How to Improve RTK-GPS Accuracy? 7 Ways to Reduce Positioning Errors

When aiming to stably improve the accuracy of RTK-GPS, what many field practitioners worry about first is not so much differences in the equipment's own performance as how much the error can be reduced in the actual field. Even positioning methods that are theoretically high-precision can yield different results on site because various factors overlap—surrounding buildings, trees, terrain, communication conditions, installation methods, and how observations are conducted. Therefore, improving RTK-GPS accuracy is not a problem that can be solved simply by using higher-performance equipment.

Many readers searching for "RTK GPS accuracy" are looking for concrete, field-ready improvements rather than desk-based explanations. Positioning errors can be sufficiently suppressed if their causes are correctly isolated. Conversely, if work proceeds while causes remain unclear, re-measurements and rework increase, and the benefits of high-precision positioning are diminished.

In this article, after organizing the main reasons why RTK-GPS accuracy fluctuates, we explain seven practical methods that can be easily implemented in the field to reduce positioning errors. The content is summarized from perspectives directly related to practical work, so those using RTK-GPS for tasks such as surveying, construction management, as‑built verification, stakeout/positioning, and site condition assessment should use this as a reference for daily operational improvements.

Table of Contents

• Reasons why RTK-GPS accuracy is unstable

• Method 1: Prioritize an observation environment with an unobstructed view of the sky

• Method 2: Properly prepare the antenna installation conditions

• Method 3: Maintain Stable Reception of Correction Information

• Method 4 Carefully carry out initialization and verification of fixed solutions

• Method 5 Improve the reliability of measurements through observation time and repeat observations

• Method 6 Use control points and known points to perform on-site corrections

• Method 7: Standardize work procedures to reduce human error

• Operational considerations for improving RTK-GPS accuracy

• Summary

Reasons Why RTK-GPS Accuracy Is Unstable

RTK-GPS is a system that achieves high-precision positioning by combining signals received from satellites with correction information. However, that precision is not always consistent. The reason results vary from site to site is that the positioning conditions are not the same every time.

First and foremost is the satellite signal reception environment. In locations where the sky is not sufficiently open, not only does the number of satellites that can be received decrease, but signals can reflect off buildings, slopes, trees, and so on, causing reception along paths different from the direct wave. These reflections destabilize positioning measurements, and even if it appears that a measurement is being obtained, they can cause the reported position to gradually drift.

Another aspect that is easy to overlook is the antenna’s installation condition. The higher the accuracy of an RTK‑GPS, the more likely that slight tilts or errors in height settings will appear in the results. Factors such as the equipment not being securely fixed, the pole not being vertical, or the antenna height not being entered correctly can each, on their own, become sources of error.

Furthermore, the reception quality of correction information also has a major impact on accuracy. RTK-GPS is not a standalone positioning method; it only achieves high precision after receiving correction information. Therefore, in environments with unstable communications or conditions where corrections are likely to be interrupted, a fixed solution may not be maintained or the solution status may change, resulting in unstable positioning.

Also, the operator’s judgment is important. Operational habits—such as taking observations without fully confirming that a fixed solution has been obtained, measuring only once and treating it as definitive, or proceeding without checking against known points—will ultimately lead to increased errors. In other words, RTK-GPS accuracy becomes stable only when equipment, environment, communications, procedures, and people all come together.

Once you understand this premise, ways to improve accuracy also become clear. The key is to implement measures tailored to each cause. From here, we will go through seven methods, in order, that are easy to implement in the field and highly effective.

Method 1: Prioritize observation environments with an unobstructed view of the sky

When improving the accuracy of RTK-GPS, the first thing to review is the observation location. No matter how high-precision the positioning method, if you cannot reliably receive the satellite signals themselves, it cannot deliver its true performance. When you notice large errors on site, before suspecting equipment failure or configuration mistakes, the first thing to check is the sky visibility.

Ideally, the environment should offer a wide, unobstructed view of the sky. Locations with few tall buildings nearby, not covered by tree branches and leaves, and not influenced by slopes or retaining walls make it easier to receive satellite signals unobstructed. In such environments, the number of received satellites tends to be stable, and it is easier to secure a geometrically favorable configuration, which leads to greater solution stability.

