Land and Building Surveyors Will Be Amazed! LRTK Techniques to Quickly Turn Your Smartphone into a Surveying Instrument

Traditionally, surveying land and buildings required work using expensive, large-scale equipment operated by specialized land and house surveyors. However, recently that conventional wisdom has begun to change dramatically. By combining a smartphone with a compact positioning device called "LRTK", a smartphone can instantly be transformed into a high-precision surveying instrument, and surveying tasks that used to require considerable time and effort have become astonishingly easy to perform. An era is arriving in which you can carry a surveying instrument in your pocket and quickly take measurements whenever needed. It is revolutionary that smartphone positioning has overturned the old image of low accuracy and now delivers precision approaching that of professional large-scale equipment.

It may be hard to believe even for land and house surveyors and other surveying professionals, but this smartphone surveying technology is attracting attention for the convenience and efficiency gains it can bring to the field. In this article, we explain the mechanism and characteristics (positioning accuracy, operability, portability) of high-precision surveying that combines smartphones and LRTK, and introduce specific applications in the work of land and house surveyors (boundary surveys, existing-condition surveys, boundary meetings, public-private consultations, etc.). We also take a close look at the practical benefits of implementation (reduction of working time, reduction of personnel, stabilization of accuracy) as well as added value such as automation of data recording, report generation, and AR functions. Please learn about the benefits that smartphone × LRTK can bring to the fieldwork of land and house surveyors. You are sure to find tips that will be useful in your own work.

Overview and Features of Smartphone × LRTK Configuration

LRTK is a compact, high-precision positioning device that attaches to and is used with a smartphone. This small unit houses a high-sensitivity antenna that captures signals from multiple GNSS satellites and a dedicated chip that corrects positioning data in real time, and it is designed to work in conjunction with a dedicated smartphone app and cloud services. This smartphone + LRTK combination delivers pocket-sized performance comparable to conventional surveying instruments. The main features include the following:

• Centimeter-class positioning accuracy (cm level accuracy (half-inch accuracy)): LRTK supports the RTK (Real-Time Kinematic) method, and by correcting satellite positioning errors it can determine positions with an accuracy within a few centimeters (within a few inches). Whereas conventional smartphone GPS errors are on the order of several meters (several ft), by utilizing correction information from reference stations and Japan’s QZSS “Centimeter-Level Augmentation Service (CLAS)”, high-precision positioning is possible even without an internet connection. Despite being a compact device, it achieves positioning accuracy comparable to professional GNSS equipment. Furthermore, its high-performance design supporting multi-frequency GNSS enables stable positioning even in urban canyons and mountainous areas.

• Intuitive and easy-to-use operation: Surveying can be performed with a single tap using a dedicated app on your smartphone, and it does not require special expertise or complicated operations. Simply hold your smartphone over the point you want to measure and press a button, and coordinate values such as latitude, longitude, and elevation are immediately captured and displayed. Measurement data are automatically recorded, eliminating the need for handwritten notes or later calculations. Its ease of use is a major appeal—anyone familiar with smartphones can start using it right away. The app interface provides clear guidance in Japanese, so even new users should be able to operate it without confusion.

• Excellent portability and field adaptability: LRTK devices are extremely compact and lightweight and won't add bulk when attached to a smartphone. They weigh only about 150 grams, and with a thickness of about 1 cm (0.4 in), they can be carried like a smartphone case. A built-in battery means that once attached, no cables are needed and surveying can begin immediately on site. Unlike conventional stationary equipment, they do not require elaborate setup; you can quickly take them out and take measurements when needed, dramatically improving field mobility. Even in confined spaces or on sloped terrain where it is difficult to bring in heavy equipment with a large crew, being able to move freely and survey with just a single smartphone is a significant practical advantage.

Situations in which land and house surveyors' services are used

Now, let's see specifically how this high-precision surveying using smartphone × LRTK can help the work of land and house surveyors. The main application scenarios include the following:

• Boundary surveying: In boundary surveying, which determines and verifies the boundaries between parcels of land, smartphone surveying proves highly effective. For example, you can accurately measure the coordinates of boundary markers on a site on the spot and instantly compare them with the coordinate values in existing cadastral maps and land registries. Because the distance between two distant boundary markers can also be automatically calculated in the app, it is easy to check on the spot for any discrepancies between the measured results and the dimensions on the drawings. Tasks that used to be measured on site and then calculated and cross-checked at the office can now be performed in real time, dramatically improving the accuracy and speed of boundary confirmation. When installing new boundary markers, the navigation function guides you to the pre-set installation positions, allowing for efficient and accurate placement. In fact, there have been cases where boundary point verification work that used to be done in multiple visits can be completed in a single site visit.

