Improving Construction Site Efficiency with LRTK Implementation

In recent years, the construction industry has seen accelerated digital transformation (DX), with growing focus on efficiency gains through high-precision GNSS positioning technology.

Among these, Real-Time Kinematic (RTK) positioning is revolutionizing surveying and construction management sites by delivering centimeter-level accuracy and real-time capabilities unattainable with conventional methods.

This article explains how implementing the high-precision RTK solution LRTK can enhance construction site efficiency, illustrated with concrete examples.

What is RTK? Why is it needed on construction sites?

RTK (Real-Time Kinematic) is a type of high-precision positioning technology using GNSS (Global Navigation Satellite System). It achieves centimeter-level accuracy by simultaneously performing satellite positioning at a base station (reference point) and a rover station, then sending real-time position error correction data from the base station to the rover.

While conventional standalone GPS positioning resulted in positional errors of several meters, RTK reduces this error to just a few centimeters. For example, in Japan's public surveying, network-based RTK surveying—which obtains correction data from an electronic reference point network—enables real-time centimeter-level positioning on-site without setting up a base station.

The primary reasons RTK is demanded on construction sites are precision and immediacy. Civil engineering projects require high accuracy for structural positioning and as-built management; significant errors directly lead to rework and quality degradation. RTK enables the acquisition of precise coordinates on-site, allowing design and construction processes to proceed smoothly after surveying.

Furthermore, amid growing shortages of skilled surveyors, RTK enables rapid surveying with fewer personnel, reducing site burdens and promoting labor savings. Recently, RTK-GNSS has also been utilized for machine guidance of heavy equipment as part of ICT construction (information-based construction). Initiatives are expanding where receivers are mounted on bulldozers and shovels to perform automated precision construction. Thus, RTK has become an indispensable foundational technology for advancing construction DX.

Benefits of LRTK Implementation (Reduced Work Time, Cost Savings, Improved Accuracy)

LRTK is our company's high-precision RTK positioning solution. Implementing LRTK on construction sites delivers numerous benefits, including:

Reduced Work Time

Implementing RTK positioning significantly shortens surveying time. By receiving correction data in real time and enabling rapid positioning, tasks that previously involved a time lag—such as surveying on-site followed by calculations back at the office—can now be completed on the spot. For example, using network RTK eliminates the need to set up a base station, allowing surveying with just a single GNSS receiver.

A construction company in Osaka reported that RTK implementation “eliminated the need for base station setup, allowing surveys previously requiring multiple total station trips to be completed in a single pass.” Thus, LRTK dramatically reduces site preparation and observation frequency, significantly cutting time spent on surveying and construction management.

Cost Reduction

Reduced working hours and improved personnel efficiency directly translate to cost savings. RTK enables labor-saving surveying, allowing tasks like control point surveying and stakeout, previously requiring a two-person team, to be handled by a single person. The reduction in labor costs and days required is significant. Bringing outsourced surveying work in-house also offers potential cost savings. In fact, one small-to-medium general contractor saw improved on-site responsiveness while reducing outsourcing costs after introducing RTK equipment to perform construction surveying in-house. Furthermore, while the initial investment for the latest RTK terminals like LRTK is higher, their operational running costs are low, offering substantial long-term cost benefits. Operating your own base station requires communication line fees, but using a network-based RTK service allows sharing across multiple sites, reducing equipment rental and relocation costs.

Improved Accuracy

The greatest benefit of implementing RTK is the dramatic improvement in positioning accuracy. LRTK achieves horizontal accuracy of approximately 2-3 cm and vertical accuracy of about 3-4 cm. This represents a hundredfold improvement over standalone positioning, reaching a level suitable for millimeter-level applications like structural installation and as-built measurement. The ability to acquire high-precision data in real time also enhances the accuracy of subsequent design and construction planning, preventing waste from rework and corrections.

For example, combining RTK with drone photogrammetry allows for reduced control points while maintaining accuracy, enabling the acquisition of far more precise terrain data in a shorter time than conventional methods. In this way, LRTK dramatically elevates the quality of data delivered to the field, enabling surveying and construction that is “not only fast but also reliable.”

Practical LRTK Applications on Construction Sites

LRTK and RTK technologies are increasingly utilized across various civil engineering and construction scenarios. Below are several key application examples.

• Example: Terrain surveying at a construction site using a GNSS base station (foreground) and an RTK drone (background)

Application in Construction Surveying (Topographic Surveying)

Traditionally, at site preparation areas or for structural positioning, surveyors used total stations to measure angles and distances and set out stakes. After introducing RTK, a GNSS receiver is set up to instantly acquire coordinates for each point, enabling on-site pile driving or marking. Since one person can survey multiple points, initial surveys for large sites can be completed in a short time.

Application in UAV Photogrammetry

Mounting an RTK receiver on a drone for aerial photography enables real-time correction of GPS log errors, reducing post-processing work for aligning control points. High-precision terrain models can be created without human access, even in vast earthwork sites or steep mountainous areas. In practice, maps and point cloud data generated from aerial photos captured by RTK-enabled drones offer significantly improved accuracy compared to conventional methods, aiding design and as-built management.

