Field DX Starts with Surveying! How i-Construction Is Changing the Norms of Solo Surveying

Amid the rapid digital transformation (DX) of construction sites, the key to field DX is to start with “surveying”. Accurate site data obtained from surveying can be used consistently through subsequent construction and inspection phases, so early-stage DX directly improves productivity across the site. In particular, the government-led [i-Construction](https://www.mlit.go.jp/tec/i-construction/index.html) initiative has made the formerly unthinkable practice of “solo surveying” a realistic option. This article explains the outline of i-Construction and its relationship with surveying DX, the background driving the need for solo surveying, how RTK technology and smartphone use are changing surveying, the benefits of using survey data consistently through construction and inspection, and the advantages of new technologies that even young or non-survey professionals can handle. Finally, using the latest smartphone surveying solution LRTK as an example, we show how solo surveying can accelerate field DX.

What is i-Construction? Its Relationship with Surveying DX

i-Construction is a productivity improvement project for construction sites promoted by the Ministry of Land, Infrastructure, Transport and Tourism since 2016. It aims to introduce ICT (information and communication technology) comprehensively across all processes from surveying, design, construction, inspection to maintenance, improving quality and safety while reducing labor and time for greater efficiency. The initiative responds to increasing construction demand (Tokyo Olympics, World Expo, aging infrastructure countermeasures, etc.) and industry challenges such as an aging workforce and a shortage of young skilled workers, which have stalled productivity for years. As part of a “productivity revolution,” the government has strongly promoted i-Construction to establish new industry standards.

One pillar of i-Construction is DX in surveying and construction. For example, in earthworks, a combination of drone automated flight surveying, machine guidance-equipped construction machines, and automated as-built (quantity) management has been adopted, with a target to improve construction site productivity by 20% by fiscal 2025. The use of 3D data from initial topographic surveys through progress management during construction to final inspections is recommended, and technologies such as 3D laser scanners, photogrammetry, and GNSS positioning have been introduced on many sites. In 2024, an expanded version called “i-Construction 2.0” was formulated, calling for further automation of construction sites. This includes reports of the spread of new measurement technologies such as simple yet high-accuracy 3D surveying using smartphone apps, which are expected to greatly contribute to efficiency and labor savings in surveying. In short, i-Construction is a driving force accelerating “surveying DX,” the starting point of field DX.

Site Challenges and Background Driving the Need for Solo Surveying

Until now, surveying work has been routinely conducted by multiple-person teams. Typically, one person operates surveying equipment like a total station while another stands at a distant point holding a staff (level rod) or prism—this division of labor requires coordinated teamwork and considerable time and effort for setup and takedown. When there are many survey points or a wide area, it was not uncommon for surveying alone to take an entire day. Because surveying relied on manual, analog work, there was also a risk of human error; mistakes reading staff markings or handwritten recording errors could force re-measurement in later steps, increasing costs and delaying schedules. Due to this burden, many sites measured only the apparently important spots, leaving risks of unforeseen problems from omissions.

In recent years, however, the construction industry has faced chronic labor shortages and an aging skilled workforce. As experienced surveyors decrease and fewer young people enter the field, reducing personnel and improving efficiency in surveying have become unavoidable. Continuing “people-dependent surveying” has become difficult, and there is a strong demand for new methods that allow highly accurate surveying with few people. In this context, an approach called “solo surveying” using ICT technologies has attracted attention. Government-led promotion of i-Construction and the broader construction DX trend have supported this shift, changing the norm that “surveying must be done by a team.” From the field, voices are emerging that “if one person can measure accurately, it’s more efficient,” and solo surveying is becoming the new normal in the era of labor shortages.

How RTK Technology and Smartphones Are Changing Surveying Styles

The main technological enabler of solo surveying is the advancement of GNSS positioning technology. GNSS, represented by satellite signals like GPS, has long been used in surveying, but standalone positioning typically yields errors of several meters—insufficient for construction sites that require decimeter-to-centimeter accuracy. The solution is *RTK* (Real Time Kinematic). RTK links a mobile rover and a base station at a reference point via communication and applies real-time differential corrections for common error factors, dramatically improving positioning accuracy. This enables instant centimeter-level positioning, and since the 1990s RTK has spread as an alternative to total stations.

