What is LRTK LiDAR Point Cloud? Summary of Mechanism, Accuracy, and Introduction Benefits for Beginners

Table of Contents

• What is LRTK LiDAR point cloud?

• Basic knowledge of LiDAR sensors and point clouds

• Integration of LRTK and LiDAR point clouds

• How to think about the accuracy of LRTK LiDAR point clouds

• Points that make it easy for beginners to use

• Applications to AR and overlaying drawings

• Use cases such as cloud sharing

• Introduction effects: accuracy, speed, visualization

• Advantages of simple surveying with LRTK and recommendations for adoption

• Frequently Asked Questions (FAQ)

What is LRTK LiDAR point cloud?

An LRTK LiDAR point cloud is high-precision three-dimensional point cloud data obtained by combining 3D scanning with a LiDAR sensor and the high-precision positioning technology LRTK. LiDAR (Light Detection and Ranging) is a sensor that uses laser light to measure the distance to a target, and its measurement results are represented as a collection of countless points (a point cloud). Traditionally, acquiring accurate point clouds required expensive equipment such as dedicated 3D laser scanners. However, with LRTK LiDAR, you can perform similar point cloud measurements easily using only a smartphone such as an iPhone and a small device.

LRTK is our high-precision GNSS solution that realizes real-time kinematic (RTK) satellite positioning on a smartphone. By scanning the surroundings with the smartphone’s built-in LiDAR while combining centimeter-class position information obtained by the LRTK device, you obtain a point cloud in which each point is assigned precise coordinates such as latitude, longitude, and elevation. In other words, using LRTK LiDAR point clouds lets a single person easily record site geometry as high-precision 3D data. This article explains the mechanism, accuracy, and benefits of introducing this technology in an easy-to-understand way for beginners.

Basic knowledge of LiDAR sensors and point clouds

A LiDAR sensor irradiates laser light onto an object and measures distance from the time it takes for the reflected light to return. For example, a smartphone LiDAR emits infrared laser pulses and rapidly measures the time until they bounce back from walls, floors, and so on. By this principle, LiDAR can acquire hundreds of thousands of distance data points per second and record them as a collection of points in three-dimensional space. This multitude of points is called a point cloud, and looking at point cloud data you can see the shape of the real space reproduced as a cluster of points.

Each point in point cloud data has XYZ coordinates and can accurately represent the shape and size of objects. Unlike photographs, point clouds allow you to measure dimensions at arbitrary locations afterward or create cross-sections. For this reason, point clouds are used in surveying and construction for recording terrain, construction management, and as-built verification, and in recent years they have attracted attention in trends such as digital twins and i-Construction. While terrestrial laser scanners and drone-mounted LiDAR were mainstream in the past, LiDAR sensors are now installed in mobile devices such as iPhones and iPads, enabling easy acquisition of surrounding 3D point clouds.

Integration of LRTK and LiDAR point clouds

Although 3D scanning is possible with smartphone LiDAR alone, the point cloud obtained is recorded in the device’s relative coordinate system and thus is offset from real-world map coordinates. The integration of LRTK and LiDAR solves this. By using the high-precision position information (latitude, longitude, elevation) obtained from the LRTK device, the smartphone continuously knows its precise position during scanning. The acquired point cloud is assigned accurate GNSS-derived coordinates in real time, allowing the point cloud to be placed in the correct location on a site coordinate system or map.

In other words, LRTK acts as a positional reference point and links the LiDAR point cloud to real-world coordinates. Traditionally, to align point clouds with maps you needed to set known points in the field and perform manual alignment later. With LRTK LiDAR, that work is unnecessary, and from the moment of scanning the point cloud is placed directly on the surveying coordinate system. Data is stored in Japan’s plane rectangular coordinate system (surveying coordinates) and can be converted immediately to WGS84 or any local coordinate system as needed. By combining LRTK and LiDAR, the workflow from point cloud acquisition to reflection in drawings and maps becomes seamless.

How to think about the accuracy of LRTK LiDAR point clouds

One of the features of LRTK LiDAR point clouds is their high positioning accuracy. While the position accuracy of general smartphone GPS is about 5–10 m (16.4–32.8 ft), LRTK achieves errors of approximately ±1–2 cm (±0.4–0.8 in) horizontally and ±3 cm (±1.2 in) vertically. This dramatic improvement is because the LRTK device uses signals from multiple satellites and correction signals to eliminate error factors. In practice, comparisons between positions measured by LRTK Phone and high-end surveying GNSS receivers showed differences of only a few millimeters, confirming accuracy comparable to professional equipment.

Meanwhile, the LiDAR sensor’s own measurement accuracy is also high, within a few centimeters at close range. The iPhone LiDAR has an effective range of a few meters, but within that range it can capture wall surface irregularities and ground elevation to the level of a few centimeters. Because LRTK LiDAR point clouds combine the shape measurement accuracy of LiDAR with the positioning accuracy of GNSS, site objects can be digitized in 3D with nearly true-to-life accuracy. Elevation differences of terrain and structure heights can also be acquired accurately, making the previously difficult vertical positioning easy. There have been cases where positioning succeeded even in mountainous areas without an open sky, and optimization according to the environment ensures stable accuracy. However, note that positioning is difficult in places where satellite signals cannot reach, such as inside tunnels.

