Table of contents

• What is RTK?

• Benefits of RTK in surveying

• Benefits of RTK in construction management

• Benefits of RTK for heavy equipment operators

• Simple surveying with LRTK

• FAQ

What is RTK?

RTK stands for Real Time Kinematic, a high-precision positioning technique that uses GNSS (satellite positioning). Ordinary GPS positioning can have errors of several meters (several ft), but RTK uses a dedicated reference station (base station) and a rover (mobile unit) simultaneously to correct satellite signal errors, enabling positioning accuracy down to a few centimeters (a few in). Because results are obtained in real time, the measured positions can be used immediately on site.

In construction, this centimeter-level accuracy enables more accurate and efficient work than before. With the Ministry of Land, Infrastructure, Transport and Tourism-led push for i-Construction (ICT construction), and the increasing use of 3D data and ICT-equipped machinery, high-precision positioning by RTK is a foundational technology for on-site digital transformation. RTK-GNSS is beginning to be used in a wide range of situations, such as surveying tasks, as-built management in construction management, and machine guidance for construction equipment. Below, we summarize the specific benefits RTK brings to each profession: surveyors, construction managers, and heavy equipment operators.

Benefits of RTK in surveying

Introducing RTK into surveying work dramatically improves work efficiency and measurement accuracy. Compared with traditional methods using total stations (TS) or levels, RTK surveying offers the following advantages.

• Survey large areas in a short time: GNSS-RTK surveying requires little line-of-sight setup or instrument re-positioning. One person can walk a large site and perform continuous positioning, so topographic surveys that used to take several people a full day can be completed much faster. For longitudinal surveys in mountainous areas or ground measurements on development sites, points can be measured sequentially while moving, speeding up the entire process.

• High-accuracy data collection: RTK can position with errors within a few centimeters (a few in) both horizontally and vertically, allowing stable precision for detailed dimensions and elevations. Subtle measurements that once relied on the skill of experienced technicians can now be handled easily with RTK equipment, making as-built measurements (post-construction shape confirmation) easier to ensure quality. Because this accuracy is available in real time, it is also an advantage that results can be checked on-site as work proceeds.

• Labor-saving single-person surveying: With one RTK surveying unit, a single person can complete surveying. An assistant carrying a reflector prism is unnecessary, and there is no need to set up the instrument for each survey point. This is a major advantage in the construction industry, which struggles with labor shortages, allowing limited staff to cover sites. It also contributes to improved safety by reducing people’s exposure to hazardous areas (roadside or steep slopes).

• Easy digital utilization of data: Coordinates obtained by RTK are directly provided in a global geodetic datum (public coordinate system), simplifying transformations to local coordinates or setting known points. This makes centralized management and sharing of survey data easier and smooths importing into GIS and CAD software. Compared to the era of recording in paper field books, storing and using data digitally supports construction DX (digital transformation).

As described above, RTK is a powerful tool for surveyors. It enables high precision over wide areas in a short time, achieving efficiencies and labor savings that were difficult with total stations. The result is faster project schedules and reduced labor costs, simultaneously improving productivity and quality in surveying operations.

Benefits of RTK in construction management

For site supervisors and construction managers, introducing RTK brings many advantages. Tasks that previously relied on specialist survey teams for stakeout and as-built checks can be performed efficiently by the construction manager themselves using RTK.

• Improved accuracy in stakeout and positioning: Accurate stakeout based on design drawings is essential in construction management. Using RTK equipment allows highly accurate stake-driving based on design coordinates. Human survey errors common with tape measures or manual layout can be reduced to a minimum through digital coordinate guidance. Being able to drive stakes at the design positions prevents misalignment of foundations or road alignments, reducing rework and backtracking in later stages.

• More efficient as-built management and inspections: RTK is powerful for checking finished shapes such as embankment heights and pavement thickness. Using RTK-capable survey instruments or drones, dense as-built data over large areas can be acquired quickly. Differences from design data can be checked on the device’s screen on-site, enabling immediate decisions about additional work or corrections and reducing rework during quality inspections. Performing as-built inspections in real time and with high accuracy raises the level of quality control.

• Labor savings and cost reduction: Incorporating RTK into construction management lets fewer people handle more measurement and inspection tasks. For example, setting batter boards (stakes used as height references) or intermediate inspections normally require multiple people, but with an RTK receiver and a tablet, one manager can complete many tasks alone. If in-house staff can measure without always coordinating external survey teams, outsourcing costs and scheduling efforts decrease. RTK is an effective solution for addressing labor shortages and reducing costs.

• Improved safety and risk management: RTK use also benefits site safety management. Tasks that used to involve risks—like installing batter boards beside busy roads or surveying at cliff edges—can be checked remotely from safe locations with RTK. Drones equipped with RTK can survey steep slopes that people cannot approach. RTK equipment can also automatically record and save measurement timestamps and accuracy information, improving inspection history management and traceability. This is more reliable than paper records and makes root-cause analysis easier in case of issues.