• Existing-condition surveying: In existing-condition surveying (measuring the current state of land, including terrain and structures), use cases for smartphone × LRTK are expanding. Not only can coordinates be recorded point by point, but by combining a smartphone’s camera and LiDAR functions you can acquire many points in a short time and generate high-precision point cloud data. Because areas and elevation differences can be calculated on site from multiple measured points, understanding the land’s shape and calculating areas can be carried out smoothly. For example, walking the perimeter of an entire site alone to measure it and then creating a topographic map from that data can be done faster and more accurately than before. If the acquired 3D point cloud data with absolute coordinates is shared via the cloud, distant offices can grasp the current conditions or use it for earthwork volume calculations, contributing to the digital transformation (DX) of surveying operations.

• Assistance with Boundary Inspections: Smartphone surveying can be of great help even during boundary inspections (on-site confirmations with interested parties) conducted by land and house surveyors. Traditionally, surveyors could only set up surveying instruments and explain the measurement results verbally, but with a smartphone and AR functions they can visually indicate boundary lines and boundary points on the spot. By projecting virtual lines onto the ground through the camera and intuitively sharing "the boundary runs from here to here," participants can more easily reach a common understanding. In addition, boundary markers hidden by undergrowth or snow can be located using AR guidance displays, reducing wasted search time during inspections. Because surveying and explanations can be done with just a single smartphone in hand, the surveyor can proceed smoothly with the inspection while remaining aware of their surroundings. Furthermore, if the boundary data and photos obtained on site are saved as records, they can be shared among stakeholders as evidence (supporting documentation) of the inspection, which provides added reassurance.

• Support for public–private consultations: Even when confirming and consulting on boundaries between privately owned and publicly owned land, smartphone × LRTK demonstrates its power. Because it enables instantaneous cross-checking of your own survey results against control point coordinates and surveyed boundary values of public land managed by national and municipal governments, discrepancies in understanding can be resolved on the spot. LRTK also supports Japan’s geodetic coordinate system (World Geodetic System), so a major advantage is that public and private parties can discuss based on a common coordinate system. Even in locations outside mobile coverage, such as mountain forest boundaries, LRTK can receive augmentation signals from the Michibiki satellites and maintain centimeter-level accuracy (half-inch accuracy), allowing accurate boundary confirmation on site together with municipal officials in attendance. If consultations proceed based on such rapid and objective survey data, forming agreement between public and private parties will be smoother. Public–private consultations that traditionally required multiple follow-up meetings after taking survey results back can have fewer meetings and an overall acceleration if high-accuracy data can be shared on the spot.

Surveyors who have actually implemented LRTK have expressed surprise at how much their work efficiency has improved. One veteran surveyor said, "When I used LRTK to verify boundary stakes on site, a task that used to take half a day was finished in about an hour. It's reassuring to be able to check against the cadastral map on site." He also said that he shared the survey point data obtained during the boundary confirmation to the cloud on the spot, and by the time he returned to the office his colleagues were already able to start preparing the survey drawings. He feels the efficiency firsthand, saying, "With the introduction of LRTK, even the office work that used to be left until the next day or later can now be completed on site, which is really helpful." Surveys that used to require several people can now be done by one person, and because results can be checked immediately, site operations have become significantly smoother.

Effects of Implementation on Operational Efficiency and Accuracy Improvement

By introducing smartphone surveying, the practice of land and house surveyors can expect the following effects.

• Reduction of work time: The introduction of smartphone surveying significantly shortens the time required for various tasks. Time spent transporting and setting up heavy equipment and preparing measurements is almost eliminated, and you can start measuring as soon as you power on the device. For example, tasks like checking multiple boundary points that used to take half a day can, in some cases, be completed in a matter of tens of minutes. Measured data can be digitized and shared on site immediately, reducing the time spent organizing and calculating back at the office, so total working hours are reliably reduced. Because the freed-up time can be allocated to other tasks, this leads to a dramatic increase in productivity.

