Surveying and Layout Transformed by ICT–Construction Machinery Integration: The Forefront of Automated Construction Using MC/MG

In recent years, methods of setting-out (sokusetsu) at construction sites have been changing significantly. Setting-out refers to surveying work that accurately transfers the position and elevation of structures shown in design drawings to the field, i.e., the location-marking work called "staking and batter-boarding". Traditionally, surveys using a Total Station (TS) combined with height markings on stakes were carried out manually by a surveyor and assistants. However, the spread of ICT construction machines (construction machinery equipped with information and communication technology) has led to the adoption on-site of new setting-out methods integrated with digital data. This article explains the latest trends in automated construction using ICT construction machines' machine control (MC) and machine guidance (MG), and the accompanying transformation of setting-out tasks. Using major construction machines such as backhoes (hydraulic excavators), bulldozers, and graders as examples, the article comprehensively introduces setting-out methods under automated construction using three-dimensional design data, as-built management, alignment with reference points, and on-site operational workflows. It also clarifies differences from conventional TS- and batter-board setting-out, lays out challenges during implementation (initial setup, coordinate accuracy, operator training), and examines key points for building the setting-out skills and organizational structures required in the era of ICT construction. At the end of the article, it also touches on the simple RTK setting-out solution LRTK, which combines a smartphone and a compact GNSS receiver, and introduces its potential as a new on-site tool that can coexist with ICT construction machines.

The Evolution of Surveying and Layout Brought About by ICT Construction Machinery and Automated Construction

ICT construction machinery refers to construction equipment equipped with GPS, GNSS, total stations, angle sensors, and other devices that utilizes digital design data to improve work efficiency and accuracy. They are being introduced as part of "i-Construction," promoted by the Ministry of Land, Infrastructure, Transport and Tourism, and are mainly used on earthwork sites where hydraulic excavators, bulldozers, motor graders, and the like equipped with 3D machine guidance (MG) and 3D machine control (MC) functions are active. ICT construction machinery replaces construction that had previously depended on operator skill and visual judgment with data-driven automatic and semi-automatic control, enabling uniform, high-precision work. As a result, significant efficiency improvements in surveying and layout work have become possible. Traditionally, survey teams went to sites to install numerous reference stakes and batter boards, and operators relied on them to carry out work, but with ICT construction machinery, 3D design data and real-time positioning allow the machines themselves to constantly know the position and elevation of the design surface, making construction that does not depend on batter boards possible.

*An example of a backhoe equipped with 3D machine guidance. The onboard monitor displays deviations from the design surface in real time, eliminating the previously necessary installation and verification work for slope stakes. There are fewer occasions for workers to place stakes around the heavy equipment or for operators to get out of the machine to confirm accuracy, greatly improving safety and efficiency.*

The ICT construction machinery's MG (Machine Guidance) function is a system that displays on the operator's monitor the deviation between the machine's current position and the design surface, and provides the operator with guidance information. It is installed on bulldozers and backhoes, compares preloaded 3D design data with position information from GNSS or an automatic-tracking total station (TS), and notifies the operator visually and audibly of information such as "how many centimeters (inches) remain to be excavated" and "how far off the design grade it is." MG serves purely as a navigation aid, and the actual steering and lever operations are performed by the operator. Meanwhile, the MC (Machine Control) function is an extension of MG and is a system that automatically controls the machine's operations based on position information and design data. For example, in a bulldozer it instantaneously calculates the design elevation and grade corresponding to the blade position determined by GNSS, and automatically adjusts the blade's vertical position and tilt angle via hydraulic control. On backhoes as well, automatic control allows the bucket's height and angle to continuously follow the design surface while the operator simply operates the arm. MC is, so to speak, autopilot construction, and a major advantage is that it can achieve high-precision finishing regardless of the operator's skill.

