Overview of GNSS Stakeout Systems: High-Accuracy Surveying Anyone Can Do with Smartphone RTK

Table of Contents

• Challenges of traditional stakeout work

• Centimeter-level high-accuracy positioning with RTK (cm level accuracy (half-inch accuracy))

• High-accuracy surveying anyone can handle with smartphone integration

• Intuitive position guidance with AR technology

• Dramatic labor savings and operational efficiency improvements

• Real-time data sharing using the cloud

• Easy simple surveying to start with LRTK

• FAQ

Stakeout work, indispensable on construction and surveying sites, is a critical process that affects project quality and progress. Traditionally, this positioning work has required advanced plan-reading skills, many personnel, and significant time, creating a heavy burden on sites. Recently, precise position guidance using GNSS terminals has attracted attention as a way to solve these issues. By combining satellite positioning technology with digital tools, accurate stakeout is becoming possible for anyone, not just specialists.

This article first organizes the challenges of traditional stakeout methods and explains how GNSS (satellite positioning) technology can address them. It then looks in detail at the benefits that modern technologies bring to the field: RTK for centimeter-level positioning, easy operation via smartphone integration, intuitive guidance using AR (augmented reality), and cloud-based data sharing. At the end of the article, we introduce a simple surveying system that embodies these technologies, called LRTK, and propose a new stakeout approach that is easy for anyone to adopt.

Challenges of traditional stakeout work

Stakeout is the process of accurately marking on-site the positions and reference lines shown on design drawings in building and civil engineering works. Traditionally, this work has been carried out using tools such as chalk lines, chalk, and tape measures, along with surveying instruments like laser stakeout devices and total stations. For example, to lay out a building wall position or equipment centerlines, workers measure dimensions based on reference centerlines or string lines and mark the floor or ground. Accurate positioning requires proficiency in reading drawings and measurement, and small measurement errors can lead to later construction mistakes, so this has been a craftsman-like process requiring high skill.

Because stakeout is required at every stage from foundation work to finishing and equipment installation, its accuracy and efficiency directly affect the overall quality and schedule of the project. However, traditional stakeout methods have several issues.

• Labor and time burden: Surveying and stakeout are typically performed by teams of two or more people—one operates the surveying instrument or stakeout device while the other marks. Setting up and moving large, heavy equipment is laborious, and marking many points over a wide site can take an entire day. Because stakeout is performed at each stage, the total man-hours and labor required across a project can be enormous.

• Dependence on skilled workers: Stakeout requires the ability to read drawings and perform precise measurements, so projects often rely heavily on specific veteran technicians. If such a person is absent, other tasks may be put on hold waiting for stakeout, posing a risk of schedule delays. In recent years, the aging of skilled tradespeople and a shortage of young workers have made securing personnel with stakeout expertise a challenge.

• Accuracy control and safety issues: Manual stakeout inevitably carries the risk of dimensional errors and positional shifts due to human error. Especially in situations requiring millimeter-level accuracy, such as setting foundation positions or pile driving, manual surveying has limits. When carrying out stakeout in areas where heavy machinery is operating, ensuring worker safety also requires careful attention.

Centimeter-level high-accuracy positioning with RTK (cm level accuracy (half-inch accuracy))

A GNSS terminal is a device that receives signals from positioning satellites such as GPS to determine its own position. Smartphones also have GPS functionality, but standalone positioning accuracy is on the order of several meters, which is insufficient for construction stakeout. However, by using RTK (real-time kinematic) positioning, positioning errors can be reduced to within a few centimeters.

RTK positioning receives correction information in real time from a reference station (base station) set up on site or from reference station data delivered via the Internet, and applies these corrections to the rover GNSS positioning results. This mechanism cancels out slight deviations and error factors in satellite signals, enabling planar positioning accuracy of about ±1-2 cm (±0.4-0.8 in) and vertical accuracy of several centimeters (several inches). This level of precision, once achievable only with expensive surveying equipment, is now available with small GNSS receivers and a communications environment.

