Table of Contents

• What is RTK surveying?

• On-site problem 1: Cable hell

• On-site problem 2: Too much equipment

• Advances in RTK technology that solve cable and equipment problems

• Simplified surveying with LRTK

• FAQ

Have you ever set up RTK equipment at a survey site and struggled with tangled cables or hauling heavy gear back and forth? RTK surveying is an innovative technology that delivers millimeter-level accuracy, but it also brings the familiar on-site headaches described above — the typical “on-site problems.” The stress on field workers caused by大量のケーブル配線や機材の持ち込み (大量の is left untranslated to maintain fidelity?) and handling many pieces of equipment is by no means trivial. This article addresses these RTK site challenges, explains their causes and solutions, and finally introduces a new simplified surveying device, LRTK, which frees you from many of these problems.

What is RTK surveying?

RTK stands for Real Time Kinematic, a method of real-time high-precision positioning using GNSS satellites. Ordinary GPS positioning can have errors of several meters, but RTK surveying uses two receivers — a base station (fixed station) and a rover (mobile station) — and corrects the rover’s positioning errors using the base station’s accurate position data. As a result, it delivers dramatically higher accuracy, typically within a few centimeters both horizontally and vertically. One major advantage of RTK is that it can provide millimeter- and centimeter-level accuracy immediately with GPS/GNSS, accuracy that previously required a total station.

High-precision RTK surveying is indispensable where precise positioning is required, such as verification of civil engineering work or stakeout for pile driving. However, operating RTK equipment on site also involves on-site-specific hassles. The next section looks at two representative examples: “cable hell” and “too much equipment.”

On-site problem 1: Cable hell

When operating RTK surveying in the field, the first thing you often face is an environment full of cables. When you set up a base station, you need multiple cables to connect the receiver body to the antenna and wireless devices, and if you use external power, additional wiring to batteries is required. Cables crawling around the tripod obstruct movement and pose safety risks. Many have experienced receivers being knocked over by wind catching a cord, or workers tripping over cables.

Even more troublesome are malfunctions caused by cable breaks or poor contacts. In harsh outdoor environments, cable jackets deteriorate and connectors loosen, which can interrupt communications and prevent RTK correction data from being received. As a result, positioning can become unstable, and if a FIX solution cannot be obtained, equipment set up at the site may become useless. A single faulty cable can stop the whole operation, so crews must always carry spare cables and repair kits, adding extra burdens.

In recent years, wireless data communication and Bluetooth connections have become more common, and cable-free setups are gradually advancing. However, many sites have not yet completely escaped “cable hell.” In particular, base stations often opt for wired connections for stability, so wiring work remains. The stress of cables tangling when you need to move quickly on site is a typical RTK surveying complaint.

On-site problem 2: Too much equipment

The large amount of equipment required for RTK surveying is another major factor that troubles fieldwork. A typical RTK system requires GNSS receivers for both the base and rover, plus radio modems or antennas for stable communication, and a dedicated surveying controller — many devices to carry. Just transporting and setting up these items is a challenge, and in mountain areas where vehicles cannot reach, you may have to make many trips on foot.

Having lots of equipment increases weight and setup time. Large fixed GNSS receivers and high-capacity batteries for long operation are heavy and drain physical stamina during transport. After arriving on site you must mount tripods, set up the base station, connect and start each device, which takes a long time. These preparations can’t be skipped even when weather is worsening or work time is limited. As a result, the honest feeling at many sites is, “I’m exhausted before we even start surveying.”

Handling multiple devices also increases items to manage: battery charge levels, device checks, preventing leaving equipment behind — many points require attention. More equipment raises the risk of trouble; for example, “the controller terminal was updating its software and couldn’t be used,” or “the radio modem settings didn’t match and could not connect,” causing unexpected delays. While RTK surveying is attractive for its high accuracy, the complexity of handling many devices simultaneously has long troubled field crews.

Advances in RTK technology that solve cable and equipment problems

To address the wiring complexity and equipment overload described above, RTK technology continues to evolve. Two notable recent trends are the advancement of wireless communication technology and the miniaturization and integration of surveying equipment.

