Boost Surveyors’ Work Efficiency with Just a Smartphone! How to Use LRTK Phone and Its Benefits

Field challenges for surveyors: squeezed between labor shortages and precision demands

On construction sites, surveying by surveyors and site managers is an indispensable daily task. However, in recent years the field has faced a serious labor shortage. While experienced surveyors are decreasing due to aging, infrastructure maintenance and construction demand are increasing, and it is not uncommon for a single surveyor to cover multiple sites. As a result, site responsiveness leads to long working hours and increased pressure to perform high-precision surveys quickly.

There are also heavy burdens in traditional surveying operations themselves. For example, surveying with a total station required carrying tripods and heavy equipment and always working in pairs. Equipment inspection and calibration take time and cost money, and regular maintenance by sending devices back to the manufacturer is indispensable. GNSS surveying equipment exists, but ordinary single-receiver positioning typically produces errors of about 5–10 m (16.4–32.8 ft), making it difficult to use for precision construction surveying. Although rapid, high-precision measurements are required on site, these traditional methods suffered from issues of equipment burden, securing personnel, and guaranteeing accuracy.

The advent of smartphone surveying: DX that anyone can use

A promising solution to these on-site situations is a new surveying method that uses smartphones. Advances in ICT have dramatically improved the performance of GPS, cameras, and LiDAR sensors built into smartphones and tablets. In Japan, the Ministry of Land, Infrastructure, Transport and Tourism is promoting construction DX such as i-Construction, strongly supporting digitalization and labor reduction on sites.

Solutions like the recently introduced "LRTK Phone" combine a smartphone with high-precision GNSS to achieve surveying accuracy comparable to dedicated surveying equipment while retaining the ease of smartphone apps. Tasks that previously required specialized surveying instruments or qualifications can increasingly be performed easily by on-site workers and site managers themselves using smartphone surveying. If a familiar tool like a smartphone allows everyone to participate in surveying, it can help alleviate chronic labor shortages.

Behind this is the spread of RTK (Real Time Kinematic), a high-precision satellite positioning technology. RTK reduces errors to a few centimeters (a few cm (a few in)) by positioning using a reference station and a rover, and miniaturizing this to work with smartphones has opened the door to turning smartphones into surveying instruments. Improvements in AR (augmented reality) that overlay 3D models onto camera images and advances in LiDAR 3D scanning have also accelerated the digitalization of surveying work.

What is LRTK Phone: a surveying style transformed by smartphones

"LRTK Phone" is a next-generation smartphone surveying system consisting of a small device that attaches to smartphones such as iPhones and a dedicated app. By simply attaching an RTK-GNSS receiver that weighs only a few hundred grams and fits in your pocket, a site gains centimeter-level positioning accuracy (cm level accuracy (half-inch accuracy)). No complicated equipment setup is required—start the app on the smartphone screen and surveying can begin immediately.

Key features of LRTK Phone are summarized below:

• High-precision RTK positioning: With a dedicated antenna and real-time corrections, it achieves positioning accuracy of approximately ±1–2 cm (±0.4–0.8 in) (up to about ±3 cm (±1.2 in) in height), which ordinary smartphone GPS cannot reach. Latitude, longitude, and height can be obtained in the site’s surveying coordinate system, allowing benchmarks and height measurements to be completed with a smartphone. Reports indicate that Fix solutions (high-precision positioning) can be obtained stably even in challenging environments such as mountain areas, offering accuracy comparable to conventional equipment.

• Palm-sized & single-person operation: The smartphone and small receiver set is extremely compact and overwhelmingly lighter than conventional fixed GNSS units or total stations. It is portable enough to "carry with you at all times" on site, enabling measurements whenever needed. Because one person can carry and operate the equipment, surveying tasks that previously required two people can be completed by a single person.

• Built-in battery for long operation: The device itself has a built-in battery that allows about 6 hours of continuous use. It can be charged from a mobile battery via USB Type-C, so long surveys or sites where power is hard to secure are not a problem. It connects wirelessly to the smartphone, eliminating cable clutter.

