Marine Communications and Traffic Services (MCTS)
- National Information System on Marine Navigation (INNAV)
- Communications Control System (CCS) for MCTS Program
- Automatic Identification System (AIS)
National Information System on Marine Navigation (INNAV)
Description: The National Information System on Marine Navigation (INNAV) is an operational tool that links all information needed by MCTS officers through an integrated workstation. INNAV uses client-server technology to ensure that up-to-date information is available, in real time, to every officer. The system will permit MCTS to automate manual and repetitive tasks, enable tasks formerly performed on a series of separate systems to be performed on one platform, and will allow outside clients direct access to appropriate MCTS data.
Contact: Mario Bouchard - National Program Specialist - MCTS - Telephone 613-990-5288
Communications Control System (CCS) for MCTS Program
The Communications Control System (CCS) enables MCTS officers to control all radiocommunications at local and remote sites from their workstations. The CCS project replaces equipment in the five CCG regions, at 21 MCTS centres, at 192 remote sites, as well as the Marine Radio Operator Training Simulation equipment at the CCG College. New ergonomic operator console workstations are being supplied for all positions in MCTS centres, and all the Radio and Instructor positions at the CCG College MCTS training facilities. The acquired system is scaleable and configurable to meet not only today’s requirements but also to be able to evolve to satisfy future operational and training needs. The first installations of the new CCS and associated workstations will start in the fall of 2012. The subsequent installations will be spread over a 4-year period with an average of one centre per region each year.
Gaétan Boudreault - National Program Specialist - MCTS - Telephone: 613-998-1510
Automatic Identification System (AIS)
National AIS Service
The Canadian Coast Guard (CCG) MCTS Directorate has taken a proactive role in its commitment to support international efforts to implement AIS standards and institute carriage requirements. The MCTS Directorate in conjunction with Integrated Technical Services (ITS) has initiated an AIS Project Team to implement a national AIS Service to be administered through regional MCTS Centres. A national AIS Service is expected to be fully operational by March 2008.
What is AIS?
AIS is a shipboard broadcast transponder system, operating in the VHF maritime band, that is capable of sending such ship information as identification, position, heading, ship length, beam, type, and draught, hazardous cargo information, to other ships as well as to AIS Base Stations operated by a competent authority. It is capable of handling over 2,000 reports per minute and updates as often as every two seconds. It uses Self-Organizing Time Division Multiple Access (SOTDMA) technology to meet this high broadcast rate and ensure reliable ship-to-ship and ship-to-shore operation.
How AIS Works
Each AIS system consists of one VHF transmitter, two VHF TDMA receivers, one VHF DSC receiver, and a standard marine electronic communications link (IEC 61162/NMEA 0183) to a shipboard display and onboard sensory systems.
Position and timing information is normally derived from an integral or external global navigation satellite system (e.g. GPS) receiver, including a medium frequency differential GNSS receiver for precise position in coastal and inland waters. Other information broadcast by the AIS, if available, is electronically obtained from shipboard equipment through standard marine data connections. Heading information and course and speed over ground would normally be provided by all AIS-equipped ships. Other information, such as rate of turn, angle of heel, pitch and roll, and destination and ETA could also be provided.
The AIS transponder normally works in an autonomous and continuous mode, regardless of whether it is operating in the open seas or coastal or inland areas. Transmissions use 9.6 kb GMSK FM modulation over 25 or 12.5 kHz channels using HDLC packet protocols. Although only one radio channel is necessary, each station transmits and receives over two radio channels to avoid interference problems, and to allow channels to be shifted without communications loss from other ships.
The system provides for automatic contention resolution between itself and other stations, and communications integrity is maintained even in overload situations.
Each station determines its own transmission schedule (slot), based upon data link traffic history and knowledge of future actions by other stations. A position report from one AIS station fits into one of 2250 time slots established every 60 seconds. AIS stations continuously synchronize themselves to each other, to avoid overlap of slot transmissions. Slot selection by an AIS station is randomized within a defined interval, and tagged with a random timeout of between 0 and 8 frames. When a station changes its slot assignment, it pre-announces both the new location and the timeout for that location. In this way new stations, including those stations which suddenly come within radio range close to other vessels, will always be received by those vessels.
