When a natural disaster occurs, it is critically important to quickly and accurately grasp conditions on the ground. By using the latest technology of iPhone 3D scanning, anyone can record a disaster site in three dimensions with a smartphone, aiding rapid damage assessment. The key that supports that accuracy is the domestically developed positioning technology LRTK, which boasts cm-level precision. This article explains in detail how the combination of iPhone 3D scanning and LRTK technology is transforming disaster surveys and proving highly effective for local governments and surveying teams.

Table of Contents

• Rapid surveys required at disaster sites

• Conventional disaster survey methods and their challenges

• How iPhone 3D scanning revolutionizes fieldwork

• Limits of positioning accuracy with a standalone smartphone

• Domestic technology "LRTK" that achieves cm-level accuracy

• How disaster surveys change with iPhone 3D scanning × LRTK

• Benefits for municipalities and disaster management officers

• Benefits for surveyors and construction engineers

• Points and cautions for field deployment

• Summary: Strengthening disaster response capability with simple surveying using LRTK

Rapid surveys required at disaster sites

Disaster response is literally a race against time. With the increasing frequency and scale of disasters due to climate change and other factors, the speed and accuracy required for initial surveys have become even more critical. When large-scale disasters such as earthquakes or heavy rainfall occur, it is necessary to quickly survey and share the damage situation among stakeholders. For example, if the size of a collapsed building or a landslide can be measured quickly, planning for rescue operations and arranging recovery work proceeds more smoothly. Delays in initial response can increase the extent of damage and the risk of secondary disasters, and may cause missed opportunities for timely rescue and recovery. Therefore, new methods that allow immediate on-site detailed recording and accurate data acquisition are strongly desired. Against this backdrop, the need for disaster DX (digitalization) using drones and 3D technologies is increasing.

Conventional disaster survey methods and their challenges

Traditionally, disaster site surveys have relied on manual visual checks and measurements with tapes and surveying instruments. In some cases, specialized surveying teams bring total stations or GNSS surveying equipment to the site, but preparing and setting up that equipment takes time, and working under aftershock conditions or in bad weather is hazardous. Aerial photogrammetry (e.g., drones) is also used to grasp wide-area damage, but piloting and data processing require specialized skills, making it difficult to obtain immediate on-site results. Furthermore, if communications infrastructure is damaged, even sending and receiving data may become difficult. In other words, conventional methods have limits in quickly obtaining accurate on-site data and sharing it with stakeholders.

Conventional methods vs. smartphone simple surveying (new technology) comparison:

• Required time: Conventional methods take half a day to several days for field surveying and drafting; new technology can go from on-site measurement to sharing in tens of minutes

• Required equipment: Conventional methods require surveying instruments, tripods, and multiple personnel; new technology can be completed by one person with a smartphone and a small receiver

• Position accuracy: Conventional methods without surveying GPS have errors of several meters; new technology achieves ±a few cm with RTK

• Safety: Conventional methods make approaching dangerous locations difficult; new technology allows non-contact measurement while keeping distance

• Data sharing: Conventional methods distribute paper drawings or reports later; new technology shares in real time via the cloud

How iPhone 3D scanning revolutionizes fieldwork

In recent years, LiDAR scanners and advanced camera technology built into smartphones such as the iPhone have made it easy for anyone to 3D-scan their surroundings. By using a dedicated app and walking while pointing the iPhone, you can capture the shapes of buildings and terrain as point cloud data (a collection of many 3D points). No special surveying instruments or complex operations are required; with just a smartphone you can record the scene in three dimensions “as is.”

This iPhone 3D scanning technology is extremely powerful at disaster sites. For example, you can scan the interior shape of a collapsed building from the outside without entering it. Because you can record wide areas in a short time (a few minutes), you can efficiently understand the situation within limited time. On the resulting 3D model, measurements of damaged areas and calculations of soil volumes can be performed digitally afterward. Also, 3D data can be immediately uploaded from the phone to the cloud for sharing, allowing headquarters to check the disaster situation in three dimensions remotely. The convenience of completing the process alone with only an iPhone is truly a revolution in fieldwork.

Main advantages of iPhone 3D scanning:

• No special equipment required (measurement possible with only a smartphone and an app)

• One person can record wide areas in a short time

• Dangerous locations can be surveyed non-contact from a distance

• Data can be checked immediately after acquisition and easily shared over the network

Limits of positioning accuracy with a standalone smartphone

However, one problem remains if you only 3D-scan with a smartphone: the accuracy of position. Standard smartphone GPS often has errors of about 5–10 meters in position. Even if the shape of the 3D model produced by the scan can closely reproduce real-world dimensions, the model’s “absolute position” (latitude/longitude and elevation) may be off by several meters. For disaster response—accurately reflecting damage on maps or revisiting the same point later to compare changes—meter-level errors are inadequate. Height (elevation) in particular is difficult to capture accurately with a smartphone alone. In other words, to use iPhone 3D scans as serious survey data, it is necessary to dramatically improve positioning accuracy.

