Advancing Maritime Domain Awareness through Space-Based Automatic Identification System Technologies

Maritime domain awareness (MDA) is the effective understanding of anything associated with the global maritime environment that could impact the security, safety, economy, or environment of a nation. MDA is essential for ensuring maritime security, safety, and environmental protection, as well as facilitating trade and commerce. However, MDA faces many challenges, such as the vastness and complexity of the maritime domain, the diversity and dynamism of maritime activities, and the limitations and gaps of existing surveillance and monitoring systems.

One of the key technologies that can enhance MDA is the space-based automatic identification system (SAT-AIS). SAT-AIS is a system that uses satellites to receive and relay signals from automatic identification system (AIS) transponders installed on ships. AIS is a short-range coastal tracking system that provides identification and positioning information to both vessels and shore stations. AIS transponders automatically broadcast information at regular intervals, such as vessel identity, position, heading, speed, course, destination, and cargo type. AIS signals have a horizontal range of about 40 nautical miles (74 km), meaning that AIS traffic information is only available around coastal zones or in a ship-to-ship zone.

SAT-AIS overcomes this limitation by using satellites to extend the coverage and visibility of AIS signals beyond coastal areas. SAT-AIS can provide AIS service for any given area on Earth, regardless of the distance from shore or the availability of terrestrial infrastructure. SAT-AIS can also provide near-real-time information on the location and movement of vessels, as well as their identity and characteristics. This can enable a more comprehensive and accurate picture of the maritime situation and activity, as well as support various applications and services related to maritime security, law enforcement, search and rescue, environmental protection, and fleet management.

However, SAT-AIS also faces some technical challenges, such as the high volume and complexity of AIS signals received by satellites, the interference and collision of signals from multiple sources, the detection and mitigation of spoofing and jamming attacks, and the integration and fusion of SAT-AIS data with other sources of information. To address these challenges, various research and development efforts have been undertaken by different actors, such as the European Space Agency (ESA), the European Maritime Safety Agency (EMSA), the International Telecommunication Union (ITU), and several private companies. These efforts aim to improve the performance, reliability, security, and interoperability of SAT-AIS systems and services.

In this blog post, we will review some of the recent developments and achievements in SAT-AIS technology, as well as discuss some of the future prospects and opportunities for advancing MDA through SAT-AIS.

Recent Developments and Achievements in SAT-AIS Technology

One of the main objectives of SAT-AIS technology is to increase the number and quality of AIS signals received by satellites. This can be achieved by improving the design and performance of both satellite payloads and ground segments. For example:

– ESA has developed a new generation of SAT-AIS payloads that use advanced antenna miniaturisation techniques, digital signal processing algorithms, adaptive beamforming methods, and onboard data processing capabilities to enhance the reception and processing of AIS signals in orbit .
– EMSA has implemented a Data Processing Centre (DPC) that acts as a “space node” for integrating SAT-AIS data into its SafeSeaNet (SSN) system. SSN is a European platform that provides information on maritime traffic and incidents to national authorities. The DPC receives raw SAT-AIS data from different satellite operators, performs data validation, filtering, fusion, analysis, and distribution functions, and delivers value-added SAT-AIS services to SSN users .
– ITU has developed a new technical recommendation (ITU-R M.2092) that specifies a new AIS message format for satellite reception. The new format allows for more efficient use of the available bandwidth by reducing the length of AIS messages from 256 bits to 96 bits. The new format also enables better identification of vessels by introducing a new field for vessel registration numbers .
– Several private companies have launched or planned to launch new constellations of small satellites dedicated to SAT-AIS services. For example,
– exactEarth operates a constellation of 10 small satellites that provide global coverage and high detection rates for AIS signals. exactEarth also offers advanced analytics and decision support tools based on SAT-AIS data .
– Spire Global operates a constellation of over 100 small satellites that provide global coverage and high revisit rates for AIS signals. Spire Global also offers various value-added services based on SAT-AIS data, such as vessel tracking, anomaly detection, risk assessment, weather forecasting, and oceanographic modelling .
– Unseenlabs plans to launch a constellation of 20 small satellites that will provide global coverage and high resolution for AIS signals. Unseenlabs also claims to be able to detect and identify vessels that are not broadcasting AIS signals by using radio frequency (RF) fingerprinting techniques .

Future Prospects and Opportunities for Advancing MDA through SAT-AIS

The developments and achievements in SAT-AIS technology have demonstrated the potential and feasibility of using satellites to enhance MDA. However, there are still some gaps and limitations that need to be addressed, as well as some opportunities and challenges that need to be explored. For example:

– There is a need to improve the coordination and cooperation among different SAT-AIS stakeholders, such as satellite operators, data providers, service providers, end users, regulators, and standardisation bodies. This can help to ensure the compatibility, interoperability, security, and quality of SAT-AIS systems and services, as well as to avoid duplication, fragmentation, and conflict of interests.
– There is a need to develop and implement effective mechanisms and policies for sharing and accessing SAT-AIS data and services among different users and applications. This can help to maximise the benefits and value of SAT-AIS data and services, as well as to protect the rights and interests of data owners and users.
– There is a need to integrate and fuse SAT-AIS data with other sources of information, such as radar, optical, infrared, synthetic aperture radar (SAR), or radio frequency (RF) imagery, as well as other types of maritime data, such as vessel registries, cargo manifests, or port state control records. This can help to enhance the accuracy, completeness, timeliness, and reliability of MDA products and services, as well as to enable new capabilities and applications.
– There is a need to develop and apply advanced analytics and artificial intelligence (AI) techniques to SAT-AIS data and services. This can help to extract meaningful insights and actionable intelligence from large and complex datasets, as well as to support various decision making processes and operations related to MDA.
– There is a need to address the ethical, legal, and social implications (ELSI) of SAT-AIS technology. This can help to ensure the responsible and sustainable use of SAT-AIS technology for advancing MDA, as well as to prevent or mitigate any potential risks or harms that may arise from its misuse or abuse.


SAT-AIS is a promising technology that can enhance MDA by providing global coverage and visibility of maritime activities. SAT-AIS technology has made significant progress in recent years, thanks to the efforts of various actors in the public and private sectors. However, there are still some challenges and opportunities that need to be addressed and explored in order to fully realise the potential and value of SAT-AIS technology for advancing MDA.


: ESA. (n.d.). Satellite – Automatic Identification System (SAT-AIS) Overview. Retrieved from
: EMSA. (n.d.). Satellite AIS Data Processing Centre (DPC). Retrieved from
: ITU. (2018). Technical characteristics for an automatic identification system using time division multiple access in the VHF maritime mobile band – Annex 17: Technical characteristics for satellite reception of AIS messages. Retrieved from
: exactEarth. (n.d.). exactEarth – The Global Leader in Satellite AIS Data Services. Retrieved from
: Spire Global. (n.d.). Spire Maritime – Global AIS Tracking & Weather Data Services. Retrieved from
: Unseenlabs. (n.d.). Unseenlabs – RF Geolocation from Space. Retrieved from

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