• Reducing Required Personnel (Realizing One-Person Surveying): With a smartphone × LRTK, the number of tasks that can be completed by one person increases, allowing you to reduce the manpower allocated to the field. Surveys that were traditionally carried out by two-person teams (for example, one person operating the surveying instrument while the other holds the prism to take measurements) can, with smartphone surveying, be done by simply moving to the measurement point yourself and pressing the measurement button. Eliminating the need for auxiliary staff leads to reduced labor costs and less effort in arranging personnel. Even small offices can operate efficiently, and during busy periods they can respond flexibly with "one-person surveying." Furthermore, because of the simple operation, even newcomers can handle it, making it easier for the whole team to share surveying tasks that previously relied entirely on experienced personnel, which also helps with workforce development and reducing dependence on specific individuals.

• Stabilization of surveying accuracy: By digitizing tasks that previously relied on human hands, surveying accuracy is also stabilized. Variations due to skill level and the risk of misreading are reduced, enabling consistently stable high-precision positioning. Because LRTK performs RTK-based corrections and automatically carries out coordinate calculations, calculation and recording errors are eliminated. Measured values on site can be checked and verified in real time, so any abnormal values can be detected immediately and re-measured. In this way, by establishing a system that ensures a consistent level of accuracy regardless of who performs the measurements, the quality of surveying results is raised.

In this way, the introduction of LRTK yields significant improvements in time, personnel, and accuracy, and is expected to dramatically improve operational efficiency and survey quality.

Added Value Created by Data Automation and AR Features

Using smartphones with LRTK not only improves efficiency but also brings new added value to operations.

• Automatic recording of survey data and report output: Positioning data obtained using a smartphone with LRTK are all automatically recorded along with date/time and coordinate system information. There is no need for later cleanup work like transcribing notes written in the field, and the app automatically manages point numbers and annotations, to the extent that a paper field notebook becomes unnecessary. Recorded data can be saved to and shared on the cloud with a single touch, and can be immediately viewed or downloaded on an office PC. It supports CSV export of point lists and coordinate values, and conversion to data formats for specialized software such as SIMA format, making it easy to incorporate surveying results into reports and drawings. Leaving data as electronic files directly from the field advances the digitization of operations while preventing recording errors.

• Visual on-site verification with AR features: An AR (augmented reality) feature that lets you overlay surveying data and design information onto the real world through a smartphone screen is another advantage unique to smartphone surveying. For example, if you project pre-registered boundary lines onto the live camera view on site, you can visualize the boundaries as if lines were actually drawn on the ground. You can also use AR to display the placement of buildings and the extent of site development based on measured coordinates, enabling you to share the final image. Intuitive visual information makes it much easier to explain to clients and stakeholders, reducing misunderstandings and communication errors. Because information that was previously only available on drawings can now be "seen" on site, on-site decision-making and consensus building become faster.

• High-precision photo records and improved reporting efficiency: The LRTK app allows you to attach and save precise position coordinates and orientation information determined by positioning to photos you take. When you photograph boundary markers or on-site conditions, the photos remain as data showing which point was photographed, making them persuasive evidence for later report preparation and for materials used in consultations with neighboring parties. There is no need to write locations by hand on paper photos, and the digital data can be managed and shared efficiently.

These additional features will make it possible not only to measure but also to improve operations by utilizing the acquired data, thereby increasing the value of services provided by land and building surveyors.

Summary

High-precision surveying that combines a smartphone with LRTK is bringing a revolutionary change to traditional surveying styles. Despite its compact size, it offers full-fledged surveying accuracy and functionality, making it a reliable tool that can greatly streamline the on-site work of land and house surveyors. From boundary surveys and current-condition surveys to site inspections and public-private consultations, it lowers the barriers to surveying in various scenarios and supports rapid and accurate task execution.

For land and house surveyors who have not yet adopted it, smartphone × LRTK may become an increasingly unavoidable presence. Even veteran surveyors are surprised, saying, "It's so small yet so accurate." Now that surveying conventions on site are changing, this could truly be called the dawn of digital transformation in surveying. Make good use of the latest digital tools to improve the quality and productivity of your work. Actively adopting new technologies should also help enhance your competitiveness as a professional. This LRTK approach, where a smartphone quickly transforms into a surveying instrument, should become a powerful ally for land and house surveyors. The day may not be far off when each person carries a pocket-sized surveying device to the field.