LRTK Drone × Cloud Streamlines Work! High-Precision Point Cloud Generation That Transforms the Field

Table of Contents

• Introduction

• What Is Point Cloud Generation by Drone

• Why Drone Surveying Reduces Labor

• Expanded Efficiency with Cloud Use

• High-Precision Point Clouds Achieved with RTK

• How Point Cloud Data Changes the Field

• Labor-Saving High-Precision Surveying with LRTK Drones

• FAQ

Introduction

In the construction and civil engineering industries, the aging of skilled technicians and labor shortages have become serious issues, making labor-saving and efficiency major challenges. One technology attracting attention in this context is 3D surveying using drones (unmanned aerial vehicles). By photographing a site from the air with a drone and creating detailed 3D models called point clouds, you can grasp large-scale terrain and structures in a short time.

However, obtaining high-precision data requires improved position accuracy and large-scale data processing, which have been barriers to adoption. The key technologies here are RTK (Real Time Kinematic) for high-precision positioning and the use of cloud computing. By combining drones with the cloud, it is possible to achieve both labor savings and high precision—previously difficult to reconcile—and this is bringing transformation to site surveying and construction management.

This article explains the basics of point cloud generation by drones, the benefits, cloud utilization, high-precision technologies, and how point cloud data is changing the field. We also introduce how anyone can easily achieve high-precision surveying using the latest solution, the LRTK drone.

What Is Point Cloud Generation by Drone

Point cloud data is 3D data that represents the surfaces of objects and terrain as countless points. Traditionally, acquiring point clouds commonly involved detailed measurements with ground-based laser scanners. However, with drones you can photograph wide areas from the air at once and convert them into point clouds, enabling efficient acquisition of 3D data in a short time.

There are mainly two methods for point cloud generation by drone. One is photogrammetry, where a camera mounted on the drone takes many photos and reconstructs the 3D shape from overlapping images to generate a point cloud model. The other is mounting a laser scanner (LiDAR) on the drone to directly obtain a point cloud by calculating distances from the time of flight of laser pulses. In either method, you obtain a high-density collection of points covering the ground and structures, which becomes the point cloud data.

The advantages of drone-based point cloud generation are that you can cover wide areas in a short time and safely measure hazardous or hard-to-access locations from above. For example, aerial photography of a development site spanning several hectares or a large structure can yield millions of 3D points in just a few tens of minutes of flight. In this way, drones serve as “point cloud generation machines” that collect large numbers of survey points in a short time and provide detailed information that could not be obtained by traditional ground surveying. Point cloud data is beginning to be used in a wide range of applications such as creation of civil survey maps, calculation of earthwork volumes, and maintenance management of structures.

Why Drone Surveying Reduces Labor

Introducing drones dramatically reduces the labor and time previously required for surveying work. Traditionally, ground surveying often involved a team of two to three or more people setting up a total station and measuring points one by one with a staff. On large sites it was difficult to measure every point, and surveys tended to be sampling of key locations only.

In contrast, with drone surveying a single operator can set the drone to fly automatically and perform hundreds to thousands of measurements simultaneously. For example, a survey that previously took several people a whole day can often be completed in several tens of minutes with a drone. The number of obtained points increases dramatically, reducing rework due to missed measurements.

Furthermore, because measurements are non-contact, there is a major safety advantage in that people do not need to enter steep slopes or areas with poor footing. Drone surveying can cover wide areas with few people, helping to alleviate labor shortages on site. Also, automatic flight and aerial photography are relatively easy to learn, so even if experienced survey technicians are scarce, younger staff can use drones effectively. Where work previously had to be partially suspended for surveying, drones can complete surveys quickly, minimizing impact on construction.

Expanded Efficiency with Cloud Use

After obtaining large numbers of photos with a drone, processing (point cloud generation and analysis) traditionally required high-performance PCs and specialized software. Generating a 3D model from hundreds of photos can take hours or even tens of hours of computation, which was a significant burden for site personnel.

Recently, however, services have emerged that perform processing of such large datasets on internet servers (the cloud). Using the cloud, site operators can simply upload captured images from a laptop, and the server will automatically execute point cloud generation. During this time, personnel can perform other tasks or wait for the completed data. There is no need to prepare expensive workstations or master complex software operations.

Moreover, the generated point cloud data and orthophotos (orthorectified images created by stitching aerial photos) are stored in the cloud, so you won’t worry about running out of storage and can view them anytime, anywhere. Sharing data with stakeholders is easy, and point clouds can be inspected and measured via a web browser without installing a dedicated viewer. Where necessary, georeferencing using known control points can also be performed easily in the cloud to improve absolute coordinate accuracy.

