Where did AIS come from? The concept of a transponder for ships has been discussed in various forums since the 1980 s. The initial concept from the

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3 Where did AIS come from? The concept of a transponder for ships has been discussed in various forums since the 1980 s. The initial concept from the maritime sides was to have a means of positively identifying vessels within a VTS similar to the aviation squawking concept. There is a bit of a history with the introduction of the tool we have today AIS and it is important to understand the development process when looking at how the various international organizations have been working to fully develop the system. IMO and IALA have noted that AIS shall not only be effective in a ship to ship mode, but also work with shore infrastructure. ITU b) that the use of a universal shipborne AIS allows efficient exchange of navigational data between ships and between ships and shore stations, thereby improving safety of navigation; c) that a system using self-organized time division multiple access (SOTDMA) accommodates all users and meets the likely future requirements for efficient use of the spectrum; d) that although this system is intended to be used primarily for 4

4 surveillance and safety of navigation purposes in ship to ship use, ship reporting and vessel traffic services (VTS) applications, it may also be used for other maritime safety related communications, provided that the primary functions are not impaired; e) that this system is autonomous, automatic, continuous and operate primarily in a broadcast, but also in an assigned and in an interrogation mode using time division multiple access (TDMA) techniques; f) that this system is capable of expansion to accommodate future expansion in the number of users and diversification of applications, including vessels which are not subject to IMO AIS carriage requirements, aids to navigation and search and rescue; g) that IALA maintains and publishes technical guidelines for the manufacturers of AIS and other interested parties, 4

5 Where did AIS come from? IMO and IALA have noted that AIS shall not only be effective in a ship to ship mode, but also work with shore infrastructure. 5

6 How does AIS work? Put simply, the Automatic Identification System (AIS) is a Very High Frequency (VHF) radio broadcasting system that transfers packets of data over the VHF data link (VDL) and enables AIS equipped vessels and shore-based stations to send and receive identification information that can be displayed on a computer or chart plotter. Especially when used with appropriate graphical displays, this information can help in situational awareness and provide a means to assist in collision avoidance. In addition, AIS can be used as an aid to navigation, by providing location and additional information on buoys and lights. AIS uses a time-division multiple access (TDMA) scheme to share the VHF frequency, also known as the VHF Data Link (VDL). The VDL is divided into 2250 time slots that are repeated every 60 seconds and each AIS vessel in range sends a report to one of the time slots. At the same time, every AIS vessel in range is listening to all the timeslots and can read the reported information. Although Class A and Class B both use TDMA, they are different. Essentially, Class A units use transmissions that are self-organized into existing free slots whereas Class B units listen to the traffic to determine free slots and will make a one-off decision as to when it will transmit a report. Class B is designed with a 'politeness' factor, 6

7 meaning that it will not interfere or cause degradation of the ability of Class A units. There are many different uses for AIS as well. 6

8 What are the types of AIS? AIS Class A is a shipborne mobile AIS unit and has been mandated by the International Maritime Organisation (IMO) for vessels of 300 gross tonnage and upwards engaged on international voyages, cargo ships of 500 gross tonnage and upwards not engaged on international voyages, as well as passenger ships, irrespective of size. AIS Class B is also a shipborne mobile AIS unit, but is not mandated by the International Maritime Organisation (IMO) and has been developed for vessels such as work craft and pleasure craft. AIS on SAR Aircraft Search and Rescue Aircraft may use AIS to assist in their operations. AIS Base Station are non-shipborne units, and are provided by a national competent authority to enable the ship to shore / shore to ship transmission of information. Networked AIS Base Stations can assist in providing overall maritime domain awareness. AIS AtoN provide an opportunity to transmit position and status of buoys and lights through the same VHF AIS process, which can then show up on the electronic chart or computer display. In addition, virtual aids to navigation can be transmitted by AIS, providing additional information where a buoy does not physically exist. AIS SART - Search and Rescue Transmitters using AIS can be used to assist in determining the final locating of a vessel or life raft, as part of the Global Maritime Distress and Safety System (GMDSS). 7

9 Image that demonstrates how some of the various units work together on the same VHF frequency the VHF data link or VDL 8

10 Different ways AIS data is displayed on the ship 9

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12 Click on the logo upper left to activate the movie terrestrial AIS 11

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14 Split room in two have one side all say their first names at the same time, get the other side to distinguish individual names; repeat for other side. AIS Satellite is a bit like trying to listen to everyone speak at the same time, and make sense out of it! Bjorn Narheim studies / Narheim wall data packet collisions 13

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16 Note data available from AMSA website historic AIS data 15

17 The trial on Satellite AIS goals were to: verify ability of AIS via Satellite to extend beyond terrestrial AIS; compare AIS via satellite data with other vessel track data fields to verify accuracy and reliability of the data; verify data format to enable AIS via satellite data to be viewed in both real time and historic (replay) environments; identify any limits and benefits of AIS via satellite in terms of units received (AIS Class A / Class B); area of coverage, refresh rates, logging and storage Did we meet our objectives? We did verify the ability of Sat AIS in the Australian context We did verify that the data was available in real time and for historic analysis (just like any AIS data) All data is being received as expected, but sometimes the lower power units (1W) do not allow every message to be received. 16

