Solving RTK's "On-site Realities": Freeing You from Cable Hell and Excess Equipment

Table of Contents

• What is RTK surveying?

• On-site reality 1: Cable hell

• On-site reality 2: Too much equipment

• Advances in RTK technology that solve cable and equipment issues

• Simplified surveying with LRTK

• FAQ

Have you ever set up RTK equipment on a survey site and struggled with tangled cables or repeatedly carried heavy gear? RTK surveying is an innovative technology that delivers millimeter-level accuracy, but it also comes with the familiar on-site frustrations described above—what we call the on-site "common problems." The stress experienced by field workers who are forced to deal with大量のケーブル配線や機材の持ち込み (large amounts of cable wiring and bringing in equipment) is far from trivial. This article addresses those RTK surveying challenges, explains their causes, and describes solutions. Finally, we introduce a new simplified surveying device, LRTK, which can free you from those burdens.

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 based on the base station’s accurate position information. As a result, it can achieve dramatically higher accuracy, with both horizontal and vertical errors within a few centimeters. A major advantage of RTK is that it delivers millimeter- to centimeter-level accuracy with GPS/GNSS in real time—accuracy that previously required a total station.

High-precision RTK surveying is indispensable for tasks that require precise positioning, such as checking civil engineering work or setting stakeout positions. However, operating RTK equipment in the field also involves on-site difficulties. In the next section, we’ll look at two representative issues: “cable hell” and “too much equipment.”

On-site reality 1: Cable hell

When operating RTK in the field, one of the first things you face is a cable-filled environment. Once you set up a base station, you need several cables to connect the receiver unit to the antenna and radio equipment, and if you use an external power supply, wiring to batteries is required too. The cables snaking around the tripod get in the way of footing and pose safety risks. Many have experienced wind whipping cables and knocking over a receiver, or workers tripping over cords.

Even more troublesome are troubles caused by cable breaks or poor connections. In harsh outdoor environments, cable jackets can degrade and connectors can loosen, causing communications to drop and RTK correction information to stop being delivered. As a result, positioning can become unstable or the FIX solution may not be obtained, rendering the installed equipment useless at the site. A single faulty cable can halt the entire operation, so field crews must always keep spare cables and repair kits on hand, adding unnecessary hassle.

Wireless data communications and Bluetooth have been spreading in recent years, gradually reducing cabling. However, many sites have not yet completely escaped “cable hell.” In particular, base stations are often wired for stability, so the burden of cabling work remains. The stress of cables getting tangled when you want to move nimbly on site is a typical RTK surveying pain point.

On-site reality 2: Too much equipment

The sheer amount of equipment required for RTK surveying is another major on-site headache. A typical RTK system requires GNSS receivers for both the base and rover, plus radio modems and antennas for stable communication, and dedicated surveying controller terminals—there are many devices you have to carry. Transporting and setting these up at the site is a chore, and in mountainous areas where vehicles can’t reach, you may have to make multiple trips by hand.

Having many devices increases weight and setup time. Large, stationary GNSS receivers and high-capacity batteries for long operation are heavy and wear down your physical energy when carrying them on site. After arriving, you must mount a tripod for the base station, install it, connect and start various devices—which takes considerable time. You can’t skip this preparation even when bad weather is approaching or you have limited working time. The honest feeling at the site is often, “I’m tired before I even start surveying.”

Handling multiple devices also increases the number of management items. You must monitor battery charge levels, check each device’s operation, and avoid forgetting to bring equipment to the site—there are many points that require attention. The more devices you have, the higher the risk of trouble. For example, “the controller terminal’s software was updating and couldn’t be used,” or “the radio modem settings didn’t match and couldn’t connect,” causing unexpected delays. While RTK surveying is attractive for its high precision, the complexity of handling many devices simultaneously has long troubled field teams.

Advances in RTK technology that solve cable and equipment issues

To solve the cabling complexity and equipment overload described above, RTK technology is continually evolving. Two notable recent trends are the advancement of wireless communication technologies and the miniaturization and integration of surveying equipment.

