The Ministry of Land, Infrastructure, Transport and Tourism Is Promoting It Too! What Is the Latest BIM/CIM-Compatible Solution LRTK?

BIM/CIM is now an unavoidable keyword in the construction and infrastructure industry. The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) is strongly promoting the introduction of BIM/CIM as a pillar of productivity improvement on construction sites and digital transformation (DX) in the infrastructure sector. From fiscal 2023, the principle of applying BIM/CIM to directly managed projects began, and unless there are special circumstances, the use of 3D models in all design and construction work is now the default. Furthermore, BIM/CIM is scheduled to become fully mandatory for public works by 2027, and it is already being introduced in projects worth roughly JPY 2.5 trillion annually. The construction industry is at a major turning point, and full-scale BIM/CIM adoption is imperative.

Amid this situation, a cutting-edge solution called "LRTK" (pronounced L-R-T-K) is attracting attention. As a high-precision positioning technology that links BIM/CIM with fieldwork, it is a groundbreaking tool that aligns with MLIT-promoted infrastructure DX. This article explains BIM/CIM basics, its benefits, use cases, challenges, and the latest technology trends, and then provides a detailed introduction to the principles and features of the new BIM/CIM-compatible solution LRTK and its contribution to BIM/CIM adoption. Finally, through a simple surveying experience using LRTK, we offer a perspective intended to make readers feel "I want to try this" or "I want to consider adopting it."

Definition of BIM/CIM and the Background of Its Adoption (MLIT Policy and Infrastructure DX)

What Is BIM/CIM? Its Definition and Purpose

BIM/CIM stands for Building/Construction Information Modeling, Management, and refers to the method of digitizing and utilizing information handled in construction projects, both in building and civil engineering. Concretely, it centralizes and shares information across stages of construction projects—such as survey, measurement, design, construction, and maintenance—using 3D models and related documents to improve the efficiency of overall business processes. BIM originally developed in the architectural field as Building Information Modeling, which creates 3D models of buildings and uses integrated data of attribute information (material, dimensions, cost, etc.). CIM extends that concept to the civil field, applying it to the entire life cycle of social infrastructure from planning and design to construction and maintenance. In Japan, BIM and civil engineering are promoted together as “BIM/CIM,” and BIM/CIM models include the following elements.

• 3D models: Data that represents shapes, dimensions, and positional relationships of structures in three-dimensional space. Used for visualizing exteriors and internal structures, clash detection, and simulations.

• Attribute information: Detailed information linked to each component in a 3D model (material, strength, price, construction dates, etc.). Used for performance analysis, cost estimation, and construction and maintenance planning.

• Reference information: External documents associated with 3D models, such as drawings, photos, point cloud survey data, and reports. It is important to appropriately use traditional 2D drawings and reports alongside 3D models.

By introducing BIM/CIM, these data can be centrally utilized and shared to improve productivity for both clients (owners) and contractors. Information that was difficult to grasp from paper drawings can be visualized with digital models, deepening common understanding among stakeholders. The result is a reduction in rework, improved quality, and enhanced safety. Indeed, BIM/CIM can be said to be the foundation for realizing digital twins of the construction field (technology that reproduces the physical space in cyberspace). For example, in the reconstruction of Shuri Castle, a “Shuri Castle digital twin” was built using BIM/CIM and used for information sharing among construction stakeholders and visitors.

MLIT-Promoted Infrastructure DX and the Background of BIM/CIM Adoption

Japan’s construction industry has long faced issues such as a declining working-age population, aging skilled workers, and labor shortages. To address these challenges, MLIT launched the i-Construction initiative in 2016 to improve site productivity through ICT utilization and construction method improvements. Since 2020, the DX of the infrastructure sector has accelerated, promoting the introduction of new technologies from the viewpoint of utilizing 3D data and optimizing the entire construction production process.

In this trend, BIM/CIM has been positioned as a core technology for infrastructure DX, and MLIT decided on its full-scale adoption in MLIT-managed civil engineering works and tasks. As noted above, from April 2023, the principle of applying BIM/CIM began for all MLIT-directly managed projects and tasks. This policy—“use BIM/CIM as a principle unless there are special circumstances”—covers design tasks (planning and detailed design), civil engineering works (rivers, dams, roads, etc.), and related surveys and geological investigations. BIM/CIM, which had previously been experimental, is becoming a standard work method.

