Over 70% of the Earth’s surface is oceans, seas, and other waterways. So it’s no surprise that there’s an enormous market for GNSS applications focused on marine and maritime use cases, from navigation to asset tracking:
- Vessel Navigation and Open Sea Routing
- Automatic Identification System (AIS) and Collision Avoidance
- Vessel Traffic Services (VTS) for Coastal Monitoring
- Dynamic Positioning for Offshore and Oil & Gas Platforms
- Port Operations, Docking, and Cargo Handling
- GNSS in Search and Rescue (SAR) Missions
- GNSS for Fisheries, Oceanography, and Marine Research
All of those applications have one thing in common: They require a high-quality antenna to maximize accuracy and availability. Here’s what to look for.
Navigating the GNSS Constellation Options
When choosing an antenna, one initial consideration is which GNSS system(s) it will use. The answer depends partly on where the application will be used. There are six GNSS systems, but only four of them provide global coverage:
- The U.S. GPS constellation consists of 31-plus satellites that ring the Earth.
- China’s BeiDou (BDS or Compass) started as a regional system but now provides full global coverage with 35 satellites.
- The European Space Agency’s Galileo became fully deployed globally in 2018 with 24 satellites launched, plus six spares.
- The Russian Federal Space Agency’s GLONASS is a global system with a focus on providing positioning in high latitudes.
The other two GNSS systems are focused on providing regional coverage:
- Japan’s Quasi-Zenith Satellite System (QZSS) serves eastern Asia-Oceania. It became fully operational in 2018 with four satellites.
- India’s IRNSS, or NavIC, is focused on India and surrounding areas. It became fully operational in 2018 with seven satellites.
If a maritime application requires a continuous, 100% reliable source of positioning and/or timing information, then it’s worth considering a GNSS module and antenna system that support multiple bands and multiple constellations. (For more information, see “Navigating the L1, L2 and L5 Band Options for GNSS.”)
Another consideration is the application’s latitude. If the GNSS devices are located above or travel above 55 degrees, GPS accuracy begins to suffer because its satellites rise only 45 degrees above the horizon. This limits visibility of its satellites. A module and antenna system that supports GLONASS and/or Galileo enables the application to take advantage of constellations whose orbits provide better coverage in higher latitudes. (For more information about how latitude affects GPS accuracy, see “GNSS/INS Simulations of High-Latitude Operations.”)
How to Maximize Accuracy, Resiliency, and Longevity
A multi-band antenna can provide three additional benefits, starting with future proofing. For example, an application might prove so successful that it make business sense to expand it beyond its initial geographic market, such as from the Atlantic to APAC. If the module and antenna can support the IRNSS and QZSS frequencies, then it’s faster, easier, and cheaper to expand the application’s market than if the device has to be re-engineered with a new antenna.
A second benefit is resiliency against jamming and spoofing. Hackers, rogue nation states, and other attackers are increasingly targeting both civilian and government GNSS applications. Each constellation has multiple signals, each operating at a different frequency, which can provide alternatives when the primary GNSS signals are jammed. (For more information, see “Get Out of a Jam: How GNSS Antennas Help Thwart Jamming Attacks.”)
Finally, a multi-band antenna can increase accuracy by enabling the module and application to take advantage of the L-Band, which is home to data services that augment GNSS signals to maximize granularity down to the centimeter level. Also known as precise point positioning (PPP), these L-Band services provide a low-cost alternative to real-time kinematic (RTK) correction services, making them a good fit for applications that require accuracy and affordability. The ability to support L-Band services is valuable for a growing variety of maritime applications, such as autonomous vehicles at ports that move shipping containers. (For more information, see “How to Leverage the L-Band to Balance Accuracy and Affordability for GNSS Applications” and “High Precision GNSS and RTK Positioning.”)
What Makes an Antenna “Marine Grade”
Whether it’s freshwater such as the Amazon and Lake Victoria or seawater such as the Pacific, marine environments are tough on delicate electronics. Hence the importance of choosing a GNSS antenna that’s designed to withstand everything for salt spray to seagulls.
One example is the Taoglas Neptune XAHP.30, a multi-band, multi-constellation ruggedized antenna. Its enclosure is IP67-rated, which means it’s designed to protect the antenna inside even when submerged up to 1 meter submersion for 30 minutes. (For a deeper dive, see “How IP and IK Ratings Measure Real-World Durability.”) The Neptune’s enclosure is domed, which prevents bird damage by making it uncomfortable to perch.
Both the enclosure and antenna are designed to operate in temperatures between -40C and +85C without any performance degradation. This range, along with multi-band, multi-constellation support, make the Neptune a particularly good fit for single-SKU GNSS solutions that will be sold worldwide.
GNSS has become a fundamental tool for modern mariners just like the sextant was for centuries. For more information about Taoglas antennas, mounts, cables, and engineering services for marine and maritime applications, visit https://www.taoglas.com/markets/aerospace-and-defense/naval-application.