RTK Increases the Precision of GNSS and GPS

By Amy Goetzman | July 09, 2024

GNSS and GPS modules are smaller than ever, enabling them to be designed into moving assets, track individual people or animals, and identify precise locations. Yet these systems require coordination with real-time kinematic (RTK) corrections and other technologies to achieve centimeter-level precision.

GPS (Global Positioning System) was the first satellite navigation system to be developed and deployed, and it laid the foundation for the broader concept of GNSS (Global Navigation Satellite System), which includes multiple satellite navigation systems from various countries. Both systems have been integrated into a multitude of devices across different sectors since the 1990s, adding navigation and tracking functionality to smartphones, computers and tablets, smartwatches, vehicles, aircraft, and many other devices. Our world is increasingly tethered to the satellites that circle it.

Today’s navigation technologies are more powerful than ever. Advances in signal processing techniques have improved the accuracy of GNSS/GPS receivers. The miniaturization trends that have impacted all electronic devices have made these modules ever smaller, enabling them to be applied to miniaturized devices, opening up new engineering possibilities. Today, navigation technologies assist autonomous technologies, farming operations, logistics, surveying, and emergency services, and are a critical part of many connected systems.

Würth Elektronik’s Elara and Erinome product families

Würth Elektronik’s Elara and Erinome product families of GNSS modules are some of the smallest GNSS modules on the market and come with and without an integrated antenna. For sophisticated navigation tasks, the Erinome series uses all four global navigation satellite systems at top speed: GPS, GLONASS, Galileo, and BeiDou.

But precision is still an issue: Würth Elektronik’s GNSS modules, for example, tap into multiple satellite systems to achieve a localization accuracy within 1.5 m during operation. That’s enough to navigate to an address, but for high-precision applications such as autonomous vehicles, precision farming, and surveying, which need centimeter-level precision, it doesn’t make the mark. GNSS still lacks the accuracy needed for these types of applications. That’s where real-time kinematic (RTK) corrections technology comes in. RTK helps GNSS pinpoint locations. RTK taps into thousands of off-base stations to measure the common sources of GNSS error to provide measurements that are 100 times more accurate than GNSS measurements. With RTK, GNSS can pinpoint locations or objects within a centimeter or two. That enables farmers to precisely map every object or condition in their fields in order to navigate hazards, apply chemicals, or monitor areas with variations in conditions. Surveyors can verify the locations of underground utilities before digging. Drones can pinpoint an object for mapping and photography. RTK is the most precise option for GNSS error corrections.

GNSS-L125-TNC Antennas from iConnexion achieve pinpoint accuracy with redundancy in positioning, which mitigates errors caused by multipath.

Connectors for GNSS

Connectors play a crucial role in integrating GNSS and GPS modules with other components and systems in devices. They facilitate the connection of GNSS modules to antennas, power sources, data interfaces, and other peripheral devices. Antenna connectors, such as SMA, MCX, and MMCX, make a secure connection between the GNSS module and the antenna, critical for receiving satellite signals. Connectors enable the transfer of data between the GNSS module and other components or systems and help provide a secure power supply. Recent developments in these product categories center on miniaturization, reliability, and versatility. Innovations include additional ruggedization for harsh environment use and low-loss connectors for better signal integrity. A recent category addition, U.FL (Ultra Miniature Coaxial) and MHF Connectors, are ultra-small RF connectors that have become popular choices for connecting antennas to GNSS modules in compact devices like smartphones, wearables, and IoT sensors.

The MHF1 connector from I-PEX is a locking micro RF connector with a wireless module that allows for installation space with mechanical retention. “One of the unintentional effects of size reduction is a less robust mechanical retention between mated pairs of connectors. A common, and often voiced, complaint is the signal loss of micro-RF connectors due to mechanical disengagement, which is often referred to as ‘pop-up’ or ‘pop-off,’” said the company. To help solve this issue without relying on epoxy, tie downs, or other methods, I-PEX has designed a locking solution

Recent GNSS advancements have significantly improved accuracy, reliability, and integration with other systems. Multi-frequency and multi-constellation receivers enhance precision and availability, while advanced correction services like PPP and Network RTK provide centimeter-level accuracy. Future development goals are focused on improving security with anti-jamming and anti-spoofing, integration with IMUs and other sensors, as well as the development of software-defined receivers.

The XPLR-HPG-1 Explorer kit for developing high-precision GNSS applications from u-blox is now available at Mouser Electronics. The kit provides a flexible, modular, and accurate platform for prototyping positioning applications, like robotics or connected health. The modularity provides endless possibilities for engineers to explore and build cutting-edge solutions.

As connected technologies continue to evolve, applications in autonomous systems proliferate, and miniaturization and low-power designs make GNSS technology more accessible for portable and IoT devices, this powerful technology will become an essential part of connected systems. Connector suppliers are responding with refined new options for both GNSS modules and the connectors that integrate them.

To learn more about the companies mentioned in this article, visit the Preferred Supplier pages for iConnexion, I-PEX, Mouser Electronics, and Würth Elektronik.

Like this article? Check out our other RF and Coax, and Antennas articles, our Sensors & Antennas Market Page, and our 2024 Article Archives

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Amy Goetzman
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