By leveraging the cloud in this way, the entire workflow from point cloud generation to result sharing can be performed in a one-stop manner, dramatically improving overall surveying efficiency. With data always in the cloud, all stakeholders can access the latest information, enabling smooth information sharing between the field and the office. Even if a PC fails, cloud backups reduce the risk of data loss.

High-Precision Point Clouds Achieved with RTK

RTK (Real Time Kinematic) is a technology that improves positioning accuracy by correcting GNSS (satellite positioning) errors. A base station installed at a reference point and a rover (such as a drone-mounted receiver) receive satellite signals simultaneously, and the base station sends error information to the rover via radio or network to correct errors, reducing positioning errors to several centimeters. Ordinary GPS typically has errors of about 5–10 m (16.4–32.8 ft), but with RTK this can be reduced to within several centimeters (several inches).

In Japan, a network-type RTK (VRS method) that utilizes national control points and private correction services has become widespread so that dedicated base stations need not be installed. Also, by using the centimer-level positioning augmentation service (CLAS) provided by the quasi-zenith satellite Michibiki, high-precision positioning is possible even in mountainous areas without cellular coverage. Whereas dedicated equipment and radio systems used to be expensive, recent miniaturization and cost reduction of receivers and improvements in apps have made RTK easier to adopt. As a result, environments where centimeter-level RTK positioning can be easily performed on site are now in place.

Combining RTK with drone surveying allows accurate absolute coordinates to be attached to captured photos and point cloud data. By aligning generated point cloud models with map coordinate systems, they can be easily overlaid with other survey data and design drawings. Even non-RTK-equipped aircraft can achieve similar accuracy by installing known coordinate markers (control points) on site and aligning the point cloud in post-processing.

In practice, positioning accuracy using RTK is on the order of ±2–3 cm (±0.8–1.2 in) horizontally and ±3–5 cm (±1.2–2.0 in) vertically, which more than satisfies the tolerances required for typical civil engineering construction quality control. With high-precision point clouds, accurate calculations of fill and cut volumes and verification of as-built conditions can be performed, producing data quality acceptable for public surveying outcomes. RTK technology is therefore a critical element that dramatically enhances the practicality of drone-based point cloud surveying.

How Point Cloud Data Changes the Field

High-density point cloud data obtained in this way brings significant changes to site construction management and inspection work. First, quality control accuracy improves dramatically. 3D point clouds record even subtle irregularities of terrain and structures, allowing you to detect deviations that conventional spot measurements would have missed.

By overlaying design data with the as-built point cloud, you can intuitively visualize where things match design and where there are excesses or shortages using color-coding, enabling early detection of areas needing rework. It is also powerful for earthwork management. Comparing the completed 3D point cloud with the planned design terrain allows immediate calculation of fill and cut volumes, enabling volume calculations on the order of thousands of cubic meters to be completed instantly. Quantity estimation tasks that used to involve measuring widths and heights section by section and manually calculating totals will be greatly streamlined.

Additionally, arbitrary cross-sections and plan views can be created from the acquired point cloud, eliminating the risk of being unable to draft drawings due to missed measurements. Once data is obtained, you can extract the necessary sections or plans later for analysis, removing concerns about “forgetting to measure part of the site” during inspection.

On-site as-built management and quality inspection historically relied heavily on experience and intuition, making comprehensive coverage difficult. But by fully leveraging point cloud data, anyone can grasp conditions objectively with numerical and visual information and make rapid decisions. The Ministry of Land, Infrastructure, Transport and Tourism is promoting the use of 3D survey data through initiatives such as *i-Construction*, and 3D point cloud–based as-built management is becoming an industry standard. In fact, sites that introduced ICT construction reported average manpower reductions of over 30%, demonstrating the clear productivity gains of digitalization.

Point cloud data is also useful for post-construction maintenance. By periodically conducting drone surveys and comparing new point clouds with historical data, you can monitor terrain changes and structural displacement to detect deterioration and anomalies early. In this way, point cloud utilization fundamentally transforms site work processes and enables superior construction management and inspection in both accuracy and efficiency.

Labor-Saving High-Precision Surveying with LRTK Drones

Finally, as a concrete solution that integrates the drone surveying and cloud utilization discussed so far, we introduce the LRTK drone. LRTK drone is a Japan-origin cloud-based point cloud generation service that combines high-precision positioning technology with proprietary point cloud generation algorithms to automatically generate point cloud models with absolute coordinates simply by uploading photos taken by a drone.