In April 2024, MLIT launched the next step called “i-Construction 2.0.” i-Construction 2.0 aims for “productive construction sites where a small number of workers can work safely and comfortably” and incorporates remote construction, automation, AI and robotics, among other measures. From 2025 onward, the Infrastructure DX Promotion Committee will continue to discuss expanding ICT-based construction, introducing new technologies, optimizing entire processes, and standardizing data linkage, and relevant standards and guidelines will be developed. In short, the government is accelerating the digital transformation of the construction industry, with BIM/CIM as a central theme.

Given this background, it is not an exaggeration to say that companies that do not adopt BIM/CIM may be excluded from public works. On the other hand, companies that adopted BIM/CIM early have already achieved significant results—reports indicate design errors reduced by about 85% and cost reductions of 5–12%, with surveys suggesting initial investment can be recovered within 3–5 years. MLIT and industry associations’ research is beginning to show quantitative benefits of BIM/CIM adoption, indicating that it is not a mere trend but a high-return investment strategy.

Benefits of Introducing BIM/CIM (Productivity Improvement, Use of 3D Data, Effects on Maintenance and Management)

Introducing BIM/CIM brings a variety of benefits across every phase of a construction project. Below we look at effects in the design, construction, and maintenance stages.

• Design stage: 3D models dramatically improve design accuracy and visualization. Even complex structures can be intuitively understood, and automating clash detection greatly reduces human error. Using attribute information enables cost and schedule simulations, improving budgeting and schedule management accuracy. Furthermore, passing design data directly to construction and maintenance stages preserves information consistency and contributes to improved quality and safety. For example, in bridge design, BIM/CIM adoption reportedly reduced design errors by about 85% and made structural safety verification more efficient.

• Construction stage: Using BIM/CIM models on site enables advanced and efficient construction management. When all construction stakeholders share the 3D model, mismatches in design intent and communication errors decrease, leading to improved quality. Recording progress and inspection results as attribute information in the model allows real-time understanding of progress and quality control. After construction, the model itself can serve as an electronic deliverable or as-built documentation, smoothing final inspections and handovers. In one tunnel project, using BIM/CIM models along with 4D (schedule) simulation and VR/AR technology optimized construction planning and shortened the installation period for precast members by 40% compared with original plans. Pre-construction reviews using models eliminated waste in schedules and reduced safety risks even within constrained spaces.

• Maintenance and management stage: BIM/CIM models remain valuable after completion. Accumulating inspection results and repair histories as attribute data on the completed 3D model builds a digital twin of the structure. This makes it easier to predict deterioration and develop repair plans based on past condition histories during inspections. Maintenance tasks that used to require flipping through ledgers and drawings can be streamlined by centralized model-based management. For example, in bridge maintenance, marking damage locations on a 3D model and recording coordinates, photos, and inspection dates allows precise checks at the same location during future periodic inspections, aiding prioritization and budgeting for repairs. BIM/CIM can thus reduce life-cycle costs of infrastructure assets and enable preventive maintenance.

As shown above, BIM/CIM brings major benefits in three areas: improved design quality, increased construction productivity, and more efficient maintenance and management. MLIT is focusing on these effects, expecting that BIM/CIM dissemination will lead to future workstyle reforms on construction sites, improved cost structures, and enhanced safety. While introducing BIM/CIM is not easy, the benefits are so substantial that industry-wide efforts are warranted.

• Maintenance and management stage: BIM/CIM models remain valuable after completion. Accumulating inspection results and repair histories as attribute data on the completed 3D model builds a digital twin of the structure. This makes it easier to predict deterioration and develop repair plans based on past condition histories during inspections. Maintenance tasks that used to require flipping through ledgers and drawings can be streamlined by centralized model-based management. For example, in bridge maintenance, marking damage locations on a 3D model and recording coordinates, photos, and inspection dates allows precise checks at the same location during future periodic inspections, aiding prioritization and budgeting for repairs. BIM/CIM can thus reduce life-cycle costs of infrastructure assets and enable preventive maintenance.

As described above, BIM/CIM delivers significant benefits in design quality improvement, construction productivity improvement, and maintenance efficiency. MLIT is paying attention to these effects and anticipates that BIM/CIM dissemination will bring about workstyle reform on construction sites, cost structure improvements, and enhanced safety in the future. Although BIM/CIM adoption is not simple, the benefits are substantial, making industry-wide engagement worthwhile.

Field Use Cases (Bridge Works, Tunnels, ICT Earthworks, etc.)

To better imagine the benefits of BIM/CIM, here are some field use cases. BIM/CIM is being utilized in diverse projects such as bridge works, tunneling, and ICT earthworks (information-driven earthworks).

