Table of Contents

• New possibilities brought by centimeter-level positioning

• Coordination between field and office enabled by cloud sharing

• Ease unique to smartphone-integrated devices

• Main functions LRTK Phone brings to the field

• Comparison with conventional surveying methods

• Conclusion: the new surveying era enabled by field DX

• FAQ

An era in which a smartphone can instantly become a high-precision surveying instrument has arrived. Until now, surveying typically required specialized equipment and experienced technicians. But today, a small device attached to a smartphone allows anyone to survey with centimeter-level accuracy. A prime example is the LRTK Phone. With the combination of centimeter-level positioning accuracy (cm level accuracy, half-inch accuracy), cloud data sharing, and smartphone integration, the LRTK Phone is truly a device that opens a new era in surveying.

On construction and civil engineering sites, aging experienced surveyors and labor shortages have become issues in recent years. Under the Ministry of Land, Infrastructure, Transport and Tourism’s push for *i-Construction*, there is demand for efficiency using ICT and for the use of 3D data. Against this backdrop, the advent of the LRTK Phone is overturning the conventional wisdom that “surveying requires large equipment and multiple people.” In this article, using the keywords centimeter-level accuracy × cloud sharing × smartphone-integrated, we explain in detail the benefits and use cases the LRTK Phone brings.

New possibilities brought by centimeter-level positioning

Conventional smartphone GPS typically has errors on the order of several meters (several ft), making it unusable for precise surveying. Enter RTK (real-time kinematic), a high-precision positioning technology. RTK combines correction information from a base station with the mobile receiver to correct positioning errors in real time, achieving errors within a few centimeters (within a few inches). The LRTK Phone is a groundbreaking device that makes this RTK method easy to use with a smartphone.

With the LRTK Phone, an ultra-compact GNSS receiver attached to the smartphone captures signals from multiple satellites and, by comparing them with reference station data obtained via a network, computes highly accurate position coordinates. Typically, correction information (so-called GPS correction services) is received via the internet, but there’s no need to worry even at sites outside of cellular coverage. It supports the centimeter-level augmentation service (CLAS) broadcast by Japan’s quasi-zenith satellite "Michibiki," allowing correction data to be obtained via satellite so centimeter-level positioning is possible even in mountainous areas or disaster sites where mobile signals do not reach. This enables high-precision positioning that used to require expensive fixed equipment or base station installation to be achieved with pocket-sized equipment.

The benefits of centimeter-level accuracy are immeasurable. For example, in layout tasks such as batter boards or stake driving, a deviation of a few centimeters (a few inches) can lead to significant errors. With the LRTK Phone, you simply place the device at the point to be measured and press a button on the smartphone to record the latitude, longitude, and elevation of that point with high accuracy. Positioning results are automatically converted to Japan’s plane rectangular coordinate system and geoid height, eliminating the tedious coordinate transformation work of the past. What used to rely on specialized surveying equipment and experienced personnel—acquiring absolute coordinates—can now be performed easily by anyone.

Coordination between field and office enabled by cloud sharing

A major feature of the LRTK Phone is the ability to instantly upload surveyed data to the cloud. Coordinates of measured points and photos taken in the field are synchronized to the dedicated LRTK Cloud with a single tap from the smartphone app. On the cloud, surveyed points are plotted on a map, and office PCs can view field data in real time via a web browser.

This cloud sharing dramatically speeds up information transfer between field and office. For example, a field worker can instantly share measured position information and point cloud data with remote designers or clients. Since data include timestamps and notes, it is possible to accurately understand what measurements were performed on site. What used to be shared via USB drives or paper drawings is now stored directly in a database from the field with the LRTK Phone.

The LRTK Cloud also includes a share-link issuance feature. To share survey data with another party, simply select the data in the cloud and generate a shareable URL. Recipients can view the data on the web without logging in (passwords or expiration settings can be applied as needed). Measurement results can also be downloaded in common formats such as CSV, DXF, and LAS, making import into CAD software or other point-cloud processing software smooth. Open data sharing via the cloud allows survey results, which used to be handled individually, to be instantly shared and utilized by all stakeholders.

Ease unique to smartphone-integrated devices

The greatest strength of the LRTK Phone is the ease of use that comes from being integrated with a smartphone. The receiver itself weighs just over a hundred grams and can be attached to a smartphone via a dedicated case or magnetic attachment. Its pocketable size allows you to carry it on site and “take it out and measure whenever needed.” There’s no need to lug around tripods like traditional surveying equipment, enabling mobile tasks such as walking around a site while measuring.

