Electronic Positioning, Navigation, and Timing (PNT) solutions are the norm for modern mariners, with several GNSS options available, and their accuracy is enhanced by augmenting the GNSS signal, AMSA notes in a new guide, referring to the trends expected to affect its provision of navigation services.
In the maritime sector ground-based augmentation systems (GBAS) are increasingly making way for satellite solutions to increase GNSS position accuracy.
GNSS signals are vulnerable to disruptions such as jamming and spoofing, where signals are deliberately blocked or falsified. The growing frequency of such incidents underscores the need for enhanced protective measures, the development of alternative navigation solutions and a global consensus on a coordinated approach to resilient PNT for the maritime sector.
PNT also underpins a variety of safety-related maritime services and is a key requirement for e-navigation. Achieving resilient PNT requires effective solutions for the synthesis of data from disparate PNT technologies.
• Multi constellation GNSS receivers
• SBAS for GNSS
• Radar absolute positioning (includes, e-RACON and enhanced radar positioning systems (ERPS),
radar conspicuity mapping, terrain mapping, and Simultaneous localization and mapping (SLAM))
• eLoran (enhanced Loran, a modernised version of Loran-C)
• Light detection and ranging (LiDAR)
• Inertial navigation systems (INS)
• Fusion techniques for PNT information
5 Trends that will affect positioning, navigation and timing services
- Multi-constellation GNSS has become the primary source of PNT information
- Augmented GNSS (either by ground-based or satellite means) will continue to play a vital role in the provision of high accuracy and integrityproven PNT information.
- The increasing availability of GNSS and other sources of electronic PNT information (e.g. e-racons) are contributing to resilient PNT on board ships.
- Development of a variety of technologies to integrate satellite, terrestrial and shipsensed PNT solutions on board ships
- Growing consensus that a national PNT resilience plan is required to mitigate degradation of satellite based PNT solutions due to intentional or unintentional interference.
There are three elements of PNT:
1.Positioning – the ability to precisely determine one’s location and orientation, predominantly two-dimensionally although three-dimensional orientation can be determined when required.
2.Navigation – the ability to determine both the current and desired position (either relative or absolute), and apply corrections to course, orientation, and speed to attain the desired position – from anywhere in the world, from sub-surface to surface, and from surface to space.
3.Timing – the ability to acquire and maintain accurate and precise time from a standard (such as UTC), anywhere in the world and within user-defined timeliness parameters.
AMSA notes that ships will increasingly rely on electronic PNT information, primarily GNSS-based. This will result in safety and efficiency benefits, including improved accuracy and integrity monitoring. To enable marine GNSS receiver equipment to make use of SBAS, changes to onboard equipment may be necessary to meet IMO and International Electrotechnical Commission (IEC) standards.
As already mentioned, over-reliance on GNSS can make ships vulnerable to signal interference, jamming, or spoofing, compromising navigation. Therefore, the integration of PNT information can provide several benefits to coastal navigation; navigation in environmentally sensitive sea areas; port approaches; and harbour manoeuvring.
