What is an Automatic Identification System AIS and how does it work?

Automatic identification systems (AIS) transponders are designed to be capable of providing position, identification and other information about the ship to other ships and to coastal authorities automatically.

How does AIS supplement the radar information?

The VHF frequencies used by the AIS are better at detecting around headlands and islands than radar is, allowing detection of targets that are in radar shadow. … AIS is more accurate than radar since it is continuously fed with data from reliable sensors. Radar can have very poor accuracy when tracking a target.

What is the principle of Automatic Identification System?

The principle of AIS is to allow automatic exchange of shipboard information from the vessel’s sensors – inputted static and voyage related data – between one vessel and another and between a vessels and a shore station(s).

What does an Automatic Identification System AIS transponder use to transmit and receive information broadcasts?

The AIS system consists of one VHF transmitter, two VHF TDMA receivers, one VHF DSC receiver, and a standard marine electronic communications link to shipboard display and sensor systems. … Other information broadcast by the AIS is electronically obtained from shipboard equipment through standard marine data connections.

How does AIS connect to radar?

From a Radar screen or the Radar overlay, select Menu > Other Vessels > AIS. Select an option: To indicate the distance from your location within which AIS vessels appear, select Display Range, and select a distance. To show details about AIS-activated vessels, select Details > Show.

Which information on the AIS is considered dynamic information?

AIS transmits, automatically and at set intervals, dynamic information relating to the ship’s course, speed and heading; static information related to the ship’s name, length, breadth; and voyage-related details such as cargo information and navigational status (e.g. underway or at anchor).

Why do ships turn off AIS?

A ship’s crew may turn off its AIS broadcast for a variety of legitimate reasons, but this behavior may indicate that a vessel is hiding its location and identity to conceal illegal activities like fishing in no-take protected areas or entering another country’s waters without authorization.

Which information must automatic identification systems AIS automatically provide to appropriately equipped shore stations vessels and aircraft?

Automatic Identification System (AIS) is a maritime navigation safety communications system standard- ized by the International Telecommunication Union (ITU), adopted by the International Maritime Or- ganization (IMO), that: Provides vessel information, including the vessel’s identity, type, position, course, speed, …

Why do some ships turn off their AIS units?

Because vessels with AIS can ‘see’ each other’s course and speed in real time, AIS is a critical collision avoidance tool. … A frequently cited example of a reason for switching off the AIS is when transiting waters prone to piracy in order to conceal the vessel’s identity, location and course from pirates.

Can the AIS be switch off?

A master may switch off a ship’s AIS if they believe that its operation could compromise the safety or security of the vessel. Examples include transiting high-risk piracy areas where the location of the vessel needs to be kept confidential.

Do pirates use AIS?

AIS is a two-way street when it comes to piracy. … More specifically, ships are advised to leave their AIS transmission on throughout any and all areas of risk but configure it to transmit only restricted data, such as the ship’s identity, position, course, speed, navigational status and safety-related information.

What is the maximum range of AIS?

AIS enables authorities to reliably and cost effectively monitor fishing vessel activities along their coast line, typically out to a range of 100 km (60 mi), depending on location and quality of coast based receivers/base stations with supplementary data from satellite based networks.

What is the benefit of long range AIS detection to you?

What are the benefits of AIS? AIS provides a lot of benefits in terms of traffic monitoring and vessel assistance. Ship owners and maritime authorities greatly rely on AIS to supplement information acquired from traditional radars for location tracking and is used to detect and avoid vessel collisions.

What is the importance of ESP onboard?

Enhanced survey programme gives the specific guidelines for the inspection of hull related items during statutory surveys. ESP has ensured these ships are maintained in a way that ensures the safety of the bulk carriers and tankers.

What is the purpose of ship security plan on board ship?

Ship Security Plan (SSP) is a plan that is formulated to ensure that that the measures laid out in the plan with respect to the security of the ship are applied onboard. This is in place to protect the personnel, cargo, cargo transport units, stores etc from any security-related risks.

What is the difference between Class A and Class B AIS?

The main difference between Class A and Class B units is the power output, Class B transmits at 2W, giving a range of between 8-10 miles, whilst Class A transmits at 12.5W giving a much larger range.

What satellite is used to detect AIS signatures?

Spectrum Decollision Processing Onboard (SDPOB) is the technology for processing AIS data onboard ORBCOMM satellites. It provides the ability to detect more AIS signatures in the most efficient and expedient method available. In any given area, there may be many vessels that are transmitting their AIS information.

How does ship security alert system work?

SSAS transmits a special alert signal «ship-to-shore» which indicates to competent authorities that safety of a vessel is at risk. … A special alert signal shall be transmitted until it’s deactivated or dropped.

Can you describe the 2 classifications of AIS?

AIS information is divided into two classes – classes A and B – depending on the AIS transponder transmitting the AIS information. … AIS of class A In order to avoid that the ships’ AIS systems all speak at the same time, large ships use an AIS system of class A, which is called SOTDMA (Self-Organized TDMA).

What band does AIS operate in?

VHF maritime band
The AIS is a shipboard broadcast system that acts like a transponder, operating in the VHF maritime band, that is capable of handling well over 4,500 reports per minute and updates as often as every two seconds.

How many types of AIS are there?

For a shipboard fitting there are three types of AIS equipment, Class A, Class B and receive only. Class A is intended for vessels where the fit is mandatory.

What protocol that allows AIS to be autonomous and continuously operational?

Self Organizing Time Division Multiple Access
How does AIS work? The heart of the system is a transmission protocol called Self Organizing Time Division Multiple Access (SOTDMA). This protocol is what allows AIS to be autonomous and continuously operational.

What are the three types of AIS information?

Types of AIS

AIS carried on board aircraft to support maritime safety. AIS base stations are non-shipborne stations which can relay information from AtoN and vessels. AIS AtoN which can be a physical aid to navigation or a virtual aid which broadcasts information.