7 Measures to Try When RTK Positioning Is Unstable

RTK is an extremely effective positioning method when you need to quickly obtain coordinates in the field. However, in actual operations you often encounter problems such as "difficulty achieving a fixed solution," "sudden shifts after a once-stable solution," or "measurements at the same location not settling," which can prevent you from achieving the expected work efficiency. This instability is not caused solely by the equipment itself. It is usually the result of multiple factors overlapping: sky visibility, surrounding reflection environment, reception conditions of correction data, installation method, settings, observation procedures, and so on. In other words, rather than attributing the cause to a single factor, systematically isolating field conditions and operating procedures one by one is the quickest route to stable positioning. This article organizes and explains seven countermeasures that field personnel can easily try when RTK positioning is unstable, along with ways of thinking about their causes.

Table of Contents

• What does it mean for RTK positioning to be unstable?

• Countermeasure 1 Reassess the observation site and secure an unobstructed view of the sky

• Countermeasure 2: Adjust the antenna installation method and the way you hold it

• Countermeasure 3: Check your communication environment to reduce interruptions in correction data

• Countermeasure 4 Reconfirm correction information settings and connection conditions

• Countermeasure 5: Isolate misconfigurations in the coordinate system and height settings

• Countermeasure 6: Reinitialize and review how observation time is taken

• Countermeasure 7: Identify the cause by checking verification points and logs

• Summary

What does it mean for RTK positioning to be unstable?

The phrase "RTK positioning is unstable" is used in the field with a fairly broad meaning. Sometimes it refers only to a condition in which a fixed solution cannot be obtained, while other times it includes cases where a fixed solution is achieved but the coordinates fluctuate. The first important thing is to rephrase the phenomenon you're experiencing in concrete terms. For example, the points you need to check vary depending on whether initialization takes a long time, whether it easily drops from a fixed solution to a different solution, whether the values keep fluctuating by several centimeters (a few inches), or whether you get clearly different coordinates.

What often happens on-site is that unstable communications and poor reception environments are confused. Cases where correction data is interrupted and the positioning solution cannot be maintained, and cases where positioning itself is disturbed by reflections from surrounding structures, may look similar. However, the remedies are not the same at all. In the former, you should inspect the communication path and connection conditions, while in the latter you need to change the observation position or reconsider the antenna placement.

Furthermore, even if positioning results appear unstable, it may actually be simply that the coordinate system or height settings do not match the site standard. In this case, even if the equipment is measuring stably, it will appear offset when compared with reports or drawings, causing users to feel that "the positioning is jumping around." In other words, for RTK instability it is important to isolate whether the problem lies in reception quality, correction quality, installation quality, configuration quality, or operational quality. With that premise in mind, checking the following seven countermeasures in order will make it considerably easier to identify and remedy the cause.

Countermeasure 1: Reassess the observation location and secure an unobstructed view of the sky

The most basic and, at the same time, highly effective step is to reassess the observation location. Because RTK receives signals from satellites and improves accuracy by using their differences, how open the sky is directly affects stability. Signals are easily blocked or reflected near building walls, directly under trees, close to slopes or embankments, in areas where heavy machinery or vehicles are concentrated, and around metal fences. This causes the combination of satellites you can receive to become unstable, making it difficult to maintain a position solution.

On site, there are situations where you can't help but want to measure directly above the target point. However, it is not uncommon for sky visibility to change significantly with just a few steps. Especially in locations with tall structures nearby, it is important to first look for a place where you can measure stably, rather than focusing on the exact point position. Simply confirming stability from a slightly offset position before moving on to the main measurement can sometimes improve initialization time and variability.

There are also sites where the surrounding work conditions change between the morning and the afternoon. Areas that were clear in the morning can become lined with large vehicles, and temporary materials may be stacked up by the afternoon. If something was stable yesterday but is unstable today, check whether the surrounding environment has changed before assuming equipment failure. RTK is strongly affected by external environmental conditions, so you cannot always take measurements under the same conditions every time.

