Surveying Innovation in the i-Construction Era: Improving Productivity with Drones & Smartphones

The construction industry is now experiencing an unprecedented revolution in the field of surveying. Under the banner of the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction, cutting-edge surveying techniques that leverage familiar tools such as drones (unmanned aerial vehicles) and smartphones are gradually taking root on job sites. These technologies have the potential to solve problems such as labor shortages and heavy workloads and to dramatically improve productivity. This article focuses on the surveying domain, explaining the overview and background of i-Construction, the emergence of drone surveying and smartphone surveying (RTK technology), and practical changes brought by point cloud data processing and the use of AR and cloud services. It also presents the effects of labor savings and shortened construction schedules through recent field examples, and finally touches on the benefits of an easy-to-introduce smartphone surveying solution, LRTK.

What is i-Construction: Background and Objectives in the Surveying Field

i-Construction is an initiative proposed by the Ministry of Land, Infrastructure, Transport and Tourism from fiscal 2016 to revolutionize productivity on construction sites【[Ministry of Land, Infrastructure, Transport and Tourism i-Construction](https://www.mlit.go.jp/tec/i-construction/index.html)】. It aims to fully utilize ICT (information and communication technologies) across the entire construction production process—from survey and measurement through design, construction, inspection, maintenance, and renewal—to simultaneously realize operational efficiency and workstyle reform by improving individual work productivity. Concretely, it seeks to proceed with safe and rapid construction by utilizing 3D data, introducing new surveying methods such as drones and laser scanners, and employing ICT-enabled construction machinery (machine guidance and machine control).

The background includes a decrease in construction engineers due to low birthrates and an aging population, challenges in skills transfer, and the goal of transforming construction sites—traditionally seen as the “3Ks” (kitanai, kiken, kitsui: dirty, dangerous, and demanding)—into workplaces attractive to younger people. The government has set a goal of improving construction site productivity by 20% by fiscal 2025, and has also drawn up a roadmap aiming for 1.5 times productivity (30% labor saving) by fiscal 2040 as “i-Construction 2.0.” The surveying field has drawn particular attention as a first step, with expectations that digitalization and automation of traditionally labor-intensive surveying tasks will greatly reduce workload while achieving both accuracy and speed.

Traditional on-site surveying relied on experienced surveyors setting up transits or total stations and staffs holding rods to measure many points. Surveying large sites or complex terrain required many days and manpower and carried risks of working in hazardous locations. In the i-Construction era, this is changing dramatically. Innovative methods such as drone aerial photogrammetry and smartphone surveying using RTK-GNSS now allow anyone to acquire on-site 3D data safely and with high accuracy in a short time. In the following sections, we will take a closer look at the basics and effects of these new technologies.

What is Drone Surveying? Basics and Effects of Aerial Photogrammetry

A key element when discussing i-Construction is drone (UAV) surveying. The basic principle of drone surveying is to capture numerous photos of the site from the air with a high-resolution camera mounted on a drone, then analyze them using photogrammetry to generate accurate terrain models and orthophotos. The captured images include position information from GPS and RTK, and specialized software or cloud services calculate 3D coordinates from overlapping photos to produce high-density point cloud data and detailed terrain maps. In some cases, drones are equipped with laser scanners (LiDAR) to directly acquire 3D point clouds, but camera-based aerial photogrammetry has become widespread at many sites for cost reasons.

Benefits of drone surveying: Data that previously required days of ground-based manual measurement can be acquired all at once by drone in a short time (several hours to about a day). For example, earthwork sites that used to require several days of detailed ground point collection can be flown by drone to collect tens of millions of points from above, and in some cases a detailed 3D terrain model can be constructed in as little as half a day. This not only enables significant reductions in construction schedules, but because survey density is overwhelmingly higher than manually collected points, subtle undulations and earthwork volumes can be accurately grasped.

Improved safety is another major benefit. Drones can record conditions remotely even in steep slopes, cliffs, or areas with operating heavy machinery where it would be dangerous for people to enter. Because surveyors no longer need to descend into hazardous locations or perform staking (layout marking) near operating heavy machinery, the risk of occupational accidents is reduced. In fact, cases report that introducing drone surveying in mountainous sites with steep slopes made it almost unnecessary for workers to enter high-slope areas, dramatically improving safety.

Moreover, precise 3D data acquired by drones is useful for subsequent design and construction management. The orthophoto captured can be used as an as-built plan view, and cross-sections can be extracted from generated point clouds, which can be used for archaeological surveys or as-built verification. The Ministry of Land, Infrastructure, Transport and Tourism has long prepared guidelines (draft) for as-built management using drone photogrammetry to promote drone use for earthwork as-built measurement. This makes it easy to perform embankment and excavation volume calculations from aerial imagery, dramatically improving what had previously been manual earthwork quantity management.

The Rise of Smartphone Surveying and the RTK Positioning Revolution

Alongside drones, the emergence of surveying using smartphones deserves attention. Recent smartphones have not only improved camera and sensor performance but also greatly enhanced GNSS (Global Navigation Satellite System) reception capability. In particular, the spread of RTK (Real Time Kinematic) high-precision positioning technology has sparked a revolution whereby smartphones are evolving into surveying instruments.

