What is AIS (AIS)? AIS: Automatic Identification System AIS base station.

Types of AIS stations

SHIP EQUIPMENT AIS

AIS stations are installed on mobile and stationary objects.

Mobile (or mobile) stations include:

Class A ship stations;

Class B ship stations;

Stations on hovercraft (search and rescue vessels);

Stations installed on navigation objects;

Portable man-portable stations used by pilots on board a ship.

Fixed stations include:

base stations;

repeater stations.

Class A stations fully comply with all international requirements and must be installed on conventional ships in accordance with the requirements of Chapter 5 of SOLAS. Class B stations do not have a minimum display for displaying information, do not require entry of voyage information. Such stations are intended for installation on non-conventional vessels (pleasure, yachts, fishing vessels).

AIS stations may be installed on aircraft for search and rescue operations.

Stations installed on navigational objects (AtoN) act as a radio beacon and transmit a special message 21 containing its own identifier, AtoN type, accuracy sign, location, type of navigation sensor.

Base stations include AIS installed at coast stations participating in the vessel traffic control system (VTS). Base stations provide monitoring, i.e. surveillance of ships in a certain coastal zone can transmit special binary messages containing information about ships that are not equipped with AIS, but are accompanied by coastal radars, and also perform many other functions.

To expand the coverage area of ​​a coastal base station, for example, to monitor the water area hidden by the coastal relief, repeaters are used - repeater stations.

The AIS station (or transponder) consists of two functional units: the main unit and the control and display panel (PUO). On fig. 4.1 shows a set of AIS ship equipment manufactured by Transas.

The main unit provides all the AIS functions and can work autonomously without an ACS. The SCP is designed to interact with the operator. The control unit receives control commands from the main unit and transmits manual input commands to the main unit. The exchange between the main unit and the control unit is carried out through the serial RS-422 interface at a speed of 9600 bps.

Structural scheme ship AIS class A is shown in fig. 4.2. The main unit of the AIS class A ship station includes:

Two AIS-1 and AIS-2 channel receivers with TDMA decoders with the ability to switch to regional channels; ( TDMA (Eng. Time Division Multiple Access - multiple access with time division) - a method of using radio frequencies, when several subscribers are in the same frequency interval, different subscribers use different time slots (intervals) for transmission.)

Transmitter switchable to AIS-1 and AIS-2 channels and to regional channels;

DSC receiver and decoder (channel 70); ( Digital selective calling (DSC) (eng. Digital Selective Calling, DSC) - a type of communication used for the initial call of ship and coast stations with different priorities for the purpose of further radio communication by radiotelephone or radiotelex. DSC involves the transmission of short formalized messages, encoded using binary characters in the MF, HF and VHF bands.)

Rice. 4.1. Ship equipment manufactured by Transas: main unit, control and display panel, VHF AIS antenna, combined GPS/GLONASS type GNSS antenna

Antenna switch receive/transmit;

Antenna AIS VHF;

GNSS antenna;

Built-in GNSS receiver;

DSC and TDMA signal encoders;

Microprocessor controller that controls the operation of the equipment;

Built-in Integrity Test (BIIT - Built-In Integrity Test).

The following channels (ports) are provided for connecting the main AIS unit to ship navigation devices. Three input ports:

Port 1 (SEN1) - for connection to an external GNSS ship navigation receiver;

Port 2 (SEN2) - for connection to a gyrocompass;

Port 3 (SEN3) - for connection to the angular rate sensor.

To exchange information with external devices bidirectional ports are provided:

MAIN port - for connection to an electronic charting navigation system (ECDIS);

AUX port - for connection to a pilot personal computer;

Port LR - for connection to long-distance communication equipment;

RTCM port - for inputting differential corrections from the differential correction receiver and for issuing differential corrections received via the AIS channel.

Rice. 4.2. Structural diagram of ship AIS class A

The BIIT port is used to connect to the alarm system on the bridge. Built-in health monitor provides error detection in transmitted information and in the received data. If the data of any sensor (for example, a gyrocompass) does not enter the AIS equipment, then a "no data" signal is issued. If the AIS equipment fails, an alarm is generated and data transmission is stopped.

