The Core of Construction DX! The Smartphone Surveying Revolution Brought by i-Construction

What is i-Construction? Background for DX and the Use of BIM/CIM and ICT

Have you recently heard the terms “construction DX” or “i-Construction”? In the construction industry, a wave of digital transformation (DX) is sweeping through to improve productivity and reform working styles. One of the measures positioned at the center of this movement is i-Construction. This is a reform project proposed by the Ministry of Land, Infrastructure, Transport and Tourism in 2016, aiming to fully introduce ICT (information and communication technology) across all processes on construction sites, and to consistently improve productivity from investigation and design through construction, inspection, and maintenance.

One pillar of i-Construction is the use of BIM/CIM during the investigation and design stages. BIM (Building Information Modeling) / CIM (Construction Information Modeling) are methods that aggregate all information into three-dimensional models for management and utilization in their respective fields of architecture and civil engineering. This shifts traditional document- and drawing-centered workflows to a digital 3D model foundation, making it easier to share information among stakeholders. In the construction phase, the introduction of ICT-equipped construction machinery (machines automatically controlled by GPS and linked sensors) improves heavy equipment operation efficiency and construction accuracy. Standardization of concrete work and leveling construction schedules (smoothing busy and slow seasons) are also pillars of i-Construction, advancing reform across entire sites. Furthermore, by using three-dimensional data for work-as-built management and inspection, on-site labor savings and faster processing are achieved.

Thus, i-Construction is an ambitious initiative to transform the entire construction production system through DX. Behind it are industry challenges such as labor shortages and the aging of skilled technicians. By actively adopting ICT and 3D technologies, the aim is to turn construction sites—traditionally avoided as “3K” (tough, dirty, dangerous)—into workplaces that are easy and attractive for anyone to work in. The Ministry of Land, Infrastructure, Transport and Tourism has adopted the policy “future public works will be connected by three-dimensional data,” and from fiscal 2023 has applied BIM/CIM to all direct-managed projects in principle, promoting an industry-wide shift from 2D to 3D.

Why Surveying Is the Starting Point of i-Construction

In construction projects, surveying (measurement) is the first step. You accurately measure the current terrain and existing structures on site, and then base design and construction plans on that data. In the i-Construction process of “connecting investigation through maintenance with three-dimensional data,” it is indispensable to first record the site as a digital 3D space. Therefore, surveying can be said to be the starting point of construction DX.

Traditional surveying was performed by specialist surveyors using total stations and large GNSS surveying equipment, often requiring multiple people and significant time to measure a single site. However, with the promotion of i-Construction, new technologies such as photogrammetry from drone aerial imagery and point-cloud surveying with 3D laser scanners have emerged, enabling more extensive and higher-precision measurements in shorter timeframes. The three-dimensional survey data obtained in this way can be preserved as a digital copy (digital twin) of the existing terrain, making it easy to measure required dimensions later in the office or to create drawings and models.

Also, if surveying data are digitized into 3D at the initial stage, collaboration with subsequent design and construction processes becomes smooth. For example, designers can create optimal plans on the site’s 3D terrain model, and contractors can import that model into ICT machinery for automated construction. During inspection, obtaining point-cloud data of the finished terrain and comparing it with the design model streamlines as-built inspections. In other words, if surveying remains analog, subsequent ICT construction and BIM/CIM cannot demonstrate their full potential. Digitizing data in the initial survey is a key to overall optimization.

The Surveying Revolution Brought by Smartphones and RTK: Centimeter-Level Measurement in the Palm of Your Hand

In recent years, a groundbreaking evolution has occurred in the field of surveying: surveying DX using smartphones and RTK technology. RTK (Real Time Kinematic) is a technique that combines satellite positioning (GPS, etc.) with correction information from a reference station to perform real-time high-precision positioning with errors of a few centimeters (centimeter-level, half-inch accuracy). Traditionally, survey GNSS receivers and rovers were used together, requiring expensive equipment and specialized knowledge. However, nowadays systems have appeared that let you attach small RTK-capable GNSS antennas to smartphones or link a smartphone’s built-in GPS to RTK network services, creating a revolution where the smartphone itself becomes a high-precision surveying instrument.

Specifically, by attaching a dedicated small GNSS receiver to smart devices like iPhones or iPads and launching a positioning app, one person can walk the site and perform surveys. Since only a pocket-sized device weighing just a few hundred grams is needed, there is no longer a need to carry heavy equipment or to call out a specialist surveying team for measurements. The ease of anyone being able to quickly measure when necessary is transforming on-site work styles.

The benefits of smartphone surveying extend beyond simplicity. Because you can confirm your position on a map in real time while measuring, missed measurements and measurement errors are reduced. Even in complex terrain, measurement points can be visualized on the spot, enabling efficient coverage of points. Measured data are immediately recorded digitally, preventing human errors such as missed entries. Above all, because one person can complete the work, the need for personnel coordination and schedule adjustments is reduced, and surveying can proceed quickly. These new surveying styles are ushering in an era where “anyone can become a surveyor.”

Point Clouds, AR, Automated Reports, Cloud Sharing—A New Dimension of On-Site Data Utilization

Surveying DX with smartphone × RTK does not stop at measuring coordinates. By richly utilizing the digital data acquired on-site, construction management and quality control levels can dramatically improve. Here are the main ways site data can be leveraged through smartphone surveying.

• 3D Point Cloud Measurement: Using LiDAR scanners or high-precision GPS built into smartphones and tablets, you can acquire on-site conditions as point cloud data. For example, if you scan excavated terrain or completed structures, you can later calculate distances, areas, and volumes freely in the office. Point clouds, which can capture a large number of measurement points at once, preserve a “digital copy” of the site including details that were previously overlooked, and are useful for as-built management and future design changes.

