Can you do drone surveying with RTK? 5 things to check before implementation

Among practitioners interested in surveying using RTK, many may want to know whether RTK can be applied not only to ground-based positioning but also to drone surveying. In short, RTK can be used for drone surveying. However, if you decide to adopt RTK based solely on the term "RTK," you may not achieve the accuracy or efficiency you expect. This is because the accuracy of drone surveys is determined not only by the aircraft's positional accuracy but also by the imaging method, the approach to calibration and referencing, site conditions, the types of deliverables, and the operational setup.

In particular, if you are considering adoption for purposes such as quickly grasping a wide area from the air, streamlining earthwork volume checks, or increasing the frequency of site condition assessments, it is risky to decide solely on whether a unit is equipped with RTK. While RTK is certainly useful in many situations, it is not a panacea. Approaching it with the same mindset as single-point ground observations can lead to differences in the reliability and reproducibility of survey results.

This article begins with the basics of whether drone surveying is possible with RTK, and organizes five practical points to check before adoption. By carefully reviewing accuracy considerations, the need for calibration, site conditions, compatibility with required deliverables, and the operational workflow, you can more easily avoid failures after implementation. Rather than being swayed by the term RTK, please read through to the end as a way to determine whether it truly fits your company's operations.

Table of Contents

• Can drone surveying be done with RTK?

• Confirmation item 1: What deliverable is being requested?

• Confirmation item 2: Can RTK alone meet the required accuracy?

• Checklist item 3: Is the site environment suitable for RTK flight?

• Check Item 4: Can the entire workflow be made more efficient?

• Confirmation item 5: How should the division of roles with ground surveying be considered?

• Summary

Is drone surveying possible with RTK?

Drone surveying with RTK is fully feasible. In fact, in recent years it has become common to efficiently acquire georeferenced images and point clouds from the air and use them for terrain mapping, as-built verification, current-condition recording, and earthwork volume management. In that context, RTK is used as an important mechanism to support improved accuracy of image capture positions and aircraft positions.

However, what should be clarified here first is that using RTK is not the same as survey results automatically becoming high-precision. RTK is a technology that uses correction information for satellite positioning to improve positional accuracy, but in drone surveying you need to understand where that positional information is reflected in image capture and point cloud acquisition, and at which stages errors can be introduced. Even if the aircraft position can be obtained with high accuracy, if shooting conditions are poor the analysis results will be distorted, and if ground control is ambiguous it will be difficult to ensure consistency of the deliverables.

In practice, reasons for adopting RTK-equipped drone surveying include expectations to reduce ground control work, to measure wide areas in a short time, and to lessen the burden of repeated observations. These are indeed realistic benefits. On large development sites, earthwork sites, slopes, and temporary soil stockpile management, it is faster and makes it easier to track changes to capture area-wide information from the air than to pick up points one by one from the ground.

On the other hand, for boundary-related matters where accuracy requirements are strict, in environments with heavy occlusion, or at sites with many areas that cannot be seen from aerial photography alone, it can be difficult to complete everything using only RTK drones. In other words, the precise answer to the question of whether drone surveying can be done with RTK is that it is technically possible, but a design tailored to the project objectives and required accuracy is indispensable.

The important thing is not to make the introduction of RTK an end in itself. What is truly needed on site is to continuously obtain reliable, work-ready results through manageable operations. For that reason, it's important to systematically organize, in order, what should be checked before introduction.

Confirmation Item 1: What is being requested as the deliverable?

The first thing I want to confirm is what you ultimately want to produce with RTK drone surveying. If this remains unclear when you move forward with implementation, decisions such as selecting the drone, flight methods, supplementary ground surveys, and how to set analysis parameters will all become inconsistent.

For example, whether you only want to quickly visualize the current conditions, understand surface undulations, compare earth volumes, or verify as-built conditions and reconcile them with the design will greatly change the required accuracy and operational methods. If you only want to share overall progress based on aerial photographs, a certain amount of error may be acceptable in practice. However, when used for quantity calculation or elevation management, strong stability is required not only horizontally but also vertically.

