Works Even Offline! With LRTK High-Precision Positioning, Land and House Surveyors Can Confidently Survey in Mountainous Areas

In the work of land and house surveyors, there are many situations where boundaries must be surveyed and confirmed in areas without network coverage, such as mountainous regions. Surveying in these field conditions has traditionally required tremendous effort and time, and ensuring accuracy has been difficult. However, in recent years a new technology called LRTK has emerged to provide high-precision positioning, enabling centimeter-level (half-inch-level) surveying even offline. This article explains in detail the conventional challenges of surveying in mountainous areas and the benefits brought by LRTK high-precision positioning.

Challenges Land and House Surveyors Face When Surveying in Mountainous Areas

Surveying in remote mountain villages, forested areas, and locations where mobile signals do not reach is a major challenge for land and house surveyors. Traditional surveying equipment and methods have posed the following difficulties:

• Difficult to secure line of sight: Optical surveying instruments such as total stations require a straight line of sight between survey points that can be visually observed, but in mountainous areas the terrain and trees often block line of sight. As a result, relay points may need to be set up to connect survey points, or survey lines may need to be cleared.

• RTK cannot be used offline: The RTK method, a high-precision GNSS surveying technique, usually achieves centimeter-level accuracy by receiving correction data from a base station via mobile communication or radio. However, in mountainous or radio-signal-free sites this correction information cannot be received, and even advanced GNSS equipment may deliver only accuracy on the order of several meters (several ft).

• Burden of personnel and equipment: To perform RTK where the internet is unavailable, one option is to set up your own base station and use radio communication, but this requires transporting and installing heavy base station equipment. Carrying thick tripods, large batteries, and survey poles into remote mountains is difficult and requires manpower for round trips.

• Increased time and decreased accuracy: Travel between points in mountainous sites takes time, limiting how much can be surveyed in a day. In environments where communication is cut off, surveyors often have to rely on manual methods such as tape measures and compasses, which reduces efficiency and tends to increase measurement error. As a result, re-surveys or additional investigations may be required later.

How LRTK High-Precision Positioning Works and Its Offline Capability

The solution to these challenges is a recently introduced high-precision positioning technology called LRTK. LRTK applies GNSS positioning using the real-time kinematic (RTK) method but enables centimeter-level (half-inch-level) positioning using satellite signals alone, without receiving correction data from a base station over the internet. The secret is the CLAS (Centimeter-Level Augmentation Service) provided by Japan’s Quasi-Zenith Satellite System, Michibiki. LRTK-compatible receivers can directly receive CLAS satellite signals and obtain correction information generated from the government’s Continuously Operating Reference Stations (CORS), allowing real-time high-precision positioning even at sites without communication infrastructure.

LRTK receivers themselves are compact and lightweight, offering excellent portability on site. For example, pocket-sized devices that attach to smartphones are available; they include an antenna and battery and weigh approximately 100–200 g. As long as the sky is visible, neither a base station nor a communication line is required, and positioning accuracy across almost all of Japan is within a few centimeters (a few in). They also support multi-GNSS (multiple satellite positioning systems) and multiple frequency bands, so they are designed to maintain stable accuracy even in mountainous environments where satellite visibility is partially obstructed. In short, LRTK is a groundbreaking technology that realizes “RTK usable even offline.”

The main features of LRTK high-precision positioning can be summarized as follows:

• High-precision GNSS with satellite augmentation: By applying augmentation from Michibiki (QZSS) CLAS signals in addition to data from GPS and other positioning satellites, errors that were on the order of several meters (several ft) with standalone positioning are reduced in real time to the centimeter level (half-inch-level).

• No communication infrastructure required (offline capable): CLAS signals are received directly from satellites, so correction information can be obtained even in deep mountains where mobile networks or Wi‑Fi do not reach. Internet connectivity or base station setup is unnecessary, enabling stable high-precision surveying in situations where communication networks are cut off by disasters or in remote islands and isolated areas.

• Compact, lightweight, and highly portable: LRTK receivers are small enough to fit in the palm of your hand and can perform positioning while held together with a smartphone without dedicated poles or tripods. They are rugged, with dust and water resistance, so carrying them through rough mountains or long hikes is not burdensome. They can also be mounted on a monopod or pole if needed, allowing flexible operation according to conditions.

