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AIS Implementation: a news round-up
Fred Pot, Principal of Marine Management Consulting, gives us the latest news
and developments about Automatic Identification Systems on vessels
THE REMOTE Automatic Identification to process AIS information in a timely showed just 30 minutes (12.1 nm) before DSC from the AIS standard may be possible
System (AIS) which the International fashion, a high-speed, 38.4 kb per second passing, which was well after each ship in the future, but type approved transpon-
Maritime Organisation (IMO) has version of the same protocol has also been had selected its channel. See ders will probably need to have DSC capa-
embraced in principal and will require developed (NMEA 0183-HS / IEC 61162- http://www.bcmarine.org/wmc/uais/ bility even if it will never be used.
ships to carry in future, is currently 2). This new version was published on July cruise.htm for Sea Princess' ECDIS screen
being defined by government entities 1, 2000. prints of this encounter. In heavy traffic areas USCG feels that the
and by commercial interests. AIS con- This means that producers of ECDIS, Although formal analysis of the test throughput capacity that AIS provides
sists of a shipboard transmitter that digi- radars and integrated bridge systems can data has yet to be completed, bridge with channels 88B and 87B (19.2 KB per
tally broadcasts its name, position, speed now start to develop and test a single stan- teams reported noticeable differences in Second) will prove to be insufficient and
and course along with other details dard interface that allows their equipment range and bearing between AIS and that a third AIS channel will be needed
via VHF to nearby ships and coastal to be connected to any type-approved ARPA targets of the same ship, thus rein- for base stations to interrogate ships, to
authorities. transponder. forcing the need for consolidation and broadcast safety messages and to re-
An AIS 'transponder' also has two avoidance of screen clutter. (Since AIS broadcast AIS information it receives. For
VHF radios that receive this information Writing software for an interface between position information was updated every 2 these purposes USCG intends to remote-
from other ships. Although a transpon- ECDIS/radar and an AIS transponder is seconds for this trial, latency cannot ly switch one of a ship's transponder's
der has a small, 3-line display to display one thing; displaying AIS information on explain the differences). two radios temporarily from 87B or 88B
the information it receives, it is typically screen is quite another. AIS provides much AIS really shone, however, when it to this third channel.
connected to a ship's electronic chart or more information than radar, so new sym- came to filling in the many radar blind While this solution increases the
radar to provide a more practical display bols and rules will be needed in order to spots in Alaskan and British Columbian capacity available for AIS traffic in an
of AIS information. display the many and varied things which fjords. In one instance, the range between area by 50 per cent, it does not increase
AIS can provide, such as actual current Regal and Sea was only 6.3 nm, but there the capacity of an individual ship's
IMO will likely require new ships con- velocity observations. was a 762 m high island in between them. transponder.
structed after July 1, 2002 to carry a Singapore is planning to test display AIS was able to show a complete picture
transponder. Existing passenger ships and alternatives on three Marine and Port of the traffic situation to the officer on In addition to 87B, MariTEL
tankers will need to carry a transponder a Authority (MPA) vessels starting this fall. watch almost irrespective of coastal (www.maritelusa.com) also owns many
year later, with other existing ships over An international committee will direct the geography. more marine VHF frequencies in the US.
30,000 GRT, to follow a year after that. By test. Unfortunately this committee lacks To assist in optimally spotting future In alliance with several partners, it intends
2008 even small (>300 GRT) ships that are representation from ship operators, and AIS base and repeater stations along a to build 286 330ft high towers, each with a
not involved in international voyages will MPA vessel crews are not necessarily rep- rocky coast, an analyst will use the AIS minimum range of 50 nm to serve the
be required to carry one and many coun- resentative of important future AIS users: test data to attempt to fashion a model marine industry, with analog voice as well
tries are likely to require domestic tonnage bridge teams sailing on large ships with that predicts AIS range given the charac- as 14.4 kb per second data transmission
to carry transponders well beyond IMO's sophisticated integrated bridge systems. teristics of the surrounding terrain. This services. All base stations will be connect-
requirements both in starting date and in Hopefully, ship operators will involve will not be easy because AIS' range, just ed to a central control centre that will
minimum ship size. themselves in the process soon to make like VHF's range, turns out to be affected route voice calls and data transmissions,
But first AIS standards have to be sure the standard will work for their by characteristics beyond those that are verify and charge credit cards and provide
defined. bridge teams. easily measurable, like terrain height customer service 24x7.