Points that make it easy for beginners to use

• Simple operation: Dedicated smartphone apps have intuitive UIs, and starting positioning or point cloud scanning can be done with a single button. Complex settings and calculations are processed in the background, so beginners without surveying expertise can handle it easily.

• Compact equipment: The LRTK Phone device weighs about 165 g and is about 1 cm (0.4 in) thick, allowing it to be attached to a smartphone in a compact size. Traditional tripods and large equipment are unnecessary; only a smartphone and a small device make transport easy. It is mobile even in narrow sites or at heights, allowing surveying to start immediately when needed.

• One-person operation: While traditional surveying sometimes required an assistant, LRTK LiDAR point clouds allow one person to complete all tasks. Simply hold the smartphone or attach it to a monopod (pole) and measure to obtain coordinate-tagged point cloud data on the spot. It is highly effective at sites with labor shortages or small teams.

• Automated data processing: Post-measurement point cloud merging, coordinate conversion, cloud storage, and other tedious data processing are automated. Once measurement is finished you can check results in the app, eliminating the need for complex post-processing back in the office. Acquired data can be shared to the cloud on site or exported for CAD software as needed.

• Safe and secure: Easy operation reduces confusion on site, so even first-time users can use it with confidence. In hazardous slopes or disaster sites, point clouds can be obtained from a safe distance, enabling less experienced technicians to carry out measurements without undue risk.

• Affordable to introduce: The LRTK solution greatly reduces initial cost compared to expensive surveying instruments. If you already have a supported smartphone, you only need a small device and software to get started. The low initial investment makes it easy for individuals and small to medium-sized businesses to adopt.

Applications to AR and overlaying drawings

High-precision data obtained by LRTK LiDAR point clouds is powerful for on-site verification when combined with AR (augmented reality) technology. Through the smartphone screen, virtual 3D models or guidelines can be overlaid on the actual view, allowing intuitive understanding of where and at what elevation a designed structure will be on site. Thanks to LRTK’s high-precision coordinates, there is no need for pre-alignment of models, and models are projected precisely in their intended positions without shifting. For example, you can display a building model in AR to confirm the completed image, or show virtual lines on the ground to indicate excavation areas.

Furthermore, using LRTK’s position guidance function makes stake-out work (layout) easy. If you input coordinates of reference points from the drawings, targets or arrows appear in AR, and workers can reach the exact stake locations by following the on-screen directions. Without the need to track angles and distances with surveying instruments or measure with tapes as in the past, intuitive on-screen guidance enables shorter work times and reduces human error.

The acquired point cloud data can also be used for overlaying with drawings and for drafting. Import point clouds into the LRTK cloud or CAD software to compare design drawings and measured point clouds on the same coordinates. For example, overlay the as-built point cloud on the design model to check for discrepancies, or create plan and cross-sectional drawings from terrain point clouds. The LRTK system also offers functions that automatically extract terrain contour lines from point clouds to generate drawings, enabling quick drafting from on-site data. This bridges the gap between point clouds and traditional 2D drawings and streamlines design-construction consistency checks.

Use cases such as cloud sharing

LRTK LiDAR point clouds support cloud sharing, enabling smooth use of acquired data both inside and outside an organization. Point cloud data, survey points, and photos uploaded from the smartphone on site are saved and shared to the cloud via the internet immediately. Accessing via a browser from an office PC allows viewing 3D point clouds without installing dedicated software. In the cloud you can rotate and zoom point clouds while measuring distances and areas, and combine photos to understand the situation. Because all stakeholders can view the same latest data, information transfer between the field and office is greatly improved.

For example, if a field staff member conducts a survey with LRTK LiDAR point clouds and syncs the data to the cloud, managers and designers in a remote office can instantly view the 3D data, measure dimensions, and compare with design drawings as needed. This allows accurate situation assessment and decision-making without traveling to the site, speeding up decision cycles. In fact, municipal governments have used LRTK’s cloud sharing for disaster response. For instance, during the Noto Peninsula earthquake, quickly recording affected sites in 3D and sharing them on the cloud enabled remote stakeholders to grasp damage details and accelerate restoration planning. From daily construction management to emergency damage surveys, cloud integration enhances the value of LRTK LiDAR point clouds.

Introduction effects: accuracy, speed, visualization

Introducing LRTK LiDAR point clouds brings major benefits in terms of accuracy, speed, and visualization as follows.

• Improved accuracy: Centimeter-class high-precision data minimizes previously overlooked offsets and errors. With accurate coordinate data for comparisons with design values and as-built inspections, construction mistakes can be detected and corrected early. Vertical verification, which was difficult before, also becomes easier, improving quality control. By acquiring point cloud data, you also avoid the risk of discovering missed measurement points later, ensuring complete and reliable records.

