Table of contents

• Reproducibility: confidence that repeated measurements yield the same result

• Stable field operation: being able to keep measuring without interruption

• Data consistency: the key to survey results without contradictions

• Simple surveying with LRTK

When people think of RTK positioning, the first thing many imagine is "positioning accuracy." RTK (Real Time Kinematic) is a technology that uses GNSS (Global Navigation Satellite Systems) to correct position errors in real time, enabling high accuracy down to the centimeter level (half-inch accuracy). In the surveying industry, RTK-GNSS surveys with dedicated equipment have dramatically improved productivity and reduced labor, and recently RTK positioning using smartphones has attracted attention as well. Therefore, when considering the introduction of RTK, interest tends to focus on "how high the accuracy can be."

However, deploying positioning technology in real field work requires things that are even more important than accuracy. These are reproducibility (obtaining the same result whenever you measure), stable field operation (positioning that does not drop out or become unstable), and data consistency (survey data that are free of contradictions and consistent). No matter how good the numbers on a catalog look, they are meaningless if results vary or the system is unusable on site. This article explains the importance of reproducibility, stable operation, and data consistency as aspects of RTK surveying that matter more than simple accuracy.

Reproducibility: confidence that repeated measurements yield the same result

In precision surveying, reproducibility—whether you get the same result each time you measure the same point—is critically important. For example, experienced surveyors habitually re-measure important points at different times or verify them with a different method. That is because even when instruments report high-accuracy positions, rare incorrect values can arise from environmental factors or setup mistakes. High reproducibility greatly increases confidence in measurement results. Conversely, if reproducibility is low—that is, results vary each time you measure—you cannot tell which result is correct, and even a high-performance instrument will lose credibility on site.

RTK positioning can theoretically achieve centimeter-level accuracy (half-inch accuracy), but that accuracy is not guaranteed at all times. Factors that affect reproducibility include time-varying error sources such as satellite geometry and the state of the ionosphere and troposphere. For example, measuring the same point in the morning and afternoon can yield differences on the order of several centimeters (several in) because of differences in satellite geometry. However, with a system that has high reproducibility, such differences remain within acceptable bounds and the surveyor can rely on the results. In a system with low reproducibility, these error variations can be large, leading to situations where "the point measured yesterday does not match today's measurements."

Ensuring reproducibility requires thoughtful measurement procedures in the field. In RTK surveying, if possible it is desirable to observe the same point multiple times at different times and confirm that the results are stable. Regularly observing control points (known points) to verify that the equipment and correction data have not drifted is also effective. If large discrepancies appear between different observations, actions such as restarting equipment, checking environmental factors, or re-measuring with another method (for example, a total station) may be necessary. Only when stable reproducibility is achieved can the high accuracy of RTK truly be put to use.

Stable field operation: being able to keep measuring without interruption

No matter how high the accuracy, it is wasted if the system cannot be operated stably in the field. Stable field operation means being able to continue positioning smoothly without interrupting survey work. RTK surveying can suffer interruptions due to communications or environmental influences. For example, an RTK-GNSS receiver provides centimeter-level accuracy while it maintains a fixed solution (Fix), but in places where satellite signals are obstructed—such as among tall buildings or in forests—the fixed solution may be lost and the receiver can revert to a degraded floating solution (Float) with lower accuracy. Once a fixed solution is lost, it can take time to regain a stable solution, forcing work to stop in the meantime. Such situations greatly reduce field efficiency and affect work schedules.

Achieving stable field operation requires both technical measures and operational practices. On the technical side, it is important that receivers support multi-GNSS (multiple satellite systems) and multi-band (multiple frequency bands). Receivers that can pick up signals from many satellites are more likely to maintain the number of satellites needed to keep a fixed solution in urban canyons or under tree cover. In Japan, using the QZSS (Michibiki) centimeter-class augmentation service (CLAS) is also effective. For example, in mountainous areas without cellular coverage, receiving correction information directly from Michibiki satellites allows high-accuracy positioning to continue without relying on the Internet. By combining multiple methods like these, you can reduce the number of situations in which "no radio signal means you can't measure."