Domestic technology "LRTK" that achieves cm-level accuracy

The solution to this problem is LRTK, a high-precision positioning solution developed domestically. LRTK is a pocket-sized RTK-GNSS receiver that can be attached to a smartphone, turning the phone into a versatile surveying instrument with centimeter-level accuracy. RTK stands for Real Time Kinematic, a technique that achieves centimeter-level high accuracy by applying correction data to GNSS (GPS etc.) positioning. When an LRTK is attached to an iPhone with a dedicated case and used via an app, positional errors that were typically 5–10 meters shrink rapidly to ±a few centimeters.

The LRTK device was developed by a domestic startup originating from Tokyo Institute of Technology. Despite being very compact and lightweight—about 125 g and 13 mm thick—it contains a battery and antenna and can be attached with one touch using a dedicated smartphone case. This receiver supports three frequencies (L1/L2/L5) and can receive signals from multiple satellite systems including GPS, GLONASS, Galileo, and Michibiki (QZSS), allowing stable positioning even in environments with significant signal obstruction. Start positioning simply by launching the app and pressing a button—no complicated setup or special skills required. Field tests have confirmed cases where horizontal positioning accuracy averages under 1 cm, achieving accuracy comparable to expensive first-class GNSS surveying instruments. It is groundbreaking that centimeter-level positioning, which used to require specialized equipment, can now be achieved with just a smartphone and a small receiver.

As an additional advantage of domestic technology, LRTK is optimized for Japan’s geodetic system and services. It supports the Michibiki centimeter-level augmentation service (CLAS), maintaining high accuracy from satellite correction signals even in disaster-affected areas without mobile communications (though network-based RTK is also supported). Measured coordinates are automatically converted and displayed in Japan’s Plane Rectangular Coordinate System and elevation (geoid height), allowing municipalities and national agencies to use the data directly in their official coordinate systems. On-site data can be saved and shared to the LRTK cloud with a single button press, enabling staff in the office to immediately check the situation on a map. In this way, LRTK provides centimeter-accurate positioning in a simple, easy-to-use form as a domestic technology, enabling faster on-site surveys than ever before.

How disaster surveys change with iPhone 3D scanning × LRTK

Combining smartphone 3D scanning with LRTK positioning dramatically improves the efficiency of information collection at disaster sites. The on-site workflow is simple. Attach the LRTK to the iPhone and launch the app, then walk around the damaged area to scan; point cloud data will be generated in real time. Because LRTK attaches high-accuracy latitude, longitude, and elevation information to each point, the resulting point cloud aligns accurately with maps. After scanning, data can be uploaded to the cloud on the spot. remote headquarters and other teams can immediately share and view clear 3D data via a web browser.

On-site usage image:

• Attach the LRTK to the iPhone and go to the site (almost no pre-preparation required)

• Start 3D scanning with the dedicated app. Walk around the damaged area to acquire point clouds

• LRTK provides cm-accurate coordinates to the point cloud data, which is displayed immediately on a map

• After scanning, share data to the cloud with one tap

• Remote headquarters can immediately view and analyze the 3D data in real time

LRTK also includes a target positioning function that measures the coordinates of distant objects through the camera without physically touching them. Using this, you can record positions on the upper part of a slope about to collapse or the upper stories of a building from a safe location. Because data from dangerous areas can be captured without omission, the comprehensiveness of surveys is significantly improved.

With this iPhone 3D scanning + LRTK workflow, surveying and drafting work that previously required a specialist team half a day can be completed in just tens of minutes. For example, even at a large landslide site, you can immediately calculate the volume of collapsed soil on the spot and estimate how many dump trucks will be needed for removal. Complex terrain is accurately reproduced in the 3D model, helping to identify hazardous zones and predict secondary disasters. In fact, during the 2023 earthquake in the Noto region of Ishikawa Prefecture, iPhones equipped with LRTK were deployed to disaster sites that were out of communication range, demonstrating the mobility advantages of small devices. Even when large equipment could not be brought in, detailed 3D terrain data around collapsed houses was obtained quickly and used for later damage assessment and recovery planning. This case validated the usefulness of this technology in initial responses to large-scale disasters. A new era of disaster surveying that balances speed and accuracy has become a reality.

