GNSS端末で点群計測革命！ドローンなしで3D測量を実現

In recent years, 3D surveying using three-dimensional point cloud data has rapidly spread in construction sites and surveying. Point cloud measurement, which accurately visualizes the field for construction quality control, earthwork volume calculation, and understanding the shapes of structures, is a key technology for on-site DX (digital transformation).

However, traditionally, obtaining these point clouds required specialized equipment such as drones or expensive 3D laser scanners, which were not easily handled by everyone.

This article introduces a new point cloud measurement method achieved by combining a GNSS terminal with a smartphone. This enables numerous benefits such as “no drone needed,” “anyone can easily acquire 3D point clouds,” “instant on-site volume and area calculation,” and “cloud integration enabling AR display and progress management.”

As a concrete example, we will look at the functions and effects of the compact RTK-GNSS receiver LRTK, and examine a new era of 3D surveying that does not rely on drones.

従来の3D測量の課題：ドローンや高価機材が必要だった

Until now, high-precision 3D surveying on site required specialized teams and equipment. Typical methods included drone photogrammetry and fixed laser scanners for point cloud measurement. However, these conventional methods had the following challenges.

• Cost and equipment hurdles: High-precision laser scanners and industrial drones are very expensive. Not only do they require significant investment and maintenance costs, but training is also necessary to operate them. Many small-to-medium sites hesitated to adopt them from a cost-effectiveness perspective.

• Specialized personnel and labor: Drone flight requires obtaining qualifications and permits (in Japan, since 2022, drones weighing over 100 g must have a license and aircraft registration), and operations often need a multi-person team and strict safety management. Laser scanner measurements also required expertise for setup, teardown, and point cloud data processing. They were not something anyone could immediately handle, so site personnel could not casually perform repeated surveys.

• Data acquisition range and timeliness: Drone photography captures from the air, so obtaining point clouds for areas where GNSS reception is poor or the view is obstructed—such as the underside of bridges, indoors, or under trees—can be difficult. Manual point surveying provides only limited point information, making comprehensive three-dimensional understanding challenging. Large-scale point cloud measurements also required scheduling a separate surveying crew to visit, so even if you needed data immediately, obtaining and using it in real time was difficult.

Thus, traditional 3D point cloud measurement depended on expensive equipment and specialized technicians, creating barriers to “anytime, immediate, and casual” use in everyday site operations.

GNSS端末＋スマホで変わる点群計測

This situation is being transformed by a new approach: GNSS terminal + smartphone. By combining a smartphone’s camera or LiDAR sensor (light detection and ranging) with a GNSS (Global Navigation Satellite System) receiver that achieves centimeter-level accuracy (cm level accuracy (half-inch accuracy)), high-precision 3D point clouds that previously required specialized equipment can now be obtained by anyone with ease.

One notable recent development is the advent of compact RTK-GNSS receivers that can be attached to smartphones. RTK (Real Time Kinematic) is a technique that corrects GNSS positioning errors and achieves centimeter-level accuracy in real time. Previously, fixed base stations and large antennas were required, but technological advances have miniaturized RTK-capable receivers down to business-card size so they can be attached to smartphones.

For example, LRTK is an ultra-compact RTK-GNSS terminal that can be attached to an iPhone or iPad, turning a smartphone into a surveying instrument with centimeter-level accuracy (cm level accuracy (half-inch accuracy)). Simply attach LRTK to the smartphone and launch the dedicated app, and pocket-sized hardware can perform everything from high-precision coordinate acquisition to 3D point cloud scanning. The smartphone’s built-in LiDAR scanner or camera scans the surroundings while LRTK provides absolute positions (coordinates in the global geodetic reference), so point cloud data are always tied to accurate global coordinates. This eliminates the need for time-consuming alignment when comparing measured point clouds later with design drawings or other survey data. Truly, a palm-sized GNSS terminal combined with a smartphone is sparking a “revolution in point cloud measurement.”

ドローンなしでも誰でもできる簡単3D測量

The greatest advantage of point cloud measurement using a GNSS terminal + smartphone is that on-site personnel can perform it without specialized skills. Traditionally, 3D surveying often required licensed surveyors or drone pilots, leading to delays from request to data delivery. With this method, the people on site can acquire the data on the spot.

