Exhibiting at CSPI: Accelerating On‑Site DX with High‑Precision GNSS × Cloud Integration

At construction and surveying sites, improving productivity and promoting DX (digital transformation) are major themes. The Construction and Surveying Productivity Improvement Expo (CSPI Expo) is an exhibition where the latest technologies and solutions gather. At this year’s CSPI Expo, various technologies that accelerate on‑site DX are attracting attention, and among them, solutions combining high‑precision GNSS (Global Navigation Satellite System) and cloud integration are especially in the spotlight.

This article explains evolving GNSS positioning technologies (particularly RTK and the new method LRTK) and how they differ from traditional total stations and typical GPS positioning, and considers how cloud integration can realize on‑site operational efficiency and remote data sharing. It also introduces examples and features of on‑site DX using the latest technologies, such as 3D point‑cloud scanning and pile/stake guidance by AR that are now possible with familiar smart devices like iPhone and iPad.

Furthermore, through concrete use cases across surveying, design, and maintenance management, we examine the ease of use that performs well even with small or solo crews and the cost advantages compared to conventional equipment. Against the background of on‑site challenges such as labor shortages, an aging workforce, and increasing task complexity, we organize the significance of these solutions and finally introduce a simple surveying system utilizing LRTK.

Evolution of GNSS Technology and Differences from Traditional Methods

First, let’s look at the advances high‑precision GNSS positioning brings to the field and how it differs from traditional surveying equipment. Surveying using GNSS has increasingly been adopted on sites as its accuracy has improved in recent years. In particular, GNSS positioning using Real‑Time Kinematic (RTK) methods has become widespread as a technique that achieves centimeter‑level accuracy by using correction information from a base station.

With conventional optical surveying (total stations, etc.), two people working together and complex equipment setup and calibration were necessary for high accuracy. Also, standalone GPS receivers typically have errors on the order of 5–10 meters, making them unusable for tasks requiring centimeter accuracy such as map creation or staking out. Therefore, high‑precision positioning required costly RTK‑capable GNSS equipment, and specialized operations like communication with a base station and obtaining correction data over a network were necessary.

In recent years, a new method called LRTK has also emerged to address these issues. LRTK combines a compact high‑precision GNSS receiver with a smartphone to more easily achieve accuracy comparable to conventional dedicated equipment. As will be described later, by utilizing multiple satellite frequencies and satellite augmentation signals, LRTK can confine errors to a few centimeters, including vertical positioning that was difficult with conventional GPS.

The main differences between traditional methods and GNSS surveying can be summarized as follows:

• Optical surveying such as total stations: High accuracy, but requires large equipment and target prisms so two‑person teams are standard. Each measurement requires setup and line‑of‑sight, and periodic calibration also takes time.

• General GPS positioning: No specialized equipment required and convenient, but errors are large (around 5–10 m) and vertical measurement accuracy is insufficient. It cannot be used for tasks requiring centimeter accuracy such as topographic mapping or staking out.

• RTK‑GNSS surveying: Uses a GNSS base station and rover with real‑time corrections to reduce positional errors to a few centimeters. Highly accurate, but equipment is expensive and operation requires specialized knowledge; a reliable communication environment is also essential.

• Positioning with LRTK: Achieves RTK‑equivalent centimeter accuracy using a smartphone and an ultra‑compact GNSS receiver. It also leverages augmentation signals such as QZSS (Michibiki), enabling stable positioning even in mountainous areas with limited signal coverage. It is less expensive than conventional equipment and easier to carry and operate.

Thus, GNSS technology has progressed dramatically, making high‑precision positioning accessible even without dedicated equipment. While advances in smartphones and communications infrastructure have enabled this, integration with the cloud also plays an important supporting role. Next, let’s look at efficiency gains through cloud utilization.

Efficiency Gains and Remote Sharing Enabled by Cloud Integration

Even if high‑precision on‑site data is obtained, true efficiency gains do not follow unless that data can be used quickly. The key here is integration with cloud services. If positional information and point‑cloud data collected on site are uploaded to the cloud immediately, office staff and stakeholders at other locations can share results in real time.

Cloud utilization offers the following benefits:

• Immediate data sharing: By syncing survey data collected on site to the cloud, teams in remote locations can share information in real time. This dramatically reduces the time spent waiting to verify survey results or make decisions.

• Remote collaboration: Data uploaded to the cloud can be viewed by stakeholders over the internet right away. There is no need to install dedicated software; 3D point clouds and survey results on maps can be checked from a browser. Clients and designers can grasp the latest situation from the office and issue appropriate instructions without visiting the site.

