Achieving One-Person Layout with LRTK: Improving Survey Work Efficiency and Reducing Labor

Table of Contents

• Background: Why one-person layout is needed

• Traditional layout methods and challenges

• What is one-person layout using RTK?

• Benefits of RTK one-person layout

• Notes and limitations of RTK layout

• Latest technologies supporting one-person layout

• Simple surveying with LRTK

• FAQ

Background: Why one-person layout is needed

Layout (sokusetsu) is the work of accurately transferring the locations and dimensions of buildings and structures drawn on design drawings to the actual site. Known as marking-out or placing batter boards, it is an indispensable and important process in construction, and it is a delicate task where errors of a few centimeters (a few in) can have a major impact on subsequent work. Traditionally, this layout work was carried out by a skilled surveying team of two people. For example, one person sets up and aims a surveying instrument (such as a total station) while the other stands at the survey point holding a staff or prism.

However, in recent years the construction industry has been facing a serious labor shortage and an aging workforce, creating situations where sites must be operated with limited personnel. Veteran surveyors are retiring one after another while fewer young people are joining the profession, making securing personnel for layout work a major issue. Demand for civil engineering and building work continues unabated, so improving efficiency and reducing labor is urgent to carry out the necessary surveying and layout work without interruption.

Against this backdrop, a new style—“layout that can be done by one person”—has come to be strongly demanded. If layout work can be completed by one person without forming a surveying crew, surveying can continue even on sites chronically short of personnel. Reducing the arrangements and waiting time for multiple people allows layout to proceed in parallel with other work, improving overall site productivity. For example, in situations where heavy equipment operators used to wait for the surveying crew to arrive, one-person layout can greatly shorten waiting time and reduce schedule losses. If a system is in place that allows anyone to perform layout immediately when needed, sites can respond flexibly to bad weather or schedule changes. A system that does not rely on specific craftsmen or surveyors is also effective for risk distribution and safety management on site.

Policies such as *i-Construction* promoted by the Ministry of Land, Infrastructure, Transport and Tourism provide tailwinds, accelerating the trend toward performing work with fewer people through digital technology. One-person layout is not only a trump card for solving labor shortages but also an innovative effort symbolizing on-site DX (digital transformation).

Traditional layout methods and challenges

Conventional layout work relied on manpower and optical surveying instruments. Survey crews used measuring tapes and total stations (TS) to calculate stake positions from drawing coordinates and set markers such as batter boards and stake marks on site. However, this method has several challenges. First, line-of-sight must be secured. When using a TS, accuracy becomes difficult if obstacles block the line between measurement points. If buildings or earthworks block the view, the instrument must be repositioned, reducing efficiency. On large sites requiring long-distance layout, line-of-sight limitations require multiple setups.

Weather and terrain conditions also affect measurements. Rain or strong winds can reduce measurement accuracy, and setting up equipment or driving stakes in unstable footing can be hazardous. Having personnel determine stake positions in areas where heavy machinery is operating is also risky for safety and burdens the workers. To solve these inefficiencies and dangers of traditional methods and enable anyone to perform layout quickly and safely, a new method using RTK positioning is attracting attention.

What is one-person layout using RTK?

RTK (Real-Time Kinematic) positioning is a positioning method that uses two GNSS receivers (a base station and a rover) to correct positioning errors in real time, enabling position determination with centimeter-level accuracy. The base station is set up at a point whose coordinates are known in advance; it calculates the deviation (error) between the satellite signal and the known position and transmits this as correction information. The rover receives that correction information and applies it to its own positioning data, canceling out errors that would otherwise be several meters to the order of a few centimeters. It is far more precise than standard GPS surveying and can meet the accuracy (a few centimeters (a few in)) typically required for general civil engineering and construction work.

Using RTK positioning for layout eliminates the need for direct line-of-sight that was necessary before. As long as the base station and rover can receive satellite signals, coordinates for any point can be obtained even across obstacles. Therefore, an operator (surveyor) can carry an antenna and walk around the site, matching their current position to the specified coordinates and marking or staking the target points. One person carrying an antenna can move and perform high-precision layout, making it highly mobile even for widely spaced survey points. In other words, the roles of “person operating and waiting with the surveying instrument” and “person standing at the target point” become unnecessary, enabling a new layout style that can be completed by one person.

Benefits of RTK one-person layout

By leveraging RTK technology, one-person layout offers many benefits. The labor-saving and speed advantages of modern digital surveying directly improve site productivity. The main advantages are summarized below.

• Labor savings and personnel reduction: Because layout work can be completed by one person, there is no need to allocate multiple people for staking or as-built measurements. Even sites struggling with personnel shortages can handle the necessary surveying tasks with a minimal crew.

• Time savings and efficiency improvements: Large-scale equipment setup and personnel arrangements are no longer required, so layout can begin as soon as the decision is made. With less preparation and waiting time, working hours are shortened and the efficiency of the entire process improves. Also, because positioning data is automatically recorded and shared digitally, post-processing and reporting are faster.

