Evolution of GNSS Positioning Systems and RTK Accuracy Improvement

The major GNSS positioning satellites currently in operation include the United States’ GPS, Russia’s GLONASS, Europe’s Galileo, and Japan’s Quasi-Zenith Satellite System “Michibiki.” Including China’s BeiDou system, there are now over 120 satellites operating globally.

Multi-GNSS-compatible receivers can simultaneously receive signals from multiple satellite systems, significantly increasing the number of satellites available for positioning. As a result, improved satellite geometry enhances positioning accuracy and makes it easier to maintain the required number of satellites even in challenging environments, such as urban areas or mountainous regions where some satellites may be obstructed.

In RTK positioning in particular, the adoption of Multi-GNSS significantly reduces the time required for initialization (integer ambiguity resolution), allowing users to obtain a fixed solution more quickly. In fact, it has been reported that receivers supporting a greater number of satellites and frequencies tend to offer improved positioning availability, accuracy, and environmental robustness. Additionally, Japan’s Quasi-Zenith Satellite System “Michibiki” provides signals through the Centimeter-Level Augmentation Service (CLAS), enabling centimeter-level positioning with a standalone receiver, further contributing to the future advancement of RTK accuracy.

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Industry Impact of Ultra-High-Precision RTK

The improvement in satellite positioning accuracy through Multi-GNSS support and the advancement of ultra-high-precision RTK are transforming work practices in the construction and surveying sectors. For example, in construction site surveying, tasks such as as-built measurements and installations can now be performed more efficiently with fewer control points. Machine guidance systems for heavy equipment are also becoming more precise, accelerating automation and reducing the need for manual labor. The concept of “one-person surveying,” where a single surveyor carries a GNSS receiver and completes field measurements independently, is becoming more common, leading to greater operational efficiency. In infrastructure management, RTK is being applied to tasks such as structural displacement monitoring and high-precision recording of underground utilities. In precision agriculture, centimeter-level positioning is essential for automated tractor operation and accurate control of seeding processes.

RTK-GNSS is also being increasingly adopted as a key component for high-precision self-positioning in autonomous vehicles and drones. The communications sector is further supporting this trend. In Japan, major telecom carriers have begun offering high-precision positioning services integrated with 5G networks. With the rapid transmission of real-time correction data and the shared use of network-based reference stations, the application of RTK is expected to expand even further—from urban areas to mountainous regions.

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Integration of LRTK with Next-Generation RTK Technology

Amid the trend toward ultra-high-precision RTK enabled by Multi-GNSS, Lefixea’s LRTK series has emerged as a key solution. LRTK is a compact RTK-GNSS receiver device that leverages signals from multiple GNSS systems—including GPS, GLONASS, Galileo, and Japan’s Quasi-Zenith Satellite System “Michibiki” (CLAS-compatible)—to enable seamless centimeter-level positioning in coordination with smartphones and tablets.

For example, the LRTK Phone is an all-in-one antenna-integrated receiver that attaches to the back of a smartphone. Through a dedicated app, it can receive network-based RTK corrections (via the Ntrip protocol) and CLAS signals from Japan’s Quasi-Zenith Satellite System “Michibiki,” enabling users to instantly acquire high-precision coordinates outdoors. A key feature of the LRTK series is its integration with a cloud service called LRTK Cloud. Positioning data, photos, and point clouds collected in the field can be uploaded directly to the cloud, where they are centrally managed using a unified global coordinate system.

On the cloud, positioning results and 3D models can be instantly shared with stakeholders, enabling remote offices to monitor progress in real time and provide instructions as needed.

LRTK Cloud is evolving into a next-generation platform that supports smart construction, with upcoming features including integration with the Ministry of Land, Infrastructure, Transport and Tourism’s 3D city model data “PLATEAU” and augmented reality (AR) visualization capabilities.

In this way, LRTK integrates high-precision Multi-GNSS positioning technology with IoT and cloud services, creating an environment where even non-specialists can easily perform centimeter-level positioning using smart devices. As a result, it is becoming a key device driving digital transformation (DX) in the construction industry.

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The Future of RTK Positioning and GNSS Technology

Satellite positioning technology is expected to continue evolving in the future. One of the key advancements is the fusion of next-generation positioning methods, such as PPP-RTK. PPP (Precise Point Positioning) is a technology that uses global, precise satellite orbit and clock error information to achieve centimeter-level accuracy at a single point. However, it has a challenge in terms of long initialization times. To address this, PPP-RTK combines local error correction data from reference station networks around the world, enabling faster initialization comparable to RTK.

For example, the CLAS (Centimeter-Level Augmentation Service) provided by Japan's Quasi-Zenith Satellite System "Michibiki" (in geostationary orbit) is based on the concept of PPP-RTK. This service enables high-precision positioning even in areas without ground infrastructure, as it only requires receiving augmentation signals from satellites.

In the future, high-precision services such as the HAS (High Accuracy Service) from Europe’s Galileo and augmentation signals from China’s BeiDou will enhance satellite-based correction delivery worldwide, making global, uniform centimeter-level positioning a reality. Additionally, new industries utilizing GNSS, such as autonomous mobile robots (AMR), drones, and location-based services in smart cities, are expanding. The continued reduction in the cost and size of GNSS chips has also led to the integration of multi-frequency GNSS in smartphones. With the "100-satellite era" providing a favorable GNSS environment, there is growing anticipation that this will enable seamless indoor and outdoor positioning and the development of more advanced location-based services, unlocking new possibilities.