Conversely, accuracy tends to drop in locations where part of the sky is obstructed. For example, at the edge of buildings, near material storage yards, under trees, at the bottoms of valley-like terrain, and near bridges, satellite signals are easily blocked or reflected. In particular, in places where the sky directly overhead is visible but the surroundings are enclosed, it may appear as if measurements are being taken when in fact they are not stable. Extra caution is needed in situations where an operator concludes, "It's receiving, so it should be fine."

On site, you sometimes have to measure very close to obstacles. Even in such cases, without being overly particular about the exact observation point, simply shifting your position slightly can improve reception conditions. For example, moving a little away from a wall, relocating to a gap in the canopy, or avoiding the shadow of materials or heavy equipment—small adjustments like these can improve accuracy. When necessary, it can also be effective to take auxiliary observations from a safe, unobstructed position and determine the location while clarifying the positional relationships.

Also, satellite visibility changes with the time of day. Even at the same location, the solution may be stable at some times and unstable at others. When it is difficult to achieve the required accuracy on site, it is important not only to suspect the equipment but also to consider re-observing at a different time. In particularly challenging environments, simply adjusting the observation timing can make it easier to reach a fixed solution.

If you want to increase accuracy, it's essential to first develop the habit of asking, "Should I really be measuring here?" RTK-GPS is not foolproof, but if you choose an appropriate observation environment it can deliver high stability. Simply looking around before starting work and prioritizing a spot with an open sky can significantly reduce the likelihood of positioning errors.

Method 2: Properly Prepare Antenna Installation Conditions

As a countermeasure for RTK-GPS errors, the antenna installation method is something that surprisingly makes a difference in the field. In high-precision positioning, even a slight tilt or difference in height directly translates into position errors. Even if satellite signals and correction information are stable, accuracy will not improve if installation conditions are disturbed.

First and foremost, keep the antenna as vertical as possible. Even a slight tilt of the pole can shift the measured point on the ground more than you might imagine. Especially when you're rushing observations or working on poor footing, what looks straight may actually be tilted. Even for short observations, never skip confirming that the antenna is vertical.

The next important point is managing antenna height. Antenna height is the height from the survey point to the antenna’s reference point, and if this value differs the calculation results will change. Errors in the input value, unit mix-ups, or misunderstandings about the measurement location are all direct sources of error. Moreover, because this type of mistake is difficult to detect later, on-site verification is extremely important. It is necessary to measure in the same way each time, record using the same procedures, and perform a recheck after data entry.

The stability of equipment mounting should not be overlooked. If tripods or poles are not firmly set, they can shift slightly during observations. Wind, soft ground, and hand-held movement can all introduce errors. Especially for longer observations, whether the equipment is stable can determine the results. On steep slopes or in muddy conditions, footing can be less secure than it appears, so prioritize installation stability.

Also, metal objects or large reflectors near the antenna can adversely affect the signal environment. Where fences, guardrails, vehicles, heavy equipment, steel frames, containers, and similar objects are nearby, satellite signals are more likely to be reflected, which can cause reception to become unstable. Therefore, it is important to choose the installation location not just based on visible sky but also considering the surrounding environment of the antenna.

In practice, there are many situations where the care taken with installation conditions affects results more strongly than differences in equipment performance. If you want to minimize errors, don't skimp on the tens of seconds before measuring. Even just checking the four points—vertical alignment, secure mounting, antenna height, and surrounding reflections—each time will greatly improve the repeatability of observations.

Method 3 Maintain Stable Reception of Correction Information

RTK-GPS can achieve high accuracy because it uses correction information in addition to satellite signals. If this correction information becomes unstable, it can become difficult to obtain a fixed solution, or positioning that had been stable may be lost. In other words, to improve RTK-GPS accuracy, it is essential to ensure conditions that allow stable reception of the correction information.

On-site, it's common to focus only on the aerial environment and delay checking the communications environment. However, in locations where correction information is unstable, positioning results will also become unstable. In areas with poor communications, correction updates are delayed and the solution's state tends to fluctuate. Even if positioning appears to continue on the surface, caution is necessary because internal stability may be declining.