• High-precision positioning: RTK-GNSS provides positioning accuracy on the order of a few centimeters (a few in). Even compact, easy-to-handle devices can acquire high-precision data, ensuring adequate quality for stake placement and as-built management.

• Portability and mobility: Because pocket-sized small devices can be used, moving and carrying equipment on site is easy. One person can freely reach high, confined, or distant measurement points, enabling flexible response to any situation.

• Improved safety: Minimizing surveying personnel reduces the number of people entering hazardous areas such as zones with operating heavy machinery. Also, because staking work can be completed quickly, exposure time in high-traffic road work or other risky locations is reduced, lowering risk.

• Low-cost introduction: Compared with traditional high-precision optical surveying instruments, RTK-compatible small GNSS devices and related software are relatively inexpensive. Small-scale contractors who could not afford costly equipment can adopt them, reducing the burden of maintenance costs.

• Ease of data utilization: Because positioning results are obtained as digital data from the start, they can be directly imported into CAD drawings or 3D models. This eliminates the need to re-enter numbers scribbled in field notebooks, and data can be shared instantly with stakeholders via the cloud, enabling smooth information linkage from surveying to design and construction management.

Notes and limitations of RTK layout

Even convenient RTK one-person layout has points to note and limitations. First, it is greatly affected by the GNSS satellite signal reception environment. Sites surrounded by high-rise buildings in urban areas, forests with dense trees, or under bridge girders tend to have signals blocked, making positioning unstable. In some cases, temporary errors of several tens of centimeters (several tens of in) can occur, or a fixed solution may not be obtained and only a float solution (an unstable solution) remains. In such environments, do not force staking using only RTK; it is advisable to double-check positions by combining traditional total station surveying or batter board layout.

Next, attention must be paid to the required accuracy levels. For general civil construction, RTK accuracy of about 2–3 cm (0.8–1.2 in) horizontally can handle most layouts, but critical processes that require millimeter-level accuracy—such as laying out column centers for steel erection or pile center positioning for bridge foundations—pose risks if relying solely on RTK. In such cases, it is ideal to use RTK to obtain approximate positions and then perform final fine alignment with a TS or optical level, ensuring accuracy in two stages. For critical points, thorough final checks are essential; a realistic approach is to save labor with RTK while using conventional methods for the final fine-tuning.

Furthermore, stable use of RTK positioning requires familiarity with equipment handling and positioning techniques. Recent RTK devices and dedicated apps are user-friendly and easy to operate, but basic practices—such as holding the antenna vertically, setting the measurement height correctly, and constantly checking satellite reception—remain necessary. When using devices for the first time, do not immediately use them for actual staking; practice in open locations to get a sense of positioning accuracy trends. With gradual experience, you will be able to confidently use RTK layout on site.

Latest technologies supporting one-person layout

Rapid advancements in surrounding technologies over the past few years have made RTK one-person layout a practical and spreading method. The following technological innovations have been major turning points.

• Compact surveying equipment and smartphone integration: In the past, centimeter-accuracy GNSS surveying equipment was typically stationary, weighing several kilograms and costing a lot. Today, handheld high-performance GNSS receivers combined with smartphones or tablets have appeared as small RTK positioning systems. The smartphone serves as the control screen and communication terminal while the small receiver performs high-sensitivity positioning, making RTK surveying easy to perform even without specialized knowledge. No cable connections or complicated settings are required, and the convenience of turning on the device on site and starting measurement immediately is revolutionary.

• Network RTK and satellite augmentation services: In Japan, network RTK (VRS and similar methods) using the Geospatial Information Authority’s reference station network is becoming widely available. As long as you have a compatible GNSS receiver and a communication line, you can obtain correction information via the Internet without installing your own base station on site, enabling real-time centimeter-level positioning. In addition, the Quasi-Zenith Satellite System “Michibiki” has begun offering centimeter-level augmentation services (CLAS), allowing RTK positioning with augmentation signals from satellites alone even in mountainous regions or remote islands where mobile signals do not reach. With these infrastructures, one-person RTK surveying, which used to be difficult, has become much more accessible.

• Intuitive navigation using AR: AR (augmented reality) technology is also strongly supporting one-person layout. By overlaying design positions and guiding arrows on the camera view of a smartphone or tablet, the screen alone intuitively shows where to place stakes. It feels like a “navigation system for layout,” guiding even inexperienced workers to the correct point without hesitation. For example, simply walking around the site with a tablet will display remaining distance such as “x cm to go,” and when the correct position is reached, an on-screen marker will visually align with the stake position on the ground. By combining the high precision of RTK with AR visualization, an era is approaching where anyone can easily and accurately perform staking and marking-out.