With the introduction of such ICT-equipped construction machinery, surveying and layout work is shifting from physical "setting-out" tasks in the field to management tasks on digital data. Because operators can work while cross-checking the machine's current position and the design surface on a monitor, they no longer need to rely solely on experience and intuition. As a result, this has led to reductions in rework (corrections for over-excavation and overfilling) and shorter construction schedules. For surveyors as well, the burden of installing and maintaining stakes and string lines has been reduced, and their role has shifted to focusing on digital tasks such as preparing 3D data and verifying as-built data.

Digital surveying methods integrated with 3D design data

3D design data is the core of ICT construction, and surveying and measurement work also begin with creating this data. First, point cloud data of the existing terrain is acquired using drone aerial photography, terrestrial laser scanners, GNSS surveys, etc., and the alignment and elevation information from the design drawings are combined to create a 3D model of the construction target (in TIN or LandXML formats, etc.). The resulting digital design surface data is then imported into on-board computers or control boxes mounted on ICT construction machines. If the same data is transmitted to a total station, it can also be used for TS-based as-built measurement and tracking construction. In other words, everyone on site shares unified 3D design information and conducts construction and surveying based on that standard.

After bringing ICT construction machinery onto the site, first perform initial setup (calibration). Specifically, install a GNSS base station (reference station) on a known local control point (a point whose coordinates are known). This base station calculates in real time the difference between the positioning information obtained from satellites and the known coordinates, and transmits the correction data wirelessly to the machine’s rover, enabling centimeter-level accuracy (half-inch accuracy) positioning across the entire site. Also, depending on the site, the base station may be omitted by using regional electronic reference point networks or commercial RTK correction services. In any case, it is important to match the site's coordinate system (such as the plane rectangular coordinate system) with the coordinate system of the design data. As needed, perform localization (survey coordinate transformation) using known points and benchmarks to align GNSS positioning values with the site's reference elevation. If this coordinate alignment is not done correctly, even if the machine is automated, discrepancies from the design will occur, so careful surveying work is required during the initial setup phase.

Once reference point setting and 3D data input are complete, it's the start of automated construction with ICT construction equipment. For an excavator, angle sensors mounted on the boom and arm continuously calculate the spatial position of the bucket tip and determine its coordinates using a GNSS antenna and correction information. The operator advances excavation while watching the difference between the current height of the bucket tip displayed on the monitor and the design surface height, making fine adjustments as necessary (in the case of MG). If an MC function is available, enabling the selected automatic control mode semi-automatically controls the movements of the bucket or blade, allowing the finished surface to be graded exactly as designed.

In this digital surveying and layout, the intermediate verification tasks that were traditionally essential have also been streamlined. In the past, there were time-consuming steps such as taking levels during excavation to check elevations or the operator dismounting to check the batter boards. With ICT-equipped construction machinery, real-time inspection and measurement during construction is possible. In other words, because you can continuously compare the current as-built condition with the design data while working, you can immediately notice mistakes during construction and correct course. For example, a machine-control (MC) bulldozer can automatically grade almost exactly to the design surface, and the operator can also monitor the finished state on a display. As a result, quality control aimed at "zero rework" is becoming less of a dream.

Digitalization of As-built Management and Quality Verification

As with surveying and setting-out, as-built control (shape verification after construction completion) in ICT construction is also being digitized. Traditionally, surveying teams would once again mobilize to measure key elevations and positions on completed structures and ground with TS and levels, and perform quality inspections by comparing them with the design drawings. On sites that utilize ICT, cases of rapidly acquiring as-built data using 3D scanners, drone photogrammetry, and even sensors mounted on heavy machinery are increasing. For example, for a slope shaped by a backhoe MC, the machine’s construction history data (the set of coordinates the bucket passed through) can be stored and used directly as the as-built result. Also, by flying a drone over the site after construction to acquire a point cloud of several million points and then performing a color-coded display of differences from the design 3D model, such advanced inspections can be done instantly. This allows any areas that require rework to be identified on the spot, enabling operations that minimize corrections.

