CIM Comparison Table: Differences Among Major Tools and Why LRTK Is Chosen

In recent years, CIM (Construction Information Modeling) has attracted significant attention in the construction industry. The Ministry of Land, Infrastructure, Transport and Tourism has been promoting the use of CIM, and from fiscal year 2023 the principle application of CIM in directly managed construction projects (effectively mandatory) began, accelerating on-site adoption. CIM, which uses three-dimensional (3D) models to centrally manage information from design through construction and maintenance, is expected to be the trump card of digital reform that contributes to improved construction efficiency and enhanced quality control. Behind this is the issue of the construction industry's chronic labor shortage and the deepening decline in productivity, and greater demand is being placed on innovation through digital technologies (infrastructure DX).

That said, to truly utilize CIM on-site, it is essential to accurately digitally measure actual site conditions and synchronize them with design data without any discrepancies. Selecting the surveying and measurement tools that make this possible is the key to successful CIM implementation. The digital surveying technologies currently available range from conventional surveying instruments to drones, 3D scanners, AR devices, and next-generation smartphone-mounted tools, each with its own areas of strength and characteristics. In this article, we organize the differences among the main tools and solutions that support on-site CIM use, including a comparison table. We then explain why the new tool "LRTK" (エルアールティーケー), which has begun to be adopted at many sites in recent years, is being chosen.

What is CIM?

CIM is an abbreviation of "Construction Information Modeling" and is a method for utilizing three-dimensional (3D) digital models in construction projects. It is a concept that applies BIM (Building Information Modeling), which has become widespread in the building sector, to the civil infrastructure sector, and by centrally managing 3D models and associated information for the planning, design, construction, and maintenance of bridges, roads, dams, and other works, it aims to streamline and enhance operations. Traditionally, information was shared by producing two-dimensional drawings and reports for each phase, but with CIM an integrated 3D model is shared by all project stakeholders, enabling decision-making based on information that is always up-to-date and consistent, which leads to reduced errors and rework.

The Ministry of Land, Infrastructure, Transport and Tourism has been actively promoting the introduction of CIM as part of its i-Construction initiatives, and from fiscal 2023 the use of CIM has been made essentially mandatory for directly managed public works. Going forward, the scope is expected to expand to local governments and the private sector, and CIM is becoming an unavoidable trend at construction sites in Japan. In addition, the government is advancing support measures for adoption, such as developing standards and guidelines for CIM use and publishing an information-sharing portal site.

Key Tools and Solutions Supporting CIM Worksites

To maximize the benefits of BIM/CIM, it is necessary to maintain accurate data synchronization between the site and the design model at all times. However, in actual implementations there are often issues such as discrepancies between survey data and 3D models and time lags in information sharing between the site and the office. To address these issues and make effective use of CIM on site, it is important to accurately and rapidly digitize the conditions of the physical space and reflect them in the model. The various surveying and measurement tools that have emerged for this purpose each have different characteristics and advantages and disadvantages. Here, we introduce the main types of technologies and tools that support the use of CIM and examine their differences.

1. Conventional surveying instruments (total station and GNSS surveying)

For many years, specialized instruments such as total stations and high-precision GNSS receivers have been used for surveying on construction sites. These conventional surveying instruments can achieve high-precision measurements at the millimeter-to-centimeter level, but they require expensive equipment and specialized expertise. For example, assembling a high-precision GNSS positioning set or a complete total station setup can require an initial investment on the order of several million yen. Measurement work also requires experienced surveyors, and tasks such as setting up tripods, establishing control points, and post-processing data take considerable time and effort. With the conventional approach of bringing field-acquired data back to the office for drafting and modeling, it can take days to weeks to reflect measurements into design, leaving challenges for real-time CIM utilization.

2. Drone aerial photography (photogrammetry)

In recent years, photogrammetry using drones has also become widespread. This method uses a camera mounted on a drone to photograph the entire site from above and generates 3D models (point cloud data and orthophotos) from the obtained set of images. It has the advantage of enabling a quick overview of extensive terrain and is effective for surveying locations that people cannot enter. On the other hand, high-quality aerial imaging requires specialized drone platforms and surveying cameras and software, which entails a certain level of equipment investment and operator skill. It is also easily affected by conditions such as weather and flight permissions, and the post-flight data processing takes time. Because analyzing the completed 3D model on a PC is necessary to incorporate it into design, real-time capability is limited.

3. 3D laser scanner

Ground-based 3D laser scanners (terrestrial LiDAR) are also used as a measurement method for CIM. A laser scanner mounted on a tripod rotates while scanning its surroundings, and by acquiring precise point cloud data consisting of millions of points, structures and terrain can be recorded in 3D with high accuracy. Its measurement accuracy and level of detail are unmatched, but challenges include the equipment being very expensive and bulky, and the data processing being complicated. High-performance scanners can cost tens of millions of yen, and the point cloud files obtained from each scan are huge, making integration and noise processing with specialized software indispensable. While there is the advantage of being able to measure large areas quickly at once, transporting and setting up the equipment and integrating scans from multiple locations take time, and it is often difficult to confirm results on-site in real time.

4. AR-type positioning devices

AR (augmented reality)-type positioning devices that have emerged in recent years are also one of the tools that support CIM utilization. They combine dedicated tablets or goggle-type terminals with high-precision GNSS receivers, enabling digital 3D design models to be overlaid on the actual site scenery. Because 3D models can be viewed on-site while performing stakeout (marking) and as-built verification, they enable intuitive construction management. However, these devices themselves are expensive (on the order of several million yen), and calibration work or marker installation may be required to align the model with the actual site. While the ability to display AR in real time is advantageous, they are not suitable for recording the entire site as with point cloud surveying, and are rather positioned as tools for model visualization and verification.