Conventional RTK-GNSS equipment tended to be expensive, bulky, and required expertise to operate. Setting up a dedicated base station and radio communication equipment raised the preparatory hurdles, so despite high accuracy they were not truly convenient for labor reduction. Recently, however, miniaturization and cost reduction of RTK-GNSS devices have advanced, and ultra-compact receivers that work with smartphones have appeared. For example, a pocket-sized RTK receiver that can attach to a smartphone—such as the aforementioned [LRTK](https://www.lrtk.lefixea.com/lrtk-phone)—weighing only about 100–125 g eliminates the need to carry a tripod or long staff, allowing a single operator to perform high-accuracy surveying while moving around the site. Antennas and batteries required for positioning fit in one hand, enabling agile movement even in confined or sloped areas, and reducing physical burden for older or less strong workers.

Moreover, smartphone apps have transformed surveying styles. Smartphones offer intuitive interfaces that younger workers accustomed to smartphones can handle without resistance. On a dedicated app, tapping a button completes positioning and recording; complex settings and calculations are automated, so accurate data can be obtained without specialized surveying knowledge. For example, touching the pole tip-mounted device to the point to be measured and pressing the app’s “Measure” button records the latitude, longitude, and elevation at centimeter accuracy. The data are immediately saved on the smartphone, with date/time, point name, and positioning status (such as fixed solution/FIX) automatically recorded, enabling error-free and reliable data capture. Apps also perform conversions to Japan’s plane rectangular coordinate system and geoid height corrections, so users don’t need knowledge of coordinate computations. In short, machines and software take care of the complex behind-the-scenes processing, and field workers increasingly only need to “place the device on the point and press the button.”

This kind of real-time, simple surveying not only reduces manpower but also dramatically speeds up operations. Because one person can measure on the spot when needed, work is no longer interrupted waiting for the surveying team to be arranged. Instant measurement and data sharing mean reduced waiting for setup and faster decision-making. For example, a survey that used to take two people half a day might be completed by one person within a few hours, greatly reducing total labor hours and giving more leeway in the overall schedule. If acquired data are shared with the office in real time via the cloud, supervisors or colleagues can be notified and give instructions from a distance. Thus, the combination of RTK technology and smartphones enables a new surveying style that achieves both labor reduction (fewer personnel) and real-time capability, reshaping the norms of surveying in field DX.

Benefits of Using Survey Data Consistently Through Construction and Inspection

High-accuracy digital survey data obtained via solo surveying can be used consistently in subsequent construction planning and quality inspection. This is a key way that surveying DX contributes to overall field DX. Traditionally, inefficiencies occurred when handwritten field notes were transcribed into CAD drawings at the office or when separate measurements were taken after completion to create as-built drawings. But when initial survey data are digitized and shared via the cloud, handoffs to later stages become seamless.

Specifically, point cloud data and coordinate information obtained from surveys can be imported directly into design software for earthwork volume calculations and construction planning. It becomes easy to overlay current 3D terrain models with 3D design data to simulate construction steps and share the completed image among stakeholders. During construction, periodic solo surveys can be used to measure the current status and check differences from the design model so that whether the as-built shape matches the design can be verified at a glance. Displaying point cloud data with color-coding visualizes areas of excess or deficiency in fill or excavation, allowing early detection of areas that need rework. This leads directly to higher-quality management and prevents rework.

If the latest survey data are continuously uploaded to the cloud, remote site attendance from the office becomes possible. For example, high-accuracy point clouds or 360-degree photos captured with a smartphone can be shared in the cloud and reviewed by headquarters engineers in a VR space. Smoother information sharing with remote parties facilitates explanations and negotiations with clients, speeding up consensus building. At project completion, comparing pre- and post-construction data enables rapid creation of digital deliverables for electronic submission. Being able to comply with i-Construction’s digital deliverable requirements simplifies interactions with clients and inspectors.

Thus, implementing DX at the surveying stage not only streamlines surveying tasks but also raises productivity across construction and inspection processes. By fully utilizing the initial survey data through to the end, duplicate work and data inconsistencies are reduced, and the entire site becomes faster and higher quality. This truly embodies the concept that “field DX starts with surveying.”