• Visualization with AR: By combining AR (augmented reality) technology with high-precision positional information, you can overlay design models or drawing lines onto the real landscape. When viewed through a smartphone screen, a planned finished structure may appear to exist on the spot, or the route of pipes buried in the ground can be viewed in a see-through manner. This enables intuitive verification of discrepancies between design and reality on-site, visually directed instructions to heavy machinery operators, and contributes to improved safety and construction accuracy.

• Automated Report and Drawing Creation: Smartphone surveying apps often include functions to automatically generate prescribed reports and drawings based on the coordinates and elevations of measured points. CSV output of point lists, creation of plan views and longitudinal profiles, and generation of cross-sections required for as-built management—tasks that used to be done manually in the office after surveying—can now be completed with a single button press. Since on-site data can be output directly in formats for electronic delivery, this greatly reduces clerical work and improves accuracy.

• Cloud Sharing and Real-Time Coordination: Survey data can be immediately uploaded and shared in the cloud. It becomes easy to view positioning information and point cloud data sent from the site on an office PC in real time. You can share data with clients and partner companies via URLs, and stakeholders can check results on a browser map without logging in or using special software. This allows the site, the office, and all stakeholders to grasp the latest information in real time, dramatically speeding up decision-making.

By fully utilizing high-precision position and shape data acquired with smartphones, the workflow from surveying to construction management becomes seamless. Sites visualized with point clouds and AR are transforming work that once relied on intuition and experience into data-driven processes.

Benefits That Make Everyone Happy: Municipalities, Surveyors, and Site Managers

The introduction of smartphone surveying brings benefits to many stakeholders in different roles. Here are the advantages from the perspectives of the main users: municipal staff, surveying specialists, and construction site representatives.

• Municipalities (public project owners): For local governments, rapid understanding of current conditions in disaster response and infrastructure inspections is a challenge. With smartphone surveying, a staff member can safely and independently measure the situation at a landslide site after heavy rain, immediately share the data with the main office, and formulate a recovery plan. Even in cases where arranging a surveying contractor used to take time, municipalities can quickly obtain data themselves, speeding initial responses. For routine road maintenance and park management, small teams can efficiently perform on-site surveys and as-built checks, leading to cost savings and faster operations.

• Surveying Companies and Surveyors: Cutting-edge smartphone surveying tools become powerful assets for surveying professionals. While it may sound threatening to hear “anyone can survey,” in practice skilled surveyors using this technology can accomplish far more surveying work with fewer people than before. Time spent transporting and setting up heavy equipment is reduced, allowing a focus on high-value tasks such as survey planning and data analysis. It’s also excellent as a training tool for young technicians—intuitive smartphone operations enable them to learn basic surveying, aiding human resource development. Adopting new technology offers opportunities to improve operational efficiency and service quality, and to differentiate from competitors.

• Site Representatives and Construction Managers: Smartphone surveying is also a strong ally for site representatives overseeing construction sites. Previously, even small surveying tasks required calling a specialist team, causing scheduling and waiting time issues. With smartphone surveying, for example, you can immediately check ground elevations or set out structure positions yourself, making progress management smoother. If questions arise during construction, you can measure the spot on the spot, compare it with design drawings, and instantly decide whether corrective work is needed. By sharing survey results in the cloud as they are obtained, you can collaborate with head office engineers in real time to solve problems. When site representatives themselves master digital technologies, they can operate sites smartly in line with the DX era.

LRTK Smartphone Surveying Implementation Example: The First Step toward Site DX

One concrete solution for smartphone surveying that has attracted attention in recent years is LRTK. LRTK is an innovative system that enables centimeter-level positioning using a smartphone equipped with a small high-precision GNSS antenna and an easy-to-use app. By simply attaching an antenna device that fits in a dedicated case (weighing only a few hundred grams) to a smartphone, surveying work that used to require two people can now be completed by one. Additionally, because costs are significantly lower than conventional surveying equipment, it is easy to deploy multiple units on-site. Operations where each worker carries a smartphone surveying device have become realistic. Acquired positional information and point cloud data are stored in the cloud and can be shared instantly with the office or other companies.

For example, a municipality in the Hokuriku region used LRTK to survey a large-scale landslide site and aided recovery construction planning. Even in mountainous areas outside communication coverage, LRTK compatible with the correction signals (CLAS) provided by the quasi-zenith satellite system Michibiki enabled high-precision positioning, allowing accurate digital recording of on-site conditions even when base stations were down. In this way, portable smartphone surveying tools demonstrate strengths in emergencies.

Of course, in routine civil engineering work, LRTK becomes a “reliable partner” that streamlines daily surveying and as-built management. In earthworks, for example, site supervisors can survey with an LRTK-equipped smartphone, automatically calculate embankment volumes on-site, and share results with their superiors. Processes that previously involved manual calculation and drafting of survey data are now processed in real time, dramatically improving speed and accuracy.

Thus, LRTK smartphone surveying is an excellent introductory example for companies and organizations beginning DX. With just the smartphones on hand and affordable devices, you can start immediately and feel efficiency gains right away. The approach of “digitizing surveying first” is an easy-to-understand first step for DX and is likely to gain on-site understanding. That initial success will encourage investment decisions for the next stages, such as BIM/CIM utilization and ICT construction.

i-Construction, the core of construction DX, is not an initiative only for special companies. Even small sites and local governments can practice DX through smartphone surveying. Why not begin building efficient and resilient sites by realizing end-to-end digitalization from surveying to construction with the latest technologies? The time has come to open the door to DX for your site, starting with the smartphone surveying revolution. Now is the time to take that first step and forge the future of construction sites with the smartphone surveying revolution.