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WHAT IS THE AUTOMATIC IDENTIFICATION SYSTEM (AIS)? Picture a shipboard radar display, with overlaid electronic chart data, that includes a mark for every significant ship within radio range, each as desired with a velocity vector (indicating speed and heading). Each ship mark could reflect the actual size of the ship, with position to GPS or differential GPS accuracy. By clicking on a ship mark, you could learn the ship name, course and speed, classification, call sign, registration number, MMSI, and other information. Maneuvering information, closest point of approach (CPA), time to closest point of approach (TCPA) and other navigation information, more accurate and more timely than information available from an automatic radar plotting aid, could also be available. Display information previously available only to modern Vessel Traffic Service operations centers could now be available to every AISequipped ship
WHAT IS THE AUTOMATIC IDENTIFICATION SYSTEM (AIS)? Picture a shipboard radar display, with overlaid electronic chart data, that includes a mark for every significant ship within radio range, each as desired with a velocity vector (indicating speed and heading) Each ship "mark" could reflect the actual size of the ship, with position to GPS or differential GPS accuracy By "clicking" on a ship mark, you could learn the ship name, course and speed, classification, call sign, registration number, MMSI, and other information Maneuvering information, closest point of approach (CPA), time to closest point of approach (TCPA) and other navigation information, more accurate and more timely than information available from an automatic radar plotting aid, could also be available Display information previously available only to modern Vessel Traffic Service operations centers could now be available to every AIS-equipped ship With this information, you could call any ship over VHF radiotelephone by name, rather than by "ship off my port bow" or some other imprecise means Or you could dial it up directly using GMDSS equipment Or you could send to the ship, or receive from it, short safety-related email messages 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 It uses Self-Organizing Time Division Multiple Access (SOTDMA) technology to meet this high broadcast rate and ensure reliable ship-to-ship operation HOW DOES IT WORK? 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 shipboard display and sensor 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, 1/7 and tagged with a random timeout of between and 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% throughput for ships closer than 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 With the help of repeater stations, the coverage for both ship and VTS stations can be improved considerably The system is backwards compatible with digital selective calling systems, allowing shorebased GMDSS systems to inexpensively establish AIS operating channels and identify and track AIS-equipped vessels, and is intended to fully replace existing DSC-based transponder systems WHAT AIS BROADCASTS A Class A AIS unit broadcasts the following information every to 10 seconds while underway, and every minutes while at anchor at a power level of 12.5 watts The information broadcast includes: • • • MMSI number - unique referenceable identification Navigation status (as defined by the COLREGS - not only are "at anchor" and "under way using engine" currently defined, but "not under command" is also currently defined) Rate of turn - right or left, to 720 degrees per minute (input from rate-of-turn indicator) 2/7 • • • • • • Speed over ground - 1/10 knot resolution from 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 - 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 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 (at Master's discretion) Estimated time of Arrival at destination - month, day, hour, and minute in UTC (at Master's discretion) TYPES OF AUTOMATIC IDENTIFICATIONS SYSTEMS ITU-R Recommendation M.1371-1 describes the following types of AIS: Class A Shipborne mobile equipment intended for vessels meeting the requirements of IMO AIS carriage requirement, and is described above Class B Shipborne mobile equipment provides facilities not necessarily in full accord with IMO AIS carriage requirements IEC has begun work on a Class B certification standard, which should be completed by 2004 - 2005 The Class B is nearly identical to the Class A, except the Class B: • • • • • • • • Has a reporting rate less than a Class A (e.g every 30 sec when under 14 knots, as opposed to every 10 sec for Class A) Does not transmit the vessel’s IMO number or call sign Does