What needs to be noted here is that the term "drone surveying" is too broad. Whether you are creating a stitched planar image from photographs, reproducing three-dimensional shapes, treating the data as a point cloud, or using it for cross-section generation and earthwork volume calculations, the required preconditions differ. The value of using RTK is not simply that it provides positional information, but how much that positional information contributes to the overall consistency of the deliverable and its tie to ground reference.

What the person responsible for implementation should do first is to clarify the intended uses of the deliverables within the company. Simply by organizing who will use them, what decisions they will inform, how frequently measurements will be taken, and what degree of error is acceptable, the outline of the required operations becomes considerably clearer. For example, if it is a regular monitoring to observe weekly changes in soil volume, it is important that measurements can be easily repeated under the same conditions, and if it will be used as explanatory material for the client or other stakeholders, visual clarity and data consistency are also important.

Conversely, if you implement it without deciding the intended use of the deliverables, you may end up chasing unnecessarily high accuracy and just increasing workload, or conversely fail to meet the required accuracy and need to re-measure. RTK drone surveying is convenient, but it is not suited to the idea of doing everything with a single drone. The first thing to confirm is what you will produce and what decisions those deliverables will be used for.

Confirmation 2: Can RTK alone meet the required accuracy?

The next important point is to verify whether RTK alone can meet the required accuracy. This is the part where the most misunderstandings occur during deployment. The term RTK conveys an impression of high precision, but the accuracy of drone surveying is not determined solely by the drone's position correction.

In aerial surveying, the final products are produced by the accumulation of various factors such as the flight altitude at the time of capture, overlap rate, camera orientation, shutter timing, the shape of the target, how the ground surface appears, and processing conditions during analysis. Even if RTK is highly accurate, analysis results can become unstable in areas where the ground surface is monotonous and feature points are scarce, in places with many reflections, or where vegetation covers the surface. In addition, vertical measurements tend to be more sensitive to errors than horizontal ones, so special care is required when using them for volume calculations or cross-section evaluations.

Therefore, in practice, even when using RTK, it is essential to adopt the approach of establishing ground control points and check points as needed to verify the validity of the deliverables. It is often assumed that an RTK-equipped aircraft can completely eliminate control points, but in reality the presence or absence of ground checks should be determined based on the importance of the task and the required accuracy. Especially at a site being operated for the first time, rather than taking RTK results at face value, it is safer to compare them with points checked on the ground to understand the error trends.

It's also important not to leave the definition of required accuracy ambiguous. The required level varies depending on whether it's sufficient for only the planar position to match, whether heights need to be consistently accurate, whether knowing relative differences is enough, or whether the data must be alignable with other survey results as absolute coordinates. Even with the same RTK drone surveying, priorities differ between progress monitoring and as-built control. Confusing these can make unforeseen discrepancies problematic after implementation.

Furthermore, when survey results are to be used continuously, attention should be paid not only to single-measurement accuracy but also to reproducibility. If it was correct today but off next time, or the results change when the person in charge changes, the operation will not be stable. It is necessary to consider accuracy management, including RTK correction reception status, reproducibility of flight plans, methods of ground verification, and standardization of analysis conditions.

In other words, RTK is a promising approach, but by itself it does not guarantee the required accuracy. Before deployment, it is essential to clarify how much accuracy is needed for the intended tasks and to determine whether RTK alone is sufficient or should be combined with ground verification.

Check Item 3: Is the site environment compatible with RTK flights?

The third item to check is whether the site environment is compatible with RTK flights. No matter how good the equipment or operating procedures are, if site conditions are poor it will be difficult to achieve consistent results. While RTK drone surveying can efficiently collect information from the air, it is affected by both satellite reception and aerial imaging conditions.

