DX Revolution at Land Improvement Sites: Achieving Solo RTK Surveying with a Smartphone + GNSS

The wave of DX (digital transformation) is sweeping into land improvement sites as well (such as field improvement and agricultural water facility construction). In particular, the technology that combines smartphones and GNSS (satellite positioning) to complete RTK surveying by a single person is poised to greatly change how field work is done. Traditionally, surveying required multiple personnel and long hours, but these new technologies are rapidly advancing labor and time savings on site. This article explains in detail the labor-saving effects of solo RTK surveying in land improvement projects, the operability and practicality of smartphone + GNSS, how point cloud data and AR (augmented reality) improve site visibility, and how cloud-based data sharing streamlines deliverable creation. At the end of the article, we also introduce an easy-to-use smart surveying solution called "LRTK."

Labor savings from RTK surveying that can be completed by one person

At land improvement sites, it was once common knowledge that surveying work required many personnel. With total station surveying, at least two people are needed: an operator of the instrument and a staff member holding the prism at the survey point. High-precision GNSS surveying equipment has also traditionally been bench-mounted and weighed several kilograms, requiring multiple people to carry and install the equipment in some cases. Furthermore, these instruments are expensive and require maintenance and specialized setup, making adoption difficult for small land improvement associations and local governments. Thus, even surveying alone in land improvement work involves significant personnel and cost, and with declining workers and an aging workforce, maintaining traditional methods has become difficult. In fact, the aging of technicians and the lack of younger staff in the agricultural and rural development sector is severe, and labor and personnel savings are urgently needed in land improvement associations that manage large areas with limited staff. The Ministry of Agriculture, Forestry and Fisheries is also promoting ICT use in agricultural civil engineering and smart agriculture, and the adoption of such digital technologies is being supported nationally.

The emergence of RTK surveying that can be completed by one person greatly changes these field norms. By utilizing RTK (real-time kinematic) for centimeter-level GNSS positioning, a single person can obtain high-precision coordinates alone, enabling surveying tasks that previously required two or more people to be handled solo. Dramatic reductions in personnel directly lead to labor and manpower savings, helping alleviate chronic labor shortages. Moreover, the advantage of working alone is more than just reducing headcount: it creates mobility to go to the site and measure as needed, eliminates the need to coordinate multiple schedules, and reduces waiting time. As a result, it contributes to shortening overall project schedules and reducing costs in land improvement projects.

Consider, for example, ground elevation surveys for field improvement or as-built management of irrigation channels. Tasks that used to be done by two-person teams with levels or total stations, moving measurement points repeatedly over long periods, can now be completed by one person in a short time if they have a smartphone equipped with an RTK-capable GNSS receiver. Solo RTK surveying dramatically streamlines the once-bottleneck surveying processes at land improvement sites and boosts on-site productivity.

Estimating actual working time, surveying an irrigation channel 1 km in length that formerly took two people more than half a day with conventional methods can be completed by one person in about two hours using smartphone RTK. The impact in terms of labor savings and time reduction is therefore very large.

High operability and practicality enabled by smartphone + GNSS

New surveying tools that combine smartphones and GNSS receivers are attracting attention for their high operability and practicality. Whereas traditional surveying equipment required tripods and large hardware, smartphone-mounted GNSS receivers are compact enough to fit in a pocket. By attaching a small device weighing only a few hundred grams to the back of a smartphone, you can easily take it to the field and start surveying. There is no need to assemble or adjust heavy equipment on arrival, and the ability to measure on the spot whenever needed is a major advantage.

Operation is also intuitive via smartphone apps. While dedicated controllers and traditional survey instruments had small screens and complex button operations, you can perform positioning while checking maps and values on a smartphone's large touch screen, making it easy even for first-time users. Recording measurement points, entering names, and photo documentation can all be completed with a single smartphone. There is no need to carry paper notebooks or memo pads, and measured data is automatically saved and organized, reducing human error.

What about positioning accuracy? The GPS built into a smartphone alone has errors of about 5–10 m and is unusable for surveying, but attaching an RTK-capable high-precision GNSS antenna enables centimeter-level positioning. For example, horizontal positioning accuracy of ±1–2 cm (±0.4–0.8 in) and vertical accuracy of about ±3 cm (±1.2 in) can be obtained, comparable to professional surveying instruments. Using network RTK that receives correction information over the internet from a reference electronic reference point, or the centimeter-class augmentation service (CLAS) provided by Japan’s Quasi-Zenith Satellite System (Michibiki), enables immediate high-precision positioning even with a smartphone. This gives practical capability to perform accurate surveying even in remote mountainous areas or vast farmland with limited communications.

