Consistent support from positioning to stakeout? How to use LRTK Phone + Cloud

In construction sites, the task of "stakeout" that determines the position of structures according to design drawings is an indispensable process for construction managers and surveyors. However, stakeout requires high precision, and traditionally it demanded skill in operating surveying instruments and performing complex calculations. Are you spending extra time re-measuring and having multiple people check to place piles with no margin of error even of a few centimeters (a few in)?

To solve such on-site problems, a new tool that consistently supports the flow from positioning to stakeout has emerged. That is LRTK Phone + Cloud. By combining a smartphone with RTK (real-time kinematic) positioning technology and cloud services, surveying and layout tasks that used to require multiple devices and personnel can be greatly streamlined. This article explains practical ways to use LRTK Phone and the cloud at construction sites, covering achievable RTK positioning accuracy, the simplicity of smartphone operation, accurate stakeout work via AR guidance, and workflow improvements through cloud processing and real-time sharing.

The importance and challenges of stakeout at construction sites

"Stakeout" refers to the work of accurately indicating points on site with stakes or chalk lines based on pre-determined design coordinate positions. This process, which restores the centers of foundations or corners of structures shown on construction drawings to the field, is also called surveying or setting out, and plays a crucial role that affects construction quality. Even a slight misalignment can cause distortion of the entire structure or construction defects, so stakeout requires high precision at the millimeter and centimeter levels.

However, traditional stakeout work had many challenges. In typical methods, a total station (an optical surveying instrument) is first set up at a control point, and distance and direction to the desired point are calculated and measured. A skilled surveyor prepares a stakeout calculation sheet on site, aligns the instrument angles, and staff carry a prism to the indicated position to drive the stake—this sequence requires at least two people and a high level of expertise. Depending on site conditions, visibility can be poor or direct measurements may be blocked by obstacles, requiring detours and workaround measurements. Naturally, this increases work time, and it is common to be occupied with checking and redoing measurement points. With a shortage of experienced personnel these days, performing stakeout safely and efficiently has become a major on-site challenge.

Manual reading of angles and distances and performing calculations also carry the risk of human error. If a stake is placed at an incorrect location, rework in later stages can cause significant cost loss. Stakeout is a delicate task that demands both "carefulness" and "efficiency," and there has always been a call at sites to look for improvements.

Smartphones become surveying instruments: high-precision positioning realized with LRTK Phone

LRTK Phone is a compact high-precision GNSS receiver that attaches to a smartphone. For example, by simply snapping the dedicated device onto a terminal like an iPhone, the smartphone GPS—which normally has errors of several meters (several ft)—is instantly upgraded to centimeter-class accuracy. This is the power of positioning technology called RTK (real-time kinematic). RTK-GNSS corrects satellite positioning errors in real time using correction data from base stations, reducing positioning errors to within a few centimeters. LRTK Phone supports this RTK method and can receive network correction services and CLAS signals delivered from Japan’s Quasi-Zenith Satellite System "Michibiki," enabling position information with accuracy comparable to expensive surveying instruments.

A distinctive feature of this high-precision device is its portability and ease of use in the palm of your hand. Weighing only about 125g, it has a built-in battery, so it can be carried easily without mounting it on a surveying pole or tripod. On site, you can take it from your pocket, attach it to your smartphone, and start the dedicated app to begin positioning immediately. No complicated initial setup or cable connections are needed; once satellites are acquired, precise coordinates of the current location can be obtained instantly. The app automatically converts not only latitude, longitude, and height but also into various coordinate systems required for construction work such as plane rectangular coordinates and geoid heights, so on-site personnel don’t need to worry about difficult calculations.

The positioning information obtained with LRTK Phone combines an unprecedented level of accuracy and convenience compared to conventional methods. For example, by remaining stationary and averaging positioning over a period, precision confirmation at the millimeter level is even possible. Precision surveying that previously required heavy and expensive dedicated equipment can now be performed anytime with just a smartphone, dramatically speeding up on-site positioning tasks. From checking control points to point cloud measurement for as-built management, an era is approaching in which a smartphone functions as an all-purpose surveying instrument.

