Boundary Surveying Made So Easy with High-Precision Positioning! LRTK Use Cases for Land and Building Surveyors

Introduction Installing boundary markers and surveying land are routine tasks for land and building surveyors, but their accuracy and efficiency have always been major challenges. Traditional surveying required ensuring line-of-sight in narrow residential areas, operating equipment with multiple people, and performing cumbersome office work after fieldwork, all of which involved considerable effort. However, in recent years, satellite positioning technologies represented by GPS have advanced dramatically, and by leveraging a high-precision GNSS positioning system called LRTK, boundary surveying can now be performed astonishingly easily and accurately. This article explains how LRTK achieves centimeter-level accuracy (cm-level (half-inch accuracy)) and how easy it is to introduce, and shows how it can solve the conventional problems of boundary surveying. We also present real-world cases of land and building surveyors using LRTK in the field—such as in urban residential areas, mountainous farmland, and re-surveying existing boundaries—and examine the concrete benefits (single-person fieldwork, streamlined report output, AR-assisted joint inspections, etc.). Finally, we summarize how this easy high-precision surveying provided by LRTK is useful for land and building surveyors.

What is LRTK, the centimeter-accuracy GNSS positioning?

LRTK is a system that achieves centimeter-level positioning (cm-level (half-inch accuracy)) by combining a portable high-precision GNSS receiver with a smartphone app. GPS on a typical smartphone can have errors of several meters (several ft), but LRTK uses real-time kinematic (RTK) techniques and applies correction information to the satellite positioning signals to greatly reduce errors. Specifically, it uses services such as Japan’s quasi-zenith satellite “Michibiki” centimeter-level augmentation service (CLAS) to correct positioning accuracy and obtain precise position information from the global navigation satellite system (GNSS) anywhere. Furthermore, LRTK receivers pick up signals not only from GPS but also from multiple satellite systems such as Japan’s Michibiki, Russia’s GLONASS, and Europe’s Galileo. By using multiple satellites simultaneously and supporting multiple frequency bands such as L1/L2/L5, the design reduces ionospheric errors and multipath (reflected wave) effects, enabling stable high accuracy even in challenging environments. As a result, position determination with an accuracy of several centimeters (several cm (several in)), which was once difficult, becomes possible with a portable small device.

Easy to introduce and convenient

A major feature of the LRTK system is how easy it is to introduce. Simply attach a dedicated compact GNSS receiver to a smartphone or tablet and launch the app to begin high-precision positioning. The device is lightweight and compact enough to fit in a pocket, so there is no need to carry heavy tripods or fixed surveying instruments (a simple monopod can be used when needed for stable measurement). Initial setup and operation are intuitive: just tap a button on the smartphone screen at the point you want to measure to record latitude, longitude, and elevation. Another attractive point is that LRTK systems cost less to introduce compared to conventional high-precision GNSS equipment. There is no need to buy a new large dedicated device or install a base station, so it can be introduced relatively easily. It is designed to be usable without specialized training, and the fact that anyone can easily start centimeter-level positioning (cm-level (half-inch accuracy)) makes it appealing to both veteran and younger land and building surveyors.

Moreover, LRTK can be used in mountainous or radio-dead areas where mobile internet is unavailable. Because correction information can be received directly from artificial satellites, high-precision positioning does not stop even at sites without mobile coverage. Locations that traditionally required installing a base station or long static observations can obtain accurate positions simply by turning on the device on-site with LRTK. For example, mountain surveys once required static surveying—setting up dedicated reference points and recording data for extended periods—but with LRTK, equivalent-precision coordinates can be obtained in tens of seconds to a few minutes. This ease of use and broad coverage enable stable high-precision positioning at sites across Japan.

Challenges in conventional boundary surveying

What exactly does LRTK make so “easy”? To understand that, let’s first look back at the main challenges land and building surveyors faced with traditional boundary surveying.