Results of as-built management are increasingly being shared instantly on the cloud with stakeholders. If point clouds and survey data collected on site are uploaded from a tablet device, they can be checked and verified immediately in the office. This eliminates waiting time for data to travel between the field and the office, and speeds up the preparation of inspection reports. Moreover, such 3D as-built data becomes a valuable record that can assist with future maintenance and the calculation of completed quantities. In ICT-enabled construction, digital data are consistently linked from surveying through design, construction, and inspection, so by accumulating and analyzing these data it is also possible to achieve improvement of the entire construction process.

Differences from conventional TS and batter-board layout surveying

The approach and the skills required differ greatly between traditional surveying and setting-out work and construction using ICT. First, regarding the installation of batter boards, traditionally batter boards that serve as height and position references at regular intervals were set up on roadbeds and slopes in road works, and operators adjusted slopes and thicknesses using them as markers. The finished accuracy varied depending on the operator’s skill, and because surveyors had to enter heavy equipment operating areas to drive stakes and string lines, there were also safety risks. On the other hand, as mentioned above, ICT-equipped construction machinery can greatly reduce the use of batter boards. The monitor constantly displays the difference between the current height and the design height, and provides necessary guidance, freeing operators from relying on guesswork while looking at stakes. As a result, stationing workers around heavy equipment is no longer necessary, which also helps prevent near-miss incidents between surveyors and machinery. In actual sites, a minimal number of stakes may be left at key starting points or for verification, but compared to traditional methods, manual surveying and setting-out have been dramatically reduced.

Also, there is a significant difference in staffing and work time. Traditionally, the benchmark-setting work that used to be done by a surveying team of 2–3 people over half a day to several days can be completed at ICT-enabled sites with only prior data preparation and initial setup. For example, wide-area topographic surveys can be finished in a short time with one drone and one operator, and because ICT construction machines advance construction based on that data, small teams can work in parallel. This makes it easier to establish a production system that meets deadlines even amid labor shortages. In terms of quality, variation due to craftsmanship has been a challenge, but data integration provides the fairness that the same results can be achieved regardless of who operates. For example, whether a veteran or a young worker, with the support of ICT construction machines you can expect uniform finishing quality. Overall, the major advantages of surveying and setting out using ICT construction are "ensuring accuracy without dependence on people" and "labor savings and improved safety".

Challenges and Countermeasures When Introducing ICT Construction Machinery

While ICT construction is convenient, there are several challenges to overcome in the initial stages of introduction. First is the difficulty of initial setup. System calibration using GNSS equipment and TS requires specialized knowledge, and for each site the optimal installation and verification of the signal reception environment must be performed. In particular, in Japan’s mountainous areas and urban districts there are locations where satellite reception is unstable, so careful consideration of base station placement and TS deployment planning is required. Also, proficiency is necessary for the attachment and removal of sensors on heavy machinery. Currently, mounting brackets differ by model and some older machines cannot be retrofitted, so it is necessary to proceed while confirming the modification costs and feasibility for existing machines.

Next is the issue of coordinate accuracy and data compatibility. Different ICT construction equipment manufacturers may use different data formats and reference systems, and compatibility problems can occur when using machines or software from different manufacturers together. When converting design data supplied by the client into your company's heavy equipment format, you must take utmost care to ensure there are no differences in interpretation of the drawings or misalignments of coordinate systems. If a control point is set incorrectly or a coordinate conversion error occurs, it can affect the as-built condition of the entire site, so a robust data manager review system is important.

And training of operators and technicians is also a major theme. Even high-performance ICT construction machinery will be a wasted asset if people cannot use it correctly. In particular, for veteran operators accustomed to traditional methods, the sensation of operating while watching a monitor or entrusting control to automatic systems may feel unfamiliar at first. On site, an education period until everyone understands and accepts the benefits of ICT construction is necessary. It is important to actively introduce operation courses from manufacturers and training organizations and training on data utilization, and to foster a culture of sharing know-how within the site. Fortunately, national and local governments are also offering technical training and personnel support measures related to i-Construction, so it is advisable to advance in-house human resource development while utilizing those programs.