Because there is much testing to be between transponder antennas. In the The network has been dubbed MariNET
To make sure that transponders from dif- done, AIS symbols and display rules will test, so far, AIS range peaked at about 71 (a name that is already used by a British
ferent manufacturers can understand each probably not be complete until the fall of nm but also was as short as 12 nm, company that is in a similar business). The
other, the International Electrotechnical 2001. although the latter may have been base stations have been designed to sup-
Commission is in the process of defining caused by a combination of terrain port multiple protocols and modulation
performance criteria for type approval of Bridge teams of the cruise ships Regal characteristics and temporary 'technical methods, including the Time Division
transponders (Future Publication IEC Princess, Sea Princess and Volendam have challenges'. Multiple Access (TDMA) protocol which
61993-2). International agreement on these just completed testing AIS in British could be used to communicate with ships
criteria is expected to be reached by Columbia/Alaska under the auspices of In the US, MariTEL acquired VHF that are equipped with AIS transponders.
December of this year. an association of private and government Channel 87B, which has been reserved With such an extensive infrastructure,
In the meantime, two of the transpon- maritime interests (PACMAR). Because for AIS in the rest of the world, from the MariTEL may be able to entice USCG to use
der manufacturers that are actively this test preceded availability of standards government along with many other its infrastructure instead of building its
involved in defining these criteria, are for interoperability between transponders marine VHF channels. USCG is currently own with tax dollars.
working out the detailed issues that, so and standards for interfacing transpon- negotiating with MariTEL to free up 87B To achieve 14.4 kb per second,
far, have prevented actual inter-operabil- ders with other navigational instruments, for AIS. MariNET may use a combination of
ity. "Marine Data Systems (of South the transponders of a single manufacturer According to both USCG Capt. Robert TDMA and Frequency Division Multiple
Africa) and Saab Transpondertech (of (Tideland Signal/MDS) were used and Ross and Thom Belesky, vice president of Access (FDMA). MariTEL hopes to per-
Sweden) have in the last two weeks con- special software was written to interface MariTEL, the negotiations are going well suade VHF radio manufacturers to pro-
ducted an e-mail dialogue regarding the Regal's transponder to its electronic chart and it now seems likely that 87B will duce and sell low cost radio modems that
schedule for interoperability testing and (Transas Marine's NaviSailor 2500) and become available for most approaches to boat owners can use on the network for e-
are at the point of preparing proposed Sea's and Volendam's transponders to their US ports. Similarly, VHF Channel 88B, mail, internet access and receipt of AIS
schedules for this to happen", says Ernie the integrated bridge systems (STN Atlas' which has been reserved as the second position updates from SOLAS ships.
Batty of Marine Data Systems. ChartPilot/MultiPilot II). Once these channel for AIS in the rest of the world and This venture is worth watching as it has
interfaces were available, installation of is currently being used by Federal the potential to drive the implementation
To allow connection of any transponder transponders proved relatively simple Government agencies, will likely be freed of AIS well beyond the boundaries of IMO
to any electronic chart or radar, AIS 'sen- with short cable runs. up for AIS in the US as well. or USCG carriage requirements, a devel-
tences' are added to the current standard Bridge teams were generally pleased Hardware and software to support an opment which would be to the benefit of
communication protocol for navigation with AIS performance. Sea's navigator, for older type of digital radio communication the maritime industry at large.
instruments. This protocol allows ship's instance, reported that he was able to dis- protocol (Digital Selective Calling on VHF
instruments, like differential GPS, auto cuss sailing through separate channels Channel 70) was added to the standard for
pilot, radar, ECDIS, gyro compass, depth between Skagway and Juneau in Alaska AIS transponders mostly because 87B and Fred W. Pot is Principal of Marine
sounder, etc., to communicate with each with Regal, because Regal identified itself 88B were not available in the US. It is not Management Consulting, an AIS
other over serial cables. Because its as an AIS target about 1 hour 40 minutes clear what will happen to this part of the consultancy based in Seattle. He can be
reached via www.uais.org.
throughput capacity is limited to 4.8 kb (39.8 nm) before the two ships passed each standard now that, at least for the US, DSC
per second, which is too limited to be able other. Regal's unidentified radar target seems not to be required after all. Deleting
Digital Ship November 2000 page 26