Table of contents

• What is RTK?

• Centimeter-level high-precision positioning (cm level accuracy (half-inch accuracy))

• Improved efficiency through real-time measurement

• Single-person surveying and labor savings

• Handles difficult conditions without line-of-sight

• Improved safety

• Data sharing and digital integration

• Cost reduction and return on investment

• Simple surveying with LRTK

• FAQ

In recent years, RTK (Real Time Kinematic) high-precision GNSS positioning technology has become a standard in surveying practice. Especially in advanced countries like the United States, RTK surveying has already been widely adopted as a de facto standard. Why has RTK become so widespread? The reason lies in the many advantages RTK provides. For engineers involved in surveying and construction management, adopting RTK is becoming an unavoidable trend. Actively incorporating advanced technology to improve productivity and result accuracy will become increasingly important. Compared with traditional surveying methods, RTK has superior characteristics in terms of accuracy, operational efficiency, and cost. This article organizes the main benefits of RTK and explains why they have driven its expanded adoption in the U.S. At the end of the article we also introduce simple surveying using a new solution called LRTK.

What is RTK?

RTK is a technology that uses GNSS (Global Navigation Satellite Systems) to perform high-precision positioning in real time. It uses a base station and a rover; the base station sends observed error information as correction data to the rover, correcting satellite positioning errors in real time. As a result, positions that would have errors of several meters in standalone positioning can be determined with surveying-grade accuracy within a few centimeters (a few in).

The advent of RTK-GNSS surveying has greatly improved efficiency for tasks that were previously done with optical total stations or static GNSS surveying (which requires post-processing), and its use has expanded worldwide. In the U.S. in particular, RTK is widely used across construction quality control, land surveying, and even autonomous tractors in agriculture, becoming the mainstream surveying method. For example, using RTK to measure the positions of buried water and sewer pipes or communication cables can reduce the risk of accidental damage during excavation. In agriculture, autonomous tractors use RTK’s high-precision position control to drive straight and perform seeding and fertilization without overlap or gaps. In this way, RTK is being utilized across a wide range of fields, and its usefulness is being recognized in many places.

Centimeter-level high-precision positioning (cm level accuracy (half-inch accuracy))

One of RTK’s greatest advantages is, without doubt, its high positioning accuracy. With RTK’s relative positioning to a base station, extremely high real-time accuracy within a few centimeters (cm level accuracy (half-inch accuracy)) can be achieved both horizontally and vertically. This represents a dramatic improvement compared with conventional standalone GPS positioning (errors on the order of several meters). Not only does this accuracy meet the requirements for many surveying tasks (such as boundary measurements and layout for design and construction), but it has reached a level where measurements that previously required a total station can be substituted by RTK. For example, RTK can provide sufficient accuracy for small-scale land boundary surveys and building layout. The ease of achieving such high precision is a major reason RTK has been embraced by surveyors.

Improved efficiency through real-time measurement

As the name “real-time” implies, another major advantage of RTK is that high-precision position information is obtained immediately on site. Coordinates of points acquired in the field can be finalized on site without having to return to the office for calculations or post-processing. For example, while static GNSS surveying required analysis against control point data after observation, RTK provides results the moment a measurement is taken, allowing immediate transition to the next point.

Compared with total station surveying, RTK also eliminates the need to re-set equipment (to secure line-of-sight), enabling measurement of wide areas in a shorter time. Even over several hectares, continuous point acquisition while moving with an RTK rover can greatly shorten work time without repeating traverse surveys. Vast survey areas that once took several days can sometimes be completed in half a day to one day with RTK. For example, a site of about 100 acres (40 hectares) that required three days with a total station was reported to be completed in less than one day using RTK.

Because positioning results are available in real time, surveyors can verify and check data on site as they work. Incorrect points or missing data can be identified immediately and re-measured as needed. This prevents wasteful rework such as returning to the site later upon discovering data deficiencies.

Single-person surveying and labor savings

The ability to complete surveying work single-handedly after RTK adoption is another important point. Traditional total station surveying required a two-person team—a technician operating the instrument and an assistant holding the prism. With RTK, once a base station is set up, a single surveyor carrying the rover can measure points sequentially. Furthermore, by using public control networks (such as CORS) or internet-based correction services, it may not even be necessary to set up a private base station, and one person can survey using only a rover.