The first thing to be aware of is the degree of openness overhead. At sites where there are many tall structures, obstacles at the top of slopes, trees, or overhead wires, satellite-signal reception tends to become unstable. Because RTK performs high-precision positioning while receiving correction information, unstable satellite reception can cause the RTK solution to fluctuate. The same is true for ground-based RTK operations, but with drones the situation can change during flight, so verifying stability is even more important.

Additionally, the communication environment cannot be ignored. Depending on the method used to receive correction data, poor on-site communications can make positioning unstable. In mountainous areas, large-scale sites in the early stages of development, or locations with weak communications infrastructure, flights may be possible but correction operations can be constrained. Before deployment, you should prepare pre-check procedures to determine how stably corrections can be handled in the target area.

Furthermore, the condition of the subject being photographed is also a major factor. In areas with dense vegetation it becomes difficult to correctly capture the ground surface, and water surfaces, highly reflective surfaces, or monotonous terrain present conditions unfavorable to image analysis. Even if you want to capture the undulations of the soil or the shape of slopes, depending on surface conditions you may not achieve the expected density or shape reproduction. Regardless of whether RTK is available, you should understand that some sites are suited to aerial imaging while others are better suited to ground surveying.

From a safety perspective, it is also necessary to verify compatibility with the site. Factors such as how easily flight routes can be secured, whether there is space for takeoff and landing, whether it will interfere with the movement of people and vehicles, and whether flights can be conducted under the same conditions during regular surveys directly affect not only survey quality but daily operations as well. If special adjustments are required for each site, the benefits of implementation are likely to diminish.

In practice, decisions to introduce RTK drone surveying are sometimes made without seeing the site environment, and teams can encounter issues such as it being harder to fly than expected, position corrections being unstable, data processing taking longer, and the ground surface being difficult to see. To succeed with RTK drone surveying, it's important not only to look at the equipment specifications but also to confirm whether the target site is truly suitable for that operation. Before implementation, envision representative sites and, at a minimum, check four items — aerial visibility, communication conditions, how the targets appear, and safe flight paths — to make judgment easier.

Checklist Item 4: Can the entire workflow be made more efficient?

The fourth thing to check is whether RTK drone surveying leads to efficiency gains across the entire workflow. It is important here not to judge that based solely on flight time. True, using drones makes it easier to capture wide areas quickly and comprehensively. However, unless you take into account planning, pre-flight preparation, site inspections, installation of ground control points, data organization, analysis, and verification of results, the real efficiency will not be apparent.

When considering implementation, there is often a tendency to expect that work that used to take a full day on the ground can be finished quickly from the air. However, if the post-capture processing burden is large, the total man-hours may not be reduced that much. In particular, during the initial phase, trial-and-error with flight conditions, adjustments to analysis parameters, and verification of deliverables tend to take time; even if on-site time can be shortened, in-house work may increase.

Therefore, before implementation, it is necessary to break down and consider which processes you want to shorten. The optimal operation varies depending on whether you want to reduce measurements by pacing and quick inspections for understanding current conditions, increase the frequency of earthwork volume comparisons, or reduce rework from as-built verification. Drone RTK surveying is strong in situations where a wide area is repeatedly observed using the same method. Conversely, for tasks that involve detailed checks of a narrow area or for complex locations with many obstructions, ground surveying can be faster.

Also, the staffing structure is important. If it is unclear who is responsible for flight operations, positioning management, ground verification, analysis, and result verification, operations tend to become dependent on specific individuals after implementation. If only particular staff can handle the tasks, maintaining operations during busy periods or when personnel change becomes difficult. To establish RTK drone surveying, it is necessary not only to be able to fly the aircraft but also to organize processes so that the outputs are usable as deliverables.

Furthermore, the rate of rework cannot be overlooked. If re-flights or re-analyses occur because corrections were unstable, the imaging coverage was insufficient, or required ground checks were omitted, it will increase the burden rather than improve efficiency. Before implementation, design standard procedures and decide what should be checked on site and at what point quality judgments will be made; doing so makes it easier to reduce rework.

