Realities of S-AIS

Realities of S-AIS

Illegal fishing, piracy, inadvertent nature preserve trespass and damage to ships are some of the most discussed topics at the latest shipping and maritime developer conference, SEADEVCON in September 2018.  Experts agree that to tackle these issues, better and more accurate monitoring of vessels is of critical importance. The Automatic Identification Systems (AIS) transmitted information about vessels' identity and location provide a source for much needed, more accurate insight into marine traffic. But what exactly is AIS and how can we benefit from it?


This series of blogs and articles will share what we at Maerospace have learned about the realities of global AIS and Satellite-AIS (which will refer to as simply AIS from here on). Over the past decade, we have worked with every satellite AIS supplier and with users and analysts from around the world.  In our work to provide a vastly improved maritime domain awareness data feed using advanced analytics, we have developed a deep understanding of what really goes on in the complex global network of sensors that support AIS. Our goal in this series is to share what we have learned in hopes that this incredibly valuable resource can continue to be enhanced. With proper understanding of the system, this unique global resource can be a critical tool to help save lives, guard the borders, protect the environment and enhance trade.

This is not another beginner’s guide to AIS or S-AIS.  Instead we are going to delve into the workings of AIS as system for understanding the maritime domain: How AIS is Used, Myths about AIS, the Quality and Timeliness of AIS data, Satellite-AIS Realities and the Future of AIS for Maritime Domain Awareness.


Coastal versus Satellite AIS

To kick off our discussions, let’s explore the differences between these two systems.  Most S-AIS data providers will include a coastal (Terrestrial) feed as part of their overall service. As valuable as this is, it can create misleading quality metrics. Coastal data is collected by a receiver usually mounted on a tower near ports.  These receivers are inexpensive, and thousands have been distributed around the world.  Receivers are deployed by nations, companies and individuals and there are no restrictions on their use. Many companies have networks of individuals who place a receiver at their homes with a view of the sea and integrate the data received into a global view.   The range of coastal receivers is controlled by three factors: the height of the antenna, the presence of any blockage (mountains, buildings, etc.) and the quality of the installation, including the degradation caused by exposure to the elements over time as well as the quality of equipment, cables and initial installation.  As you can imagine, the quality of the data received ranges from very high to very poor. With a good quality installation and an antenna height of around 100 feet (30m) where it can see the ocean, the receiver has a line of site of about 12 miles to the horizon. AIS uses the VHF frequency which bends around the curve of the earth to some degree and therefore the effective range is approximately 30 to 50 miles. In some instances ships can be seen at 70 miles or more, but at long ranges detection becomes intermittent and unreliable.


We will keep this initial article short and sweet. Next time we will begin a review of the key uses of AIS.  Come back (or email us to get an early copy) to dive into the three key uses of AIS:

  • Saving Lives
  • Separating Good Guys from Bad Guys
  • Making and Saving Money


If you find these articles interest or have feedback, we would very much appreciate your feedback.  If you would like to learn more, we have several white papers available. Please contact us at  


About Maerospace Corporation

Maerospace Corporation, based in Canada, is a global supplier of real-time, predictive analytics to the maritime market. Their core product, TimeCaster™ provides a dramatic improvement in the accuracy and completeness of the maritime picture. Our Advisor™ product analyzes this information to detect and provide real-time alerts on anomalous behavior. TimeCaster™ and Advisor™ together deliver the world’s most accurate picture of the maritime domain for maritime authorities internationally as well as for commercial ship and cargo tracking companies. For more information, visit or email us at


About cloudeo

cloudeo operates a unique, vendor independent, data agnostic market platform through which customers can obtain professional geoinformation services from leading national and international providers at low cost.
Services include dedicated solutions for many industries; such as agriculture, urban and landscape planning, logistics, telecommunications, and water management. Customers are provided with high resolution imagery, 3D terrain models, thematic maps, and sensor data for a wide range of applications. The TimeCaster™ service in our cloudeo web app is available on