Fundamentals of RTK positioning and GPS/GNSS/QZSS positioning and application to high-precision system development

Understanding RTK Positioning

RTK, or Real-Time Kinematic, positioning is a GPS correction technology used to enhance the precision of position data derived from satellite-based navigation systems.

Typically, GPS alone can provide accuracy within about 10 meters.

However, with RTK positioning, you can achieve centimeter-level accuracy which is crucial for applications requiring high precision.

RTK technology works by utilizing a fixed ground-based reference station which broadcasts the difference between its known fixed position and the position calculated by the GPS satellites.

Mobile receivers, often called rovers, then use this corrective broadcast to fine-tune their own satellite-derived positions, resulting in a much higher accuracy level.

How RTK Positioning Works

To comprehend how RTK positioning works, it is essential to grasp the concept of carrier-phase measurements.

Unlike the traditional GPS approach that relies solely on measuring the time it takes for signals to travel from satellites to the receiver, RTK focuses on the carrier phase of the satellite signal.

The carrier phase is a more precise method of measurement and allows for the accuracy of centimeters instead of meters.

Furthermore, RTK systems use two main components: a reference station and a rover.

The reference station is a GPS receiver placed at a known location, gathering satellite data and determining errors in the signal.

These corrections are then sent to the rover – the moving GPS receiver – to adjust its raw satellite data for increased position precision.

This process occurs in real-time, thus allowing immediate applications such as in autonomous vehicles or aerial drones.

Exploring GPS/GNSS/QZSS Positioning

Globally, satellite navigation systems are collectively known as GNSS (Global Navigation Satellite System).

GPS (Global Positioning System) being one of the most well-known, is complemented by other systems like Russia’s GLONASS, Europe’s Galileo, and China’s BeiDou.

Japan’s QZSS (Quasi-Zenith Satellite System) is another satellite navigation system, focused on providing services to the Asia-Oceania region.

GPS and its counterparts serve one main purpose: determining precise geographical locations anywhere on Earth.

However, each system has unique regional advantages and other uses.

GNSS refers to systems that provide global coverage, while QZSS acts more as a GNSS augmentation service, primarily benefiting the Asia-Pacific region with enhanced accuracy and additional satellite visibility.

How Positioning is Achieved

Satellite navigation systems determine positions using signals sent from a network of satellites orbiting Earth.

Receivers on the ground, like those in smartphones or cars, capture these signals.

The receiver calculates its location using trilateration, which involves measuring the time it takes for signals to arrive from multiple satellites and using this data to triangulate a three-dimensional position.

Typically, signals from at least four satellites are needed to compute an accurate location providing latitude, longitude, and altitude.

In situations where satellite signals are weak or obstructed, such as dense urban environments or rugged terrain, regional systems like QZSS enhance overall system accuracy and availability.

High-Precision System Development

High-precision positioning systems are increasingly essential across various industries.

From agriculture and construction to telecommunications and transport, the need for real-time, pinpoint location data is growing.

RTK, GPS, GNSS, and QZSS are fundamental to developing high-precision systems that facilitate automation, accuracy, and reliability.

Applications of High-Precision Positioning

One major application of RTK and other high-precision positioning tools is precision agriculture.

Farmers utilize RTK systems to optimize field-level management, enabling them to reduce waste, increase crop yield, and enhance productivity.

Tractors and other machinery equipped with RTK receivers can autonomously navigate fields, apply fertilizers, or sow seeds with extreme precision.

In construction, surveying and machine control rely heavily on high-precision positioning.

Surveyors use RTK-GPS systems to ensure that constructions are accurately aligned and positioned per design specifications.

This precision translates to reduced rework, cost savings, and maintaining project timelines.

The transportation industry also benefits significantly from these technologies.

Autonomous and semi-autonomous vehicles rely on RTK and GNSS infrastructures to navigate accurately and safely, while smart traffic management systems utilize this data to optimize route plans and reduce congestion.

Challenges in High-Precision System Development

While the benefits of RTK, GPS, GNSS, and QZSS are clear, there are challenges when developing high-precision systems.

One major issue is signal obstruction caused by buildings, trees, or other environmental factors that can disrupt satellite communication.

This is critical, as even a momentary loss of signal can result in significant errors in position data.

Another challenge is the technical complexity involved in integrating these technologies, often requiring interoperability between several systems and accurate calibration to maintain consistency and reliability.

Moreover, data processing and storage with large datasets from positioning systems can strain computational resources.

Ensuring efficient and real-time data management is critical to maintaining speed and accuracy in high-precision applications.

Lastly, there is the need for continued development of infrastructure, particularly in urban canyons and remote regions, to support and maintain satellite visibility and communication.

Conclusion

RTK positioning, together with GPS, GNSS, and QZSS technologies, plays a crucial role in high-precision system development.

Understanding these technologies’ fundamental workings and their applications allows various industries to leverage the advantages of accurate location data.

While challenges exist, advancements in satellite technology and data processing continue to enhance the reliability and precision of these systems.

As a result, industries increasingly depend on such solutions to automate operations, increase efficiency, and drive innovation.