The operation is also simple. For example, with LRTK, attach the terminal to the smartphone, press “Start Scan” in the app, and then simply walk around the site pointing the camera. By taking multiple photos while walking, the smartphone’s camera and LiDAR capture the surrounding 3D shapes, which are automatically converted into point cloud data. No special tripod setup or complicated configuration is required, and untrained workers can obtain detailed 3D site data in a matter of minutes, as has been demonstrated. There are actual reports of workers using the system proficiently without prior specialized training.

Moreover, ground-based walking scans excel in environments where drones struggle. For instance, under bridges, inside tunnels, in densely wooded forests, under elevated structures, or in narrow urban spaces—where drone flights are difficult—smartphone surveying is possible wherever a person can walk. On windy or rainy days when drones cannot fly, ground scanning is less affected by weather (with due safety precautions, scanning while holding an umbrella is even possible). By not relying on drones, surveying timing is no longer constrained by weather or aviation regulations, enabling flexible, immediate data acquisition when needed.

現場で即時に体積・面積計算、スピーディーな意思決定

The value of 3D point cloud data lies in being able to measure quantities and shapes on site. Point cloud data acquired with a GNSS terminal + smartphone can be utilized much more quickly than before. For example, at an earthwork site where you want to know the volume of fill or excavation, having point cloud data allows on-site instantaneous volume calculations. LRTK’s system can access point clouds on the cloud from a smartphone or tablet and automatically calculate fill or backfill volumes simply by selecting the area of interest. For paving work, the asphalt area and thickness distribution can be analyzed from the point cloud to evaluate the finish on the spot.

Previously, survey data had to be taken back to the office for CAD drawing or Excel volume calculations, which took time. If point clouds can be used immediately on site, you can judge construction quality the same day and proceed to corrective work. For example, areas with insufficient pavement thickness or inadequate excavation depth are immediately obvious in automatically generated heat maps (difference maps) from point clouds. If defects are found, you can perform additional work or corrections on the spot and re-scan to confirm, establishing a daily cycle of measure→fix→confirm. This minimizes rework during construction, speeding up site decision-making while ensuring quality.

クラウド連携で実現するデータ共有とAR活用

Point cloud data acquired with a GNSS terminal + smartphone can be synced to the cloud with one touch. For example, with LRTK, acquired data can be uploaded to a dedicated cloud with a single button in the app. On the cloud side, automatic point cloud generation from photos (SfM technology) and integration processing of LiDAR scan data are performed, including optimization like noise removal. Furthermore, pre-uploaded design data (final 3D models or design cross-sections) can be compared with measured point clouds, and with just a few clicks you can produce color-coded heat maps and numeric tables showing construction deviations. Site personnel do not need to be aware of this sequence of analysis—the automated cloud service performs these tasks in the background, greatly reducing data processing burdens.

Cloud-synced data can be viewed and used from anywhere on any device with internet access. Point clouds scanned on site and generated heat maps can be immediately reviewed by managers or clients on office PCs for real-time sharing. By issuing a share link, subcontractors or clients without specialized software can view 3D data via a browser. There is no need to prepare expensive workstation PCs or dedicated viewers at each location; centralized cloud management allows all stakeholders to easily handle the data.

Moreover, cloud-processed and compared data can be used for AR (augmented reality) display. By downloading point clouds or heat maps to a smartphone or tablet and overlaying them on the camera view, you can project measurement results into the real world. For example, AR display of as-built heat maps allows you to visually inspect where excesses or shortages exist at the construction site. Defective areas that previously required marking on the ground can be intuitively located on the screen for immediate repair. You can also overlay the design completion model (BIM/CIM data) on the site to visually compare progress. AR can even be used to “see through” to invisible underground structures such as buried pipes—if you scan buried piping when installed, anyone can later check its buried position and depth through an iPhone, helping prevent damage accidents during future excavations.

By leveraging cloud and AR, point cloud measurement becomes more than data acquisition; it enables a new construction management workflow where the digital and the physical site are seamlessly connected. The cycle of acquisition → analysis → sharing → on-site feedback dramatically streamlines as-built management and progress control.