There is no need to install expensive dedicated software on your PC; processing starts with the simple operation of specifying an image folder on the web. It can handle large-scale sites; for example, even for 100 m (328.1 ft)-class slopes or large dams, point cloud generation on the cloud can be completed in about 1 hour.

The generated point cloud can be displayed in a 3D viewer on the LRTK cloud, and analyses such as dimension measurement, slope checking, and earthwork calculation can be performed on the spot. Orthophotos (composite overhead images) are also generated automatically and can be used as high-resolution maps. Additionally, if you upload design drawings to the cloud, the system can automatically detect and color-code deviations by comparing them with the as-built point cloud. You can immediately see whether construction locations conform to design and efficiently proceed with corrections to pass inspections. As needed, arbitrary cross-sections can be created from the point cloud and downloaded in DXF format, allowing drafting to be completed entirely in the cloud.

The LRTK series also includes a simple surveying device using a smartphone, the “LRTK Phone,” which allows people to walk and acquire point clouds in blind spots that are difficult for drones to capture. Point cloud data acquired by drone and those acquired by smartphone both have high-precision coordinates, so they are automatically merged in the cloud and treated as a single 3D model.

Moreover, because LRTK drone is a domestic manufacturer’s service, you can receive thorough support from introduction through operation, which provides peace of mind. Even those trying drone surveying for the first time can start smoothly with the follow-up of specialized staff. By using LRTK drone, complex 3D surveying becomes dramatically simpler, enabling high-precision point cloud–based site management with a small team. Experience how this drone × cloud solution streamlines surveying with high-precision point cloud generation and transforms your field.

FAQ

Q: What does it mean to generate a point cloud with a drone? A: It means reconstructing a site’s 3D shape as a collection of countless points (a point cloud) by aerial photography using a camera or LiDAR mounted on a drone. Terrain can be reconstructed in 3D from aerial photos, or distances to targets can be measured by laser to digitally record the ground and structures as a high-density assemblage of points. Using these 3D point cloud data, you can grasp site dimensions and shapes in detail.

Q: How accurate is drone surveying? A: With appropriate use of RTK or control points, errors can be kept to several centimeters (several inches) horizontally and to under 5 cm (under 2.0 in) vertically. Ordinary GPS alone can produce errors of several meters, but with high-precision position correction you can achieve accuracy comparable to conventional ground surveying. For formal as-built inspections, accuracy control using control points is recommended, but under good conditions an RTK-equipped drone alone can provide practically sufficient accuracy.

Q: What is RTK? A: RTK (Real Time Kinematic) is a technique to greatly improve satellite positioning accuracy. Correction information from a base station is sent to a rover (such as a drone), reducing GPS positioning errors to a few centimeters. This allows high-precision position coordinates to be attached to data acquired by drones and surveying instruments.

Q: What are the benefits of processing in the cloud? A: Benefits include the ability to process large numbers of photos without arranging high-performance PCs and sharing results on the web without dedicated software. With cloud processing, you simply upload photos from the field and point cloud generation runs automatically while you attend to other work. Generated data are stored in the cloud, so you do not have to worry about large storage capacity, and stakeholders can easily view and utilize 3D data via shared links.

Q: Do I need expensive equipment or special PCs? A: No. Basically, you can introduce the system with a common commercial drone (for aerial photography) and a PC with internet access. For cases requiring higher accuracy, RTK-capable drones or GNSS base stations are ideal, but accuracy can also be ensured by installing a few control points if those are not available. Using cloud services means you do not need expensive workstations or dedicated software.

Q: Can people without specialized knowledge handle it? A: Yes. Flight routes can be set with automatic flight apps, so complex piloting is unnecessary. Data processing is automated on the cloud side, so users only need to upload captured images. Once basic procedures are learned, even those with limited surveying experience can obtain high-quality 3D data. Using services with established support systems allows worry-free introduction for first-time users.

Q: What if a drone cannot be flown in certain places or situations? A: If drone flight is difficult due to regulations or environmental factors, data collection from the ground is an option. For example, LRTK provides a handheld surveying device using a smartphone (LRTK Phone) that allows walking to acquire point clouds. Since RTK can provide high-precision coordinates, drone-acquired and smartphone-acquired point clouds can be integrated without misalignment. Areas where drones cannot be used can be supplemented by such ground surveys to obtain seamless 3D data.

Q: What should I pay attention to when introducing drone surveying? A: Compliance with laws and ensuring safety are essential for drone flights. For instance, under aviation law you must confirm restricted airspaces, night flight regulations, and obtain necessary flight permissions and approvals. Also note that flights are difficult in strong winds or rain, so weather conditions should be considered. If these conditions are met and operations are planned properly, drone surveying can deliver its full benefits.