BIM/CIM Use Cases in Bridge Construction

In the bridge sector, using 3D models from the design stage has produced dramatic effects. For example, in a highway bridge project in the Tokyo metropolitan area, multiple BIM/CIM model proposals were used to compare landscape and structural considerations when examining girder shapes, successfully selecting the optimal plan. BIM/CIM enables designers to visualize harmony with terrain and the surrounding environment during design, facilitating smooth consensus building among stakeholders. Domestic and international case studies show that bridge design firms that adopted BIM/CIM early reduced design errors by 85% and cut costs by 5–12%, achieving payback in 3–5 years. Specific benefits include:

• Advanced clash detection: Pre-discover clashes with existing infrastructure or other works (e.g., detecting collisions between pier foundations and underground utilities on the model and revising the design).

• Improved quality and safety: 3D rebar models enable inspection of rebar clashes and omissions, reducing construction defects and strength deficiency risks. Integration with structural analysis models can also optimize safety factors.

• Consensus building and communication: Using 3D models and finished-image visuals for explanations to clients and local residents makes it easier to obtain understanding and agreement.

• Shortened construction schedules: 4D simulation of bridge assembly sequences optimizes heavy equipment placement and material delivery planning, eliminating work inefficiencies. There are cases where the construction period was shortened by 40%, directly improving productivity.

Thus, in bridge construction, BIM/CIM consistently supports planning, design, and construction planning phases, enabling project-wide efficiency and sophistication.

BIM/CIM Use Cases in Tunnels and Underground Works

BIM/CIM is also beneficial in urban tunnel construction and underground space projects. 3D and 4D technologies are particularly powerful where spatial constraints are large and complex. For example, for an underground pedestrian passage construction around Shibuya Station on National Route 246, a construction plan using BIM/CIM was developed and implemented under extremely confined above- and below-ground conditions.

This project included the following advanced initiatives:

• Detailed 4D construction simulation: Large precast concrete members had to be installed sequentially at night. Time-based 3D simulations of installation procedures and heavy equipment movements were performed in advance, optimizing material delivery order and crane placement, which shortened installation days by 40% compared with the original plan.

• VR-based construction review: Simulation data was experienced in VR to identify inconsistencies in procedures and hazardous areas through simulated experience. This allowed early identification of risks that are hard to detect on paper plans, which informed safety measures.

• On-site AR utilization: Tablets with AR systems were used to project BIM/CIM models over the live camera view at the site. This visualized underground utility positions on the ground during excavation, reducing the risk of damaging pipes. AR also helped align understanding during coordination meetings with project stakeholders and neighboring businesses by sharing the completed-image AR model.

• Point cloud surveying and as-built management: After nightly work, the as-built status was scanned daily with scanners, and the resulting 3D point cloud data was overlaid on BIM models to verify construction accuracy. This allowed immediate understanding of construction errors and enabled PDCA feedback for the next day’s work.

Thus, for tunnels and underground structures, the combination of BIM/CIM with VR/AR and point cloud data has greatly contributed to effective space utilization and risk reduction. Even in confined underground spaces, digital technology makes the invisible visible, enabling safe and efficient construction.

ICT Earthworks Field Use Cases

ICT earthworks refers to earthwork operations that utilize information-driven construction technologies. It covers foundational earthwork processes like land development, excavation, embankment, and grading, leveraging 3D survey data and machine guidance (automatic control of construction machinery). BIM/CIM is deeply related to ICT earthworks, and using 3D terrain models and construction models created during design in the construction phase produces dramatic efficiency improvements.

Specific field examples, such as dam construction and road development sites, include the following practices:

• Linking 3D surveys and design data: Create detailed 3D terrain models from point cloud data acquired by drone photogrammetry or terrestrial laser scanners, and perform earthwork design based on those models. Designers calculate cut-and-fill volumes on BIM/CIM models and plan optimal construction methods.

• Machine guidance/machine control: Load 3D model data of the designed finished terrain into construction machines such as bulldozers and excavators. Machines linked to GPS or total stations guide the operator or automatically control operations to maintain the designed elevations and slopes, eliminating the need for labor-intensive batter boards (height reference stakes) and enabling batter board–less construction, reducing labor and shortening schedules.

• Efficient as-built management: During and after construction, measure the terrain again with drones or 3D scanners and verify deviations from design models. This speeds up as-built measurement tasks that previously required survey teams and enables efficient quality checks. According to materials from the Kanto Regional Development Bureau, using 3D design data and ICT surveying equipment significantly reduced the labor involved in as-built measurement work.

• Safety and labor reduction: Dangerous slope shaping tasks can be conducted remotely via machine control without people approaching the slope, enhancing safety and reducing required personnel, addressing labor shortages.