• Long operation on built-in battery: Thanks to power-efficient design, LRTK devices have enough battery life to operate all day on a built-in battery. They can be used from morning to evening without charging, which is reassuring for surveys in remote mountains where power sources are difficult to secure or for work that spans multiple days.

Typical Surveying Scenarios in Mountainous Areas Where LRTK Can Be Used

The strength of LRTK is that it performs well in fields where high-precision positioning was previously difficult. It is especially useful in the following mountainous scenarios related to the work of land and house surveyors:

• Boundary surveying and boundary confirmation in forests: When confirming and measuring boundary markers in forests or valleys, traditional methods often require clearing brush to secure line of sight or rescheduling meetings with neighboring landowners. With LRTK, accurate global coordinates can be obtained on the spot at each boundary point, making boundary surveys efficient even in mountainous areas. The measured coordinate data can be immediately converted to plane rectangular coordinate systems for document preparation for boundary identification and easy inclusion in cadastral maps. During boundary confirmation with neighboring landowners, both parties can check the positioning results on site, facilitating consensus building.

• Official–private boundary inspections and consultations: LRTK is also useful in official–private boundary inspections where the boundary between national forests or public land and privately owned land must be confirmed. In boundary assessments with municipal forests deep in the mountains, traditional methods required long-distance surveying from control points, but with LRTK you can directly obtain coordinates at key locations and dramatically improve the accuracy of survey maps. During inspections with local officials, boundary positions can be discussed in real time with measured values displayed, reducing discrepancies in understanding. This enables reliable and fast official–private boundary confirmation, streamlining consultations and the preparation of agreement documents.

• Disaster recovery surveying in affected mountainous areas: After landslides or heavy rain disasters in mountain areas, roads and landforms can change drastically and boundary markers may be lost. For emergency disaster recovery field surveys, LRTK is useful because it can position independently even when communication infrastructure has been cut off. Surveyors do not need to carry full surveying equipment; an investigator carrying a smartphone-mounted LRTK receiver can record the precise locations of collapsed areas and remaining structures. Acquired data can be shared immediately with relevant agencies via the cloud, aiding the planning of recovery efforts. Even amid the confusion immediately after a disaster, LRTK enables quick and simple surveying from safe areas, significantly advancing recovery support.

Practical Benefits of Introducing LRTK

As described above, LRTK high-precision positioning brings new possibilities to surveying in mountainous areas. Finally, here are the main practical benefits land and house surveyors can expect:

• Work can be completed by a single person: Because surveying can be done with just a smartphone with a GNSS antenna, there is no need for an assistant to hold a prism. Boundary surveys that traditionally required two people can be completed efficiently by one person with LRTK, helping to address manpower shortages and reduce labor costs.

• Expanded surveyable areas: Free from constraints of communication environment and terrain conditions, you can approach survey points in remote mountains that were previously impractical. Long survey lines crossing vast forests or valleys can be recorded continuously with LRTK as if drawing a single stroke. As a result, the range of cases you can handle expands and it becomes possible to enlarge your service area.

• Reduced revisit trips: Because high-precision data are obtained in real time on site, you can notice omissions or data deficiencies and perform supplementary measurements on the spot. Everything needed can be collected in a single field survey, reducing wasted trips for “re-measurement due to insufficient accuracy” or “return visits to measure additional points.” In mountainous areas, travel time alone can be a major cost, so reducing revisits yields significant benefits.

• Improved safety: Reducing the burden of surveying work also improves safety. It lowers the risk of carrying heavy equipment along steep mountain paths and reduces the need for device installation at heights. Shorter work times also lower the risk of accidents due to bad weather or sunset. By enabling surveys to be completed “quickly, safely, and accurately,” LRTK greatly contributes to the safety of field personnel.

Conclusion: LRTK Simple Surveying Will Change Mountainous Area Surveying

LRTK technology, which enables high-precision surveying in mountainous and offline environments, is revolutionizing the field work of land and house surveyors. Boundary surveys in remote mountains that used to be difficult can now be completed easily by one person with just a smartphone and a small receiver. LRTK-based simple surveying not only dramatically improves efficiency and accuracy but also enhances work safety.

In future surveying work, being able to deliver uncompromised accuracy even in offline areas is a major advantage. By utilizing LRTK high-precision positioning to confidently survey difficult mountainous locations, you can improve both the quality and productivity of your work as a land and house surveyor. Adopting the convenience LRTK brings to the field will make possible a new surveying style that overturns conventional thinking.