In practice, it is effective to first verify a baseline stable condition in an open area and then compare that with the condition at the target location. If it is stable in the open area but unstable at the target location, the cause is more likely the field environment than the equipment. Conversely, if it is unstable no matter where you move it, you should suspect other factors such as communications, configuration, or initialization procedures. Changing the observation location as an initial measure may seem simple, but it is very important for isolating the cause.

Countermeasure 2 Adjust the antenna installation method and how you hold it

RTK stability is affected not only by the antenna’s performance but also by how it is installed. In practice, the more hurried you are, the more likely installation and holding will become sloppy, and that shows up as positional variability. For example, conditions such as a tilted pole, a mounting surface that is soft and moves subtly, holding it so body sway is transmitted, or being too close to nearby metal components all negatively affect the stability of the readings.

Especially during handheld operation, users themselves can degrade the antenna's reception environment. When the body is heavily tilted or the posture is too close to a building wall, reception becomes more prone to directional bias. In addition, if you try to measure immediately after moving, the solution may not yet be stable. Even if you think you have stopped, small body movements or pole sway can remain, causing measurements to be recorded before the observations have settled.

Care is required even when using it in a fixed installation. If the tripod or pole is not firmly secured, small movements can occur due to wind or ground vibrations. It is precisely because RTK is highly accurate that such slight movements cannot be ignored. On unpaved ground or on gravel, the feet can sink easily, so even if it looks stable it may actually be shaking. If you feel instability on site, don’t rely solely on the receiver screen; it’s important to first visually check the installation.

Also, the handling of antenna height is another easy-to-overlook point. Errors in antenna height input do not cause positioning instability itself, but they undermine the consistency of the results. If you’re measuring at the same location yet only the height doesn’t match, or if differences appear from day to day, you should check this together with variations in installation methods. In other words, stable positioning operation is not simply about receiving satellites well, but about creating a state in which observations can be made under the same conditions every time. Keep the antenna vertical, suppress unnecessary sway, and install it away from surrounding objects. Simply enforcing these basic actions can significantly reduce practical instability.

Countermeasure 3: Check the communication environment to reduce interruptions in correction data

In RTK that uses network-based corrections, the stability of the communication link is directly tied to the stability of positioning. Even if satellite signal reception is good, if reception of correction data is unstable, maintaining a fixed solution becomes difficult. In the field there are cases where “the satellites are being tracked but it’s not stable,” and in many of these cases the cause is an intermittent flow of correction data. Because users who only look at the receiver screen may not notice this, it is important not to postpone checking the communications side.

Communication conditions tend to deteriorate in mountainous areas, on the valley side of developed land, in locations close to underground spaces, in places surrounded by buildings, or during time periods when the communication load around the site is high. Mobile communications cannot always maintain the same quality, and delays or momentary dropouts can occur depending on site conditions. If correction data updates are disrupted, the solution becomes difficult to maintain, causing it to drop from a fixed solution or to take an excessively long time to initialize.

A useful countermeasure is first to move to a position where the connection is stable and see if that improves things. Moving just a few meters (a few ft) can sometimes improve reception. Also, how you hold the device or where you place it affects communication quality. Situations where the device is in the shadow of your body or a vehicle, kept in a metal case, or placed near materials can degrade the connection. Communication failures are invisible and therefore tend to be overlooked, but they have a very large impact in practical RTK work.

Furthermore, as part of the field workflow, rather than beginning the actual observation immediately after establishing the correction connection, it is effective to monitor the solution state for a certain period. Being connected is not the same as continuously receiving corrections in a stable manner. If the connection has only been established briefly, values tend to spike during the actual measurement. When positioning is unstable, do not assume it is a satellite problem; always check whether correction data is flowing without interruption. Checking communications may seem unremarkable, but it is an important basic step to prevent re-measurements or having to return to the site.

