iPhone 3D scanning speeds up disaster investigations! The impressive domestic LRTK technology with cm level accuracy (half-inch accuracy)

When a natural disaster occurs, quickly and accurately understanding the situation on site is critically important. By using the latest technology called iPhone 3D scanning, anyone can use a smartphone to record disaster sites in three dimensions, aiding rapid disaster investigations. The key that supports that accuracy is the domestically developed positioning technology LRTK, which boasts cm level accuracy (half-inch accuracy). This article explains in detail how the combination of iPhone 3D scanning and LRTK technology is transforming disaster investigation and delivering great effectiveness for local governments and surveying teams.

Table of Contents

• Rapid investigations required at disaster sites

• Conventional disaster investigation methods and their challenges

• How iPhone 3D scanning revolutionizes fieldwork

• Limitations of smartphone-only positioning accuracy

• The domestic technology “LRTK” that achieves cm level accuracy (half-inch accuracy)

• How disaster investigation changes with iPhone 3D scanning × LRTK

• Benefits for local governments and disaster management officials

• Benefits for surveying and construction technicians

• Points and precautions for field deployment

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

Rapid investigations required at disaster sites

Disaster response is truly a race against time. In recent years, disasters have become more frequent and larger due to factors such as climate change, raising the importance of speed and accuracy in initial surveys. When large-scale disasters such as earthquakes or heavy rains occur, it is required to quickly survey and understand the damage and share that information among stakeholders. For example, if the size of collapsed buildings or landslides can be measured quickly, planning for rescue operations and arranging recovery work will proceed smoothly. If initial response is delayed, the risk of expanded damage or secondary disasters increases and the timing for rescue and recovery can be missed. Therefore, a new method that allows personnel to go to the site, immediately record detailed conditions, and obtain accurate data is strongly desired. Against this background, the need for disaster prevention DX (digitalization) utilizing drones and 3D technologies is growing.

Conventional disaster investigation methods and challenges

Traditionally, disaster site surveys centered on visual inspections by personnel and measuring with tape measures or surveying instruments. Sometimes specialized surveying teams bring total stations or GNSS surveying equipment to the site, but preparing and setting up the equipment takes time, and work under aftershock conditions or bad weather is dangerous. Aerial photogrammetry (drone, etc.) is also used to grasp wide-area damage, but piloting and data processing require specialized skills, and obtaining immediate on-site results is not easy. If communication infrastructure is damaged, even sending and receiving data can be difficult. In short, conventional methods had limits in rapidly obtaining accurate on-site data and sharing it with stakeholders.

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

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

• Required equipment: Conventional methods require surveying instruments, tripods, and multiple people; new technology requires only a smartphone and a small receiver, and one person can complete the task

• Position accuracy: Conventional methods without surveying GPS have errors of several meters (several ft); new technology with RTK achieves ± several centimeters (± several inches)

• Safety: Conventional methods make approach measurements at dangerous spots difficult; new technology allows non-contact measurements from a distance

• Data sharing: Conventional methods distribute paper drawings and reports later; new technology enables real-time sharing on the cloud

How iPhone 3D scanning revolutionizes fieldwork

In recent years, LiDAR scanners and advanced camera technologies built into smartphones such as the iPhone have made it easy for anyone to 3D scan their surroundings. By using a dedicated app and waving the iPhone while walking, you can acquire the shapes of buildings and terrain as point cloud data (a collection of many 3D points). No special surveying equipment or complex operation is required, and a single smartphone can record the scene three-dimensionally “as is.”

This iPhone 3D scanning technology is extremely powerful at disaster sites. For example, you can scan the shape of a collapsed building from the outside with a smartphone, without having people enter the interior. Because wide areas can be recorded in a short time (on the order of minutes), you can efficiently grasp conditions within limited time. On the obtained 3D model, measurements of damaged areas and volume calculations of landslide deposits can be performed digitally afterward. Also, 3D data can be immediately uploaded from the smartphone to the cloud for sharing, allowing headquarters to confirm the damaged situation in three dimensions remotely. The fact that one person with just an iPhone can complete the process makes this a revolution in fieldwork.

Main advantages of iPhone 3D scanning:

• No special equipment required (measurements possible with just a smartphone and an app)

• One person can record wide areas in a short time

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

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

Limitations of smartphone-only positioning accuracy

However, one problem remains if you only perform a 3D scan with a smartphone: position accuracy. Typical smartphone built-in GPS can have errors on the order of a 5–10 m (16.4–32.8 ft) radius, which is not uncommon. Even if the shape of the 3D model obtained by scanning closely reproduces the actual size on site, the model’s absolute position (latitude/longitude and elevation) can be offset by several meters. Meter-level errors are insufficient for accurately reflecting damage on a map for disaster response or revisiting the same point later to compare changes. In particular, obtaining accurate height (elevation) information is limited with smartphone-only positioning. In other words, to utilize iPhone 3D scans as formal survey data, you need measures to dramatically improve position accuracy.