This ability to work alone is a significant benefit for the surveying and construction industries, which face labor shortages and an aging workforce. Single-person operations reduce labor costs and simplify staffing arrangements. In the U.S., where many sites are large, RTK’s efficiency that allows small crews to work effectively was welcomed. As a result, limited personnel can complete many surveys in a short time, directly improving productivity.

Handles difficult conditions without line-of-sight

Another advantage of RTK surveying is that it does not require optical line-of-sight for measurements. Total stations require straight-line visibility between the instrument and the prism, making it difficult to measure in areas obstructed by trees or buildings. RTK can position as long as GNSS satellites overhead can be received, so surveying is possible in forests or narrow urban areas. This removes the need to clear obstacles to secure sight lines or repeatedly re-set equipment.

For example, RTK can smoothly survey in situations such as:

• Boundary surveys within dense forests (no need to secure sight lines)

• Urban areas with high-rise buildings (positioning possible even in building shadows)

• Vast undulating terrain (one base station can cover a wide area)

Thus, RTK excels in places that were difficult to measure previously, greatly expanding the applicable range of surveying. In regions with diverse terrain and environments like the U.S., RTK’s flexibility is highly valued.

Improved safety

The spread of RTK also contributes to improved safety in surveying work by reducing the time spent in hazardous locations. For example, point observations on busy roads can be completed quickly with RTK. Rather than standing on a road for extended periods holding a prism for a total station, rapid measurement and withdrawal reduce safety risks.

RTK combined with drones (UAVs) also enables surveying in areas inaccessible to people. By acquiring terrain data from the air with RTK-capable drones, surveyors do not need to go to dangerous slopes or cliff edges. Aerial photogrammetry using RTK-capable drones can greatly reduce the need to place ground control points (GCPs), cutting preparation work for surveying. Measurements on high or unstable ground can be conducted more safely and efficiently than direct human measurement.

In this way, RTK technology contributes not only to accuracy and efficiency but also to worker safety.

Data sharing and digital integration

Because RTK survey data are all acquired electronically, digital utilization is easy. Point coordinates are recorded on tablets or PCs in the field and can be reflected in CAD drawings or GIS maps immediately.

Moreover, via mobile networks or the Internet, data can be shared between the field and the office in real time. For example, a surveyor can send observed point information from the field to the office via the cloud instantly, allowing colleagues at remote locations to check and process the data.

Such digital integration further improves efficiency, reduces mistakes, and enables smooth information sharing within teams. Reducing analog records and manual input also helps suppress human error. In the U.S., where IT infrastructure is well-developed, cloud-based surveying workflows are common, enabling flexible operations such as immediate sharing of field data for design. RTK-centered digital surveying workflows also contribute to DX (digital transformation) initiatives in construction and surveying industries.

Cost reduction and return on investment

All of the above advantages ultimately lead to significant cost reductions. By using RTK, the same surveying work can be completed more quickly and with fewer personnel, reducing labor costs and daily expenses. For example, if a task that previously required two people for three days can be done by one person in one day, personnel and equipment operating costs are drastically reduced.

Real-time positioning also reduces errors, thereby reducing rework and additional surveys, which contributes to cost savings.

Furthermore, RTK equipment prices have been declining in recent years. High-precision GNSS receivers that were once expensive have become more accessible due to technological progress and market expansion. In the U.S., state CORS networks and private correction services are well established, allowing relatively low-cost access to RTK without having to install expensive private base stations. Many states provide government-operated real-time GNSS reference station services for free or at low cost, making RTK adoption easier for small surveying firms. Nationally deployed CORS (Continuously Operating Reference Stations) have supported RTK proliferation. In Japan as well, improvements in the environment surrounding RTK have steadily progressed through the installation of electronic reference point networks (GEONET) by the Geospatial Information Authority and the start of the Quasi-Zenith Satellite “Michibiki” centimeter-level augmentation service (CLAS). For example, increased demand for RTK outside traditional surveying—such as autonomous tractors in agriculture and drone surveying—has driven mass production and reduced equipment costs. Such infrastructure enhancements have also supported wider adoption.

Overall, the productivity gains and cost reductions from RTK adoption offer a very high return on investment, bringing significant management benefits to surveying operations.

Simple surveying with LRTK

Although RTK offers great advantages, its traditional requirement for specialized, expensive equipment and expertise made some hesitant to adopt it. Recently, however, a new solution called LRTK has emerged to greatly lower these barriers.