In ICT earthworks, 3D models created by BIM/CIM essentially become digital work instructions on site, and the processes of surveying → design → construction → inspection are seamlessly connected. MLIT also advocates “full promotion of ICT-utilizing construction,” establishing various guidelines and procedures. Prefectural development bureaus and prefectures are conducting trial projects and accumulating and disseminating know-how. ICT earthworks can be considered a practical form of BIM/CIM and is becoming the standard for future civil works.

Challenges and Solutions for BIM/CIM Adoption

Although BIM/CIM offers significant benefits, several challenges have been pointed out in its adoption. Below we summarize the main issues and possible solutions.

Main Challenges in BIM/CIM Adoption

• Shortage of personnel and skills: Creating and using 3D models central to BIM/CIM requires operation skills in specialized software and knowledge of 3D design. Currently, personnel who have mastered these skills are insufficient, and training systems are not yet adequate. Companies wanting to start BIM/CIM often face the barriers of “no one who can handle it” or “no time for training.” With few experienced staff to teach new graduates, knowledge transfer is also hampered.

• Software selection and compatibility: Implementing BIM/CIM requires dedicated software and tools, but a wide variety of products are available, and many wonder which to choose. In architecture, Revit and Archicad are representative, while in civil engineering Civil 3D and InfraWorks are typical, each differing in operability and strengths. Data compatibility between different software can also be low (for example, attribute information may be lost even via intermediate formats like IFC), causing problems when models cannot be shared with other companies.

• Cost and time burden: Creating 3D models requires extra effort and time, so short-deadline or low-budget projects may avoid it. Small- to medium-sized projects may have circumstances where “2D drawings are faster” or “there is no room for 3D work.” Initial investments can be high due to software license fees and high-spec PCs, posing hurdles especially for small businesses.

• Resistance on site: Some technicians who have worked with 2D drawings for years may feel resistant to 3D models or anxious about whether they can become proficient. It takes time to permeate new methods across a site, and lack of understanding from management or insufficient internal cooperation can hinder adoption.

Initiatives and Solutions to Address Challenges

Industry efforts are gradually progressing to solve these issues. Some directions are:

• Human resource development and enhanced training: MLIT, regional development bureaus, and construction organizations are holding BIM/CIM training and human resource development programs. For example, the Kinki Regional Development Bureau conducts hands-on training for BIM/CIM construction and 3D data handling as part of infrastructure DX talent development. Companies are also encouraging younger staff to learn 3D CAD and hiring mid-career specialists. Establishing internal BIM/CIM promotion offices to centralize knowledge and support departments is becoming more common.

• Use of adoption support tools: Software vendors are offering BIM/CIM solutions that are easier for beginners to use, such as tools that semi-automatically generate 3D models from existing 2D drawings or cloud platforms that integrate data from multiple software. The spread of open formats (IFC, etc.) and stronger software interconnectivity are expected to improve data compatibility. Outsourcing model creation to specialist firms or temporary staffing services can also allow companies without in-house skills to obtain BIM/CIM models.

• Phased introduction and management commitment: Rather than aiming for full implementation across all projects at once, starting with a single model project or a familiar type of work to trial and verify effects before gradual expansion is effective. Small starts build internal success experiences and reduce resistance. It is important for management to clearly drive DX and lead BIM/CIM adoption as a cross-functional project. A combination of top-down decisions and bottom-up collection of field needs is desirable.

• Utilization of national support measures: MLIT offers various support measures to promote BIM/CIM adoption, such as technical support, scoring incentives, and subsidy programs. For MLIT-managed projects, BIM/CIM initiatives may receive additional points in comprehensive evaluation procurement. The industry is also developing standard guidelines, publishing case studies, and providing portal sites for sharing knowledge. Actively referencing these public resources can aid corporate adoption plans.

Though challenges remain, specific solutions are emerging. BIM/CIM adoption requires time and effort, but as previously described, the value justifies the investment. Each company should advance step by step with methods suited to its circumstances to raise the industry’s baseline.

Latest BIM/CIM Technological Trends and Industry Trends

As of 2025, technological trends and industry movements surrounding BIM/CIM are becoming increasingly active. Below are some key trends.

Full Application of BIM/CIM and the Outlook for i-Construction 2.0

As noted earlier, from fiscal 2023 MLIT’s directly managed projects have begun the principle application of BIM/CIM, and full mandatory application is expected by 2027. This has a strong impact across the industry, and construction companies are accelerating responses. Both major general contractors and small and medium construction companies are moving toward BIM/CIM compatibility, also seen as a countermeasure to the “2024 problem” of labor environment reforms (stricter overtime regulations). Facing labor shortages and workstyle reforms, there is a sense of crisis that productivity must be improved through BIM/CIM to sustain operations.