On the communications side, methods to obtain RTK correction information have diversified. Traditionally, users broadcast correction data from their own base station, but network RTK delivered via the internet has become widespread. This uses data from networks of reference stations, such as the Geospatial Information Authority’s permanent reference point network, obtained over cellular networks, so users don’t need to provide their own base station. On-site, you may only need to bring the rover receiver, eliminating the need to carry a full base station setup and thus reducing carried equipment. Since communications can use a smartphone or tablet rather than a radio modem, it eliminates complicated wiring and dedicated radio setup.

In Japan, the quasi-zenith satellite “Michibiki” provides a free high-precision positioning service, CLAS (Centimeter Level Augmentation Service). CLAS-compatible GNSS receivers can receive correction information directly from satellites, so internet communication isn’t even necessary on site. Even in mountain areas without cellular coverage or when concerned about communication costs, RTK positioning can be completed by satellite communication alone. This revolutionary system eliminates the need for base station radios or communication terminals and can greatly reduce required equipment and cables.

The miniaturization and performance improvements of devices themselves are also noteworthy. The latest GNSS receivers support multi-GNSS and multiple frequencies, enabling stable FIX solutions even in harsh outdoor conditions, while becoming more compact. In particular, the advent of small surveying devices that link with smartphones is dramatically changing field practice. Smartphones provide high-performance communication and computing capabilities, which can replace roles previously handled by dedicated equipment. For example, you can operate a receiver and record data via a smartphone app without a dedicated controller, reducing excess equipment. Combining smartphone cameras and AR technology with surveying data enables new applications that streamline field documentation.

Field operational efficiency has also improved. Tasks that previously required a surveying team, such as as-built verification or setting out, can increasingly be handled by on-site personnel using compact surveying devices. This reduces construction stoppages while waiting for surveying and minimizes communication losses, enabling quick solo surveying and improving productivity. Devices that are intuitive for less-experienced technicians also help address labor shortages and facilitate skill transfer.

Thus, through wireless communications (cable-free setups) and device integration, RTK surveying is evolving toward a model where “you only need to bring what’s necessary” to the site. The next section introduces LRTK, a leading-edge solution that exemplifies this evolution and shows how it frees you from cable hell and excessive equipment.

Simplified surveying with LRTK

One of the latest devices embodying the technical trends above is LRTK. Developed by a startup from Tokyo Institute of Technology, LRTK is a high-precision GNSS surveying device series of ultra-compact RTK receivers used in conjunction with a smartphone. The flagship model, the “LRTK Phone,” realizes full-scale RTK surveying simply by attaching a receiver weighing approximately 125 g and about 13 mm (0.51 in) thick to an iPhone. Centimeter-level positioning that previously required a fixed base station and large antenna can now be achieved with just a smartphone and a palm-sized device — a revolutionary approach.

With LRTK, you are free from troublesome cable connections. The smartphone and the LRTK device operate as an integrated unit, with data transmission handled seamlessly via Bluetooth or similar methods, eliminating wiring from the receiver to the phone. The LRTK device itself has an internal battery, so no external power cable is needed. To start surveying on site, you simply tap a button in the dedicated app to begin measurements. Without time spent on complex settings or checking inter-device wiring, you can start cable-free, comfortable surveying.

In terms of equipment, LRTK dramatically reduces what you need to bring to the site. Because you don’t need your own base station, surveying can be completed with basically a single set: a smartphone + an LRTK device. Compared to traditional high-priced surveying equipment, LRTK’s lower acquisition cost is also attractive. By utilizing the free CLAS service, running costs such as communication fees can be minimized. This makes LRTK accessible to small and medium-sized construction and surveying firms, allowing them to benefit from the latest technologies. LRTK devices support multi-GNSS and are designed for high sensitivity; their accuracy is approximately horizontal ±2 cm (±0.8 in) and vertical ±3 cm (±1.2 in), comparable to traditional fixed equipment. Moreover, LRTK supports the aforementioned CLAS, allowing correction signals to be received directly from satellites. In other words, the LRTK device alone can obtain a FIX solution even in remote mountains or islands (where communication coverage is available, you can of course use network RTK services via your smartphone). This eliminates the need to prepare radio modems or extra communication devices.