The domestic technology “LRTK” that achieves cm level accuracy (half-inch accuracy)

The solution to this problem is the high-precision positioning solution LRTK developed domestically. LRTK (pronounced “el-ar-tee-kay”) is a pocket-sized RTK-GNSS receiver that can be attached to a smartphone and turns the phone into an all-purpose surveying tool with cm level accuracy (half-inch accuracy). RTK stands for Real Time Kinematic, a technology that achieves centimeter-level high accuracy in GNSS (GPS, etc.) positioning by adding correction data. By attaching LRTK to an iPhone using a dedicated case and using an app for positioning, the position errors that were typically about 5–10 m (16.4–32.8 ft) can be improved at once to accuracy on the order of ± several centimeters (± several inches).

The LRTK device was developed by a domestic startup company (a venture from Tokyo Institute of Technology). Despite being very compact and lightweight—weighing approximately 125 g and with a thickness of 13 mm (0.51 in)—it houses 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 such as GPS, GLONASS, Galileo, and QZSS (Michibiki), enabling stable positioning even in environments with heavy shielding. Start positioning by simply launching the app and pressing a button—no difficult settings or special skills are required. Field measurements have confirmed cases where horizontal position accuracy averages below 1 cm (less than 0.4 in), achieving accuracy comparable to expensive Class 1 GNSS surveying instruments. The fact that centimeter-level positioning, which previously required specialized equipment, can now be achieved with just a smartphone and a small receiver is groundbreaking.

As an additional advantage unique to domestic technology, LRTK is optimized for Japan’s geodetic systems and services. It supports the centimeter-level positioning augmentation service (CLAS) provided by the quasi-zenith satellite Michibiki, so it can maintain high accuracy from satellite correction signals even in disaster-affected areas with no mobile coverage (it also supports network-based RTK via the internet). The positioned coordinates are automatically converted and displayed in Japan’s plane rectangular coordinate system and elevation (geoid height), so data can be used directly with municipal or national official coordinate systems. On-site data can be saved and shared to the LRTK cloud with one button, allowing staff in the office to immediately check conditions on a map. In this way, LRTK provides centimeter-level positioning in an easy-to-use form as a domestic technology, enabling a level of rapid field surveying not seen before.

How disaster investigation changes with iPhone 3D scanning × LRTK

Combining smartphone 3D scanning with LRTK positioning dramatically streamlines information collection at disaster sites. The workflow on site is also simple. Attach LRTK to the iPhone and start the app, then walk around the affected area to scan; 3D point cloud data is generated in real time. Because LRTK assigns high-precision latitude, longitude, and elevation information to each point, the resulting point cloud aligns precisely with its location on a map. After scanning, the data can be uploaded to the cloud on the spot. Headquarters and other teams in remote locations can immediately share and view high-resolution 3D data via a web browser.

On-site usage image:

• Attach 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 assigns cm level accuracy (half-inch accuracy) coordinates to the point cloud, and it is immediately displayed on the map

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

• Remote headquarters can confirm and analyze 3D data in real time

LRTK also has a subject-positioning function that measures the coordinates of distant objects through the camera, even if you cannot directly touch them. Using this, you can record positions from a safe location for the top of a collapsing slope that is unsafe to approach or the upper parts of a building. Because data from hazardous areas can be obtained without omission, survey comprehensiveness improves significantly.

With this iPhone 3D scanning + LRTK workflow, surveying and drawing tasks that used to take 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 of soil need to be removed. Complex terrain is accurately reproduced on a 3D model, helping 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 advantage of small equipment. Even when large equipment could not be brought in, detailed 3D terrain data around collapsed houses was acquired in a short time, aiding later damage assessment and recovery planning. This case demonstrated the usefulness of this technology in initial response to large-scale disasters. A new era of disaster investigation that combines speed and accuracy has truly arrived.