Therefore, before starting work, it is important to confirm that correction data can be received around the site without problems and to identify locations where reception is likely to be interrupted. Communication conditions can vary by location even within the same property. Areas in the shadow of buildings, behind slopes, around structures close to underground spaces, and mountainous areas can make it difficult to receive correction data. If you continue observations in such places despite this, you may fail to obtain a fixed solution or be unable to maintain one.

If reception of correction information is unstable, it may improve simply by moving the observation position slightly. This is because, like satellite signals, the communication environment is also affected by location. Also, walking the entire site before starting work to check where reception is stable and where it becomes unstable will reduce uncertainty during actual operations. This is not merely a preliminary check, but preparation to maintain work quality.

In addition, it is important not to begin observations immediately after receiving correction information, but to start work only after confirming that the condition has stabilized. Even if the display shows a connection, it can take some time to reach a stable fixed solution. If you rush to start observations, you may adopt those initial unstable values.

At job sites, people tend to lump all causes of failed measurements together as "poor accuracy," but a significant portion of those causes are related to communication issues. Simply making it a habit to check whether correction information is being received reliably can reduce unnecessary re-measurements and judgment errors. Improving RTK-GPS accuracy is achieved not only by the satellites but also by maintaining the quality of the correction information.

Method 4 Carefully perform initialization and verification of fixed solutions

With RTK-GPS, simply receiving signals is not enough. What matters is whether the solution state is stable. Especially immediately after initialization or right after movement, you should not immediately trust the displayed numbers; you need to confirm that a fixed solution has been properly obtained. Carefully doing this alone can greatly prevent the introduction of positioning errors.

A common situation in the field is to continue observations simply because the equipment is running, numbers are being displayed, and a position is shown. However, with RTK-GPS, the presence of numbers does not mean the system is in a high-precision state. If observations are made while the solution is still float, the expected accuracy may not be achieved, and there can be large variations between survey points.

Therefore, before starting observations it is important to confirm that the solution is fixed and to check that this state remains stable for a certain period of time. Immediately after the solution switches to fixed, the values may not have settled yet. Rather than finalizing immediately just because the display shows "fixed", simply waiting a little to verify the stability of the numbers will increase the reliability of the adopted value.

Also, it is important to check the solution status each time you move. Just because you once obtained a fixed solution does not mean the same level of accuracy will be maintained thereafter. The solution status can change for various reasons, such as passing near obstacles, changes in communication conditions, or changes in the configuration of satellites being received. If you fail to check after moving or changing measurement points, you may continue working without noticing that the accuracy has degraded partway through.

It's also important not to overlook situations that require reinitialization. If you notice signs such as values jumping unnaturally, taking an unusually long time to converge to a fixed solution, or large discrepancies with known points, you should reinitialize the state rather than continuing as is. If you rush to carry on, later stages may fail to reconcile and tracing the cause will take extra time.

RTK-GPS is a highly efficient positioning method, but prioritizing speed too much sacrifices accuracy. Conversely, adding just a little more care to initialization and to the verification of a fixed solution greatly improves the stability of the results. In practice, determining whether that single point in front of you is truly usable is far more important than measuring it quickly.

Method 5 Enhancing the Reliability of Values through Observation Time and Re-Observation

When trying to improve the accuracy of RTK-GPS, people tend to focus on positioning methods and equipment settings, but in practice the way observation time is allocated and the approach to re-observation are also very important. In particular, an operation that determines important points by observing them only once for a short time, while seemingly efficient, is prone to overlooking errors.

First, be aware that observed values can have momentary fluctuations. Even with a fixed solution, small variations are always present. Therefore, instead of immediately accepting the first displayed value, observe how the value changes for a few seconds to a certain period of time; this makes it easier to detect abnormal oscillations or instability. Even if only for a short time, cultivating the habit of identifying a settled value directly leads to improved accuracy.

For important measurement points, re-observing them after some time is effective. For example, after the initial observation, simply measuring the same point again after doing other tasks can confirm the consistency of the values. If the two results match closely, confidence in the accepted value increases. Conversely, if a large discrepancy appears, you can identify early on that there may be problems with the environment or procedures at that point.

