What is the VRS method? Explain its relationship with RTK clearly in 5 minutes

When researching the term RTK, many people encounter the term VRS method along the way and find it difficult to understand what the actual difference is. In practice, it is easier to organize your understanding by regarding RTK as the overall positioning concept and method, and VRS as one delivery method that makes that RTK easier to use in the field. In particular, whether you set up a reference station yourself each time or receive correction information from a surrounding reference point network greatly changes the operational burden and work efficiency. The Geospatial Information Authority of Japan (GSI) describes network RTK surveying as a method that uses correction information created from observation data of surrounding Continuously Operating Reference Stations (CORS) to efficiently perform cm-level (half-inch-level) surveying in real time, and VRS is one of the representative approaches.

Table of Contents

• Understand the basics of the VRS method first.

• Summarize what RTK is.

• Differences between the VRS method and conventional RTK

• Reasons why the VRS method is used in the field

• Explain the VRS method in simple terms.

• Tasks Suitable for the VRS Method and Points to Note

• Equipment selection with an understanding of the VRS method.

• Summary

Understand the Basics of the VRS Method First

The VRS method is the Virtual Reference Station method. Although the name may sound difficult at first glance, the concept is not that complicated. In conventional RTK, positioning is performed using a combination of a base station installed at a known point and a rover that actually moves and takes measurements. In contrast, the VRS method uses observation data from multiple reference points around the site to generate correction information as if a virtual base station existed near the user, and delivers that information to the rover. In other words, it is an approach that creates conditions similar to performing RTK with a short baseline, without having to place a base station on site each time. In materials from the Geospatial Information Authority of Japan, the Virtual Reference Station method is also described as a system that uses three or more electronic reference stations and aims for positioning accuracy equivalent to RTK with short baselines.

The important point here is not to regard VRS and RTK as opposing, separate things. The understanding that VRS is not RTK is not accurate. Rather, VRS is one of the ways to provide the correction information that makes RTK possible. A common confusion in practice is to treat RTK as a matter of accuracy and to segregate VRS as a communications service. In reality, VRS is closer to a mechanism for stably operating RTK positioning in a networked way, and it becomes clearer if you understand it as one operational mode within RTK. For field personnel, the practical concerns—reduced effort to install base stations, ease of use over a wide area, and quicker start-up of work—matter more than theoretical classifications. In that sense, thinking of VRS as a method that makes RTK more practical and easier to use aligns with real-world practice.

Another reason the VRS method has attracted attention is the basic RTK issue that when measuring with a single reference station placed far away, the influence of errors increases as distance grows. In satellite positioning there are various error factors involved in position calculation, such as satellite orbit errors and atmospheric effects including the ionosphere and the troposphere. If the reference station and the rover are close, they experience similar errors and these can be more easily canceled out, but as they become farther apart the differences in conditions increase and the effectiveness of corrections weakens. The VRS method was developed to compensate for this distance-dependent weakness across the entire network. The idea of virtually creating a nearby reference station is precisely the answer to this problem.

Clarifying What RTK Is

To understand the VRS method, you first need to clarify RTK itself. RTK stands for Real-Time Kinematic, and it is a positioning method that, in addition to signals received from satellites, uses observation data from a reference station to correct errors and obtain high-precision positions in real time. Whereas typical standalone positioning results in meter-level (≈3.3 ft) errors, a major feature of RTK is that, under the right conditions, it can achieve centimeter-level accuracy (half-inch accuracy). For that reason, it is widely used in situations where positional deviations directly affect work quality, such as surveying, construction, as-built verification, machine guidance, infrastructure inspection, agriculture, and autonomous driving support. The Geospatial Information Authority of Japan also describes network-based RTK surveying as an efficient method for conducting centimeter-level surveying (half-inch accuracy).

In RTK, rather than measuring with only a rover, a reference observation point somewhere is required. In conventional operations, you set up your own base station and send its correction information to the rover by radio or similar means to perform positioning. This method is easy to understand and works well in closed sites, but it requires time-consuming preparation such as setting up the base station each time, securing known control points, establishing communications, and checking line-of-sight conditions. Moreover, when the site is large or the survey points are scattered, the distance to the base station and communication conditions tend to become bottlenecks. This is where network RTK, which utilizes data from multiple permanent reference stations, comes in, and the VRS method is a representative example.

In other words, RTK refers to the method of high-precision positioning itself, and VRS is one mechanism for implementing that RTK over a network. To use an analogy, RTK is the overall means of transportation for getting to a destination, and VRS is one operational mode within that. Understanding this difference allows you to explain that, when asked how the VRS method differs from RTK, it is not that they are different technologies but that there is a containment relationship. Many search users are unsure whether VRS is a newer, separate high-precision technology or simply another name for RTK, but from a practical standpoint it is easiest to view VRS as a difference in the correction-delivery mechanism used to perform RTK.