Another advantage of using a smartphone is long battery runtime and easy power supply. The GNSS receiver itself can operate continuously for several hours or more on its internal battery and supports USB charging, so with a mobile battery it can endure a full day of surveying. Unlike heavy dedicated instruments, the convenience of carrying and frequently using it in daily work is also a major strength on site.

Main differences between traditional surveying instruments and smartphone RTK surveying:

• Mobility: Traditional instruments were heavy and required effort to transport and set up, whereas smartphone RTK is pocket-sized and quick to prepare.

• Required personnel: Traditional total stations and similar tools typically required multiple people, but smartphone RTK can be completed by one person.

• Operability: Specialized instruments required time to learn operations, but smartphone apps are intuitive for anyone.

• Cost: Compared to expensive surveying instruments, solutions that use smartphones are relatively low-cost and easier to introduce.

• Extensibility: Smartphone cameras and sensors enable high-value-added features such as point cloud capture and AR display, providing information that traditional instruments could not collect on site.

Thus, surveying systems using smartphone + GNSS achieve a practical solution that maintains high precision while offering outstanding portability and operability.

Visualizing the site using point clouds and AR

Solo RTK surveying yields more than just numerical data. Tools that combine smartphones and GNSS can also capture the site as 3D point cloud data. Recent smartphones are equipped with LiDAR scanners and high-performance cameras, and when combined with high-precision RTK positioning, they can scan topography and structures on the spot and generate detailed 3D models. While scanning with a smartphone alone can produce distorted point clouds when walking, RTK-based self-position correction suppresses data deformation during scanning and ensures accuracy. Tasks that once required drones or laser scanners, from surveying vast farmland terrain to detailed measurements of channels and slopes, can now be performed easily with a handheld smartphone. The generated point clouds are geo-referenced, so they can be readily imported into CAD drawings or GIS for design use. You can also calculate distances, areas, and volumes between any two points on the point cloud data, making it useful for earthwork volume calculations and as-built management. For example, you can immediately calculate cut-and-fill volumes from point clouds in field improvement and reflect them in construction planning. Even point clouds collected with a smartphone can achieve accuracy sufficient for deliverables compliant with the Ministry of Land, Infrastructure, Transport and Tourism’s as-built management guidelines.

AR (augmented reality) technology also allows design and survey data to be overlaid onto real-world views. Through the smartphone screen, you can confirm 3D models or design lines of the completed project while on site. For example, projecting the design lines or placement of structures for a new drainage channel onto the ground with AR lets you intuitively grasp the final appearance that would be difficult to understand from drawings alone. Positioning work that used to involve marking the ground with stakes or spray paint can be performed virtually with AR to indicate proposed stake locations, enabling safe position checks on steep slopes or paved surfaces where stakes cannot be driven. Using AR reduces the need to perform risky on-site surveying and contributes to improved worker safety. In addition, overlaying the design model with the current-site point cloud before construction makes it possible to check in advance whether construction can proceed as planned. Early detection of discrepancies between design and site allows corrections to be made, preventing rework.

This kind of site visualization offers the following expected benefits:

• All stakeholders can share the site situation and design image in 3D, reducing misalignment in understanding.

• Using point cloud data, distances, areas, and volumes can be quickly calculated, streamlining design review and as-built verification.

• Overlaying plans with the current site in AR prevents construction errors and helps ensure quality.

• Visual explanations to clients and stakeholders on site smooth consensus building and decision-making.

By actively utilizing point clouds and AR, land improvement sites become more “visible” than ever. The site conditions that could not be fully captured by drawings and numbers are digitally recreated and shared in a form that anyone can intuitively understand. Furthermore, if you link photos and notes to acquired point clouds, you can record bridge cracks or deterioration of channel walls and compare changes at the next inspection, applying the data to maintenance management. This leads to improved site management accuracy and smoother communication.

Efficient data sharing and deliverable creation using the cloud

Surveying systems using smartphone + GNSS are designed with cloud service integration in mind. Positioning data and point clouds captured in the field can be uploaded to the cloud directly from the smartphone. For example, surveyed coordinate points can be instantly plotted on a web map, allowing supervisors and colleagues in the office to check results in real time. This eliminates the need to exchange USB drives or paper records between the field and the office, speeding up information sharing and promoting paperless records. With the latest survey results available to all stakeholders regardless of location, decisions about whether additional measurements are necessary can be made immediately, and instructions can be issued on the spot (for example, a designer reviewing the site point cloud via the cloud might identify missing areas and request additional measurement the same day). This prevents later rework and return visits. In this way, a new workflow that seamlessly connects the field and the office is realized. Data are automatically backed up in the cloud, so there is no worry about losing survey results due to device failure or loss.

