What Can LRTK Do to Enable One-Person Surveying? [Features, Price, and Case Studies]

Overview and Importance of One-Person Surveying

In recent years, one-person surveying has attracted significant attention on construction and civil engineering sites. Amid labor shortages and workstyle reforms, there is a growing demand to complete surveying tasks that formerly required two or more people with just one person. In Japan in particular, experienced surveyors are aging while the number of young engineers is declining, creating pressure to cover many sites efficiently with limited personnel. Into this environment has come a solution that leverages smartphones and modern technologies to enable one person to perform accurate surveys.

Traditional surveying required multi-person teams to operate heavy equipment and involved labor-intensive processes. Today, by combining AR (augmented reality) technology with high-precision GNSS positioning (satellite positioning), the smartphone everyone carries is increasingly transforming into a high-precision surveying instrument. A representative example is LRTK, a compact RTK-GNSS device developed by Reflexia Inc., a startup originating from Tokyo Institute of Technology. Simply attaching it to an iPhone or other smartphone enables centimeter-level positioning (cm level accuracy (half-inch accuracy)), bringing an era in which layout marking, as-built management, and even 3D measurement can be handled solo.

This article explains in detail the importance of one-person surveying and the challenges of traditional methods, the features and pricing of the new LRTK technology, real-world use cases, and the benefits and steps to get started.

Challenges of Traditional Surveying and Why Solo Work Is Needed

First, let’s organize the challenges of conventional surveying. Surveying on construction and civil engineering sites is an essential process for quality control and as-built verification, but it has traditionally been carried out by multi-person teams. A skilled surveyor and an assistant typically work as a pair, and in some cases a recorder joins to form a three-person team. For example, with total station (TS) surveying, one person operates the instrument while another carries a prism and stands at the distant measurement point. Such manpower- and labor-intensive surveying places a heavy burden on sites already suffering from chronic staff shortages.

Moreover, traditional surveying tends to consume large amounts of time and effort. When measurement points number in the hundreds across a wide site, it’s not uncommon for teams to spend an entire day moving around the site to complete measurements. Even after fieldwork, much office work remains—plotting measured points onto drawings, calculating quantities, and preparing reports—so data captured on site often cannot be used immediately for construction. This inefficiency can delay recognition of measurement errors or omissions, requiring rework.

Additionally, human error and knowledge centralization cannot be ignored. Mistakes such as copying measured values incorrectly from handwritten notes or failing to tag photos with location information are common. Because advanced surveying equipment requires specialized skills, teams often depend on certain veterans; when such individuals are absent, work can halt while waiting for surveying. Given these issues—staff shortages, inefficient workflows, and the risk of errors—expectations for one-person surveying have risen year by year as a means of transforming conventional practices.

How LRTK Works and Key Features That Enable One-Person Surveying

LRTK is an innovative surveying system that combines a smartphone with a compact GNSS receiver. It is an ultra-compact RTK-GNSS terminal designed to attach to the back of an iPhone; it weighs about 165 g and has a housing roughly 1 cm (0.4 in) thick that contains a high-performance antenna and a battery. By securing it to a smartphone with a dedicated case or magnet and connecting via Bluetooth or Lightning, an ordinary smartphone instantly becomes a high-precision GNSS surveying instrument. Surveying that used to require setting up a tripod and installing equipment weighing several kilograms can now be completed solo on site with a device that fits in a pocket plus a smartphone. It is attracting attention as a solution that opens the age of “smartphone surveying.”

The LRTK device supports advanced RTK positioning and, within Japan, can utilize the Geospatial Information Authority of Japan’s electronic reference station network for network RTK (Ntrip method) or the free augmentation signal (CLAS) provided by the Quasi-Zenith Satellite “Michibiki” to correct positioning errors in real time to within a few centimeters (cm level accuracy (half-inch accuracy)) almost anywhere in the country. Even in mountainous areas or disaster sites without cellular coverage, if the sky above is open the device can receive correction data directly from satellites for high-precision positioning. Despite its simple design—powered and controlled from the smartphone—it also includes a battery capable of supporting several hours of continuous measurement, so anyone can bring an iPhone plus LRTK to a site and immediately start centimeter-level surveying (cm level accuracy (half-inch accuracy)).

Now let’s look at the specific functions of LRTK that support one-person surveying.

Centimeter-level Positioning via High-Precision GNSS (RTK)

LRTK’s greatest feature is its GNSS-based centimeter-level positioning (cm level accuracy (half-inch accuracy)). Typical GPS built into smartphones has errors around 5–10 m, but LRTK uses the RTK (real-time kinematic) method to correct errors down to a few centimeters. By analyzing signals from multiple satellites and comparing data with reference stations to remove error factors, it instantaneously computes highly accurate absolute coordinates. This makes it possible for one person to handle tasks that require high precision, such as boundary surveying and as-built verification. It is far more accurate than tape measures or standalone GPS and can reliably meet precision requirements needed for quality assurance.

