Key Factors for Solo Surveying: Communication and Accuracy — Why LRTK's RTK/GNSS Is Chosen

The concept of “solo surveying,” where field surveying tasks can be completed by a single person, is attracting attention. Tasks that used to require a team of a surveyor and an assistant—such as stakeout and as-built verification—are increasingly feasible for one person thanks to advances in GNSS technology and data communication infrastructure. However, two critical factors are required to make solo surveying successful: “communication” and “accuracy.” This article explains why communication environments and positioning accuracy are decisive for solo surveying, and highlights the reasons LRTK’s RTK/GNSS is being chosen in the field as a solution that satisfies both.

Challenges at Survey Sites and the Need for Solo Surveying

Traditional surveying work has relied on advanced specialized skills and multiple personnel. With conventional methods using tape measures, staffs (level rods), levels, and transits—measuring points relative to reference points—working in teams of two to three people was the norm. For example, one person would operate the instrument on a tripod while another held the staff at a distant point to lay out positions. This manual, labor-intensive approach required significant setup and takedown time, and if there were many measurement points or a wide site, surveying alone could easily consume an entire day.

Manual measurements also carry the risk of human error. Misreading numbers or recording mistakes can cause rework in later stages, leading to schedule delays and increased costs. With limited time and personnel, it’s often difficult to measure every point, so teams typically measured only the most critical locations. That approach carries the risk that issues at unmeasured locations go unnoticed.

Meanwhile, the construction industry has been facing increasingly serious problems with labor shortages and an aging workforce. With fewer experienced surveyors available, continuing to rely on people for surveying is becoming difficult, and there is growing demand for methods that allow small teams to perform high-accuracy surveys. GNSS-based solo surveying is seen as a promising solution. Solo surveying can significantly reduce labor at the site while still potentially providing the necessary accuracy. The next section looks at the evolution of GNSS and RTK technologies that hold the key to this capability.

How GNSS and RTK Technology Enable Solo Surveying

GNSS (Global Navigation Satellite System), which uses satellites to determine a user’s position, is familiar from car navigation and smartphone map apps. Numerous satellites—GPS (U.S.), GLONASS (Russia), Galileo (Europe), and Michibiki (Japan’s quasi-zenith satellite), among others—operate so that latitude, longitude, and altitude can be measured easily anywhere on Earth. GNSS holds great potential in surveying. Unlike traditional optical relative surveying (using transits or total stations to measure from reference points), GNSS surveying determines absolute positions directly with satellites as the reference, making it highly effective for understanding relationships between distant points and for surveying wide areas. Because GNSS can work as long as the sky is open—even in areas with limited line-of-sight such as mountainous regions—its application has expanded to sites that were previously difficult to survey.

However, standalone positioning with a typical GNSS receiver yields accuracy on the order of several meters. That level of error is unusable for construction surveying or boundary confirmation, tasks that require centimeter-level accuracy. For example, GPS signals in smartphones typically have errors of about 5–10 m, which is insufficient for stakeout or as-built verification. This is where RTK (Real Time Kinematic) comes in to correct GNSS positioning errors.

RTK works by having a known, accurately surveyed base station (reference point) and a rover (mobile receiver) simultaneously receive satellite signals. The base station computes error information and sends it to the rover via communication, and the rover applies the corrections to its own positioning. Because errors are compensated in real time, positioning errors that would otherwise be several meters can be reduced to a few centimeters. Historically, high-precision base station surveys required long static observations, but RTK made centimeter-level positioning available immediately, and since the 1990s RTK has spread through civil engineering and construction sites.

Traditionally, conducting RTK surveying required installing a dedicated base station near the site (within a few kilometers). That preparation and operation require expertise, and equipment has often been large and expensive, posing a barrier for small contractors or municipalities. In addition, the conventional style—where experienced operators carry heavy equipment to the site and operate base and rover with multiple people—meant that the high accuracy provided by RTK did not automatically translate into labor savings. To address this, there was demand for RTK solutions that were easier to use and allowed smaller crews. This led to the development of network RTK services that utilize resources such as the Geospatial Information Authority of Japan’s electronic reference point network. Methods like VRS (Virtual Reference Station) allow virtual reference stations to be configured near users and correction data to be distributed; by receiving correction data over the Internet, a single rover can achieve centimeter accuracy. Today, many high-precision GNSS correction services—including private-sector offerings—are available, making high-accuracy positioning possible without maintaining your own base station.

