{"id":48563,"date":"2022-06-06T12:05:27","date_gmt":"2022-06-06T16:05:27","guid":{"rendered":"https:\/\/www.cruisingworld.com\/?p=48563"},"modified":"2023-05-06T18:19:05","modified_gmt":"2023-05-06T22:19:05","slug":"ais-technology-today-vdes-tomorrow","status":"publish","type":"post","link":"https:\/\/www.cruisingworld.com\/gear\/ais-technology-today-vdes-tomorrow\/","title":{"rendered":"AIS Technology Today, VDES Tomorrow"},"content":{"rendered":"\n
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\n\t\t\t\t\t\"Cortex\" <\/div>\n\t\t\t\n\t\t\t\n
\n Garmin\u2019s Cortex currently delivers the most modern user interface of any AIS\/VHF-related product.<\/span>\n Courtesy The Manufacturer<\/span>\n\n\t\t\t\t <\/figcaption>\n <\/section>\n\t\t\n\n\n

Fourteen to 18 knots of southerly breeze flowed across Puget Sound on a gorgeous day this past summer. My friend Jonathan had invited me to go daysailing aboard Dark Star<\/em>, his Riptide 44. We hoisted the square-top main and jib, and sailed uphill from Seattle\u2019s Shilshole Bay Marina past West Point Lighthouse. Glancing at the angle to Port Madison, where we were headed, Jonathan decided that we should hoist the spinnaker. Perfect!<\/p>\n\n\n\n

We were soon ripping toward Port Madison at 11 to 12 knots. Then we noticed a container ship plying the southbound Vessel Traffic System lane. Given that our hands were full of sheets and steering wheels, I was relieved to glance at the chart plotter and see\u2014via the boat\u2019s Automatic Identification System\u2014that the ship was passing clear east of us.<\/p>\n\n\n\n

While AIS has been keeping sailors safe since 2008, newer technologies, including more-capable AIS Class B transmitters and updated hardware, are making AIS safer, more intuitive and more robust. <\/p>\n\n\n\n

Better still, upcoming \u00adregulatory changes to the way AIS interfaces with the rest of the electronic-communications ecosystem are poised to make cruising safer and even more data-rich.<\/p>\n\n\n\n

What\u2019s coming next started back in 2002, when the International Maritime Organization began requiring most internationally bound commercial vessels to employ Class A AIS transmitters. This equipment dynamically broadcasts vessel AIS information (such as vessel name, position, course, speed and Maritime Mobile Service Identity) on two dedicated AIS channels: VHF channels 87B and 88B. The information is broadcast every two to 10 seconds, based on vessel speed, at 2 or 12.5 watts. Class A AIS operates on the self-organized time-division multiple access (SOTDMA) channel-sharing scheme, which is coordinated within the AIS transmission hierarchy. <\/p>\n\n\n\n

In 2006, the AIS standards committee announced specifications for Class B AIS transmitters, which were aimed primarily at recreational mariners. These became commercially available in 2008. Class B AIS also broadcasts on the same two channels, but at 2 watts and a static reporting rate of once every 30 seconds, using the carrier sense time division multiple access (CSTDMA) scheme. Hence the designation Class B\/CS.<\/p>\n\n\n\n

While the acronyms are alphabet soup, the important bit is that SOTDMA transmitters pre-announce the AIS channel time slots that they intend to employ and then broadcast accordingly, whereas CSTDMA systems \u201cpolitely\u201d listen for open slots. If an opening doesn\u2019t exist when a CSTDMA transmission is timed to transpire, it retries 10 random times and then waits\u2014in 30-second increments\u2014for a window. In crowded waters, this scheme can sometimes equate to several skipped transmissions. While this is irrelevant for a sloop that\u2019s sailing at 5 knots and can still listen for incoming AIS signals, it\u2019s a bigger concern aboard rides that can cruise in the low to mid-20s, or faster.<\/p>\n\n\n\n

