LRTK Revolutionizing One-Person Surveying | Changing the Norms of Solo Work!

Recently, the surveying industry has been focusing on the keyword "one-person surveying". Driven by labor shortages and work-style reforms, the conventional idea that "surveying must be done by a team" is being reconsidered, and a new surveying style that can be completed by a single technician is in demand. This article explains the background behind the attention on one-person surveying and the traditional challenges, the mechanism of solo surveying enabled by new technologies, and the features and benefits of the cutting-edge tool LRTK at the center of this shift. Learn about the revolutionary surveying method driven by LRTK that changes the norms of solo work and see how it can improve efficiency on site.

Background Behind the Attention on One-Person Surveying and Traditional Challenges

Surveying performed at construction and civil engineering sites is an essential process for quality control and as-built verification. However, it has traditionally been carried out by multiple-person teams. For example, in surveys using a total station, one person operates the instrument while another stands at the target point holding a prism at a distant location. Such labor-dependent surveying has become a major burden amid worsening labor shortages and an aging workforce. The traditional methods have also faced the following issues.

• Personnel cost and availability: Because a 2–3 person team is the norm, surveys can be delayed on sites with insufficient staff. There is also the cost of securing a skilled surveyor and an assistant.

• Time and labor burden：On large sites with hundreds of points to measure, even multiple people can take a full day or more. Post-survey data processing and drawing creation at the office are also required, extending overall lead times.

• Risk of human error：Handwritten notes can lead to transcription mistakes in point names or values, and photos may not be properly linked to points. Errors unnoticed on site can require remeasurement later.

• Skill dependency：Operation of advanced surveying equipment and experience tend to be concentrated in veterans; if a specific person is absent, surveying work may stall. Standardizing skills across the site has been a challenge.

Against this backdrop, demand has grown for the ability to “complete surveying efficiently by a single person,” and attention to one-person surveying has rapidly increased.

Technological Innovations That Enable Solo Surveying

To complete a survey by one person, the power of the latest technologies is indispensable. Fortunately, surveying technology has advanced dramatically in recent years, and various solutions supporting one-person surveying have emerged. Representative examples are the use of robotic total stations and GNSS (GPS) positioning.

• Robotic total stations: A total station with automatic tracking can follow a prism automatically, allowing one operator to measure distances and angles without an assistant. However, line-of-sight is required, the equipment is expensive, and skilled handling is necessary.

• RTK-GNSS positioning: Advances in satellite positioning have also supported one-person surveying. In particular, RTK (Real-Time Kinematic) GNSS combines corrections from a base station and a rover to achieve centimeter-level positioning in real time. Because it provides high-precision positioning over wide areas without line-of-sight constraints, it is well suited for a single person to perform staking and as-built measurements. National and industry initiatives such as i-Construction and DX (digital transformation) are promoting ICT adoption, and RTK-GNSS–based solo surveying is becoming the new norm on many sites.

More recently, solutions that combine smartphones with these high-precision positioning technologies have made one-person surveying even more accessible. The idea is to turn the smartphone everyone carries into a high-precision surveying instrument. Leading the way is LRTK, a compact device developed by Refixia Inc., a startup from Tokyo Institute of Technology.

What is LRTK? One-Person Surveying Achieved with a Smartphone

LRTK is an ultra-compact RTK-GNSS receiver designed to be attached to a smartphone. Weighing only about 160 g, with a housing about 1 cm (0.4 in) thick that contains the antenna and battery, it connects to a smartphone via Bluetooth or a Lightning connector. By launching the compatible app and acquiring satellites, the palm-sized device and a smartphone alone can provide centimeter-level positioning (half-inch accuracy). Tasks that previously required tripod-mounted instruments can now be completed with a pocketable device + smartphone.

Attach LRTK to your smartphone and it instantly becomes a "smartphone surveying instrument" anyone can carry. For example, with an iPhone and LRTK, a single person can handle on-site staking, as-built management, and even 3D terrain scanning. Without expensive specialized equipment or multiple personnel, you can quickly take it out and survey anywhere, anytime—an enormous advantage in mobility. It is attracting attention as a groundbreaking tool that revolutionizes one-person surveying.