The smartphone app’s intuitive operation is also beginner-friendly. To start positioning, simply launch the dedicated app and tap a few times. Without complex settings or specialized knowledge, anyone can start high-precision surveying by following the app’s guide. With maps and camera feeds displayed on the smartphone’s large screen, the UI is vastly more intuitive compared to conventional surveying equipment. In practice, site supervisors and workers can master the LRTK Phone individually, making operations such as “one device per person” for surveying and recording realistic.

There are additional advantages to being smartphone-integrated. You can leverage the smartphone’s built-in features such as the camera, LiDAR sensor, and accelerometer. For example, the LRTK Phone can automatically embed positioning information (the capture location’s coordinates and orientation) into photos taken by the smartphone camera. This dramatically simplifies later verification of where each photo was taken and compiling reports. It can also integrate with iPhone/iPad LiDAR scanners to perform close-range 3D scanning. By combining point clouds captured by the smartphone with RTK positioning information, you can generate highly accurate 3D point clouds with coordinates right on site.

Main functions LRTK Phone brings to the field

The LRTK Phone is more than just a positioning device; it provides a variety of useful field functions. Below are some of the main functions and uses.

• Single-point positioning and recording: Hold the device over the desired point and tap a button on the smartphone to perform a one-off positioning measurement. Acquired coordinates are saved automatically and managed with point names, timestamps, and notes. Useful for measuring control points on survey plans and checking as-built conditions.

• Continuous positioning (track measurement): Records location continuously at set intervals while moving. For example, in slope or road longitudinal surveys, simply walking records track data. The track can later be reviewed as cross-sections or imported into CAD drawings.

• 3D point cloud scanning: Using the smartphone camera and LiDAR, quickly scan nearby structures or terrain to create 3D point clouds. Because the LRTK Phone continuously applies high-precision self-positioning corrections, point clouds remain less distorted even when scanning while walking, producing high-accuracy point clouds with absolute coordinates. Large terrains can be surveyed in about 1–2 minutes, and the data can be used immediately for earthwork volume calculations.

• AR-based as-built verification and design sharing: Displays measured data or 3D design models in AR on the smartphone screen. For example, by AR-overlaying a pre-created design model on site, you can check the intended finished appearance against the real scene. If buried utilities are recorded as point clouds, displaying that point cloud in AR for subsequent work allows construction that avoids buried objects to be performed by anyone. Sharing 3D models between client and contractor during meetings can also reduce misunderstandings.

• Coordinate navigation (stake-driving guidance): If target coordinates are pre-registered in the app, the smartphone will guide the user to that location like a navigator. As you approach the target, the display zooms in and arrow-based fine guidance leads you precisely to the stake-driving position. This function makes it possible to reliably find boundary markers hidden by vegetation or previously measured points.

• Position-tagged photos: As mentioned, this function records high-precision coordinates and the camera orientation at the time of photo capture. On the cloud, photo icons are mapped to their capture locations, and arrows indicate which direction each photo was taken. For infrastructure inspections tracking changes over time, you can compare photos taken from the same position and angle as in the past. This eliminates the labor of pasting photos into paper ledgers or Excel and prevents recording errors.

Thus, a single LRTK Phone can cover a wide range of tasks from surveying to recording, inspection, and as-built verification. Tasks that used to require different devices and software for each purpose can now be completed entirely in the field with just a smartphone and an LRTK Phone.

Comparison with conventional surveying methods

So, how does smartphone surveying with the LRTK Phone compare to traditional methods? Let’s compare several aspects.

• Accuracy: The LRTK Phone provides positioning accuracy of roughly horizontal ±1 cm (±0.4 in) and vertical ±2 cm (±0.8 in). Conventional instruments such as total stations and laser scanners also deliver high precision, but the LRTK Phone has the advantage that absolute coordinates can be obtained without control points. Drone photogrammetry typically requires ground control points to achieve centimeter-level accuracy, whereas the LRTK Phone can survey without placing markers on site.

• Work speed: Including equipment setup and post-processing time, the LRTK Phone is extremely fast. Positioning can begin immediately after power-up, and uploading point clouds to the cloud allows you to check and share results instantly. Drone surveys require flight planning and image processing time, and laser scanning also takes time for setup and data processing.

• Cost: The LRTK Phone is also advantageous in terms of acquisition and operating costs. By leveraging smartphones, it significantly reduces the need for dedicated equipment. There’s no need to procure expensive surveying instruments, software, or specialized operators, making it accessible to small businesses.

• Portability and constraints: Pocket-sized LRTK Phones are easy to handle and can be used flexibly in confined spaces, indoors, or under trees. Drones cannot operate in no-fly zones or indoors, and laser scanners can be difficult to transport and set up on tripods in some locations. The LRTK Phone has fewer terrain and environmental constraints, as long as a person can physically reach the measurement site.

• Operability and personnel: Surveying that once required two-person teams of skilled technicians can be performed intuitively by one person with the LRTK Phone. Because it is easy to use without specialized knowledge, the barrier to training new personnel is lowered. This is significant as a countermeasure to serious labor shortages.