On the operational side, simplifying equipment as much as possible to reduce potential trouble sources is key. Traditional RTK surveying often required setting up your own base station and broadcasting corrections via radio, and setup mistakes or communication failures were common causes of instability. Recently, network RTK using internet-distributed correction services (Ntrip) and the aforementioned CLAS have reduced the need to set up base stations. For long workdays in the field, battery life and dust/water resistance of equipment are also important. Having spare batteries and choosing rugged receivers that operate reliably in rain enable stable operation regardless of weather or working hours.

Ease of operation is also directly linked to stability. If device connections are complicated or there are too many settings, mistakes and trouble are more likely on site. A simple system configuration and automated workflows that make the device easy for anyone to handle are ideal. Because field teams must accomplish many tasks in limited time, it is important to create an environment where they can focus on surveying rather than "taking care of the machine." With a stable RTK system and intuitive operation, surveyors can carry out positioning work on site with confidence.

Data consistency: the key to survey results without contradictions

Survey data are important not only for point accuracy but also for being mutually consistent and free of contradictions—this is data consistency. For example, if you integrate point cloud data measured one day with data measured the next day and the coordinate systems are offset, discrepancies will appear on maps and drawings. No matter how accurate each individual survey is, inconsistent data dooms the final deliverable to problems.

A key to ensuring data consistency in RTK surveying is to consistently use a common reference. Concretely, this means unifying control point coordinates and geodetic datums, using the same reference when surveying on different days, and having multiple surveyors verify against common known points before and after surveying. For instance, processing data with a mix of a locally defined coordinate system and a public coordinate system (such as a global geodetic datum) can lead to large offsets later. When installing a base station, you must correctly set and record its installation position (coordinates) each time and manage it so the same reference is used across days. Even small mismatches in reference lead to inconsistencies when comparing coordinate data, negating the value of high accuracy.

Various practices are used in the field to prevent such inconsistencies. One example is establishing control points for each site and performing verification measurements—measuring those control points at the start and end of each workday to confirm data consistency. If references have drifted during the work, it is possible to perform post hoc corrections to adjust the data, but this is time-consuming. Acquiring data with consistency from the outset leads to more efficient and reliable surveying.

Data consistency can also be strengthened by using IT technologies. Recently, cloud-based data management platforms make it possible to integrate and share survey data collected by multiple workers in real time. Uploading coordinates, notes, and photos from the field to the cloud lets the entire team reference the same up-to-date data, making it easier to produce consistent deliverables. Tools that automate comparison with past survey histories and difference checks can detect missing data or mistakes early and allow corrections. Building a workflow that emphasizes data consistency reduces rework in drawing production and construction stages and helps ensure quality.

Simple surveying with LRTK

How can we make surveying itself easier while satisfying these "more important than accuracy" requirements? One answer is our smartphone-compatible RTK solution, LRTK. LRTK consists of a compact, high-precision GNSS receiver that can be attached to a smartphone and a dedicated app, realizing RTK positioning in a palm-sized device. By attaching the dedicated receiver (LRTK terminal) to a smartphone and launching the app, users can start centimeter-level positioning (half-inch accuracy) without the complicated base station setup, which is a major convenience.

Using LRTK makes it easier to ensure reproducibility, stable operation, and data consistency. First, LRTK visualizes and records positioning results on the smartphone in real time, so you can immediately confirm whether repeated measurements of the same point are stable. In practice, repeated measurements of the same point have consistently fallen within several centimeters (several in). Using a function that averages measurements over a set period can even improve accuracy down to the millimeter (0.04 in) level. This makes verification of important points straightforward and enables the collection of highly reproducible data.

Second, LRTK offers excellent stability. The receiver supports not only GPS but also GLONASS, Galileo, and QZSS (Michibiki), allowing it to track many satellites and provide stable positioning in urban and mountainous areas. Some models also support the aforementioned CLAS augmentation signal, maintaining high accuracy from satellite-provided corrections even in areas without cellular reception. LRTK can also connect to network RTK services (Ntrip, etc.), obtaining correction data from regional electronic reference networks where available to secure accuracy. By flexibly switching between communication infrastructure and satellite augmentation depending on conditions, LRTK supports stable operation so positioning does not drop out at any site.

Third, LRTK provides strong mechanisms for data consistency. The smartphone app integrates with the cloud so that coordinates, photos, and notes collected during positioning are saved and shared in the cloud. This allows all team members to reference the same latest data, reducing the chance of inconsistencies when multiple people survey. Because all survey points are recorded in the same reference system (for example, a global geodetic datum) and centrally managed in the cloud, later data reconciliation does not produce mismatches. Field data can be shared instantly with the office and other teams, helping prevent confirmation errors and omissions.