Benefits for local governments and disaster management officials

By utilizing this technology in municipal and disaster management operations, initial response capability and the accuracy of information sharing can be dramatically improved. Because officials themselves can obtain detailed on-site data, they can make rapid judgments and decisions. Main benefits are summarized below:

• Rapid situation awareness: Obtain 3D damage data on site immediately, accurately grasp the scale of damage, and link this to early decision-making

• Staff safety ensured: Even for dangerous collapsed buildings or unstable ground, measurements can be taken from a safe distance, reducing the risk of secondary disasters during surveys

• Smooth information sharing: Because data can be shared immediately via the cloud, damage conditions can be shared in real time with the national government and other municipalities, smoothing support requests and coordination (viewable in a web browser without special software at the receiving end)

• Accurate records and reporting: Based on cm level accuracy (half-inch accuracy) data, you can present precise figures when creating damage reports and recovery plans, aiding the calculation of reconstruction budgets and insurance claims

• Continuous monitoring: By re-scanning the same points during recovery, you can quantitatively compare changes over time, useful for evaluating recovery progress and monitoring signs of secondary disasters

Benefits for surveying and construction technicians

For technicians working in surveying and construction, the combination of iPhone 3D scanning and LRTK brings major innovation to workflows. Not only does it dramatically improve efficiency and reduce labor compared to conventional surveying, it also greatly increases the volume and freshness of obtainable data. From an expert perspective, main advantages are summarized below:

• Dramatic improvement in work efficiency: No need to carry and set up heavy tripods and equipment; surveying can be completed with a smartphone in hand. One person per device can survey concurrently, allowing efficient response even when staff are limited

• Immediate use of high-precision data: Obtain high-precision point cloud data and coordinate lists immediately after scanning; easy to import into CAD drawings and GIS maps. Because the data conforms to as-built management guidelines, it can be used as official deliverables (accuracy can be verified and adjusted with known points if necessary), reducing reporting workload

• Enhanced quality control and inspection: By 3D scanning on site during construction and comparing with the design model, you can instantly check the as-built status of embankments and structures. Using AR to project design lines on site during construction prevents rework and errors

• Risk reduction through increased frequency: Lower cost and effort for surveying enables more frequent fixed-point and time-lapse observations than before. Early detection of ground subsidence or structural displacement allows countermeasures before trouble occurs

• Accurate guidance to surveying points: LRTK’s coordinate navigation function helps you relocate control points or previously surveyed points hidden by vegetation or soil. Accuracy and efficiency of piling and repeated surveys improve

• Skill transfer and human resource development: Because operation centers on intuitive smartphone handling, even newcomers can learn quickly, reducing the burden on skilled technicians and facilitating smooth transfer of surveying skills. Veterans can focus on data analysis and decision-making while digital tools support field measurement tasks

Points and precautions for field deployment

Although it is a new technology, deployment is relatively easy, and with a few points in mind it can be smoothly utilized on site. First, it is important that staff become familiar with iPhone 3D scanning and LRTK operations during normal times. Actively using them in disaster drills and routine inspections will allow calm, effective use in emergencies. Also, GPS positioning requires an open view of the sky, so ensuring sight lines and choosing measurement points wisely are important for maintaining positioning accuracy (LRTK has strong satellite acquisition capability, but operations such as fixing positioning outdoors before entering tunnels can be effective). Fortunately, LRTK’s operation is simple and it begins positioning automatically when powered on, so it can be handled with minimal steps even during emergencies. Keep the smartphone and receiver charged and regularly update software; with these basic preparations, the technology will deliver maximum performance when needed. In terms of cost, LRTK is offered at a price point more accessible than conventional high-precision surveying equipment, 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, but efforts to prevent damage expansion are advancing through the use of the latest technologies. The new surveying approach that combines the simplicity of the iPhone with 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 surveying and quickly share information. This approach overturns conventional wisdom and will bring great benefits not only to disaster response but also to everyday civil engineering and surveying operations. Simple surveying using smartphones is expected to strongly promote DX (digital transformation) in construction and disaster prevention fields. As smartphone sensors and processing power improve year by year and LiDAR resolution increases, the accuracy and efficiency of simple surveying will further improve. In disaster-prone Japan, LRTK technology could become a trump card to dramatically boost on-site capabilities, and its development is one to watch.

In addition, LRTK technology is highly compatible with drone aerial surveys, and by integrating wide-area point clouds obtained from the air with detailed point clouds obtained on the ground, you can capture both the overall picture and the details of a disaster site without omission. Furthermore, by overlaying acquired 3D data and design drawings on site with AR (augmented reality), you can use them for recovery work planning and stakeholder image sharing. Consider adopting domestic technology–based simple surveying in the field to help prepare for future disasters and improve daily work efficiency.

The iPhone 3D scanning and LRTK combination is likely to become the new standard for disaster investigation in the near future. Expectations for future developments remain high! Be sure to pay attention to the transformation this new technology will bring.