Advantages as a Field Technology Usable by Young and Non-Survey Personnel

A major strength of the latest solo surveying technologies is that they are easy to use even for people without special skills. On-site, not only survey specialists but also construction managers and tradespeople can perform measurements themselves, broadening the scope of tasks. Smartphone-based surveying using ICT offers benefits to young employees and staff in non-survey roles. Key advantages include:

• Intuitive and easy operation: Because the tools run on smartphone apps, people familiar with smartphones can use them without confusion. Following on-screen prompts and pressing a button completes measurements, while complex settings and calculations are handled automatically in the background. Newcomers can learn the basic operations with a short lecture and start using them on site the same day.

• Small, lightweight equipment with low burden: There is no need to carry heavy optical surveying instruments or tripods; a smartphone and a small GNSS device suffice. Devices weighing a few hundred grams are easy for even older veteran workers to carry. Since they can be carried on-site routinely, minor spot checks can be done casually, preventing missed measurements or delays and contributing to improved safety.

• High accuracy even with limited surveying knowledge: Apps clearly display current positioning accuracy and satellite reception status, and warn when accuracy is unstable, enabling users to understand the situation while working. The acquired coordinate data are automatically converted to public coordinate systems, so even without specialized knowledge users can obtain high-quality measurement results without errors. Less experienced staff can deliver results close to those of veterans, helping to level up organizational technical capability.

• Multitasking for site records: Smartphone surveying devices are capable of more than just recording point positions. For example, they can capture surrounding point clouds by combining the phone’s camera or LiDAR, or use AR (augmented reality) to project design lines from electronic drawings onto the site for stakeout. One person can survey while simultaneously taking photos or checking as-built status, compressing workflows and improving efficiency.

In this way, solo surveying technology is no longer the exclusive domain of specialists. Digital-native younger generations—and even veteran workers who are not comfortable with digital tools—will be impressed once they experience the convenience of “measuring with a single button.” When all field staff can use the technology, surveying becomes a more routine, everyday task, enabling the right person to respond immediately when needed.

Example of Smartphone Surveying Implementation: How LRTK Brings a Solo Surveying Revolution

Now let’s look at an implementation example that achieved field DX through solo surveying. At a certain mid-sized construction site, a smartphone-mountable RTK positioning system [LRTK](https://www.lrtk.lefixea.com/lrtk-phone) was introduced to replace the conventional two-person surveying team. As a result, surveying man-hours were reduced by 30% in the first week, and substantial ongoing productivity gains were reported. Site personnel noted that after introducing LRTK, “fewer people were needed for surveying, so manpower could be reallocated to other important tasks. Because we can measure immediately as the need arises, there’s no waiting, enabling both schedule shortening and quality improvement.”

LRTK was developed by a startup originating from Tokyo Institute of Technology as a smartphone-integrated ultra-compact RTK-GNSS receiver. About 13 mm thick and weighing roughly 125 g, it can be attached to an iPhone or iPad and enables centimeter-level positioning on its own. It includes a dedicated app and cloud service that plot acquired positions on cloud maps for instant internal sharing. LRTK supports network RTK (Ntrip), receiving correction data from nationwide reference station networks via the smartphone’s 4G/5G connection. In areas without network coverage, such as mountainous regions, it can use Japan’s quasi-zenith satellite system QZSS’s high-precision augmentation signal (CLAS) to obtain corrections, allowing continued positioning even where the internet is unavailable.

LRTK is designed so that anyone can easily perform solo surveying. At the aforementioned site, a first-year employee handled surveying with LRTK and quickly got the hang of it, much like playing a smartphone game. From checking positioning status to saving data and sending it to the cloud, everything is done with a tap, eliminating the need for paper field notebooks. The results can be imported directly into BIM/CIM and CAD software, facilitating design comparisons and creation of as-built documentation. LRTK is a prime example of a solution that has dramatically improved survey accuracy and efficiency on-site.

Solutions that meet the requirements of i-Construction, like this one promoted by the Ministry of Land, Infrastructure, Transport and Tourism, are being adopted by construction companies and local governments nationwide. Introducing even a single smartphone surveying device such as LRTK to a site will let you experience its immediate effects. Start with trial operation on small sites or projects to gauge the benefits, and then gradually expand use. Surveying DX can be the trump card for solving labor shortages and boosting productivity across sites. “Field DX starts with surveying”—why not actively adopt the latest technologies and establish the new norm of solo surveying to realize smarter construction management unconstrained by past conventions?