Additionally, LRTK is designed to be easy for anyone to use. It minimizes the specialized settings typical of conventional RTK equipment; surveying proceeds by following on-screen guidance in the app. There is no need to set up a base station yourself—just a smartphone and the LRTK terminal are enough to begin work immediately on site. This enables teams without dedicated surveying staff to perform the necessary positioning tasks. Even for experienced surveyors, reduced time spent on equipment preparation and postprocessing means more time for core decision-making. As labor shortages worsen, LRTK—allowing anyone to perform accurate, reproducible surveying—is becoming a new standard for "simple surveying" that improves field productivity. Combining accuracy, reproducibility, stability, and consistency in an easy-to-use package, LRTK has the potential to transform field surveying styles. When considering RTK equipment, look beyond catalog accuracy and consider reproducibility and operational reliability to make sure the stated accuracy can actually be realized—next-generation simple surveying solutions like LRTK are worth considering.

FAQ

Q1. What degree of accuracy can RTK surveying achieve? A. In general, RTK-GNSS surveying can achieve horizontal accuracy on the order of several centimeters (several in) and vertical errors on the order of several centimeters to a dozen or so centimeters (several in to more than 4 in) under favorable conditions. RTK using smartphones can achieve accuracy comparable to dedicated equipment if base stations and correction information are used properly. In fact, LRTK standalone positioning generally falls within about 1–2 cm (0.4–0.8 in) of error, and averaging data over a period can yield sub-1 cm (< 0.4 in) accuracy. However, accuracy varies with satellite geometry and signal conditions, so for important measurements it is safe to proceed only after confirming a stable fixed solution (Fix).

Q2. Is RTK surveying possible in urban canyons or forests? A. In urban canyon environments surrounded by tall buildings or in dense forests, satellite signal reception can be poor, making it difficult to maintain RTK accuracy and keep a fixed solution. Signal blockage and multipath reflections can make positions unstable, increasing errors or causing a fix to revert to a float solution. Still, using a multi-GNSS, multi-band receiver to increase the number of available satellites can mitigate accuracy degradation to some extent. Another approach is to move briefly to an open area to obtain an initial fix and then continue work using the phone’s inertial sensors or AR markers to supplement position. However, where satellites cannot be received at all—such as inside tunnels or buildings—RTK is not applicable; alternatives include short-range radio-based local reference points and distance measurements between mobile units, IMU-based dead reckoning, and SLAM (vision-based positioning) techniques. In short, in environments where satellite positioning is difficult, it is important to be flexible and switch to conventional methods such as total stations as appropriate.

Q3. Does LRTK support QZSS Michibiki CLAS? A. Yes, LRTK has receiver models that support CLAS (centimeter-level augmentation service). CLAS-compatible models can receive augmentation signals directly from the Michibiki satellites, enabling centimeter-level positioning (half-inch accuracy) even at sites where the Geospatial Information Authority of Japan’s electronic reference network or Ntrip Internet connections are not available. This is very reassuring because it allows high-precision positioning in mountainous areas without cellular coverage or offshore locations, provided the sky is open. Note, however, that CLAS service coverage is basically limited to Japan.

Q4. How will on-site work change if we introduce LRTK? A. Before introducing LRTK, surveying and as-built control were often handled by specialist survey staff or outsourced, and construction proceeded after waiting for survey reports. On-site verification between planned drawings and the real site often relied partly on human inspection and experience, with the risk of rework and errors. With LRTK, field staff can perform staking and measurements themselves and immediately verify and share results via AR displays. Real-time construction management speeds up decision-making and enables early detection and correction of errors. Tasks that used to require two to three people can often be completed by one person, increasing flexibility in staffing. Many users report a significant reduction in waiting times and rework and an overall improvement in field efficiency.

Q5. Can people with limited surveying experience use LRTK? A. Yes. LRTK is designed with ease of use in mind, and the dedicated smartphone app offers intuitive operation. Positioning starts with a single tap, and correction reception and calculations are handled automatically, so complex settings are not required. That said, understanding basic surveying concepts such as latitude/longitude and datums helps in handling results correctly. By introducing LRTK, people without deep surveying expertise can still perform location measurements and as-built checks with a useful degree of accuracy, expanding the scope of on-site work.