Easy smartphone operation makes anyone immediately effective

Another major benefit of LRTK Phone + Cloud is its ease of use. Traditionally, operating surveying equipment required specialized knowledge, and many tasks had to be entrusted to veteran surveyors. But an LRTK system based on a smartphone allows positioning and point setting through an intuitive app. You simply follow the map screen or camera view, so construction management staff without formal surveying training can quickly master it. From young workers to veterans, anyone can practice high-precision surveying with a smartphone-like interface, contributing to the entire team becoming immediately effective.

Furthermore, the simplicity of completing tasks on a smartphone enables one-person operation. For example, where placing stakes used to require two people working as a pair, LRTK allows one person to handle both positioning and guidance simultaneously. Carrying a smartphone in one hand while walking to the required points eliminates the need for preparation work like carrying and setting up heavy tripods. You can move nimbly in tight sites or on terrain with elevation differences to perform surveying and stakeout, responding flexibly. There is no need to "wait for the surveying team"—the on-site person can measure and confirm on the spot, speeding up decision-making.

In this way, smartphone operation with LRTK Phone transforms on-site work. It simplifies complex procedures and tasks that relied on expert skills, achieving both labor reduction and time savings. By leveraging the familiar smartphone platform, the benefits of the technology can permeate every corner of the job site.

Achieve precise stakeout with AR guidance

The LRTK app includes a coordinate navigation function that guides workers to the coordinates they set. If coordinates for stakeout points are pre-registered in the cloud, workers can simply follow the instructions on the smartphone screen on site to reach the target points. Since the direction and distance to the goal are displayed in real time, the effort of gradually zeroing in on the position by cross-referencing maps and numbers has been greatly reduced.

Moreover, LRTK strongly supports stakeout work using AR (augmented reality) technology. When viewing the smartphone screen through the camera, virtual "AR stakes" or markers are overlaid at the specified positions, visualizing those points in the real space. For example, projecting AR stakes on the ground corresponding to stake points or markings indicated in the design drawings makes it immediately obvious where to drive the stake. This turns what used to be manual fine-tuning of position by measuring distances—"is it around here?"—into fast and accurate work guided by intuitive visual information.

A major advantage of AR guidance is that points that are physically difficult to approach can still be positioned and confirmed. For instance, points on steep slopes or in restricted-access areas can be measured from a safe distance and displayed as markers in AR to understand positional relationships. When it is difficult to drive a stake into hard concrete, AR stakes provide position markers without damaging the surface. Furthermore, if design data (such as BIM/CIM 3D models) are uploaded to the LRTK cloud, those models can be displayed in AR on site and overlaid with the current terrain or structures for verification. For example, projecting a planned retaining wall or fill model onto the actual terrain in AR allows preliminary checks to ensure stakeout positions match the design and that there are no conflicts with surrounding elements.

Because LRTK’s AR functions are based on stable position information from high-precision GNSS, there is no worry that projected virtual objects will shift when a worker moves. They are always displayed based on correct coordinates, making AR a powerful communication tool on site. By viewing the AR screen together with a client or construction team and saying, "This is where the structure will be installed," explanations of stakeout results and construction planning discussions proceed smoothly. AR guidance prevents stakeout mistakes in advance and streamlines confirmation and approval processes.

Data sharing and efficiency through cloud integration

A key strength of the LRTK system is real-time data sharing that links the field and the cloud. Positioning data collected on site can be uploaded to the LRTK cloud (web platform) with one tap. Uploaded points and track information are immediately plotted on the cloud map, and names, timestamps, coordinates, and notes for measurement points can be checked in a browser. Colleagues in the office or clients can access the web page without installing dedicated software to grasp site progress and results in real time. The cloud also has analysis functions, such as calculating the distance between two measured points, enabling immediate additional checks based on field data.