On the communications side, methods for obtaining RTK correction information have diversified. Traditionally, it was common to broadcast correction data from a privately managed base station, but today network RTK—distributing correction information via the Internet—has become widespread. This method acquires data from networks of reference stations installed across regions, such as the Geospatial Information Authority of Japan’s electronic reference point network, via cellular lines, so users don’t need to provide their own base station. On site, you often only need the rover receiver, eliminating the entire base station setup and thus reducing the amount of equipment to carry. Since communications can use a smartphone or tablet rather than a radio modem, the cumbersome wiring and dedicated radio setup are unnecessary.

In Japan, the quasi-zenith satellite “Michibiki” provides a free high-precision positioning service called CLAS (Centimeter Level Augmentation Service). CLAS-compatible GNSS receivers can receive correction information directly from satellites overhead, so Internet communication is unnecessary at the site. Even in mountainous areas without cellular service or where communication costs are a concern, RTK positioning can be completed using satellite signals alone. This revolutionary approach eliminates the need for base station radios and communication terminals, significantly reducing required equipment and cables.

The miniaturization and performance improvements of devices themselves are also noteworthy. The latest GNSS receivers support multi-GNSS and multi-frequency, offering reliable FIX solutions even in harsh outdoor environments while becoming more compact. The emergence of small surveying devices that work with smartphones is particularly changing field practices. Smartphones have high-performance communications and computing capabilities, and combining them with receivers can replace roles once filled by dedicated equipment. For example, you can operate a receiver and record data with a smartphone app without a dedicated controller, reducing unnecessary gear. The fusion of smartphone cameras and AR technology with survey data also enables new on-site recording efficiencies.

Field work efficiency is also improving. Tasks like as-built checks and stakeout that used to require a surveying team can now often be handled by on-site personnel using small surveying devices. This reduces delays due to waiting for surveyors and cuts down communication loss, enabling one person to survey quickly and improving productivity. Intuitive devices that even inexperienced technicians can use help address labor shortages and support skill transfer.

In these ways, leveraging wireless communications (going cable-free) and device integration is moving RTK surveying toward a model where you only need to bring what’s necessary to the site. In the next section, we’ll introduce LRTK, a cutting-edge solution that exemplifies this trend and explain specifically how it frees you from cable hell and excessive equipment.

Simplified surveying with LRTK

One of the latest devices embodying the trends above is LRTK. Developed by a startup originating from the Tokyo Institute of Technology, LRTK is a high-precision GNSS surveying device series of ultra-compact RTK receivers designed to be used in conjunction with a smartphone. The flagship model, the “LRTK Phone,” achieves full-fledged 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 formerly required a stationary base station and large antenna is now possible with just a smartphone and a palm-sized device—an innovative approach.

With LRTK, you can forget about troublesome cable connections. The smartphone and LRTK unit operate as an integrated system, and data transmission is handled seamlessly by Bluetooth or similar means, so no wiring from the receiver to the smartphone is required. The LRTK unit also has a built-in battery, eliminating the need for external power cables. To start positioning on site, you simply tap a button in the dedicated app to begin measurement. Without spending time on complex settings or checking cable connections between devices, you can start comfortable cable-free surveying.

LRTK also dramatically reduces the gear you bring to the field. Because you don’t need your own base station, surveying operations can be completed with a single set: a smartphone plus an LRTK unit. Additionally, the initial cost is lower compared with conventional expensive surveying equipment. By using free CLAS, running costs such as communication fees can be kept minimal. This makes LRTK accessible for small- to medium-sized construction companies and surveying firms to adopt and benefit from the latest technology. LRTK units support multi-GNSS and high-sensitivity design, offering accuracy around horizontal ±2 cm (±0.8 in) and vertical ±3 cm (±1.2 in), comparable to traditional stationary equipment. Moreover, LRTK supports the aforementioned CLAS, allowing it to receive correction signals directly from satellites overhead. In other words, LRTK units can obtain a FIX solution by themselves even in deep mountains or remote islands (of course, where communication is available, you can also use network RTK services via your smartphone). This eliminates the need to prepare radio modems or other communication devices.