Finally, there is an issue regarding costs. The initial investment for ICT-equipped construction machinery, surveying drones, 3D design software, and the like is by no means cheap. For small and medium-sized construction businesses, introducing the full set all at once can be a heavy burden, so considering leasing, renting, or phased implementation is a viable option. A realistic approach is to first pilot ICT construction on small sites or specific processes, and expand capital investment while assessing the effects and challenges. Also, government subsidies and grants are becoming more available, and in some cases, if certain requirements are met, part of the ICT equipment installation costs may be subsidized. In the long term, the cost benefits from reduced labor costs and reduced rework are likely to exceed the initial investment, and it is important to estimate ROI (return on investment) to make management decisions.

Surveying and Setting-Out Skills and Organizational Structure Required in the ICT Construction Era

To smoothly advance ICT-based construction, a different set of skills and organizational structures than before is required. First, surveying technicians must have skills for handling digital data. Specifically, a broad range of ICT knowledge is required, such as knowledge of 3D surveying (drone surveying and 3D scanning), model-creation skills in BIM/CIM software, and understanding of GNSS positioning principles and coordinate system transformations. Since these abilities cannot be acquired overnight, companies should systematically develop young engineers internally and, when necessary, consider recruiting specialized personnel from outside. It is ideal to establish a position that could be called on-site DX personnel, who can bridge site supervisors, surveyors, and operators and take responsibility for 3D data management and equipment setup.

Operators also need digital literacy. Nowadays it is common for tablets and monitors to be installed in the cabs of heavy machinery, so basic computer skills and an understanding of on-screen menus are essential. However, with increasingly intuitive UI designs, many younger workers from the smartphone generation seem to accept them without resistance. As a company, it is important to undertake initiatives to instill the benefits and operation methods of ICT construction in all site personnel. Creating an atmosphere that embraces new technologies as part of site culture is required, for example by sharing success stories in morning meetings and internal training, and by providing one-on-one instruction to members who feel uncertain about operating them.

A key point in establishing the system is centralized management and sharing of data. In ICT construction, everything from survey data to construction history and as-built data is retained as digital information. Manage these in the cloud or on dedicated servers, and create a system that allows all stakeholders—design staff, site representatives, heavy equipment operators, inspectors, and others—to access them as needed. By thoroughly enforcing data sharing, you can prevent miscommunications such as “only the site understands it and the designer is not aware,” and achieve advanced quality control across the entire team.

Latest Trends and Future Outlook for Automated Construction

The field of ICT construction is advancing rapidly. Currently, a major trend attracting attention is the integration with AI, IoT, and 5G communications. AI (artificial intelligence) is expected to be used for automatic analysis of construction data, automation of as-built inspections, and even for future autonomous operation of construction machinery (unmanned construction). For example, research is progressing in which AI analyzes real-time sensor data to propose optimal construction patterns to operators or to coordinate control of multiple pieces of heavy equipment. In addition, teleoperation, which involves operating construction machinery from remote locations, is beginning to be put into practical use, and the deployment of high-speed, low-latency 5G networks has made safe and smooth remote construction possible. If these technologies become widespread, new construction styles such as unmanned construction, allowing people to avoid entering dangerous sites, and skill sharing, where experienced workers support multiple sites remotely, could become common.

On the other hand, looking at Japan’s construction industry as a whole, ICT-enabled construction is still mainly being adopted by major general contractors and public works, and its penetration into small and medium-sized businesses is still at an early stage. Going forward, strengthening support for small and medium-sized businesses will be key. For example, expectations include establishing technical support centers by national and local governments, developing low-cost and simple ICT construction solutions (easy-to-install kits for small machines and smartphone apps), and enhancing training programs by industry associations. The government has already put forward measures to promote i-Construction and support the introduction of ICT to small sites as productivity-improvement measures in response to the “2024 overtime regulations (the 2024 problem).” For example, the expansion of subsidy programs and trial-lending systems for local contractors are accelerating efforts to broaden the base.