Heavy Equipment Machine Guidance

At large-scale sites like highway and dam construction, ICT construction machinery equipped with GNSS antennas on bulldozers and power shovels is increasingly common. By accurately determining the machine's position via RTK and automatically controlling blade or bucket height without relying on operator sightlines or stakes, it improves finish accuracy while streamlining operations. Another advantage is the ability to maintain stable quality during nighttime or inclement weather construction.

Infrastructure Maintenance

RTK is also utilized in maintenance and inspection tasks for railways and highways. For instance, in detecting track distortion or monitoring road subsidence, RTK-GNSS enables rapid acquisition of data from numerous measurement points. Traditionally, such work required operation during short overnight windows, but RTK is expanding maintenance windows and increasing measurement frequency (based on Ministry of Land, Infrastructure, Transport and Tourism verification tests). Additionally, in disaster recovery projects, RTK drones are sometimes deployed for 3D surveying of damaged areas, aiding in rapid situation assessment and recovery design.

In this way, LRTK contributes to streamlining and advancing operations across diverse scenarios—from surveying to construction and maintenance. The use of RTK is likely to expand into an increasingly wide range of field applications going forward.

Differences from Competitive Technologies (Conventional Methods vs. RTK)

Surveying and positioning using RTK differ significantly in procedures and requirements compared to conventional methods (surveying using total stations or levels, or standalone GNSS positioning). Furthermore, while conventional surveying was labor-intensive at sites with large elevation differences, RTK is efficient because it can measure positions even at points without line-of-sight, provided satellite signals reach them. However, RTK relies on GNSS signals, meaning positioning is impossible in locations with obstructed sky visibility. While RTK is not a universal solution, its immediacy and efficiency make it a technology capable of simplifying many field operations.

LRTK Implementation Process and Key Considerations

This section outlines the typical steps for implementing LRTK for field use and highlights essential points to consider.

Implementation Steps

• Developing the Implementation Plan First, identify the site's needs and determine which operations will utilize RTK. Consider the required accuracy, coverage area, and integration with existing surveying systems (e.g., how to connect with existing control points). Also decide whether to use a network-based solution or install your own base station.

• Select Equipment and Services Procure LRTK terminals (rover receivers) and base station equipment based on your application. If using network-based RTK, prepare VRS delivery services and SIM contracts. Our LRTK terminals are compact, lightweight, and feature built-in mobile communication capabilities. They can automatically acquire electronic reference point data acting as a base station, enabling immediate positioning on-site.

• Initial Setup and Trial Operation Configure the equipment and perform accuracy verification at known points and trial surveys. Verify the coordinate system (e.g., WGS/JGD2011) and positioning mode, and check for errors against existing drawings. For first-time RTK users, conducting test surveys in a small area is recommended, also serving as operational training.

• Field Implementation Start Begin surveying and construction using LRTK in actual projects. During positioning, constantly monitor satellite reception status and correction data reception. If abnormalities occur, immediately compensate using re-measurement or backup methods. Perform accuracy checks (check surveys) at known points before and after daily work to maintain system accuracy.

• Post-Implementation Evaluation and Expansion Evaluate the benefits gained (time savings and accuracy improvements) and share this knowledge internally. If the benefits are significant, expand the use to other sites. Aim to establish this as a company standard in the future to advance the digital transformation (DX) of positioning tasks. Also, check for software update information and new services provided by the manufacturer to continuously enhance the level of utilization.

Translated with DeepL.com (free version)

Precautions During Implementation

• Ensure Clear Skyline RTK-GNSS surveying fundamentally requires a wide, open sky above the antenna. In urban areas obscured by buildings or mountain valleys, satellites may not be sufficiently captured, leading to reduced accuracy or positioning failure. Take countermeasures as needed, such as shifting positioning points or temporarily supplementing with a total station.

• Communication Environment When using network-based RTK, a communication line is required on the mobile station side. Mobile communication may become unstable in mountainous areas or underground. Consider installing repeaters or having an offline backup plan (e.g., switching to post-processing PPK).

• Initial Costs Introducing RTK equipment involves a certain initial investment. However, as mentioned earlier, the cost is usually fully offset by reduced labor costs and increased productivity. Utilize public support programs, such as the Ministry of Land, Infrastructure, Transport and Tourism's (MLIT) i-Construction equipment subsidy, to minimize the cost burden.

• Accuracy Management It is essential to verify that the positioning results consistently meet the required accuracy. Conduct check surveys at known points daily and per site to verify that no abnormal errors occur. Additionally, cross-checking by partially verifying survey results using conventional methods is effective during the initial implementation phase.

By keeping the above points in mind, LRTK implementation will proceed smoothly, allowing its performance to be fully realized on-site.

If You're Considering LRTK Implementation

LRTK is a solution gaining traction across a wide range of sites, from small civil engineering firms to major general contractors. We've entered an era where high-precision positioning technology is accessible even to non-professionals, signaling a transformative period for construction sites.

If your company is considering “streamlining surveying” or “advancing DX,” we strongly encourage you to explore LRTK implementation. We offer free materials detailing LRTK products and real-world use cases. Feel free to request these free materials via the link below.

For specific implementation consultations or demo requests, please use our inquiry form.

Boost your site's productivity with automated, high-precision positioning technology. LRTK powerfully supports your first step forward.

Translated with DeepL.com (free version)