LRTK also enhances field mobility. Because the device is small and lightweight, workers can carry it in a pocket and take it out for positioning whenever needed. There’s no need for multiple people to carry heavy tripods and equipment boxes—one person can easily complete surveying. Some LRTK models feature dustproof/waterproof designs and tilt compensation, enabling reliable measurements even in harsh environments or when you cannot hold a pole perfectly vertical. Points that were previously unmeasurable due to obstructions can now be surveyed, increasing operational flexibility.

Another advantage of smartphone integration is automatic recording and sharing of measurement data. Pressing the measurement button in the LRTK app instantly computes the coordinates for that point, plots it on a map, and saves it to the cloud. There is no need to transcribe numbers into a field notebook, which reduces measurement errors and the risk of data loss. If you take photos with the smartphone camera, the photo automatically tags coordinates and orientation, making it easy to organize site photos. With a single smartphone handling surveying and recording, LRTK greatly reduces not only the hassle of cables and equipment but also the burden of site documentation.

LRTK overturns conventional wisdom about RTK surveying and renews field surveying practices. By freeing you from cable hell and minimizing equipment, it significantly shortens working time and improves productivity. This kind of labor saving aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative to promote ICT use in construction sites, and LRTK can be seen as an advanced solution that supports the construction industry’s digital transformation. On your site, LRTK could become a reliable partner that changes the “conventional wisdom of surveying.”

That concludes our introduction to RTK surveying field issues and their solutions. Below is a Q&A summarizing common questions about RTK and LRTK for your reference.

FAQ

Q: What is RTK? A: RTK (Real Time Kinematic) is a technique that uses GNSS to perform high-precision positioning in real time. By comparing satellite observations from two receivers—the base station and the rover—in real time and correcting errors, RTK reduces the meter-level errors typical of ordinary GPS to around 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—for the base station and the rover. You also need communication equipment (such as 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—multiple devices are combined for operation. However, network RTK, which obtains correction information via the Internet from government- or region-operated reference station networks, has become widespread and can eliminate the need for a private base station. Newer products that combine a smartphone with a small receiver can dramatically reduce required equipment.

Q: What are common challenges in RTK surveying in the field? A: One major challenge is the abundance of cables, which complicates wiring between base stations and devices and causes handling issues and trouble on site. Another is the number and weight of devices, which make transport and setup burdensome and increase the number of tasks to manage. Other hurdles include reliance on skilled operators due to required expertise and high initial costs. Improvements in communications 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 the Tokyo Institute of Technology, it uses a palm-sized receiver “LRTK unit” attached to a smartphone. It enables real-time centimeter-level positioning and supports satellite augmentation signals such as CLAS, making it much easier to handle than traditional RTK equipment.

Q: Is RTK surveying possible with a smartphone? A: Yes. Recently, small RTK receivers that work 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 carrying heavy equipment. Measurements can be started with a tap in the app, and data are automatically saved to the cloud, creating a very streamlined workflow. The era is coming when RTK surveying that once required specialized devices can be performed easily 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 “Michibiki.” It broadcasts error correction information nationwide on the L6 band based on data from terrestrial electronic reference points, enabling centimeter-level positioning without the Internet when using a compatible receiver. The service is free and allows RTK surveying even in areas without cellular coverage (a compatible receiver is required).

Q: What is i-Construction? A: i-Construction is an initiative by the Ministry of Land, Infrastructure, Transport and Tourism to improve productivity in construction sites through ICT. It promotes integrated use of drone surveying, 3D design data, machine-control construction, and high-precision GNSS positioning, aiming to streamline work, reduce labor, and improve quality. Cutting-edge technologies like RTK surveying and LRTK contribute to realizing the smart sites i-Construction envisions.