Stakeout Support via AR Navigation

The LRTK smartphone app includes a coordinate guidance (navigation) function. For pre-set target point coordinates, it displays in real time the direction and distance you need to move from your current position, such as “move 5 cm east” or “10 cm north.” By simply following the on-screen instructions while holding the smartphone and making small adjustments, stakeout work that used to require multiple people can be accurately completed by one person. The app can also overlay AR displays on the smartphone camera feed so that virtual stake markers or arrows appear on the screen at the target locations. As you approach the target, the marker locks into place at the designated spot, enabling even first-time users at a site to find the installation location accurately without getting lost. This AR navigation intuitively guides users to target coordinates, supporting solo stakeout and layout tasks even for those with limited surveying experience.

Point Cloud Measurement via LiDAR Scanning

With LRTK, a single person can easily capture three-dimensional point cloud data. By integrating with the iPhone’s LiDAR sensor and camera functions to scan surrounding terrain and structures, LRTK attaches high-precision position coordinates to each scanned point to generate detailed 3D point clouds. Walking around the site while scanning can cover wide areas and document spots that would have been overlooked with traditional methods. The acquired point clouds can be used for as-built overview, volume calculations, and displacement monitoring. Whereas specialized laser scanners or drone surveys required expensive equipment and complex alignment workflows, LRTK enables anyone to perform fast point cloud measurements with just a smartphone.

Automatic Recording of Positioning Data and Photo Tagging

All survey results obtained by the LRTK app are automatically recorded digitally. With a tap of the positioning button, the current latitude, longitude, and elevation are saved along with a timestamp and satellite tracking status, and point names are automatically numbered and stored in a list. There is no need to transcribe numbers into a paper field book. Photos taken with the smartphone camera are automatically tagged with position and orientation, so it is immediately clear later which point and direction each photo corresponds to. This prevents human errors such as mistyped measurements or forgetting to associate photos with points, ensuring that data captured on site is recorded completely and accurately.

Cloud Sharing and Real-Time Use

Another strength of LRTK is the ability to quickly share survey data to the cloud from the field. With a single tap in the app you can upload recorded coordinate lists and point cloud data to the cloud and share results with stakeholders before returning to the office. Uploaded data can be reviewed immediately in the LRTK cloud service on the web. Measured points are plotted on maps, and each point’s coordinates, notes, and photos can be viewed. 3D point clouds are displayed in a browser-based viewer so details can be understood without being on site. Since no dedicated software is required and sharing a URL is sufficient, clients and remote teams can access information easily, enabling real-time review and additional requests. Being able to use measured data immediately helps prevent rework and speeds up decision-making.

Ease of Use Unique to a Smartphone-Mounted System

Compared with traditional surveying instruments, LRTK is overwhelmingly easier to handle. Equipment preparation is completed simply by attaching the device to a smartphone, eliminating troublesome setup. Even at a first-time site, it takes only a few dozen seconds to capture satellites and obtain an RTK “FIX solution” (high-precision solution). The dedicated app has a simple and intuitive interface, so technicians with limited experience operating specialized instruments can learn quickly. Surveying know-how is centralized and standardized in the app, enabling anyone to perform stable surveys. Because each person can carry a unit in their pocket, measurements can be taken whenever needed, greatly improving field mobility. Using an optional lightweight pole (monopod) also makes it easy to achieve vertical accuracy, and offset settings (height corrections from ground to receiver) can be changed with a single button. Overall, LRTK dramatically enhances ease of use and agility on site.

LRTK Pricing Range and Implementation Costs

Affordability is another major attraction of LRTK. Conventional GNSS survey instruments with integrated antennas often cost several million yen per unit, but LRTK is available at a far more accessible price. The compact LRTK Phone device is very reasonably priced—from several ten-thousand yen to a little over one hundred thousand yen—and the dedicated app is provided for free. With only a smartphone required, you can begin high-precision surveying without investing in expensive dedicated controllers or stationary equipment. The price range allows everyone on a site to have one unit each, overturning the conventional notion that “surveying equipment is one set per team.”

LRTK is used in combination with correction data services provided by governments or private entities, and Japan’s CLAS satellite augmentation signal is available free of charge, keeping operating costs low. Even when using network RTK, the device can typically operate over existing smartphone data plans without requiring special radio equipment or paid service contracts (note: using some high-precision positioning services may require a separate contract). Peripheral services like the LRTK cloud also include basic functions within the package, so no additional software fees are required. Overall, both initial investment and running costs can be drastically reduced compared to traditional options, making LRTK accessible for small and medium-sized companies and local governments.

LRTK Use Cases (Industry and Local Governments)

What actual benefits have been observed on sites that adopted LRTK? Below are cases from the construction industry and local governments.