What RTK positioning is: Conventional GPS positioning has errors on the order of several meters, but RTK obtains centimeter-level position accuracy by computing in real time the differences between the satellite signals received simultaneously by a base station (reference) and a rover (mobile receiver), thereby cancelling out errors. Historically, RTK surveying required dedicated survey-grade GNSS receivers and radio equipment costing hundreds of thousands of yen and specialized operational knowledge. Today, by attaching a compact RTK receiver to a smartphone or by utilizing dual-frequency GNSS chips built into smartphones, a smartphone can function as a high-precision GNSS surveying device.

Supporting this smartphone surveying revolution are nationwide GNSS reference station networks and services that distribute real-time correction information. By receiving network RTK (VRS) correction data via mobile communication, a smartphone can measure positions with centimeter accuracy (cm level accuracy (half-inch accuracy)) without preparing a dedicated base station. Additionally, Japan’s quasi-zenith satellite system “Michibiki” provides CLAS (Centimeter-Level Augmentation Service) that allows reception of correction data from satellites even outside communication coverage, enabling smartphone RTK surveying in mountainous areas. With this technical infrastructure in place, the environment where “you can perform precision surveying with just a smartphone” is becoming a reality.

Benefits of smartphone surveying: The greatest advantages are its ease of use and portability. Using a smartphone that fits in a pocket, surveying can be completed by a single operator. For example, GNSS surveys that traditionally required two people can be done by one person with a smartphone and a small receiver. Heavy tripods and mounting equipment are unnecessary. Intuitive smartphone app interfaces make them easy for site staff to operate even if they are not professional surveyors. Because high-precision coordinates are available in real time, positions can be confirmed on the spot and work can proceed immediately, greatly speeding up workflows.

Smartphones also incorporate cameras, accelerometers, and electronic compasses, allowing combined data capture such as taking photos with embedded position information or overlaying virtual models on measured points with AR technology. Previously, surveying required multiple tools—measuring with survey instruments, taking photos, writing notes—but smartphone surveying can perform all of these tasks with a single device. It is not an exaggeration to say that the entire surveying workflow has been transformed.

Practical Changes from Point Cloud Processing, AR, and Cloud Utilization

With the introduction of new technologies, methods for utilizing post-survey data and managing sites have also begun to change significantly. In particular, the use of 3D point cloud data, AR (Augmented Reality), and cloud services are keys to streamlining and advancing surveying operations and subsequent processes. Below are the changes each of these technologies brings to the field.

• Utilization of 3D point cloud data: Point cloud data obtained from drones, terrestrial laser scanners, or smartphone photogrammetry represent a digital replica of site terrain and structures composed of countless measured points. They contain vast amounts of information, including details that traditional plan or sectional drawings could not capture, and are powerful for comparing with design drawings and as-built (work quantity) management. For example, checking whether an embankment’s slope after construction matches the design using point cloud data allows immediate identification of areas requiring rework. Using point cloud processing software or cloud-based tools, differences from design data can be intuitively visualized with color-coded heat maps, improving quality control accuracy and streamlining as-built inspections.

• On-site use of AR technology: AR (Augmented Reality) overlays 3D data on live site imagery viewed through tablets or smartphones. Displaying as-is point cloud models or 3D design models in AR realizes a “fusion of digital and real” on site. For example, if underground utilities are scanned and digitized in advance, AR can project them onto the ground during subsequent excavation, immediately indicating locations that must not be dug. AR is also used to overlay planned structure models on a site before construction so that clients and nearby residents can visualize the finished appearance. AR enables information that is hard to convey with drawings or numbers to be shared visually, reducing communication losses and speeding decision-making.

• Integration with cloud services: Cloud utilization of surveying data is becoming commonplace. Previously, data collected on site had to be brought back on USB drives for office-based analysis and drafting. Now, point cloud data and survey point information can be uploaded directly from smartphones or tablets to the cloud and shared instantly within and outside the company. A remote office engineer can review the day’s data and make design adjustments the same day, and the site can download the latest data the next day—enabling real-time collaboration. Heavy computations (photo-to-3D processing or large data analyses) can be executed on the cloud, so deliverable creation is not limited by on-site PC performance. Survey data accumulated in the cloud can also be used for future maintenance management, comparison over time, and knowledge sharing across sites. Cloud integration is evolving surveying operations into a seamless process that transcends the boundaries between site and office.

Examples of Labor Savings and Shortened Schedules on Surveying Sites

What effects have the technological innovations introduced so far produced on actual surveying sites? Below are some concrete outcomes of labor savings and shortened schedules from projects that adopted i-Construction early.

• Dramatic reduction in work time: In civil works that adopted ICT construction, the Ministry of Land, Infrastructure, Transport and Tourism reported that “total man-hours from preliminary survey to construction completion were reduced by an average of about 30%.” Even limited to surveying processes, there have been cases where work time was shortened to a fraction of the conventional duration. For example, an initial terrain survey that usually took about four days for a road project was completed in just half a day after introducing drone aerial photogrammetry. In another case, use of UAVs reduced the initial survey period from one week to two days. Such dramatic reductions in surveying duration allow earlier commencement of construction and lead to shorter overall schedules.