not transmit ETA or destination Does not transmit navigational status Is only required to receive, not transmit, text safety messages Is only required to receive, not transmit, application identifiers (binary messages) Does not transmit rate of turn information Does not transmit maximum present static draught 3/7 Class B devices are not yet available Search and Rescue Aircraft Aircraft mobile equipment, normally reporting every ten seconds Aids to Navigation Shore-based station providing location of an aid to navigation Normally reports every three minutes This may eventually replace the racon AIS base station Shore-based station providing text messages, time synchronization, meteorological or hydrological information, navigation information, or position of other vessels Normally reports every ten seconds AIS CARRIAGE REQUIREMENT On October 22nd, 2003 the Coast Guard published a Final Rule that amended a previously promulgated Interim Rule, that harmonized the AIS mandates of the Safety of Life at Sea Convention, as amended by the 73rd (MSC 73) and 76th Session (MSC 76) , and, the Maritime Transportation Security Act of 2002 (MTSA) , which delineates U.S AIS carriage requirements as follows: Title 33, Code of Federal Regulations § 164.46 Automatic Identification System (AIS) (a) The following vessels must have a properly installed, operational, type approved AIS as of the date specified: (1) Self-propelled vessels of 65 feet or more in length, other than passenger and fishing vessels, in commercial service and on an international voyage, not later than December 31, 2004 (2) Notwithstanding paragraph (a)(1) of this section, the following, self-propelled vessels, that are on an international voyage must also comply with SOLAS, as amended, Chapter V, regulation 19.2.1.6, 19.2.4, and 19.2.3.5 or 19.2.5.1 as appropriate (Incorporated by reference, see § 164.03): (i) Passenger vessels, of 150 gross tonnage or more, not later than July 1, 2003; (ii) Tankers, regardless of tonnage, not later than the first safety survey for safety equipment on or after July 1, 2003; (iii) Vessels, other than passenger vessels or tankers, of 50,000 gross tonnage or more, not later than July 1, 2004; and 4/7 (iv) Vessels, other than passenger vessels or tankers, of 300 gross tonnage or more but less than 50,000 gross tonnage, not later than the first safety survey for safety equipment on or after July 1, 2004, but no later than December 31, 2004 (3) Notwithstanding paragraphs (a)(1) and (a)(2) of this section, the following vessels, when navigating an area denoted in table 161.12(c) of § 161.12 of this chapter, not later than December 31, 2004 (i) Self-propelled vessels of 65 feet or more in length, other than fishing vessels and passenger vessels certificated to carry less than 151 passengers-for-hire, in commercial service; (ii) Towing vessels of 26 feet or more in length and more than 600 horsepower, in commercial service; (iii) Passenger vessels certificated to carry more than 150 passengers-for-hire Note to § 164.46(a): "Properly installed" refers to an installation using the guidelines set forth in IMO SN/Circ.227 (Incorporated by reference, see § 164.03) Not all AIS units are able to broadcast position, course, and speed without the input of an external positioning device (e.g DGPS); the use of other external devices (e.g transmitting heading device, gyro, rate of turn indicator) is highly recommended, however, not required except as stated in § 164.46(a)(2) "Type approved" refers to an approval by an IMO recognized Administration as to comply with IMO Resolution MSC.74(69), ITU-R Recommendation M.1371-1, and IEC 61993-2 (Incorporated by reference, see § 164.03) "Length" refers to "registered length" as defined in 46 CFR, part 69 "Gross tonnage" refers to "tonnage" as defined under the International Convention on Tonnage Measurement of Ships, 1969 (d) The requirements for Vessel Bridge-to-Bridge radiotelephones in §§ 26.04(a) and (c), 26.05, 26.06 and 26.07 this chapter, also apply to AIS The term "effective operating condition" used in § 26.06 includes accurate input and upkeep of AIS data fields (e) The use of a portable AIS is permissible, only to the extent that electromagnetic interference does not affect the proper function of existing navigation and communication equipment on board, and such that only one AIS unit may be in operation at any one time (f) The AIS Pilot Plug, on each vessel over 1,600 gross tons, on international voyage, shall be available for pilot use, easily accessible from the primary conning position of the vessel, and near 120 volt, AC power, 3-prong receptacle In support of this rulemaking, we seek your participation and input (prior to January th, 