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

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

You may have recently come across the terms “construction DX” or “i-Construction.” In the construction industry, a wave of digital transformation (DX) is sweeping through in pursuit of productivity improvements and work-style reform. One of the central initiatives in this movement is i-Construction. Proposed by the Ministry of Land, Infrastructure, Transport and Tourism in 2016, this reform project aims to fully introduce ICT (information and communication technology) into all processes at construction sites, with the goal of raising productivity consistently from surveying and design through construction, inspection, and maintenance.

One pillar of i-Construction is the use of BIM/CIM during the surveying and design phases. BIM (Building Information Modeling) / CIM (Construction Information Modeling) are methods for consolidating and managing all information in 3D models in the fields of architecture and civil engineering. This shifts traditional paper- and drawing-centered workflows onto 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 sensors) improves operation efficiency and construction accuracy. Standardization of concrete works and leveling of construction schedules (smoothing peaks and troughs in busy and quiet seasons) are also pillars of i-Construction, driving overall reform at sites. Furthermore, by using 3D data for quality control and inspections, on-site work can be streamlined and accelerated.

In this way, i-Construction is an ambitious effort to transform the entire construction production system through DX. Behind it lie 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—which have been shunned as the “3K” (tough, dirty, dangerous)—into workplaces that are attractive and easy for anyone to work in. The Ministry of Land, Infrastructure, Transport and Tourism has set the policy that “future public works will be connected by 3D data,” and from fiscal 2023 it has applied BIM/CIM to virtually all directly managed projects, accelerating the 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. Accurate measurements of the site’s terrain and existing structures form the basis for design and construction planning. In the i-Construction vision of “connecting surveying to maintenance with 3D data,” it is essential to first record the site as a digital 3D space. Therefore, surveying can readily be called the starting point of construction DX.

Traditional surveying was performed by specialized surveyors using total stations and large GNSS surveying devices, requiring several people and considerable time to measure a single site. But with the promotion of i-Construction, new technologies such as photogrammetry from drone aerial imagery and point-cloud surveying using 3D laser scanners have appeared, enabling faster, wider-area, and higher-accuracy measurements. The 3D surveying data obtained can be stored as a digital copy (digital twin) of the existing terrain, making it easy later in the office to measure dimensions or create drawings and models.

If surveying data are digitized into 3D early on, collaboration with subsequent design and construction processes becomes smoother. For example, designers can plan optimally on a 3D terrain model of the site, and contractors can import that model into ICT-equipped machines for automated construction. In the inspection phase, acquiring point-cloud data of the completed terrain and comparing it with the design model streamlines as-built inspections. Put another way, if surveying remains analog, ICT construction and BIM/CIM cannot deliver their full value. Digitizing data in the initial surveying stage is the key to overall optimization.

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

Recently, a groundbreaking evolution has occurred in the field of surveying: the surveying DX that uses smartphones together with RTK technology. RTK (Real Time Kinematic) is a technique that combines satellite positioning (GPS, etc.) with correction information from a reference station to achieve real-time positioning with errors on the order of several centimeters. Traditionally, surveying required GNSS receivers and roving units used as a set, expensive equipment, and specialized knowledge. However, small RTK-capable GNSS antennas that attach to smartphones and systems that link a phone’s built-in GPS to RTK network services have now emerged, sparking a revolution in which a 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 surveying app, one person can walk a site and carry out measurements. Because the device can be a pocket-sized unit weighing only a few hundred grams, there is no longer a need to carry heavy equipment or call in a specialized survey team just for measurements. The ease with which anyone can quickly measure when needed is transforming on-site work styles.

The advantages of smartphone surveying go beyond convenience. Because you can confirm your position on a map in real time while measuring, omissions and measurement errors are reduced. Complex terrain can be visualized on the spot, allowing efficient coverage of measurement points. Measured data are immediately recorded digitally, preventing human errors such as missed entries. Above all, because a single person can complete the task, personnel arrangements and scheduling become simpler, enabling rapid surveying. These new surveying styles are opening an era in which “anyone can become a surveyor.”

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

The surveying DX enabled by smartphone × RTK does more than just record positional coordinates. By richly exploiting the digital data collected on site, the level of construction management and quality control can be dramatically raised. Here are the main ways smartphone surveying enables data utilization.

• 3D point-cloud measurement: By using LiDAR scanners built into smartphones and tablets or high-precision GPS, site conditions can be captured as point-cloud data. For example, scanning excavated terrain or completed structures allows you to later measure distances, areas, and volumes freely in the office. Because point clouds capture a large number of measurement points at once, including details that were previously overlooked, they create a “digital copy” of the site useful for as-built management and future design changes.

• Visualization with AR: Combining AR (augmented reality) technology with high-precision positioning allows design models or drawing lines to be overlaid on the real landscape. Through a smartphone screen, it can appear as if the planned structure already exists on site, or you can see the route of buried pipes as if peering through the ground. This enables intuitive on-site checks of discrepancies between design and current conditions and provides visual guidance to machine operators, improving safety and construction accuracy.

