Easily Obtain High-Precision Point Cloud Data Aligned to Public Coordinate Systems: LRTK Sets a New Standard for Surveying Accuracy

Table of Contents

• Introduction

• Easy 3D Point Cloud Measurement Anyone Can Do with Smartphone LiDAR

• Centimeter-Level Positioning Accuracy Achieved with LRTK

• The Significance of Assigning Public Coordinates and the Importance of Ensuring Accuracy

• Point Cloud Use Cases: Volume Calculation and Comparison with Design Data

• Conclusion: Recommend Simple Surveying with LRTK

• Frequently Asked Questions

Introduction

In construction and civil engineering sites, the DX (digital transformation) of operations using 3D point cloud data has been accelerating in recent years. Point cloud data, which can record a site in three dimensions, is a valuable information resource that supports a wide range of tasks from design to construction management and as-built inspection. However, traditionally, conducting such high-precision 3D scans required specialized laser scanners or surveying equipment, and operation demanded advanced skills.

Amid this, a newly noticed measurement method combines smartphone or tablet LiDAR sensors with RTK positioning. Recent smartphones (e.g., higher-end iPhone and iPad models) include compact LiDAR, and with dedicated apps anyone can easily capture point cloud data of their surroundings. By leveraging position information from LRTK (a centimeter-level positioning solution), captured point clouds can be assigned public coordinates, achieving surprisingly high positional accuracy. In short, “anyone” can now perform “on-the-spot” high-precision 3D scans.

This article introduces 3D point cloud measurement using smartphone LiDAR × LRTK as the latest solution for easily obtaining high-precision point cloud data aligned to public coordinate systems. We will explain concrete workflows from how to acquire point clouds with a smartphone to how to use the resulting data (viewing in a viewer, converting to CAD drawings, conducting as-built checks, etc.), and we will address the significance of converting scans to public coordinates and the importance of ensuring accuracy. Finally, we will naturally touch on the convenience of the LRTK solution our company provides for simple surveying, hoping to encourage adoption at your sites.

Easy 3D Point Cloud Measurement Anyone Can Do with Smartphone LiDAR

Until now, obtaining high-precision 3D point cloud data generally meant using expensive laser scanners or dedicated surveying equipment costing in the millions of yen. However, today’s latest smartphones and tablets equipped with LiDAR sensors allow anyone to easily 3D-scan their surroundings. For example, iPhone models from the iPhone 12 Pro onward and recent iPad Pro models have built-in LiDAR; launching a dedicated point cloud capture app and walking while holding the device enables real-time capture of point clouds of surrounding structures and terrain.

Smartphone LiDAR scanning is highly appealing because it is intuitive and easy. You simply move the device as if shooting a video, so even those without experience operating special equipment can handle it. Heavy tripods and power supplies are unnecessary, and the operator can quickly scan needed areas while walking around the site, offering strong mobility. Captured point clouds are visualized on the app screen in real time, allowing immediate verification for missed areas. There is no need to bring data back for long processing like traditional photogrammetry; you can decide on-site whether you have captured sufficient point cloud coverage.

Of course, smartphone LiDAR has physical limitations. The sensor’s effective range is on the order of a few meters in radius, so covering a wide area in detail requires walking while scanning to cover it. On the flip side, this means that as long as a person can walk the area, continuous wide-area point cloud capture is possible. In practice, the latest point cloud capture apps use AR-based self-localization, enabling uninterrupted scans of, for example, an entire office building floor or slopes longer than 100 m (328.1 ft). By walking the key areas, a single person can cover somewhat large sites, flexibly meeting needs like “let’s measure this while we’re here,” which was difficult with conventional equipment.

Moreover, point clouds captured with smartphone LiDAR can be combined with photogrammetry to greatly expand their applicability. You can quickly acquire 3D point clouds with LiDAR while simultaneously recording photos with the phone’s camera, then later add color information to the point cloud or enhance detail resolution. Some dedicated apps offer “detailed point cloud scan” features that fuse LiDAR and photos to produce high-density, colorized point clouds. Thus, the flexibility of switching scan methods according to the situation with just one smartphone is another attractive advantage.

Centimeter-Level Positioning Accuracy Achieved with LRTK

Point clouds obtained with smartphone LiDAR are useful on their own for situational awareness and relative dimensioning. However, for practical professional use, absolute positional accuracy is critically important. Typical smartphone GPS positioning has errors on the order of 5–10 m (16.4–32.8 ft), making it difficult to use captured point clouds directly in plan drawings or reference coordinate systems. Enter LRTK, a high-precision GNSS positioning solution.