• Labor savings and effective personnel allocation: New technologies also reduce required personnel and allow reallocation of labor. In the aforementioned road project, two workers had been tied up 1.5 days each every week for surveying and staking, but ICT made these manual tasks almost unnecessary. As a result, freed-up personnel could be assigned to other tasks, improving the efficiency and work environment for prime contractor staff. Automation and labor-saving in surveying enable projects with a shortage of technicians to operate with fewer people, contributing to easing labor shortages and reducing overtime.

• Improved safety: The use of drones and remote surveying equipment has greatly enhanced site safety. At a site with steep slopes, using a terrestrial laser scanner (TLS) allowed surveys to be completed without people entering dangerous high areas. As a result, the risk of worker falls approached zero, and surveying that had previously taken 17 days was shortened to 9 days (about a 50% reduction), achieving both safety and efficiency. During construction, use of ICT-enabled machinery and 3D design data has eliminated the need for staking work around heavy equipment, allowing operators to work with the assurance that no one is nearby, thereby improving both safety awareness and productivity on site.

• Quality and accuracy assurance: Immediate use of digital survey data directly improves construction quality. For example, if detailed as-built point cloud data from drones or smartphones allow real-time grasping of embankment or cutting volumes, excesses and deficiencies can be corrected early to achieve design-compliant as-built conditions. What used to be quantity settlement through post-construction sectional surveys can now be monitored during construction, reducing rework and material loss. Reports also indicate that even young engineers can achieve accuracy comparable to experienced personnel by using 3D designs and survey guidance features, showing that digital technology contributes to skills transfer.

Examples of Advanced Initiatives by Local Governments and Companies

As the effects described above are demonstrated in many places, local governments and construction companies nationwide are competing to implement advanced initiatives. The Ministry of Land, Infrastructure, Transport and Tourism annually recognizes excellent i-Construction case studies with awards such as the “i-Construction Awards,” and there is growing momentum for ICT adoption among local governments and small-to-medium construction companies.

Municipal initiatives: In one local government, contractors were encouraged and supported to use drone surveying and ICT machinery for road improvement projects, achieving shorter schedules and cost reductions. In disaster response, more local governments are adopting drones and 3D surveying to assess damage. For example, at a large-scale landslide site, drone surveying completed what had previously taken several days by manual measurement in a single day, enabling rapid recovery planning. Such government-led ICT utilization has spillover effects to regional construction firms, and a “digitally capable site” is beginning to spread nationwide.

Corporate initiatives: Not only major construction firms but also small and medium-sized contractors are actively adopting advanced technologies. One forward-looking contractor established an internal ICT team to train staff in drone operation and point cloud processing. They distributed tablets to job sites and standardized 3D design data, promoting company-wide cultivation of digital talent and site support. This not only improved performance on ICT-enabled projects but also created a virtuous cycle of being more competitive in bidding as a technology-forward company. Another firm reported that young employees using smartphone surveying and AR were able to manage sites and maintain quality and safety without relying on veteran experience, contributing to workstyle reforms that overturn conventional wisdom.

Across these success stories, a common factor is a “willingness to start early and share know-how across the company.” Organizations that invest in digitalization and training reap dual benefits of improved site productivity and better work environments. In the i-Construction era, technology won’t be mastered by waiting; only when each site worker interacts with new tools, gains experience, and sees the effects firsthand will true transformation occur.

Closing: Easy Surveying DX with Smartphone × RTK

The future envisioned by i-Construction is no longer limited to a few large-scale projects. Surveying solutions using drones and smartphones are evolving daily and have reached a stage where they are accessible to many in terms of cost and technology. The important thing is to “try them on site, even on a small scale.” A sensible first step is to introduce a smartphone surveying tool that can easily achieve high-precision measurement.

For example, LRTK is an innovative solution that allows anyone to achieve centimeter-precision positioning (cm level accuracy (half-inch accuracy)) simply by attaching a compact RTK-GNSS receiver to a smartphone. A single pocket-sized device can become an all-in-one surveying instrument, handling coordinate measurement, 3D point cloud scanning, stakeout work, and even AR overlays of finished images. Acquired data can be shared to the cloud in real time, allowing information measured on site to be immediately shared with the office and other partners, and enabling on-the-spot calculations of distances, areas, and volumes. The app is designed to be intuitive for staff without specialized training, and by making “one survey device per person” a standard item on site, team productivity can be raised across the board. Furthermore, because the introduction cost is lower than that of conventional surveying equipment, LRTK is attractive for small sites and projects with limited budgets.

Surveying is undoubtedly changing now. By leveraging familiar technologies such as drones and smartphones, goals that once seemed out of reach—shorter work times and labor savings—are now within reach. In the i-Construction era, competitiveness depends on how quickly new technologies are adopted and utilized on site. Take this opportunity to experience the benefits of simple surveying with smartphone × RTK. Introducing an easy tool like LRTK can help you take the first step tomorrow toward improved productivity at your site. Embrace cutting-edge surveying technology and let’s shape the future of construction sites together.