Efficiency Improvements on Construction Sites

At a civil engineering construction site, LRTK adoption significantly improved surveying efficiency. Work that had previously required two people and a full day to complete as-built measurements was reported to be done by one person in just a few hours after introducing LRTK, a reduction in work time of about 70% or more, leading to substantial labor cost savings. Because LRTK can acquire high-density survey data in real time, the entire site could be comprehensively measured, improving both accuracy and quality. The resulting point clouds made it possible to check locations that would have been missed with traditional spot-check surveying, contributing to early detection of construction mistakes and reducing rework.

Use by Local Governments

Local governments have also begun deploying LRTK for digital transformation of field surveys. For example, Fukui City was an early adopter of the LRTK system for disaster recovery site surveys in 2023. Because staff can start measuring with a smartphone as soon as they find damaged areas, the need to travel back and forth between the field and the office is reduced, enabling faster and more detailed recording of damage than before. As a result, lead times from recovery planning to construction start were shortened, contributing significantly to faster restoration and cost savings. The relatively low implementation cost is also attractive to local governments, and by performing surveying in-house rather than outsourcing it, they achieved cost reductions and internal skill development. LRTK-supported one-person surveying has demonstrated results in the public sector, and other municipalities are now considering adoption.

Main Benefits of Introducing LRTK

Summarizing the benefits that one-person surveying with LRTK brings to the field:

• Reduced labor costs through fewer required personnel: Tasks that previously needed two to three people can be performed by one, helping to alleviate labor shortages and substantially cut labor costs. This enables limited staff to cover multiple sites, directly improving productivity.

• Shorter working times: Fast positioning and data processing dramatically shorten lead times from surveying to drafting, quantity calculation, and reporting. Because field data can be shared to the cloud instantly, as-built verification that used to take days can often be completed the same day.

• Improved surveying accuracy and data quality: Measurements at centimeter-level accuracy (cm level accuracy (half-inch accuracy)) via RTK-GNSS provide data that meets precision requirements. Point cloud measurements enable high-density coverage of the entire site, producing high-quality deliverables without omissions. Smaller errors reduce re-measurement and rework.

• Enhanced safety: Shorter surveying times reduce workers’ on-site exposure, lowering the risk of heatstroke and accidents. Nighttime or high-traffic area surveying can be completed more quickly, minimizing time spent in hazardous situations.

• Reduced human error: Automatic recording and organization of measured values and photos eliminate transcription errors and data entry mistakes. Digital data management prevents missed or unrecorded measurements, enabling reliable deliverables.

• Ease of skill acquisition and mitigation of knowledge centralization: Smartphone-app-centric operation is easy to understand and can be learned in a short period. Because surveying know-how is systematized, work can be performed with consistent accuracy without relying on specific veterans. The process is less dependent on individual experience, enabling stable surveying across the organization.

How to Implement LRTK and How to Start Easily

Getting started with LRTK is remarkably simple. The basic steps are summarized below.

• Equipment and app preparation First, obtain the LRTK device and attach a dedicated mounting case to the iPhone or iPad you will use. Download and install the free “LRTK” app from the App Store.

• On-site setup Upon arrival at the site to be surveyed, securely attach the LRTK device to the smartphone and power it on. Launch the LRTK app and connect to the device to begin GNSS reception. Wait a few dozen seconds for satellite tracking to stabilize; when the RTK “FIX solution” (high-precision solution) appears on the screen, you’re ready to survey.

• Positioning and measurement execution Move to the desired point and tap the “measure” button in the app to record the high-precision coordinates of that location. No assistant is required. If you want to measure a wide area continuously, simply walk around holding the smartphone and point cloud scanning will be performed automatically, generating a surrounding 3D model. For stakeout or installation tasks, use the coordinate guidance function and follow the on-screen directions to identify target positions accurately by yourself.

• Checking and recording results Measured coordinate data and point clouds are displayed instantly within the app, and distance and angle calculations can be performed on the spot. Take photos as needed to save high-precision record photos tagged with positioning information. Data lists are managed within the app and can be reviewed or edited later.

• Data sharing and utilization After surveying, upload the data to the cloud with a single tap from the app. By the time you return to the office, results will already be shared with stakeholders and can be reviewed over the internet. You can receive feedback on additional measurement requests or point out mistakes on the spot, enabling immediate follow-up measurements as needed and minimizing rework.

As described above, using LRTK makes field surveying that once required multiple people remarkably easy. By leveraging GNSS and smartphones for “one-person surveying,” surveying tasks are dramatically streamlined and the instant sharing of data improves construction management accuracy. LRTK, which combines high precision and ease of use, is truly a powerful partner for promoting field DX. If you are interested, check the manufacturer’s official website and materials for more details. You will likely find that LRTK’s capabilities directly boost on-site productivity. Why not experience the simplicity of one-person surveying that can be started with just a smartphone?