• Diverse surveying app functions: The dedicated app integrates a variety of useful on-site functions. Single-point positioning (measuring coordinates for individual points) can be executed with a single button, and measurement date/time and GNSS reception status are automatically recorded. Acquired coordinates are instantly converted and displayed in Japan’s plane rectangular coordinate system or the World Geodetic System (WGS84), and on-site note input is supported. In continuous positioning mode, you can record a track while walking to capture road alignment or ground elevation. An averaging positioning function allows multiple measurements at the same point to improve accuracy with a single tap.

• Cloud integration and automatic recording: Data measured on site can be synchronized to the cloud directly from the smartphone. Office PCs can access the data via web browser to check measurement results in real time. Coordinates and point cloud data are automatically plotted on 2D maps or 3D viewers in the cloud and can be shared with the whole team. This eliminates the need to bring data back via USB or SD card and significantly streamlines office documentation work.

• 3D scanning & point cloud processing: By utilizing the smartphone’s built-in LiDAR sensor and camera, surrounding structures and terrain can be captured as 3D point cloud data. With LRTK, high-precision coordinates are attached to each point, so there is no worry about point cloud distortion or scale errors during scanning. Acquired point clouds can be displayed immediately on the smartphone, and you can measure distances between any two points, calculate areas, and even compute volumes on site. Being able to perform point cloud processing on site—previously requiring specialized software—is a major advantage.

• AR-guided positioning & design overlay: LRTK Phone also features AR-based position guidance. Select a target coordinate set up in the cloud in advance, operate the app on site, and navigation displays appear on the screen. Following arrows or guide indicators will lead you to the target point to centimeter accuracy (cm level accuracy (half-inch accuracy)). This is powerful when locating stake positions or boundary markers. Based on previously acquired data, you can also remeasure or reshoot the exact same location and orientation as before, making fixed-point observations and long-term change detection dramatically easier.

• Geotagged photo function: Photos taken with the smartphone camera can be linked to LRTK high-precision coordinates. The shooting location (latitude, longitude, height) and camera orientation are automatically recorded with each photo and plotted as photo icons on the cloud map. This replaces the cumbersome workflow of taking photos with a digital camera, writing positions on paper maps, and organizing photos in the office—on-site the job is completed by simply pressing the shutter. Text notes can be attached to photos, so inspection results can be recorded on site and shared to serve as electronic reports. This innovative function eliminates position recording errors and the burden of photo organization.

As described above, LRTK Phone provides multifaceted functions as an all-in-one surveying tool that completes positioning, recording, and sharing with just one smartphone. Next, let’s look concretely at how it can be used on site.

How to use LRTK Phone: expanding smartphone surveying on site

• Guiding stake driving and layout marking: LRTK Phone’s AR guidance is useful for setting out stake positions required for foundation work. Traditionally, a surveyor would set out positions based on drawing coordinates and sometimes another person would place stakes while tracking angle and distance with surveying equipment. With smartphone surveying, the device navigates to pre-set stake positions, and on site you can identify stake locations by following arrows and AR markers on the screen. Because a single worker can intuitively perform accurate staking, workers alone can carry out layout marking. In locations where physical staking is impossible (hard ground or slopes), virtual stakes can be placed in AR to indicate locations for pre-planning or verification of as-built conditions.

• Infrastructure inspection and maintenance: Smartphone surveying is also powerful for routine inspections and maintenance of roads, bridges, and facilities. High-precision geotagged photos taken with LRTK Phone accurately record crack locations on bridges or deformations on road signs, allowing the same spot to be reliably found at the next inspection. For example, even if the inspector changes after one year, loading previous data into a device and using coordinate navigation lets anyone reach the same inspection point without hesitation. In AR mode, pointing the camera in the same orientation as a previous capture enables real-time comparison with past photos. This facilitates quantitative assessment of deterioration and promotes digital asset management (electronic medical records) for infrastructure. Using 3D point cloud scans makes it easy to measure deformations of tunnels or retaining walls over time, improving maintenance quality.