Furthermore, overseas construction-tech examples are also instructive. In Europe and North America, construction-equipment manufacturers are collaborating on data standardization, and platforms are being developed so that 3D data can be used seamlessly across different machine types. In Japan as well, it will be necessary for the public and private sectors to jointly establish open standard specifications and, by enhancing interoperability across both software and hardware, create an environment that makes it easier for any company to enter ICT construction. As the technology matures and prices fall, and as subscription-based services and leasing become more widespread and lower adoption barriers, an era will arrive in which even small and medium-sized enterprises can use ICT construction in everyday practice.

Simple RTK Surveying with Smartphones and Compact GNSS: Utilizing LRTK

While large-scale efficiency improvements through ICT construction machinery are progressing, simple surveying tools that leverage smartphones have also emerged on job sites. A representative example is RTK positioning using a smartphone + compact GNSS receiver, and Refixia's "LRTK" is a pioneering product in this area.

The LRTK is a device that, by simply attaching a dedicated ultra-compact RTK-GNSS receiver to a smartphone, transforms the phone into a centimeter-level surveying instrument. Weighing just about 165 g and pocket-sized, it can reduce a smartphone's positioning error in standalone positioning from several meters (several ft) to a few centimeters (a few in) in real time. This is achieved by a technology called RTK (Real Time Kinematic), which applies correction information from reference stations received via the smartphone to the compact receiver, enabling high-precision positioning.

*An example of a compact RTK-GNSS receiver, "LRTK", that attaches to a smartphone. The smartphone itself becomes a high-precision surveying instrument, allowing a single person to easily perform on-site positioning and as-built measurements. Its pocket-sized compactness and the ability to take it out and use it for surveying whenever needed are popular with field workers.*

Using this smartphone RTK positioning, rapid one-person surveying and setting-out work is possible. For example, tasks such as laying out batter-board stake positions, which were traditionally done by two-person teams, can be performed by a site supervisor who goes to the point to be measured with a smartphone in hand, confirms the exact coordinates on the spot, and marks them. With LRTK, aligning coordinates to reference points (conversion to the plane rectangular coordinate system) and adjusting height references can also be done easily within the smartphone app, and it handles everything in an all-in-one manner—from managing point names to recording notes. Measurement data can be shared to the cloud in real time, so you can immediately reflect measurements in office drawings and verify them with remote team members.

This kind of simple RTK surveying tool plays a complementary role even at sites where ICT construction machinery is active. When finishing details by hand that are outside the automatic construction range of heavy machinery (such as backfilling around structures or in narrow areas), you can quickly check heights with a smartphone, or record additional survey points on the spot when attending as-built inspections, enabling agile surveying. Above all, by using the familiar device of a smartphone, the introduction cost is low, and the LRTK devices themselves are very affordable compared with traditional expensive surveying instruments, typically costing a few hundred thousand yen. It has become realistic even for small and medium enterprises to operate with site staff each carrying one smartphone surveying device per person. This helps ensure that measurements are digitized throughout the site and that anyone can easily manage accuracy.

ICT-enabled construction machinery and smartphone RTK are not opposing technologies but a complementary combination that maximizes jobsite efficiency. Leave the bulk earthworks to MC-equipped construction machinery and use a nimble smartphone for fine finishing checks and additional surveys to achieve both labor savings and improved accuracy. Going forward, increasingly user-friendly digital surveying and layout tools will appear, and an era will come when anyone on the jobsite can take on surveying tasks. Surveying and layout professionals should actively adopt these new technologies while honing the skill of "being able to speak about the jobsite with data".

Please provide the Japanese text you would like me to translate into English.

Conclusion: Surveying and layout is a crucial foundational task on construction sites, and its form has been dramatically transformed by the introduction of ICT-enabled construction machinery. Automation of construction through data integration is beginning to demonstrate effective solutions to challenges such as labor shortages and quality variability. At the same time, there is a need to develop personnel and build organizations capable of mastering new technologies. By leveraging the latest smartphone RTK tools and the like, let us aim for sites where anyone can efficiently perform high-precision surveying and layout. On the front lines of ICT construction, the role played by surveying professionals will only become more important going forward. With next-generation surveying capabilities that combine digital and on-site skills, let us drive the productivity revolution at construction sites.