Using the cloud also greatly streamlines post-survey creation of deliverables. Conventionally, field-acquired coordinates had to be manually compiled into tables and input into CAD software for drawing, which was time-consuming. On the cloud, positioning data are stored in an organized manner and can be easily exported in the required formats. You can output coordinate lists in CSV or spreadsheet-compatible formats, or download point clouds in DXF or LAS formats and import them directly into design software with a single click. Creating plan and cross-section drawings or quantity calculation sheets based on survey results can be done smoothly without time-consuming data conversion. You can also display 3D site data directly in a cloud-based point cloud viewer, measure necessary dimensions, and reflect them in drawings right from the browser. These capabilities reduce desk work and manual calculations after returning to the office, allowing you to focus on more creative design and review tasks.

Moreover, accumulating survey data in the cloud builds a digital record useful for maintenance management of land improvement facilities. For example, you can retrieve and compare pre- and post-construction terrain data at any time, making it easier to verify construction effects and detect changes over time. Past data can be used when planning future repairs, contributing to long-term DX in asset management. Cloud integration is not just data storage; it transforms the way people work in land improvement, improving overall efficiency and quality.

Conclusion: Land improvement DX enabled by solo RTK surveying and the use of LRTK

As we have seen, solo RTK surveying with smartphone + GNSS combined with point clouds, AR, and cloud integration is set to bring major change to land improvement sites. The effects are immense: alleviating labor shortages through reduced personnel, improving on-site work efficiency, and enhancing quality through data visualization and sharing. These technologies are not futuristic fantasies but are already available for practical use.

Summary of this article:

• Labor savings: Surveying can be completed by one person, directly reducing personnel and easing labor shortages (personnel can be reassigned to other tasks).

• Efficiency: Dramatically shortens surveying preparation and work time, contributing to shorter schedules and cost reductions (examples exist where 1 km surveying time is reduced to less than one-quarter).

• Visualization: Point clouds and AR enable 3D visualization of the site, improving understanding of design and construction (confirm final images in 3D beforehand).

• Safety: AR technology reduces the need for risky work in hazardous areas, contributing to worker safety.

• Data sharing: Cloud-based instant sharing of survey results automates data organization and deliverable creation (reduces time spent organizing data).

• Ease of introduction: Smartphone + GNSS solutions are low-cost and intuitive, making them accessible to anyone (no special prior knowledge or long training period required).

For example, a solution that easily realizes the smartphone surveying described in this article is [LRTK](https://www.lrtk.lefixea.com/). LRTK is an ultra-compact RTK-GNSS receiver used by attaching it to a smartphone; it comes with an intuitive dedicated app and cloud service. There is no need to carry heavy tripods or special equipment—your handheld smartphone becomes a surveying instrument with centimeter-level accuracy (half-inch accuracy). From positioning to point cloud scanning, photo records, AR display, and data sharing, everything can be completed by one person with a single device, strongly supporting DX on site. The introduction cost is also smaller than conventional instruments, making it realistic for each worker to carry a unit and measure whenever needed. Its ease of use means that even field workers who previously had no relation to surveying can operate it, making it truly a tool for simple surveying. As anyone can perform high-precision surveying without relying on skills or experience, it also helps alleviate knowledge transfer issues caused by veteran technicians’ retirement.

For land improvement associations and agricultural civil engineers, adopting solo RTK surveying is becoming an unavoidable trend, and signs of this are already appearing. National initiatives like i-Construction and the promotion of smart agriculture are tailwinds, and solo surveying has already begun to be introduced in construction and civil engineering sites, contributing significantly to productivity improvements in surveying and as-built management. The demand for efficiency and sophistication through digital technology will only grow. In the future, integration with AI analysis and autonomous construction machinery will further advance DX at land improvement sites. Starting DX on site with the initiative of solo RTK surveying and riding that wave is important.

Why not take this opportunity to experience surveying DX with smartphone + GNSS? By using LRTK, you might be able to start a DX revolution at your site as early as tomorrow. The accumulated efficiencies and labor savings will strengthen regional agricultural infrastructure and greatly contribute to sustainable agriculture. With the new era of surveying opened up by smartphones and GNSS, let us create the future of land improvement together.