Construction sites demand both rapid decision-making and reliable quality assurance. By enabling site supervisors to perform necessary measurements quickly and accurately, RTK supports both schedule reduction and quality improvement. Local government engineers can also use RTK for rapid and accurate damage assessments at disaster sites and for inspections of worksites. RTK is a transformative technology for construction management that enhances overall site efficiency and reliability.

Benefits of RTK for heavy equipment operators

RTK is changing the work of heavy equipment operators such as bulldozer and excavator operators. Modern machines increasingly come equipped with machine guidance / machine control; RTK-GNSS provides precise self-positioning and links with 3D design data to allow automatic or semi-automatic control of working attachments. Operators can check target heights and slopes on a monitor and perform accurate work without relying solely on experience. The advantages of RTK-enabled machine operation include the following.

• Dramatic improvement in construction accuracy: By linking RTK-positioned machine location data with digital design models, blade or bucket height and slope can be automatically adjusted. Even without a veteran’s feel, the ground can be finished to the designed elevation, producing consistently high-accuracy results. For example, site grading once required many batter boards and repeated height checks, but RTK-equipped machines can correct their own height offsets on the fly to achieve the desired finish in one pass. This reduces foundation tilt and roadbed elevation errors, greatly decreasing defects and rework.

• Increased work efficiency and shorter schedules: RTK-based automatic control enables “get it right in one pass” construction, reducing rework during heavy equipment operations. There is less need for repeated measurements or re-cutting, shortening the time required to complete the same workload. Eliminating batter boards reduces preparation days, and work interruptions while waiting for surveying are less likely. Because even less-experienced operators can work efficiently and accurately, variability in productivity due to personnel is reduced. On sites with tight schedules, RTK-equipped machines enable speedy, on-plan progress.

• Reduced personnel needs and improved safety: RTK adoption changes the traditional need for a surveyor to be near the machine to guide operations. Machine guidance allows position confirmation from the operator’s cab, reducing the need for survey personnel to enter the work area. Guidance tasks in low-visibility zones and the frequency of follow-up verification surveys decrease, lowering the risk of contact accidents. RTK thus contributes to safer operations and enables safe construction with fewer personnel. Additionally, operational data automatically recorded by the machine (what was excavated or filled, where and when) can be used directly for as-built inspections and report preparation, streamlining both fieldwork and management tasks.

• Quality not dependent on experience level: With RTK-guided operation, following the guidance on the monitor enables high-precision work, meaning operators with limited skill or experience can still achieve consistent quality. Allowing newer operators to perform near-veteran-level work raises the overall quality baseline of the team. As automation and unmanned operation of construction equipment progress, accurate RTK positioning will remain indispensable. Heavy equipment operators who master RTK will gain skills that support future smart construction.

In these ways, RTK benefits both the work performed by operators and the surrounding environment. By improving accuracy, efficiency, and safety and by delivering consistent quality regardless of skill level, RTK raises overall site productivity and safety standards. In an industry facing labor shortages and retirements of experienced personnel, RTK-capable construction is becoming the next-generation standard.

Simple surveying with LRTK

While RTK’s usefulness is clear, traditional RTK equipment has had an image of being expensive and difficult to use, creating a high adoption barrier for small construction firms and beginners. Using RTK on your own used to require high-performance GNSS receivers, radio modems, base station installation, and other specialized equipment and knowledge, so sites without sufficient investment or personnel tended to avoid it. There were also concerns about operation in mountainous areas with no cellular coverage or where satellites are hard to acquire. A solution gaining attention to address these issues and make RTK surveying easy for anyone is LRTK.

LRTK (pronounced “L-R-T-K”) is a new RTK system that combines a smartphone you already own with a compact GNSS receiver. By attaching a dedicated ultra-small receiver (a device that mounts to a smartphone) to an iPhone or iPad and connecting via Bluetooth, the smartphone becomes a centimeter-class high-precision surveying device. Whereas conventional stationary equipment weighed several kilograms and required complex radio settings, LRTK can provide high-precision positioning with a single device weighing a few hundred grams. It supports augmentation signals such as CLAS from Japan’s Quasi-Zenith Satellite System “Michibiki,” allowing standalone cm level accuracy (half-inch accuracy) even at sites without cellular coverage. This eliminates the need to install a base station or connect to the internet on site, making it easy for beginners to use.

LRTK systems bundle a variety of surveying and measurement functions needed on site into one unit. They handle single-point coordinate measurement, photogrammetry using the smartphone camera (automatically tagging photos with high-precision coordinates and orientation), wide-area point cloud measurement, and even stakeout guidance. A particularly notable feature is AR-based stakeout guidance. Design target points and directional arrows are overlaid on the smartphone camera view, so anyone can find stakeout positions without confusion. As you approach a target, guidance for fine adjustments is provided down to a few centimeters (a few in), allowing final offsets to be nearly zero. This revolutionary approach transforms conventional stakeout work that once relied on the intuition of experienced surveyors.