• Centralized data management and analysis: Survey data accumulated in the cloud is managed centrally and can be retrieved and analyzed as needed. For example, acquired point clouds can be overlaid with multiple models in a cloud 3D viewer to measure arbitrary distances, areas, or volumes. Accumulating time‑series data also helps track changes over time and manage as‑built conditions.

In this way, cloud integration makes the workflow from surveying to data sharing and analysis seamless, enabling efficient operations that transcend the boundaries between the field and remote locations.

New On‑Site DX Features Enabled by iPhone and iPad

So, what specific new on‑site DX features become possible in an environment that leverages high‑precision GNSS and the cloud? The keyword is smartphone utilization. Modern iPhones and iPads are equipped with high‑performance cameras and LiDAR sensors, and when combined with a small GNSS receiver device, they become powerful mobile surveying tools.

Here are the main features that can be realized with a single smart device:

• High‑precision coordinate measurement: While receiving real‑time GNSS corrections, latitude, longitude, and height can be measured and recorded with one tap. Support for Japan’s plane rectangular coordinate system and automatic geoid height calculation means the acquired coordinates can be used directly as results for public surveys.

• 3D point‑cloud scanning: By capturing the surroundings with an iPhone’s LiDAR scanner or camera while simultaneously attaching high‑precision position data in real time, an absolute‑coordinate point‑cloud model can be easily generated. Without special laser scanners or drones, simply walking with a smartphone enables planar and volumetric measurement of structures and terrain, and analyses such as earthwork volume calculations can be performed immediately after acquisition.

• Stake/pile guidance (coordinate navigation): If the coordinates of stake/pile positions or reference points specified in the design are input, arrows and distance information are displayed on the smartphone screen to guide the user to the target point. Workers can follow on‑screen directions to identify positions for stake setting with centimeter‑level accuracy. This enables accurate marking without advanced surveying skills, reducing labor for staking tasks.

• AR visualization of design data: If design drawings or 3D model data are imported into a smartphone app, they can be overlaid on live site imagery. AR displays aligned with real‑world coordinates provided by GNSS make it easy to confirm at a glance whether structures are positioned and elevated as designed. It is also possible to visualize registered underground utilities or boundary lines in the view to warn during excavation or assist as‑built inspections.

• Photo measurement and record keeping: Photos taken with a smartphone camera can be automatically tagged with high‑precision capture coordinates and orientation information. Because it is immediately clear on a map where and in which direction a photo was taken, time‑series comparisons and creation of reports are streamlined.

In this way, measurement and design tasks that previously required dedicated equipment and skilled personnel can now be handled one after another with a single smartphone. Field engineers can carry their own surveying tools and use them when needed. The era of the mobile surveying device as "one device per person" is becoming a reality.

Next, let’s look at where these technologies are particularly effective across surveying, design, construction, and maintenance.

Use Cases in Surveying, Design, and Maintenance

DX tools using high‑precision GNSS and smartphone apps are useful in many aspects of civil engineering and construction projects. Representative use cases include:

• Surveying (topography and as‑built/quality control): New technologies greatly improve efficiency in site topographic surveys and as‑built management. For example, walking a site with a smartphone to scan point clouds digitizes the entire terrain in detail, whereas before only representative points were measured and the rest inferred. As a result, earthwork volume calculations and section creation can be done on the spot, reducing missed measurements and estimation errors.

• Design and construction: At the design stage, site point‑cloud data can be used to simulate how a planned structure fits with the surroundings. During construction, overlaying the design model in AR allows immediate confirmation that a structure’s position and elevation match the drawings. Early detection of errors or deviations helps prevent rework and ensures quality.

• Maintenance management and disaster response: These tools are also powerful for infrastructure inspections and disaster site surveys. Regular scanning of existing structures such as bridges and tunnels enables detection of displacement or signs of deterioration from the data. In the event of a disaster, quickly surveying the damaged area with point clouds and sharing the data via the cloud speeds up recovery planning. The ability to record site conditions safely while significantly reducing manpower and time is highly valued.

Thus, smart GNSS and 3D technologies can be applied across a project’s lifecycle, contributing to fundamental efficiency improvements and higher sophistication of work.

Portable Surveying Tools That Support Small Crews and Solo Work

Another major benefit of on‑site DX tools is that they enable work to be completed by small teams or individuals. With worsening labor shortages, the ability for each person to handle advanced surveying tasks is a significant advantage.

• Single‑person surveying: Traditionally two people were required to operate survey equipment and set prism targets, but a smartphone combined with a GNSS device allows one person to perform observations. For staking, attaching a smartphone to a monopod provides coordinate guidance so the target position can be established accurately without an assistant.