The i-Construction 2.0 introduced in 2024 envisions next-generation smart construction technologies—remote supervision, automated construction, and AI use—based on BIM/CIM and ICT construction. For example, it is becoming realistic that real-time construction status will be reflected on digital twins and AI will monitor quality and safety and issue directives. A DX promotion headquarters has been set up within MLIT to coordinate public-private efforts for social implementation of digital technologies. Since BIM/CIM is a foothold for this, policy support is expected to continue.

Cloud Platforms and Data Sharing

Sharing and managing BIM/CIM models and point cloud data on the cloud is spreading. Design data previously handled in local CAD environments is being uploaded to cloud BIM platforms for project stakeholders to view and edit, becoming the mainstream. Examples include Autodesk BIM 360, Bentley iTwin, and domestic vendors’ BIM cloud services. Viewing 3D models in the cloud and holding online review sessions with comments has become possible, and remote collaboration between designers and constructors has progressed since the COVID-19 pandemic.

MLIT is also preparing standard delivery formats and checking tools for BIM/CIM data to facilitate smooth data sharing including clients. There is consideration for clients (administrations) to utilize BIM/CIM data after project completion to manage infrastructure assets, and BIM/CIM models may become substitutes for maintenance ledgers in the future.

Fusion with Cutting-Edge Technologies such as AR/VR and AI

BIM/CIM also has high affinity with other advanced technologies, and various integrations are being tested. For AR, as in the aforementioned Shibuya Station project, overlaying models on live site views via tablets is spreading. Projecting planned BIM models onto construction sites to check the structure under construction, or displaying underground utility positions during excavation for safety checks, is already at a practical level. VR is used for virtual construction planning experiences and operator training; heavy equipment operators can practice in VR before entering actual sites.

AI is being applied to analyze BIM/CIM models and construction data to optimize schedules and predict hazards. For example, Takenaka Corporation has trialed a digital twin for construction management where AI automatically diagnoses daily work risks. Incorporating various sensor data (vibration, strain, etc.) into BIM/CIM models for structural health monitoring supports AI analysis in maintenance.

Thus, while powerful on its own, BIM/CIM is becoming the hub of construction DX when combined with cloud, AR/VR, AI, IoT sensors, and robots. The industry trend is to adopt these comprehensively to advance smart cities and smart infrastructure management.

What Is LRTK: The Latest Positioning Solution Compatible with BIM/CIM

Next, we introduce “LRTK,” the subject of this article’s title. LRTK is a compact, high-precision positioning device that has emerged as a new surveying and positioning solution for the BIM/CIM era. Its technology has attracted attention as a means to innovate fieldwork in the context of MLIT-promoted i-Construction and infrastructure DX.

Basic Principles and Features of LRTK

In short, LRTK is a “palm-sized RTK-GNSS positioning terminal.” RTK (Real-Time Kinematic) is a technique that dramatically improves satellite positioning (GPS/GNSS) accuracy by applying real-time corrections from a base station. While regular GPS has errors on the order of meters, RTK can determine positions with horizontal and vertical accuracies on the order of several centimeters. LRTK miniaturizes RTK technology to the utmost degree so that anyone can easily use it on site.

Figure: A pocket-sized high-precision positioning device that attaches to a smartphone, “LRTK Phone” (an RTK-GNSS receiver dedicated to iPhone that attaches to an iPhone and turns it into a versatile surveying instrument you can carry anytime)

LRTK is a product line developed by Reflexia Inc., a startup originating from the Tokyo Institute of Technology, and the core device is called the “LRTK Phone.” The LRTK Phone is an ultra-compact RTK-GNSS receiver integrated into a dedicated smartphone case; attaching it to an iPhone or iPad instantly turns the smartphone into a centimeter-level surveying instrument. It weighs 125 g, has a thickness of about 13 mm (0.51 in), and includes a built-in battery—truly a pocketable surveying instrument. Using the dedicated “LRTK app,” users can execute positioning with one touch and record latitude, longitude, and elevation at high accuracy. It supports Japan’s geodetic system (JGD2011) and plane rectangular coordinate systems and automatically performs coordinate transformations and geoid height calculations during positioning, allowing use without specialized knowledge.

High precision is a major selling point. For example, the LRTK app includes a function that averages a certain number of measurements to improve accuracy; even if a single measurement has a horizontal error of about 12 mm (0.47 in), averaging 60 measurements yields a horizontal error of 8 mm (0.31 in). Vertical accuracy is also around 1 cm (0.4 in), approaching that of professional surveying instruments. Despite this precision, LRTK eliminates the complexity typical of traditional RTK survey instruments—results are obtained simply by pressing a button on a smartphone.