The minimum (text) display and keyboard provide the ability to enter static and voyage information into the AIS equipment, as well as enter and display text messages related to maritime safety. Structurally, the minimum display and keyboard are made as a separate small-sized device or combined with the main AIS device. The minimum display must show data for at least three vessels, including bearing, range, and the name of the target vessel.

Bearing in navigation, the horizontal angle between the northern part of the meridian of the observer and the direction from the observation point to the object; measured clockwise from zero (direction to the north, N) to a full arc of a circle (360 °, or 32 rumba).

Other ship data can be displayed by scrolling text horizontally. In this case, the bearing and range data are stored on the screen. By scrolling vertically, data on other target vessels can be displayed. When pairing the AIS equipment with the ship's navigation display, all the functions of input and display of information are implemented on the interfaced display.

The built-in GNSS receiver provides time synchronization of the AIS equipment and is a backup source of information about the vessel's position. The main source of information about the position of the vessel in the AIS is an external ship's GNSS receiver used for navigational purposes and interfaced with the AIS. Differential corrections transmitted by DGNSS coast reference stations in the beacon range can be transmitted from an external differential correction receiver to an internal GNSS receiver.

One of the ways to improve the accuracy of positioning using satellite navigation systems (GPS, GLONASS) are differential corrections

Differential corrections may also be transmitted by the coast station over the AIS link and transmitted to the internal GNSS receiver.

AIS uses position information from external and built-in GNSS receivers. AIS constantly transmits information about current coordinates and time. When transmitting position information, an AIS ship station automatically selects an available source of information with the highest priority.

AIS equipment should automatically select the position source with the highest priority. If the source is changed, the AIS shall automatically switch to the source with the higher priority (after 5 s if the priority is decreased, and after 30 s if the priority is increased).

During this time period, the last valid position value should be used.

Vessel movement control systems.

AIS(Automatic identification system, (English) AIS Automatic Identification System) - in navigation, a system used to identify ships, their dimensions, heading and other data using VHF radio waves.

Recently, there has been a tendency to interpret AIS as (Automatic Information system, (English) AIS Automatic Information System), which is associated with the expansion of the functionality of the system compared to the ordinary task of identifying ships.

In accordance with the SOLAS convention, it is mandatory for ships with a displacement of more than 300 tons. Ships and yachts with a smaller displacement can be equipped with a class B device. Data transmission is carried out on international communication channels AIS 1 and AIS 2 in the SOTDMA protocol (eng. Self Organizing Time Division Multiple Accsess). Frequency modulation with GMSK keying is applied.

AIS is designed to improve the level of navigation safety, the efficiency of navigation and the operation of vessel traffic control systems (VTS), environmental protection, ensuring the implementation following functions:

• as a means of avoiding collisions in ship-to-ship mode;
• as a means of obtaining information about the vessel and cargo by the competent coastal authorities;
• as a ship-to-shore VTS tool for vessel traffic management;
• as a means of monitoring and tracking ships, and in search and rescue (SAR) operations.

AIS system includes the following components:

• VHF transmitter,
• one two VHF receiver,
• global satellite navigation receiver (for example, GPS, GLONASS),
• modulator/demodulator (converter of analog data to digital and vice versa),
• microprocessor based controller
• equipment for input-output of information to control elements

The action of the AIS is based on the reception and transmission of messages via VHF waves. The AIS transmitter operates at longer wavelengths than radars, which makes it possible to exchange information not only over direct distances, but also in terrain with obstacles in the form of not very large objects, as well as in bad weather conditions. Although one radio channel is enough, some AIS systems transmit and receive on two radio channels in order to avoid interference problems and not disturb the communication of other objects. AIS messages may contain:

• identification information about the object,
• information about the state of the object, obtained automatically from the controls of the object (including some electric and radio navigation devices),
• information about the geographical and time coordinates that the AIS receives from the global navigation satellite system,
• information entered manually by facility maintenance personnel (security related).

Transfer of additional textual information between AIS terminals (paging) is provided. The transfer of such information is possible both to all terminals within the range, and to one specific terminal.

In order to ensure the unification and standardization of AIS in the International Radio Regulations, two channels are assigned for use for AIS purposes: AIS-1 (87V - 161.975 MHz) and AIS-2 (88V - 162.025 MHz), which should be used everywhere, with the exception of regions with special frequency regulation.

Transmission speed digital information in the AIS channel, 9600 bps is selected.