Class B\/SO transmitters arrived in 2013, offering several advantages. They use the SOTDMA scheme and report their AIS information once every five to 30 seconds at 2 or 5 watts of power. While Class B\/SO transmitters were initially aimed at non-SOLAS-class vessels, their bolstered transmission power increases their range, and their SOTDMA channel-sharing scheme helps ensure that more transmissions will be heard by other AIS users in busy waters.<\/p>\n\n\n\n

\u201cEverything we make now is on the newer platform,\u201d says Jim McGowan, Raymarine\u2019s Americas marketing manager, referring to Class B\/SO technology. Other leading manufacturers do the same.<\/p>\n\n\n\n

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\n\t\t\t\t\t\"Raymarine\" <\/div>\n\t\t\t\n\t\t\t\n
\n A Raymarine AIS transmitter with its data \u00adoverlaid atop a vector chart. Raymarine \u00adtransmitters are now being made with the newer\u00a0Class B\/SO transmitter technology.<\/span>\n Courtesy The Manufacturer<\/span>\n\n\t\t\t\t <\/figcaption>\n <\/section>\n\t\t\n\n\n

Another recent and positive change has been the integration of AIS within some VHF radios. \u201cI\u2019m pleased that regular VHF manufacturers are putting AIS on radios\u2014it costs nothing, and look at the benefits,\u201d says Jorge Arroyo, a US Coast Guard program analyst who helps develop AIS regulations and standards. He says we eventually might see VHF radios with listen-only AIS receivers for less than $200. <\/p>\n\n\n\n

In 2019, Vesper Marine unveiled its revolutionary Cortex safety and communications platform<\/a>. It put AIS, cellular, Digital Selective Calling, VHF and Wi-Fi communications onto a single, user-friendly software-based platform that combines with a belowdecks black-box processor (with a built-in Class B\/SO transmitter), one or more handsets, and two smartphone apps. Cortex users get smartphone-\u00adstyle operations instead of clunky VHF radios buttons and knobs. The system has a touchscreen, six hard buttons, and an iPod-like rotary wheel and central selector. \u201cWe were keen to simplify the experience and make it safer to use,\u201d says Carl Omundsen, Vesper\u2019s chief product officer and company co-founder.<\/p>\n\n\n\n

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\n\t\t\t\t\t\"Cortex\" <\/div>\n\t\t\t\n\t\t\t\n
\n Garmin\u2019s Cortex consists of one or more handsets, two smartphone apps and a belowdecks black box.<\/span>\n Courtesy The Manufacturer<\/span>\n\n\t\t\t\t <\/figcaption>\n <\/section>\n\t\t\n\n\n

Garmin acquired Vesper in January, largely to acquire Cortex. \u201cWe have no plans to change the current product,\u201d says Dave Dunn, Garmin\u2019s senior director of marine sales. <\/p>\n\n\n\n

While crystal balls are in short supply (must be the microprocessor shortage), it\u2019s fair to say that other manufacturers will emulate Cortex\u2019s smartphone-esque user interface. It\u2019s also fair to say that the sheer volume of AIS transmissions will increase in coming years as more users adopt the technology for more applications.<\/p>\n\n\n\n

In addition to collision avoidance, AIS is also used for critical jobs such as alerting crews and nearby vessels of man-overboard and life-raft scenarios, marking fishing gear, and advising mariners of navigable dangers. The Coast Guard and other international agencies regularly employ AIS to electronically augment aids to navigation, and to electronically mark other points of navigational interest. There are currently more than 500 electronic AIS aids to navigation in the United States, Arroyo says, and they\u2019re supplemented with at least another 100 during hurricane season, for things such as \u00adreopening ports after storms. <\/p>\n\n\n\n

\u201cThe USCG has them all over, on both coasts,\u201d says Jeff Robbins, Vesper Marine\u2019s CEO and co-founder. <\/p>\n\n\n\n

These electronic aids to navigation can also use AIS to transmit Application Specific Messages, which can automatically appear on navigation displays. For example, ASMs can deliver local notices to mariners information or be used to cordon off dredging areas. <\/p>\n\n\n\n