Solution 4: Reconfirm Correction Information Settings and Connection Conditions

Even if correction data is being received, if the settings are not correct it will not lead to stable positioning. A surprisingly common situation on site is that the connection destination or correction conditions remain from the previous job and do not match the current site conditions. Users tend to think, "It worked yesterday, so it'll be fine today," but when the site changes the required conditions can also change. Even if the equipment itself is functioning properly, a mismatch in settings alone often appears as unstable behavior.

For example, it is essential to check whether the device-side settings are appropriate for the correction method being used, whether the necessary items are correctly reflected after the connection is re-established, and whether the solution has sufficiently stabilized before starting observations. In particular, at sites where equipment is shared among multiple users, settings changed by a previous user may remain. Even if you believe you haven't touched anything, changes in connection conditions or observation mode can affect stability.

Also, it’s dangerous to be reassured simply because corrections are being applied. What matters is not whether corrections are being received, but whether those corrections are functioning appropriately for the current positioning conditions. Even if the status display appears normal at first glance, the system may be repeatedly reinitializing internally or performing positioning without stabilizing. On site, make a habit of checking the display items together—solution type, correction reception status, continuity of updates, and whether stability is achieved over time—to reduce oversights.

Checking settings may feel tedious, but it is extremely efficient for isolating causes during instability. If changing location doesn't help, communications seem fine, and the installation is stable, returning to the settings is the standard approach. Including rebooting and reconnecting, resetting the correction reception process to a completely clean state and then checking it can sometimes yield improvement. In practice, rather than chasing complicated theories, an attitude of verifying, one by one, whether the conditions are properly set for use at the current site leads to stable operation.

Countermeasure 5: Isolate mistakes in coordinate system and height settings

Among the issues reported as RTK instability, many cases are actually caused by mistakes in the coordinate system or height settings. For example, measurements taken repeatedly at the same location may fall within a close range yet fail to match known control points or drawings. In such cases users feel that “positioning is unstable,” but fundamentally it may not be that the positioning values are unstable — rather the reference used for comparison may be different. If this is misjudged, one will keep blaming the reception environment indefinitely.

Particular attention should be paid to cases where the horizontal position appears to be correct but only the height is off. There are multiple ways of handling height, and if the height reference required on site and the reference used by the device do not match, a consistent offset will persist. Because this offset is repeatable, it can give the impression that “the height is wrong every time” even though the equipment is stable. What is needed here is first to determine whether the issue is variability or a consistent offset. If it is variability, suspect reception or installation problems; if it is a consistent offset, suspect configuration or reference issues.

The same applies to planar coordinates. If the coordinate system used in the site drawings or existing deliverables does not match the terminal's settings, they can appear to be significantly offset. Moreover, because the coordinate offset is stable, continuing to measure without noticing it can lead to major rework in later stages. To improve RTK stability, it is necessary not only to maintain a fixed solution but also to configure output conditions that align with the site's reference.

Therefore, when positioning seems unstable, checking at known points or verification points is effective. If the offset is in the same direction and of the same magnitude, a setting/configuration issue is more likely than an environmental factor. Conversely, if the direction and amount differ each time you measure, you should prioritize suspecting reception or installation problems. To make decisions on site more quickly, it is important to consciously check whether “the values are scattered” or “the values are consistent but do not match the reference.” Simply having this perspective makes it less likely that you will get the order of countermeasures wrong.

Countermeasure 6: Review Reinitialization and Observation Time Handling

With RTK, when the solution becomes unstable, it can be faster to reinitialize once rather than forcing yourself to keep measuring as is. On site, in the rush to get the job done, people tend to try to use it even when the solution looks questionable. However, if you continue recording while initialization is disturbed or while switching between a fixed solution and another solution, you won't later be able to tell which points are reliable. That will require re-surveying and will end up costing you time.

When measurements are unstable, it is important to stop observing once, adjust the orientation and environment, and choose to reinitialize. Immediately after moving or right after a sudden change in the surrounding environment, it may not stabilize immediately. If you try to take measurements by seizing the brief moments when the display looks better under those conditions, reproducibility will be low. For tasks that require accuracy, especially those involving height, it is ultimately safer to wait a little until the values settle.