In Japan, infrastructure supporting RTK—such as the Geospatial Information Authority’s network of continuously operating reference stations and the quasi-zenith satellite system “Michibiki,” which provides centimeter-class positioning augmentation services (CLAS) (cm level accuracy (half-inch accuracy))—has been developed. This allows compatible GNSS terminals to acquire high-precision correction information directly from satellites even at sites in mountain areas or outside cellular coverage.

Using RTK-capable GNSS equipment for stakeout allows you to specify coordinate values from design drawings (for example, intersections of building centerlines) as targets on site. The device continuously measures its position at centimeter accuracy and displays the distance and direction to the specified coordinates in real time. Thus, workers can be guided directly to the positions shown on the design drawings.

High-accuracy surveying anyone can handle with smartphone integration

Many recent GNSS surveying devices can be used in conjunction with smartphones and tablets. By installing a dedicated app on a smartphone and attaching a compact GNSS receiver, a familiar smartphone instantly becomes a high-precision surveying tool. In the past, dedicated survey controllers and complicated initial setup were required, but now positioning can be started with just a few taps on the smartphone screen, making operation dramatically easier.

Smartphone integration offers the major advantage of an intuitive user interface that makes the tool easy for anyone to use. If you import drawing data or a coordinate list into the app, you can guide to target positions without difficult calculations or specialized knowledge. The app visually displays the current position and the direction and distance to the target, so staff with limited surveying experience can perform high-accuracy stakeout after a short amount of training.

For example, a basic workflow using a GNSS stakeout system is as follows.

• Preload design drawings and stakeout point coordinate values into the dedicated app.

• Connect the GNSS receiver to the smartphone and put it into a state capable of high-accuracy positioning (connect to a reference station service or start receiving CLAS signals as needed).

• Select the point or line you want to stake out in the app; the app then displays the bearing and distance from your current position to that target.

• Follow the smartphone screen guidance (arrows or AR display) and move to the specified position.

• Once at the exact position, mark the ground or structure to complete the stakeout.

In this way, automatic calculations and visual guidance have made surveying work that used to rely on specialists much more accessible.

Intuitive position guidance with AR technology

The combination of GNSS terminals and smartphone apps also enables position guidance using AR (augmented reality) technology. AR overlays digital information on camera imagery from a smartphone or tablet—examples familiar to many are games like Pokémon GO or AR navigation features in map apps. On construction sites, AR can display instructions such as “mark here” directly on real-world imagery.

For instance, when you point a smartphone camera at the site, reference lines and stakeout points from the design drawing can be overlaid as virtual lines and markers on the live view. Workers can simply follow the on-screen directions to mark the correct spot without measuring from a reference or calculating positions.

AR can also make normally invisible information intuitive on site, such as the completed design image or the locations of underground utilities. Projecting a 3D design model onto the site and sharing it among stakeholders reduces misunderstandings and helps smooth communication. Because AR’s visual guidance can be understood intuitively by non-experts, it significantly lowers the barrier to performing stakeout work.

Dramatic labor savings and operational efficiency improvements

GNSS-enabled stakeout contributes greatly to labor reduction on site. Surveying and stakeout that used to require a two-person team can be completed by a single worker, significantly reducing staffing needs. In the construction industry, where labor shortages are severe, being able to accomplish more work with fewer people is highly beneficial. In practice, even sites without resident surveying specialists can have site supervisors or engineers perform high-accuracy positioning themselves, eliminating wasted downtime caused by waiting for stakeout.

Digital technologies also dramatically improve operational efficiency. Shortening measurement times and improving accuracy reduce rework, contributing to overall schedule compression. Accurate stakeout done right the first time prevents construction mistakes in subsequent stages, directly improving project productivity and quality.

Real-time data sharing using the cloud

GNSS terminals and smartphone apps also integrate with cloud services, making data sharing between site and office much easier. Positioning data, photos, and notes captured on site can be uploaded to the cloud from the app with a single tap. Survey points and record information are immediately reflected in cloud maps and the project database, enabling office staff to grasp the latest situation in real time.

Conversely, if design changes or additional instructions occur, they can be shared instantly with the site via the cloud, reducing time lag between office and field and speeding decision-making. Because all surveying data are stored in the cloud, it is also useful later for verification or report preparation. Using the cloud connects site and office seamlessly and contributes to improved efficiency and information management for construction projects.

