No expertise required! High-precision surveying anyone can do with RTK devices

Table of Contents

• What is an RTK device?

• How RTK positioning works

• Accuracy and benefits achievable with RTK devices

• Differences from conventional surveying

• Why anyone can do it (simple operation and required preparations)

• Use cases for RTK devices

• Points to consider when choosing an RTK device

• Simple surveying with LRTK

• Frequently asked questions

What is an RTK device?

In recent years, demand for high-precision positioning on construction and civil engineering sites has risen rapidly. While the use of position information from car navigation systems and smartphone GPS has become more common, conventional GNSS (Global Navigation Satellite System) positioning typically suffers from errors on the order of several meters, which is insufficient for surveying or construction management that require millimeter-level accuracy. The devices attracting attention for this purpose are known as RTK devices.

RTK stands for “Real Time Kinematic,” and in Japanese it’s called “real-time kinematic positioning.” Simply put, it is a technique that uses multiple GNSS receivers to correct positioning errors in real time and determine positions with centimeter-level accuracy. An RTK device refers to surveying equipment that uses this RTK positioning technology to perform high-precision position measurements. What previously required specialized surveying equipment and experienced technicians is increasingly possible to perform easily on site using RTK devices.

How RTK positioning works

Let’s look at why RTK positioning can achieve such high accuracy. In standard GNSS positioning (standalone positioning), a single receiver receives signals from GPS satellites and computes its own position. However, this method is subject to errors from satellite orbit and clock inaccuracies, signal delays when passing through the atmosphere (ionosphere and troposphere effects), and signal reflections from terrain or buildings (multipath). Because standalone positioning cannot correct for these factors, errors of several meters are unavoidable.

By contrast, RTK positioning (relative positioning) uses two or more GNSS receivers simultaneously. Specifically, a base station (a receiver with a known position) is installed at a reference point, and a rover (a mobile receiver) measures positions while moving; both receive signals from the same satellites at the same time. Since the base station’s exact position is known, it can calculate the discrepancy (error) between the received signal and the expected measurement. That error information is sent to the rover in real time, and the rover applies the corrections to its own positioning result, producing a high-precision position with the errors removed.

A major feature of RTK is that simultaneous observations at two locations allow common error sources to be canceled out. The closer the base station and the rover are to each other, the more similar the satellite signal error sources they receive (satellite orbit/clock errors and atmospheric errors). Comparing the observation data from both stations cancels out these common errors and dramatically improves accuracy. RTK also uses the phase information of the carrier wave from the satellite. The carrier wavelength is relatively short—tens of centimeters—allowing high-resolution measurement of distance differences; by analyzing this phase difference, positions can be determined within a few centimeters (integer-cycle ambiguity must be resolved, but once a “fixed solution” is obtained, very stable high accuracy is achievable).

To perform RTK positioning, a communication method is required to send correction data from the base station to the rover. In many cases, data are exchanged in real time via dedicated radios (UHF transceivers) or the Internet (mobile communications). Recently, network RTK that provides corrections from networks of continuously operating reference stations run by national, municipal, or private operators—such as VRS—has become widespread. With an Internet connection, users can utilize RTK positioning without installing their own base station.

Accuracy and benefits achievable with RTK devices

Using RTK devices allows position measurements with an accuracy orders of magnitude better than conventional GPS positioning. While typical GNSS standalone positioning yields errors of about 3–10 m, RTK positioning can achieve horizontal accuracy within a few centimeters and vertical errors on the order of a few centimeters as well. Under favorable conditions, actual positioning can sometimes achieve about horizontal 2–3 cm (0.8–1.2 in), vertical 3–4 cm (1.2–1.6 in), effectively reducing multi-meter deviations to fingertip-sized errors. This high precision enables many tasks on site that were previously impossible to perform instantly.

For example, stakeout work on construction sites, which requires millimeter-level accuracy to place structures according to design drawings, can be performed accurately by a single person using an RTK device to mark measurement points. For wide-area topographic surveying, RTK can measure many points in a short time and obtain coordinates with centimeter accuracy. Tasks that formerly required several people and time-consuming measurements with total stations can be carried out more efficiently with RTK, leading to labor savings and shorter survey times.

The benefits of introducing RTK devices are not limited to accuracy. Because the obtained position information is recorded as electronic data, it can be directly imported into CAD drawings or GIS systems for use. This reduces handwritten recording errors and post-processing work, accelerating a digital surveying workflow. In addition, RTK provides results in real time, so measurement results can be checked on site and work can proceed accordingly. This helps prevent missed measurements and rework and is advantageous for quality control. In short, RTK devices bring major benefits to the field in terms of high accuracy, efficiency, and digital integration.

Differences from conventional surveying

Conventional surveying has been dominated by optical surveying using instruments such as total stations and levels. These instruments can achieve high accuracy, but require specialized operations like tripod setup, instrument leveling, backsighting, and sighting, and measurements typically required two or more personnel (a surveyor and an assistant). The measurable range is limited to areas with line of sight from the instrument, so covering a large site requires repeatedly relocating the equipment.