• Speed-up: Time and effort required for surveying and measurement are greatly reduced. Point cloud measurement, which acquires many points at once, can reduce site measurement that previously took hours to a matter of tens of minutes. Time spent on equipment setup and reading points is reduced, allowing fast one-person site rounds. Because data is shared to the cloud immediately after acquisition, reporting to the office and drafting can proceed quickly. Overall, lead time from investigation to decision is shortened, improving project-wide efficiency.

• Visualization benefits: Because the site situation is intuitively visualized with 3D data and AR, information sharing and consensus-building among stakeholders is smoother. For example, terrain undulations that are hard to convey orally or on 2D drawings become obvious when viewing a 3D model from point clouds. Showing the completed image via AR makes it easier to gain understanding from clients and local residents. Visual comparisons also help detect discrepancies between design and construction early, preventing rework. Such visualized data facilitates communication and ultimately improves project quality.

Advantages of simple surveying with LRTK and recommendations for adoption

LRTK LiDAR point clouds transform surveying work that previously relied on specialists into simple surveying that anyone can perform. The ease of achieving high-precision 3D measurements with a single smartphone strongly promotes digital transformation (DX) on site. Adoption is advancing across a wide range of fields from local governments to construction companies, producing results in disaster response, infrastructure maintenance, urban planning, and more.

Compared to traditional methods, LRTK LiDAR point clouds offer overwhelming efficiency and versatility and are likely to become the standard surveying method of the future. The benefits of accuracy, speed, and visualization improve work quality and productivity, reduce site burden, and help address labor shortages. If you feel challenges in site surveying efficiency or 3D data utilization, consider adopting LRTK LiDAR point clouds. You will likely be surprised by their ease and effectiveness. Embrace the latest technology and update your field operations.

Frequently Asked Questions (FAQ)

Q: What is an LRTK LiDAR point cloud? A: It is three-dimensional surveying data that combines point cloud data acquired by a smartphone LiDAR sensor with high-precision GPS (LRTK) position information. Since the point cloud measured by the smartphone’s laser is assigned coordinates with cm level accuracy (half-inch accuracy), it can be used directly for precise site measurement and recording.

Q: What do I need to use it? A: You need an iPhone or iPad equipped with a LiDAR sensor and a dedicated small GNSS receiver called LRTK Phone. Install the dedicated LRTK app on these devices to use them. Positioning can basically be done without network connectivity, but a network-enabled environment is convenient for cloud sync and map display. For more stable measurements, fixing the smartphone to a monopod (pole) is ideal, but handheld use is also possible.

Q: Can it be used outside mobile phone coverage? A: Yes. LRTK supports the centimeter-level positioning augmentation service (CLAS) provided by Japan’s Quasi-Zenith Satellite System “Michibiki,” allowing high-precision positioning based solely on satellite augmentation signals even in mountainous areas without mobile connectivity. However, note that positioning is not possible in underground or tunnel environments where GPS satellite signals themselves cannot be received.

Q: Can it be used without surveying expertise? A: Yes. The system is designed for intuitive operation. Simply press “Start positioning” or “Start scan” on the smartphone app and point cloud acquisition and coordinate calculation are performed automatically. Complex settings and calculations are handled by the system, so users only need to follow on-screen instructions. Operation manuals and support are also provided, so beginners can use it with confidence.

Q: What applications and fields can it be used for? A: There are wide-ranging applications such as as-built management on construction sites, layout stamping for foundations, quantity calculations for civil engineering (volume calculation for embankment/excavation), disaster damage recording, and infrastructure maintenance (road sinkhole checks, bridge displacement measurements). In short, LRTK LiDAR point clouds are highly useful whenever accurate recording and sharing of site shape and position are required. Adoption is progressing in surveying, civil engineering, architecture, urban planning, agriculture and forestry, and disaster prevention fields.

Q: How does it differ from traditional surveying methods? A: Traditionally, measurements were taken point by point with a total station, or GPS yielded meter-level errors. LRTK LiDAR point clouds acquire a large number of points quickly and with high precision in one go. There is no need to carry heavy tripods or prisms; surveying can be completed with just a smartphone and a small device. Because the results are immediately available as 3D data, post-processing is reduced and the data can be used right away for stakeholder presentations. In short, it offers a different level of efficiency in “speed,” “accuracy,” and “amount of information” obtained from the same surveying work.

Q: Can drawings be created from point cloud data? A: Yes. Point cloud data acquired with LRTK can be exported in common point cloud file formats and imported into CAD/BIM software such as AutoCAD and Revit for drawings and model creation. The LRTK cloud also provides functions such as cutting cross-sections and automatically extracting terrain contour lines to generate DXF drawings. In other words, having point clouds enables smooth creation of traditional plans and cross-sections, improving efficiency in design and report preparation.