Easy simple surveying with LRTK

As a concrete example of the RTK positioning, smartphone, AR, and cloud solution described above, a GNSS positioning system gaining attention recently is called LRTK. LRTK consists of an ultra-compact RTK-GNSS receiver and a smartphone app; attaching this receiver to your phone allows a palm-sized device to achieve centimeter-level positioning (cm level accuracy (half-inch accuracy)).

The dedicated app lets you intuitively operate a variety of functions—coordinate measurement, stakeout guidance, point cloud measurement, and more—enabling work that leverages high-accuracy positioning with a level of ease unimaginable with traditional surveying equipment. Introducing the LRTK series can dramatically improve surveying accuracy and operational efficiency on construction and civil engineering sites. It is a solution compatible with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative and strongly supports DX (digital transformation) on construction sites.

Despite employing advanced technology, LRTK’s simple configuration makes it easy for anyone to use. All you need is a smartphone; the receiver has a built-in battery and antenna and supports receiving correction data. Install the dedicated app and you can start high-accuracy positioning on site without complicated setup, so even first-time users can quickly get up to speed. LRTK relieves the human burden and accuracy concerns in stakeout work and leads to productivity improvements. For more details on LRTK, please also see the [LRTK official site](https://www.lrtk.lefixea.com/).

FAQ

Q: What preparations and equipment are needed to use a GNSS stakeout system? A: Basically, you can start with an RTK-capable GNSS receiver and a smartphone (or tablet). The GNSS receiver transmits positioning data to the smartphone’s dedicated app, which displays coordinates and provides guidance. High-accuracy positioning requires correction information, so connect via the Internet to regional reference station data or use a device capable of receiving the CLAS signal from Japan’s quasi-zenith “Michibiki” to achieve centimeter-level positioning. Initial setup is relatively simple; follow the app’s guidance to begin positioning.

Q: How accurate is stakeout with RTK-GNSS? Is it really usable for construction? A: Using RTK for GNSS stakeout can achieve planar accuracy within a few centimeters and vertical accuracy on the order of a few centimeters. This level of accuracy is sufficient for typical building and civil engineering positioning tasks and is used in practical applications such as foundation positioning and earthworks. However, accuracy depends on satellite reception and the surrounding environment, so basic precautions—using open sky conditions and avoiding proximity to metal structures that can affect satellite reception—are necessary. With proper operation, GNSS can provide stakeout accuracy comparable to that of a total station.

Q: Can people unfamiliar with equipment operate it? Is specialized knowledge required? A: Yes—the GNSS stakeout system is designed to be easy to operate even for those unfamiliar with machinery or surveying. The app clearly displays the current location and target points, and following the instructions will guide you to the target position. If you have coordinate data from drawings, the app performs the calculations and guidance automatically, so advanced surveying knowledge is not required. After a brief introduction to basic operations, anyone accustomed to smartphones can learn to use the system in a short time.

Q: Is high-accuracy GNSS positioning possible in mountainous areas with no cellular coverage? A: High-accuracy positioning is possible even at sites without Internet connection if conditions are met. For example, receivers compatible with Japan’s CLAS from the “Michibiki” quasi-zenith satellites can receive correction data directly from satellites even outside cellular coverage. Another option is to set up and operate a mobile base station (local reference station). However, in deep mountain areas or heavily forested environments, satellite signals may not reach the receiver, so consider combining other methods such as drone surveying or terrestrial laser scanning in those cases.

Q: Can GNSS cover all stakeout needs? Are traditional surveying instruments no longer needed? A: GNSS positioning is powerful when rapidly setting many points outdoors over wide areas or when positioning based on design coordinates. However, GNSS cannot be used in indoor work, tunnels, or dense high-rise areas where satellite reception is impossible; in such cases, traditional instruments like total stations and levels remain essential. Therefore, it is necessary to use the appropriate method depending on site conditions. Nevertheless, for general outdoor stakeout tasks, GNSS stakeout systems can cover the majority of needs, reducing situations that require traditional instruments. Combining GNSS with conventional techniques further enhances on-site efficiency and flexibility.