Thus, the evolution of GNSS and RTK technology has laid the foundation for solo surveying. The next section delves into one of the key elements that determines success for solo surveying: “communication.”

Communication Infrastructure Supporting Solo Surveying

In RTK, which performs high-accuracy positioning in real time, it is essential to transfer correction data from the base station to the rover. In other words, without a stable communication environment, the accuracy of solo surveying cannot be maintained. Traditionally, this meant configuring radio modems between the base and rover or connecting to correction services via the Internet. These setups required technical knowledge and time-consuming tasks such as installing relay stations and checking radio conditions.

Today, the barrier is much lower thanks to smartphones and mobile communications. By connecting to the Internet on site with a smartphone and accessing Ntrip-compatible correction services (network RTK services), you can receive correction data in real time without dedicated radio equipment. For example, accessing correction data from the Geospatial Information Authority of Japan’s electronic reference points—about 1,300 stations nationwide—via a smartphone gives an effect equivalent to having a nearby virtual reference station. As long as cellular coverage is available, a single rover can cover a wide field.

Even in areas without cellular coverage, such as remote mountains or immediately after a disaster, you don’t have to give up on solo surveying. Japan’s Michibiki transmits a free high-precision augmentation service (CLAS) that allows direct reception of correction signals from satellites even without Internet access. LRTK devices support CLAS, so in open-sky locations they can continue RTK positioning outside cellular coverage. This enables rapid situation recording by a single operator even at sites lacking communications infrastructure or in emergencies where traditional surveying would be difficult.

Communication also plays a crucial role in sharing survey data. Traditionally, field survey results were recorded on paper or USB drives and brought back to the office for PC upload and distribution. That process introduces time lags before stakeholders are informed, possibly causing delayed responses to issues found on site. Systems like LRTK that link smartphones and the cloud allow measured data to be uploaded on-site to the cloud and shared in real time with office staff. You can immediately cross-check coordinates measured in the field against design drawings or GIS maps, or report results to supervisors, preventing rework and speeding decision-making. In short, in solo surveying “communication” refers both to communication for exchanging correction information and to communication for sharing data—both of which are lifelines for maintaining efficiency and accuracy.

The High Accuracy Required for Solo Surveying

Another indispensable point when discussing solo surveying is positioning accuracy. Surveying aims to obtain accurate location information of terrain and structures or to place stakes and markers according to design. Position information with errors of several meters is impractical. Especially for tasks such as as-built management on construction sites or boundary confirmation, even a few centimeters of deviation can be unacceptable, so high-accuracy surveying is essential. Traditionally, optical instruments such as levels and total stations (electro-optical distance meters) were used and skilled technicians invested considerable effort to ensure accuracy. If solo surveying cannot achieve comparable accuracy, it cannot be entrusted with critical tasks.

Fortunately, as noted above, RTK can achieve centimeter-level positioning with GNSS. Using network RTK services, high accuracy can be maintained uniformly regardless of where on site you are. There is no concern about accuracy degrading with distance from a base station, and you can perform stable positioning while moving across large areas. This stable, high accuracy forms the basis that makes solo surveying feasible.

For example, using an LRTK device can yield horizontal accuracy on the order of ±1–2 cm and vertical accuracy of about ±3–4 cm. This is orders of magnitude better than typical smartphone GPS errors (5–10 m) and is comparable to traditional optical surveying instruments. In sites where LRTK has been adopted, tasks that used to require two people a full day have been completed by one person in a few hours after introducing LRTK. Because precise data can be collected quickly, you can measure all necessary points and avoid unforeseen problems caused by missed measurements.

The ability to obtain high-precision data in a short time also brings benefits for safety and quality control. Increased surveying efficiency reduces the time workers spend in the scorching heat, lowering heatstroke risk, and shortens exposure time in hazardous areas. Digitally and accurately measured data can be used directly in reports and drawings, eliminating transcription errors. A system that is easy for less experienced technicians to operate reduces mistakes and makes it easier to ensure surveying quality. In this way, RTK/GNSS technology that achieves high accuracy is a key element supporting the reliability of solo surveying.