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19 Use on pilot boarding helicopters note the number of vessels off Hay Point (movie) trying to pick the right vessel to board 18

20 Note limitations with the trial in WA (headland) and success of trial in Newcastle. Longer ranges seem to limit usefulness. Ongoing work. 19

21 MOB units have been developing, with initial work done on a VHF-DSC MOB. Australia developed a national testing standard for these units (AS/NZS MSLS other than MHz published Feb ). AIS has now made it into MOB units which are available for sale through e- bay. Kannad Safelink R10 SRS Personal AIS beacon Weatherdock easy rescue AIS SART beacon 20

22 Divers can sometimes go missing from large dive groups, or they may be fatigue or have an issue when they surface. An AIS SART like device has been developed to assist divers one that is good to 50m. MucMurdo AIS Smartfind S10 AIS beacon These are not on the two main AIS fequencies, but are being trialled on alternative frequency (160.9) 21

23 In the Torres Strait there is a safety case for small format class Bs that are completely self contained, battery powered and suitable to put in a grab bag. In the area the Torres Strait Islanders travel between islands, using small tinnies (aliminum runabouts) like cars. There are significant safety issues each year, with a number of SAR incidents. As part of a focus effort to improve safety, a number of 406 MHz beacons have been supplied, and a concept of a grab bag is being developed. This grab bag would be available from local grocery stores or Ranger Stations, with a deposit, and would contain safety gear including life jackets; beacons; flares; etc. In addition, the small Class B would be included in the grab bag activated when it goes in so that it is transmitting. The Islander would pick up the grab bag before leaving, then drop it off at the next island (and get the deposit back). The class B would then go back on charge. 22

24 There are a number of issues that Australia is dealing with these are just a few to help promote discussion. As we can see these are units that can be bought on e-bay now so the equipment standard issue may already be too late. The success of AIS means that the key aspect safety of nav may get lost in the noise 23

25 Development of the VHF data exchange system VDES taking the capability of AIS and moving to develop on new frequencies We have a golden opportunity to revolutionize maritime communications At the World Radio Conference 2012, six channels were made available internationally for digital systems, with more available in some regions. The ITU has now laid the groundwork for the use of digitally modulated emissions in the maritime frequency bands - the challenge to the maritime community now is to use this resource effectively. We now have a chance to make the very best of what we have However we can t really change the spectrum it is what it is - a finite resource - and the spectrum will behave in the same way and give the same results pretty much each time you use it (within parameters ) With the development of software defined radio we can begin to look at combining spectrum providing for a wide band of spectrum for data transfer (i.e. taking 25 khz channels and combining to have 50 khz, 100kHz, even 150 khz) So, with the opportunity provided at WRC2012 we can contemplate the development of digital data transfer over these frequencies the development of the VHF data exchange system. In essence, we need to determine how to make the existing spectrum work smarter 24

26 It is difficult to see radio waves, so I'd like to show a bit of a demonstration with light waves. Since I wasn t able to source the correct materials (namely a green laser pointer ) I ll have to make use of a great you tube video from the show QI If you take a laser pointer... And point it at a white balloon. Nothing happens... Just goes a pretty shade of green. Can you adjust the parameters so that the white balloon so that the laser will 'pop' the balloon? Any ideas? (or have any of you seen the show??) Well, if we change a parameter - in this case, put a black dot on the balloon once again position the laser pointer the balloon goes pop! 25

27 If we use the radio spectrum made available at WRC2012 in the VHF maritime mobile band, and change some parameters - we could develop a digital data transmission system for VHF radio that would enable greater amounts of data to be communicated at higher data transfer speeds. We can work to develop the VHF Data Exchange System... There are proposed modulation schemes that might be able to address this and the technical aspects of the VDES have been presented on already. Note - GMSK/FM = Gaussian Minimum Shift Keying/Frequency Modulation /8 D8PSK = pi/8 shifted, 8-ary Differential Phase Shift Keying QAM = quadrature amplitude modulation 26

28 AIS is a very capable system, but it does have limitations. Errors in AIS are seen with manually input data (indication of nav status underway / at anchor; positional information offset by if system uses incorrect datum; incorrect MMSI input) but these are actually quite low in comparison to the number of AIS units in use. Noise with over use of AIS could limit the safety of nav aspect, and the growing market of smaller units (class B both SO and CS TDMA) could desensitize mariners with overloading of targets. Success in AIS, and the development of digital data transfer over analogue VHF, is leading to the development of a new maritime communications capability called the VHF data Exchange System the VDES will look to use the existing spectrum in a manner that will enable more data to be transferred using digital capabilities and software defined radios. 27