The effect of re-observation is not limited to mere confirmation. It is also effective as a means to reveal sources of error on site. For example, if measurements were good at first but become unstable when taken at different times, satellite geometry or the surrounding environment may be influencing the results. Alternatively, if the values show greater variability when the operator changes, it can be inferred that there are human differences in setup or operation. In this way, re-observation is both a quality check and a way to gain clues for operational improvement.

Also, it is necessary to adopt an approach that varies the thoroughness of observations according to their importance. Rather than treating every point the same, you should allocate longer observation times and perform rechecks for points that strongly affect downstream processes, serve as reference points, or cannot tolerate positional deviations. Conversely, for points whose purpose is simply to obtain a general overview, it may be acceptable to prioritize efficiency. By applying such gradations, it becomes easier to balance overall work efficiency and quality.

What matters for practitioners is not to confuse measuring quickly with measuring carelessly. By allowing a little observation time and incorporating re-observations at key points, missed errors can be greatly reduced. The true value of RTK-GPS lies in obtaining high-precision measurements quickly, but that presupposes the composure to assess which values to accept.

Method 6: Use reference points and known points to perform on-site corrections

To reliably improve RTK-GPS accuracy in the field, it is essential not only to take measurements but also to compare them against known positions. No matter how stable the positioning results may appear, without a verification mechanism it is difficult to determine whether they are truly correct. Using control points or known points for verification and correction is therefore effective.

First and foremost, before starting work you should observe known points and determine whether there are any on-site deviations. If alignment with the known points is good, it becomes easier to judge that the day's reception environment, correction information, and equipment settings are generally acceptable. Conversely, if there are large deviations at the known points, you cannot expect accuracy by measuring unknown points as is. At that stage it is important to investigate the cause and review the environment and procedures.

The value of verifying known points is not limited to a simple check at the start. By verifying them during work and at the end, you can grasp changes that occur over time. Even if conditions are good at the start, environmental conditions can change in the afternoon and small deviations can gradually widen. To avoid overlooking such changes, the practice of returning to known points at each milestone is effective.

It is also important to adopt the approach of correcting positional relationships to match site-specific conditions. RTK-GPS is highly accurate, but there are situations that require alignment with existing site coordinates or local reference frames. In such cases, using known points to assess deviations from site conditions and ensure coordinate consistency leads to greater practical usability. The real objective is not just the accuracy of the positioning itself, but producing positional information that can be used on site.

Furthermore, using multiple known points makes it easier to detect problems that are difficult to see with single-point checks. If a point is correct in one location but offset in another, it may not be a simple translation but could involve rotation, scale, or localized environmental effects. Such anomalies cannot be overlooked when staking out the positions of critical structures or verifying as-built conditions.

Using control points and known points may seem to add extra work. However, it is far more efficient than having to go back and redo work later. The accuracy of RTK-GPS is not just about obtaining numbers; it only becomes meaningful when you can confirm those numbers are correct relative to the site reference. For that reason, verification of known points should not be skipped; it should instead be a central step in any high-precision operation.

Method 7 Standardize work procedures to reduce human error

When considering the accuracy of RTK-GPS, attention tends to focus on satellites, communications, and device performance, but at the site human factors also account for a very large portion of errors. That is why, even with the same equipment and the same site, results can differ when the operator changes. To achieve stable high-precision positioning, it is important to standardize work procedures rather than rely too much on individual experience and intuition.

There are many situations in which human error arises. When differences—people measuring antenna height differently, vague criteria for confirming fixed solutions, inconsistent observation durations, some people checking known points while others do not, and unstandardized methods of recording data—accumulate, the overall accuracy becomes unstable. Moreover, these issues often appear as equipment problems, which makes them troublesome because improvements tend to be delayed.

What is needed, then, is the development of procedures and checklists that bring the quality close to the same regardless of who performs the work. For example, explicitly documenting what to check before starting observations, the waiting time to confirm a fixed solution, the method for measuring antenna height, the conditions that require re-observation, the frequency of checking known points, and procedures for responding to anomalies will reduce variation in judgment. Even if something is obvious to experienced personnel, it will not be shared unless it is documented.