LRTK is our proprietary solution that brings real-time kinematic (RTK) GNSS positioning technology to smartphones in an easy-to-use form. RTK corrects satellite positioning errors by communicating measurement data between a base station and a rover, and it traditionally required specialized, expensive equipment. LRTK combines a small receiver that attaches to a smartphone with correction information delivered via the internet to pinpoint positions with errors within a few centimeters. For example, whereas normal smartphone GPS may have errors of about 5–10 m (16.4–32.8 ft), using LRTK can improve accuracy to approximately ±1–2 cm (±0.4–0.8 in) horizontally and ±3 cm (±1.2 in) vertically. This level of accuracy rivals that of conventional Class 1 GNSS surveying instruments while fitting in your pocket as a smartphone-sized setup.

When LRTK positioning information is integrated with point clouds captured on a smartphone, the entire point cloud can be assigned public coordinates (absolute coordinates). In other words, the captured point cloud is mapped to accurate positions and heights on public coordinate systems such as Japan’s plane rectangular coordinate system or the global geodetic system. This makes it substantially easier to overlay scanned 3D data onto CAD drawings or GIS maps later, or to integrate with other surveying data. Normally, aligning point clouds to known control points requires cumbersome georeferencing work after returning to the office, but with LRTK you can be thought of as completing georeferencing at the same time as measurement.

What matters is that high-precision positioning and point cloud capture are realized in a one-stop workflow. Using an LRTK-enabled smartphone app (such as our “LRTK Phone” app), you can perform end-to-end operations on a single smartphone—from point cloud capture to high-precision positioning and assignment of public coordinates. As a result, the environment for anyone to easily acquire public-coordinate-attached point cloud data (point clouds with high-precision coordinate information) is becoming established.

The Significance of Assigning Public Coordinates and the Importance of Ensuring Accuracy

As noted above, matching 3D point cloud data to public coordinate systems and ensuring positioning accuracy are key to practical use. Here we summarize the significance.

First, about public coordinates (absolute coordinates). In public surveying in Japan, results must generally be produced in coordinate systems defined by the government (plane rectangular coordinate systems based on the global geodetic system or latitude/longitude). Even if data is used only within a single site, it is desirable for it to be on a unified coordinate system when considering cross-checking multiple survey datasets or future connections with other works. Point clouds obtained as relative coordinates from a smartphone alone will require later matching and transformation to known points, increasing effort and error risk. However, if point clouds measured on-site with LRTK are assigned public coordinates, that data might be used directly as 3D survey deliverables for electronic submission without requiring base-point surveys or post-processing.

Also, when point clouds carry public coordinates, multiple point clouds can be integrated later with perfect alignment. Even if point clouds captured on different days are combined into a single large 3D model, having public coordinates in each dataset lets you join them like puzzle pieces without misalignment. These benefits are all enabled by LRTK’s centimeter-level positioning.

In short, ensuring “positional certainty” is indispensable for point cloud utilization, and LRTK is a rational and powerful means to achieve that. High-precision point cloud data with assigned public coordinates dramatically increases the value of field measurement data, directly contributing to reduced effort and improved quality in downstream processes.

Point Cloud Use Cases: Volume Calculation and Comparison with Design Data

One prominent use case for high-precision point cloud data aligned to public coordinate systems is volume calculation using point clouds. For example, accurately determining earthwork quantities for embankment and excavation is effectively done by 3D-scanning the terrain before and after work, acquiring point clouds for each, and calculating volumes from the differences. While earthwork volumes were traditionally estimated from limited survey points using average-section methods, using point cloud data enables highly accurate volume calculation that reflects the entire site topography. Especially when point clouds are assigned public coordinates via LRTK, datasets before and after construction can be easily overlaid within the same coordinate system, making difference-based volume calculations smoother. Cloud-based point cloud viewers also allow immediate measurement of fill or surplus material against arbitrary reference planes.

Another use case is comparison with design data and drawings. With public-coordinate-compatible point clouds, the spatial coordinate system matches that of CAD design models or BIM/CIM 3D data, allowing visual and quantitative verification of as-built conditions versus design. For instance, overlaying as-built point clouds on the design 3D model lets you color-code areas to check whether required fill heights have been reached or whether excessive excavation has occurred; you can also cut cross-sections from the point cloud and compare them with design section lines for inspection. Traditionally, comparing surveyed data with drawings required coordinate transformations and manual work on paper plans, but using point clouds that already share coordinates streamlines and advances such inspections.

Furthermore, point cloud data is useful beyond as-built control. For example, computing the volume of stockpiled soil or aggregates from point clouds enables precise estimates of truck loads for hauling and inventory management. Comparing point clouds from multiple time points supports construction progress monitoring and provides documentary evidence supporting measured quantities. Thus, coordinate-attached point cloud data serves as an information foundation bridging measurement with design and construction, and it is a powerful means to visualize quantities and discrepancies that were previously hard to grasp.

Conclusion: Recommend Simple Surveying with LRTK

The new point cloud measurement method combining smartphones and LRTK has the potential to revolutionize precision surveying that previously relied on specialists. Free yourself from expensive equipment and complex workflows—why not start with small sites and try smartphone + LRTK 3D simple surveying? You will likely be surprised by its ease and usefulness. Through our LRTK solution, we hope to contribute to improving efficiency and accuracy in your site operations. Experience the latest trends in high-precision 3D scanning on your site.