LRTKが実現するオールインワン測量システム

Now, as a concrete solution that enables everything from point cloud measurement to cloud utilization and AR, let’s summarize the functions of LRTK. LRTK is an integrated system composed of compact GNSS terminal hardware, a smartphone app, and cloud services, offering all the functions necessary for site surveying in an all-in-one package. Its main features are as follows.

• Point cloud scanning: The iPhone or iPad’s LiDAR sensor and camera scan the site to acquire high-density 3D point cloud data. With LRTK, even large sites can be quickly point-clouded in detail, capturing elements such as rebar and slope shapes. Because the point clouds have high-precision absolute coordinates from GNSS, they are of quality suitable for as-built management results in accordance with the Ministry of Land, Infrastructure, Transport and Tourism standards.

• Geotagged photos: This function automatically records the shooting coordinates and camera orientation on photos taken with the smartphone. It prevents confusion like “Where was this photo taken?” and allows later photo verification on a map. Photos of buried structures or reinforcement saved to the cloud with coordinates increase evidentiary reliability.

• Coordinate navigation (layout/marking): A navigation function that guides you on the smartphone screen to target coordinates such as points on design drawings or stakeout positions. Anyone can walk the site with a smartphone and, when approaching the specified coordinate, receive on-screen guidance to pinpoint the exact location. It’s useful for finding reference points buried by vegetation or snow. Layout tasks that used to require surveying instruments can now be done by a single person.

• AR display: Acquire point clouds or design 3D models and overlay them on the real-world view. Thanks to LRTK’s high-precision positioning, virtual objects remain stably aligned with real positions even after moving several meters, providing a reliable AR experience. You can project expected completion visuals on site to share visions with clients, or overlay design models during inspections to check for discrepancies. The application range is vast.

• Cloud sharing and analysis: By syncing data to the LRTK cloud, automatic processing, analysis, and stakeholder sharing of point clouds can be done with one click. No dedicated software installation is required; sending a share link allows anyone to view 3D data in a browser. Convenient cloud analysis tools like automatic cross-section generation and report output are provided, enabling seamless data use between site and office. In offline environments, models compatible with Japan’s quasi-zenith satellite “Michibiki” centimeter-level augmentation service (CLAS) (cm level accuracy (half-inch accuracy)) can perform high-precision positioning even outside network coverage.

Thus, LRTK is designed to complete the entire process of positioning, measurement, recording, sharing, and utilization with a single smartphone. It thoroughly simplifies on-site operations while providing data that surpasses conventional methods in both accuracy and comprehensiveness. It truly represents a next-generation “universal surveying system” combining a smartphone and a GNSS terminal.

LRTKによる簡易測量のメリットまとめ

Finally, let’s summarize the benefits of introducing simple 3D surveying using a GNSS terminal + smartphone.

• Low cost and labor savings: You can reduce costs of purchasing drones or large equipment or outsourcing, and perform 3D surveying with just a palm-sized GNSS terminal and a smartphone. There is no need to carry or install heavy equipment, reducing the burden of on-site work.

• Rapid data acquisition: Surveying can be done the moment you decide, and point cloud data can be obtained on the same day. Construction no longer stalls waiting for surveys, enabling timely decisions aligned with progress.

• High precision and reliable results: RTK-GNSS delivers centimeter-level positional accuracy, and acquired point clouds have absolute coordinates enabling accuracy verification. They can meet the accuracy requirements of the Ministry of Land, Infrastructure, Transport and Tourism’s as-built management guidelines, allowing use as official as-built results.

• Promotion of on-site DX: Combining cloud and AR tightly links digital data and field work. Photos, point clouds, and design models are centrally managed and can be shared and visualized by all stakeholders, reducing communication loss and human error.

• Improved safety and flexibility: Measurements of hazardous areas can be done safely and remotely, and surveying is possible in environments where drones cannot fly. AR visualization of buried objects helps reduce accident risks during excavation, contributing to safety management.

In this way, point cloud measurement solutions using GNSS terminals and smartphones (e.g., LRTK) combine unprecedented ease of use with high precision, dramatically improving productivity and quality control on site. The slogan “Realizing 3D surveying without drones” is not an exaggeration—this new method is already proving effective at many sites. If your company faces challenges in construction management or surveying operations, consider experiencing this GNSS terminal-driven point cloud measurement revolution. As a first step in on-site DX, 3D surveying anyone can do will surely become a powerful asset.