• Reduced burden of equipment transport: The compactness of the entire system means heavy tripods and large surveying instruments do not need to be carried to the site. This shortens setup time and makes measurements at heights or in confined spaces easier.

• Cost advantages: The combination of a small GNSS receiver and a smartphone lowers initial acquisition costs compared to conventional surveying equipment. Completing surveys in‑house can also reduce outsourcing costs. There is less effort required for calibration and maintenance, contributing to lower total cost of ownership.

• Ease of learning: Intuitive smartphone app interfaces are designed to be user‑friendly even for staff with limited expertise. By following Japanese UI and clear guidance, positioning and data collection can be performed, minimizing training time. The familiarity of IT to younger engineers reduces resistance and helps with knowledge transfer.

• Safety and work efficiency: Being able to complete tasks with a minimal crew reduces personnel exposure to hazardous sites. With fewer people required, labor can be allocated elsewhere, and the number of survey points per hour increases, contributing to shorter schedules and improved productivity.

With portability and simplicity, these new surveying tools are powerful solutions for sites that require labor saving and cost reduction. Adoption of such technologies is already underway.

Adoption by Municipalities and Private Sector, and Use in Disaster Response

How are these technologies actually being introduced and used on the ground? Here are some examples:

• Adoption by local governments: Progressive municipalities have begun actively using on‑site DX tools for disaster response and operational efficiency. For example, Fukui City in Fukui Prefecture introduced a smartphone‑based surveying system in 2023 and had staff rapidly measure the locations of collapsed houses and ground deformation after an earthquake. Measurement data were shared to the cloud immediately, allowing the city offices to grasp the situation and use it for recovery planning. This enabled initial response without waiting for specialists, reportedly shortening recovery time and reducing costs.

• Use in private construction: Construction and surveying firms are also introducing DX tools that enable efficient measurement with small crews. For instance, a certain small construction company adopted smartphone surveying for as‑built management of its own projects, enabling site supervisors to perform measurements in a short time that were previously outsourced. Major general contractors have also begun trial introductions, creating new workflows such as young engineers using AR surveying tools for quality checks.

• Effectiveness in disaster sites: As in the Fukui City example, smartphone surveying is starting to be used for rapid recording of disaster sites. For example, in mountainous areas after a landslide, personnel who reach the site can immediately survey the affected area with point clouds and share the data via the cloud. Surveying that once required large teams and much time has been dramatically sped up, making this a solution closely linked to rapid recovery.

From public agencies to private companies, adoption of on‑site DX solutions is progressing. Especially in disaster response, the combination of high‑precision GNSS and smartphones is attracting attention as a means to enable rapid information collection and sharing.

The Significance of DX in Addressing Labor Shortages and Aging Workforce

In Japan’s construction industry, the aging of skilled technicians and labor shortages are serious problems. As construction management and surveying tasks become more advanced and complex, securing and training the personnel to handle them has not kept pace.

Under these circumstances, the role of easy‑to‑use surveying tools and on‑site DX technologies is significant. If less experienced staff can obtain high‑precision measurement results quickly with digital equipment, it can reduce the burden on veterans and help standardize quality. For older skilled workers, substituting physically demanding tasks with smartphones and lightweight equipment can reduce physical strain while allowing them to continue contributing their expertise on site.

Moreover, introducing the latest technologies on site is attractive to younger generations and can help promote recruitment and improve the industry’s image. Digitalizing the field with tools that the smartphone generation can use comfortably will help secure future talent.

Thus, on‑site DX solutions do more than improve operational efficiency; they help address structural issues in the industry. Their importance in maintaining and improving productivity and safety on site is expected to grow.

Simple Surveying Solutions Enabled by LRTK

Finally, as a culmination of the high‑precision GNSS, smartphone, and cloud integration discussed so far, we introduce LRTK. LRTK (pronounced "L‑R‑T‑K") is an innovative smartphone surveying system developed by Refixia, a startup spun out of Tokyo Institute of Technology. By simply attaching an ultra‑compact RTK‑GNSS receiver (weighing approximately 165 g) to an iPhone, centimeter‑level positioning comparable to traditional surveying instruments becomes possible. In addition, dedicated apps and cloud services provide one‑stop capabilities for 3D point‑cloud measurement, AR stake guidance, and cloud data sharing.

With the LRTK system, the complicated procedures from initial positioning setup to sharing results are greatly simplified, creating a simple surveying solution that anyone on site can use. Because users can perform high‑precision surveying by following on‑screen instructions without specialized training, it is easy for small contractors and municipalities to adopt, and it is already being used in various locations.

At our CSPI Expo booth, we will demonstrate the latest on‑site DX solutions using the LRTK system. Please visit the venue to see how much high‑precision measurement can be achieved with just a smartphone.