LRTK also improves field mobility. Being small and lightweight, workers can carry it in a pocket and take it out for quick positioning when needed. There is no need for multiple people to carry heavy tripods and equipment cases; one person can complete surveying easily. Some LRTK models are dust- and water-resistant and offer tilt compensation, enabling reliable measurements in harsh environments or when a pole cannot be held perfectly vertical. Points that were previously impossible to survey due to obstacles can now be measured, increasing operational flexibility.

Another advantage of smartphone integration is automatic recording and sharing of measurement data. When you press the measurement button in the LRTK app, the coordinates for that point are instantly calculated, plotted on a map, and saved to the cloud. There is no need to copy numbers into paper field books, reducing measurement errors and the risk of data loss. If you take photos with the smartphone camera, the photo’s coordinates and orientation are automatically tagged, simplifying field photo management. With just one smartphone you can complete surveying and documentation — LRTK greatly reduces not only cable and equipment hassles but also the burden of field recordkeeping.

LRTK overturns conventional wisdom about RTK surveying and transforms field surveying styles. By freeing you from cable hell and minimizing equipment, it contributes significantly to shorter work times and productivity gains. Such labor-saving measures align with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative (promoting ICT use in construction sites), and LRTK is an advanced solution that supports DX in the construction industry. On your site, LRTK can become a reliable partner that “changes the norms of surveying.”

That concludes our overview of RTK field challenges and their solutions. Below is a Q&A summarizing frequently asked questions about RTK and LRTK for your reference.

FAQ

Q: What is RTK? A: RTK (Real Time Kinematic) is a technology that uses GNSS to perform real-time high-precision positioning. By comparing satellite observations from a base station and a rover in real time and correcting errors, RTK reduces the meter-level errors of ordinary GPS down to centimeter-level errors. It is widely used in surveying and construction where millimeter- or centimeter-level accuracy is required.

Q: What equipment is needed for RTK surveying? A: Traditional RTK surveying requires at least two GNSS receivers, one for the base station and one for the rover. In addition, communication equipment (e.g., radio modems) to send correction information from the base to the rover, a controller terminal to display and operate positioning results, and batteries for long operation are typically combined and operated. However, network RTK, which obtains corrections from a government- or region-operated reference station network over the internet, has become common and can eliminate the need for your own base station in some cases. New products that combine a smartphone and a small receiver can also greatly reduce required equipment.

Q: What common problems occur on RTK surveying sites? A: One main problem is the abundance of cables. Wiring between the base station and devices is often complex and causes handling problems and failures. Another is the quantity and weight of equipment, which increases the effort to transport and set up multiple expensive devices and the number of tasks to manage. Other hurdles include reliance on skilled operators due to specialized knowledge and high initial costs. Improvements in communication technology and device miniaturization are being pursued to solve these issues.

Q: What is LRTK? A: LRTK is a new RTK surveying system composed of a small high-precision GNSS receiver and a smartphone app. Developed by a startup from Tokyo Institute of Technology, it uses a palm-sized receiver that attaches to a smartphone. It enables real-time centimeter-level positioning and supports satellite augmentation signals (CLAS), making it much easier to handle than conventional RTK equipment.

Q: Is RTK surveying possible with a smartphone? A: Yes. Recently, small RTK receivers that pair with smartphones have appeared, allowing high-precision positioning without dedicated surveying equipment. LRTK is a representative example: attach it to a smartphone to avoid wiring and hauling heavy gear. Surveying can be performed by pressing a button on the smartphone app, and data is automatically saved to the cloud, creating a very streamlined workflow. RTK surveying that previously required specialized devices is becoming doable with a single smartphone.

Q: What is CLAS? A: CLAS (Centimeter Level Augmentation Service) is a high-precision positioning service provided by Japan’s quasi-zenith satellite system “Michibiki.” It broadcasts correction information created from terrestrial reference station data nationwide on the L6 band, and compatible receivers can achieve centimeter-level positioning without the internet. The service is free and enables RTK surveying even in areas without cellular coverage (compatible devices are required).

Q: What is i-Construction? A: i-Construction is an initiative by the Ministry of Land, Infrastructure, Transport and Tourism to improve productivity by promoting ICT use on construction sites. It comprehensively advances drone surveying, the use of 3D design data, machine-control construction, and the introduction of high-precision GNSS positioning technologies, aiming to streamline construction, reduce labor, and improve quality. Technologies like RTK and LRTK contribute to realizing the smart sites i-Construction seeks.