Another feature of LRTK is cloud integration of positioning data. Measured coordinates and memo information can be uploaded to the LRTK cloud (web platform) with one button, letting office PCs immediately confirm on-site measurement points. Points are plotted on cloud maps with titles, timestamps, coordinate values, and notes, enabling real-time data sharing between site and office. This aligns with BIM/CIM’s goal of linking field data and models and, as described later, serves as a powerful support tool for BIM/CIM adoption.

LRTK is also designed for robustness and field adaptability. The device itself meets dustproof and waterproof specifications (compliant with IP standards), making it suitable for dusty civil engineering sites and light rain. Proprietary technology that combines IMUs (inertial measurement units) enables stable positioning even near locations where GNSS is typically unstable, such as under viaducts or near tunnel entrances. It has self-estimation features to maintain position when signals are intermittent, making it applicable to tunnel construction and similar environments.

Overall, LRTK aims to be a universal surveying tool that allows “accurate positioning anytime, anywhere, by anyone.” As its developers have said, the product became an all-in-one surveying instrument reflecting users’ on-site needs. Specific functions include:

• Single-point positioning: Measure and record coordinates (latitude, longitude, elevation) of arbitrary points with one push. Automatic calculation of plane rectangular coordinates and geoid height.

• Continuous positioning / point cloud acquisition: Take continuous measurements at set intervals to obtain terrain point cloud data. By walking and collecting many points, it can be used for simple terrain scanning.

• Layout/position guidance: Input design coordinates (e.g., structure layout positions) in advance and guide users to those locations. The smartphone screen displays arrows and distances and notifies users when they reach a design point.

• Photo measurement and AR simulation: Tag high-precision position coordinates and orientation to photos taken with the smartphone camera and record them. It can measure object sizes in photos on-site and overlay design models (AR). For example, overlaying a design cross-section on a photo of an excavation site to confirm the finished image before work.

• Earthwork volume and distance calculation: Tools to compute distance, area, and volume (earthwork) from measured point data. Useful for rough quantity calculation on site.

• Cloud sharing and reporting: Positioning results can be shared immediately on the cloud, exported as CSV from the web, and report templates for deliverables are being developed.

Remarkably, LRTK is offered at a very reasonable price despite these functions. While exact prices are not publicized, the emphasis is on “making LRTK accessible to everyone,” with RTK receiver units and optional monopods provided at prices unimaginable for traditional equipment. Expensive instruments raise adoption barriers, but with LRTK, equipping every worker with one device could become realistic, ushering in an era where all site staff can perform measurements individually.

Comparison with Conventional Products (Accuracy, Price, Usability)

Compared to traditional high-precision positioning products (GNSS survey sets, total stations, etc.), LRTK offers the following advantages:

• Ease of handling: Traditional surveying often required stationary base stations and personnel with prisms, but LRTK completes surveying with a single smartphone. There are instruments like automatic-tracking total stations that enable single-person surveying, but equipment tended to be bulky. LRTK can be handled by one person with one hand, making it suitable for narrow sites and night work.

• Usability for beginners: Traditional survey instruments demanded expertise and experience, but LRTK’s intuitive smartphone app UI allows non-specialists to operate it easily. Complex procedures like base station setup and radio configuration are automated, lowering barriers to starting positioning. It can be used on site without training, so newcomers and people from other professions can handle it.

• All-in-one and versatility: Traditionally, different devices or personnel handled surveying, layout, and as-built measurement, but LRTK supports the entire workflow from surveying to as-built with a single device. Because of its versatility, it is sometimes called “the site’s pen-and-notebook,” meeting diverse positional needs.

• Accuracy and reliability: While traditional RTK-GNSS instruments are highly accurate, LRTK’s averaging function enables precision down to millimeter levels. IMU fusion enhances continuous positioning where satellite reception is unstable, giving it greater practicality than standalone GNSS devices. Stable positioning under viaducts and in forested areas—difficult for existing products—is achievable.

• Cost performance: Total stations or survey GPS sets can cost several million yen, but LRTK is considerably more affordable. Lower initial investment allows multiple units to be deployed, enabling simultaneous surveying at multiple locations without waiting times.

• Expandability: Because LRTK integrates with smartphones, software updates can easily add functions. The vendor plans to continue developing features based on field feedback, suggesting future enhancements such as real-time BIM model display during surveying or AI-based automatic anomaly detection.