• Securing line-of-sight is difficult: With conventional total stations and optical surveying, a straight line of sight between the instrument and the target (prism or staff) is required. In residential areas, houses and fences block the view, and trees get in the way in forests. To avoid obstacles, surveyors would increase measurement points or, in some cases, require tree clearing or permission to enter neighboring land. Securing line-of-sight was a recurring headache in boundary surveying.

• Work assumes multiple people: Optical surveying is usually carried out by two or more people. One person operates the instrument while another places the prism at remote boundary points. Because human resources are needed, scheduling is difficult, and labor and travel costs are significant. In narrow sites or along busy roads, ensuring the assistant’s safety is also a concern. The conventional wisdom was that boundary surveying was difficult to perform alone.

• Administrative burden: Surveyors must also perform coordinate calculations, drawing creation, and preparation of reports and registration documents based on field data. Traditionally, numbers recorded by hand in field notebooks had to be brought back and entered into CAD or calculation software in the office. Converting to the world geodetic system or calculating plane rectangular coordinates, area computations, and other complex calculations and document preparation took time and effort and were prone to errors. Especially in boundary determination surveys, where accurate coordinate values must be presented, these administrative tasks required careful attention and were burdensome.

As described above, boundary surveying demanded advanced expertise while requiring significant labor, multiple personnel, and office work. With the advent of LRTK, these issues are poised to change dramatically.

LRTK use cases by land and building surveyors

How does the field actually change when LRTK is introduced? Here are three concrete cases of land and building surveyors using LRTK: in urban residential areas, mountainous farmland, and re-surveying existing boundaries. Let’s look at the changes this new technology brings in each scene.

Smooth boundary surveying in urban residential areas

In densely packed urban residential areas, neighboring houses and fences are close by, making it difficult to secure line-of-sight from a surveying instrument to each boundary point. For instance, measuring a boundary marker located in a narrow gap between houses is problematic for optical surveying. However, with LRTK the surveyor can perform positioning directly while standing on the boundary point, so obstacles are no longer an issue. In one surveyor’s case, multiple parcel boundary points in a residential area were surveyed simply by walking to each point with a smartphone and an LRTK receiver. There was no need to set up tripods or adjust instrument angles, and mobility in tight spaces was easy. The acquired coordinates are converted on-site to Japan’s geodetic coordinate system and saved to the cloud, making later drawing creation smooth. During explanations to adjacent landowners, the surveyor could show the position of measured points on the smartphone screen to confirm the boundary location, increasing persuasiveness. LRTK has made boundary surveying in urban residential areas short and smart.

Efficient one-person surveying in mountainous farmland

In mountainous farmland or forests, boundary points are often far apart and communication environments poor. Traditionally, such sites required several people and a full day of work, sometimes with the installation of temporary reference points for surveying. However, one land and building surveyor who introduced LRTK completed boundary surveying alone in a terraced rice field area in the mountains. Because the LRTK receiver can obtain correction information directly from satellites, high-precision positioning is possible even in mountain areas without mobile coverage. The surveyor entered the site early in the morning with light equipment and used LRTK to measure each boundary stone in sequence. As long as the sky is open, there was no need to clear forest for line-of-sight; points across a ravine could be measured by moving to the opposite bank and measuring on the spot, eliminating the need to extend sight lines. As a result, surveying in mountain areas that previously required two to three people was completed by one person in about half a day. Measurement data are automatically produced as coordinates with elevation, so height relationships among points in terraced farmland with elevation differences can be accurately understood. Thanks to LRTK, efficient high-precision surveying is achievable even in harsh sites.

Powerful for re-surveys and boundary restoration

LRTK is also a powerful tool for re-surveying existing boundary markers and restoring boundaries after disasters. For example, consider a case where a boundary marker placed in a past survey has been lost and needs to be reinstalled. Traditionally, one would remeasure on-site based on old survey records and spend time restoring the position. However, if world geodetic system coordinates were recorded in the past survey, LRTK can navigate to those coordinates and place the marker. One surveyor received a request to restore boundaries for land on which he had been involved in subdividing 10 years earlier; he recalled the parcel point coordinates saved on the LRTK device, used the device’s guidance function on-site to identify the point, and placed the marker precisely. The smartphone screen provided real-time direction and distance to the target position, enabling the marker to be installed without any noticeable deviation. In earthquake or landslide damage investigations, comparing pre-disaster coordinate data during surveying helps quickly restore boundary lines. Re-surveying with LRTK fully utilizes past data while minimizing human error, making it highly useful for reliably reproducing boundaries.

