Land and Building Surveyors Do RTK Positioning with Smartphones! Improving Work Efficiency with an LRTK Implementation Case

For those of you working daily on boundary determination and surveying as land and building surveyors, precise positioning is an indispensable part of the job. Until now, surveying work commonly required large equipment such as tripods-mounted transits or large GNSS receivers, carefully set up to carry out measurements. However, that conventional wisdom is changing dramatically. By combining a smartphone with a pocket-sized high-precision positioning device, an era has arrived in which boundary points can be positioned surprisingly easily. Introducing the latest smartphone-compatible RTK positioning system, LRTK, can streamline field surveying work so much that even professional land and building surveyors will be surprised. This article explains the basics of GNSS and RTK technology, how LRTK works, the challenges in conventional surveying work, and the concrete benefits and usage points of smartphone RTK introduction. Finally, we will show how simple surveying with LRTK can help in the daily work of land and building surveyors.

Basics of GNSS Positioning and RTK Technology and How LRTK Works

GNSS (Global Navigation Satellite Systems) are indispensable when measuring positions on Earth. By receiving signals from satellites such as GPS, GLONASS, Galileo, and Japan’s Michibiki (quasi-zenith satellite), you can determine your position. However, with ordinary GNSS positioning, errors of several meters (several ft) often occur due to signal delays and reflections. For boundary-point surveying handled by land and building surveyors, errors of several meters are unacceptable, and this is where the high-precision positioning technology RTK (Real-Time Kinematic) is used.

RTK positioning operates two GNSS receivers simultaneously: a base station with known coordinates (reference station) and a rover (mobile station). The base station sends error correction data to the rover, dramatically improving the rover’s positioning accuracy. As a result, positioning errors that would normally be several meters (several ft) can be reduced in real time to the order of several centimeters (several in). Because RTK can provide centimeter-level accuracy immediately, it is highly valued for construction as-built management and boundary surveying.

The recently introduced LRTK is the latest system for making this RTK positioning easy to use with a smartphone. LRTK is a pocket-sized RTK-GNSS receiver that mounts on the back of a smartphone. It contains a high-performance GNSS antenna and positioning engine and, when linked via Bluetooth to a smartphone app, enables centimeter-level positioning in real time.

LRTK achieves high precision by using multiple correction sources. In environments with internet access, it obtains correction data via the Ntrip protocol from the Geospatial Information Authority of Japan’s control point network or commercial reference station services to enhance accuracy. There are also models that can directly receive the centimeter-level augmentation signals (CLAS) provided by Japan’s Michibiki, allowing positioning in mountainous or other areas without cellular coverage. This means that even at sites without mobile communications, RTK positioning can continue using satellite-based augmentation information alone.

The LRTK receiver itself is an all-in-one design with integrated battery and antenna, weighing only about 100–200 g and with a thickness of around 1 cm (0.4 in), making it extremely compact. It can be carried like a smartphone case and taken out to start surveying as soon as needed. When connected to a smartphone via Bluetooth and a dedicated app is launched, satellite acquisition, correction application, and coordinate display are handled automatically, turning the smartphone itself into a high-precision positioning terminal.

Another excellent feature of LRTK is that some models include tilt compensation. Even when mounted on a surveying pole, built-in sensors perform corrections if the pole is slightly tilted, accurately calculating the coordinates of the tip. This keeps measurement point accuracy even when the pole must be held at an angle to avoid obstacles, making field handling significantly easier.

In this way, LRTK condenses advanced GNSS and RTK technologies so that centimeter-precision positioning—previously requiring specialized equipment and expertise—can now be achieved easily by anyone using a smartphone.

Challenges in Conventional Surveying Work: Boundary Surveying, As-Built Surveying, and Public-Private Boundary Coordination

High-precision surveying and meticulous on-site work are required for boundary determination, as-built surveying, and public-private boundary coordination, which are core duties of land and building surveyors. However, there have been several issues with traditional methods.

First, in boundary determination work, surveyors confirm and install boundary markers in attendance with neighboring landowners, using total stations (tripod-mounted optical surveying instruments) or GNSS surveying equipment to measure with great care. Although precision can be maintained because millimeter-level errors are not tolerated, the burden is significant: transporting and setting up equipment takes time, and at least two people—a surveyor and an assistant—are typically required. Even measuring a single boundary point often requires repeated equipment setup and movement, and it is not uncommon for field surveys to take a whole day.

In as-built surveying (surveying to capture the current state of the land), many points such as site shape, elevation differences, and the positions of existing structures must be measured. Traditionally, this has involved manual methods using tape measures or leveling rods, or painstakingly sighting each point with a total station. The more measurement points, the more complex the work becomes, and data were often recorded by hand and later digitized—resulting in repeated work. If points were missed in the field, revisits were necessary, leading to inefficiency.

In public-private boundary coordination (confirming boundaries between private land and public land such as roads), meetings with municipal officers are held on-site to establish the boundary line. This requires preparing survey maps and cadastral maps in advance, locating past boundary markers, and confirming their positions on site. If boundary markers are missing or it is difficult to grasp the positional relationship between map coordinates and the site, additional surveying work or prolonged discussions can result. Traditional surveying equipment makes it difficult to intuitively visualize “where the boundary line runs” on the spot, making it time-consuming to obtain a shared understanding among all stakeholders.

A common thread among these issues is the inefficiency of equipment and workflows. The burden on land and building surveyors includes transporting and setting up heavy equipment, securing multiple personnel, and shuttling between the field and the office for data organization and drawing creation. While it is natural to spend time and effort for accuracy, if this process can be streamlined, freed time can be allocated to other tasks or to handling more projects.