Of course, conventional instruments have strengths: high-precision total stations can achieve sub-millimeter accuracy to prisms, and laser scanners can acquire high-density point clouds quickly. LRTK does not completely replace such specialized equipment, but it provides unprecedented value by enabling everyday surveying, layout, and recording tasks to be performed easily by anyone. Combining high precision with simplicity, LRTK is a revolutionary solution supporting construction site DX.

How LRTK Contributes to BIM/CIM Adoption (Use in Surveying, Design, Construction, and Maintenance Phases)

Now let’s consider specifically how LRTK supports BIM/CIM adoption across project phases. BIM/CIM depends on data continuity from survey and design through maintenance, and LRTK can act as a bridge for data at each stage.

Use of LRTK in the Surveying and Investigation Phase

The starting point of BIM/CIM is accurately understanding the site. LRTK enables high-precision, easy surveying and is highly effective in the survey phase.

For example, LRTK can be used to understand current terrain and structure placement needed during planning. Previously, designers conducting site checks might have used tape measures or handheld GPS, but with LRTK they can obtain accurate coordinates. Designers can carry a smartphone and measure key site points (boundaries, elevation differences, positions of existing structures), then share that data via the cloud for immediate office-based 3D modeling. Preliminary surveys no longer require waiting for specialized survey teams.

LRTK is also useful for formal control point surveys and terrain surveys. For drone photogrammetry, LRTK can quickly measure ground control points (GCPs) on site. One person can rapidly collect many points, improving aerial mapping accuracy and work efficiency. LRTK case studies report significant reductions in survey time—for example, in a railway construction site where RTK control points were established faster than conventional methods.

Survey points acquired with LRTK can be used as foundational data for BIM/CIM models. Shared via the cloud to design teams and imported as reference data into 3D models, LRTK helps create models that reflect actual field conditions from the planning stage. LRTK thus helps ensure MLIT’s emphasized continuity of information from survey → design → construction → maintenance. LRTK also provides precision-positioned data for geological and environmental survey points, reducing divergence between model and site and smoothing subsequent design and construction.

Use of LRTK in the Design Phase

LRTK is a powerful tool for designers and consultants. No matter how precisely one investigates on the drawing, how a design looks and fits on site is often only clear by visiting. Combining LRTK with AR makes on-site design verification straightforward.

For instance, when checking horizontal alignment in road design, something that appears fine in the model may obstruct sightlines or conflict with surroundings on site. A designer equipped with a tablet and LRTK can overlay a BIM/CIM model on the real scene. LRTK’s precise position and attitude measurement enable AR display that reflects the viewer’s viewpoint, making it immediately obvious if “a signboard will be hidden from this location” or “the retaining wall height will be about this much.” In the Shibuya Station project, tablet AR was used to confirm interfaces with adjacent redevelopment buildings on-site and adjust designs to avoid inconsistencies.

LRTK also provides rapid design-change feedback. If site conditions or constraints change during design, a responsible person can quickly measure additional points with LRTK and update the model. Traditionally, arranging outsourced surveys or re-surveys caused time lags for design revisions, but LRTK can enable near-real-time design updates. For example, if a pier foundation needs to be shifted slightly, LRTK can immediately measure surrounding clearances and interfering objects, update the model, and allow immediate safety calculations—enabling swift PDCA cycles.

LRTK contributes to consensus-building unique to BIM/CIM. At resident briefings or coordination meetings, showing design location and height on site using LRTK can communicate “a structure of about this height will be built here.” Displaying AR models on a smartphone clarifies information that flat plans cannot convey. LRTK’s portability allows designers to use it for on-site explanations themselves.

Use of LRTK in the Construction Phase

The construction phase is where LRTK’s value is most evident. Many on-site tasks involve positional information—layout, as-built verification, etc.—traditionally performed by specialist surveyors. With LRTK, each field technician can perform surveying tasks.

First, consider pre-construction layout (stakeout). Traditionally, specialists marked positions and elevations using strings and stakes based on design drawings. With LRTK, input design coordinates into the device and follow the guidance to mark accurate positions. For example, when marking center points of road curves or column locations, the smartphone notifies users as they approach the target point, enabling those with little surveying experience to stake out accurately. This not only improves construction accuracy but also reduces interruptions due to waiting for surveying, shortening schedules.

Next, as-built verification during construction. For items that require immediate post-construction verification—concrete pours, backfilling, pavement thickness—LRTK is powerful. For instance, to check whether a road pavement meets the specified thickness, measure the finished elevation with LRTK and the app will compute thickness (difference from reference height). Results are shared immediately to the cloud so managers and quality staff can check in real time. Tasks that previously required waiting for specialist survey results can be confirmed the same day, enabling prompt corrective action.