RTK devices, on the other hand, use satellite signals and can perform positioning over a wide area as long as line-of-sight to the sky is not obstructed. Once GNSS reception conditions are available, you can measure points while moving without setting reflectors on ground targets. Moreover, because RTK provides absolute coordinates in real time, the need to set up reference points (known points) on site beforehand or to perform post-measurement calculations is greatly reduced.

RTK also lowers personnel and technical barriers. RTK devices are portable and can be operated by a single person; they are designed to be usable even by non-specialist personnel. Recent products feature intuitive user interfaces and automatic correction functions, so basic operational procedures are enough for anyone to perform high-precision positioning. While conventional surveying was a skill limited to specialists, the advent of RTK devices has made surveying more accessible and easier to handle.

Why anyone can do it (simple operation and required preparations)

The reason people say “Anyone can use RTK devices without specialist knowledge” lies in the devices’ simplicity of operation and low barriers to adoption. Many commercially available RTK-compatible GNSS receivers can be used in conjunction with smartphones or tablets; positioning can be started simply by following the prompts in a dedicated app. Tap the “measure” button at the desired point and high-precision coordinates are obtained on the spot—just enter a point name or notes and save. The operation screens are designed to be easy to understand, allowing intuitive use without specialized surveying knowledge.

Prerequisites for using RTK positioning have also been greatly simplified compared with the past. For example, in Japan you can use reference-station data from the Geospatial Information Authority of Japan or private GNSS correction services, so you don’t have to set up your own base station. If you configure the RTK device once to use an Internet-based correction service (such as an NTRIP client), the device will automatically obtain correction information when started on site and begin high-precision positioning. There are also models that support the Quasi-Zenith Satellite System (QZSS) centimer-level augmentation service (CLAS), allowing devices to receive correction signals directly from satellites in areas without mobile coverage. CLAS-compatible RTK devices can maintain centimeter-level positioning even without terrestrial communications.

Advances in devices and services have made it easier to prepare the environment needed for RTK positioning, which is another reason why “anyone can use it.” In extreme cases, site staff without surveying qualifications can perform necessary measurements by following the manual. However, to make proper use of high-precision positioning results, it is reassuring to have basic knowledge such as understanding what the obtained coordinates mean and how to assess the quality of the positioning environment.

Use cases for RTK devices

Here are some examples of actual sites where RTK devices are useful.

• Civil and land surveying: RTK devices are powerful tools for topographic surveys of roads and land development sites. They can measure numerous terrain points across wide areas in a short time and reflect centimeter-accuracy data in maps and drawings. Compared with surveying using total stations, work time can be greatly reduced and personnel requirements minimized.

• Construction management and stakeout (layout): RTK is used for layout work of reference lines and structures on construction sites. Based on design coordinates, RTK can accurately position points on site so that even without experienced surveyors, a single person can mark points with millimeter accuracy. This not only improves construction accuracy but also helps alleviate labor shortages.

• Infrastructure inspection and maintenance: High-precision position measurement is useful for routine inspection of roads, railways, bridges, and other infrastructure. For example, monitoring pier displacement or road subsidence can be done by continuously observing the same point with RTK and detecting changes over time at the centimeter level. Precise coordinates measured in advance also make it quicker to locate repair sites, improving the efficiency of inspection and maintenance work.

• UAV surveying (drone photogrammetry): RTK technology is also applied to drone-based photogrammetry. RTK-capable drones can record the position of each aerial photo with centimeter-level accuracy, significantly reducing the number of ground control points (targets) required. As a result, high-precision 3D survey models (point clouds and orthoimages) can be generated efficiently from captured imagery, aiding in earthwork volume calculations and as-built (construction progress) management.

As shown above, RTK devices are being used across a wide range of fields from surveying and construction to infrastructure maintenance and cutting-edge drone technology. Once a specialized technique handled only by survey experts, RTK has become more accessible thanks to device miniaturization and lower costs, and more field engineers are handling RTK equipment themselves. It is expected that RTK device use cases will continue to expand across diverse work sites.

Points to consider when choosing an RTK device

Although RTK devices make high-precision positioning easy, many products exist on the market. Here are the main points to consider when adopting an RTK device.

• Positioning accuracy and GNSS support: Products differ in the GNSS systems and frequency bands they support. Models that support multiple GNSS constellations (GPS, GLONASS, Galileo, QZSS, etc.) and receive multiple frequencies such as L1/L2 tend to obtain a stable centimeter-level “fixed solution” even under poor signal conditions.

• How correction information is obtained: Required functions differ depending on whether you use a standalone setup (you set up your own base station) or a network-based service (external service). If you use a network service, the ability to receive corrections via NTRIP is essential. For use in Japan, check whether the device supports QZSS CLAS, which allows use in areas without terrestrial communications.

• Usability and interface: The usability of a dedicated controller or smartphone app is important. Because these devices are used on site, it is desirable to have simple operations that allow starting positioning and saving data easily. Japanese display and comprehensive help features give beginners peace of mind.