LRTK also integrates with cloud services, which is ideal for fieldwork. Coordinate data and photos recorded in the app are uploaded to the cloud immediately, automatically saved and shared. Team members always have access to the latest survey information, reducing the need to bring data back to the office for processing. Smartphone connectivity and cloud use make visualization and sharing of survey results easy, enabling construction managers and designers to align information in real time.

Simple surveying with LRTK makes it possible for non-specialists to perform solo, safe, high-precision surveys on site. For example, some local governments have introduced LRTK for quick post-disaster damage surveys by staff. Being able to perform tasks in-house that previously required external surveyors greatly speeds initial response and reduces costs. On construction sites, enabling each role to quickly perform their own measurements and checks reduces waiting times and improves overall productivity. The advent of LRTK has made RTK technology more accessible and user-friendly.

Compared with traditionally expensive RTK equipment, LRTK is offered at a much more affordable price point. It is now realistic for site workers to carry one device each, and small companies and younger technicians can proactively utilize high-precision positioning. With the barriers to enjoying RTK benefits lowered, trying it out is now a practical option. Consider leveraging these modern solutions to experience day-to-day efficiency and quality improvements through simple RTK surveying.

FAQ

Q: What does RTK stand for and what does it mean? A: RTK stands for Real Time Kinematic. It refers to a GNSS positioning technique that calculates high-precision positions in real time. It uses two receivers—a reference station and a rover—that receive satellite signals simultaneously and correct errors to determine positions with centimeter-level accuracy. Because positioning results are available in real time, they can be applied immediately to fieldwork.

Q: How accurate is RTK positioning? A: Typical RTK-GNSS accuracy is about 1–3 cm horizontally and about 2–4 cm vertically. In other words, horizontal error is approximately 1–3 cm (0.4–1.2 in), and vertical (height) error is around 2–4 cm (0.8–1.6 in). This is vastly more accurate than standalone GPS, which has errors of several meters. Accuracy can vary with satellite geometry and the surrounding environment. In open sky conditions with few obstructions, centimeter-level precision is stable. On site, it’s important to confirm the RTK solution mode (Fixed vs. Float) and record data only when accuracy is ensured.

Q: What equipment and preparations are required to introduce RTK? A: For conventional RTK, the following are basically required:

• GNSS receiver (rover): A high-precision device compatible with GPS/GLONASS/Michibiki. Typically mounted on a survey pole.

• Reference station: A fixed GNSS receiver installed at a known coordinate. It needs radio communication capability to the rover (radio modems, UHF radios, etc.).

• Communication environment: Radio communication between the reference station and the rover (or internet connection for network RTK).

• Survey controller: A terminal to display and record data (dedicated controller or tablet).

• Accessories such as power supplies and tripods: Batteries for outdoor use and tripods for fixing the base station.

Network RTK services that receive correction data from networks such as the Geospatial Information Authority of Japan’s stations are also now common. In that case, a private base station is unnecessary, but the rover must connect to the service via the internet, so cellular communication on site is required. On the other hand, modern systems like LRTK only need a small receiver and a smartphone, so the large-scale preparations of the past are not necessary. Choose the method that fits site needs and budget.

Q: Can RTK be used in mountainous areas without cellular reception? A: Yes. There are two primary methods. One is to set up your own reference station and transmit corrections directly; this enables RTK without relying on cellular networks. The other is to use services such as CLAS (Centimeter-Level Augmentation Service) provided by Japan’s Quasi-Zenith Satellite System “Michibiki.” CLAS-compatible receivers can achieve high-precision positioning from satellites even in mountainous areas. LRTK supports CLAS, so it can perform standalone cm level accuracy (half-inch accuracy) in areas without cellular coverage. However, in mountainous terrain, satellites themselves may be difficult to acquire if sky visibility is poor, so ensure sufficient overhead visibility.

Q: Can someone with no surveying experience operate RTK? A: While traditional professional RTK equipment required operational knowledge and understanding of principles, user-friendly products have increased recently. Smartphone-linked systems like LRTK present intuitive guidance in apps and simple button operations, so users without specialist knowledge can perform high-precision positioning. AR stakeout features can be almost game-like in ease of use. With a basic understanding of GPS positioning, short training is often enough to deploy staff to the field. Of course, maintaining accuracy requires some skills (checking satellite reception and handling error sources), but following manufacturer instructions and support makes it manageable. It’s becoming an era where even young construction managers can leverage RTK.

Q: Isn’t RTK equipment expensive to introduce? A: High-precision GNSS receivers used to be very expensive and seemed only affordable to large companies. However, technological advances and wider adoption have significantly reduced costs. Network RTK services have monthly fees, but reducing outsourcing survey costs can justify the investment. New solutions like LRTK are available at a fraction of the cost of conventional equipment. They are designed to minimize maintenance and training burdens in addition to lower initial costs. Products affordable to small companies are now on the market, so don’t dismiss RTK as out of reach—request quotes and consider options. In many cases, labor cost savings and schedule reductions make the investment pay off.