Concrete benefits of introducing LRTK

As shown in the cases above, introducing LRTK brings many benefits to the work of land and building surveyors. Finally, let’s summarize the concrete effects enabled by LRTK.

• Improved positioning accuracy and reliability: LRTK reduces positioning errors to within a few centimeters (within a few cm (within a few in)), allowing boundary point coordinates to be presented with higher reliability. With positioning data managed digitally in a unified way, misreadings or transcription errors from handwritten records are reduced, greatly improving both the accuracy and reliability of survey results.

• Single-person fieldwork becomes possible: High-precision GNSS surveying can be performed by one person, dramatically improving fieldwork efficiency. Even amid labor shortages, same-day responses are possible without scheduling concerns. Eliminating the need for an assistant reduces personnel costs and offers safety management benefits (for example, surveying along narrow roads requires attention from only one person).

• Streamlined report and drawing creation: Survey data obtained with LRTK are saved to the cloud in real time and can be output in the specified coordinate system and survey result formats. For example, coordinates in the plane rectangular coordinate system, distances between parcel boundary points, and area calculations can be calculated automatically. Because positioning results can be obtained directly as world geodetic system values, there is no error or effort from coordinate conversion. This greatly reduces the time spent on coordinate calculations and CAD data entry after returning to the office. Creating cadastral survey diagrams and reports based on survey results becomes faster, shortening the preparation time for registration application documents.

• AR display supports boundary joint inspections: Combining LRTK with a smartphone’s AR (augmented reality) capabilities allows the display of boundary lines and measurement points on-site. During joint inspections, projecting a virtual boundary line or marks onto the ground via the screen helps landowners and neighbors intuitively understand the boundary location. Visualizing the line on site makes agreement easier than verbal explanations alone, facilitating smoother consensus building. In AR-guided stake installation, the device guides the user based on pre-set coordinates, making stake and sign installation accurate and simple. This technology that makes invisible boundaries visible greatly contributes to the reliability and smoothness of boundary confirmation work.

These effects mean that adopting LRTK is not just about making surveying more efficient, but also about improving the overall quality of work. Improved surveying accuracy directly reduces boundary disputes and increases client confidence, while streamlined office work creates capacity to handle more cases. The use of cutting-edge technology enables land and building surveyors to further demonstrate their value.

Conclusion: A new era of boundary surveying opened by LRTK

Incorporating high-precision GNSS into boundary surveying is transforming the work of land and building surveyors. LRTK makes centimeter-level accuracy astonishingly easy to achieve and resolves long-standing issues such as securing line-of-sight and manpower shortages. As real-world cases show, the workflow that allows one person to handle complex sites and directly reflect data into reports and drawings is revolutionary for both productivity and accuracy. New communication methods such as visualizing boundary lines with AR have emerged, evolving the boundary confirmation process itself.

Going forward, smart positioning technologies like LRTK will become powerful partners for land and building surveyors. Being able to handle difficult surveys “easily” and deliver reliable results quickly to clients is a significant added value. With boundary surveying made easier, surveyors can devote more time to core tasks such as registration and consulting. In the new era of high-precision positioning, the use of LRTK will be a key factor in dramatically improving the efficiency and service quality of land and building surveyors. It is expected that this easy surveying with high-precision technology will be used increasingly across sites and will rewrite conventional wisdom about boundary surveying. LRTK, which achieves “easy, accurate, and quick” boundary surveying, is set to become an indispensable partner in the field for land and building surveyors, and thanks to these innovative technologies, boundary surveying practices will continue to evolve steadily.