Differences between the VRS method and conventional RTK

The biggest difference between the VRS method and conventional RTK is where and how correction information is generated. In conventional RTK, a physical reference station is placed at or near the site, and correction information is received directly from that reference station. In contrast, the VRS method analyzes data from multiple reference-station networks arranged in the surrounding area and generates correction information from a virtual reference station that is assumed to be located near the user. From the perspective of the mobile station, it appears as if a reference station is nearby, so it is easier to mitigate the disadvantages caused by distance than when relying on a single distant reference station. The Geospatial Information Authority of Japan’s materials also state that, in the VRS method, fixed observation points are treated as virtual points.

This difference directly translates into on-site labor. With conventional RTK, you first need to verify known points, set up a base station, manage antenna height and installation conditions, and choose a location where communications are stable. If the measurement area expands, you may need to relocate the base station or reassess the communication conditions. With the VRS method, if you have an environment that can receive correction information over a communications line, you can greatly reduce the effort required to install a base station. On wide-area sites or jobs where survey points are scattered, this difference directly becomes a difference in work efficiency. The advantage of reducing the time spent installing, monitoring, and removing a base station is especially significant on sites with small crews.

However, the VRS method is not always completely superior. Standard RTK has advantages such as the ability to operate as a closed system with in‑house equipment, relatively lower dependence on communications infrastructure, and the ease of keeping operations confined to the work site. In mountainous areas or locations with unstable communications, or when continuously managing construction within a fixed area, the on‑site base station method can be easier to operate. Conversely, because the VRS method depends on network distribution and communication lines, it can be at a disadvantage at sites with poor communication quality. The important thing is not to treat VRS and standard RTK as a binary choice, but to select based on site conditions, the scope of work, the communication environment, and the difficulty of securing known points.

Furthermore, as a term, there are methods for providing network RTK corrections other than VRS. Therefore, when you see the term VRS by itself, you need to check the context to determine whether it refers to network RTK as a whole or to the specific Virtual Reference Station method. In practice, the term VRS is sometimes used as a colloquial name for network RTK in general, but strictly speaking it is less confusing to understand it as one method within network RTK. If this is left ambiguous, misreading is likely to occur when reviewing specifications or selecting equipment.

Reasons the VRS method is used on site

One reason the VRS method is widely used on site is that it makes it easy to shorten preparation time. For site personnel who want to introduce RTK, high accuracy itself is important, but even more important are whether measurements can be taken immediately at any time, whether the setup process is not overly complex, and whether the workload on operators will become excessive. With the VRS method, you can relatively quickly start work if the appropriate receiving and communication environments are available, without having to install a base station at a known point or assemble radio configurations between devices each time. This ease of deployment is a major advantage not only for professional surveyors but especially for personnel whose primary work is something else—such as construction management or inspections.

The second reason is that it is well suited to wide-area work. For tasks where measurement locations extend linearly or over an area—such as roads, rivers, land development, farmland, and infrastructure patrols—the traditional operation centered on a single reference station tends to make distance and communication range constraints more apparent. Because the VRS method generates corrections from a network of multiple reference points according to the user's position, it is easier to operate over a wide area. Of course, being within communication coverage is a prerequisite, but at least the burden of relocating the reference station to follow the user can be reduced. This aspect is more effective for tasks that involve continuous measurement while moving than for point measurements.

The third point is that it is easier to obtain stable accuracy. When you are far from a single reference station, increasing baseline length weakens the correlation of error sources, which can make it harder to achieve fixes and lead to decreased accuracy. The VRS approach, by placing a virtual reference point near the user, attempts to reproduce conditions similar to short-baseline RTK. As a result, even over wide areas it becomes easier to achieve practically stable centimeter-level operation. From the field operator's perspective, the value is that conditions vary little no matter where you measure, making operational quality more consistent. Not only accuracy but also repeatability and a predictable sense of the work are important, and the VRS approach contributes to those.

Explain how the VRS method works in an easy-to-understand way

To put the mechanism of the VRS method as simply as possible: first, multiple reference stations deployed across a wide area continuously observe satellite signals. Those observation data are gathered at a processing server, and the error trends across the region are modeled. Next, when the user mobile station sends its approximate position, correction information is generated as if a virtual reference station existed nearby and returned to the mobile station. The mobile station receives that correction information and combines it with its own observations to compute a high-precision position. An explanation by a certain receiver manufacturer likewise shows this flow: the mobile station sends its position to the server, the server models the systematic errors at that position and returns corrections.

What's important here is that the virtual reference point does not physically exist. It is merely a reference point computed from the information of multiple reference stations. However, from the rover's perspective it can receive corrections under conditions similar to those of having a nearby base station, so as a result it is easier to achieve performance close to that of short-baseline RTK. The term "virtual" here does not mean fictitious or imprecise; it means a reference point calculated based on network analysis. If this nuance is misunderstood, some people may worry that the virtual nature implies lower accuracy, but the intention is actually to improve accuracy and stability.

Also, communication is important in the VRS method. In the conventional base-station radio approach, corrections are sent directly from the base station to the rover, but with VRS corrections are generated on the network side, so the rover requires a communications environment capable of interacting with the server. This may look like just another configuration item to users, but in practice it affects initialization time, correction outages, and the ease of maintaining a fix. Therefore, when implementing a VRS solution, it is important to check not only receiver performance but also communication stability, the communication conditions in the work area, and the ability to maintain connections while moving. High-precision positioning is not determined by satellites alone; it depends on the entire system, including corrections and communications.