Frequently Asked Questions

Q1. What preparations and equipment are needed to use LRTK and smartphone LiDAR? A. Basically, you only need a *LiDAR-equipped iPhone or iPad* and our *LRTK Phone system* (high-precision GNSS receiver + dedicated app) to get started. LiDAR-equipped models include iPhone 12 Pro and later, and iPad Pro (4th generation and later). With an internet connection, you can receive LRTK correction information and perform positioning and point cloud capture. No special surveying qualifications or difficult settings are required—just follow the app guidance to prepare.

Q2. What level of accuracy can be achieved? Can a smartphone really be that accurate? A. Yes—under appropriate conditions you can expect *approximately ±1–2 cm (±0.4–0.8 in) horizontally and about ±3 cm (±1.2 in) in height*. This accuracy is comparable to conventional high-performance GNSS surveying instruments. While smartphone GPS alone may have errors of about 5–10 m (16.4–32.8 ft), LRTK significantly reduces satellite positioning errors using RTK technology. Note that to achieve high accuracy you need an open outdoor environment that receives sufficient GNSS signals; accuracy may degrade in tunnels or urban canyons among high-rise buildings. In such cases, consider additional measures (base station setup or post-processing) as needed.

Q3. Is there a limit to the area that smartphone LiDAR can scan at once? A. The LiDAR sensor’s effective range is on the order of a few meters, but by moving while scanning you can continuously capture point clouds for areas on the order of tens of meters to 100 m (328.1 ft). For example, walking in a straight line records a wide area along the walking direction, and in some cases you can cover an entire playing field in a single scan. However, it is not realistic to densely capture very large areas (e.g., several hundred meters square) at once. In those cases, divide the area and scan in multiple passes, then merge the data afterward. The LRTK Phone app also includes a photogrammetry mode, so you can supplement areas beyond LiDAR’s reach with photo-based capture.

Q4. Even if it’s high-precision equipment, isn’t it still just a smartphone? Does it fall short compared to traditional surveying instruments? A. The smartphone advantage is its ease of use and mobility; by contrast, it is inferior to dedicated instruments in sensor performance and ruggedness. For example, commercial laser scanners can measure targets 100 m away with millimeter accuracy, whereas smartphone LiDAR only reaches a few meters and yields somewhat sparser point clouds. Also, dedicated instruments offer greater assurance for use in rainy or harsh environments. However, in terms of positional accuracy, LRTK brings smartphone-based solutions up to professional levels, and for typical measurement distances (roughly within 5–10 m (16.4–32.8 ft)) smartphones deliver sufficiently practical accuracy and repeatability. It’s about “using the right tool for the job”: use conventional instruments when millimeter accuracy or long distances are required, and use smartphone + LRTK when centimeter accuracy with mobility is prioritized. In many sites, a few centimeters (cm level accuracy (half-inch accuracy)) is sufficient, so we recommend starting with easy smartphone surveying.

Q5. How can captured point cloud data be used? Can CAD software or other tools handle it? A. Captured point cloud data can be viewed directly in the *LRTK Cloud 3D viewer* for distance and area measurements. You can create cross-sections, overlay with other point clouds for comparison, all in the cloud. Point cloud data can also be exported in standard file formats, making it easy to import into CAD or point cloud processing software. For example, you can download LAS files or coordinate-attached XYZ data and load them into your in-house CIM tools to compare with design data. Additionally, using high-precision coordinate lists and photos captured alongside point clouds will greatly streamline report creation and as-built drawing generation.

Q6. Can people who aren’t good with devices use it? I’m worried about on-site operation. A. Rest assured. LRTK-enabled apps are designed to be *user-friendly*, with intuitive operations for positioning and scanning. App controls are simple—key operations like “Start Positioning” and “Start Point Cloud Scan” can be executed with a single tap. Results are visually confirmed in a 3D view, so there is no need to interpret difficult numbers. In practice, site workers unfamiliar with ICT have begun using the system after short training sessions and quickly performed point cloud measurements independently. If users get stuck, on-screen guides and our support services will assist you, so even first-time users can operate with confidence. Once accustomed, some even say it is easier than traditional transit or leveling instruments.

The above answers the main questions about point cloud measurement with LRTK and smartphone LiDAR. Please take advantage of high-precision yet easy 3D scanning to improve your operational efficiency and promote DX.

Dramatically Improve On-Site Surveying Accuracy and Work Efficiency with LRTK

The LRTK series delivers centimeter-level high-precision GNSS positioning for construction, civil engineering, and surveying, enabling significant reductions in on-site time and major productivity improvements. It supports the Ministry of Land, Infrastructure, Transport and Tourism’s *i-Construction* initiative and is an optimal solution to support digitalization in the construction industry. For details on the LRTK series, please visit the [official site](https://www.lrtk.lefixea.com/).