LRTK consists of a small RTK-GNSS receiver that attaches to a smartphone and a dedicated app, providing a revolutionary system that enables anyone to perform centimeter-level surveying (cm level accuracy (half-inch accuracy)) easily. By simply attaching a pocket-sized receiver weighing about 125 g to a smartphone, even those with little equipment experience can perform high-precision position measurements and record points. The price is much more affordable than conventional surveying equipment, and it is designed as a field tool that each worker can carry individually. Because it can be taken out and used immediately when needed, tasks that previously had to wait for surveying specialists can proceed quickly.

With LRTK, tasks such as measuring point coordinates, staking out positions, and simple terrain point cloud capture can be done with just a smartphone. Collected data can be uploaded to the cloud on site and shared with the office. In particular, even in mountainous areas or disaster sites without internet connectivity, LRTK can provide stable positioning through its built-in high-precision GNSS functionality (it also supports Japan’s Michibiki “centimeter-level augmentation service (CLAS)”). LRTK was used in field surveys after the earthquake disaster in 2023, where the function that automatically records accurate position and orientation information to photos taken with a smartphone helped efficiently assess damage. In this way, LRTK is expected to make RTK surveying more accessible and simpler, contributing significantly to improved field productivity. Such advanced technologies also align well with i-Construction (reforming construction production processes using ICT) promoted by the Ministry of Land, Infrastructure, Transport and Tourism, and RTK’s penetration into fieldwork in Japan is expected to increase further. For those considering RTK adoption, LRTK is an attractive option.

FAQ

Q: What is RTK? A: A technology that corrects GNSS positioning errors in real time to achieve centimeter-level high-precision positioning (cm level accuracy (half-inch accuracy)). It uses a base station and a rover; the base station observes error information and transmits it (e.g., by radio) to the rover to calculate the rover’s position with high accuracy. It is widely used in surveying and construction.

Q: What is needed for RTK surveying? A: Basically, an RTK-capable GNSS receiver (rover) and a base station (or network service) that provides correction information are required (if using an RTK network, a mobile communication environment is also needed). The base station can be set up privately or you can use government or commercial reference station services (internet-based RTK networks). Radios or mobile lines for connecting the rover and base station are also prepared. Recently, easy-to-use products that combine a smartphone and a small receiver (for example: LRTK) have also appeared.

Q: Can RTK completely replace all traditional surveying equipment? A: RTK can greatly improve efficiency for many surveying tasks, but there are still situations where traditional equipment remains effective. For example, RTK cannot be used where GNSS signals do not reach, such as inside buildings or in tunnels; total stations or leveling instruments are necessary. For ultra-high-precision measurements requiring sub-millimeter accuracy, optical distance measurement or precise leveling may be more appropriate. Therefore, in practice it is ideal to use RTK and conventional methods as appropriate and in combination. Also, RTK’s accuracy is affected by satellite signal reception conditions and atmospheric conditions, so for critical situations cross-checking with multiple surveying methods is recommended.

Q: Why is RTK widespread in the United States? A: As mentioned in the article, RTK’s high accuracy, efficiency, and cost advantages are major factors. In the U.S., with its vast territory, RTK’s efficiency for quickly surveying large areas is especially valued. In addition, many states have established RTK reference station networks, enabling relatively inexpensive access to RTK environments, which has further driven adoption. High labor costs in the U.S. also mean that investments in labor-saving technologies offer significant returns, encouraging adoption. Combined with a population that embraces technological innovation, RTK has become commonplace on surveying sites in the U.S.

Q: What is LRTK? A: A new RTK surveying system used in combination with a smartphone. A small RTK-GNSS receiver is attached to a smartphone and operated via a dedicated app. It enables anyone to perform centimeter-level positioning (cm level accuracy (half-inch accuracy)) easily and offers features such as point measurement, staking, point cloud capture, and AR-based position display. Compared with conventional dedicated RTK equipment, it offers greatly improved portability and ease of use, and is lower cost, aiming for each field worker to carry one unit.

Q: How do I introduce RTK? A: Basically, prepare an RTK-capable high-precision GNSS receiver (rover), a base station, and dedicated positioning software, set them up on site, and use them. Introduction involves purchasing or renting equipment and gaining operational proficiency, but solutions like LRTK that combine a smartphone with a small receiver now allow anyone to start quickly. Consider RTK introduction to match your company’s needs. It is effective to start with pilot projects on small sites to accumulate operational know-how internally.