There are also robust easy sharing features. For example, to share data with a subcontractor or another department, simply select the target data on the LRTK cloud and press the "Share" button to issue a viewing URL. Passwords and expiration dates can be set as needed. Sending the issued URL to a recipient allows them to access the LRTK cloud web interface without logging in and view the shared data. Point clouds and photos can be viewed in 2D/3D in the browser, making it easy to measure distances, areas, and volumes or perform checks by overlaying design drawings. If necessary, data can be downloaded in CSV or predefined formats and imported into your company’s CAD software or reports.

With this cloud integration, the field, the office, and all stakeholders can always share the latest information. There is no longer a need to wait for someone to return to the office with survey data on a USB or to transcribe handwritten notes before emailing them. If points established during stakeout are saved to the cloud with photos, they become persuasive evidence for later inspections or handovers. All data are accumulated and versioned in the cloud, making it easy to look back and see "which point was placed where." Such digital linkage directly contributes to the efficiency and quality improvement of construction management, including stakeout.

On-site use case of LRTK: how stakeout work changes

What exactly changes on site once LRTK Phone + Cloud is introduced? Let’s look at one day on a construction site as an example to see the effects.

In the morning, construction manager A arrived on site, attached the LRTK Phone to his smartphone, and launched the dedicated app. He first measured known control points with LRTK to confirm the site’s coordinate system. Where traditionally a total station would be set up and traverse surveying performed, LRTK completed the control alignment in minutes.

Next, he loaded the day’s scheduled stakeout points (chalk-out locations and pile positions) from the cloud into the app. A selected the first point from the app screen and started coordinate navigation. Following the arrow and distance display on the smartphone, he soon reached the target location. When he raised the camera, a virtual AR stake appeared on the ground at the design-specified position. After rechecking the position and orientation, A marked the ground with a marking spray. That completed positioning of one point. He took a site photo with his smartphone and uploaded it to the cloud via the app to share the completion of that point with the team.

During the morning, A continued to set out stakeout points around the site following the same procedure. Working alone, he maintained centimeter-level accuracy for all points, and every point fell in the correct position according to the drawings. Points in low-visibility areas were accurately located using AR stakes without issue. A supervisor in the office could monitor A’s progress in real time on the cloud map and immediately advise, "The next point is beyond the safety fence, so be careful." Since photos and notes for each point are automatically saved on the LRTK cloud, A had no worry of missing records while concentrating on work.

In the afternoon, after all scheduled stakeout points were set, A used the day’s collected point cloud data to perform an as-built verification. Walking the site with his smartphone, he overlaid the LRTK-acquired point cloud with the design model in the cloud and checked the results. He confirmed on site that positions and elevations of important structures matched the design values and reported to the team that no additional corrections were needed.

What normally would have taken a surveying team and multiple people a full day was efficiently completed by A alone thanks to LRTK. At the end of the day, all the day’s result data were already assembled in the cloud, so A did not have to rush to prepare reports after returning to the office. Supervisors and clients had already confirmed the results, eliminating the need for separate explanations of survey outcomes later.

By incorporating LRTK Phone + Cloud on site, stakeout workflows change dramatically. One person can handle the workload of several, while simultaneously improving quality and recordkeeping—realizing an ideal construction management cycle.

Conclusion: stakeout surveying at sites changes—toward a new standard

Traditional stakeout and surveying work that relied on experience and intuition is about to be transformed by LRTK Phone + Cloud. The reliability of high-precision RTK positioning, smartphone-based ease of use, intuitive AR guidance, and seamless information sharing via the cloud—combining these leads to dramatic improvements in productivity and quality control on construction sites. Complicated stakeout work can now be completed with a single smartphone, creating a new standard where anyone can accurately set out positions.

Why not try applying these latest technologies at your site? Introducing LRTK gives you a powerful tool that handles everything from positioning to stakeout. LRTK Phone + Cloud is a solid solution for challenges such as labor shortages and limited work time. If you are a construction manager or surveying technician struggling with ensuring accuracy and efficiency in stakeout surveying, consider testing this new approach on your site.

The environment LRTK enables—where "each person can be a surveyor"—symbolizes the DX (digital transformation) of the construction industry to come. With LRTK Phone + Cloud, which fuses advanced positioning technology and field know-how, elevate stakeout work to the next level and carve out the future of your sites.