Now, let’s look at the specific functions and features LRTK offers.

Main Functions and Features of LRTK

• Centimeter-level high-precision positioning (half-inch accuracy): LRTK’s main feature is that GNSS enables precise positioning with errors of a few centimeters (a few inches). While typical smartphone GPS has errors of about 5-10 m (16.4-32.8 ft), LRTK uses RTK corrections in real time to achieve the accuracy needed for tasks such as setting boundary stakes and as-built verification. Because absolute coordinates can be obtained with high precision, boundary surveying and detailed as-built measurements that were previously difficult for a single person are now possible.

• AR-guided stake placement coordinate navigation: The LRTK smartphone app includes a navigation function that guides the user to pre-set target coordinates. By following on-screen, real-time prompts such as "5 cm east (2.0 in)" or "10 cm north (3.9 in)," the user can move the smartphone to precisely identify the stake point. Virtual markers can also be overlaid on the camera view via AR, so even those new to a site can accurately determine stake positions without hesitation. Positioning tasks that once required multiple people can be handled smoothly by one person.

• 3D point-cloud surveying via LiDAR scanning: LRTK can integrate with iPhone LiDAR sensors and cameras to convert site terrain and structures into 3D point-cloud data on the spot. Simply walk around holding the smartphone to scan the surroundings, and you obtain a point-cloud model with high-precision coordinates assigned to each point. Because even details that were previously overlooked are captured, it can be used for comprehensive as-built understanding, volume calculations, and displacement monitoring. Wide-area 3D surveying can be performed by anyone with just a smartphone, without expensive laser scanners or drones.

• One-tap positioning and automatic recording: At the desired point, a single tap on the smartphone screen records the latitude, longitude, and elevation at that moment. The LRTK app automatically saves the timestamp and positioning status in the background, and point names are auto-numbered for list management. There is no need to copy into paper field books; if you take photos, image files are tagged with location coordinates and orientation, making it clear later which point a photo was taken at. This reduces tedious note-taking and organization, and prevents recording omissions and mistakes.

• Real-time use via cloud sharing: Survey data collected on site can be uploaded to the cloud and shared with stakeholders in real time. With a tap of the app’s share button, recorded coordinate lists and point-cloud data are synced to the LRTK cloud. Supervisors and colleagues can check results in a PC browser before the surveyor returns to the office, viewing plotted points, photos, and notes on a map instantly. Data can be shared with clients via a URL without special software, allowing checks and additional instructions to be received on the spot. Because measured data can be used immediately in the next steps, it prevents rework and speeds decision-making across the project.

• Ease of use unique to smartphone-mounted devices: Since LRTK attaches to a smartphone, it is far easier to carry and set up than conventional instruments. Even on a first-time site, preparations from satellite acquisition to obtaining an RTK "FIX solution" can be completed in a few tens of seconds. The dedicated app features an intuitive interface, allowing users with little surveying experience to become proficient in a short period. Surveying know-how is built into the app and standardized, so anyone can achieve stable accuracy. Because site workers can carry one in their pocket, LRTK offers exceptional agility: you can immediately take it out and measure whenever you need to.

Benefits of Introducing LRTK

By introducing LRTK with the functions described above, the following benefits can be realized at survey sites.

• Labor reduction and lower personnel costs: Surveys that previously required 2–3 people can be conducted by one person, enabling significant staffing reductions. Limited personnel can cover multiple sites, directly reducing labor costs and alleviating labor shortages.

• Dramatic reduction in work time: High-precision positioning and automatic data processing drastically shorten the time from surveying to drawing creation, quantity calculation, and reporting. For example, as-built measurements that used to take two people a full day have been completed by one person in a few hours after LRTK adoption. Time reductions of over 70% have been achieved in some cases, dramatically improving work efficiency.