While smartphone surveying with the LRTK Phone has many advantages, it is not omnipotent. For example, drones are better suited for rapidly surveying very large sites, and total stations may be preferable for structural deformation measurements that require millimeter-level precision. By choosing the appropriate method according to the task, however, the majority of routine surveying work can be made far more efficient with the LRTK Phone.

Conclusion: the new surveying era enabled by field DX

Combining centimeter-level GNSS positioning, cloud sharing, and smartphone integration, the LRTK Phone has the potential to dramatically change traditional surveying styles. If everyone carries a pocket-sized surveying device—one device per person—on-site data collection and sharing will be vastly more efficient and become the core of construction DX (digital transformation). When high-precision location information becomes routinely available, field workers themselves, rather than specialized surveying departments, will perform necessary measurements and share information in real time. This will not only increase productivity but also reduce errors and enable faster decision-making.

In the new era opened by the LRTK Phone, “surveying is no longer a special task but an extension of daily work.” With a smartphone in hand you can 3D-scan terrain on the spot, compare it with design drawings, and immediately make construction decisions. That future is already becoming reality. Spatial measurement, once reserved for specialists, is being democratized so everyone on site can handle high-precision data. Surveying will continue to evolve into a smarter, more seamless practice alongside tools like the LRTK Phone.

Make surveying on site simpler and more advanced. The LRTK Phone is a major step toward that realization. If you’ve ever thought, “I wish accurate surveying could be easier,” try LRTK’s simple surveying—you may experience a paradigm shift in surveying.

FAQ

Q: What kind of product is the LRTK Phone? A: It is an ultra-compact RTK-GNSS receiver used by attaching it to a smartphone. Paired with a smartphone, it enables centimeter-level positioning and provides various surveying and recording functions. Using a dedicated app, you can perform position measurements, point-cloud scanning, AR display, and more.

Q: Can a smartphone really achieve such high-precision positioning? A: Yes. The LRTK Phone employs RTK, a high-precision positioning technology that combines correction data from reference stations with satellite signals to reduce positioning errors. While a normal smartphone GPS has errors of several meters (several ft), using the LRTK Phone reduces errors to about 1–2 cm (0.4–0.8 in).

Q: Is specialized knowledge required for introduction or operation? A: No. Basic operations are guided within the app, so no specialized knowledge is required. It can be used by people without surveying qualifications, and first-time RTK users can intuitively perform measurements and data sharing. However, if you intend to submit surveying results as official survey deliverables, specialized expertise may be required in some cases.

Q: What tasks can it be used for? A: It can be used for layout tasks (stake-driving and marking), as-built control, land surveying, infrastructure inspection, progress measurement during construction, and more. From single-point coordinate measurement to 3D terrain scanning, photo records, and AR-based design verification, it satisfies a wide range of needs with a single device.

Q: Can it be used where GPS signals don’t reach, such as under buildings or bridges? A: The LRTK Phone can record relative positions even in GPS-denied environments by using an “indoor positioning mode” or photo-positioning features. For example, under a bridge you can obtain a reference position where GPS is available and then continue positioning beneath the bridge relative to that reference. However, in fully underground spaces real-time positioning is not possible, so ingenuity is required depending on the situation.

Q: How are survey data shared and exported? A: All measured data can be uploaded and managed in the LRTK Cloud. To share data, simply send the URL issued from the cloud and recipients can view the data in a web browser. For your own use, data can be downloaded from the cloud in CSV, DXF, or LAS formats for point clouds, and imported into your CAD or GIS software.

Q: Which smartphones are supported? A: Currently, iOS devices such as iPhone and iPad are the intended platforms (the dedicated app supports iOS). Newer iPhones with LiDAR sensors allow full utilization of the LRTK Phone’s capabilities. Watch for future Android support.

Q: What about battery life and continuous use time? A: The receiver has an internal battery and can perform continuous positioning for up to about 6 hours. It charges via a USB Type-C port and can be charged with a mobile battery, so having spare power makes long jobs manageable.

Q: Is the LRTK Phone expensive? A: Compared to traditional high-precision GNSS equipment and 3D scanners, it is priced to be accessible. Specific pricing requires inquiry, but it is realistic to equip one device per person, and adoption is progressing among small and mid-sized construction companies and surveying firms.

Q: How will surveying change going forward? A: The combination of smartphones and high-precision positioning devices will make surveying more routine and familiar. As real-time spatial information sharing and utilization environments mature, construction methods and inspection workflows will evolve significantly. Tools like the LRTK Phone will accelerate that change, and in the future it may become commonplace for everyone on site to handle surveying data. We are currently witnessing the formation of a new surveying norm.