• Disaster response and emergency surveying: In the event of earthquakes, heavy rain, or other disasters, quickly and accurately grasping damage is essential. LRTK Phone is extremely useful in disaster response. Its small size and mobility allow responders to reach disaster sites faster than anyone else to survey and record damage. For example, you can plot ground cracks with high precision or 3D-scan collapse sites and share them to the cloud immediately so relevant organizations instantly share situational awareness. Traditionally it took time for surveying teams with equipment to arrive, but smartphone surveying dramatically improves initial response speed. Some local governments have introduced LRTK Phone for disaster surveys and greatly shortened report preparation time using automatic photo organization. In emergencies, smartphone surveying’s ability to capture sites despite labor shortages is especially valuable.

• Everyday quick measurements and as-built verification: Beyond special occasions, smartphone surveying contributes to efficiency in daily construction management for small measurement tasks. For example, when an equipment operator or site supervisor wants to confirm excavation depth or embankment volume during construction, scanning the current state with a smartphone and comparing it to the design model in the cloud enables on-the-spot calculation of deviations (such as earthwork volumes). This allows immediate judgments like “is excavation on plan?” or “how many cubic meters of soil are still needed?”, preventing rework and delays in material procurement. If you suddenly need a dimension on site, there’s no need to fetch a tape measure or level; LRTK Phone can instantly measure the distance between two points or the elevation difference on the smartphone screen. Accumulating these small daily efficiency gains leads to improved productivity across the entire project.

Efficiency improvements brought by smartphone surveying

Introducing smartphone-based surveying methods dramatically improves on-site work efficiency in many ways. Key improvement points are summarized below:

• Significant reduction in work time: Time spent installing and packing up equipment is dramatically reduced. For example, surveying with a total station required tens of minutes for set-up and teardown each time, whereas smartphone surveying allows almost zero preparation time and immediate measurement. Multiple stake positions can be navigated sequentially to improve travel efficiency, reducing total time per measurement point. Post-processing and drawing production are automated in the cloud, dramatically shortening both on-site and office post-processing time.

• Effective use of personnel (labor reduction): As tasks that can be completed by one person increase, personnel allocation becomes more flexible. Surveying work that typically required two people can be done by one, maintaining site responsiveness even under labor shortages. If a staking survey that used to require two people can be done by one, the other person can be assigned to other important tasks, enabling more work to be completed with limited personnel. LRTK Phone’s intuitive operation also reduces training costs, allowing non-specialist site staff to handle routine measurement tasks. As a result, surveyors can focus on critical checks and difficult surveys, raising overall team productivity.

• Improved accuracy and fewer mistakes: Centimeter-level accuracy from RTK reduces rework and backtracking caused by measurement errors. Mistakes in staking are reduced, and risks of misalignment or rework for installed structures are minimized. Automated data recording prevents human errors such as transcription mistakes from handwritten notes or mislabeling photos. Stable, accurate digital data remains available, eliminating cases where “the reference point coordinates were lost” or “we don’t know where this photo was taken,” and avoiding the need for repeat surveys. Improved accuracy and reliable records provide major benefits for quality assurance.

• Improved safety: The ability to work solo also benefits safety. A smaller crew can cover wide sites without staying long in hazardous areas. Targeted geotagging and AR technologies allow remote measurement without entering dangerous zones. For example, tasks that previously required a worker to stand on the roadway can now be done from a safe distance by pointing a camera and obtaining coordinates. Reductions in nighttime and high-elevation work are expected, lowering the risk of occupational accidents while improving efficiency.

• Reproducibility and effective use of data: Digital measurement data accumulated and shared over time allows the construction of highly reproducible work cycles. Recording daily construction progress as point cloud data lets you accurately look back at any day’s conditions. Comparing past and present data for quantitative evaluation is simple. This not only strengthens arguments for design changes and quality verification but also contributes to knowledge sharing. Measurement data and notes accumulated by experienced personnel become an organizational asset via the cloud and serve as valuable references for future projects.

Quantitative benefits compared to traditional methods

The effects of smartphone surveying can be visualized by comparing them with traditional surveying methods. Key differences in major items are summarized below:

• Required equipment and gear: Total stations and high-precision GNSS equipment required transporting heavy tripods, controllers, and antennas by vehicle. In contrast, LRTK Phone needs only a smartphone plus a small antenna. This greatly reduces on-site transport burden and logistics costs. The more compact the equipment, the easier it is to bring it into remote mountain sites or confined urban sites.