The required ship reporting capacity according to the IMO performance standard amounts to a minimum of 2000 time slots per minute, though the system provides 4500 time slots per minute. The SOTDMA broadcast mode allows the system to be overloaded by 400 to 500% through sharing of slots, and still provide nearly 100% through put for ships closer than 8 to 10 NM to each other in a ship to ship mode. In the event of system overload, only targets further away will be subject to drop-out, in order to give preference to nearer targets that are a primary concern to ship operators. In practice, the capacity of the system is nearly unlimited, allowing for a great number of ships to be accommodated at the same time.
The system coverage range is similar to other VHF applications, essentially depending on the height of the antenna. Its propagation is slightly better than that of radar, due to the longer wavelength, so it’s possible to “see” around bends and behind islands if the land masses are not too high. A typical value to be expected at sea is nominally 20 nautical miles.
What AIS Broadcasts
A Class A AIS unit broadcasts the following information every 2 to 10 seconds while underway, and every 3 minutes while at anchor at a power level of 12.5 watts. The information broadcast includes:
- MMSI number - unique reference identification
- Navigation status (as defined by the COLREGS)
- Rate of turn - right or left, 0 to 720 degrees per minute
- Speed over ground - 1/10 knot resolution from 0 to 102 knots
- Position accuracy - differential GPS or other and an indication if (Receiver Autonomous Integrity Monitoring) RAIM processing is being used
- Longitude - to 1/10000 minute and Latitude - to 1/10000 minute
- Course over ground - relative to true north to 1/10th degree
- True Heading - 0 to 359 degrees derived from gyro input
- Time stamp - The universal time to nearest second that this information was generated
In addition, the Class A AIS unit broadcasts the following information every 6 minutes:
- MMSI number - same unique identification used above, links the data above to described vessel
- IMO number - unique referenceable identification (related to ship's construction)
- Radio call sign - international call sign assigned to vessel, often used on voice radio
- Name - Name of ship, 20 characters are provided
- Type of ship/cargo - there is a table of possibilities that are available
- Dimensions of ship - to nearest meter
- Location on ship where reference point for position reports is located
- Type of position fixing device - various options from differential GPS to undefined
- Draught of ship - 1/10 meter to 25.5 meters [note "air-draught" is not provided]
- Destination - 20 characters are provided
- Estimated time of Arrival at destination - month, day, hour, and minute in UTC
AIS plays an important role in increasing the safety of life at sea and the protection of the environment as well as in SAR-applications. The implementation of International carriage requirements for AIS-equipment on SOLAS-ships has been addressed under the SOLAS Convention Chapter V.
Canadian carriage requirements have been addressed in Part 4 (Additional Equipment Requirements) of the
- Every ship of 150 tons or more that is carrying more than 12 passengers and engaged on an international voyage shall be fitted with an automatic identification system (AIS).
- Every ship, other than a fishing vessel, of 300 tons or more that is engaged on an international voyage shall be fitted with an AIS.
- Every ship, other than a fishing vessel, of 500 tons or more that is not engaged on an international voyage shall be fitted with an AIS, but if it was constructed before July 1, 2002 it need not be so fitted until July 1, 2008.
- The AIS shall
- automatically provide information, including the ship's identity, type, position, course, speed, navigational status and other safety-related information, to appropriately equipped shore stations, other ships and aircraft;
- automatically receive such information from similarly fitted ships;
- monitor and track ships; and
- exchange data with shore-based facilities.
- The AIS shall be operated taking into account the annex to IMO Resolution A.917(22), Guidelines for the Onboard Operational Use of Shipborne Automatic Identification Systems (AIS)
- Every ship fitted with an AIS shall maintain it in operation at all times.
- Subsections (4) and (6) do not apply
- where international agreements, rules or standards provide for the protection of navigational information; or
- in respect of ships, other than ships operated for a commercial purpose, owned or operated by Her Majesty in right of Canada or by a foreign government that is a party to the Safety Convention.
Contact: Mario Bouchard - National Program Specialist - MCTS - Telephone 613-990-5288
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