In other words, the value of RTK drone surveying is not just that flights are fast. The essence lies in whether, when viewed across the entire workflow from field work to deliverables submission, it can reduce man-hours, speed up decision-making, and stabilize the quality of records. Before implementation, it is important to check for opportunities to improve efficiency not only in on-site tasks but also in the preceding and subsequent processes.

Confirmation Item 5: How should we consider the division of roles with ground surveying?

The fifth item to consider is how to divide roles between aerial and ground surveying. A common mistake when introducing RTK drone surveying is trying to replace all of the existing ground surveying. In reality, however, aerial surveying and ground surveying have different areas of strength. Clarifying the roles of both and combining them is more practical in terms of accuracy, efficiency, and repeatability.

Drone surveying excels at capturing large areas as surface data in a short time. It is highly effective for overall assessment of current conditions, checking changes in terrain, grasping trends in earthwork volumes, and comparing progress. On the other hand, it struggles with areas such as the backs of structures, under eaves, beneath trees, confined spaces, and locations not visible from the air. Also, for managing important control points and for sites that require precise verification, the reliability of ground surveying is indispensable.

If you try to complete everything with drones alone without understanding this difference, gaps in unseen areas and judgment errors due to insufficient checks are likely to occur. Conversely, if you do everything on the ground as before, the effectiveness of introducing drones will be limited. The important thing is to clearly define what to capture from the air and what to handle on the ground.

For example, using drones to capture the overall terrain and temporary stockpiles while confirming important control points and reference locations on the ground is an operational approach that fits well with practical work. Employing drones for regular wide-area monitoring and using ground RTK or other ground surveys for accuracy checks and localized detailed inspections makes it easier to balance efficiency and reliability.

Also, for easier internal communication, clarifying the division of roles is important. While data collected by drones is visually appealing and easy to share, if it is unclear to what extent it can be used as a basis for decision-making, differences in understanding can arise between field personnel and management. Establishing rules in advance—such as “verify this with drone results” and “prioritize on-site verification for this”—will stabilize operations.

Moreover, thinking about the division of roles also contributes to education. If the person responsible for RTK drone surveying understands not only aerial photography but also the basics of ground surveying, they can reduce misinterpretation of results. Conversely, if the person responsible for ground surveying understands the characteristics of drone-derived results, it becomes easier to appropriately incorporate necessary supplementary observations. Designing operations based on the strengths of both, rather than leaning toward one side, is the quickest route to successful implementation.

Summary

Drone surveying with RTK is possible, and in practice it can be a powerful tool when you need to efficiently grasp large areas. However, judging the value of adopting it based solely on the term “RTK” can easily lead to a gap between expectations and reality. What is important is to clarify what deliverables you require, determine whether RTK alone can meet the necessary accuracy, check compatibility with the field environment, consider whether you can streamline the entire workflow, and finally organize the division of roles with ground surveying.

If you check these five points in advance, you will be better able to avoid common post-deployment problems such as lower-than-expected accuracy, frequent rework, reliance on a single operator, and inconsistent results across sites. RTK drone surveying should not be determined solely by the aircraft's performance; it should be considered a comprehensive system that includes objectives, the site, precision management, and operational design.

Especially for practitioners who are searching for information using RTK, how to link aerial surveying with high-precision ground positioning will become increasingly important. If you can use drones for wide-area reconnaissance and high-precision ground positioning for spot checks and on-site work, it becomes easier to balance the speed and accuracy of decision-making across the whole site.

In that sense, when considering the introduction of drone surveying, it is practical to think not only in terms of completing measurements from the air but also to include ground-side RTK operations. For example, if you want to quickly confirm points, carry out supplementary observations, or perform re-checks on site, combining an iPhone-mounted high-precision GNSS positioning device like LRTK makes it easier to divide roles between the air and the ground. If you can establish a workflow in which the drone captures the overall picture and the ground immediately secures required spots with high precision, you can further enhance the efficiency and user-friendliness of surveying operations.