The operation of each AIS station (mobile or base) is strictly synchronized in UTC time with an error of no more than 10 µs from the built-in GNSS receiver (in the Russian Federation, according to the signals of the combined GNSS GLONASS/GPS receiver). To transmit information, continuously repeating frames with a duration of 1 minute are used, which are divided into 2250 slots (time intervals) with a duration of 26.67 ms.

Text uses 6-bit ASCII codes

Static information:

• MMSI number
• International Maritime Organization (IMO) number
• Radio call sign and name of the vessel
• Dimensions
• Type of craft
• Antenna position data (from GNSS Glonass or GPS)

Data is transferred every 6 minutes

Dynamic Information:

• Location (latitude and longitude)
• Time (UTC)
• Age of information (how long ago it was updated)
• Heading true (relative to the ground), heading angle
• True speed
• Roll angle, trim
• pitching angle
• Turning speed
• Navigation status (for example: Unable to steer or Restricted in ability to maneuver)

and other information from repeaters and sensors of electro-radio navigation devices and systems.

AIS (AIS)– automatic identification systems, sometimes called informational, since in modern conditions the functionality of the system is no longer limited to the identification of ships - they are designed to maintain a high level of safety and efficiency of navigation. The SOLAS Convention establishes the mandatory application automatic identification systems AIS on cargo ships from 300 registered tons for international flights and the rest - from 500 registered tons, as well as on all passenger ships.

AIS differ in class - A or B. A full-featured system of class A is usually meant by default, in particular, all of the above applies to AIS class A. AIS class B designed for installation on the so-called "non-conventional" ships, that is, those who, by their characteristics, do not fall into the list of ships that are subject to the requirements of the IMO Resolution (International Maritime Organization). AIS class B may not have its own display and keyboard and be connected to some kind of navigation equipment. To position the ship in AIS class B a built-in GNSS receiver is used.

The main purpose of automatic ship identification systems is to prevent collisions. Solving this problem by means of AIS, rather than radar, was proposed in 2000, after which it was recognized by the IMO as extremely effective and mandatory for installation on large ships. Despite the fact that with the help of radars it is quite possible to obtain information about the environment of the vessel and evaluate the dynamics of movement, this does not guarantee the prevention of emergency situations. AIS offers a comprehensive solution based on the exchange of detailed ship information, allowing you to have a complete understanding of the navigation situation at any time.

Automatic identification system operates in the VHF band by transmitting and receiving messages of a certain format containing dynamic and static information. During the exchange, identification information about the vessel, coordinates of the vessel, parameters of its movement (course, speed, angular velocity), parameters of the vessel itself, including call sign, type, dimensions, type of geopositioning system, etc., as well as information about the route, cargo , the number of people on board.

Information received from all road users AIS is displayed in a tabular form with simultaneous drawing on the MFD maps, which makes it possible to control the mutual movement of nearby vessels with a high degree of accuracy and awareness and thereby prevent their accidental collision. Accurate assessment of the navigation situation, made available thanks to the equipment AIS, had the most positive impact on the safety of navigation, especially in regions with the most dense traffic.

Technically, equipment AIS works for more low frequencies(162 MHz) than conventional radars, thereby having greater opportunities for the propagation of their signals both in line of sight and in geographically difficult areas, since long waves bend around obstacles better and generally propagate better under different weather conditions. The reception range can be up to forty nautical miles under ideal conditions, which, of course, also depends on the height of the antenna and the power AIS transmitter.

AIS class B as simplified devices are characterized by reduced power and work up to about five miles, which is quite enough for small vessels. Also AIS class B distinguishes the lower priority of the possibility of signal transmission compared to AIS class A, which means the need for free space in the air of radio exchange between AIS class A.

Some marine radios from world-famous manufacturers, for example, Icom supply their devices AIS receivers, allowing you to track the movement of ships in the visibility zone, not on the display of a separate device, but directly using such a radio station. Such a solution is very attractive and does not require additional costs, which is a great success in the case of a small vessel, but it is necessary to put up with the fact that the full use of the information received will be limited to the radio display, on which it will be difficult to see the table, and even more so the map.