• Automated report and drawing creation: Smartphone surveying apps often include functions to automatically generate required reports and drawings from measured coordinates and elevations. Tasks that used to be handled manually in the office—such as exporting survey point lists as CSV files, creating plan and profile drawings, and producing cross-sections for as-built management—can now be completed with a single tap. Because the on-site data can be output in formats ready for electronic delivery, this greatly reduces administrative workload and improves accuracy.

• Cloud sharing and real-time coordination: Measured data can be uploaded to the cloud immediately and shared. It becomes easy, for instance, to check positioning information and point-cloud data sent from the field on an office PC located elsewhere. Data can be shared with clients and subcontractors via URLs, allowing results to be reviewed on a web map without logins or special software. This enables the site, the office, and all stakeholders to grasp the latest information in real time, significantly speeding decision-making.

By fully leveraging high-precision positional and geometric data obtained by smartphones, workflows from surveying to construction management become seamlessly connected. Sites “visualized” by point clouds and AR are transforming work that once relied on intuition and experience into data-driven processes.

Benefits for Everyone: Municipalities, Surveyors, and Site Managers

The introduction of smartphone surveying brings benefits to various stakeholders with different roles. Below are the advantages from the perspectives of the main users: municipal staff, surveying professionals, and site managers.

• Municipalities (public works clients): For local governments, quickly grasping site conditions is crucial in disaster response and infrastructure inspections. With smartphone surveying, staff can safely and independently measure conditions at a landslide site after heavy rain and immediately share the data with the central office to draw up recovery plans. Even in cases where arranging a surveying contractor used to take time, quick in-house data acquisition accelerates the initial response. Routine road maintenance and park management also benefit: fewer people can efficiently conduct as-built checks and condition surveys, reducing costs and speeding up operations.

• Surveying companies and surveyors: Cutting-edge smartphone surveying tools can become powerful assets even for surveying professionals. While the idea that “anyone can survey” might seem threatening at first glance, when experienced surveyors use these technologies they can handle far more surveying tasks with fewer people. Time spent transporting and setting up heavy equipment can be reduced, freeing them to focus on higher-value work such as survey planning and data analysis. These tools are also excellent for training young technicians—intuitive smartphone operations make it easier to learn basic surveying—helping in workforce development. Adopting new technologies can improve operational efficiency and service quality and provide opportunities to differentiate from competitors.

• Site agents and construction managers: For site agents responsible for construction sites, smartphone surveying is a dependable ally. Previously, even minor surveying tasks required engaging a specialist survey team, creating scheduling delays and waiting time. With smartphone surveying, site staff can immediately check ground elevations or layout structure positions themselves, smoothing progress control. If an issue arises during construction, they can measure the point on the spot, compare it with the design drawing, and quickly decide whether remedial work is necessary. By sharing surveying results to the cloud as they are obtained, headquarters technicians can collaborate in real time to resolve problems. When site agents themselves master digital tools, they can run smarter sites suited to the DX era.

Example of Smartphone Surveying with LRTK: The First Step Toward On-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 by attaching a small high-precision GNSS antenna to a smartphone and operating it with an app anyone can use. Simply attaching an antenna device that fits in a dedicated case (weighing only a few hundred grams) to a smartphone allows surveying work that used to require two people to be completed by one person. Moreover, because the price is far lower than traditional surveying equipment, it is easy to deploy multiple units on site. It has become realistic for each worker to carry a smartphone surveying device. The acquired positioning information and point-cloud data are stored in the cloud and can be shared instantly with the office and other companies.

For example, a municipality in the Hokuriku region used LRTK to survey a large-scale landslide site and helped plan recovery work. In mountainous areas with no mobile coverage, LRTK compatible with correction signals provided by the Quasi-Zenith Satellite System “Michibiki” (CLAS) can still achieve high-precision positioning, allowing accurate digital recording of site conditions even when base stations are down. In emergencies like these, small, portable smartphone surveying tools demonstrate significant strengths.

Of course, in everyday civil engineering work, LRTK is also a reliable companion that streamlines routine surveying and as-built management. For instance, at an earthworks project, a site supervisor can use an LRTK-equipped smartphone to survey and have the embankment volume calculated automatically on the spot, then share the results with superiors. Processes that once required manual calculation and drafting in the office are now processed in real time, dramatically improving both speed and accuracy.

Thus, smartphone surveying using LRTK is an excellent introductory example for companies and organizations beginning their DX journey. With a personal smartphone and affordable equipment, you can start immediately and experience operational efficiency gains right after deployment. The approach of “starting DX by digitizing surveying first” is an easy-to-understand first step that tends to gain acceptance on-site. That initial success helps justify investments in subsequent stages such as further BIM/CIM utilization and ICT-driven construction.

i-Construction, the core of construction DX, is not the exclusive domain of special companies. Even small sites and local governments can practice DX through smartphone surveying. By leveraging the latest technologies to achieve consistent digitization from surveying through construction, you can begin building efficient and resilient sites. Starting with the smartphone surveying revolution, it’s time for your site to open the door to DX. Now is the moment to take that first step and use the smartphone surveying revolution to shape the future of construction sites.