Why LRTK’s RTK/GNSS Is Chosen for Solo Surveying

As described above, solo surveying requires simultaneously satisfying two requirements: a communication environment and high accuracy. LRTK, a very small GNSS receiver developed as a solution to achieve this easily, works in tandem with smartphones. LRTK is an innovative RTK-capable GNSS device that attaches to an iPhone; weighing about 165 g and roughly 1 cm thick, it houses an antenna for high-precision positioning and a battery in a smartphone-sized package. Mounted on the back of an iPhone and connected via Bluetooth or Lightning, your smartphone instantly becomes a high-precision GNSS surveying instrument. With surveying equipment that once weighed several kilograms now small enough to fit in a pocket, you no longer need to carry tripods around the site—one person can complete surveying and stakeout tasks with just a smartphone. LRTK is drawing attention as a solution that opens the era of “smartphone surveying.”

LRTK supports high-performance RTK methods and in Japan can utilize various correction sources such as the Geospatial Information Authority of Japan’s electronic reference point network via Ntrip and the Michibiki CLAS signal. In areas with mobile network coverage, correction data via VRS can be obtained instantly for real-time correction. In regions outside cellular coverage, CLAS augmentation signals from satellites can be received directly, maintaining centimeter-level accuracy. In other words, stable high-accuracy surveying by a single operator is possible nationwide, from urban areas to remote mountains.

LRTK is also chosen for its operational ease. When you arrive on site, simply attach the device to your iPhone, power it on, and launch the dedicated LRTK app (iOS). Initialization completes in a matter of tens of seconds and positioning reaches a fixed solution (Fix). Once Fix is obtained, high accuracy is maintained while moving, and if reception is briefly lost in places like tunnels, centimeter accuracy is restored within seconds. There’s no need to repeatedly set up a base station across a wide construction site, allowing a single operator to carry out continuous surveying. This leads to significant savings in personnel and time.

There are also data management advantages. LRTK supports cloud integration, enabling measured data to be shared from the field with a single tap. That eliminates the need to return with paper records and re-enter data. By the time you return to the office, results can already be shared among stakeholders, so if missing measurements or errors are found on site, you can report and receive instructions immediately. Photo-attached records and automatic report-generation features improve post-survey documentation workflows. With all data accumulated in the cloud, it’s easy to reference past survey results or centrally manage information from multiple sites, enabling DX (digital transformation) initiatives. Because you can use an existing smartphone, the cost of adopting LRTK is far lower than acquiring large surveying instruments. Some local governments that introduced LRTK were able to procure equipment inexpensively and perform rapid in-house surveying at disaster sites, shortening recovery lead times and cutting costs. These comprehensive benefits explain why LRTK’s RTK/GNSS system is being selected at many sites aiming to adopt solo surveying.

Easy Solo Surveying with LRTK

Finally, imagine how straightforward solo surveying can be with LRTK by walking through a typical workflow.

• Preparation: Upon arrival, firmly attach the LRTK device to your iPhone and power it on. Launch the dedicated LRTK app (iOS), connect to the device, and begin receiving GNSS satellites. After capturing satellites, RTK centimeter-level positioning becomes available in a matter of tens of seconds, and when the position reaches a fixed solution (Fix), you’re ready. No assistant is required—you can start surveying alone.

• Measurement: When you reach a point you want to measure, simply tap a button in the app to record the high-precision coordinates. For large sites, walk to each point and collect data. The LRTK and smartphone combination can automatically record many points and generate 3D point clouds, enabling detailed terrain surveys that used to require specialized equipment to be done by one person.

• Stakeout (Positioning): You can perform stakeout tasks alone and accurately place markers at design coordinates. By inputting the target coordinates into the LRTK app’s coordinate guidance function, the screen shows real-time direction and distance to the target. Following guidance like “move 5 cm to the east” or “10 cm to the north,” you can fine-tune the position and complete stakeout work that formerly required two people.

• Verification & Sharing: Measurement results can be checked on the smartphone screen in numbers and graphs, and vertical differences and distances are available in real time. Acquired data can be uploaded to the cloud with one tap, so by the time you return to the office the team already has access to the results. You can receive additional measurement instructions or immediately verify consistency with drawings, achieving a smooth, waste-free surveying workflow.

By leveraging LRTK, field surveying that once required multiple people becomes remarkably simple. Solo surveying using GNSS and smartphones dramatically improves efficiency, and immediate data sharing enhances construction management accuracy. By combining communication and accuracy, LRTK is becoming a new standard in the GNSS era. In an era of labor shortages, consider introducing LRTK-driven smart solo surveying at your sites.