• Improved surveying accuracy and data quality: Precise measurements via RTK-GNSS yield low-error data that helps ensure quality. Dense point-cloud measurements allow comprehensive site coverage with no omissions, producing reliable deliverables. Higher accuracy reduces remeasurement and rework, allowing smoother project progress.

• Enhanced safety: Shorter surveying time reduces the time workers spend on site, lowering risks such as heatstroke in hot environments and accidents in high places or high-traffic areas. Completing tasks quickly by one person minimizes exposure to hazardous conditions.

• Prevention of human error: Measurement values and photos are digitally recorded automatically, eliminating handwriting mistakes and data transcription errors. Centralized cloud management removes concerns about missing records. Work can be based on always-accurate data, yielding highly reliable results.

• Ease of learning and elimination of skill dependency: With a smartphone-app–centered, simple operation system, anyone can use LRTK after a short training period. With surveying know-how systematized, tasks that "only a certain person can do" are reduced, and acceptable accuracy can be maintained even in the absence of veterans. Organizations can standardize surveying skills and facilitate skill transfer within teams.

Effects of LRTK Seen in Case Studies

Let’s look at actual examples of LRTK deployment to confirm its effects.

Construction site example: At a certain civil engineering construction site, the introduction of LRTK significantly improved surveying efficiency. As-built measurements that previously took two people a full day were completed by one person in a few hours after adopting LRTK—about a 70% or greater time reduction—resulting in labor cost savings and higher-quality, high-density measurements across the site. The acquired 3D point-cloud data revealed areas that had been missed by sample checks, helping early detection of construction mistakes and preventing rework.

Municipal example: Local governments have also begun using LRTK as part of on-site DX efforts. For example, Fukui City was an early adopter of the LRTK system in 2023 for disaster recovery site surveys. Because staff can immediately start surveying with a smartphone upon discovering damaged areas, there is no need for repeated trips between the site and the office, allowing faster and more detailed damage recording than before. As a result, lead times from planning recovery to starting construction have been shortened, contributing significantly to early recovery and cost savings. Because LRTK’s initial introduction cost is relatively low, it is easy for municipalities to adopt, enabling them to perform surveying in-house rather than outsourcing, which reduces costs and internalizes skills. In this way, one-person surveying with LRTK has produced results in the public sector, and other municipalities are now considering adoption.

How to Start One-Person Surveying with LRTK

LRTK offers many advantages, and its introduction and use are very simple. Finally, let’s confirm the basic steps to start one-person surveying with LRTK.

• Prepare the device and app: First, obtain the LRTK device and attach it to a compatible smartphone (for example, an iPhone). Install the dedicated "LRTK" app on the smartphone (available for free download from the App Store or Google Play).

• Set up on site: Upon arrival at the survey site, turn on the power of the LRTK attached to the smartphone and launch the app. Once the device and smartphone are connected, GNSS satellite reception begins. Wait a few tens of seconds, and when the RTK "FIX solution" (a high-precision reception state) is obtained, you are ready to go.

• Measurement and data acquisition: Move to the point you want to measure and simply tap the "Position" button on the smartphone screen to automatically record the high-precision coordinates of that point. If you want to measure a wide area continuously, just walk around holding the smartphone to perform the point-cloud scan mentioned above. For stake placement, follow the on-screen guidance to identify the target point accurately by yourself.

• Share and use results: You can check acquired point data and point-cloud models on the smartphone and attach on-site photos as needed. After surveying, upload the data to the cloud with one tap from the app. You can share the results with stakeholders before returning to the office and receive additional instructions or confirmations on the spot. This allows you to proceed smoothly to the next process without rework.

With these steps, surveying work that previously required multiple people can be smoothly completed by one person. LRTK is a powerful partner that changes the norms of “solo work.” By using this highly precise and easy-to-use tool, the conventional belief that “surveying must be done by a team” will become a thing of the past. For sites struggling with labor shortages and productivity improvements, now is an excellent time to adopt one-person surveying with LRTK. Why not bring innovation to your site with cutting-edge technology and update the norms of surveying together?