using LRTK transforms on-site workflows. Key benefits include:

• Labor reduction and lower personnel costs: Required survey personnel can be reduced from two to three people down to one, helping alleviate labor shortages and significantly cutting labor costs. Limited staff can cover multiple sites concurrently, directly improving company-wide productivity.

• Shorter working time: Fast positioning and data processing drastically reduce lead times from surveying to drawing creation, quantity calculation, and reporting. Because field data can be immediately shared to the cloud for review, as-built confirmations that used to take days can often be completed the same day. Rapid checks enable schedule shortening and earlier progress to subsequent construction phases.

• Improved measurement accuracy and data quality: RTK-GNSS yields centimeter-level accuracy, ensuring high-quality data that meets strict precision requirements. Point cloud measurement offers dense scanning of entire sites, producing comprehensive survey results without omissions. With smaller errors, re-measurements and corrections decrease, improving quality control.

• Enhanced safety: Shorter survey times reduce workers’ time on site, lowering risks such as heatstroke and accidents. Night work or surveying on busy roads can be completed more quickly, reducing exposure to hazardous conditions. Efficient solo work also reduces unnecessary gatherings of personnel, cutting the risk of contact-related incidents.

• Reduced human error: Automatic digital recording and organization of measurements and photos eliminate handwriting mistakes and data transcription errors. Real-time tracking prevents missed measurements and omissions, enabling reliable deliverables. Electronic data management simplifies inspections and supervision and reduces rework during report preparation.

• Easier skill acquisition and reduced dependence on individuals: Because the system centers on an intuitive smartphone app, even inexperienced staff can learn quickly. With surveying know-how systematized, tasks that previously relied on particular veterans can be performed by anyone to a consistent standard. This reduces dependence on individual experience and helps maintain stable surveying quality across the organization.

LRTK Survey Procedure and Implementation Process

Despite its diverse features, getting started with LRTK is surprisingly simple. The basic flow is as follows:

• Prepare equipment and app: Acquire the LRTK device and mount it to your iPhone or iPad using the dedicated case or adapter. Download and install the official “LRTK” app (available for free from the App Store). Pair the smartphone and LRTK device (e.g., via Bluetooth) in advance.

• On-site setup: Upon arriving at the site, securely 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. After waiting tens of seconds until the app displays an RTK “FIX” and the position stabilizes, you are ready to survey. No heavy tripod is required, and startup takes very little time.

• Positioning and measurement: Move to the point you want to measure and tap the app’s “Position” button to record the high-precision coordinates for that spot. There’s no need for an assistant to hold a prism. To continuously measure a wide area, simply walk while holding the phone—automatic point cloud scanning will occur and a real-time 3D model of the surroundings is generated. For staking and layout, follow the coordinate navigation prompts on the screen to identify target positions accurately on your own.

• Reviewing and recording results: Measured coordinate data and generated point cloud models are immediately visualized in the app, and distance and angle calculations can be performed on-site. If you take site photos, they are saved automatically with high-precision positioning metadata. Recorded data is managed in an in-app list, and editing point names or adding notes is simple. Without a paper field book, you can review and manage all measurement results on the smartphone, making on-site checks smooth.

• Data sharing and utilization: After completing the survey, upload the data to the cloud with one tap in the app. By the time you return to the office, results have already been shared with stakeholders, who can immediately view and review the data online. If a supervisor or client remotely requests additional measurements or data corrections, you can receive that feedback on the spot and perform supplementary measurements as needed. Real-time information sharing minimizes later re-measurements and site rework.

As shown, LRTK enables field surveys that formerly required several people to be completed through surprisingly simple procedures. Its ease of use is such that even teams attempting one-person surveying for the first time can do so with confidence. Smartphone and GNSS-driven “one-person surveying” not only dramatically improves surveying efficiency but, through faster data sharing, also greatly enhances the accuracy of subsequent construction management and decision-making.

Conclusion

One-person surveying is becoming a new solution in an era of labor shortages and is emerging as an industry-wide trend. Among the options, LRTK has established a new standard for solo, accurate, and efficient surveying by fusing smartphones with GNSS. LRTK’s combination of high precision and ease of use aligns well with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative and serves as a powerful on-site DX tool. Companies and municipalities that have implemented LRTK are already seeing clear results in productivity gains and cost reductions.

If your company aims to be industry No.1, proactively adopting the latest technologies is essential. By introducing LRTK for one-person surveying, you can evolve on-site operations with unprecedented speed and precision. Why not experience this next-generation surveying method you can start with a single smartphone? LRTK is poised to expand your site’s capabilities and become a powerful partner in guiding your company to the top of the industry.