• Portability and durability: Since the equipment is carried around on site, compact and lightweight units are a major advantage. Check whether the device has waterproof and dustproof performance (IP rating), shock resistance, and temperature tolerance for harsh outdoor conditions. Longer battery life is also preferable for a full day of work.

• After-sales support: Support systems for surveying equipment are also important in case of trouble. Consider whether the vendor or manufacturer provides solid support channels and technical assistance, and whether long-term services such as firmware updates are available.

Taking these points into account, select an RTK device that matches your company’s needs. For first-time adopters, considering the latest models from reputable manufacturers is reassuring. Recently, high-performance yet moderately priced products have appeared, making the deployment of one device per person increasingly realistic.

Simple surveying with LRTK

Among the products driving the evolution of RTK devices, the LRTK series has been attracting attention. LRTK was developed with the concept of enabling “anytime, anywhere, anyone” to utilize high-precision positioning, and is a compact, all-in-one RTK-GNSS system. Conventional RTK equipment involved bulky stationary base stations, receivers mounted on long poles, external batteries, and radios—many components that made the setup complex. Prices were also high, making adoption difficult for small businesses. LRTK lowers those barriers and realizes RTK devices that are easy to handle on site.

A key feature of the LRTK series is miniaturization and lightweight design. For example, the smartphone-integrated “LRTK Phone” has a receiver body weighing just 125 g and a thickness of 13 mm (0.51 in), small enough to fit in a pocket. The antenna, GNSS receiver, communication module, and battery are all built in, enabling standalone centimeter-level positioning without additional wiring or external power—a versatile surveying instrument. It connects wirelessly to a smartphone via Bluetooth or Wi-Fi, making on-site handling simple. A dedicated app on the smartphone lets you check positioning results and enter point names, and the acquired data can be uploaded to the cloud for sharing on the spot. Compared with conventional RTK equipment, costs are reduced, making it realistic for on-site staff to each carry one device if needed.

Technically, LRTK incorporates the latest solutions. It supports triple-frequency GNSS reception, making it easier to obtain a stable fixed solution under multipath or ionospheric disturbances. It also supports QZSS CLAS, so even in mountain areas or at sea where mobile signals are unavailable, augmentation signals from satellites allow continued high-precision positioning. In other words, LRTK can secure RTK-equivalent positioning accuracy even when the Internet is not available. These innovations have evolved LRTK into a truly practical and easy-to-use RTK terminal for the field.

RTK positioning previously required specialist knowledge and complex hardware configurations. But with the advent of LRTK, surveying methods are changing dramatically. As a next-generation RTK device that site engineers can handle with smartphone-like ease, LRTK is promoting the democratization of high-precision positioning. If you’ve wondered, “Can I really perform high-precision surveying without specialist knowledge?”, it is worth considering a modern device like LRTK. For more details, please also visit the [LRTK official site](https://www.lrtk.lefixea.com/).

Frequently asked questions

Q. What is the difference between RTK and regular GPS positioning? A. Regular GPS (GNSS) positioning is performed with a single receiver and cannot correct the error sources contained in satellite signals, resulting in position errors of several meters. RTK, on the other hand, uses two receivers—a base and a rover—to cancel errors in real time, enabling position determination with centimeter-level accuracy. Simply put, standalone GPS gives coarse positions, whereas RTK drastically reduces positioning errors.

Q. What do I need to start RTK surveying? A. Basically, you need an RTK-capable GNSS receiver (RTK device) and a reference station system that provides correction information. If you provide your own reference station, you will need another receiver, communication equipment, and a known point setup. However, many areas now have networks of reference stations, and you can use their correction information via the Internet. In that case, with a communication environment and a contract with a correction service, you can start surveying with a single RTK receiver without setting up your own base station.

Q. Can RTK devices be used without specialist knowledge? A. Yes. Recent RTK devices are designed to be user-friendly for beginners. By following prompts on a dedicated app or controller screen, you can perform positioning without complex settings. For example, you can obtain coordinates by simply pressing a button at the desired point. However, understanding basic GPS principles and precautions is helpful for proper use.

Q. Can RTK positioning be performed in remote mountainous areas without communication coverage? A. Network RTK typically requires receiving correction data via mobile communications, so it is difficult in areas without coverage. However, RTK devices that support satellite-based augmentation such as QZSS CLAS can perform high-precision positioning even where terrestrial communications are unavailable. Alternatively, you can prepare a portable base station and transmit correction information via radio. In any case, there are methods to use RTK without mobile coverage.

Q. I’m worried whether RTK can really achieve centimeter-level accuracy. A. In theory, RTK can achieve centimeter-level accuracy, but practical accuracy depends on satellite visibility and the radio environment. In open-sky locations with stable satellite reception and communications, a centimeter-level fixed solution is obtained in most cases. However, in areas where satellite signals are disturbed—such as in the shadow of buildings or in forests—accuracy may temporarily degrade or require more time to obtain. Device performance and settings also affect results, so it is advisable to conduct a demo measurement at your actual site before adoption whenever possible.