2004) regarding expanding upon these requirements as well as your comments to a series of questions posed in our Notice: Request for Comments & Public Meeting Announcement You may view a printable copy of our Small Entity Compliance Guide to AIS, or see a copy of this rule, with definitions to the various terms used therein and a copy of the slides used at our our public meeting in New Orleans 5/7 AIS STANDARDS, GUIDELINES AND EQUIPMENT CERTIFICATION • IMO Resolution MSC.74(69), Annex 3, Recommendation on Performance Standards for an Universal Shipborne Automatic Identification Systems (AIS) This standard defines the basic performance requirements for AIS equipment, and was used by ITU and IEC in developing technical and test standards • ITU-R Recommendation M.1371-1, Technical Characteristics for a Universal Shipborne Automatic Identification System Using Time Division Multiple Access in the Maritime Mobile Band The International Telecommunications Union Sector for Radiocommunications formally adopted this standard in August 2001 This is the standard that defines in detail how the AIS works, and as such is the primary AIS standard It can be purchased electronically from ITU ITU gave IALA the responsibility of maintaining technical guidelines for AIS design, and is available from them as "IALA Technical Clarifications on Recommendation ITU-R M.1371-1" • IEC 61993-2 Ed.1, Maritime navigation and radiocommunication requirements Automatic identification systems (AIS) - Part 2: Class A shipborne equipment of the universal automatic identification system (AIS) - Operational and performance requirements, methods of test and required test results The International Electrotechnical Commission formally adopted this standard in November 2001, and a published version is available from IEC This standard defines the certification test requirements for Class A shipborne AIS equipment • • IALA Recommendation on AIS Shore Stations and Networking Aspects Relating to the AIS Service, Edition 1.0, September 5, 2002 This 159-page document is available from IALA IMO SN Circ.227, GUIDELINES FOR THE INSTALLATION OF A SHIPBORNE AUTOMATIC IDENTIFICATION SYSTEM (AIS) These 14 page guidelines, prepared by the International Association of Lighthouse Authorities and adopted by the International Maritime Organization, contains guidelines for manufacturers, installers, yards, suppliers and ship surveyors It does not replace documentation supplied by the manufacturer." CERTIFICATION OF AIS EQUIPMENT IN THE UNITED STATES In June 2002, the FCC released a Notice entitled "Applications For Equipment Authorization Of Universal Shipborne Automatic Identification Systems To be Coordinated with U.S Coast Guard To Ensure Homeland Security" Pending completion of FCC rulemaking, the FCC Laboratory will coordinate review of applications for certification of AIS equipment with the United States Coast Guard to ensure that the equipment meets all applicable international standards and requirements Essentially, AIS manufacturers must the requirements of the FCC's regulations for equipment authorization, 47 CFR Subpart J (beginning 2.901), and the Coast Guard's Navigational and Vessel Inspection Circular (NVIC) 8-01, Approval of Navigation Equipment for Ships NVIC 8-01 describes the certification process for AIS and other navigation equipment described under the newly 6/7 adopted SOLAS V The Federal Communications Commission has requested comments on how its rules should be amended to accommodate AIS certification, in a further Notice of Proposed Rulemaking under Docket PR 92-257 Until these FCC rules are finally adopted, the procedures described in the FCC Notice and the NVIC should apply Current Status of AIS Certifcations in the United States Please see the International Maritime Radio Committee (CIRM) list of AIS manufacturers Also see the following lists of certifications: • • USCG Certifications (Select "Shipborne Automatic Identification System (AIS)") FCC Certifications (after clicking on this link, select the "Generic Search Report", then select "AIS" in the Equipment Class field of the search form) 7/7 ... inexpensively establish AIS operating channels and identify and track AIS- equipped vessels, and is intended to fully replace existing DSC-based transponder systems WHAT AIS BROADCASTS A Class A AIS unit... 26.07 this chapter, also apply to AIS The term "effective operating condition" used in § 26.06 includes accurate input and upkeep of AIS data fields (e) The use of a portable AIS is permissible,... Radiocommunications formally adopted this standard in August 2001 This is the standard that defines in detail how the AIS works, and as such is the primary AIS standard It can be purchased electronically