LRTK also aids safety and schedule management. Using AR, project teams can project 3D models of underground gas pipes during excavation to warn workers, or enable equipment operators to identify unseen underground obstacles. Attaching high-precision coordinate tags to 360-degree or progress photos provides trustworthy records for progress and quality management. Comparing point cloud data acquired by LRTK with design models makes it easy to check for over-excavation or deviations.

At project closeout, LRTK can help prepare electronic deliverables. Measuring coordinate points with LRTK and using them directly in deliverable documents reduces conversion effort. For projects delivered with BIM/CIM models, LRTK measurement values can update models to produce accurate as-built (as-built model). LRTK thus acts as a hub keeping the field and digital models synchronized throughout construction.

Use of LRTK in the Maintenance and Management Phase

For BIM/CIM-based maintenance, how inspection data are incorporated into models is critical, and LRTK supports agile data collection.

For example, in a bridge periodic inspection, if a crack or displacement is found, measuring its position with LRTK records not only latitude and longitude but the exact place on the bridge model (e.g., the nth girder of span X where a crack of Y mm exists). During the next inspection, the same spot can be rechecked precisely, simplifying monitoring of damage progression. Damage coordinates and photo-tagged notes collected with LRTK can be shared via the cloud, quickly disseminating information among maintenance staff.

LRTK is also powerful in post-disaster infrastructure inspections. After an earthquake, measuring road collapses or bridge deformations across wide areas using LRTK allows rapid plotting on digital maps to help formulate early restoration plans. Similarly, after typhoons, accurately locating river facility breaches aids prompt response. Previously, initial recovery was delayed waiting for surveying, but LRTK enables quicker first responses.

In maintenance, the accumulated data’s use is key. Feeding LRTK-collected inspection data back into BIM/CIM maintenance models enables time-series tracking of structure conditions and digital asset management. For example, tunnel displacement measurements can be color-coded on models, or road subsidence visualized as heat maps; advanced analyses require precise base data. LRTK can also function like an IoT sensor, supporting maintenance DX.

Finally, eliminating dependence on individual experience is important in maintenance. Converting experience-based inspections into digital data addresses generational transitions and staff shortages. Large datasets collected by LRTK can later be used by AI to assist in deterioration forecasting and repair planning. A digital twin combining BIM/CIM models with LRTK data makes predictive maintenance and optimized inspection intervals more feasible.

In summary, from survey to maintenance LRTK’s use cases show it bridges the field to the digital world by delivering real-time field data into the digital realm and realizing digital design information on site. By supporting data collection and feedback at each BIM/CIM stage, LRTK can maximize the effects of BIM/CIM adoption.

Conclusion: Take a Step Toward the Future Site — Experience the BIM/CIM Era with LRTK

This article quickly covered BIM/CIM definitions, benefits, case studies, challenges, the latest trends, and the LRTK solution. The construction and infrastructure industry is now entering a period of digital innovation. With MLIT’s strong promotion, BIM/CIM will soon be commonplace in all projects. In this context, the ability of individual field technicians to master digital tools will be a key to success.

LRTK has emerged as a tool enabling field personnel to experience and practice DX. Pulling a smartphone from your pocket and pressing a button to obtain precision data that previously required specialist surveying is a scene unimaginable a few years ago. Try a simple LRTK survey on a familiar plot: quickly measuring elevation differences or distances and uploading them to the cloud will likely make you exclaim, “I can digitize this so easily!” The convenience of completing tasks that once required paper, pen, and tape measures with a single smartphone is addictive once experienced.

To fully realize BIM/CIM benefits, field sites must first possess digital data. LRTK powerfully supports that first step. If your company or department is considering BIM/CIM adoption, try using LRTK in site surveys or construction management. Its ease of adoption means less resistance on site and a tangible sense of labor savings and efficiency improvements. As the saying goes, seeing is believing—the power of digital construction becomes evident once you use it. Fortunately, LRTK is offered at a price point accessible to many, and equipping one device per person is no longer a dream.

Finally, remember that tools like BIM/CIM and LRTK are means, not ends. The true goal is to create safer, more productive sites, build good infrastructure efficiently, and use it wisely for a long time. Introducing new technology brings uncertainties and challenges, but for the bright future ahead, start incorporating digital technologies where possible. Experiencing high-precision surveying with LRTK is an ideal first step. Take this opportunity to open the door to site DX and experience the BIM/CIM world that will likely become tomorrow’s norm. You will surely be surprised and attracted by the seamless connection between site and digital.