Tasks Suited to the VRS Method and Points to Note

The VRS method is particularly suited to tasks that require agile surveying over wide areas. For example, for site condition checks that visit multiple points in a short time, as-built verification along linear features, routine infrastructure inspections, and positioning work carried out while moving between multiple sites, VRS is more efficient than setting up and dismantling a base station each time. The setup before starting positioning work is short, and because it’s easy to use with the same approach even when moving between sites, it has the advantage of making workflows easier to standardize. It’s a good fit not only for specialist surveying teams but also for construction and maintenance personnel who handle high-precision positional information.

On the other hand, there are also caveats. The most apparent is reliance on communications. Because the VRS method uses a communications link to deliver correction data, performance may be insufficient in areas outside communications coverage or in unstable areas. In locations where satellite reception conditions are inherently poor—such as mountainous areas, around tunnels, beneath elevated structures, or in densely built-up areas—VRS is not a cure-all. If satellite visibility is poor, the observation conditions themselves are disadvantaged even before any corrections. Therefore, even if you choose the VRS method, you must separately evaluate sky openness, obstruction/shielding conditions, susceptibility to multipath, and communication quality. Many causes of RTK failing to achieve a fix are not the method name itself but the satellite environment and the communications environment.

Another point of caution is that using the VRS method does not mean you should unconditionally trust all positioning results. In high-precision positioning, basic procedures such as understanding the coordinate system, checking consistency with site references, confirming initialization status, verifying by re-measurement, and matching with known points are indispensable. In particular, for work that affects subsequent processes—such as construction or as-built measurements—you should not be reassured solely because a Fix has been achieved; operations must confirm positional reproducibility and agreement with known points. VRS is a convenient method, but its convenience can lead to skipping verification steps and causing rework that could have been avoided. Designing operational rules is as important as understanding the method.

Equipment selection based on an understanding of the VRS method

When considering using the VRS method, what should you look at when selecting equipment? First and foremost, what you need is not simply equipment labeled as VRS-compatible, but whether it can be configured to operate RTK stably on-site. You need to judge satellite reception performance, the method of receiving correction information, communication means, ease of initialization, stability of maintaining a fix, and ease of recording and verification. VRS is a method of providing corrections, and if the receiving side's performance and operability are insufficient, it may be usable in theory but difficult to handle in practice. Especially if you think of it as a tool that field personnel use every day, the complexity of settings and ease of verification are as important as accuracy.

The next thing to consider is the operational mode that suits the site. If you plan to use it over a wide area in regions where continuous communications are stable, the VRS approach can be highly effective, but if the area includes many places with unstable communications, you should also consider other correction methods or a reference-station approach. Also, the required performance differs depending on whether the measurement target is point-centered or whether you handle positions continuously while walking. For single, one-off observations you can often just wait a bit for a fix, but for continuous use while moving, interruptions to corrections or difficulties in reinitialization directly translate into operational stress. It’s important to choose not only by method but from the perspective of matching the workflow.

In recent years, demand has grown not only for specialized equipment but also for combining high-precision positioning with more familiar devices. On-site, there are increasing situations where not only dedicated surveyors but also construction managers, inspection personnel, and maintenance staff want to use location information. Therefore, after understanding the concepts of VRS and RTK, it is important to consider ease of operation, portability, and ease of implementation. High-precision positioning is no longer just for a few specialists; it is spreading as a practical tool that supports daily on-site decision-making. For that reason, it is more valuable to determine which method fits your work than to memorize difficult theory.

Summary

The VRS method uses observation data from multiple reference station networks to generate correction information as if a virtual reference station were established near the user.

RTK, on the other hand, is the method itself that uses that correction information to perform real-time, centimeter-level (half-inch accuracy) high-precision positioning.

In other words, it's easier to understand VRS not as a technology separate from RTK, but as a representative scheme for operating RTK in a networked configuration.

Compared with conventional RTK, which requires setting up a local reference station each time, the VRS method has the advantage of reducing setup effort and being better suited to wide-area operations.

On the other hand, considerations for communication environments and satellite reception conditions are indispensable, and because it is convenient, it is especially important to carry out basic checks carefully.

For practitioners searching for "rtk", what they really want to know is likely not the definition of the term itself but whether it is easy to use at their own site. From that perspective, the VRS method can be seen as an approach that makes high-precision positioning easier to apply in practical work. It is especially valuable on sites where there is little time to set up a reference station, on sites involving movement, and where personnel who are not dedicated surveyors need to handle location information. If you want to bring high-precision positioning into the field more easily, it is important to choose a user-friendly equipment configuration based on the VRS method and the RTK mechanism. As one option, using an iPhone-mounted GNSS high-precision positioning device like LRTK can make it easier to translate the specialized-equipment approach into everyday operations. For practitioners who need to quickly acquire, confirm, and record positions on site, making high-precision positioning usable in daily work will become increasingly important.