\n\n\t\t\t
\n\t\t\t\t\t\"AIS <\/div>\n\t\t\t\n\t\t\t\n
\n Garmin\u2019s AIS 800 is a Class B\/SO transmitter. If you\u2019re updating, consider a Class B\/SO.<\/span>\n Courtesy The Manufacturer<\/span>\n\n\t\t\t\t <\/figcaption>\n <\/section>\n\t\t\n\n\n

While these are all smart ways of using AIS capabilities, VHF maritime channels 87B and 88B have only so much bandwidth. To address this issue, international bodies, including the Coast Guard, have been working to create the VHF Data Exchange System (VDES). This two-way \u00adcommunications system, once operational, will allow ships, satellites, and shore stations to transmit and receive high-speed data in a sort of super-AIS data ecosystem. <\/p>\n\n\n\n

In this brave new world, which is expected to begin unfurling between 2025 and 2035, users will be able to buy a single VDES box that will bundle multiple communication frequencies (similar to how smartphones juggle Wi-Fi, cellular and Bluetooth frequencies). <\/em><\/p>\n\n\n\n

\u201cThe goal with VDES is to move traffic off AIS so that AIS is only for collision avoidance,\u201d Arroyo says. \u201cAll other traffic will be moved to VDES channels.\u201d <\/p>\n\n\n\n

VDES will have four structural components: AIS, VDE<\/em> Satellite, VDE Terrestrial and ASM channels. VDES will collectively occupy 18 frequencies: two for long-range (satellite) AIS, two for regular AIS, two for ASMs, six satellite uplink channels and six satellite downlink channels. <\/p>\n\n\n\n

\u201cThe AIS frequencies will remain for government data. The others are open,\u201d Arroyo says.  \u201cReal-time weather could be the killer app.\u201d His hope is that ships will be able to broadcast their real-time weather information and create mesh networks that repeat this data across to shore stations and to satellites. <\/p>\n\n\n\n

While VDES promises to carry a lot of data, today\u2019s AIS equipment will continue to operate safely long after VDES rolls out. \u201cVDES is in the stratosphere, but it will trickle down,\u201d Dunn says. <\/p>\n\n\n\n

And Cortex is already built to receive and decode eight channels in parallel. \u201cWe are currently using five, so there are three in reserve,\u201d Omundsen says. \u201cIn 10 years, no one will know or care about AIS\u2014it will just be cool functionality, along with VHF, DSC and VDES.\u201d <\/p>\n\n\n\n

As with most communications technologies, VDES is internationally regulated, but the features are evolving faster than the regulations do. This means that AIS will be rolled into a bigger communication platform, and its safety margins should improve as other communications are moved to separate frequencies. <\/p>\n\n\n\n

And if Arroyo\u2019s \u201ckiller app\u201d concept of relaying real-time weather is realized, this data could possibly be helpful to government agencies for weather forecasts and modeling.  <\/p>\n\n\n\n

While these upsides are big, the downsides are minimal. Existing AIS transmitters and listen-only receivers will continue to provide collision-\u00adavoidance awareness, so there will be no immediate need to upgrade hardware. VDES boxes won\u2019t be free, of course, but\u2014given that they will likely be software-based platforms (like Cortex)\u2014they should come ready for future upgrades.<\/p>\n\n\n\n

So, if you\u2019re in the market for a new AIS setup, consider a Class B\/SO transmitter. If you\u2019re an early adopter, Cortex will put you ahead of the pack right now.<\/p>\n\n\n\n

If your AIS and VHF radio equipment is contemporary, just continue watching this space. The future of VDES looks bright.<\/p>\n\n\n\n

David Schmidt is <\/em>CW\u2019s electronics editor and occasionally writes on other gear topics.<\/em><\/p>\n\n\n\n

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Antenna Matters<\/h3>\n\n\n\n

\u201cAIS works only as well as its antenna system,\u201d says Raymarine\u2019s Jim \u00adMcGowan, adding that it\u2019s best to invest in an antenna designed for AIS. \u201cRunning a dedicated antenna is better\u201d than employing an AIS\/VHF splitter. \u00adMcGowan points to \u00adDigital Antenna, Glomex and Shakespeare as good places to start shopping. <\/p>\n\n\n\n

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Vendor List<\/h3>\n\n\n\n