5. Smartphone-mounted LRTK

LRTK is a new surveying solution developed by a venture company originating from Tokyo Institute of Technology, used by attaching a compact RTK-GNSS receiver to a smartphone or tablet. Its all-in-one design enables centimeter-level positioning (half-inch accuracy), point cloud measurement, and even AR display with a single smartphone. When you launch the dedicated app and attach the receiver, high-precision positioning starts automatically, and then you can simply hold up the smartphone and walk to scan the surrounding terrain and structures to create 3D models. Acquired data can be shared to the cloud instantly, allowing the latest information measured on site to be checked from an office PC at that very moment. Achieving accuracy equivalent to total stations and 3D scanners with a palm-sized device, and offering ease of use that requires no complicated initial setup, it is attracting attention as a groundbreaking tool that promotes DX in the field.

Comparison Table of Major Tools (Cost, Usability, Immediacy)

The characteristics of each solution, summarized from the perspectives of implementation cost, ease of operation, and the speed at which data is reflected, are as follows.

Why LRTK Is Chosen

Among the many surveying solutions, LRTK can provide outstanding value for the following reasons:

• Affordable initial cost: Traditionally, acquiring centimeter-class GNSS receivers (centimeter-level accuracy (half-inch accuracy)), 3D scanners, and AR equipment required a substantial upfront investment. LRTK can be introduced relatively inexpensively as an external device for smartphones, and because a single unit can serve multiple functions, it also reduces the cost of acquiring separate pieces of equipment. By enabling the use of existing smartphones instead of preparing multiple expensive dedicated devices, it is a cost-effective solution.

• Compact and highly portable: The LRTK receiver is lightweight and slim at about 165 g, compact enough to fit in a pocket while attached to a smartphone. It has the agility to be quickly taken out and used for measurements whenever needed, eliminating the burden of carrying a tripod while moving around a site. Because it can be easily carried by a single person and used anywhere, site workers can carry one unit each ("one per person") and perform surveys instantly when needed, realizing an ideal style.

• Intuitive and easy operation: The dedicated smartphone app is designed to be easy for non-specialist users on site to operate. Complex settings are automated, and positioning begins simply by launching the app and pressing a button. You can record location information just by pointing the device at the point you want to measure, and point cloud scanning and marking of stake positions can be done by following the on-screen guidance. In addition, distance calculations between measured points and conversion to coordinate systems are automated, enabling processes that previously relied on manual calculations or spreadsheet software to be completed on site. Measurement data can be sent to the cloud with a single tap, eliminating the need for cumbersome calculations or file conversions. Its ease of use—allowing immediate proficiency without specialized training—and the low barrier that lets anyone on site take on surveying tasks are highly valued.

• Real-time information sharing: Position information and point cloud data acquired with LRTK can be uploaded to the cloud on site and shared. Because PCs and tablets in remote offices can immediately check the latest data, the field and design personnel can always refer to a single, up-to-date source. This eliminates the hassle of "taking measured data back for drafting and reporting," and if conditions change on site the model can be updated immediately and shared with all stakeholders. Real-time coordination speeds up decision-making and directly reduces rework and errors. In practice, there are reports that pile-driving (layout marking) work that used to take half a day was completed in a short time using LRTK's AR function, and human errors were greatly reduced.

• Professional-grade high accuracy: Despite being a compact device, its positioning accuracy is first-class at approximately 1-2 cm (0.4-0.8 in), rivaling conventional surveying instruments. Multi-band GNSS and RTK methods enable acquisition of highly accurate absolute coordinates, and because it also supports correction information services (for example the QZSS "Michibiki" CLAS signal), it can maintain centimeter-level (half-inch-level) positioning even in mountainous areas outside communication coverage. Thanks to the high-precision alignment, the AR function of LRTK can always overlay the digital model and the real object without any misalignment. There is no need to install dedicated markers or perform complex calibrations each time, and because it provides stable positioning, it can be used with confidence for on-site inspections.

Furthermore, LRTK can be used in combination with other technologies, such as drone aerial photography and high-performance laser scanners, giving it the flexibility to be used all-round—from wide-area terrain surveying to detailed inspections. Its versatility, allowing it to handle a wide range of tasks with a single LRTK—from small-scale construction work to large-scale projects—is a major advantage on-site. As described above, LRTK is a rare solution that combines “high accuracy” and “ease of use.” Other companies' products—such as dedicated tablet-type AR devices and expensive 3D scanners—are each single-function, and there are few products that, like LRTK, excel in overall capability and are designed from the on-site perspective. That is precisely why it has sparked a quiet boom in construction management sites, and why more engineers feel, “I want to have one as my own.” Cases where LRTK is chosen as the new standard tool for leveraging CIM on-site are steadily increasing.

Summary: Getting Started with Simple Surveying Using LRTK

As CIM adoption ramps up, choosing the tools that support on-site DX is crucial to maximize its benefits. In this article, we compared the features of the major CIM-compatible tools and found that LRTK offers particularly strong advantages. LRTK bridges the field and digital models in real time and provides an environment where anyone can easily perform surveying and utilize 3D data. As the use of digital twins that synchronize the physical space and models expands, it is no exaggeration to say that real-time measurement technologies like LRTK will hold the key to on-site DX. Surveying, which has until now been left entirely to specialists, can be carried out easily in-house using LRTK. Why not first try a simple survey with LRTK? With the simplicity of starting with just a smartphone, you will surely be able to experience the first step toward on-site DX. We encourage you to realize efficiency gains and quality improvements at your site as well.