A good solution from the point of view of a combination of costs and informativeness is the so-called AIS receiver. AIS receiver is a compact device without any means of interactive interaction, capable of receiving information AIS and transmit it over the NMEA protocol to a visualization device such as an MFD, chartplotter, or even a PC or mobile device. In any case, regardless of the type used AIS, possession of information AIS is very important when managing a ship, so its analysis is of decisive importance from the point of view of organizing traffic safety.

The catalog of the online store of the company "" includes all categories of equipment AIS and its periphery:

Equipment AIS represented by the most famous brands of world-class navigation equipment manufacturers, such as, and many others. The company's specialists Marinec» work with any types of ship equipment, carry out its supply, installation, commissioning and Maintenance regardless of the type of vessel, they have impressive experience in equipping ships and solving individual problems the highest level difficulties. Contacting the company Marinec”, the client can be sure of the authenticity and quality of the offered equipment, as well as receiving the most up-to-date information on the legislative norms governing the industry regarding the use of certain types of ship equipment.

The seeming emptiness of the sea space can only mislead an ignorant person. All people who are in one way or another connected with shipping and navigation know that the sea is quite crowded. An illustration of this can be cases when a tanker crashes into a dry cargo ship, or a boat crashes into a yacht. Unfortunately, these cases are not uncommon. To prevent such incidents, a set of AIS equipment is installed “on board”.

The Automatic Identification System (AIS) provides real-time exchange of navigational and other information related to the safety of navigation between ships and other AIS stations via special channel radio communications. To transmit and receive information in the AIS, a VHF transponder is used, providing a range of 25-30 miles, depending on the height of the antennas. One of the reasons for the emergence of AIS was the existing limitations of radar and ARPA to solve the problem of preventing collisions between ships. AIS, like radar, is a vessel position information sensor.

The advantages of AIS, which eliminate some of these limitations in solving ship collision avoidance problems, are as follows:

• Mutual exchange of coordinates defined with high precision using GPS. In practice, this means that with an accuracy of 10 meters it is possible to determine where the route of the nearest vessel will pass.
• The operation of the AIS is not affected by precipitation and sea waves, as is the case with the use of radar, which makes it possible to observe small vessels in rough seas.
• Collision avoidance will also be facilitated by the mutual exchange of information between traffic participants about the type of vessel, its draft, size and navigational parameters, as well as planned maneuvers. The possibility of losing target tracking is practically excluded, while ARPA and Radar allow such a possibility under certain conditions. The transmission of call signs or the name of the vessel provides the possibility of addressing the vessel via VHF in incomprehensible or dangerous situations
• The ability to detect targets in the shadow sectors of radars (beyond the island, around the bends of the river, etc.)
• Mutual exchange of information between ships about the type of ship, its draft, dimensions and navigational parameters, as well as about the planned maneuvers, ensures the prevention of ship collisions
• Modern software applications allow you to interact mobile devices(smartphone, tablet, Personal Computer) with AIS, which makes the use of the complex more convenient

• AIS Seapilot AIS CTRX Graphene
• Chartplotter STANDARD HORIZON CPN700i
• VHF antenna SCOUT KS-22
• GPS antenna SCOUT NAV-6

Features of AIS Seapilot AIS CTRX Graphene:

• Ensuring the safety of navigation
• 50 channel GPS receiver
• Silent mode - disable data transfer
• Availability of a mini-USB port
• Compact dimensions
• Integrated NMEA multiplexer

The Standard Horizon CPN700i is a chartplotter with a built-in WAAS/GPS antenna certified by the Russian Maritime Register of Shipping (RMRS). The device is equipped with a 7-inch touch LCD display, information from which is easy to read even in sunlight.



Features Standard Horizon CPN700i:

• Certified by RMRS
• Compatible with NMEA0183 and NMEA2000
• High screen resolution 800x480, bright backlight 1000 nits
• Wi-Fi, built-in web browser and media player
• USB port: the ability to connect a memory card to watch movies, pictures and play music
• Optional C-Map 4D cartography
• Internal 50-channel WAAS GPS antenna
• Split the screen into two parts to view the map with different settings increase
• Compatible with FF525 fish finder
• One NTSC or PAL video input
• Display of data received from a VHF radio with DSC

SCOUT KS-22- a classic marine frequency band antenna from the Italian manufacturer SCOUT. The length of this model is 1.5 m; gain - 3 dB. The antenna pin is made of fiberglass. Special paint with anti-ultraviolet filter avoids discoloration of the antenna.
This model Marine band antennas are ideal for use on motorboats.