Benefits and Work Efficiency Gains from Introducing Smartphone RTK

Introducing a smartphone plus an RTK positioning device to the field can dramatically streamline traditional surveying work. Here are some specific benefits.

• High mobility and speed: You can start surveying immediately with a smartphone taken from your pocket; simply point the device at the point to be measured and press a button to instantly acquire coordinates. Device setup time is eliminated, giving you the mobility to measure whenever the need arises. Tasks that used to take half a day to confirm boundary points can now be completed in just a few tens of minutes for several points.

• Single-person surveying: Smartphone RTK eliminates the need for an assistant, enabling solo surveying. By mounting the smartphone setup on a dedicated pole, you can comfortably measure from a boundary stake at your feet to a point out of reach, like using a selfie stick. There is no need for another person to hold a prism or leveling rod, allowing you to work at your own pace.

• Professional-grade high accuracy: Despite their small size, these devices offer impressive positioning accuracy. RTK corrections provide errors within a few centimeters (a few in), delivering measurement results comparable to conventional large equipment. Using averaging functions, you can observe a point multiple times to improve accuracy down to the millimeter level, making it suitable for precision-requiring tasks such as boundary surveying.

• Visualizing survey results with AR: Using the AR (augmented reality) function in compatible apps, measured points and preloaded boundary line data can be overlaid on the smartphone camera view. Boundary lines and survey points appear as if drawn on the ground, allowing you to explain survey results intuitively to stakeholders. Boundary markers hidden in vegetation can be located by following AR guidance.

• Automatic on-site distance and area calculation: The app can instantly calculate distances between multiple measured points and the enclosed area. For example, you can measure the distance between distant boundary markers on-site and compare it with values on cadastral maps with a single tap. This eliminates reliance on calculators or manual computations and enables quick numeric confirmation during on-site discussions.

• Cloud integration for data management: Coordinate data obtained during positioning can be uploaded to the cloud in real time. Information acquired in the field can be checked immediately from the office PC or shared with colleagues, preventing the need to transcribe paper field books and reducing errors. Automatic saving of raw surveying data also improves the reliability of records.

• Low-cost and easy to introduce: Compared to traditional surveying equipment, smartphone RTK devices are more affordable and have a low barrier to introduction for land and building surveying offices. Equipping one device per person is realistic, enabling all staff to carry high-precision positioning tools at all times. This leads to overall productivity improvements for the organization.

By adopting smartphone RTK positioning, you can achieve time savings and labor reduction across all aspects of surveying while maintaining accuracy. It offers a powerful means of improving fieldwork processes for land and building surveyors by significantly boosting efficiency without sacrificing results.

Practical Usage Points: Inspection Records, Report Creation, and On-Site Response with AR

Smartphone RTK is powerful in various daily surveying scenarios. Utilizing it in the following ways can further improve efficiency and service quality.

• As a record tool for inspection tasks: Smartphone RTK is useful for regular inspections of boundary markers and site condition checks. Because data including date/time and point names are saved automatically during positioning, it can serve as a field log. For example, when checking whether an existing boundary stake has moved or been damaged, you can measure its current coordinates on the spot and compare them with past data to immediately determine if there is an anomaly. In post-disaster land assessments or infrastructure location checks, you can leave photos and notes with centimeter-level position information, facilitating later report preparation.

• Improving efficiency in creating survey deliverables: Field-acquired data are stored digitally in the cloud, allowing direct use for drawing creation and report organization after returning to the office. With dedicated tools, you can export coordinate lists as CSV files or import them directly into CAD software to draw survey maps. Because data can be obtained in preconfigured coordinate systems (such as plane rectangular coordinate systems or geoid heights), coordinate transformations for submission to the Geospatial Information Authority or the Legal Affairs Bureau are unnecessary. Automatically reflecting previously manually entered numbers reduces human error and greatly shortens processing time.

• Clear on-site response with AR display: At boundary meetings or public-private coordination sites, the AR function of smartphone RTK serves as an effective communication tool. By showing stakeholders the boundary line and survey points at life-size through the smartphone screen, everyone can instantly understand “where the land starts and ends.” This helps people intuitively grasp positional relationships that are difficult to convey with words or maps alone, smoothing consensus building. Following AR navigation to locate hidden boundary markers reduces wasted search time on site. When a surveyor explains while viewing the smartphone screen with the client, trust increases and communication during the job becomes smoother.

Considering these points, easy high-precision “simple surveying” with a smartphone contributes not only to efficiency but also to improving the quality of surveying services and customer satisfaction.

Conclusion: Why Simple Surveying with LRTK Helps Land and Building Surveyors in Daily Work

Simple surveying with LRTK, using a smartphone and a small GNSS receiver, is poised to bring major changes to the work style of land and building surveyors. Advances in GNSS/RTK technology and digital connectivity not only dramatically streamline surveying tasks that used to require substantial time and effort, but also improve the quality of on-site responses. Making it possible for anyone to “quickly obtain accurate positions” in routine tasks such as boundary checks and as-built surveys allows surveyors to spend more time on professional judgment and adjustments that draw on their expertise.

In practice, styles such as completing surveys solo with LRTK or explaining results to clients using AR are gradually becoming more common. Many professionals are surprised and impressed at how such detailed on-site surveying, which was once difficult, can now be done “so easily.” With rapid technological progress, the field of land and building surveying is undoubtedly undergoing a digital shift.

Finally, it is important to emphasize that LRTK enables both efficiency gains and accuracy improvements. By incorporating simple surveying with LRTK, you can speed up and reduce labor in surveying while maintaining the reliability of results. This is a significant advantage for surveyors and leads to overall improvements in work processes. Equipping yourself with the new tool of smartphone RTK for daily surveying tasks will help the future of land and building surveying evolve to be faster and smarter.