Benefits for municipalities and disaster management officers

If this technology is used in municipal and disaster prevention operations, the speed of initial response and the accuracy of information sharing will improve dramatically. Because officers themselves can acquire detailed data on-site, they can make faster judgments and decisions. Main benefits are summarized below:

• Rapid situation awareness: Acquire 3D damage data on-site immediately to accurately grasp the scale and enable early decision-making

• Ensure staff safety: Measure from a safe distance even at dangerous collapsed buildings or unstable ground, reducing the risk of secondary disasters during surveys

• Smooth information sharing: Share data immediately via the cloud so national agencies and other local governments can view damage in real time and coordinate support and cooperation smoothly (viewable in a web browser without special software)

• Accurate records and reporting: With cm-accurate data, provide precise figures when preparing damage reports and recovery plans, aiding allocation of reconstruction budgets and insurance claims

• Continuous monitoring: By rescanning the same points during recovery, quantitatively compare temporal changes to evaluate recovery progress and monitor signs of secondary disasters

Benefits for surveyors and construction engineers

For survey and construction professionals, the combination of iPhone 3D scanning and LRTK brings major innovations to work processes. It not only enables dramatic efficiency and labor savings compared to conventional surveying, but also greatly increases the quantity and freshness of acquired data. Major advantages from a professional perspective are summarized below:

• Dramatic improvement in work efficiency: No need to transport and set up heavy tripods and equipment; surveying is completed with a smartphone in hand. With one device per person, surveying can proceed in parallel, enabling effective responses even with staff shortages

• Immediate use of high-precision data: Obtain high-precision point clouds and coordinate lists immediately after scanning, facilitating easy import into CAD drawings and GIS maps. Because data conforms to as-built management guidelines, it can be used as official deliverables (accuracy can be verified and corrected using known points if necessary), reducing the effort for report creation

• Enhanced quality control and inspection: By performing on-site 3D scans during construction and comparing with design models, you can instantly check as-built conditions of embankments and structures. Using AR to project design lines on-site during construction helps prevent rework and mistakes

• Reduced risk through increased monitoring frequency: Lower surveying cost and effort allow for more frequent fixed-point and time-series observations. Early detection of ground subsidence or structural displacement enables countermeasures before major issues occur

• Accurate re-location of survey points: LRTK’s coordinate navigation function helps re-find reference points or previously surveyed points hidden by vegetation or soil. This improves accuracy and efficiency for staking and repeated surveys

• Skill transfer and workforce development: Because operation centers on intuitive smartphone use, newcomers can learn quickly, reducing burden on experienced technicians and enabling smooth transfer of surveying skills. Veterans can focus on data analysis and decision-making while digital tools support on-site measurements

Points and cautions for field deployment

Although it is a new technology, deployment is relatively easy, and paying attention to a few points will allow smooth on-site use. First, it is important that staff become familiar with operating iPhone 3D scanning and LRTK during peacetime. Actively using them in disaster drills and routine inspections will make it possible to use them calmly in emergencies. Also, GPS positioning requires an open view of the sky, so ensuring sight lines and choosing measurement points carefully is important to secure positioning accuracy (LRTK has excellent satellite acquisition capability, but in tunnels, for example, it can be effective to fix the position outdoors before entering). Fortunately, LRTK is simple to operate and begins positioning automatically when powered on, so it can be handled with minimal procedures in emergencies. Keep smartphone and receiver batteries charged and update software regularly—these basic preparations will enable the technology to perform at its best when needed. In terms of cost, LRTK is offered at a price range more accessible than conventional high-precision surveying instruments, so wider adoption across many sites is expected.

Summary: Strengthening disaster response capability with simple surveying using LRTK

Japan is a country prone to natural disasters such as earthquakes, heavy rain, and typhoons, and efforts to prevent the spread of damage are advancing through the use of cutting-edge technologies. The new surveying approach that combines the convenience of the iPhone with the centimeter accuracy provided by LRTK is a prime example. Without relying on special equipment or highly skilled technicians, anyone on-site can perform high-precision surveys and share information rapidly. This approach, which overturns conventional wisdom, will bring great benefits not only to disaster response but also to everyday civil engineering and surveying operations. Going forward, such smartphone-based simple surveying is expected to strongly drive DX (digital transformation) in the construction and disaster prevention sectors. Smartphone sensors and processing power continue to improve year by year, and with increased LiDAR resolution, the accuracy and efficiency of simple surveying will further advance. In disaster-prone Japan, LRTK technology could become a trump card that dramatically boosts field capabilities—its development deserves close attention.

Moreover, LRTK technology is highly compatible with drone aerial surveying; integrating wide-area point clouds acquired from the air with detailed ground point clouds makes it possible to fully capture both the overall picture and the details of a disaster site. Additionally, acquired 3D data and design drawings can be overlaid on site using AR (augmented reality) to support recovery planning and image-sharing among stakeholders. Consider adopting domestic-technology-based simple surveying in your fieldwork to help prepare for future disasters and improve daily operational efficiency.

The combination of iPhone 3D scanning and LRTK is likely to become the new standard in disaster surveys in the near future. Expectations for further developments are high—let’s keep an eye on the transformations this new technology brings!