The work was presented at the HiTB conference in Kuala Lumpur 2013. Presentation slides are available at the link.

From the official Trend Micro blog:

Trend Micro researchers have found that AIS (Automatic Identification System) security issues allow intercepting communications between ships, creating "ghost ships", sending SOS or collision messages, or turning off AIS altogether on any ship.

It seems to me that those who have researched the security of these systems (AIS) have had a good time getting a portion of the fun. But, "safety" has nothing to do with it.

Automatic identification systems for ships

AIS is automatic system tracking that is established and used by ships and navigation services to identify and locate ships by exchanging data with other nearby ships, AIS ground stations, and satellites. When satellites are used to transmit messages, then such communication is designated Satellite-AIS (S-AIS). The information received through AIS supplements the data obtained from the radar, which is still the main source of navigation for water transport.

AIS is used for the following purposes:
Data exchange between ports and ships
Communication between ships on the high seas
Navigation, heading, position and speed

Where applied:
Management Service maritime traffic
Collision Avoidance
Coast Guard Service
Assistance in navigation
rescue operations
Short messages, such as the weather forecast

The data (unique identification number, position, heading and speed) that these tracking systems provide is displayed either on screens or on ECDIS. Automatic identification systems help navigators and various maritime services to keep track of maritime transport and its movement. The heart of the system is a standard UHF transmitter and satellite system positioning such as LORAN-C, GPS, or Glonass, plus other additional navigation sensors, such as a gyrocompass or an angular rate sensor. Vessels equipped with AIS transceivers and transponders can be monitored from land through special base stations located along the coast, or through satellites equipped with equipment for receiving and transmitting AIS signals.

The transponders automatically send their position, speed and navigation status through the built-in UHF transmitters at regular intervals. Information is taken from the ship's navigation sensors, usually a satellite navigation system or a gyrocompass. Other information such as vessel name and UHF ID is programmed into the equipment when it is installed. Signals are received by AIS transponders installed on other ships or ground stations, for example, a ship traffic control system. The resulting data is then projected onto screens or interactive maps for further analysis and coordination of movement.

The conclusion reached by the researchers is that the identification system of the courts can be quite easily used for all sorts of "dirty things". In essence, AIS is a conventional UHF radio that transparently transmits various kinds of navigation data, which means that all safety problems are related to the radio. To say that the AIS is completely hacked is at least not correct, if only for the reason that this system was developed at a time when the danger of intercepting this data was minimal. Now, with the advent of software-defined radio communication systems, the task of intercepting and retransmitting these messages has been greatly simplified.

Let's now analyze the possible scenarios for the malicious use of these systems, which the researchers cite in their report.

Probable collision

Imagine for a moment that we have a tanker. And now the navigator is standing in the cockpit and, suddenly, a signal appears on the screen about a possible collision with another ship. By the way, all such signals are recorded in a kind of “black” box (the same as on airplanes or racing cars) and must be confirmed by the navigator. At this point, the navigator must perform strictly regulated actions and compare potentially dangerous data with indicators of other systems, at least from radar, satellite navigation systems, and visually. As a result, the event will be fixed and the alarm will be cancelled.

Man overboard

A similar scenario is with a ship where the crew is alerted to another ship in distress. In most cases, such information is immediately transmitted to the ground to the coast guard, which will coordinate all subsequent actions. They are obliged to double-check the received data and notify the team of further actions. As a result, almost all the risks considered by the researchers in their report are minimized.

Disabling AIS transponders on other ships

In some cases, the ship's crew is allowed to completely disable their identification systems. In this case, there are clear rules that describe the actions of the team, for example, constant visual observation.

Changing weather data

AIS is just one of several sources of weather data. The data received through this channel is (usually) cross-checked and checked against other sources.

All other abuses of these systems are online services, such as marinetraffic.com, where the data is provided exclusively in information purposes and therefore unlikely to harm anyone.
From the very beginning, ship identification systems were designed to be open, and most likely will remain so in the near future. The introduction of encryption will mean a huge change as all equipment on the ships will need to be changed. Since most of the risks are negligible, I think the International Maritime Organization is unlikely to review the safety of this system.