Simple surveying with LRTK

To fully leverage the benefits of RTK technology, the existence of easy-to-use equipment and systems is important. Traditionally, performing RTK surveying on site required expensive special equipment and complicated settings, but now solutions like LRTK make it easy for anyone to adopt RTK surveying. LRTK is an all-in-one surveying system that combines a compact high-performance GNSS antenna that can be attached to a smartphone or tablet, a dedicated app, and cloud services. The receiver, weighing about 125 g and about 13 mm thick (0.51 in), integrates an antenna, a high-performance GNSS chip, a battery, and a communication module; attaching it to a smartphone and launching the app starts centimeter-level positioning. Compared with traditional RTK equipment, there is no need for cable connections or complex initial setup, and it is intuitive to operate even without surveying expertise.

For example, using LRTK enables even those with limited surveying experience to perform everything from simple as-built measurements to precise stake positioning. Staking work that used to require a two-person team can now be reliably guided to the correct positions by a single person using LRTK’s AR navigation features. The introduction barrier for RTK-only surveying has been significantly lowered for small and medium construction companies and local governments thanks to the LRTK series. As a modern RTK solution compatible with *i-Construction*, it is attracting attention as a tool that dramatically improves site productivity and surveying accuracy.

If you want to perform staking measurements alone using RTK but are unsure what to prepare, LRTK provides the necessary device, app, and cloud environment as a complete package, making adoption smooth. It is also considerate of pricing and operation, so companies without dedicated surveying departments can handle it easily. As RTK becomes more widespread, surveying work is expected to transform from a “craftsman’s skill” into a “task anyone can do” through digital technology. As a forerunner, simple surveying with LRTK has the potential to greatly change conventional on-site practices.

As a reliable tool that further expands the possibilities of one-person layout, consider introducing simple surveying with LRTK. For details, see the [LRTK official site](https://www.lrtk.lefixea.com/).

FAQ

Q: How accurate is RTK surveying? Is RTK alone really sufficient? A: In favorable open environments, RTK-GNSS positioning can achieve about 2–3 cm (0.8–1.2 in) horizontal accuracy and about 3–5 cm (1.2–2.0 in) vertical accuracy. This level of precision is sufficient for many civil surveying and construction management tasks. However, cases have been reported where temporary errors of several tens of centimeters (several tens of in) occur in urban sites surrounded by high-rise buildings or in forests. For important reference points or structural centering, you can safely use RTK by double-checking with a total station, etc., after RTK measurement.

Q: If I have RTK, are total stations or levels no longer necessary? A: RTK is a very convenient surveying method, but it does not completely replace total stations (TS) or optical levels. Each has its own strengths: RTK allows one person to measure widely distributed points efficiently, whereas TS or levels are more stable for tasks requiring millimeter accuracy or optical straight-line extensions. It is ideal to use RTK and conventional instruments appropriately depending on site conditions. Maximize efficiency with RTK where possible and use TS or levels for the final fine adjustments to leverage the strengths of both.

Q: What is needed to use network RTK? A: To use network RTK (VRS methods, etc.), you need an RTK-compatible GNSS receiver and a communication environment to receive correction data via the Internet. Specifically, a mobile-enabled device at the rover (a receiver with a built-in SIM or smartphone tethering, etc.) and a subscription to a service that provides GNSS correction data are required. In Japan, in addition to paid correction services by private providers, free services using the Geospatial Information Authority’s reference station data (e.g., network reference points via Ntrip) are also available. If you can receive such correction information, you can obtain centimeter-level positioning in real time without installing your own base station. However, network RTK cannot be used at sites outside mobile communication coverage; in that case, you must either set up a base station on site to transmit correction information via radio, or switch to PPK surveying, which performs positioning calculations later.

Q: I’m uneasy about introducing RTK surveying for the first time. Will I be able to use it? A: Recent RTK equipment and software are designed with the user in mind, and basic operations are not difficult. Systems like LRTK allow surveying simply by following guides in a smartphone app, so they are easy to handle even with limited expertise. Still, to maximize positioning accuracy, it is desirable to understand correct equipment setup and satellite reception tips. Start by practicing in open areas, and gradually try more complex sites as you become comfortable. If you have questions, contacting the manufacturer’s support can help. With proper learning and experience, even beginners can master RTK staking layout in a short time.

Q: What is simple surveying with LRTK? A: LRTK is a solution that integrates an ultra-compact RTK-GNSS receiver that can be used with smart devices, a dedicated app, and cloud services. This enables anyone to perform centimeter-class surveying (simple surveying) easily without complicated settings or special equipment. For example, attaching an LRTK receiver to a smartphone and walking the site automatically acquires high-precision position data, which can be managed and shared instantly in the cloud. Staking positions and as-built measurements that used to be performed only by veteran surveyors can now be done accurately by less experienced personnel using LRTK’s intuitive AR navigation. In short, simple surveying with LRTK is a new layout method that realizes the high precision of RTK with more accessible equipment and operation, and its effects are already being demonstrated on many sites.