• Survey personnel: Traditionally a two-person team (surveyor + assistant) was the norm—for example, one person operating the instrument while another held a staff or prism at the measured point. With smartphone surveying, both basic operation and point indication are completed on the device screen, so in principle one person can finish the job. Even with limited personnel, you can cover sites with a minimal crew.

• Survey accuracy: Ordinary smartphone GPS or handheld GNSS inevitably produce errors on the order of meters, making fine staking impractical. Precision positioning previously handled by first-class GNSS instruments or EDMs can be achieved by LRTK Phone with the same centimeter-level accuracy (cm level accuracy (half-inch accuracy)). Experiments report differences from high-precision GNSS terminals of a few millimeters or less (a few mm or less (≤0.12 in)). In other words, despite being a smartphone solution, it can be expected to provide surveying-grade accuracy.

• Initial investment and running costs: High-performance surveying instruments require investments of several million yen and annual inspection costs. LRTK Phone leverages existing smartphones, keeping introduction costs down, and cloud services are subscription-based for only the needed period. While specific pricing is omitted here, it is generally far more economical than procuring multiple high-end surveying instruments, making one-device-per-person deployment realistic. An era in which everyone carries a surveying tool is becoming feasible.

• Data processing flow: Traditionally, coordinates obtained on site had to be written in notebooks and then manually entered into drawing software back in the office—an analog plus manual workflow. With smartphone surveying, measured data is saved to the cloud instantly and is automatically plotted and listed. Sending a shared link allows stakeholders immediate access, speeding up reporting and inspections. Reducing paper usage also yields secondary environmental benefits through paperless processes.

From these comparisons, it is clear that smartphone surveying with LRTK Phone is superior to traditional methods in terms of physical burden, personnel requirements, time costs, and monetary costs. It truly represents a paradigm shift in the surveying field.

How adopting LRTK changes the surveyor’s role and future prospects

As smartphone surveying is adopted on site, the role and working style of surveyors will change. In short, it’s a shift from “craftspeople who operate heavy equipment” to “specialists who handle digital data.”

Traditionally, surveyors emphasized the skill of setting up equipment and measuring accurately on site. With tools like LRTK Phone, physical burdens are reduced, allowing surveyors to devote more time to data analysis and utilization. Surveyors can delve into added-value tasks such as analyzing terrain changes using point cloud data or visually explaining designs to designers and clients using AR models.

Because anyone will be able to perform basic surveying, surveyors’ roles will increasingly include being on-site “data managers” and “accuracy supervisors.” Even if site staff collect data themselves, surveyors with specialized knowledge will check data quality, correct it to the proper coordinate system, and interpret analysis results, thereby ensuring overall data accuracy. In other words, surveyors may become the hub that collects surveying information from everyone on site and elevates it into valuable information.

Looking ahead, the spread of smartphone surveying will directly promote construction DX. High-precision real-time data can integrate with BIM/CIM 3D models and GIS systems to reproduce the entire site as a digital twin. Surveyors will operate these digital platforms and supervise AI-based automatic analyses, expanding into new knowledge domains. This shift makes surveying an attractive, advanced profession for younger generations who use IT skills, aiding recruitment and knowledge transfer.

Conclusion: Start easy, high-precision smartphone surveying with LRTK Phone

Smartphone surveying has become an unavoidable trend to address labor shortages, work style reforms, and increasingly sophisticated site needs. Among solutions, LRTK Phone combines ease of use and reliable accuracy and is being adopted at many sites. It benefits not only surveyors but also site managers and design engineers; it has the potential to change on-site conventions.

Of course, not all surveying tasks can be done with a smartphone alone, and conventional precision equipment and expert knowledge will still be necessary in some situations. However, even if smartphones can handle the majority of routine surveying and measurement, they will significantly reduce on-site burdens and improve efficiency. Experience the surprise of “can so much be done with just a smartphone?” firsthand. Smartphone surveying using LRTK Phone will substantially change how surveyors work and boost construction site productivity. To avoid missing that wave, we recommend picking one up and trying it out on site.