10 Things You Should Know About AIS If You Are In the Shipping Industry

in Maritime Knowledge by

In the age of ultrafast communication and GPS, it is hard to imagine that sailors once relied on the sky (i.e. constellations) to navigate their vessels in the high seas. However, not every sailor was a Viking, and this led to high chances of the ship landing somewhere it is not supposed to be (read: Christopher Columbus).

Fast forward to the 21st century, and we can do nothing but look back in awe at all the challenges sailors used to face back in the days. Since the 1990s, navigation in itself and shipping at large have undergone sea changes, thanks to the rampant evolution in AIS tech.

Now, humans have the rightful luxury of tracking their fleets on the seven seas with the help of a single click in real-time.

What was initially developed to function as a simple collision avoidance tool has now spiraled to form the heartbeat of global ship navigation? Yes, it is the Automatic Identification System (AIS) that we are talking about.

Currently, over half a million vessels actively use AIS for transmitting vessel data (mainly their location), which then gets collected by a receiver network deployed across the globe. FleetMon alone has a humongous database of over half a million vessels with users across 164 countries using FleetMon.com to track vessel movement.

Gone are the days when AIS used to be a tool for accident prevention. It is now a proven source of information for a wide variety of individuals ranging from maritime businesses that leverage its data to predict their growth, to researchers and analysts monitoring the supply chain.

As such, it is ever more important to know about AIS, at least the basics of it. The blog has been engineered for the same purpose, covering the 10 most important points about AIS and how you could benefit from it.

1. What is AIS?

It is a tracking system used primarily for avoiding collisions at sea and monitoring maritime traffic. Each vessel transmits its unique identification, along with its position and voyage information via AIS transponders on board, with a fixed frequency per minute. Ships, satellites, and terrestrial AIS receiver stations in the vicinity of the ship can catch the transmitted data and relay it back to the HQ.

Since 2004, IMO has made it compulsory for all commercial as well as passenger vessels to have AIS transponders onboard. The move was aimed at increasing transparency in the shipping industry.

2. Who developed AIS?

This is one of the most widespread questions asked in the maritime fraternity, especially by navigators, and the answer seems somewhat dubious. There’s no clear-cut evidence as to who ‘created’ AIS and its initial idea, but the industry widely considers Benny Pettersson to be the founding father of the same.

After GPS data was widely made available for civilian use, integration of existing VHF radio technology with GPS position and time gave rise to AIS. This was shortly after the Exxon Valdez disaster, with different countries like the US, the UK, and Sweden working on creating a system that could avert similar disasters.

When it was figured out that data transmitted by one vessel could be captured and transmitted by another vessel in its proximity to land-based receivers, thereby creating an effective internalized network, the idea of AIS got a breakthrough. The effective ‘web’ is what allows us to have a complete picture of the global shipping traffic from the comfort of our offices or homes.

3. What is the use of AIS on a vessel?

In 2004, IMO made it mandatory for all vessels (both passenger and freight) over 300 GT to have AIS Class A transponders switched on throughout its voyage, with temporary suspension allowed in cases where a security threat to the ship arises.

Class B transponders are mostly for smaller vessels like pleasure boats and yachts and are lower in price. Since many countries do not require a license to operate, boat owners chose to voluntarily retrofit into their vessels. Increased visibility on the seven seas can end up saving these small vessels when the weather turns its back.

4. Which data is AIS transmitted?

Various data fields are transmitted via AIS and can be divided into static and dynamic information.

  • Static information: Includes the IMO number of the vessel, its callsign, name, dimension, draught as well as the ETA of the vessel. It is provided by the crew of the vessel and is transmitted every six minutes.
  • Dynamic information: These are the data points automatically transmitted every 2 to 10s, based on the vessel speed and course of the vessel. It includes the vessel MMSI number, AIS navigational status, positional accuracy, course over ground, etc.

Compared to Class A transponders, Class B transponders send less data (not included are IMO number, Draught, Destination, ETA, Rate of Turn, Navigational Status) with a rarer transmitting interval.

5. What is the range of AIS signals?

Antenna height determines the range of the AIS signals.

Ship-to-ship connections have a range of about 20 nautical miles or 37 kilometers.

Coastal stations have a radius of reception of about 50-100 kilometers or 37 nautical miles based on the height of the antenna.

6. How frequently is AIS Data updated?

A wide variety of factors affect the frequency of transmission of AIS data, which typically ranges from a few seconds to 3 minutes. The factors are:

  • weather pattern
  • vessel traffic
  • AIS transponder type (Class A or B)
  • and vessel seed.

Another factor that affects the transmission of AIS data is whether terrestrial receiving stations or satellites can catch the data. At FleetMon, every single AIS position report captured by our AIS receiver network is displayed in real-time. For vessels faring further away from the shoreline, only satellite AIS can do the coverage.  For these, position updates provided by satellites can range from a few minutes to several hours.

7. Can AIS data be changed?

AIS can be manipulated by sending out false information, triggering false collision warnings at times. This can even influence the automatic steering system that operates in unison with the AIS data.

Other instances where AIS data ends up being changed:

  • Foreign vessels plying in international waters manipulate AIS data to let go of the country’s Coast Guard.
  • Pirates change the positional data of a vessel to mislead international naval forces in case of a distress call.
  • Vessels carrying illegal cargo onboard actively try to conceal their identity to prevent any alarms from going off.

At FleetMon, we actively filter out jumps from ships and clean up the system to prevent any false alarms.

8. Who uses AIS?

Sea traffic within 20 miles can be monitored by sailors via AIS transmitters. On the other hand, port personnel uses this to monitor vessel traffic in the port and the adjoint anchorage.

Notwithstanding shipping personnel, hundreds of thousands of people across the globe rely on FleetMon and other AIS providers for giving them a cohesive global picture of the supply chain at sea. Crew members get tracked by family members, vessel operators monitoring their fleets and finding new potential business opportunities via maritime business intelligence, etc, the application of AIS is endless.

9. Why is AIS data not free?

FleetMon always makes sure that the last vessel position captured by our terrestrial AIS is available for free for our users. It gets showcased on the map on our web portal and mobile application. This data is captured by our aforementioned shore-based antennas hosted by AIS partners worldwide. Those have limited connectivity: Once ships sail on the open seas, our shore-based AIS ceases and satellite AIS tracking comes into play. For this, satellites need to be brought into a specific orbit, and this process requires a lot of capital. Hence, this tracking data costs a small fee.

10. How can I track my vessel using AIS?

If your vessel has a working AIS or is added to FleetMon’s AIS database, you simply need to enter its name or IMO number to view the vessel on the map or in FleetMon Explorer for real-time vessel tracking.

In cases where your private vessel is a brand new one and you want to add it to our database, an AIS class B transponder needs to be installed on your vessel. Take care in entering the correct static information and leave your transponder switched on. Bingo, shortly after, you can view your vessel on the FleetMon database!

Do you live in an area with lots of ships passing by? Reach out to us to become our AIS Partner and enjoy lots of benefits. If you’re interested to set up a terrestrial AIS receiving station for FleetMon at your house or company building (costs covered by FleetMon), please contact us by submitting the AIS partner form.