Also, the way observation time is handled is another point to review. Rather than adopting a value that appears only briefly, simply switching to a procedure that records values after confirming stability over a set period can reduce points with large variation. In practice, it is ideal to allow sufficient confirmation time for each point, but there is a trade-off with workload. Therefore, varying the thoroughness of observation according to the importance of each point — for example, checking important points for longer and auxiliary points for shorter periods — is also effective.

Furthermore, if instability occurs repeatedly, it is also important not to stick around that spot for too long. Flexible judgments—slightly changing position, waiting until surrounding conditions change, or measuring from another point first—help maintain the efficiency of the whole site. RTK’s strength is the ability to measure quickly, but that presumes stability. Forcing speed when conditions are unstable reduces the reliability of the results and ultimately becomes inefficient. Reinitialization and reviewing observation times are typical countermeasures of the “more haste, less speed” variety.

Countermeasure 7 Identify the cause by checking verification points and logs

When positioning is unstable, the thing you should avoid most is jumping to conclusions about the cause based solely on intuition. Rules of thumb such as "the signal seems bad today" or "this spot is always no good" are important, but on their own they won't lead to reproducible improvements. What helps is verifying with test points and reviewing positioning logs. Keeping a small reference point on site makes it easier to separate environmental factors from configuration factors.

When checking at a verification point, it’s important not to just take a single measurement but to observe several times over a period to grasp the trend. If the value returns to nearly the same reading each time, the positioning may be stable. Conversely, if readings scatter from run to run, one of the reception environment, communications, installation, or initialization may be disturbed. Furthermore, if verification points in open areas are stable but only the problematic locations are unstable, you can narrow the cause down to environmental factors. Creating such comparison points makes it clear which countermeasures should be prioritized.

Checking the logs is also effective. By looking at information such as which time period became unstable, what the reception status of corrections was, how the solution's state transitioned, and what the satellite reception status was, you can see things that cannot be discerned from on-site recollection alone. For example, even if the operator feels it "suddenly shifted," the logs may show that the solution had been unstable for several minutes beforehand. In that case, you can infer that the cause was not a momentary fault but a reception environment or communication condition that gradually deteriorated.

What matters in practice is not immediately pinning down the cause when a problem occurs, but keeping records in a way that prevents the same failure next time. Even a brief note of where, when, and under what conditions instability occurred will reveal site-specific patterns. As a result, you will know in advance which locations to avoid, the measurement order, and the time required to confirm stability. Stable RTK operation is strengthened not by leaving it to the equipment, but by accumulating field knowledge. Validation points and log checks are the foundation for that.

Summary

When RTK positioning is unstable, rather than immediately suspecting equipment failure, it is important to review in the following order: the observation site, antenna installation, communication environment, correction settings, coordinate system consistency, reinitialization procedures, and verification using check points and logs. In many cases, instability is not caused by a single factor but by the accumulation of several small conditions. Therefore, fixing only one thing may not fully resolve the problem. Conversely, by isolating and addressing each factor one by one, field reproducibility can be steadily improved.

What matters for field personnel is not measuring in a perfect environment every time, but being able to recover correctly when things become unstable. Confirm the reference conditions in an open area, set up carefully, do not neglect corrections and communications, check the consistency between settings and references, and if something seems suspicious do not force a recording—reinitialize instead, and preserve the cause with verification points and logs. If this workflow is established as the standard on-site procedure, the usability of RTK will change dramatically.

Also, if you want to make high-precision positioning more accessible and more mobile on site, device configuration and ease of operation are also important. In situations where you want daily positioning checks, coordinate acquisition, and position setting to proceed more smoothly, using an iPhone-mounted GNSS high-precision positioning device like LRTK makes it easier to balance on-site usability with high-precision positioning. If you are struggling with RTK instability, reviewing your equipment and operational methods from the perspective of whether they can be operated stably in the actual field—not just looking at accuracy figures—can be the first step toward better results.