Standardizing records is also important. If it is not recorded which point was observed, when, and under what conditions, you cannot trace the cause of errors afterward. Conversely, if you record the observation time, the state of the solution, verification results, and whether re-observation was performed according to a consistent set of rules, it becomes easier to narrow down the cause when a problem occurs. From a quality management perspective, recording is as important as measuring.

Standardization is also effective in education. While RTK-GPS is convenient, it has the pitfall that users tend to take the displayed values at face value. Therefore, it is important to share the background—why confirming a fixed solution is necessary, why checks with known points are needed, and why re-observations are carried out. If people understand the purpose of the procedures, they will be better able to make appropriate judgments when they encounter unexpected situations in the field.

Ultimately, an organization that stabilizes the accuracy of RTK-GPS does not leave equipment operation to individual discretion. The same checks are performed regardless of who uses it, acceptability is judged by the same criteria, and records are kept to the same standard. If this state can be achieved, positioning errors can be greatly reduced. Improving accuracy is not only about increasing the capability of the machine but also about raising the quality of on-site operations.

Operational considerations for improving RTK-GPS accuracy

So far we have introduced seven methods, but the more important thing is not to treat each one as a standalone countermeasure and instead to connect them into a continuous operation. Improving RTK-GPS accuracy is not something that will be dramatically accomplished by a single trick. Stable high accuracy is obtained only as the result of accumulating elements such as reception environment, installation, corrections, solution verification, re-observation, comparison with known points, and standardization of procedures.

On site, a common reaction to poor accuracy is to dismiss it with vague phrases like "the satellite conditions are bad today" or "the equipment isn't in great shape." However, if you truly want to improve accuracy, you need to break down and analyze what caused it. Was there a problem with how open the sky was, was the setup unstable, did the correction information get interrupted, was the fixed-solution confirmation lax, was re-observation insufficient, or had you not checked with known points? Once you can make these distinctions, the rate of improvement at each site will rise dramatically.

It is also important to organize accuracy targets on a per-task basis. There is no need to demand the same level of strictness for every operation. The level of control required differs between situations where a rough understanding of position is sufficient and those where even slight deviations are unacceptable. For this reason, an approach that spends time on critical points while prioritizing efficiency for routine matters is effective. Improving accuracy also means applying the necessary effort where it is needed.

Furthermore, field operations that aim to increase accuracy do not respond after problems occur; they establish workflows that make problems less likely. They check the observation environment before work, verify consistency at known points, wait for a stable fixed solution, re-observe at key locations, and keep records. Once this workflow is established, positioning errors become a manageable risk rather than an incidental problem.

RTK-GPS is a technology that can greatly increase on-site productivity when used correctly. However, to maximize its effectiveness, simply bringing the equipment to the site is not enough. Standardizing on-site operations to ensure accuracy will ultimately make the biggest difference.

Summary

To improve RTK-GPS accuracy, you must not treat positioning errors as mere chance; instead, adopt an approach of eliminating each cause one by one. Choose an observation environment with an open sky, install the antenna correctly, receive correction information stably, carefully verify fixed solutions, increase measurement reliability through re-observation, reconcile measurements with known points, and standardize work procedures. Simply enforcing these seven practices can significantly improve positioning quality in the field.

RTK-GPS is a high-precision technology, but accuracy is not automatically guaranteed. That is why it is important to establish highly reproducible procedures in daily operations and put in place a system that ensures consistent results regardless of who performs the work. What truly matters to practitioners is not theoretically high precision, but the stability of accuracy that can be relied on in the field.

If you want to carry out this kind of accuracy management in a way that better fits the field, it can be effective to adopt measures that offer mobility and ease of use. For example, using an iPhone-mounted GNSS high-precision positioning device like LRTK makes it easier to incorporate high-precision positioning into daily workflows and can improve the immediacy of position checks and record-keeping. If you want to realize RTK-GPS accuracy in the field rather than letting it remain a desk-based performance metric, reviewing your setup to include such operationally friendly mechanisms can help you achieve a balance between accuracy and work efficiency.